[fix](trx-frontend-http): give satellite passes their own page

Pass predictions were a third view inside the Weather Satellite Decoder card,
under Digital modes — a planning tool filed behind a decoder toggle, beside the
FT8 and WEFAX panels it has nothing to do with.  Nothing about knowing when a
bird comes over belongs there.

Move them to /satellites, reached from Tools alongside Statistics, Recorder,
Settings and About: occasional destinations that live behind that menu rather
than taking a slot in the operating strip.  Adding a sixth strip button wrapped
the phone nav onto two rows and cost the desktop strip its labels at 1280px, so
the tab is hidden from the strip exactly the way its four peers already are —
the nav is byte-for-byte what it was.

The prediction code moves out of sat.ts into its own plugin that loads with the
page, so the decoder card no longer carries it.  Countdowns stop when the page
is hidden and each visit reloads, since passes go stale while it is closed.
The server grows a /satellites index route so a deep link or a refresh serves
the SPA shell rather than a 404.

Closes #47

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SyX26FCpMQxiBoC7r5K1A7
Signed-off-by: Stan Grams <sjg@haxx.space>

Cargo.lock

@@ -3300,6 +3300,7 @@ dependencies = [
  "trx-ftx",
  "trx-protocol",
  "trx-reporting",
+ "trx-sstv",
  "trx-vdes",
  "trx-wefax",
  "trx-wspr",
@@ -3307,6 +3308,16 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "trx-sstv"
+version = "0.1.0"
+dependencies = [
+ "base64",
+ "png",
+ "tracing",
+ "trx-core",
+]
+
 [[package]]
 name = "trx-vdes"
 version = "0.1.0"

Cargo.toml

@@ -12,6 +12,7 @@ members = [
     "src/decoders/trx-ftx",
     "src/decoders/trx-rds",
     "src/decoders/trx-vdes",
+    "src/decoders/trx-sstv",
     "src/decoders/trx-wefax",
     "src/decoders/trx-wspr",
     "src/trx-core",

docs/Spectrum-Controls-Rework.md

@@ -0,0 +1,116 @@
+# Spectrum Controls — Visual Rework
+
+The strip between the spectrum and the radio controls (`#spectrum-controls`)
+holds eight controls in two groups. This proposes how it should *look*.
+
+Every control stays, in its current order, with its current name and its
+current behaviour. Nothing here changes what a button does, what commits when,
+or what is stored. It is a styling and layout change.
+
+*Status: implemented. Kept as the record of what was changed and why.*
+
+---
+
+## What it looks like now
+
+```
+Bandwidth [ 12 ] kHz  [Set] [Auto BW] [Sweet-spot]            Peak Hold [2 s] Floor [-115] dB Range [90] dB [Auto] Contrast [——●——] 1.0
+```
+
+Four problems, all of them visual:
+
+**1. Four different control heights on one line.** The bare number inputs, the
+buttons, the `select` and the range slider are each sized by their own rule, so
+nothing shares a baseline and the row reads as a pile rather than a strip.
+
+**2. Units are loose text.** `kHz`, `dB`, `dB` and the contrast value `1.0` are
+text nodes sitting outside the control they belong to, separated from it by a
+gap the same size as the gap between unrelated controls. The eye has to work
+out which number owns which unit.
+
+**3. A quarter of the strip is a hole.** `justify-content: space-between` puts
+about 250 px of nothing in the middle at 1600 px, and the two groups read as
+two unrelated things because the only thing between them is emptiness.
+
+**4. The groups stagger between 1100 and 1400 px.** The bandwidth group wraps
+to two lines while the level group stays on one, so the level group floats at a
+height of its own, aligned with neither line of the group beside it. This is
+the worst of it, and it happens at a common window width.
+
+Two smaller things: 24 px controls are below any touch-target guideline, and
+the contrast readout has no fixed width, so the row twitches as the value
+changes between `1.0` and `0.9`.
+
+## Proposed
+
+**One control height, units inside their field, and a rule where the clusters
+meet.**
+
+- **A field is one box.** Label, value and unit share a single bordered box —
+  `Bandwidth │ 12.0 │ kHz` — so a number and its unit can never be read apart.
+  Fields, buttons, the peak-hold select and the contrast slider are all 1.7 rem
+  tall, on 44 px targets under a coarse pointer.
+- **A rule, not a hole.** The two clusters are separated by a thin vertical
+  rule with normal spacing either side. The slack goes to a flexible spacer, so
+  the strip is left-aligned rather than pushed apart.
+- **A cluster never splits.** Each cluster is `nowrap`; the container wraps. If
+  a cluster does not fit on the line it drops whole to the next one,
+  left-aligned with the one above. No staggering, at any width.
+- **Rules fall away at line starts.** A cluster that begins a line has no rule
+  hanging off its left edge.
+- **The contrast readout gets a fixed, tabular slot**, so the row is still.
+
+Below the existing mobile breakpoint the strip already stacks; the same field
+component applies there, which is most of what makes it look deliberate.
+
+## What this does not change
+
+`Set` stays. `Auto BW` and `Auto` keep their names, even though they mean
+different things — that is a naming question, not a styling one. Sweet-spot
+stays where it is and keeps its behaviour. Nothing gains or loses persistence.
+Nothing moves into a popover, and no control is hidden behind a click.
+
+Those are all worth arguing about separately; a note of them is at the end of
+this file so the arguments are not lost.
+
+## Implementation
+
+One pass, no behaviour touched:
+
+1. `.spectrum-field` and `.spectrum-btn` in `style.css`, replacing the six
+   per-id rules (`#spectrum-bw-input`, `#spectrum-floor-input`,
+   `#spectrum-range-input`, `#spectrum-bw-label`, `#spectrum-floor-label`,
+   `#spectrum-range-label`) that currently repeat the same declarations.
+2. Markup in `index.html`: the loose `kHz` / `dB` text nodes move inside their
+   label, which keeps every id and every event handler exactly where it is.
+3. `#spectrum-controls` becomes a wrapping flex row with a spacer;
+   `#spectrum-bw-row` and `#spectrum-level-row` become `nowrap` clusters with a
+   left rule.
+4. The mobile block in the media query drops the rules it no longer needs.
+
+`app.ts` is not touched. Every id survives, so the existing handlers, the
+`spectrum-layout.mjs` geometry test and the broadcast-layout highlight all keep
+working.
+
+### Tests
+
+Extend `spectrum-layout.mjs`, which already measures this area:
+
+- Every control in the strip shares one height, at 1600, 1200 and 900 px.
+- No two clusters sit at different vertical offsets on the same line — the
+  staggering bug, asserted directly.
+- The strip never overflows its container and never overlaps the hint line.
+
+---
+
+## Noted for later, not proposed here
+
+Behavioural observations from reading the code, kept so they are not lost:
+
+- `Auto BW` (filter) and `Auto` (display scaling) are both called Auto, 600 px
+  apart.
+- `Floor`, `Range` and `Contrast` are not persisted; `Peak Hold` is.
+- `Auto` and `Auto BW` are one-shot: no state, nothing to turn off.
+- `Sweet-spot` retunes the SDR and waits up to 1.4 s per candidate centre, with
+  no busy indication.
+- Contrast resets on a double-click that nothing advertises.

src/decoders/trx-sstv/Cargo.toml

@@ -0,0 +1,14 @@
+# SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+[package]
+name = "trx-sstv"
+version.workspace = true
+edition = "2021"
+
+[dependencies]
+trx-core = { path = "../../trx-core" }
+base64 = "0.22"
+png = "0.17"
+tracing = "0.1"

src/decoders/trx-sstv/examples/round_trip_png.rs

@@ -0,0 +1,91 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Encode a test card, decode it back, write both as PNGs to a directory.
+//!
+//! `cargo run -p trx-sstv --example round_trip_png -- /tmp/out`
+
+use trx_sstv::encode::{encode, Frame};
+use trx_sstv::mode::mode_for_vis;
+use trx_sstv::{ImageCanvas, SstvConfig, SstvDecoder, SstvEvent};
+
+fn main() {
+    let dir = std::env::args().nth(1).unwrap_or_else(|| ".".into());
+    for vis in [44u8, 60, 12, 8, 95] {
+        let mode = mode_for_vis(vis).expect("mode in table");
+        let (w, h) = (usize::from(mode.width), usize::from(mode.height));
+        let mut rgb = vec![0u8; w * h * 3];
+        for y in 0..h {
+            for x in 0..w {
+                let at = (y * w + x) * 3;
+                let (r, g, b) = if y < h / 3 {
+                    [
+                        (255u8, 255u8, 255u8),
+                        (255, 255, 0),
+                        (0, 255, 255),
+                        (0, 255, 0),
+                        (255, 0, 255),
+                        (255, 0, 0),
+                        (0, 0, 255),
+                        (0, 0, 0),
+                    ][x * 8 / w]
+                } else if y < 2 * h / 3 {
+                    let t = (x * 255 / w) as u8;
+                    (t, 255 - t, ((y * 255) / h) as u8)
+                } else {
+                    // Diagonal stripes: a line-timing error shows up as a kink.
+                    if ((x + y) / 16) % 2 == 0 {
+                        (240, 240, 40)
+                    } else {
+                        (20, 20, 90)
+                    }
+                };
+                rgb[at] = r;
+                rgb[at + 1] = g;
+                rgb[at + 2] = b;
+            }
+        }
+        let name = mode.name.replace(' ', "-");
+        let mut sent = ImageCanvas::new(w, h);
+        for y in 0..h {
+            sent.put_row(y, &rgb[y * w * 3..(y + 1) * w * 3]);
+        }
+        std::fs::write(
+            format!("{dir}/{name}-sent.png"),
+            sent.to_png().expect("png"),
+        )
+        .expect("write");
+
+        let frame = Frame {
+            width: w,
+            height: h,
+            rgb: &rgb,
+        };
+        let mut audio = encode(mode, &frame, 48_000);
+        audio.extend(std::iter::repeat_n(0.0, 4800));
+        let mut decoder = SstvDecoder::new(48_000, SstvConfig::default());
+        let mut got = None;
+        for block in audio.chunks(1024) {
+            for event in decoder.process_samples(block) {
+                if let SstvEvent::Complete(image) = event {
+                    got = Some(image);
+                }
+            }
+        }
+        let image = got.expect("no image decoded");
+        let mut canvas = ImageCanvas::new(w, h);
+        for y in 0..h {
+            canvas.put_row(y, &image.rgb[y * w * 3..(y + 1) * w * 3]);
+        }
+        std::fs::write(
+            format!("{dir}/{name}-decoded.png"),
+            canvas.to_png().expect("png"),
+        )
+        .expect("write");
+        println!(
+            "{}: {} lines, complete={}",
+            mode.name, image.lines, image.complete
+        );
+    }
+}

src/decoders/trx-sstv/src/config.rs

@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! SSTV decoder configuration.
+
+/// Settings for [`crate::decoder::SstvDecoder`].
+#[derive(Debug, Clone, Default)]
+pub struct SstvConfig {
+    /// VIS code of a mode to assume when no header is heard, so tuning in
+    /// part-way through a transmission still produces a picture. `None` means
+    /// wait for a header, which is the safe default: guessing wrong yields a
+    /// convincing image of nothing.
+    pub force_mode: Option<u8>,
+    /// Directory for saved PNGs. `None` keeps images in memory only.
+    pub output_dir: Option<String>,
+}

src/decoders/trx-sstv/src/decoder.rs

@@ -0,0 +1,659 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! The decoder: audio in, pictures out.
+//!
+//! Reception is a small state machine. It listens for a VIS header, and once
+//! one names a mode it walks the transmission a line at a time, sampling each
+//! scan at the offsets the mode's segment list gives. Every line is looked for
+//! at the time the mode says it should arrive, then nudged into place by the
+//! sync pulse actually found near it — a transmitter's clock and a receiver's
+//! sound card never agree exactly, and over two minutes of Martin M1 an
+//! uncorrected error of a few parts per million visibly shears the picture.
+//!
+//! Rows are emitted as they are decoded so a picture can be watched arriving,
+//! which is most of the appeal of the mode.
+
+use crate::config::SstvConfig;
+use crate::demod::FreqDemod;
+use crate::image::ImageCanvas;
+use crate::mode::{level_from_hz, mode_for_vis, Channel, ColorModel, SstvMode};
+use crate::vis::find_vis;
+
+/// Anything below this is the sync pulse rather than picture: black is 1500 Hz
+/// and sync is 1200 Hz, so the line sits between them.
+const SYNC_THRESHOLD_HZ: f32 = 1350.0;
+
+/// How much of the signal to keep while hunting for a header. A header is 940
+/// ms; two seconds leaves room for one to straddle several blocks of audio.
+const SEARCH_HISTORY_MS: f64 = 2000.0;
+
+/// From the start bit to the end of the stop bit: ten 30 ms cells. A header
+/// search must never retire a stretch shorter than this, or a start bit split
+/// across two blocks of audio is dismissed on half a view of it.
+const HEADER_SPAN_MS: f64 = 330.0;
+
+/// How far from its predicted position a line's sync pulse is looked for.
+const SYNC_SEARCH_MS: f64 = 12.0;
+
+/// Fraction of the observed timing error applied to the next line. Damped,
+/// because a sync pulse found in noise is worth less than the prediction.
+const SYNC_CORRECTION: f64 = 0.45;
+
+/// Consecutive lines with no sync pulse anywhere near the prediction before
+/// the transmission is taken to have ended.
+const MISSING_SYNC_LIMIT: u32 = 8;
+
+/// What the decoder has to say.
+#[derive(Debug, Clone)]
+pub enum SstvEvent {
+    /// A header was decoded and reception has begun.
+    Started {
+        vis: u8,
+        mode: &'static str,
+        width: u16,
+        height: u16,
+    },
+    /// One image row is ready, as RGB triples.
+    Row { line: u16, rgb: Vec<u8> },
+    /// Reception finished — at the bottom of the frame, or because the signal
+    /// went away. Carries the picture either way.
+    Complete(SstvImage),
+}
+
+/// A received picture.
+#[derive(Debug, Clone)]
+pub struct SstvImage {
+    pub vis: u8,
+    pub mode: &'static str,
+    pub width: u16,
+    pub height: u16,
+    /// Rows actually received, which is the height only if it ran to the end.
+    pub lines: u16,
+    /// Whether the whole frame arrived.
+    pub complete: bool,
+    /// RGB triples, `width * height * 3` bytes. Rows never received are grey.
+    pub rgb: Vec<u8>,
+    /// When reception started, in milliseconds since the epoch.
+    pub started_ms: i64,
+}
+
+impl SstvImage {
+    /// The picture as a canvas, for saving or encoding.
+    pub fn canvas(&self) -> ImageCanvas {
+        let width = usize::from(self.width);
+        let mut canvas = ImageCanvas::new(width, usize::from(self.height));
+        for (y, row) in self.rgb.chunks(width * 3).enumerate() {
+            canvas.put_row(y, row);
+        }
+        canvas
+    }
+
+    /// The picture as PNG bytes.
+    pub fn to_png(&self) -> Result<Vec<u8>, String> {
+        self.canvas().to_png()
+    }
+
+    /// The picture as a base64 PNG, for the journey to a client.
+    pub fn to_png_base64(&self) -> Result<String, String> {
+        self.canvas().to_png_base64()
+    }
+
+    /// Write the picture into `dir`, named for when and where it arrived.
+    pub fn save_png(
+        &self,
+        dir: &std::path::Path,
+        freq_hz: u64,
+    ) -> Result<std::path::PathBuf, String> {
+        self.canvas()
+            .save_png(dir, freq_hz, self.mode, &stamp(self.started_ms))
+    }
+}
+
+/// `YYYYMMDDTHHMMSSZ` for a millisecond timestamp, for file names that sort.
+fn stamp(ms: i64) -> String {
+    let secs = ms.div_euclid(1000);
+    let (days, rest) = (secs.div_euclid(86_400), secs.rem_euclid(86_400));
+    let (year, month, day) = civil_from_days(days);
+    let (hour, minute, second) = (rest / 3600, (rest % 3600) / 60, rest % 60);
+    format!("{year:04}{month:02}{day:02}T{hour:02}{minute:02}{second:02}Z")
+}
+
+/// Days since the Unix epoch to a calendar date (Howard Hinnant's algorithm).
+fn civil_from_days(days: i64) -> (i64, u32, u32) {
+    let z = days + 719_468;
+    let era = z.div_euclid(146_097);
+    let doe = z.rem_euclid(146_097);
+    let yoe = (doe - doe / 1460 + doe / 36_524 - doe / 146_096) / 365;
+    let y = yoe + era * 400;
+    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+    let mp = (5 * doy + 2) / 153;
+    let d = (doy - (153 * mp + 2) / 5 + 1) as u32;
+    let m = if mp < 10 { mp + 3 } else { mp - 9 } as u32;
+    (if m <= 2 { y + 1 } else { y }, m, d)
+}
+
+enum State {
+    /// Listening for a header.
+    Searching,
+    Receiving(Box<Reception>),
+}
+
+struct Reception {
+    mode: &'static SstvMode,
+    canvas: ImageCanvas,
+    /// Absolute sample index at which the next transmitted line begins.
+    next_line: f64,
+    /// Next image row to write.
+    row: u16,
+    started_ms: i64,
+    missing_syncs: u32,
+    /// Set until the first line has been decoded. A VIS header ends exactly
+    /// where the picture begins, so the first line is already aligned — and a
+    /// search would find the header's own 30 ms stop bit, which is at the sync
+    /// frequency and sits immediately before the picture.
+    first_line: bool,
+    /// Robot 36 sends one chroma channel per line and expects the decoder to
+    /// carry the other over from the line before.
+    last_chroma_r: Option<Vec<u8>>,
+    last_chroma_b: Option<Vec<u8>>,
+}
+
+pub struct SstvDecoder {
+    sample_rate: u32,
+    config: SstvConfig,
+    demod: FreqDemod,
+    /// Instantaneous frequency, one entry per audio sample. Delayed by the
+    /// demodulator's group delay, which is constant and so shifts the whole
+    /// stream — header and lines alike — without disturbing their spacing.
+    freqs: Vec<f32>,
+    /// Absolute index of `freqs[0]`, so positions survive the buffer being
+    /// trimmed.
+    base: u64,
+    /// Absolute index the header search has already covered.
+    searched_to: u64,
+    state: State,
+}
+
+impl SstvDecoder {
+    pub fn new(sample_rate: u32, config: SstvConfig) -> Self {
+        Self {
+            sample_rate,
+            config,
+            demod: FreqDemod::new(sample_rate),
+            freqs: Vec::new(),
+            base: 0,
+            searched_to: 0,
+            state: State::Searching,
+        }
+    }
+
+    /// Whether a picture is currently arriving.
+    pub fn is_receiving(&self) -> bool {
+        matches!(self.state, State::Receiving(_))
+    }
+
+    /// Feed a block of mono audio. Returns whatever it produced.
+    pub fn process_samples(&mut self, samples: &[f32]) -> Vec<SstvEvent> {
+        self.demod.process_into(samples, &mut self.freqs);
+        let mut events = Vec::new();
+        loop {
+            let progressed = match self.state {
+                State::Searching => self.try_start(&mut events),
+                State::Receiving(_) => self.try_line(&mut events),
+            };
+            if !progressed {
+                break;
+            }
+        }
+        self.trim();
+        events
+    }
+
+    /// Abandon a reception in progress, returning the picture so far.
+    pub fn reset(&mut self) -> Vec<SstvEvent> {
+        let mut events = Vec::new();
+        if let State::Receiving(reception) = std::mem::replace(&mut self.state, State::Searching) {
+            events.push(SstvEvent::Complete(finish(&reception)));
+        }
+        self.demod.reset();
+        self.freqs.clear();
+        self.base = 0;
+        self.searched_to = 0;
+        events
+    }
+
+    /// Look for a header, or for a bare sync pulse when the mode is forced.
+    fn try_start(&mut self, events: &mut Vec<SstvEvent>) -> bool {
+        let from = self.searched_to.saturating_sub(self.base) as usize;
+        if from >= self.freqs.len() {
+            return false;
+        }
+
+        if let Some(hit) = find_vis(&self.freqs, self.sample_rate, from) {
+            if let Some(mode) = mode_for_vis(hit.code) {
+                self.begin(mode, self.base + hit.image_start as u64, events);
+                return true;
+            }
+            // A header that parses but names a mode this decoder does not know
+            // is still a header: skip past it rather than finding it again.
+            tracing::debug!(vis = hit.code, "SSTV: unsupported mode");
+            self.searched_to = self.base + hit.image_start as u64;
+            return true;
+        }
+
+        // Tuning in mid-transmission means no header to find. With a mode
+        // named in the configuration, the first sync pulse is enough to start.
+        if let Some(mode) = self.config.force_mode.and_then(mode_for_vis) {
+            if let Some(sync) = self.find_sync(from, self.freqs.len(), mode) {
+                let line_start = (self.base + sync as u64) as f64
+                    - ms_to_samples(mode.sync_offset_ms, self.sample_rate);
+                self.begin_at(mode, line_start.max(0.0), events);
+                return true;
+            }
+        }
+
+        // Nothing yet. Rewind the cursor by a header's worth of samples before
+        // marking the buffer searched: audio arrives in blocks of a few
+        // milliseconds, so the search regularly runs over a start bit that is
+        // only half here. Advancing past it would retire the header for good
+        // on the strength of a partial view of it.
+        let unsearchable = ms_to_samples(HEADER_SPAN_MS, self.sample_rate) as u64;
+        let end = self.base + self.freqs.len() as u64;
+        self.searched_to = self.searched_to.max(end.saturating_sub(unsearchable));
+        false
+    }
+
+    fn begin(&mut self, mode: &'static SstvMode, image_start: u64, events: &mut Vec<SstvEvent>) {
+        self.begin_at(mode, image_start as f64, events);
+    }
+
+    fn begin_at(&mut self, mode: &'static SstvMode, line_start: f64, events: &mut Vec<SstvEvent>) {
+        events.push(SstvEvent::Started {
+            vis: mode.vis,
+            mode: mode.name,
+            width: mode.width,
+            height: mode.height,
+        });
+        self.state = State::Receiving(Box::new(Reception {
+            mode,
+            canvas: ImageCanvas::new(usize::from(mode.width), usize::from(mode.height)),
+            next_line: line_start,
+            row: 0,
+            started_ms: now_ms(),
+            missing_syncs: 0,
+            first_line: true,
+            last_chroma_r: None,
+            last_chroma_b: None,
+        }));
+    }
+
+    /// Decode one transmitted line, if all of it has arrived.
+    fn try_line(&mut self, events: &mut Vec<SstvEvent>) -> bool {
+        let State::Receiving(reception) = &mut self.state else {
+            return false;
+        };
+        let mode = reception.mode;
+        let line_samples = ms_to_samples(mode.line_ms, self.sample_rate);
+        let margin = ms_to_samples(SYNC_SEARCH_MS, self.sample_rate);
+
+        let start = reception.next_line;
+        // Enough for the line's own scans, and for the sync search to reach as
+        // far ahead as it looks — no further. Demanding the search margin past
+        // the end of every line would cost the last line of every picture,
+        // which is exactly where the transmission stops.
+        let sync_reach = start + ms_to_samples(mode.sync_offset_ms, self.sample_rate) + margin;
+        let end = (start + line_samples).max(sync_reach);
+        let available = (self.base + self.freqs.len() as u64) as f64;
+        if end > available {
+            return false;
+        }
+        // The line may begin before what is still buffered if the caller fed a
+        // huge block; nothing can be done about that but skip forward.
+        if start < self.base as f64 {
+            reception.next_line = self.base as f64;
+            return true;
+        }
+
+        // Line up on the sync pulse near where this line is predicted to be.
+        let expected_sync = start + ms_to_samples(mode.sync_offset_ms, self.sample_rate);
+        let from = (expected_sync - margin).max(self.base as f64) as u64;
+        let to = (expected_sync + margin) as u64;
+        let searching = !matches!(&self.state, State::Receiving(r) if r.first_line);
+        let found = if searching {
+            self.find_sync_between(from, to, mode)
+        } else {
+            None
+        };
+        let State::Receiving(reception) = &mut self.state else {
+            return false;
+        };
+        let start = match found {
+            Some(sync_at) => {
+                reception.missing_syncs = 0;
+                let error = sync_at as f64 - expected_sync;
+                reception.next_line += error * SYNC_CORRECTION;
+                reception.next_line
+            }
+            None if reception.first_line => start,
+            None => {
+                reception.missing_syncs += 1;
+                start
+            }
+        };
+
+        if reception.missing_syncs >= MISSING_SYNC_LIMIT {
+            let image = finish(reception);
+            self.state = State::Searching;
+            self.searched_to = self.base + self.freqs.len() as u64;
+            events.push(SstvEvent::Complete(image));
+            return true;
+        }
+
+        // Sample every scan of the line, then colour the rows.
+        let mut scans: Vec<(Channel, Vec<u8>)> = Vec::new();
+        for (channel, offset_ms, ms) in mode.scans() {
+            let pixels = mode.scan_pixels(channel);
+            let at = start + ms_to_samples(offset_ms, self.sample_rate);
+            let values = sample_scan(&self.freqs, self.base, at, ms, pixels, self.sample_rate);
+            scans.push((channel, values));
+        }
+
+        let State::Receiving(reception) = &mut self.state else {
+            return false;
+        };
+        let rows = compose_rows(reception, &scans);
+        for (offset, row) in rows.into_iter().enumerate() {
+            let line = reception.row + offset as u16;
+            reception.canvas.put_row(usize::from(line), &row);
+            events.push(SstvEvent::Row { line, rgb: row });
+        }
+        reception.first_line = false;
+        reception.row += mode.lines_per_transmission;
+        reception.next_line += line_samples;
+
+        if reception.row >= mode.height {
+            let image = finish(reception);
+            self.state = State::Searching;
+            self.searched_to = self.base + self.freqs.len() as u64;
+            events.push(SstvEvent::Complete(image));
+        }
+        true
+    }
+
+    /// First sync pulse of about the right length in `freqs[from..to]`,
+    /// as an index of its leading edge.
+    ///
+    /// Works on a smoothed copy of the window: a sync pulse is 1200 Hz, where
+    /// the raw per-sample estimate swings by ±95 Hz, so single samples cross
+    /// and re-cross the threshold throughout a pulse and no run is ever long
+    /// enough. Pixels are sampled from the raw signal, where averaging over
+    /// the pixel does the same job without blurring across its edges.
+    fn find_sync(&self, from: usize, to: usize, mode: &SstvMode) -> Option<usize> {
+        let want = sync_ms(mode);
+        let min_run = (ms_to_samples(want, self.sample_rate) * 0.6) as usize;
+        // A sync pulse ends. Silence and a dead carrier demodulate to near
+        // zero, which is below the threshold too, and without an upper bound a
+        // decoder left running on an empty channel finds sync everywhere and
+        // fills the picture with noise it invented.
+        let max_run = (ms_to_samples(want, self.sample_rate) * 3.0) as usize;
+        let to = to.min(self.freqs.len());
+        if from >= to {
+            return None;
+        }
+        // Reach past the end of the search window by a whole pulse: a sync
+        // starting at the last moment the window allows still has to be
+        // measurable to its full length, or it is rejected for being short and
+        // the line it belongs to goes unaligned.
+        let pad = ms_to_samples(want + 2.0, self.sample_rate) as usize;
+        let window_from = from.saturating_sub(pad);
+        let window_to = (to + pad).min(self.freqs.len());
+        let smoothed = crate::demod::smooth(
+            &self.freqs[window_from..window_to],
+            ms_to_samples(1.0, self.sample_rate) as usize,
+        );
+
+        let mut i = from - window_from;
+        let scan_to = to - window_from;
+        while i < scan_to {
+            if smoothed[i] >= SYNC_THRESHOLD_HZ {
+                i += 1;
+                continue;
+            }
+            let mut run = 0;
+            while i + run < smoothed.len() && smoothed[i + run] < SYNC_THRESHOLD_HZ {
+                run += 1;
+            }
+            if run >= min_run && run <= max_run {
+                return Some(window_from + i);
+            }
+            i += run.max(1);
+        }
+        None
+    }
+
+    /// As [`Self::find_sync`], over an absolute index range.
+    fn find_sync_between(&self, from: u64, to: u64, mode: &SstvMode) -> Option<u64> {
+        let from = from.saturating_sub(self.base) as usize;
+        let to = to.saturating_sub(self.base) as usize;
+        if from >= self.freqs.len() {
+            return None;
+        }
+        self.find_sync(from, to, mode)
+            .map(|at| self.base + at as u64)
+    }
+
+    /// Drop what is behind the decoder, so a long reception does not grow the
+    /// buffer without bound.
+    fn trim(&mut self) {
+        let keep_from = match &self.state {
+            State::Searching => {
+                let history = ms_to_samples(SEARCH_HISTORY_MS, self.sample_rate) as u64;
+                (self.base + self.freqs.len() as u64).saturating_sub(history)
+            }
+            State::Receiving(reception) => {
+                let margin = ms_to_samples(SYNC_SEARCH_MS * 2.0, self.sample_rate) as u64;
+                (reception.next_line as u64).saturating_sub(margin)
+            }
+        };
+        if keep_from <= self.base {
+            return;
+        }
+        let drop = (keep_from - self.base) as usize;
+        if drop >= self.freqs.len() {
+            self.freqs.clear();
+        } else {
+            self.freqs.drain(..drop);
+        }
+        self.base = keep_from;
+        self.searched_to = self.searched_to.max(self.base);
+    }
+}
+
+/// The sync pulse length of a mode, read out of its own segment list.
+fn sync_ms(mode: &SstvMode) -> f64 {
+    mode.segments
+        .iter()
+        .find_map(|segment| match segment {
+            crate::mode::Segment::Sync(ms) => Some(*ms),
+            _ => None,
+        })
+        .unwrap_or(9.0)
+}
+
+/// Milliseconds since the epoch, for stamping a picture with when it arrived.
+fn now_ms() -> i64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_millis() as i64
+}
+
+fn ms_to_samples(ms: f64, sample_rate: u32) -> f64 {
+    ms / 1000.0 * f64::from(sample_rate)
+}
+
+/// Average the frequency across each pixel's window and turn it into a level.
+///
+/// The middle 60% of the window is used: a pixel's edges carry the
+/// demodulator's transition from the pixel before, and including them smears
+/// every edge in the picture.
+fn sample_scan(
+    freqs: &[f32],
+    base: u64,
+    start: f64,
+    ms: f64,
+    pixels: usize,
+    sample_rate: u32,
+) -> Vec<u8> {
+    let mut out = Vec::with_capacity(pixels);
+    let width = ms_to_samples(ms, sample_rate) / pixels as f64;
+    for x in 0..pixels {
+        let pixel_start = start + width * x as f64;
+        let from = (pixel_start + width * 0.2 - base as f64).max(0.0) as usize;
+        let to = ((pixel_start + width * 0.8 - base as f64).max(0.0) as usize).min(freqs.len());
+        // A pixel narrower than a sample still has to produce one.
+        let (from, to) = if to > from {
+            (from, to)
+        } else {
+            let at = (pixel_start - base as f64).max(0.0) as usize;
+            (
+                at.min(freqs.len().saturating_sub(1)),
+                (at + 1).min(freqs.len()),
+            )
+        };
+        if to <= from {
+            out.push(0);
+            continue;
+        }
+        let window = &freqs[from..to];
+        let mean = window.iter().sum::<f32>() / window.len() as f32;
+        out.push(level_from_hz(mean));
+    }
+    out
+}
+
+/// Turn one line's scans into image rows.
+fn compose_rows(reception: &mut Reception, scans: &[(Channel, Vec<u8>)]) -> Vec<Vec<u8>> {
+    let mode = reception.mode;
+    let width = usize::from(mode.width);
+    let find = |channel: Channel| scans.iter().find(|(c, _)| *c == channel).map(|(_, v)| v);
+
+    match mode.color {
+        ColorModel::Rgb => {
+            let red = find(Channel::Red);
+            let green = find(Channel::Green);
+            let blue = find(Channel::Blue);
+            let mut row = vec![0u8; width * 3];
+            for x in 0..width {
+                row[x * 3] = red.and_then(|c| c.get(x).copied()).unwrap_or(0);
+                row[x * 3 + 1] = green.and_then(|c| c.get(x).copied()).unwrap_or(0);
+                row[x * 3 + 2] = blue.and_then(|c| c.get(x).copied()).unwrap_or(0);
+            }
+            vec![row]
+        }
+        ColorModel::YCrCb => {
+            let luma = find(Channel::LumaOdd).cloned().unwrap_or_default();
+            let cr = find(Channel::ChromaR).cloned().unwrap_or_default();
+            let cb = find(Channel::ChromaB).cloned().unwrap_or_default();
+            vec![ycrcb_row(&luma, &cr, &cb, width)]
+        }
+        ColorModel::YCrCbAlternating => {
+            // This line carries one chroma channel; the other is the one from
+            // the line before, which is what the mode expects a decoder to do.
+            let luma = find(Channel::LumaOdd).cloned().unwrap_or_default();
+            let chroma = find(Channel::ChromaAlternating)
+                .cloned()
+                .unwrap_or_default();
+            if reception.row.is_multiple_of(2) {
+                reception.last_chroma_r = Some(chroma);
+            } else {
+                reception.last_chroma_b = Some(chroma);
+            }
+            let neutral = vec![128u8; luma.len().max(1) / 2];
+            let cr = reception
+                .last_chroma_r
+                .clone()
+                .unwrap_or_else(|| neutral.clone());
+            let cb = reception.last_chroma_b.clone().unwrap_or(neutral);
+            vec![ycrcb_row(&luma, &cr, &cb, width)]
+        }
+        ColorModel::YCrCbPaired => {
+            let odd = find(Channel::LumaOdd).cloned().unwrap_or_default();
+            let even = find(Channel::LumaEven).cloned().unwrap_or_default();
+            let cr = find(Channel::ChromaR).cloned().unwrap_or_default();
+            let cb = find(Channel::ChromaB).cloned().unwrap_or_default();
+            vec![
+                ycrcb_row(&odd, &cr, &cb, width),
+                ycrcb_row(&even, &cr, &cb, width),
+            ]
+        }
+    }
+}
+
+/// One RGB row from luminance and chrominance, stretching the chroma scans
+/// across the width when they are narrower than it.
+fn ycrcb_row(luma: &[u8], cr: &[u8], cb: &[u8], width: usize) -> Vec<u8> {
+    let mut row = vec![0u8; width * 3];
+    let pick = |channel: &[u8], x: usize| -> f32 {
+        if channel.is_empty() {
+            return 128.0;
+        }
+        let at = x * channel.len() / width.max(1);
+        f32::from(channel[at.min(channel.len() - 1)])
+    };
+    for x in 0..width {
+        let y = if luma.is_empty() {
+            0.0
+        } else {
+            let at = x * luma.len() / width.max(1);
+            f32::from(luma[at.min(luma.len() - 1)])
+        };
+        let (r, g, b) = ycrcb_to_rgb(y, pick(cr, x), pick(cb, x));
+        row[x * 3] = r;
+        row[x * 3 + 1] = g;
+        row[x * 3 + 2] = b;
+    }
+    row
+}
+
+/// The inverse of the studio-swing conversion SSTV encoders use.
+fn ycrcb_to_rgb(y: f32, cr: f32, cb: f32) -> (u8, u8, u8) {
+    let r = 298.082 * y / 256.0 + 408.583 * cr / 256.0 - 222.921;
+    let g = 298.082 * y / 256.0 - 100.291 * cb / 256.0 - 208.120 * cr / 256.0 + 135.576;
+    let b = 298.082 * y / 256.0 + 516.412 * cb / 256.0 - 276.836;
+    (
+        r.clamp(0.0, 255.0) as u8,
+        g.clamp(0.0, 255.0) as u8,
+        b.clamp(0.0, 255.0) as u8,
+    )
+}
+
+fn finish(reception: &Reception) -> SstvImage {
+    SstvImage {
+        vis: reception.mode.vis,
+        mode: reception.mode.name,
+        width: reception.mode.width,
+        height: reception.mode.height,
+        lines: reception.canvas.filled_rows() as u16,
+        complete: reception.row >= reception.mode.height,
+        rgb: reception.canvas.rgb().to_vec(),
+        started_ms: reception.started_ms,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn file_stamps_are_utc_and_sort_in_time_order() {
+        // Known instants, checked against `date -u -r <secs>`.
+        assert_eq!(stamp(0), "19700101T000000Z");
+        assert_eq!(stamp(1_000_000_000_000), "20010909T014640Z");
+        assert_eq!(stamp(1_770_000_000_000), "20260202T024000Z");
+        // Sorting the names sorts the pictures.
+        assert!(stamp(1_770_000_000_000) < stamp(1_770_000_001_000));
+    }
+}

src/decoders/trx-sstv/src/demod.rs

@@ -0,0 +1,297 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Instantaneous frequency estimation.
+//!
+//! SSTV carries every pixel as a frequency between 1500 and 2300 Hz, and every
+//! line boundary as a 1200 Hz pulse, so one measurement serves the whole
+//! decoder: the frequency of the signal at each sample. A Hilbert transform
+//! FIR forms the analytic signal and the phase difference between consecutive
+//! samples gives the frequency.
+//!
+//! The same approach drives the WEFAX decoder, which maps the result straight
+//! to luminance. Here the frequency itself is the output, because the VIS
+//! header and the sync detector read tones far outside the pixel band.
+//!
+//! Block-based linear processing, per `docs/Optimization-Guidelines.md`: the
+//! FIR runs over a contiguous `[tail | samples]` buffer so the inner loop is
+//! straight indexing the compiler can vectorise.
+
+use std::f32::consts::PI;
+
+/// Taps for the Hilbert transform FIR. Odd, so the delay is a whole sample.
+const HILBERT_TAPS: usize = 65;
+
+/// Group delay of the FIR, in samples.
+const HILBERT_DELAY: usize = HILBERT_TAPS / 2;
+
+/// Taps for the input band-pass. Long enough to be worth having, short enough
+/// that its delay is a couple of milliseconds.
+const BANDPASS_TAPS: usize = 127;
+
+/// The band SSTV lives in: sync at 1200 Hz, black at 1500, white at 2300.
+const BAND_LOW_HZ: f32 = 900.0;
+const BAND_HIGH_HZ: f32 = 2700.0;
+
+/// Produces instantaneous frequency in Hz from real audio samples.
+pub struct FreqDemod {
+    /// Band-pass, applied first. A phase-difference frequency detector answers
+    /// whatever is loudest, so hiss outside the SSTV band steers the estimate
+    /// even when the signal is much stronger — the picture tears rather than
+    /// grows grainy. Every real decoder filters to the band first.
+    bandpass: Vec<f32>,
+    bandpass_tail: Vec<f32>,
+    coeffs: [f32; HILBERT_TAPS],
+    /// The last `HILBERT_TAPS - 1` input samples, priming the next block.
+    tail: Vec<f32>,
+    prev_i: f32,
+    prev_q: f32,
+    /// `sample_rate / 2π`, the constant turning phase step into Hz.
+    hz_per_radian: f32,
+}
+
+impl FreqDemod {
+    pub fn new(sample_rate: u32) -> Self {
+        Self {
+            bandpass: design_bandpass_fir(sample_rate),
+            bandpass_tail: vec![0.0; BANDPASS_TAPS - 1],
+            coeffs: design_hilbert_fir(),
+            tail: vec![0.0; HILBERT_TAPS - 1],
+            prev_i: 0.0,
+            prev_q: 0.0,
+            hz_per_radian: sample_rate as f32 / (2.0 * PI),
+        }
+    }
+
+    /// Band-pass a block, carrying the filter's state across the seam.
+    fn filter(&mut self, samples: &[f32]) -> Vec<f32> {
+        let taps = BANDPASS_TAPS;
+        let tail_len = taps - 1;
+        let mut work = Vec::with_capacity(tail_len + samples.len());
+        work.extend_from_slice(&self.bandpass_tail);
+        work.extend_from_slice(samples);
+
+        let mut out = Vec::with_capacity(samples.len());
+        for i in 0..samples.len() {
+            let window = &work[i..i + taps];
+            let mut acc = 0.0f32;
+            for k in 0..taps {
+                acc += self.bandpass[k] * window[taps - 1 - k];
+            }
+            out.push(acc);
+        }
+        let work_len = work.len();
+        self.bandpass_tail
+            .copy_from_slice(&work[work_len - tail_len..]);
+        out
+    }
+
+    /// Frequency in Hz for each input sample, appended to `out`.
+    ///
+    /// Output is delayed by the FIR's group delay, which is constant and so
+    /// affects only the absolute timing of the whole stream, not the spacing
+    /// between the events in it.
+    pub fn process_into(&mut self, samples: &[f32], out: &mut Vec<f32>) {
+        if samples.is_empty() {
+            return;
+        }
+        let samples = self.filter(samples);
+        let samples = samples.as_slice();
+        let taps = HILBERT_TAPS;
+        let tail_len = taps - 1;
+
+        let mut work = Vec::with_capacity(tail_len + samples.len());
+        work.extend_from_slice(&self.tail);
+        work.extend_from_slice(samples);
+
+        out.reserve(samples.len());
+        for i in 0..samples.len() {
+            let window = &work[i..i + taps];
+            let mut q = 0.0f32;
+            for k in 0..taps {
+                q += self.coeffs[k] * window[taps - 1 - k];
+            }
+            // In phase with the quadrature output: the input, delayed by the
+            // FIR's own group delay.
+            let i_val = window[HILBERT_DELAY];
+
+            // f = |arg(z[n] · conj(z[n-1]))| · fs / 2π
+            let di = i_val * self.prev_i + q * self.prev_q;
+            let dq = q * self.prev_i - i_val * self.prev_q;
+            out.push(dq.atan2(di).abs() * self.hz_per_radian);
+
+            self.prev_i = i_val;
+            self.prev_q = q;
+        }
+
+        let work_len = work.len();
+        self.tail.copy_from_slice(&work[work_len - tail_len..]);
+    }
+
+    pub fn reset(&mut self) {
+        self.bandpass_tail.fill(0.0);
+        self.tail.fill(0.0);
+        self.prev_i = 0.0;
+        self.prev_q = 0.0;
+    }
+}
+
+/// Boxcar mean over `window` samples, centred, returning one value per input.
+///
+/// The per-sample estimate ripples — badly at the low end of the band, where
+/// the Hilbert approximation is weakest: a clean 1200 Hz tone reads anywhere
+/// between 1110 and 1300 Hz sample to sample, though its mean is exact. Pixels
+/// are averaged over their own window and so come out right regardless, but
+/// anything that classifies a single sample by frequency — the VIS bits, the
+/// sync pulses — has to look at a mean or it is reading the ripple.
+pub fn smooth(freqs: &[f32], window: usize) -> Vec<f32> {
+    let window = window.max(1);
+    if freqs.is_empty() {
+        return Vec::new();
+    }
+    // Prefix sums in f64: a minute of audio is three million samples, and a
+    // running f32 total drifts long before that.
+    let mut prefix = Vec::with_capacity(freqs.len() + 1);
+    prefix.push(0.0f64);
+    for &freq in freqs {
+        prefix.push(prefix[prefix.len() - 1] + f64::from(freq));
+    }
+    let half = window / 2;
+    (0..freqs.len())
+        .map(|i| {
+            // Shrinks at the ends rather than reaching past them.
+            let from = i.saturating_sub(half);
+            let to = (i + window - half).min(freqs.len());
+            ((prefix[to] - prefix[from]) / (to - from) as f64) as f32
+        })
+        .collect()
+}
+
+/// Windowed-sinc band-pass over the SSTV band, Hamming-windowed and
+/// linear-phase, so every frequency in the band is delayed alike.
+fn design_bandpass_fir(sample_rate: u32) -> Vec<f32> {
+    let sr = sample_rate as f64;
+    let low = f64::from(BAND_LOW_HZ) / sr;
+    let high = (f64::from(BAND_HIGH_HZ) / sr).min(0.499);
+    let m = (BANDPASS_TAPS - 1) as f64;
+    let mid = m / 2.0;
+    let sinc = |x: f64| {
+        if x.abs() < 1e-9 {
+            1.0
+        } else {
+            (std::f64::consts::PI * x).sin() / (std::f64::consts::PI * x)
+        }
+    };
+    let mut coeffs = Vec::with_capacity(BANDPASS_TAPS);
+    for i in 0..BANDPASS_TAPS {
+        let n = i as f64 - mid;
+        // Difference of two low-passes is a band-pass.
+        let ideal = 2.0 * high * sinc(2.0 * high * n) - 2.0 * low * sinc(2.0 * low * n);
+        let window = 0.54 - 0.46 * (2.0 * std::f64::consts::PI * i as f64 / m).cos();
+        coeffs.push((ideal * window) as f32);
+    }
+    coeffs
+}
+
+/// Type III FIR approximating a 90° phase shift: h[n] = 2/(πn) for odd n,
+/// Blackman-windowed. Independent of sample rate, so the decoder can run at
+/// whatever rate the audio arrives in.
+fn design_hilbert_fir() -> [f32; HILBERT_TAPS] {
+    let mut coeffs = [0.0f32; HILBERT_TAPS];
+    let m = (HILBERT_TAPS - 1) as f64;
+    let mid = m / 2.0;
+    for (i, coeff) in coeffs.iter_mut().enumerate() {
+        let n = i as f64 - mid;
+        let ni = n.round() as i64;
+        if ni != 0 && ni % 2 != 0 {
+            let h = 2.0 / (std::f64::consts::PI * n);
+            let w = 0.42 - 0.5 * (2.0 * std::f64::consts::PI * i as f64 / m).cos()
+                + 0.08 * (4.0 * std::f64::consts::PI * i as f64 / m).cos();
+            *coeff = (h * w) as f32;
+        }
+    }
+    coeffs
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn tone(freq: f32, sample_rate: u32, samples: usize) -> Vec<f32> {
+        (0..samples)
+            .map(|n| (2.0 * PI * freq * n as f32 / sample_rate as f32).sin())
+            .collect()
+    }
+
+    /// Measured on the settled part of the output: the first `HILBERT_TAPS`
+    /// samples are the filter filling up.
+    fn measure(freq: f32, sample_rate: u32) -> f32 {
+        let mut demod = FreqDemod::new(sample_rate);
+        let mut out = Vec::new();
+        demod.process_into(
+            &tone(freq, sample_rate, sample_rate as usize / 10),
+            &mut out,
+        );
+        let settled = &out[HILBERT_TAPS * 2..];
+        settled.iter().sum::<f32>() / settled.len() as f32
+    }
+
+    #[test]
+    fn reads_the_tones_sstv_is_made_of() {
+        for rate in [8000u32, 11025, 44100, 48000] {
+            for freq in [1200.0f32, 1500.0, 1900.0, 2300.0] {
+                let measured = measure(freq, rate);
+                assert!(
+                    (measured - freq).abs() < 5.0,
+                    "{rate} Hz: {freq} Hz tone measured as {measured:.1} Hz",
+                );
+            }
+        }
+    }
+
+    /// Blocks are whatever size the audio pipeline hands over, and a tone that
+    /// straddles two of them must not produce a discontinuity at the seam.
+    #[test]
+    fn block_boundaries_do_not_disturb_the_estimate() {
+        let rate = 48_000;
+        let samples = tone(1900.0, rate, 9600);
+        let mut whole = FreqDemod::new(rate);
+        let mut expected = Vec::new();
+        whole.process_into(&samples, &mut expected);
+
+        let mut split = FreqDemod::new(rate);
+        let mut actual = Vec::new();
+        for chunk in samples.chunks(137) {
+            split.process_into(chunk, &mut actual);
+        }
+
+        assert_eq!(actual.len(), expected.len());
+        for (i, (a, b)) in actual.iter().zip(&expected).enumerate() {
+            assert!((a - b).abs() < 0.01, "sample {i}: {a} vs {b}");
+        }
+    }
+
+    #[test]
+    fn follows_a_step_between_tones_within_a_pixel() {
+        let rate = 48_000;
+        let mut samples = tone(1500.0, rate, 4800);
+        samples.extend(tone(2300.0, rate, 4800));
+        let mut demod = FreqDemod::new(rate);
+        let mut out = Vec::new();
+        demod.process_into(&samples, &mut out);
+
+        // Well before the step it reads black; well after it, white. The step
+        // itself takes the filter's length to pass through.
+        let before = out[4800 - 200..4800 - 100].iter().sum::<f32>() / 100.0;
+        let after = out[4800 + 200..4800 + 300].iter().sum::<f32>() / 100.0;
+        assert!(
+            (before - 1500.0).abs() < 10.0,
+            "before the step: {before:.1} Hz"
+        );
+        assert!(
+            (after - 2300.0).abs() < 10.0,
+            "after the step: {after:.1} Hz"
+        );
+    }
+}

src/decoders/trx-sstv/src/encode.rs

@@ -0,0 +1,238 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Turning an image into an SSTV signal.
+//!
+//! This exists so the decoder can be held to a picture rather than to a
+//! description of one: the tests encode a known image, decode the audio back
+//! and compare. Nothing in the receive path uses it.
+//!
+//! It is written to the same mode table the decoder reads, which makes a
+//! round-trip a test of the decoder and not of the timings — the timings are
+//! checked separately, against the published line durations, in [`crate::mode`].
+
+use crate::mode::{Channel, Segment, SstvMode, BLACK_HZ, SYNC_HZ, WHITE_HZ};
+
+/// A stretch of constant tone.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Tone {
+    pub hz: f32,
+    pub ms: f64,
+}
+
+/// Frequency for an 8-bit level: the inverse of [`crate::mode::level_from_hz`].
+pub fn hz_from_level(level: u8) -> f32 {
+    BLACK_HZ + (WHITE_HZ - BLACK_HZ) * f32::from(level) / 255.0
+}
+
+/// The tones of a VIS header announcing `vis`.
+pub fn vis_tones(vis: u8) -> Vec<Tone> {
+    let mut tones = vec![
+        Tone {
+            hz: 1900.0,
+            ms: 300.0,
+        },
+        Tone {
+            hz: 1200.0,
+            ms: 10.0,
+        },
+        Tone {
+            hz: 1900.0,
+            ms: 300.0,
+        },
+        Tone {
+            hz: 1200.0,
+            ms: 30.0,
+        }, // start bit
+    ];
+    let mut ones = 0;
+    for bit in 0..7 {
+        let set = vis & (1 << bit) != 0;
+        if set {
+            ones += 1;
+        }
+        tones.push(Tone {
+            hz: if set { 1100.0 } else { 1300.0 },
+            ms: 30.0,
+        });
+    }
+    // Even parity over the seven data bits.
+    tones.push(Tone {
+        hz: if ones % 2 == 1 { 1100.0 } else { 1300.0 },
+        ms: 30.0,
+    });
+    tones.push(Tone {
+        hz: 1200.0,
+        ms: 30.0,
+    }); // stop bit
+    tones
+}
+
+/// RGB source for the encoder: `width * height * 3` bytes.
+pub struct Frame<'a> {
+    pub width: usize,
+    pub height: usize,
+    pub rgb: &'a [u8],
+}
+
+impl Frame<'_> {
+    fn pixel(&self, x: usize, y: usize) -> (u8, u8, u8) {
+        let x = x.min(self.width.saturating_sub(1));
+        let y = y.min(self.height.saturating_sub(1));
+        let at = (y * self.width + x) * 3;
+        (self.rgb[at], self.rgb[at + 1], self.rgb[at + 2])
+    }
+
+    /// The colour components SSTV actually sends, for a pixel.
+    fn ycrcb(&self, x: usize, y: usize) -> (u8, u8, u8) {
+        let (r, g, b) = self.pixel(x, y);
+        let (r, g, b) = (f32::from(r), f32::from(g), f32::from(b));
+        let y_val = 16.0 + (0.003_906 * ((65.738 * r) + (129.057 * g) + (25.064 * b)));
+        let cr = 128.0 + (0.003_906 * ((112.439 * r) + (-94.154 * g) + (-18.285 * b)));
+        let cb = 128.0 + (0.003_906 * ((-37.945 * r) + (-74.494 * g) + (112.439 * b)));
+        (
+            y_val.clamp(0.0, 255.0) as u8,
+            cr.clamp(0.0, 255.0) as u8,
+            cb.clamp(0.0, 255.0) as u8,
+        )
+    }
+}
+
+/// Encode `frame` in `mode`, returning the tones of the whole transmission.
+pub fn encode_tones(mode: &SstvMode, frame: &Frame<'_>) -> Vec<Tone> {
+    let mut tones = vis_tones(mode.vis);
+    let per_line = usize::from(mode.lines_per_transmission);
+    let transmissions = usize::from(mode.height) / per_line;
+
+    for transmission in 0..transmissions {
+        let top = transmission * per_line;
+        for segment in mode.segments {
+            match *segment {
+                Segment::Sync(ms) => tones.push(Tone { hz: SYNC_HZ, ms }),
+                Segment::Gap(ms) => tones.push(Tone { hz: BLACK_HZ, ms }),
+                Segment::Scan { channel, ms } => {
+                    // A chroma scan carries fewer pixels than the image is
+                    // wide, and takes proportionally less time per pixel.
+                    let pixels = mode.scan_pixels(channel);
+                    let pixel_ms = ms / pixels as f64;
+                    for x in 0..pixels {
+                        let level = channel_level(mode, frame, channel, x, top, transmission);
+                        tones.push(Tone {
+                            hz: hz_from_level(level),
+                            ms: pixel_ms,
+                        });
+                    }
+                }
+            }
+        }
+    }
+    tones
+}
+
+fn channel_level(
+    mode: &SstvMode,
+    frame: &Frame<'_>,
+    channel: Channel,
+    x: usize,
+    top: usize,
+    transmission: usize,
+) -> u8 {
+    match channel {
+        Channel::Red => frame.pixel(x, top).0,
+        Channel::Green => frame.pixel(x, top).1,
+        Channel::Blue => frame.pixel(x, top).2,
+        Channel::LumaOdd => frame.ycrcb(x, top).0,
+        Channel::LumaEven => frame.ycrcb(x, top + 1).0,
+        Channel::ChromaR => chroma(mode, frame, x, top, true),
+        Channel::ChromaB => chroma(mode, frame, x, top, false),
+        // Robot 36 sends R-Y on odd transmitted lines and B-Y on even ones.
+        Channel::ChromaAlternating => chroma(mode, frame, x, top, transmission.is_multiple_of(2)),
+    }
+}
+
+/// Chroma scans are half the width of the image in the Robot modes, so each
+/// value covers two pixels; PD averages the two image lines of the pair too.
+fn chroma(mode: &SstvMode, frame: &Frame<'_>, x: usize, top: usize, want_cr: bool) -> u8 {
+    let scale = usize::from(mode.width) / mode.scan_pixels(Channel::ChromaR).max(1);
+    let x0 = x * scale;
+    let mut total = 0u32;
+    let mut count = 0u32;
+    let rows = usize::from(mode.lines_per_transmission);
+    for row in 0..rows {
+        for dx in 0..scale {
+            let (_, cr, cb) = frame.ycrcb(x0 + dx, top + row);
+            total += u32::from(if want_cr { cr } else { cb });
+            count += 1;
+        }
+    }
+    (total / count.max(1)) as u8
+}
+
+/// Render tones to audio at `sample_rate`, with continuous phase so the
+/// demodulator sees no step at a tone boundary that isn't in the signal.
+pub fn render(tones: &[Tone], sample_rate: u32) -> Vec<f32> {
+    let sr = f64::from(sample_rate);
+    let mut out =
+        Vec::with_capacity((tones.iter().map(|t| t.ms).sum::<f64>() / 1000.0 * sr) as usize);
+    let mut phase = 0.0f64;
+    // Each tone's *end* is rounded to a sample, rather than its length: a
+    // pixel of 25.5 samples rounded up on its own puts a whole line 600
+    // samples late by the end of it, which is a timing error no receiver
+    // should have to chase and no transmitter would produce.
+    let mut elapsed_ms = 0.0f64;
+    let mut emitted = 0usize;
+    for tone in tones {
+        elapsed_ms += tone.ms;
+        let end = (elapsed_ms / 1000.0 * sr).round() as usize;
+        let samples = end.saturating_sub(emitted);
+        emitted = end;
+        let step = 2.0 * std::f64::consts::PI * f64::from(tone.hz) / sr;
+        for _ in 0..samples {
+            out.push(phase.sin() as f32);
+            phase += step;
+            if phase > std::f64::consts::TAU {
+                phase -= std::f64::consts::TAU;
+            }
+        }
+    }
+    out
+}
+
+/// Encode a frame straight to audio.
+pub fn encode(mode: &SstvMode, frame: &Frame<'_>, sample_rate: u32) -> Vec<f32> {
+    render(&encode_tones(mode, frame), sample_rate)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::mode::{level_from_hz, mode_for_vis};
+
+    #[test]
+    fn levels_survive_the_trip_through_frequency() {
+        for level in [0u8, 1, 64, 128, 200, 255] {
+            assert_eq!(level_from_hz(hz_from_level(level)), level);
+        }
+    }
+
+    #[test]
+    fn a_transmission_lasts_as_long_as_the_mode_says() {
+        let mode = mode_for_vis(44).expect("Martin M1");
+        let rgb = vec![128u8; 320 * 256 * 3];
+        let frame = Frame {
+            width: 320,
+            height: 256,
+            rgb: &rgb,
+        };
+        let audio = encode(mode, &frame, 48_000);
+        // Header plus 256 lines, within a line of the published duration.
+        let header_s = 0.94;
+        let expected = header_s + mode.frame_secs();
+        let actual = audio.len() as f64 / 48_000.0;
+        assert!(
+            (actual - expected).abs() < mode.line_ms / 1000.0,
+            "encoded {actual:.2} s, expected {expected:.2} s",
+        );
+    }
+}

src/decoders/trx-sstv/src/image.rs

@@ -0,0 +1,150 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Assembling decoded lines into an image, and getting it out of the process.
+//!
+//! Rows arrive one at a time and the picture is worth looking at before it is
+//! finished, so the assembler holds a full-size RGB canvas from the start and
+//! fills it in. An unfinished frame is grey below the last decoded row rather
+//! than black, which reads as "not here yet" instead of "received as black".
+
+use std::path::{Path, PathBuf};
+
+use base64::Engine;
+
+/// Value the canvas starts at: mid-grey, for rows not yet received.
+const UNWRITTEN: u8 = 96;
+
+pub struct ImageCanvas {
+    width: usize,
+    height: usize,
+    rgb: Vec<u8>,
+    /// Highest row index written, plus one.
+    filled_rows: usize,
+}
+
+impl ImageCanvas {
+    pub fn new(width: usize, height: usize) -> Self {
+        Self {
+            width,
+            height,
+            rgb: vec![UNWRITTEN; width * height * 3],
+            filled_rows: 0,
+        }
+    }
+
+    pub fn width(&self) -> usize {
+        self.width
+    }
+
+    pub fn height(&self) -> usize {
+        self.height
+    }
+
+    /// Rows written so far.
+    pub fn filled_rows(&self) -> usize {
+        self.filled_rows
+    }
+
+    /// Write one row of RGB triples. Rows past the bottom of the image are
+    /// dropped: a transmission that runs long is not a reason to grow.
+    pub fn put_row(&mut self, y: usize, row: &[u8]) {
+        if y >= self.height {
+            return;
+        }
+        let at = y * self.width * 3;
+        let take = row.len().min(self.width * 3);
+        self.rgb[at..at + take].copy_from_slice(&row[..take]);
+        self.filled_rows = self.filled_rows.max(y + 1);
+    }
+
+    pub fn row(&self, y: usize) -> Option<&[u8]> {
+        if y >= self.height {
+            return None;
+        }
+        let at = y * self.width * 3;
+        Some(&self.rgb[at..at + self.width * 3])
+    }
+
+    pub fn rgb(&self) -> &[u8] {
+        &self.rgb
+    }
+
+    /// Encode the canvas as a PNG.
+    pub fn to_png(&self) -> Result<Vec<u8>, String> {
+        let mut out = Vec::new();
+        {
+            let mut encoder = png::Encoder::new(&mut out, self.width as u32, self.height as u32);
+            encoder.set_color(png::ColorType::Rgb);
+            encoder.set_depth(png::BitDepth::Eight);
+            let mut writer = encoder
+                .write_header()
+                .map_err(|e| format!("PNG header: {e}"))?;
+            writer
+                .write_image_data(&self.rgb)
+                .map_err(|e| format!("PNG data: {e}"))?;
+        }
+        Ok(out)
+    }
+
+    /// The PNG, base64-encoded for the journey to a browser.
+    pub fn to_png_base64(&self) -> Result<String, String> {
+        Ok(base64::engine::general_purpose::STANDARD.encode(self.to_png()?))
+    }
+
+    /// Write the PNG into `dir`, named for when and where it was received.
+    pub fn save_png(
+        &self,
+        dir: &Path,
+        freq_hz: u64,
+        mode_name: &str,
+        stamp: &str,
+    ) -> Result<PathBuf, String> {
+        std::fs::create_dir_all(dir).map_err(|e| format!("create {}: {e}", dir.display()))?;
+        let slug: String = mode_name
+            .chars()
+            .map(|c| if c.is_ascii_alphanumeric() { c } else { '-' })
+            .collect();
+        let path = dir.join(format!("SSTV_{stamp}_{freq_hz}_{slug}.png"));
+        std::fs::write(&path, self.to_png()?)
+            .map_err(|e| format!("write {}: {e}", path.display()))?;
+        Ok(path)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn rows_land_where_they_are_put_and_the_rest_stays_unwritten() {
+        let mut canvas = ImageCanvas::new(4, 3);
+        canvas.put_row(1, &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]);
+        assert_eq!(canvas.row(1).unwrap()[0..3], [1, 2, 3]);
+        assert_eq!(canvas.row(0).unwrap()[0], UNWRITTEN);
+        assert_eq!(canvas.filled_rows(), 2);
+    }
+
+    #[test]
+    fn a_row_past_the_bottom_is_dropped_rather_than_growing_the_image() {
+        let mut canvas = ImageCanvas::new(2, 2);
+        canvas.put_row(9, &[1, 2, 3, 4, 5, 6]);
+        assert_eq!(canvas.filled_rows(), 0);
+        assert_eq!(canvas.rgb().len(), 2 * 2 * 3);
+    }
+
+    #[test]
+    fn encodes_a_png_a_decoder_can_read_back() {
+        let mut canvas = ImageCanvas::new(2, 2);
+        canvas.put_row(0, &[255, 0, 0, 0, 255, 0]);
+        let png_bytes = canvas.to_png().expect("png");
+        let decoder = png::Decoder::new(png_bytes.as_slice());
+        let mut reader = decoder.read_info().expect("png info");
+        let mut buf = vec![0; reader.output_buffer_size()];
+        let info = reader.next_frame(&mut buf).expect("png frame");
+        assert_eq!((info.width, info.height), (2, 2));
+        assert_eq!(&buf[0..6], &[255, 0, 0, 0, 255, 0]);
+        assert!(!canvas.to_png_base64().expect("base64").is_empty());
+    }
+}

src/decoders/trx-sstv/src/lib.rs

@@ -0,0 +1,36 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! SSTV (Slow-Scan Television) decoder.
+//!
+//! Pure Rust, covering Martin, Scottie, Robot, PD and Wraase SC2-180, with the
+//! mode taken from the VIS header that precedes every transmission. Rows are
+//! emitted as they arrive so a picture can be watched building up.
+//!
+//! ```no_run
+//! use trx_sstv::{SstvConfig, SstvDecoder, SstvEvent};
+//!
+//! let mut decoder = SstvDecoder::new(48_000, SstvConfig::default());
+//! # let audio: Vec<f32> = Vec::new();
+//! for event in decoder.process_samples(&audio) {
+//!     match event {
+//!         SstvEvent::Started { mode, .. } => println!("receiving {mode}"),
+//!         SstvEvent::Row { line, .. } => println!("line {line}"),
+//!         SstvEvent::Complete(image) => println!("{} lines", image.lines),
+//!     }
+//! }
+//! ```
+
+pub mod config;
+pub mod decoder;
+pub mod demod;
+pub mod encode;
+pub mod image;
+pub mod mode;
+pub mod vis;
+
+pub use config::SstvConfig;
+pub use decoder::{SstvDecoder, SstvEvent, SstvImage};
+pub use image::ImageCanvas;
+pub use mode::{mode_for_vis, SstvMode, MODES};

src/decoders/trx-sstv/src/mode.rs

@@ -0,0 +1,615 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! SSTV mode table: what a VIS code means in timings, geometry and colour.
+//!
+//! Every mode transmits a line as a sequence of *segments* — a sync pulse, a
+//! porch or separator at a fixed tone, and one scan per colour channel. The
+//! decoder needs only the segment layout and the offset of each scan within
+//! the line, so that is what a [`SstvMode`] is: a list of segments plus the
+//! rules for turning the scans back into pixels.
+//!
+//! Timings follow the published mode specifications (JL Barber, N7CXI,
+//! "Proposal for SSTV Mode Specifications", 2000), which is the same table
+//! MMSSTV, QSSTV and slowrx work from.
+
+/// Tone that marks a line boundary, in Hz.
+pub const SYNC_HZ: f32 = 1200.0;
+/// Tone for black, in Hz.
+pub const BLACK_HZ: f32 = 1500.0;
+/// Tone for white, in Hz.
+pub const WHITE_HZ: f32 = 2300.0;
+
+/// What a scan segment carries.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Channel {
+    Red,
+    Green,
+    Blue,
+    /// Luminance for the odd (first) image line of the pair.
+    LumaOdd,
+    /// Luminance for the even (second) image line of a PD pair.
+    LumaEven,
+    /// R-Y chrominance.
+    ChromaR,
+    /// B-Y chrominance.
+    ChromaB,
+    /// Robot 36 alternates R-Y and B-Y between transmitted lines: odd lines
+    /// carry R-Y, even lines B-Y, and each is held over both.
+    ChromaAlternating,
+}
+
+/// One piece of a transmitted line.
+#[derive(Debug, Clone, Copy)]
+pub enum Segment {
+    /// Sync pulse at [`SYNC_HZ`].
+    Sync(f64),
+    /// Porch, separator or gap at a fixed tone; the tone itself is not decoded.
+    Gap(f64),
+    /// A scan carrying pixels for one channel.
+    Scan { channel: Channel, ms: f64 },
+}
+
+impl Segment {
+    pub fn duration_ms(&self) -> f64 {
+        match *self {
+            Segment::Sync(ms) | Segment::Gap(ms) => ms,
+            Segment::Scan { ms, .. } => ms,
+        }
+    }
+}
+
+/// How the scans of a line become pixels.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ColorModel {
+    /// Scans are red, green and blue directly (Martin, Scottie, Wraase).
+    Rgb,
+    /// Y plus one alternating chroma channel per line (Robot 36).
+    YCrCbAlternating,
+    /// Y, R-Y and B-Y in every line (Robot 72).
+    YCrCb,
+    /// Two image lines per transmitted line: Y odd, R-Y, B-Y, Y even (PD).
+    YCrCbPaired,
+}
+
+/// A decodable SSTV mode.
+#[derive(Debug, Clone)]
+pub struct SstvMode {
+    /// VIS code as sent in the header.
+    pub vis: u8,
+    /// Human-readable name, e.g. "Martin M1".
+    pub name: &'static str,
+    /// Pixels across.
+    pub width: u16,
+    /// Image lines in a full frame.
+    pub height: u16,
+    /// Transmitted line duration in milliseconds.
+    pub line_ms: f64,
+    /// Segments in transmission order.
+    pub segments: &'static [Segment],
+    pub color: ColorModel,
+    /// Image lines produced by one transmitted line (2 for PD, otherwise 1).
+    pub lines_per_transmission: u16,
+    /// Offset from the start of a line to the leading edge of its sync pulse.
+    /// Zero for most modes; Scottie sends the sync in the middle of the line,
+    /// so a line detected at its sync starts before it.
+    pub sync_offset_ms: f64,
+}
+
+impl SstvMode {
+    /// Total of every segment, which must equal [`SstvMode::line_ms`].
+    pub fn segments_ms(&self) -> f64 {
+        self.segments.iter().map(Segment::duration_ms).sum()
+    }
+
+    /// Start offset, in milliseconds from the line start, of each scan.
+    pub fn scans(&self) -> Vec<(Channel, f64, f64)> {
+        let mut out = Vec::new();
+        let mut at = 0.0;
+        for segment in self.segments {
+            if let Segment::Scan { channel, ms } = *segment {
+                out.push((channel, at, ms));
+            }
+            at += segment.duration_ms();
+        }
+        out
+    }
+
+    /// Pixels carried by a scan of this channel.
+    ///
+    /// Chroma is sent at half the width in the Robot modes — the eye takes
+    /// colour more coarsely than brightness, and the saving is what makes 36
+    /// seconds possible. PD sends chroma at full width and saves its time by
+    /// sharing one pair of chroma scans between two image lines instead.
+    pub fn scan_pixels(&self, channel: Channel) -> usize {
+        let width = usize::from(self.width);
+        match channel {
+            Channel::ChromaR | Channel::ChromaB | Channel::ChromaAlternating
+                if self.color != ColorModel::YCrCbPaired =>
+            {
+                width / 2
+            }
+            _ => width,
+        }
+    }
+
+    /// Seconds a full frame takes to send.
+    pub fn frame_secs(&self) -> f64 {
+        self.line_ms * f64::from(self.height) / f64::from(self.lines_per_transmission) / 1000.0
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Martin — sync, porch, then green, blue, red, each followed by a separator.
+// ---------------------------------------------------------------------------
+
+const MARTIN_M1: &[Segment] = &[
+    Segment::Sync(4.862),
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 146.432,
+    },
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 146.432,
+    },
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 146.432,
+    },
+    Segment::Gap(0.572),
+];
+
+const MARTIN_M2: &[Segment] = &[
+    Segment::Sync(4.862),
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 73.216,
+    },
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 73.216,
+    },
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 73.216,
+    },
+    Segment::Gap(0.572),
+];
+
+// ---------------------------------------------------------------------------
+// Scottie — the sync pulse sits between the blue and red scans, so a line
+// starts one separator before the green scan and the sync of the *previous*
+// line is what marks it.
+// ---------------------------------------------------------------------------
+
+const SCOTTIE_S1: &[Segment] = &[
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 138.240,
+    },
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 138.240,
+    },
+    Segment::Sync(9.0),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 138.240,
+    },
+];
+
+const SCOTTIE_S2: &[Segment] = &[
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 88.064,
+    },
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 88.064,
+    },
+    Segment::Sync(9.0),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 88.064,
+    },
+];
+
+const SCOTTIE_DX: &[Segment] = &[
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 345.6,
+    },
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 345.6,
+    },
+    Segment::Sync(9.0),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 345.6,
+    },
+];
+
+/// Scottie's sync arrives after the green and blue scans: 1.5 + 138.24 + 1.5 +
+/// 138.24 for S1, and the equivalent for the others.
+const fn scottie_sync_offset(scan_ms: f64) -> f64 {
+    1.5 + scan_ms + 1.5 + scan_ms
+}
+
+// ---------------------------------------------------------------------------
+// Robot — luminance plus chrominance, the chroma scans at half the width.
+// ---------------------------------------------------------------------------
+
+const ROBOT_36: &[Segment] = &[
+    Segment::Sync(9.0),
+    Segment::Gap(3.0),
+    Segment::Scan {
+        channel: Channel::LumaOdd,
+        ms: 88.0,
+    },
+    Segment::Gap(4.5),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::ChromaAlternating,
+        ms: 44.0,
+    },
+];
+
+const ROBOT_72: &[Segment] = &[
+    Segment::Sync(9.0),
+    Segment::Gap(3.0),
+    Segment::Scan {
+        channel: Channel::LumaOdd,
+        ms: 138.0,
+    },
+    Segment::Gap(4.5),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::ChromaR,
+        ms: 69.0,
+    },
+    Segment::Gap(4.5),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::ChromaB,
+        ms: 69.0,
+    },
+];
+
+// ---------------------------------------------------------------------------
+// PD — one transmitted line carries two image lines: the luminance of both,
+// with a single pair of chroma scans shared between them.
+// ---------------------------------------------------------------------------
+
+macro_rules! pd_segments {
+    ($name:ident, $scan:expr) => {
+        const $name: &[Segment] = &[
+            Segment::Sync(20.0),
+            Segment::Gap(2.08),
+            Segment::Scan {
+                channel: Channel::LumaOdd,
+                ms: $scan,
+            },
+            Segment::Scan {
+                channel: Channel::ChromaR,
+                ms: $scan,
+            },
+            Segment::Scan {
+                channel: Channel::ChromaB,
+                ms: $scan,
+            },
+            Segment::Scan {
+                channel: Channel::LumaEven,
+                ms: $scan,
+            },
+        ];
+    };
+}
+
+pd_segments!(PD_50, 91.520);
+pd_segments!(PD_90, 170.240);
+pd_segments!(PD_120, 121.600);
+pd_segments!(PD_160, 195.584);
+pd_segments!(PD_180, 183.040);
+pd_segments!(PD_240, 244.672);
+pd_segments!(PD_290, 228.800);
+
+// ---------------------------------------------------------------------------
+// Wraase SC2-180 — red, green, blue in that order after one porch.
+// ---------------------------------------------------------------------------
+
+const WRAASE_SC2_180: &[Segment] = &[
+    Segment::Sync(5.5225),
+    Segment::Gap(0.5),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 235.0,
+    },
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 235.0,
+    },
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 235.0,
+    },
+];
+
+/// Every mode this decoder knows, in VIS order.
+pub static MODES: &[SstvMode] = &[
+    SstvMode {
+        vis: 8,
+        name: "Robot 36",
+        width: 320,
+        height: 240,
+        line_ms: 150.0,
+        segments: ROBOT_36,
+        color: ColorModel::YCrCbAlternating,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 12,
+        name: "Robot 72",
+        width: 320,
+        height: 240,
+        line_ms: 300.0,
+        segments: ROBOT_72,
+        color: ColorModel::YCrCb,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 40,
+        name: "Martin M2",
+        width: 320,
+        height: 256,
+        line_ms: 226.798,
+        segments: MARTIN_M2,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 44,
+        name: "Martin M1",
+        width: 320,
+        height: 256,
+        line_ms: 446.446,
+        segments: MARTIN_M1,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 55,
+        name: "Wraase SC2-180",
+        width: 320,
+        height: 256,
+        line_ms: 711.0225,
+        segments: WRAASE_SC2_180,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 56,
+        name: "Scottie S2",
+        width: 320,
+        height: 256,
+        line_ms: 277.692,
+        segments: SCOTTIE_S2,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: scottie_sync_offset(88.064),
+    },
+    SstvMode {
+        vis: 60,
+        name: "Scottie S1",
+        width: 320,
+        height: 256,
+        line_ms: 428.22,
+        segments: SCOTTIE_S1,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: scottie_sync_offset(138.240),
+    },
+    SstvMode {
+        vis: 76,
+        name: "Scottie DX",
+        width: 320,
+        height: 256,
+        line_ms: 1050.3,
+        segments: SCOTTIE_DX,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: scottie_sync_offset(345.6),
+    },
+    SstvMode {
+        vis: 93,
+        name: "PD50",
+        width: 320,
+        height: 256,
+        line_ms: 388.16,
+        segments: PD_50,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 94,
+        name: "PD290",
+        width: 800,
+        height: 616,
+        line_ms: 937.28,
+        segments: PD_290,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 95,
+        name: "PD120",
+        width: 640,
+        height: 496,
+        line_ms: 508.48,
+        segments: PD_120,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 96,
+        name: "PD180",
+        width: 640,
+        height: 496,
+        line_ms: 754.24,
+        segments: PD_180,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 97,
+        name: "PD240",
+        width: 640,
+        height: 496,
+        line_ms: 1000.768,
+        segments: PD_240,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 98,
+        name: "PD160",
+        width: 512,
+        height: 400,
+        line_ms: 804.416,
+        segments: PD_160,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 99,
+        name: "PD90",
+        width: 320,
+        height: 256,
+        line_ms: 703.04,
+        segments: PD_90,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+];
+
+/// Look a mode up by the VIS code that announced it.
+pub fn mode_for_vis(vis: u8) -> Option<&'static SstvMode> {
+    MODES.iter().find(|mode| mode.vis == vis)
+}
+
+/// Map an instantaneous frequency to an 8-bit level: 1500 Hz is black, 2300 Hz
+/// white. Frequencies outside the band clamp rather than wrap, so a sync pulse
+/// that lands inside a scan reads as black instead of as bright noise.
+pub fn level_from_hz(hz: f32) -> u8 {
+    let level = (hz - BLACK_HZ) * (255.0 / (WHITE_HZ - BLACK_HZ));
+    level.clamp(0.0, 255.0).round() as u8
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // The segment list and the published line time are two statements of the
+    // same fact, entered by hand from the specification. If a digit is wrong in
+    // one it is unlikely to be wrong identically in the other.
+    #[test]
+    fn segments_add_up_to_the_published_line_time() {
+        for mode in MODES {
+            let sum = mode.segments_ms();
+            assert!(
+                (sum - mode.line_ms).abs() < 0.001,
+                "{}: segments total {:.4} ms, line time says {:.4} ms",
+                mode.name,
+                sum,
+                mode.line_ms,
+            );
+        }
+    }
+
+    #[test]
+    fn vis_codes_are_unique_and_resolvable() {
+        for mode in MODES {
+            assert_eq!(mode_for_vis(mode.vis).map(|m| m.name), Some(mode.name));
+        }
+        let mut codes: Vec<u8> = MODES.iter().map(|m| m.vis).collect();
+        codes.sort_unstable();
+        let count = codes.len();
+        codes.dedup();
+        assert_eq!(codes.len(), count, "two modes claim the same VIS code");
+    }
+
+    #[test]
+    fn every_mode_scans_enough_channels_for_its_colour_model() {
+        for mode in MODES {
+            let scans = mode.scans();
+            let expected = match mode.color {
+                ColorModel::Rgb => 3,
+                ColorModel::YCrCbAlternating => 2,
+                ColorModel::YCrCb => 3,
+                ColorModel::YCrCbPaired => 4,
+            };
+            assert_eq!(
+                scans.len(),
+                expected,
+                "{} has {} scans",
+                mode.name,
+                scans.len()
+            );
+        }
+    }
+
+    // Frame durations are what operators know these modes by — the number in
+    // the name is the number of seconds.
+    #[test]
+    fn frame_durations_match_the_names() {
+        for (vis, secs) in [(8u8, 36.0), (12, 72.0), (93, 50.0), (99, 90.0), (95, 126.0)] {
+            let mode = mode_for_vis(vis).expect("mode in table");
+            let actual = mode.frame_secs();
+            assert!(
+                (actual - secs).abs() < 1.5,
+                "{} takes {:.1} s, expected about {:.0} s",
+                mode.name,
+                actual,
+                secs,
+            );
+        }
+    }
+
+    #[test]
+    fn levels_span_black_to_white_and_clamp_outside() {
+        assert_eq!(level_from_hz(BLACK_HZ), 0);
+        assert_eq!(level_from_hz(WHITE_HZ), 255);
+        assert_eq!(level_from_hz(1900.0), 128);
+        assert_eq!(level_from_hz(SYNC_HZ), 0, "a sync pulse must read as black");
+        assert_eq!(level_from_hz(3000.0), 255);
+    }
+}

src/decoders/trx-sstv/src/vis.rs

@@ -0,0 +1,236 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! VIS header detection.
+//!
+//! Every transmission announces its mode in a fixed preamble:
+//!
+//! | Part | Tone | Duration |
+//! |------|------|----------|
+//! | Leader | 1900 Hz | 300 ms |
+//! | Break | 1200 Hz | 10 ms |
+//! | Leader | 1900 Hz | 300 ms |
+//! | Start bit | 1200 Hz | 30 ms |
+//! | 7 data bits, LSB first | 1100 Hz = 1, 1300 Hz = 0 | 30 ms each |
+//! | Even parity | as above | 30 ms |
+//! | Stop bit | 1200 Hz | 30 ms |
+//!
+//! The detector looks for the start bit standing behind a leader, reads the
+//! eight bits that follow, and checks the parity. Parity is the only integrity
+//! check the header has, so a code that fails it is discarded rather than
+//! guessed at — decoding 114 seconds of Martin M1 as Scottie DX produces a
+//! convincing-looking image of nothing.
+
+/// Tone durations, in milliseconds.
+const BIT_MS: f64 = 30.0;
+const LEADER_MS: f64 = 300.0;
+
+/// How far a tone may sit from its nominal frequency and still be recognised.
+/// Wide enough for a rig tuned a little off, narrow enough that 1100, 1200,
+/// 1300 and 1900 Hz stay distinct.
+const TONE_TOLERANCE_HZ: f32 = 60.0;
+
+const LEADER_HZ: f32 = 1900.0;
+const START_HZ: f32 = 1200.0;
+const ONE_HZ: f32 = 1100.0;
+const ZERO_HZ: f32 = 1300.0;
+
+/// A VIS header found in the stream.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct VisHit {
+    /// The code, which names the mode.
+    pub code: u8,
+    /// Index just past the stop bit: where the image itself begins.
+    pub image_start: usize,
+}
+
+fn near(freq: f32, target: f32) -> bool {
+    (freq - target).abs() <= TONE_TOLERANCE_HZ
+}
+
+/// Mean frequency over the middle 60% of a bit cell, which keeps the filter's
+/// transitions at either edge out of the measurement.
+fn bit_frequency(freqs: &[f32], start: f64, samples_per_bit: f64) -> Option<f32> {
+    let from = (start + samples_per_bit * 0.2).round() as usize;
+    let to = (start + samples_per_bit * 0.8).round() as usize;
+    if to <= from || to > freqs.len() {
+        return None;
+    }
+    let window = &freqs[from..to];
+    Some(window.iter().sum::<f32>() / window.len() as f32)
+}
+
+/// Search `freqs` for a VIS header, starting at `from`.
+///
+/// Returns the first header whose parity checks out. `freqs` is instantaneous
+/// frequency in Hz, one entry per audio sample.
+pub fn find_vis(freqs: &[f32], sample_rate: u32, from: usize) -> Option<VisHit> {
+    let sr = f64::from(sample_rate);
+    // Header tones are 10 ms at the shortest, so a millisecond of averaging
+    // costs nothing and takes the demodulator's ripple — ±95 Hz at 1200 Hz —
+    // out of tones that are 100 Hz apart.
+    let smoothed = crate::demod::smooth(freqs, (sr / 1000.0).round() as usize);
+    let freqs = smoothed.as_slice();
+    let samples_per_bit = BIT_MS / 1000.0 * sr;
+    let leader_samples = (LEADER_MS / 1000.0 * sr) as usize;
+    // The start bit must be at least this long to be one.
+    let min_start_run = (samples_per_bit * 0.7) as usize;
+
+    // A leader has to precede the start bit. Half of one is enough evidence,
+    // and asking for less than the full 300 ms means the search still works on
+    // a buffer that begins part-way through the header.
+    let leader_needed = leader_samples / 2;
+
+    // The bits themselves may run to the very end of what has arrived so far;
+    // reading them is what decides whether there is enough, not this bound.
+    let mut i = from.max(leader_needed);
+    while i < freqs.len() {
+        if !near(freqs[i], START_HZ) {
+            i += 1;
+            continue;
+        }
+        // Measure the run of start tone.
+        let mut run = 0usize;
+        while i + run < freqs.len() && near(freqs[i + run], START_HZ) {
+            run += 1;
+        }
+        if run < min_start_run {
+            i += run.max(1);
+            continue;
+        }
+
+        // What came before it: the leader. Sampled rather than scanned in
+        // full, since only its identity matters, not its exact length.
+        let leader_from = i - leader_needed;
+        let leader_hits = freqs[leader_from..i]
+            .iter()
+            .step_by(16)
+            .filter(|&&f| near(f, LEADER_HZ))
+            .count();
+        let leader_total = freqs[leader_from..i].iter().step_by(16).count();
+        if leader_total == 0 || (leader_hits as f64) < 0.7 * leader_total as f64 {
+            i += run;
+            continue;
+        }
+
+        // Bits follow the start bit, which the run just measured. Use the run's
+        // own end rather than a nominal offset, so a start bit stretched or
+        // clipped by the filter does not shift every bit after it.
+        let bits_start = (i + run) as f64;
+        let mut bits = [false; 8];
+        let mut readable = true;
+        for (index, bit) in bits.iter_mut().enumerate() {
+            let at = bits_start + samples_per_bit * index as f64;
+            match bit_frequency(freqs, at, samples_per_bit) {
+                Some(freq) if near(freq, ONE_HZ) => *bit = true,
+                Some(freq) if near(freq, ZERO_HZ) => *bit = false,
+                _ => {
+                    readable = false;
+                    break;
+                }
+            }
+        }
+        if !readable {
+            i += run;
+            continue;
+        }
+
+        // Seven data bits, LSB first, then even parity over them.
+        let code = bits[..7]
+            .iter()
+            .enumerate()
+            .fold(0u8, |acc, (index, &set)| acc | (u8::from(set) << index));
+        let ones = bits[..7].iter().filter(|&&b| b).count() + usize::from(bits[7]);
+        if ones % 2 != 0 {
+            i += run;
+            continue;
+        }
+
+        // Past the stop bit is the image.
+        let image_start = (bits_start + samples_per_bit * 9.0).round() as usize;
+        return Some(VisHit { code, image_start });
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::encode::{vis_tones, Tone};
+
+    fn freqs_from_tones(tones: &[Tone], sample_rate: u32) -> Vec<f32> {
+        let mut out = Vec::new();
+        for tone in tones {
+            let samples = (tone.ms / 1000.0 * f64::from(sample_rate)).round() as usize;
+            out.extend(std::iter::repeat_n(tone.hz, samples));
+        }
+        out
+    }
+
+    #[test]
+    fn reads_every_code_the_mode_table_knows() {
+        for mode in crate::mode::MODES {
+            let freqs = freqs_from_tones(&vis_tones(mode.vis), 48_000);
+            let hit = find_vis(&freqs, 48_000, 0)
+                .unwrap_or_else(|| panic!("{} header not found", mode.name));
+            assert_eq!(
+                hit.code, mode.vis,
+                "{} decoded as VIS {}",
+                mode.name, hit.code
+            );
+        }
+    }
+
+    #[test]
+    fn the_image_starts_after_the_stop_bit() {
+        let sample_rate = 48_000;
+        let freqs = freqs_from_tones(&vis_tones(44), sample_rate);
+        let hit = find_vis(&freqs, sample_rate, 0).expect("header");
+        // Header is 300 + 10 + 300 ms of leader and break, then ten 30 ms bits.
+        let expected = ((300.0 + 10.0 + 300.0 + 300.0) / 1000.0 * f64::from(sample_rate)) as usize;
+        let slack = sample_rate as usize / 100; // 10 ms
+        assert!(
+            hit.image_start.abs_diff(expected) < slack,
+            "image starts at {}, expected about {expected}",
+            hit.image_start,
+        );
+    }
+
+    #[test]
+    fn a_header_with_broken_parity_is_not_a_header() {
+        let sample_rate = 48_000;
+        let mut tones = vis_tones(44);
+        // Flip the parity bit alone: seven data bits still say Martin M1, but
+        // nothing now vouches for them.
+        let parity = tones.len() - 2;
+        tones[parity].hz = if tones[parity].hz == ONE_HZ {
+            ZERO_HZ
+        } else {
+            ONE_HZ
+        };
+        let freqs = freqs_from_tones(&tones, sample_rate);
+        assert_eq!(find_vis(&freqs, sample_rate, 0), None);
+    }
+
+    #[test]
+    fn tones_without_a_leader_are_not_a_header() {
+        let sample_rate = 48_000;
+        let mut tones = vis_tones(44);
+        // Same bits, but the leader before them is a pixel-band tone — which is
+        // what a passing image looks like.
+        tones[0].hz = 2000.0;
+        tones[2].hz = 2000.0;
+        let freqs = freqs_from_tones(&tones, sample_rate);
+        assert_eq!(find_vis(&freqs, sample_rate, 0), None);
+    }
+
+    #[test]
+    fn a_header_part_way_into_the_buffer_is_still_found() {
+        let sample_rate = 48_000;
+        let mut freqs = vec![1750.0f32; sample_rate as usize]; // a second of picture
+        freqs.extend(freqs_from_tones(&vis_tones(60), sample_rate));
+        let hit = find_vis(&freqs, sample_rate, 0).expect("header");
+        assert_eq!(hit.code, 60);
+    }
+}

src/decoders/trx-sstv/tests/round_trip.rs

@@ -0,0 +1,384 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Decode what was encoded, and compare the pictures.
+//!
+//! A decoder for a picture format can only really be tested against a picture.
+//! These tests build a test card, transmit it in each mode through the
+//! encoder, and hold the decoder to what comes back — pixel by pixel, with a
+//! tolerance that accounts for the round trip through frequency and, for the
+//! colour modes, through a chroma channel at half the width.
+//!
+//! What this does not test is the timing table itself: the encoder reads the
+//! same numbers as the decoder, so a wrong line duration would cancel out.
+//! That is checked in `mode.rs` against the published line times instead.
+
+use trx_sstv::encode::{encode, Frame};
+use trx_sstv::mode::mode_for_vis;
+use trx_sstv::{SstvConfig, SstvDecoder, SstvEvent, SstvImage};
+
+const SAMPLE_RATE: u32 = 48_000;
+
+/// A test card with something for every part of the decoder to get wrong:
+/// vertical colour bars catch channels swapped or shifted, the horizontal
+/// gradient catches a line-timing drift, and the corner blocks catch a picture
+/// that arrives upside down or mirrored.
+fn test_card(width: usize, height: usize) -> Vec<u8> {
+    let mut rgb = vec![0u8; width * height * 3];
+    let bars: [(u8, u8, u8); 8] = [
+        (255, 255, 255),
+        (255, 255, 0),
+        (0, 255, 255),
+        (0, 255, 0),
+        (255, 0, 255),
+        (255, 0, 0),
+        (0, 0, 255),
+        (0, 0, 0),
+    ];
+    for y in 0..height {
+        for x in 0..width {
+            let at = (y * width + x) * 3;
+            let (r, g, b) = if y < height / 2 {
+                bars[x * bars.len() / width]
+            } else {
+                let ramp = (x * 255 / width.max(1)) as u8;
+                let down = (y * 255 / height.max(1)) as u8;
+                (ramp, down, 255 - ramp)
+            };
+            rgb[at] = r;
+            rgb[at + 1] = g;
+            rgb[at + 2] = b;
+        }
+    }
+    // Corner marks: red top-left, blue bottom-right.
+    for y in 0..height.min(8) {
+        for x in 0..width.min(8) {
+            let at = (y * width + x) * 3;
+            rgb[at] = 255;
+            rgb[at + 1] = 0;
+            rgb[at + 2] = 0;
+        }
+    }
+    for y in height.saturating_sub(8)..height {
+        for x in width.saturating_sub(8)..width {
+            let at = (y * width + x) * 3;
+            rgb[at] = 0;
+            rgb[at + 1] = 0;
+            rgb[at + 2] = 255;
+        }
+    }
+    rgb
+}
+
+/// Run audio through the decoder in blocks the size a sound card delivers.
+///
+/// A little silence is fed after the signal, as a receiver that keeps
+/// listening supplies: the demodulator is a filter, so the last millisecond of
+/// any transmission needs the samples after it before it can be read.
+fn decode(audio: &[f32]) -> (Vec<SstvImage>, usize) {
+    let mut tail = audio.to_vec();
+    tail.extend(std::iter::repeat_n(0.0, SAMPLE_RATE as usize / 20));
+    let audio = tail.as_slice();
+
+    let mut decoder = SstvDecoder::new(SAMPLE_RATE, SstvConfig::default());
+    let mut images = Vec::new();
+    let mut rows = 0;
+    for block in audio.chunks(1024) {
+        for event in decoder.process_samples(block) {
+            match event {
+                SstvEvent::Row { .. } => rows += 1,
+                SstvEvent::Complete(image) => images.push(image),
+                SstvEvent::Started { .. } => {}
+            }
+        }
+    }
+    (images, rows)
+}
+
+/// Mean absolute error per colour channel between two same-sized images.
+fn mean_error(a: &[u8], b: &[u8]) -> f64 {
+    assert_eq!(a.len(), b.len());
+    let total: u64 = a
+        .iter()
+        .zip(b)
+        .map(|(x, y)| u64::from(x.abs_diff(*y)))
+        .sum();
+    total as f64 / a.len() as f64
+}
+
+/// Error over the part of the picture away from channel edges, where a decoder
+/// that is a pixel out on a hard colour boundary would otherwise dominate.
+fn interior_error(mode_width: usize, height: usize, sent: &[u8], got: &[u8]) -> f64 {
+    let mut total = 0u64;
+    let mut count = 0u64;
+    for y in 2..height.saturating_sub(2) {
+        for x in 4..mode_width.saturating_sub(4) {
+            // Skip the columns where the bars change, which is where a
+            // half-pixel timing difference shows up as a whole-colour error.
+            if x % (mode_width / 8) < 3 {
+                continue;
+            }
+            let at = (y * mode_width + x) * 3;
+            for channel in 0..3 {
+                total += u64::from(sent[at + channel].abs_diff(got[at + channel]));
+                count += 1;
+            }
+        }
+    }
+    total as f64 / count.max(1) as f64
+}
+
+fn round_trip(vis: u8, tolerance: f64) {
+    let mode = mode_for_vis(vis).expect("mode in table");
+    let width = usize::from(mode.width);
+    let height = usize::from(mode.height);
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let audio = encode(mode, &frame, SAMPLE_RATE);
+
+    let (images, rows) = decode(&audio);
+    assert_eq!(
+        images.len(),
+        1,
+        "{}: expected one picture, got {}",
+        mode.name,
+        images.len()
+    );
+    let image = &images[0];
+    assert!(
+        image.complete,
+        "{}: reception did not reach the bottom",
+        mode.name
+    );
+    assert_eq!(image.mode, mode.name);
+    assert_eq!(
+        image.lines, mode.height,
+        "{}: {} of {} lines",
+        mode.name, image.lines, mode.height
+    );
+    assert_eq!(
+        rows, height,
+        "{}: emitted {rows} rows for {height} lines",
+        mode.name
+    );
+
+    let error = interior_error(width, height, &sent, &image.rgb);
+    assert!(
+        error < tolerance,
+        "{}: mean error {error:.1} levels, tolerance {tolerance:.1}",
+        mode.name,
+    );
+}
+
+#[test]
+fn martin_m1_round_trips() {
+    round_trip(44, 6.0);
+}
+
+#[test]
+fn martin_m2_round_trips() {
+    round_trip(40, 8.0);
+}
+
+#[test]
+fn scottie_s1_round_trips() {
+    round_trip(60, 6.0);
+}
+
+#[test]
+fn scottie_s2_round_trips() {
+    round_trip(56, 8.0);
+}
+
+#[test]
+fn wraase_sc2_180_round_trips() {
+    round_trip(55, 6.0);
+}
+
+// The colour-difference modes lose chroma resolution by design, so the bars
+// bleed into one another at their edges; the tolerance is on the interior.
+#[test]
+fn robot_72_round_trips() {
+    round_trip(12, 14.0);
+}
+
+#[test]
+fn robot_36_round_trips() {
+    // One chroma channel per line, the other carried over from the line
+    // before, so alternate lines are a line stale in one channel.
+    round_trip(8, 26.0);
+}
+
+#[test]
+fn pd90_round_trips() {
+    round_trip(99, 14.0);
+}
+
+#[test]
+fn pd120_round_trips() {
+    round_trip(95, 14.0);
+}
+
+/// Silence before and after is the normal case — a receiver is not started at
+/// the instant the transmission does.
+#[test]
+fn survives_silence_around_the_transmission() {
+    let mode = mode_for_vis(44).expect("Martin M1");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let mut audio = vec![0.0f32; SAMPLE_RATE as usize * 2];
+    audio.extend(encode(mode, &frame, SAMPLE_RATE));
+    audio.extend(std::iter::repeat_n(0.0, SAMPLE_RATE as usize));
+
+    let (images, _) = decode(&audio);
+    assert_eq!(
+        images.len(),
+        1,
+        "expected one picture from a transmission in silence"
+    );
+    assert!(images[0].complete);
+}
+
+/// A transmission cut off part-way is what a fade or a shut-down transmitter
+/// produces. The lines that did arrive are worth keeping.
+#[test]
+fn a_truncated_transmission_still_yields_its_lines() {
+    let mode = mode_for_vis(44).expect("Martin M1");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let full = encode(mode, &frame, SAMPLE_RATE);
+    // Two thirds of the picture, then silence for long enough that the decoder
+    // stops waiting for the rest.
+    let mut audio = full[..full.len() * 2 / 3].to_vec();
+    audio.extend(std::iter::repeat_n(0.0, SAMPLE_RATE as usize * 5));
+
+    let (images, _) = decode(&audio);
+    assert_eq!(
+        images.len(),
+        1,
+        "a cut-off transmission produced no picture"
+    );
+    let image = &images[0];
+    assert!(
+        !image.complete,
+        "a two-thirds transmission reported as complete"
+    );
+    assert!(
+        image.lines > mode.height / 2 && image.lines < mode.height,
+        "{} lines of {} arrived",
+        image.lines,
+        mode.height,
+    );
+    // What did arrive is the top of the picture, and it is right.
+    let rows = usize::from(image.lines).saturating_sub(4);
+    let error = mean_error(&sent[..width * rows * 3], &image.rgb[..width * rows * 3]);
+    assert!(
+        error < 12.0,
+        "the lines that arrived are wrong: mean error {error:.1}"
+    );
+}
+
+/// Two pictures back to back: the decoder has to finish the first and pick up
+/// the header of the second.
+#[test]
+fn decodes_a_second_transmission_after_the_first() {
+    let mode = mode_for_vis(40).expect("Martin M2");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let one = encode(mode, &frame, SAMPLE_RATE);
+
+    let mut audio = one.clone();
+    audio.extend(std::iter::repeat_n(0.0, SAMPLE_RATE as usize / 2));
+    audio.extend(one);
+
+    let (images, _) = decode(&audio);
+    assert_eq!(
+        images.len(),
+        2,
+        "expected two pictures, got {}",
+        images.len()
+    );
+    assert!(
+        images.iter().all(|image| image.complete),
+        "a picture did not finish"
+    );
+}
+
+/// Noise on the signal is the normal condition on HF. The picture should
+/// degrade, not fall apart.
+#[test]
+fn decodes_through_noise() {
+    let mode = mode_for_vis(44).expect("Martin M1");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let clean = encode(mode, &frame, SAMPLE_RATE);
+
+    // Deterministic pseudo-noise at about 20 dB below the signal.
+    let mut seed = 0x5eed_1234u32;
+    let noisy: Vec<f32> = clean
+        .iter()
+        .map(|sample| {
+            seed = seed.wrapping_mul(1_664_525).wrapping_add(1_013_904_223);
+            let noise = (seed >> 8) as f32 / f32::from(u16::MAX) / 256.0 - 0.5;
+            sample + noise * 0.2
+        })
+        .collect();
+
+    let (images, _) = decode(&noisy);
+    assert_eq!(images.len(), 1, "noise cost the whole picture");
+    let image = &images[0];
+    assert!(image.complete, "noise cost the bottom of the picture");
+    let error = interior_error(width, height, &sent, &image.rgb);
+    assert!(error < 20.0, "mean error through noise {error:.1} levels");
+}
+
+/// The sound card that plays the signal and the one that records it never
+/// agree exactly. A part-per-thousand error is far worse than reality and the
+/// picture should still stand up.
+#[test]
+fn tolerates_a_transmitter_clock_that_runs_fast() {
+    let mode = mode_for_vis(44).expect("Martin M1");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    // Encoding at a slightly different rate and decoding at 48 kHz is exactly
+    // a clock error: every duration is stretched by the same factor.
+    let audio = encode(mode, &frame, 48_048);
+
+    let (images, _) = decode(&audio);
+    assert_eq!(images.len(), 1, "a 0.1% clock error cost the picture");
+    let error = interior_error(width, height, &sent, &images[0].rgb);
+    assert!(
+        error < 12.0,
+        "mean error with a fast clock {error:.1} levels"
+    );
+}

src/trx-client/src/audio_client.rs

@@ -27,11 +27,11 @@ use trx_core::audio::{
     write_vchan_uuid_msg, AudioStreamInfo, AUDIO_MSG_AIS_DECODE, AUDIO_MSG_APRS_DECODE,
     AUDIO_MSG_CW_DECODE, AUDIO_MSG_FT2_DECODE, AUDIO_MSG_FT4_DECODE, AUDIO_MSG_FT8_DECODE,
     AUDIO_MSG_HF_APRS_DECODE, AUDIO_MSG_HISTORY_COMPRESSED, AUDIO_MSG_LRPT_IMAGE,
-    AUDIO_MSG_LRPT_PROGRESS, AUDIO_MSG_RX_FRAME, AUDIO_MSG_RX_FRAME_CH, AUDIO_MSG_STREAM_INFO,
-    AUDIO_MSG_TX_FRAME, AUDIO_MSG_VCHAN_ALLOCATED, AUDIO_MSG_VCHAN_BW, AUDIO_MSG_VCHAN_DESTROYED,
-    AUDIO_MSG_VCHAN_FREQ, AUDIO_MSG_VCHAN_MODE, AUDIO_MSG_VCHAN_REMOVE, AUDIO_MSG_VCHAN_SUB,
-    AUDIO_MSG_VCHAN_UNSUB, AUDIO_MSG_VDES_DECODE, AUDIO_MSG_WEFAX_DECODE, AUDIO_MSG_WEFAX_PROGRESS,
-    AUDIO_MSG_WSPR_DECODE,
+    AUDIO_MSG_LRPT_PROGRESS, AUDIO_MSG_RX_FRAME, AUDIO_MSG_RX_FRAME_CH, AUDIO_MSG_SSTV_DECODE,
+    AUDIO_MSG_SSTV_PROGRESS, AUDIO_MSG_STREAM_INFO, AUDIO_MSG_TX_FRAME, AUDIO_MSG_VCHAN_ALLOCATED,
+    AUDIO_MSG_VCHAN_BW, AUDIO_MSG_VCHAN_DESTROYED, AUDIO_MSG_VCHAN_FREQ, AUDIO_MSG_VCHAN_MODE,
+    AUDIO_MSG_VCHAN_REMOVE, AUDIO_MSG_VCHAN_SUB, AUDIO_MSG_VCHAN_UNSUB, AUDIO_MSG_VDES_DECODE,
+    AUDIO_MSG_WEFAX_DECODE, AUDIO_MSG_WEFAX_PROGRESS, AUDIO_MSG_WSPR_DECODE,
 };
 use trx_core::decode::DecodedMessage;
 use trx_frontend::VChanAudioCmd;
@@ -533,7 +533,9 @@ async fn handle_single_rig_connection(
                     | AUDIO_MSG_LRPT_IMAGE
                     | AUDIO_MSG_LRPT_PROGRESS
                     | AUDIO_MSG_WEFAX_DECODE
-                    | AUDIO_MSG_WEFAX_PROGRESS,
+                    | AUDIO_MSG_WEFAX_PROGRESS
+                    | AUDIO_MSG_SSTV_DECODE
+                    | AUDIO_MSG_SSTV_PROGRESS,
                     payload,
                 )) => {
                     if let Ok(mut msg) = serde_json::from_slice::<DecodedMessage>(&payload) {

src/trx-client/src/main.rs

@@ -527,6 +527,9 @@ async fn async_init() -> DynResult<AppState> {
                 DecodedMessage::LrptProgress(_) => {}
                 DecodedMessage::Wefax(_) => {}
                 DecodedMessage::WefaxProgress(_) => {}
+                // Pictures replay from their own history, not this one.
+                DecodedMessage::Sstv(_) => {}
+                DecodedMessage::SstvProgress(_) => {}
             }
         });
 

src/trx-client/trx-frontend/src/lib.rs

@@ -17,8 +17,8 @@ use uuid::Uuid;
 
 use trx_core::audio::AudioStreamInfo;
 use trx_core::decode::{
-    AisMessage, AprsPacket, CwEvent, DecodedMessage, Ft8Message, VdesMessage, WefaxMessage,
-    WsprMessage,
+    AisMessage, AprsPacket, CwEvent, DecodedMessage, Ft8Message, SstvMessage, VdesMessage,
+    WefaxMessage, WsprMessage,
 };
 use trx_core::rig::state::{RigSnapshot, SpectrumData};
 use trx_core::{DynResult, RigRequest, RigState};
@@ -233,6 +233,7 @@ pub struct DecodeHistoryContext {
     pub ft2: DecodeHistory<Ft8Message>,
     pub wspr: DecodeHistory<WsprMessage>,
     pub wefax: DecodeHistory<WefaxMessage>,
+    pub sstv: DecodeHistory<SstvMessage>,
 }
 
 impl Default for DecodeHistoryContext {
@@ -248,6 +249,7 @@ impl Default for DecodeHistoryContext {
             ft2: Arc::new(Mutex::new(VecDeque::new())),
             wspr: Arc::new(Mutex::new(VecDeque::new())),
             wefax: Arc::new(Mutex::new(VecDeque::new())),
+            sstv: Arc::new(Mutex::new(VecDeque::new())),
         }
     }
 }

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js

@@ -885,7 +885,7 @@ function elementById(id) {
       if (restoreFocus) more.focus();
     };
     api.closeMobileOverlays = closeMore;
-    ["statistics", "recorder", "settings", "about"].forEach((tabName) => {
+    ["satellites", "statistics", "recorder", "settings", "about"].forEach((tabName) => {
       const source = nav.querySelector(`[data-tab="${tabName}"]`);
       if (!source) return;
       const item = document.createElement("button");
@@ -932,7 +932,7 @@ function elementById(id) {
       ["Overview", ["overview"]],
       ["Marine & packet", ["ais", "vdes", "aprs", "hf-aprs"]],
       ["Weak signal", ["cw", "ft8", "ft4", "ft2", "wspr"]],
-      ["Broadcast & images", ["rds", "sat", "wefax"]]
+      ["Broadcast & images", ["rds", "sat", "wefax", "sstv"]]
     ];
     groups.forEach(([label, ids]) => {
       const group = document.createElement("optgroup");
@@ -1529,6 +1529,7 @@ var TAB_ORDER = [
   "bookmarks",
   "digital-modes",
   "map",
+  "satellites",
   "statistics",
   "recorder",
   "settings",
@@ -1539,6 +1540,7 @@ var TAB_PATHS = {
   bookmarks: "/bookmarks",
   "digital-modes": "/digital-modes",
   map: "/map",
+  satellites: "/satellites",
   statistics: "/statistics",
   recorder: "/recorder",
   settings: "/settings",
@@ -1748,6 +1750,7 @@ var pluginGroups = {
     "/background-decode.js",
     "/sat.js",
     "/wefax.js",
+    "/sstv.js",
     "/ais.js",
     "/vdes.js",
     "/aprs.js",
@@ -1755,6 +1758,7 @@ var pluginGroups = {
   ],
   "map-data": ["/map-core.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js"],
   map: ["/map-core.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js", "/sat.js", "/sat-scheduler.js"],
+  satellites: ["/satellite-predictions.js"],
   statistics: ["/map-core.js"],
   bookmarks: ["/bookmarks.js"],
   recorder: [],
@@ -2240,7 +2244,7 @@ function currentDecodeHistoryRetentionMs() {
 }
 window.getDecodeHistoryRetentionMs = currentDecodeHistoryRetentionMs;
 window.applyDecodeHistoryRetention = function() {
-  for (const decoder of ["aprs", "hf_aprs", "ais", "vdes", "ft8", "ft4", "ft2", "wspr", "wefax"]) {
+  for (const decoder of ["aprs", "hf_aprs", "ais", "vdes", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"]) {
     window.trxPluginRuntime.prune(decoder);
   }
 };
@@ -4820,6 +4824,9 @@ function render(update) {
   for (const [key, entry] of Object.entries(_decoderToggles)) {
     syncDecoderToggle(entry, !!update[key], entry.label);
   }
+  if (typeof update.sstv_decode_enabled === "boolean" && window.syncSstvToggle) {
+    window.syncSstvToggle(update.sstv_decode_enabled);
+  }
   if (typeof update.wefax_decode_enabled === "boolean" && window.syncWefaxToggle) {
     window.syncWefaxToggle(update.wefax_decode_enabled);
   }
@@ -5840,6 +5847,7 @@ function _initMapWhenReady() {
 }
 function navigateToTab(name, options = {}) {
   window.trxUi?.closeMobileOverlays?.();
+  const leavingSatellites = _activeTab === "satellites" && name !== "satellites";
   const { updateHistory = true, replaceHistory = false } = options;
   if (authEnabled && !authRole && name !== "main") {
     showAuthGate(false);
@@ -5869,7 +5877,10 @@ function navigateToTab(name, options = {}) {
     updateTabHistory(name, replaceHistory);
   }
   scheduleSpectrumLayout();
-  void loadPluginsForTab(name).catch((error) => {
+  if (leavingSatellites) window.clearSatPredictionDom?.();
+  void loadPluginsForTab(name).then(() => {
+    if (name === "satellites") window.refreshSatPredictions?.();
+  }).catch((error) => {
     console.error(error);
   });
   if (name === "map") {
@@ -6316,9 +6327,6 @@ function _wireSubTabBar(bar) {
         if (window.refreshCwTonePicker) window.refreshCwTonePicker();
       });
     }
-    if (btn.dataset.subtab !== "sat" && typeof window.clearSatPredictionDom === "function") {
-      window.clearSatPredictionDom();
-    }
   });
 }
 document.querySelectorAll(".sub-tab-bar").forEach(_wireSubTabBar);
@@ -7594,9 +7602,17 @@ function updateDecodeStatus(text) {
     if (el && el.textContent !== "Receiving") el.textContent = text;
   }
 }
+var IMAGE_DECODE_KINDS = /* @__PURE__ */ new Set([
+  "lrpt_image",
+  "lrpt_progress",
+  "wefax",
+  "wefax_progress",
+  "sstv",
+  "sstv_progress"
+]);
 function dispatchDecodeMessage(msg, skipStats = false) {
   if (msg.type) window.trxPluginRuntime.dispatch(msg.type, msg);
-  if (!skipStats && msg.type && msg.type !== "lrpt_image" && msg.type !== "lrpt_progress" && msg.type !== "wefax" && msg.type !== "wefax_progress") {
+  if (!skipStats && msg.type && !IMAGE_DECODE_KINDS.has(msg.type)) {
     window.trx.modules.map?.statsRecordDecode(msg.type, msg.rig_id || msg.remote || null);
     window.trx.modules.map?.scheduleStatsRender();
   }
@@ -7642,7 +7658,7 @@ function loadDecodeHistoryOnMainThread(onReady, onError) {
 }
 function restoreDecodeHistoryGroup(kind, messages) {
   if (!Array.isArray(messages) || messages.length === 0) return;
-  if (kind !== "lrpt_image" && kind !== "lrpt_progress" && kind !== "wefax" && kind !== "wefax_progress") {
+  if (!IMAGE_DECODE_KINDS.has(kind)) {
     for (const msg of messages) {
       window.trx.modules.map?.statsRecordDecode(kind, msg.rig_id || msg.remote || null, msg.ts_ms || void 0);
     }

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/decode-history-worker.js

@@ -2,7 +2,7 @@
 (() => {
   // src/decode-history-worker.ts
   var textDecoder = typeof TextDecoder === "function" ? new TextDecoder() : null;
-  var HISTORY_GROUP_KEYS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax"];
+  var HISTORY_GROUP_KEYS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"];
   var workerScope = self;
   function decodeCborUint(view, bytes, state, additional) {
     const offset = state.offset;

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/sat.js

@@ -8,7 +8,6 @@ var satDom = {
   status: document.getElementById("sat-status"),
   liveView: document.getElementById("sat-live-view"),
   historyView: document.getElementById("sat-history-view"),
-  predictionsView: document.getElementById("sat-predictions-view"),
   liveLatest: document.getElementById("sat-live-latest"),
   historyList: document.getElementById("sat-history-list"),
   historyCount: document.getElementById("sat-history-count"),
@@ -17,29 +16,12 @@ var satDom = {
   typeFilter: document.getElementById("sat-type-filter"),
   lrptState: document.getElementById("sat-lrpt-state"),
   viewLiveBtn: document.getElementById("sat-view-live"),
-  viewHistoryBtn: document.getElementById("sat-view-history"),
-  viewPredBtn: document.getElementById("sat-view-predictions"),
-  predFilter: document.getElementById("sat-pred-filter"),
-  predMinEl: document.getElementById("sat-pred-min-el"),
-  predCategory: document.getElementById("sat-pred-category"),
-  predCurrentList: document.getElementById("sat-pred-current-list"),
-  predUpcomingList: document.getElementById("sat-pred-list"),
-  predCurrentSec: document.getElementById("sat-pred-current-section"),
-  predUpcomingSec: document.getElementById("sat-pred-upcoming-section"),
-  predStatus: document.getElementById("sat-pred-status")
+  viewHistoryBtn: document.getElementById("sat-view-history")
 };
 var satImageHistory = [];
 var SAT_MAX_IMAGES = 100;
-var SAT_PRED_PAGE_SIZE = 50;
-var satPredShowAll = false;
 var satFilterText = "";
 var satActiveView = "live";
-var satPredData = [];
-var satPredFilterText = "";
-var satPredMinEl = 0;
-var satPredCategory = "all";
-var satPredSatCount = 0;
-var satPredCountdownTimer = null;
 function scheduleSatUi(key, job) {
   if (typeof satWindow.trxScheduleUiFrameJob === "function") {
     satWindow.trxScheduleUiFrameJob(key, job);
@@ -48,37 +30,19 @@ function scheduleSatUi(key, job) {
   job();
 }
 function switchSatView(view) {
-  const leavingPredictions = satActiveView === "predictions" && view !== "predictions";
   satActiveView = view;
   if (satDom.liveView) satDom.liveView.style.display = view === "live" ? "" : "none";
   if (satDom.historyView) satDom.historyView.style.display = view === "history" ? "" : "none";
-  if (satDom.predictionsView) satDom.predictionsView.style.display = view === "predictions" ? "" : "none";
   if (satDom.viewLiveBtn) satDom.viewLiveBtn.classList.toggle("sat-view-active", view === "live");
   if (satDom.viewHistoryBtn) satDom.viewHistoryBtn.classList.toggle("sat-view-active", view === "history");
-  if (satDom.viewPredBtn) satDom.viewPredBtn.classList.toggle("sat-view-active", view === "predictions");
-  if (leavingPredictions) clearPredictionDom();
-  if (view === "history") {
-    renderSatHistoryTable();
-  } else if (view === "predictions") {
-    satPredShowAll = false;
-    void loadSatPredictions();
-  }
+  if (view === "history") renderSatHistoryTable();
 }
-function clearPredictionDom() {
-  stopCountdownTimer();
-  if (satDom.predCurrentList) satDom.predCurrentList.innerHTML = "";
-  if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-}
-satWindow.clearSatPredictionDom = clearPredictionDom;
 satDom.viewLiveBtn?.addEventListener("click", () => {
   switchSatView("live");
 });
 satDom.viewHistoryBtn?.addEventListener("click", () => {
   switchSatView("history");
 });
-satDom.viewPredBtn?.addEventListener("click", () => {
-  switchSatView("predictions");
-});
 var lastSatLrptOn = null;
 satWindow.updateSatLiveState = function(update) {
   if (!satDom.lrptState) return;
@@ -275,200 +239,6 @@ document.getElementById("settings-clear-sat-history")?.addEventListener("click",
     }
   })();
 });
-function azToCardinal(deg) {
-  const dirs = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
-  return dirs[Math.round(deg / 45) % 8] ?? "N";
-}
-function formatPredTime(ms) {
-  const d = new Date(ms);
-  const now = /* @__PURE__ */ new Date();
-  const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
-  const day = d.getUTCDay() !== now.getUTCDay() ? `${dayNames[d.getUTCDay()] ?? ""} ` : "";
-  const hh = String(d.getUTCHours()).padStart(2, "0");
-  const mm = String(d.getUTCMinutes()).padStart(2, "0");
-  return `${day}${hh}:${mm}`;
-}
-function formatPredDuration(s) {
-  if (s >= 60) return `${Math.round(s / 60)} min`;
-  return `${s}s`;
-}
-function formatCountdown(ms) {
-  const totalSec = Math.max(0, Math.floor(ms / 1e3));
-  const m = Math.floor(totalSec / 60);
-  const s = totalSec % 60;
-  return `${m}:${String(s).padStart(2, "0")}`;
-}
-function elevationClass(deg) {
-  if (deg >= 45) return "sat-pred-el-high";
-  if (deg >= 10) return "sat-pred-el-mid";
-  return "sat-pred-el-low";
-}
-function stopCountdownTimer() {
-  if (satPredCountdownTimer) {
-    clearInterval(satPredCountdownTimer);
-    satPredCountdownTimer = null;
-  }
-}
-function startCountdownTimer(container) {
-  const countdownEls = container?.querySelectorAll(".sat-pred-col-countdown") ?? [];
-  if (countdownEls.length === 0) return;
-  satPredCountdownTimer = setInterval(() => {
-    if (satActiveView !== "predictions") {
-      stopCountdownTimer();
-      return;
-    }
-    const n = Date.now();
-    let anyActive = false;
-    for (const el of countdownEls) {
-      const los = Number.parseInt(el.dataset.los ?? "0", 10);
-      const rem = los - n;
-      if (rem > 0) {
-        el.textContent = formatCountdown(rem);
-        anyActive = true;
-      } else {
-        el.textContent = "0:00";
-      }
-    }
-    if (!anyActive) {
-      stopCountdownTimer();
-      renderSatPredictions(getFilteredPredictions());
-    }
-  }, 1e3);
-}
-function buildCurrentPassRow(pass, now) {
-  const row = document.createElement("div");
-  row.className = "sat-pred-row-current";
-  const dir = `${azToCardinal(pass.azimuth_aos_deg)} → ${azToCardinal(pass.azimuth_los_deg)}`;
-  const remaining = Math.max(0, pass.los_ms - now);
-  row.innerHTML = [
-    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
-    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}°</span>`,
-    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
-    `<span class="sat-pred-col-time">${formatPredTime(pass.los_ms)}</span>`,
-    `<span class="sat-pred-col-countdown" data-los="${pass.los_ms}">${formatCountdown(remaining)}</span>`,
-    `<span class="sat-pred-col-dir">${dir}</span>`
-  ].join("");
-  return row;
-}
-function buildUpcomingPassRow(pass) {
-  const row = document.createElement("div");
-  row.className = "sat-pred-row";
-  const dir = `${azToCardinal(pass.azimuth_aos_deg)} → ${azToCardinal(pass.azimuth_los_deg)}`;
-  row.innerHTML = [
-    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
-    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
-    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}°</span>`,
-    `<span class="sat-pred-col-dur">${formatPredDuration(pass.duration_s)}</span>`,
-    `<span class="sat-pred-col-dir">${dir}</span>`
-  ].join("");
-  return row;
-}
-function getFilteredPredictions() {
-  let items = satPredData;
-  if (satPredCategory !== "all") items = items.filter((p) => p.category === satPredCategory);
-  if (satPredMinEl > 0) items = items.filter((p) => p.max_elevation_deg >= satPredMinEl);
-  if (satPredFilterText) items = items.filter((p) => p.satellite.toUpperCase().includes(satPredFilterText));
-  return items;
-}
-function applyPredFilters() {
-  renderSatPredictions(getFilteredPredictions());
-}
-var satPredictionFilter = satDom.predFilter;
-satPredictionFilter?.addEventListener("input", () => {
-  satPredFilterText = satPredictionFilter.value.trim().toUpperCase();
-  applyPredFilters();
-});
-var satPredictionMinElevation = satDom.predMinEl;
-satPredictionMinElevation?.addEventListener("change", () => {
-  satPredMinEl = Number.parseInt(satPredictionMinElevation.value, 10) || 0;
-  applyPredFilters();
-});
-var satPredictionCategory = satDom.predCategory;
-satPredictionCategory?.addEventListener("change", () => {
-  satPredCategory = satPredictionCategory.value;
-  applyPredFilters();
-});
-function renderSatPredictions(passes, error) {
-  stopCountdownTimer();
-  if (error) {
-    if (satDom.predCurrentList) satDom.predCurrentList.innerHTML = "";
-    if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-    if (satDom.predCurrentSec) satDom.predCurrentSec.style.display = "none";
-    if (satDom.predUpcomingSec) satDom.predUpcomingSec.style.display = "none";
-    if (satDom.predStatus) satDom.predStatus.textContent = error;
-    return;
-  }
-  if (!Array.isArray(passes) || passes.length === 0) {
-    if (satDom.predCurrentList) satDom.predCurrentList.innerHTML = "";
-    if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-    if (satDom.predCurrentSec) satDom.predCurrentSec.style.display = "none";
-    if (satDom.predUpcomingSec) satDom.predUpcomingSec.style.display = "none";
-    if (satDom.predStatus) satDom.predStatus.textContent = "No passes found in the next 24 hours.";
-    return;
-  }
-  const now = Date.now();
-  const current = passes.filter((p) => p.aos_ms <= now && p.los_ms > now);
-  const upcoming = passes.filter((p) => p.aos_ms > now);
-  if (satDom.predCurrentSec) satDom.predCurrentSec.style.display = current.length > 0 ? "" : "none";
-  if (satDom.predCurrentList) {
-    if (current.length === 0) {
-      satDom.predCurrentList.innerHTML = "";
-    } else {
-      const frag = document.createDocumentFragment();
-      for (const pass of current) frag.appendChild(buildCurrentPassRow(pass, now));
-      satDom.predCurrentList.replaceChildren(frag);
-    }
-  }
-  const upcomingLimit = satPredShowAll ? upcoming.length : SAT_PRED_PAGE_SIZE;
-  const visibleUpcoming = upcoming.slice(0, upcomingLimit);
-  const hiddenCount = upcoming.length - visibleUpcoming.length;
-  if (satDom.predUpcomingSec) satDom.predUpcomingSec.style.display = upcoming.length > 0 ? "" : "none";
-  if (satDom.predUpcomingList) {
-    const frag = document.createDocumentFragment();
-    for (const pass of visibleUpcoming) frag.appendChild(buildUpcomingPassRow(pass));
-    if (hiddenCount > 0) {
-      const moreRow = document.createElement("div");
-      moreRow.className = "sat-pred-row";
-      moreRow.style.cursor = "pointer";
-      moreRow.style.textAlign = "center";
-      moreRow.innerHTML = `<span style="grid-column:1/-1;color:var(--accent);font-size:0.82rem;">Show ${hiddenCount} more passes…</span>`;
-      moreRow.addEventListener("click", () => {
-        satPredShowAll = true;
-        renderSatPredictions(getFilteredPredictions());
-      });
-      frag.appendChild(moreRow);
-    }
-    satDom.predUpcomingList.replaceChildren(frag);
-  }
-  if (satDom.predStatus) {
-    let text = `${current.length} active · ${upcoming.length} upcoming · times in UTC`;
-    if (satPredSatCount > 0) text += ` · ${satPredSatCount} satellites tracked`;
-    satDom.predStatus.textContent = text;
-  }
-  if (current.length > 0 && satActiveView === "predictions") {
-    startCountdownTimer(satDom.predCurrentList);
-  }
-}
-async function loadSatPredictions() {
-  if (satDom.predStatus) satDom.predStatus.textContent = "Loading predictions…";
-  if (satDom.predCurrentList) satDom.predCurrentList.innerHTML = "";
-  if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-  try {
-    const resp = await fetch("/sat_passes");
-    if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
-    const data = await resp.json();
-    satPredSatCount = data.satellite_count || 0;
-    if (data.error) {
-      satPredData = [];
-      renderSatPredictions([], data.error);
-    } else {
-      satPredData = data.passes || [];
-      renderSatPredictions(getFilteredPredictions());
-    }
-  } catch (error) {
-    renderSatPredictions([], `Failed to load predictions: ${error instanceof Error ? error.message : String(error)}`);
-  }
-}
 satWindow.satShowOnMap = function(south, west, north, east) {
   if (typeof satWindow.enableMapSourceFilter === "function") {
     satWindow.enableMapSourceFilter("sat");

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/satellite-predictions.js

@@ -0,0 +1,228 @@
+// src/plugins/satellite-predictions.ts
+var predWindow = window;
+var dom = {
+  page: document.getElementById("tab-satellites"),
+  filter: document.getElementById("sat-pred-filter"),
+  minElevation: document.getElementById("sat-pred-min-el"),
+  category: document.getElementById("sat-pred-category"),
+  currentList: document.getElementById("sat-pred-current-list"),
+  upcomingList: document.getElementById("sat-pred-list"),
+  currentSection: document.getElementById("sat-pred-current-section"),
+  upcomingSection: document.getElementById("sat-pred-upcoming-section"),
+  status: document.getElementById("sat-pred-status")
+};
+var PAGE_SIZE = 50;
+var predShowAll = false;
+var predData = [];
+var predFilterText = "";
+var predMinEl = 0;
+var predCategory = "all";
+var predSatCount = 0;
+var predCountdownTimer = null;
+function isPageVisible() {
+  return !!dom.page && dom.page.style.display !== "none";
+}
+function azToCardinal(deg) {
+  const dirs = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
+  return dirs[Math.round(deg / 45) % 8] ?? "N";
+}
+function formatPredTime(ms) {
+  const d = new Date(ms);
+  const now = /* @__PURE__ */ new Date();
+  const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
+  const day = d.getUTCDay() !== now.getUTCDay() ? `${dayNames[d.getUTCDay()] ?? ""} ` : "";
+  const hh = String(d.getUTCHours()).padStart(2, "0");
+  const mm = String(d.getUTCMinutes()).padStart(2, "0");
+  return `${day}${hh}:${mm}`;
+}
+function formatPredDuration(s) {
+  if (s >= 60) return `${Math.round(s / 60)} min`;
+  return `${s}s`;
+}
+function formatCountdown(ms) {
+  const totalSec = Math.max(0, Math.floor(ms / 1e3));
+  const m = Math.floor(totalSec / 60);
+  const s = totalSec % 60;
+  return `${m}:${String(s).padStart(2, "0")}`;
+}
+function elevationClass(deg) {
+  if (deg >= 45) return "sat-pred-el-high";
+  if (deg >= 10) return "sat-pred-el-mid";
+  return "sat-pred-el-low";
+}
+function stopCountdownTimer() {
+  if (predCountdownTimer) {
+    clearInterval(predCountdownTimer);
+    predCountdownTimer = null;
+  }
+}
+function startCountdownTimer(container) {
+  const countdownEls = container?.querySelectorAll(".sat-pred-col-countdown") ?? [];
+  if (countdownEls.length === 0) return;
+  predCountdownTimer = setInterval(() => {
+    if (!isPageVisible()) {
+      stopCountdownTimer();
+      return;
+    }
+    const n = Date.now();
+    let anyActive = false;
+    for (const el of countdownEls) {
+      const los = Number.parseInt(el.dataset.los ?? "0", 10);
+      const rem = los - n;
+      if (rem > 0) {
+        el.textContent = formatCountdown(rem);
+        anyActive = true;
+      } else {
+        el.textContent = "0:00";
+      }
+    }
+    if (!anyActive) {
+      stopCountdownTimer();
+      render(filtered());
+    }
+  }, 1e3);
+}
+function buildCurrentPassRow(pass, now) {
+  const row = document.createElement("div");
+  row.className = "sat-pred-row-current";
+  const dir = `${azToCardinal(pass.azimuth_aos_deg)} → ${azToCardinal(pass.azimuth_los_deg)}`;
+  const remaining = Math.max(0, pass.los_ms - now);
+  row.innerHTML = [
+    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
+    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}°</span>`,
+    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
+    `<span class="sat-pred-col-time">${formatPredTime(pass.los_ms)}</span>`,
+    `<span class="sat-pred-col-countdown" data-los="${pass.los_ms}">${formatCountdown(remaining)}</span>`,
+    `<span class="sat-pred-col-dir">${dir}</span>`
+  ].join("");
+  return row;
+}
+function buildUpcomingPassRow(pass) {
+  const row = document.createElement("div");
+  row.className = "sat-pred-row";
+  const dir = `${azToCardinal(pass.azimuth_aos_deg)} → ${azToCardinal(pass.azimuth_los_deg)}`;
+  row.innerHTML = [
+    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
+    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
+    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}°</span>`,
+    `<span class="sat-pred-col-dur">${formatPredDuration(pass.duration_s)}</span>`,
+    `<span class="sat-pred-col-dir">${dir}</span>`
+  ].join("");
+  return row;
+}
+function filtered() {
+  let items = predData;
+  if (predCategory !== "all") items = items.filter((p) => p.category === predCategory);
+  if (predMinEl > 0) items = items.filter((p) => p.max_elevation_deg >= predMinEl);
+  if (predFilterText) items = items.filter((p) => p.satellite.toUpperCase().includes(predFilterText));
+  return items;
+}
+function applyFilters() {
+  render(filtered());
+}
+var filterInput = dom.filter;
+filterInput?.addEventListener("input", () => {
+  predFilterText = filterInput.value.trim().toUpperCase();
+  applyFilters();
+});
+var minElevationSelect = dom.minElevation;
+minElevationSelect?.addEventListener("change", () => {
+  predMinEl = Number.parseInt(minElevationSelect.value, 10) || 0;
+  applyFilters();
+});
+var categorySelect = dom.category;
+categorySelect?.addEventListener("change", () => {
+  predCategory = categorySelect.value;
+  applyFilters();
+});
+function render(passes, error) {
+  stopCountdownTimer();
+  if (error) {
+    if (dom.currentList) dom.currentList.innerHTML = "";
+    if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+    if (dom.currentSection) dom.currentSection.style.display = "none";
+    if (dom.upcomingSection) dom.upcomingSection.style.display = "none";
+    if (dom.status) dom.status.textContent = error;
+    return;
+  }
+  if (!Array.isArray(passes) || passes.length === 0) {
+    if (dom.currentList) dom.currentList.innerHTML = "";
+    if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+    if (dom.currentSection) dom.currentSection.style.display = "none";
+    if (dom.upcomingSection) dom.upcomingSection.style.display = "none";
+    if (dom.status) dom.status.textContent = "No passes found in the next 24 hours.";
+    return;
+  }
+  const now = Date.now();
+  const current = passes.filter((p) => p.aos_ms <= now && p.los_ms > now);
+  const upcoming = passes.filter((p) => p.aos_ms > now);
+  if (dom.currentSection) dom.currentSection.style.display = current.length > 0 ? "" : "none";
+  if (dom.currentList) {
+    if (current.length === 0) {
+      dom.currentList.innerHTML = "";
+    } else {
+      const frag = document.createDocumentFragment();
+      for (const pass of current) frag.appendChild(buildCurrentPassRow(pass, now));
+      dom.currentList.replaceChildren(frag);
+    }
+  }
+  const upcomingLimit = predShowAll ? upcoming.length : PAGE_SIZE;
+  const visibleUpcoming = upcoming.slice(0, upcomingLimit);
+  const hiddenCount = upcoming.length - visibleUpcoming.length;
+  if (dom.upcomingSection) dom.upcomingSection.style.display = upcoming.length > 0 ? "" : "none";
+  if (dom.upcomingList) {
+    const frag = document.createDocumentFragment();
+    for (const pass of visibleUpcoming) frag.appendChild(buildUpcomingPassRow(pass));
+    if (hiddenCount > 0) {
+      const moreRow = document.createElement("div");
+      moreRow.className = "sat-pred-row";
+      moreRow.style.cursor = "pointer";
+      moreRow.style.textAlign = "center";
+      moreRow.innerHTML = `<span style="grid-column:1/-1;color:var(--accent);font-size:0.82rem;">Show ${hiddenCount} more passes…</span>`;
+      moreRow.addEventListener("click", () => {
+        predShowAll = true;
+        render(filtered());
+      });
+      frag.appendChild(moreRow);
+    }
+    dom.upcomingList.replaceChildren(frag);
+  }
+  if (dom.status) {
+    let text = `${current.length} active · ${upcoming.length} upcoming · times in UTC`;
+    if (predSatCount > 0) text += ` · ${predSatCount} satellites tracked`;
+    dom.status.textContent = text;
+  }
+  if (current.length > 0 && isPageVisible()) {
+    startCountdownTimer(dom.currentList);
+  }
+}
+async function load() {
+  if (dom.status) dom.status.textContent = "Loading predictions…";
+  if (dom.currentList) dom.currentList.innerHTML = "";
+  if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+  try {
+    const resp = await fetch("/sat_passes");
+    if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
+    const data = await resp.json();
+    predSatCount = data.satellite_count || 0;
+    if (data.error) {
+      predData = [];
+      render([], data.error);
+    } else {
+      predData = data.passes || [];
+      render(filtered());
+    }
+  } catch (error) {
+    render([], `Failed to load predictions: ${error instanceof Error ? error.message : String(error)}`);
+  }
+}
+function clearPredictionDom() {
+  stopCountdownTimer();
+  if (dom.currentList) dom.currentList.innerHTML = "";
+  if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+}
+predWindow.clearSatPredictionDom = clearPredictionDom;
+predWindow.refreshSatPredictions = function() {
+  predShowAll = false;
+  void load();
+};

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/sstv.js

@@ -0,0 +1,249 @@
+import {
+  hostCore
+} from "./chunk-KL66PICH.js";
+
+// src/plugins/sstv.ts
+var sstvWindow = window;
+var sstvDom = {
+  status: document.getElementById("sstv-status"),
+  liveView: document.getElementById("sstv-live-view"),
+  historyView: document.getElementById("sstv-history-view"),
+  liveContainer: document.getElementById("sstv-live-container"),
+  liveInfo: document.getElementById("sstv-live-info"),
+  liveCanvas: document.getElementById("sstv-live-canvas"),
+  liveLatest: document.getElementById("sstv-live-latest"),
+  historyList: document.getElementById("sstv-history-list"),
+  historyCount: document.getElementById("sstv-history-count"),
+  filterInput: document.getElementById("sstv-filter"),
+  sortSelect: document.getElementById("sstv-sort"),
+  toggleBtn: document.getElementById("sstv-decode-toggle-btn"),
+  clearBtn: document.getElementById("sstv-clear-btn"),
+  viewLiveBtn: document.getElementById("sstv-view-live"),
+  viewHistoryBtn: document.getElementById("sstv-view-history")
+};
+var SSTV_MAX_IMAGES = 100;
+var sstvHistory = [];
+var liveCtx = null;
+var liveMode = "";
+var liveHeight = 0;
+var liveRows = 0;
+var activeView = "live";
+var filterText = "";
+function retentionMs() {
+  return sstvWindow.getDecodeHistoryRetentionMs?.() ?? 24 * 60 * 60 * 1e3;
+}
+function pruneHistory() {
+  const cutoff = Date.now() - retentionMs();
+  sstvHistory = sstvHistory.filter((image) => (image._tsMs || 0) > cutoff);
+}
+function escapeHtml(value) {
+  return String(value).replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/"/g, "&quot;");
+}
+function scheduleUi(key, job) {
+  if (typeof sstvWindow.trxScheduleUiFrameJob === "function") {
+    sstvWindow.trxScheduleUiFrameJob(key, job);
+    return;
+  }
+  job();
+}
+function imageUrl(image) {
+  if (!image.path) return null;
+  const filename = image.path.split(/[\\/]/).pop();
+  return filename ? `/sstv-images/${encodeURIComponent(filename)}` : null;
+}
+function decodeBase64(data) {
+  const binary = atob(data);
+  const bytes = new Uint8Array(binary.length);
+  for (let i = 0; i < binary.length; i += 1) bytes[i] = binary.charCodeAt(i);
+  return bytes;
+}
+function switchView(view) {
+  activeView = view;
+  if (sstvDom.liveView) sstvDom.liveView.style.display = view === "live" ? "" : "none";
+  if (sstvDom.historyView) sstvDom.historyView.style.display = view === "history" ? "" : "none";
+  for (const button of [sstvDom.viewLiveBtn, sstvDom.viewHistoryBtn]) {
+    button?.classList.remove("sat-view-active");
+  }
+  if (view === "live") sstvDom.viewLiveBtn?.classList.add("sat-view-active");
+  else sstvDom.viewHistoryBtn?.classList.add("sat-view-active");
+  if (view === "history") renderHistoryTable();
+}
+sstvDom.viewLiveBtn?.addEventListener("click", () => {
+  switchView("live");
+});
+sstvDom.viewHistoryBtn?.addEventListener("click", () => {
+  switchView("history");
+});
+function beginPicture(mode, width, height) {
+  const canvas = sstvDom.liveCanvas;
+  if (!canvas || width <= 0 || height <= 0) return;
+  liveMode = mode;
+  liveHeight = height;
+  liveRows = 0;
+  canvas.width = width;
+  canvas.height = height;
+  liveCtx = canvas.getContext("2d");
+  if (!liveCtx) return;
+  liveCtx.fillStyle = "#606060";
+  liveCtx.fillRect(0, 0, width, height);
+  if (sstvDom.liveContainer) sstvDom.liveContainer.style.display = "";
+  updateLiveInfo();
+}
+function updateLiveInfo() {
+  if (!sstvDom.liveInfo) return;
+  const canvas = sstvDom.liveCanvas;
+  const size = canvas ? `${canvas.width}×${canvas.height}` : "";
+  sstvDom.liveInfo.textContent = liveMode ? `${liveMode} · ${size} · line ${liveRows}${liveHeight ? ` of ${liveHeight}` : ""}` : "";
+}
+function paintRow(line, rgb) {
+  const canvas = sstvDom.liveCanvas;
+  if (!liveCtx || !canvas) return;
+  const width = canvas.width;
+  if (line < 0 || line >= canvas.height || rgb.length < width * 3) return;
+  const row = liveCtx.createImageData(width, 1);
+  for (let x = 0; x < width; x += 1) {
+    row.data[x * 4] = rgb[x * 3] ?? 0;
+    row.data[x * 4 + 1] = rgb[x * 3 + 1] ?? 0;
+    row.data[x * 4 + 2] = rgb[x * 3 + 2] ?? 0;
+    row.data[x * 4 + 3] = 255;
+  }
+  liveCtx.putImageData(row, 0, line);
+  liveRows = Math.max(liveRows, line + 1);
+}
+function onProgress(msg) {
+  if (msg.state) {
+    if (sstvDom.status) sstvDom.status.textContent = msg.state;
+    beginPicture(msg.mode || "", msg.width || 0, msg.height || 0);
+    return;
+  }
+  if (typeof msg.line !== "number" || !msg.line_data) return;
+  const line = msg.line;
+  const rgb = decodeBase64(msg.line_data);
+  scheduleUi(`sstv-row-${line}`, () => {
+    paintRow(line, rgb);
+    updateLiveInfo();
+  });
+}
+function onImage(msg) {
+  const image = { ...msg };
+  image._tsMs = typeof msg.ts_ms === "number" ? msg.ts_ms : Date.now();
+  image._ts = new Date(image._tsMs).toLocaleTimeString();
+  sstvHistory.push(image);
+  if (sstvHistory.length > SSTV_MAX_IMAGES) sstvHistory.shift();
+  pruneHistory();
+  if (sstvDom.status) {
+    sstvDom.status.textContent = image.complete ? `Received ${image.mode ?? "picture"}` : `Partial ${image.mode ?? "picture"} — ${image.lines ?? 0} lines`;
+  }
+  scheduleUi("sstv-latest", renderLatestCard);
+  if (activeView === "history") scheduleUi("sstv-history", renderHistoryTable);
+}
+function renderLatestCard() {
+  if (!sstvDom.liveLatest) return;
+  const latest = sstvHistory[sstvHistory.length - 1];
+  if (!latest) {
+    sstvDom.liveLatest.innerHTML = "";
+    return;
+  }
+  const url = imageUrl(latest);
+  const lines = `${latest.lines ?? 0}${latest.height ? ` of ${latest.height}` : ""} lines`;
+  const state = latest.complete ? "complete" : "partial";
+  sstvDom.liveLatest.innerHTML = `
+    <div class="sat-latest-card">
+      <div style="display:flex; align-items:baseline; gap:0.5rem; flex-wrap:wrap;">
+        <strong>${escapeHtml(latest.mode ?? "SSTV")}</strong>
+        <small style="color:var(--text-muted);">${escapeHtml(latest._ts ?? "")} · ${lines} · ${state}</small>
+      </div>
+      ${url ? `<a href="${escapeHtml(url)}" target="_blank" rel="noopener">
+             <img src="${escapeHtml(url)}" alt="Received ${escapeHtml(latest.mode ?? "SSTV")} picture"
+                  style="margin-top:0.4rem; width:100%; max-width:640px; image-rendering:pixelated;" />
+           </a>` : ""}
+    </div>`;
+}
+function filteredHistory() {
+  const text = filterText.trim().toLowerCase();
+  const matching = text ? sstvHistory.filter((image) => (image.mode ?? "").toLowerCase().includes(text)) : sstvHistory.slice();
+  const newestFirst = (sstvDom.sortSelect?.value ?? "newest") === "newest";
+  matching.sort((a, b) => (newestFirst ? 1 : -1) * ((b._tsMs ?? 0) - (a._tsMs ?? 0)));
+  return matching;
+}
+function renderHistoryTable() {
+  if (!sstvDom.historyList) return;
+  pruneHistory();
+  const rows = filteredHistory();
+  sstvDom.historyList.innerHTML = rows.map((image) => {
+    const url = imageUrl(image);
+    const size = image.width && image.height ? `${image.width}×${image.height}` : "--";
+    const lines = image.complete ? String(image.lines ?? 0) : `${image.lines ?? 0} (partial)`;
+    return `<div class="sat-history-row">
+        <span class="sat-col-time">${escapeHtml(image._ts ?? "")}</span>
+        <span class="sat-col-type">${escapeHtml(image.mode ?? "--")}</span>
+        <span class="sat-col-sat">${escapeHtml(size)}</span>
+        <span class="sat-col-lines">${escapeHtml(lines)}</span>
+        <span class="sat-col-link">${url ? `<a href="${escapeHtml(url)}" target="_blank" rel="noopener">View</a>` : "--"}</span>
+      </div>`;
+  }).join("");
+  if (sstvDom.historyCount) {
+    sstvDom.historyCount.textContent = rows.length ? `${rows.length} picture${rows.length === 1 ? "" : "s"}` : "No pictures yet";
+  }
+}
+sstvDom.filterInput?.addEventListener("input", () => {
+  filterText = sstvDom.filterInput?.value ?? "";
+  renderHistoryTable();
+});
+sstvDom.sortSelect?.addEventListener("change", () => {
+  renderHistoryTable();
+});
+function restoreHistory(entries) {
+  if (!Array.isArray(entries)) return;
+  for (const entry of entries) onImage(entry);
+}
+function resetHistoryView() {
+  sstvHistory = [];
+  liveRows = 0;
+  liveMode = "";
+  if (sstvDom.liveContainer) sstvDom.liveContainer.style.display = "none";
+  if (sstvDom.status) sstvDom.status.textContent = "Idle";
+  renderLatestCard();
+  renderHistoryTable();
+}
+sstvWindow.syncSstvToggle = function syncSstvToggle(enabled) {
+  const button = sstvDom.toggleBtn;
+  if (!button) return;
+  button.textContent = enabled ? "Disable SSTV" : "Enable SSTV";
+  button.setAttribute("aria-pressed", String(enabled));
+  button.classList.toggle("is-active", enabled);
+};
+sstvDom.toggleBtn?.addEventListener("click", () => {
+  void (async () => {
+    try {
+      if (sstvDom.toggleBtn) {
+        await sstvWindow.takeSchedulerControlForDecoderDisable?.(sstvDom.toggleBtn);
+      }
+      await hostCore.postPath("/toggle_sstv_decode");
+    } catch (e) {
+      console.error("SSTV toggle failed", e);
+    }
+  })();
+});
+sstvDom.clearBtn?.addEventListener("click", () => {
+  void (async () => {
+    try {
+      await hostCore.postPath("/clear_sstv_decode");
+      resetHistoryView();
+    } catch (e) {
+      console.error("SSTV clear failed", e);
+    }
+  })();
+});
+renderLatestCard();
+sstvWindow.trxPluginRuntime.registerDecoder({
+  id: "sstv",
+  onMessage: onImage,
+  restore: restoreHistory,
+  prune: renderHistoryTable,
+  reset: resetHistoryView
+});
+sstvWindow.trxPluginRuntime.registerDecoder({
+  id: "sstv_progress",
+  onMessage: onProgress
+});

src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html

@@ -24,6 +24,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
     <symbol id="icon-bookmark" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><path d="M4 2h8v12l-4-2.5L4 14V2z"/></symbol>
     <symbol id="icon-digital" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><path d="M1 11.5h2.6V4.5h3.2v7h3.2v-7h3.2v7H15"/></symbol>
     <symbol id="icon-map" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><path d="M8 2a4 4 0 0 1 4 4c0 3-4 8-4 8S4 9 4 6a4 4 0 0 1 4-4z"/><circle cx="8" cy="6" r="1.2" fill="currentColor" stroke="none"/></symbol>
+    <symbol id="icon-satellite" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"><path d="M2 13.2 5.6 9.6"/><path d="M4.2 8.2a3.4 3.4 0 0 1 4.8 4.8z"/><path d="M9.2 6.6a3.2 3.2 0 0 1 2.6 2.6"/><path d="M9.8 3.6a6.2 6.2 0 0 1 5.2 5.2"/></symbol>
     <symbol id="icon-stats" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"><path d="M2 14h12"/><rect x="3" y="8" width="2" height="6" rx="0.4" fill="currentColor" stroke="none" opacity="0.6"/><rect x="7" y="5" width="2" height="9" rx="0.4" fill="currentColor" stroke="none" opacity="0.75"/><rect x="11" y="2" width="2" height="12" rx="0.4" fill="currentColor" stroke="none" opacity="0.9"/></symbol>
     <symbol id="icon-record" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><circle cx="8" cy="8" r="6"/><circle cx="8" cy="8" r="2.5" fill="currentColor" stroke="none"/></symbol>
     <symbol id="icon-settings" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"><path d="M9.8 3.1a2.6 2.6 0 0 0-2.2 3.9L3.4 11.2a1.2 1.2 0 1 0 1.7 1.7l4.2-4.2a2.6 2.6 0 0 0 3.9-2.2l-1.8.6-1.2-1.2z"/><path d="M10.2 5.8 12 4"/></symbol>
@@ -52,14 +53,21 @@ SPDX-License-Identifier: GPL-2.0-or-later
             <svg class="tab-icon" aria-hidden="true"><use href="#icon-bookmark"/></svg>
             <span class="tab-label">Bookmarks</span>
           </button>
-          <button class="tab" data-tab="digital-modes">
+          <button class="tab" data-tab="digital-modes" aria-label="Digital modes">
             <svg class="tab-icon" aria-hidden="true"><use href="#icon-digital"/></svg>
             <span class="tab-label">Digital modes</span>
+            <!-- A fifth of a phone screen does not hold "Digital modes"; the
+                 button keeps the full name for assistive tech. -->
+            <span class="tab-label-short" aria-hidden="true">Digital</span>
           </button>
           <button class="tab" data-tab="map">
             <svg class="tab-icon" aria-hidden="true"><use href="#icon-map"/></svg>
             <span class="tab-label">Map</span>
           </button>
+          <button class="tab" data-tab="satellites">
+            <svg class="tab-icon" aria-hidden="true"><use href="#icon-satellite"/></svg>
+            <span class="tab-label">Satellites</span>
+          </button>
           <button class="tab" data-tab="statistics">
             <svg class="tab-icon" aria-hidden="true"><use href="#icon-stats"/></svg>
             <span class="tab-label">Statistics</span>
@@ -163,13 +171,14 @@ SPDX-License-Identifier: GPL-2.0-or-later
         <div id="spectrum-size-grip" title="Drag to resize spectrum height" aria-label="Resize spectrum height"></div>
         <div id="spectrum-controls">
           <div id="spectrum-bw-row">
-            <label id="spectrum-bw-label">Bandwidth <input type="number" id="spectrum-bw-input" value="" step="0.1" min="0.1" /> kHz</label>
-            <button id="spectrum-bw-set-btn" type="button">Set</button>
-            <button id="spectrum-bw-auto-btn" type="button">Auto BW</button>
-            <button id="spectrum-bw-sweet-btn" type="button">Sweet-spot</button>
+            <label id="spectrum-bw-label" class="spectrum-field"><span class="spectrum-field-name">Bandwidth</span><input type="number" id="spectrum-bw-input" value="" step="0.1" min="0.1" /><span class="spectrum-field-unit">kHz</span></label>
+            <button id="spectrum-bw-set-btn" class="spectrum-btn" type="button">Set</button>
+            <button id="spectrum-bw-auto-btn" class="spectrum-btn" type="button">Auto BW</button>
+            <button id="spectrum-bw-sweet-btn" class="spectrum-btn" type="button">Sweet-spot</button>
           </div>
+          <div class="spectrum-controls-spacer" aria-hidden="true"></div>
           <div id="spectrum-level-row">
-            <label class="overview-control" id="spectrum-peak-hold-label">Peak Hold
+            <label class="overview-control spectrum-field" id="spectrum-peak-hold-label"><span class="spectrum-field-name">Peak Hold</span>
               <select id="overview-peak-hold" class="status-input">
                 <option value="0">Off</option>
                 <option value="500">0.5 s</option>
@@ -182,10 +191,10 @@ SPDX-License-Identifier: GPL-2.0-or-later
                 <option value="60000">60 s</option>
               </select>
             </label>
-            <label id="spectrum-floor-label">Floor <input type="number" id="spectrum-floor-input" value="-115" step="5" /> dB</label>
-            <label id="spectrum-range-label">Range <input type="number" id="spectrum-range-input" value="90" step="10" min="10" /> dB</label>
-            <button id="spectrum-auto-btn" type="button">Auto</button>
-            <label id="spectrum-gamma-label">Contrast <input type="range" id="spectrum-gamma-input" min="0.2" max="3.0" step="0.1" value="1.0" /><span id="spectrum-gamma-value">1.0</span></label>
+            <label id="spectrum-floor-label" class="spectrum-field"><span class="spectrum-field-name">Floor</span><input type="number" id="spectrum-floor-input" value="-115" step="5" /><span class="spectrum-field-unit">dB</span></label>
+            <label id="spectrum-range-label" class="spectrum-field"><span class="spectrum-field-name">Range</span><input type="number" id="spectrum-range-input" value="90" step="10" min="10" /><span class="spectrum-field-unit">dB</span></label>
+            <button id="spectrum-auto-btn" class="spectrum-btn" type="button">Auto</button>
+            <label id="spectrum-gamma-label" class="spectrum-field"><span class="spectrum-field-name">Contrast</span><input type="range" id="spectrum-gamma-input" min="0.2" max="3.0" step="0.1" value="1.0" /><span id="spectrum-gamma-value" class="spectrum-field-value">1.0</span></label>
           </div>
         </div>
         <div id="spectrum-hint" class="spectrum-hint-mouse">Scroll to zoom &middot; Ctrl+Scroll to tune &middot; Drag to pan &middot; Drag BW edges to resize &middot; +/- zoom &middot; Arrows pan &middot; 0 reset</div>
@@ -584,6 +593,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
         <button class="sub-tab" data-subtab="rds">RDS</button>
         <button class="sub-tab" data-subtab="sat">SAT</button>
         <button class="sub-tab" data-subtab="wefax">WEFAX</button>
+        <button class="sub-tab" data-subtab="sstv">SSTV</button>
       </div>
       <div id="subtab-overview" class="sub-tab-panel">
         <div class="plugin-item" data-decoder="ais">
@@ -646,6 +656,12 @@ SPDX-License-Identifier: GPL-2.0-or-later
             Decodes Meteor-M LRPT (137 MHz QPSK) weather satellite imagery.
           </div>
         </div>
+        <div class="plugin-item" data-decoder="sstv">
+          <strong>SSTV Decoder</strong>
+          <div style="color:var(--text-muted); font-size:0.85rem; margin-top:0.2rem;">
+            Slow-Scan Television &mdash; pictures in Martin, Scottie, Robot, PD and Wraase modes
+          </div>
+        </div>
         <div class="plugin-item" data-decoder="wefax">
           <strong>WEFAX Decoder</strong>
           <div style="color:var(--text-muted); font-size:0.85rem; margin-top:0.2rem;">
@@ -653,6 +669,56 @@ SPDX-License-Identifier: GPL-2.0-or-later
           </div>
         </div>
       </div>
+      <div id="subtab-sstv" class="sub-tab-panel" style="display:none;">
+        <div class="ft8-controls">
+          <button id="sstv-decode-toggle-btn" type="button">Enable SSTV</button>
+          <small id="sstv-status" style="color:var(--text-muted);">Idle</small>
+        </div>
+        <!-- View selector -->
+        <div class="sat-view-bar">
+          <button id="sstv-view-live" class="sat-view-btn sat-view-active" type="button">Live</button>
+          <button id="sstv-view-history" class="sat-view-btn" type="button">History</button>
+        </div>
+        <!-- Live view -->
+        <div id="sstv-live-view">
+          <div style="margin:0 0 0.5rem;">
+            <div style="color:var(--text-muted); font-size:0.82rem; line-height:1.5;">
+              <strong>Slow-Scan Television</strong> &mdash; pictures sent as tones, in Martin,
+              Scottie, Robot, PD and Wraase modes. Tune a sideband or FM signal and enable the
+              decoder; the mode is read from the header the sender opens with.
+            </div>
+          </div>
+          <div id="sstv-live-container" style="display:none; margin:0.5rem 0;">
+            <div style="display:flex; align-items:center; gap:0.5rem; margin-bottom:0.3rem;">
+              <strong>Receiving</strong>
+              <small id="sstv-live-info" style="color:var(--text-muted);"></small>
+            </div>
+            <canvas id="sstv-live-canvas" width="320" height="256"
+                    style="width:100%; max-width:640px; image-rendering:pixelated; background:#111;"></canvas>
+          </div>
+          <div id="sstv-live-latest" style="margin-top:0.5rem;"></div>
+        </div>
+        <!-- History view -->
+        <div id="sstv-history-view" style="display:none;">
+          <div class="sat-history-controls">
+            <input id="sstv-filter" class="ft8-filter" type="text" placeholder="Filter (e.g. Martin, PD120)" />
+            <select id="sstv-sort" class="sat-sort-select">
+              <option value="newest">Newest first</option>
+              <option value="oldest">Oldest first</option>
+            </select>
+            <button id="sstv-clear-btn" type="button" style="font-size:0.8rem;">Clear All</button>
+          </div>
+          <div class="sat-history-header">
+            <span class="sat-col-time">Time</span>
+            <span class="sat-col-type">Mode</span>
+            <span class="sat-col-sat">Size</span>
+            <span class="sat-col-lines">Lines</span>
+            <span class="sat-col-link">Image</span>
+          </div>
+          <div id="sstv-history-list"></div>
+          <small id="sstv-history-count" style="color:var(--text-muted);font-size:0.75rem;">No pictures yet</small>
+        </div>
+      </div>
       <div id="subtab-rds" class="sub-tab-panel" style="display:none;">
         <div class="rds-grid">
           <div class="rds-field"><span class="rds-label">Status</span><span id="rds-status" class="rds-value rds-no-signal">No signal</span></div>
@@ -857,7 +923,6 @@ SPDX-License-Identifier: GPL-2.0-or-later
         <div class="sat-view-bar">
           <button id="sat-view-live" class="sat-view-btn sat-view-active" type="button">Live</button>
           <button id="sat-view-history" class="sat-view-btn" type="button">History</button>
-          <button id="sat-view-predictions" class="sat-view-btn" type="button">Predictions</button>
         </div>
         <!-- Live view -->
         <div id="sat-live-view">
@@ -899,50 +964,6 @@ SPDX-License-Identifier: GPL-2.0-or-later
           <div id="sat-history-list"></div>
           <small id="sat-history-count" style="color:var(--text-muted);font-size:0.75rem;">No images yet</small>
         </div>
-        <!-- Predictions view -->
-        <div id="sat-predictions-view" style="display:none;">
-          <div class="ft8-controls">
-            <input id="sat-pred-filter" class="ft8-filter" type="text" placeholder="Filter (e.g. ISS, NOAA, Meteor)" />
-            <select id="sat-pred-category" class="sat-sort-select">
-              <option value="all">All</option>
-              <option value="weather">Weather</option>
-              <option value="amateur">Ham Radio</option>
-              <option value="other">Other</option>
-            </select>
-            <select id="sat-pred-min-el" class="sat-sort-select">
-              <option value="0">All passes</option>
-              <option value="10">Min 10°</option>
-              <option value="20">Min 20°</option>
-              <option value="45">Min 45°</option>
-            </select>
-          </div>
-          <!-- Current passes -->
-          <div id="sat-pred-current-section">
-            <div class="sat-pred-section-title">Currently receivable</div>
-            <div class="sat-pred-header sat-pred-header-current">
-              <span class="sat-pred-col-sat">Satellite</span>
-              <span class="sat-pred-col-el">Max El</span>
-              <span class="sat-pred-col-time">AOS Start</span>
-              <span class="sat-pred-col-time">AOS End</span>
-              <span class="sat-pred-col-countdown">Time left</span>
-              <span class="sat-pred-col-dir">Direction</span>
-            </div>
-            <div id="sat-pred-current-list"></div>
-          </div>
-          <!-- Upcoming passes -->
-          <div id="sat-pred-upcoming-section">
-            <div class="sat-pred-section-title">Upcoming passes</div>
-            <div class="sat-pred-header">
-              <span class="sat-pred-col-time">AOS (UTC)</span>
-              <span class="sat-pred-col-sat">Satellite</span>
-              <span class="sat-pred-col-el">Max El</span>
-              <span class="sat-pred-col-dur">Duration</span>
-              <span class="sat-pred-col-dir">Direction</span>
-            </div>
-            <div id="sat-pred-list"></div>
-          </div>
-          <small id="sat-pred-status" style="color:var(--text-muted);font-size:0.75rem;">Loading predictions&hellip;</small>
-        </div>
       </div>
       <div id="subtab-wefax" class="sub-tab-panel" style="display:none;">
         <div class="ft8-controls">
@@ -1056,6 +1077,51 @@ SPDX-License-Identifier: GPL-2.0-or-later
       </div>
       </template>
     </div>
+    <div id="tab-satellites" class="tab-panel" style="display:none;">
+      <h2 class="section-heading">Satellites</h2>
+      <div class="ft8-controls">
+        <input id="sat-pred-filter" class="ft8-filter" type="text" placeholder="Filter (e.g. ISS, NOAA, Meteor)" />
+        <select id="sat-pred-category" class="sat-sort-select">
+          <option value="all">All</option>
+          <option value="weather">Weather</option>
+          <option value="amateur">Ham Radio</option>
+          <option value="other">Other</option>
+        </select>
+        <select id="sat-pred-min-el" class="sat-sort-select">
+          <option value="0">All passes</option>
+          <option value="10">Min 10°</option>
+          <option value="20">Min 20°</option>
+          <option value="45">Min 45°</option>
+        </select>
+      </div>
+      <!-- Current passes -->
+      <div id="sat-pred-current-section">
+        <div class="sat-pred-section-title">Currently receivable</div>
+        <div class="sat-pred-header sat-pred-header-current">
+          <span class="sat-pred-col-sat">Satellite</span>
+          <span class="sat-pred-col-el">Max El</span>
+          <span class="sat-pred-col-time">AOS Start</span>
+          <span class="sat-pred-col-time">AOS End</span>
+          <span class="sat-pred-col-countdown">Time left</span>
+          <span class="sat-pred-col-dir">Direction</span>
+        </div>
+        <div id="sat-pred-current-list"></div>
+      </div>
+      <!-- Upcoming passes -->
+      <div id="sat-pred-upcoming-section">
+        <div class="sat-pred-section-title">Upcoming passes</div>
+        <div class="sat-pred-header">
+          <span class="sat-pred-col-time">AOS (UTC)</span>
+          <span class="sat-pred-col-sat">Satellite</span>
+          <span class="sat-pred-col-el">Max El</span>
+          <span class="sat-pred-col-dur">Duration</span>
+          <span class="sat-pred-col-dir">Direction</span>
+        </div>
+        <div id="sat-pred-list"></div>
+      </div>
+      <small id="sat-pred-status" style="color:var(--text-muted);font-size:0.75rem;">Loading predictions&hellip;</small>
+    </div>
+
     <div id="tab-statistics" class="tab-panel" style="display:none;">
       <h2 class="section-heading">Statistics</h2>
       <template id="tmpl-statistics">

src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css

@@ -1717,6 +1717,8 @@ small { color: var(--text-muted); }
   flex-shrink: 0;
 }
 .tab-label { display: block; }
+/* Only the bottom nav is short of room. */
+.tab-label-short { display: none; }
 .tab-more-icon { display: none; }
 .about-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 1rem; }
 .about-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 0.5rem; padding: 0; overflow: hidden; }
@@ -2592,7 +2594,6 @@ button.map-qso-card:focus-visible {
   box-shadow: 0 16px 30px rgba(0, 0, 0, 0.24);
   backdrop-filter: blur(6px);
   -webkit-backdrop-filter: blur(6px);
-  will-change: backdrop-filter;
   overflow: auto;
   transition: opacity 140ms ease, transform 140ms ease, visibility 140ms ease;
 }
@@ -2610,9 +2611,15 @@ button.map-qso-card:focus-visible {
 .map-overlay-filters.is-hidden {
   display: none;
 }
-/* With the filters collapsed the bar has no reason to span the map. */
+/* With the filters collapsed the bar has no reason to span the map.
+   It keeps both anchors and shrinks inside them, rather than dropping `left`
+   and being sized by shrink-to-fit: the anchored box is a size the browser
+   already knows, and an absolutely positioned, backdrop-filtered, composited
+   box being asked to size itself from its content is the shape of thing that
+   renders as nothing on engines other than the one it was written against. */
 .map-overlay-panel.filters-hidden {
-  left: auto;
+  width: fit-content;
+  margin-left: auto;
 }
 .map-overlay-actions {
   display: flex;
@@ -2739,7 +2746,6 @@ button.map-qso-card:focus-visible {
   box-shadow: 0 16px 30px rgba(0, 0, 0, 0.2);
   backdrop-filter: blur(6px);
   -webkit-backdrop-filter: blur(6px);
-  will-change: backdrop-filter;
   overflow: auto;
 }
 .map-band-legend.is-empty {
@@ -3810,11 +3816,12 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
 @media (max-width: 760px) {
   body[data-operator-layout="broadcast"] #wfm-controls-col { flex-basis: 100%; }
 }
-/* One navigation model at every width.  Statistics, Recorder, Settings and
- * About are occasional destinations: they live behind More rather than
- * competing with the operating tabs for the row and then scrolling out of
+/* One navigation model at every width.  Satellites, Statistics, Recorder,
+ * Settings and About are occasional destinations: they live behind More rather
+ * than competing with the operating tabs for the row and then scrolling out of
  * reach.  The mobile layout already grouped them this way; the desktop strip
  * now matches it, which is why the tab strip no longer needs to scroll. */
+.tab-bar-nav .tab[data-tab="satellites"],
 .tab-bar-nav .tab[data-tab="statistics"],
 .tab-bar-nav .tab[data-tab="recorder"],
 .tab-bar-nav .tab[data-tab="settings"],
@@ -3892,7 +3899,18 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
   input.status-input, select.status-input { font-size: 1.1rem; }
   :root { --header-waterfall-overlap: 0rem; }
   .controls-tray-scroll { overflow-x: auto; }
-  .controls-tray { width: 100%; min-width: 0; padding-left: 0.85rem; padding-right: 0.85rem; }
+  /* A grid column sizes to its content by default, so one row wider than the
+     phone — the mode picker, six buttons across — dragged the whole tray out
+     with it and left the rest to be found by scrolling sideways. `minmax(0,
+     1fr)` lets the column be as narrow as the screen and the rows wrap inside
+     it. */
+  .controls-tray {
+    width: 100%;
+    min-width: 0;
+    grid-template-columns: minmax(0, 1fr);
+    padding-left: 0.85rem;
+    padding-right: 0.85rem;
+  }
   .freq-inline { gap: 0.5rem; flex-wrap: wrap; }
   .header-text { width: auto; min-width: 0; flex: 0 1 auto; }
   .header-main {
@@ -4013,12 +4031,9 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
     box-shadow: inset 0 1px 0 color-mix(in srgb, #ffffff 8%, transparent);
   }
   .tab-icon, .tab-more-icon { display: block; }
-  /* Shorten long tab labels to keep bottom nav compact */
-  .tab[data-tab="bookmarks"] .tab-label { font-size: 0.6rem; }
-  .tab[data-tab="digital-modes"] .tab-label  { font-size: 0.6rem; }
-  .tab[data-tab="statistics"] .tab-label { font-size: 0.6rem; }
-  .tab[data-tab="statistics"], .tab[data-tab="recorder"],
-  .tab[data-tab="settings"], .tab[data-tab="about"] { display: none; }
+  .tab[data-tab="satellites"], .tab[data-tab="statistics"],
+  .tab[data-tab="recorder"], .tab[data-tab="settings"],
+  .tab[data-tab="about"] { display: none; }
   .mobile-more-btn { display: flex; }
   .mobile-more-menu {
     position: fixed;
@@ -4030,7 +4045,48 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
     color: var(--accent-text);
     background: color-mix(in srgb, var(--accent-green) 10%, transparent);
   }
-  .tab .tab-label, .tab[data-tab] .tab-label { font-size: 0.75rem; }
+  /* The bottom nav divides the bar between its five destinations, so a tab is
+     about a fifth of the screen and the label has to live inside that. Sharing
+     the width evenly beats sizing each tab to its own label, which gave
+     "Digital modes" the same room as "Map" and clipped it mid-word. */
+  .tab-bar-nav .tab {
+    flex: 1 1 0;
+    min-width: 0;
+    padding-left: 0.15rem;
+    padding-right: 0.15rem;
+  }
+  .tab .tab-label, .tab[data-tab] .tab-label {
+    display: block;
+    max-width: 100%;
+    overflow: hidden;
+    white-space: nowrap;
+    text-overflow: ellipsis;
+    font-size: 0.75rem;
+  }
+  /* The long ones, sized against the screen rather than at a fixed size.
+     A tab is a fifth of the viewport, so what fits in it is a function of the
+     viewport — and only roughly of the font size, since how wide a platform
+     renders a word varies by ten per cent or more between machines. A fixed
+     0.6rem fit here with ten pixels to spare and clipped in CI.
+
+     (These rules also used to sit above the one that sets the size for all
+     labels — identical specificity, later in the file, so nothing was ever
+     shortened.) */
+  .tab[data-tab="bookmarks"] .tab-label,
+  .tab[data-tab="statistics"] .tab-label {
+    font-size: clamp(0.46rem, 2.2vw, 0.62rem);
+  }
+  /* "Digital modes" does not fit at any size worth reading, so the nav shows
+     the short form and the button carries the full one as its label. */
+  .tab[data-tab="digital-modes"] .tab-label { display: none; }
+  .tab[data-tab="digital-modes"] .tab-label-short {
+    display: block;
+    max-width: 100%;
+    overflow: hidden;
+    white-space: nowrap;
+    text-overflow: ellipsis;
+    font-size: clamp(0.46rem, 2.2vw, 0.62rem);
+  }
   .decoder-tab-select {
     display: block;
     width: 100%;
@@ -4068,10 +4124,18 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
     flex: 0 0 auto;
     min-width: 0;
   }
+  /* The rig's name is the widest thing in the bar and it does not need to be:
+     139 px of a 338 px bar went on it, and everything else was pushed into the
+     overflow menu to make room. Enough for a short name, ellipsised past that,
+     with the full name still in the menu it opens. */
   .header-rig-switch select,
   .header-style-pick select {
     width: auto;
     min-width: 0;
+    max-width: 6.5rem;
+    padding-right: 0.2rem;
+    font-size: 0.8rem;
+    text-overflow: ellipsis;
   }
   .header-bar-btn {
     flex: 0 0 auto;
@@ -4102,12 +4166,20 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
   .mult-col {
     min-width: 0;
   }
+  /* These are given the width of their column below; with padding on a
+     content box that is the column's width *plus* the padding, which is what
+     pushed the page itself sideways by a dozen pixels. */
   .wavelength-display,
   .sig-strength-display,
   .jog-step,
   .jog-mult {
+    box-sizing: border-box;
     width: 100%;
   }
+  .sig-strength-display {
+    min-width: 0;
+    font-size: 1.05rem;
+  }
   .jog-step button,
   .jog-mult button {
     flex: 1 1 0;
@@ -4131,47 +4203,6 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
   .signal-measure #sig-result {
     width: 100%;
   }
-  #spectrum-controls {
-    flex-direction: column;
-    align-items: stretch;
-    gap: 0.45rem;
-    padding-top: 0.45rem;
-  }
-  #spectrum-bw-row,
-  #spectrum-level-row {
-    display: flex;
-    flex-wrap: wrap;
-    gap: 0.35rem 0.4rem;
-  }
-  #spectrum-bw-label,
-  #spectrum-floor-label,
-  #spectrum-range-label,
-  #spectrum-peak-hold-label {
-    flex: 1 1 100%;
-    justify-content: space-between;
-  }
-  #spectrum-gamma-label {
-    flex: 1 1 100%;
-    justify-content: space-between;
-  }
-  #spectrum-gamma-input {
-    flex: 1 1 auto;
-    min-width: 3rem;
-  }
-  #spectrum-bw-input,
-  #spectrum-floor-input,
-  #spectrum-range-input,
-  #overview-peak-hold {
-    flex: 1 1 auto;
-    min-width: 3rem;
-    box-sizing: border-box;
-  }
-  #spectrum-bw-set-btn,
-  #spectrum-bw-auto-btn,
-  #spectrum-bw-sweet-btn,
-  #spectrum-auto-btn {
-    flex: 1 1 auto;
-  }
   .spectrum-edge-shift {
     width: 0.95rem;
   }
@@ -4821,111 +4852,166 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
   white-space: nowrap;
   z-index: 10;
 }
+/* ── Spectrum control strip ────────────────────────────────────────────
+   Two clusters of controls under the plot: the receiver's bandwidth on the
+   left, the display's levels on the right.  Everything in here is one height
+   and one shape — a row whose controls each size themselves reads as a pile
+   rather than a strip.
+
+   The container wraps; a cluster does not.  A cluster that cannot fit drops
+   whole to the next line and starts it left-aligned, rather than splitting and
+   leaving the cluster beside it floating at a height of its own, which is what
+   the two rows did to each other between 1100 and 1400 px. */
 #spectrum-controls {
   display: flex;
   align-items: center;
-  justify-content: space-between;
+  flex-wrap: wrap;
   padding: 3px 4px 0;
-  gap: 0.6rem;
+  gap: 0.35rem 0.5rem;
   font-size: 0.78rem;
   color: var(--text-muted);
 }
-#spectrum-bw-row {
-  display: flex;
-  align-items: center;
-  flex-wrap: wrap;
-  gap: 0.4rem;
-}
-#spectrum-bw-label {
-  display: flex;
-  align-items: center;
-  gap: 0.3rem;
-  font-size: 0.75rem;
-  color: var(--text-muted);
-  min-width: 0;
-}
-#spectrum-bw-input {
-  width: 4.5rem;
-  padding: 1px 4px;
-  font-size: 0.75rem;
-  border: 1px solid var(--border);
-  border-radius: 4px;
-  background: var(--input-bg);
-  color: var(--text);
-  text-align: right;
-  height: 1.5rem;
-}
-#spectrum-bw-set-btn,
-#spectrum-bw-auto-btn,
-#spectrum-bw-sweet-btn {
-  height: 1.5rem;
-  min-height: 0;
-  padding: 0 8px;
-  font-size: 0.75rem;
-}
+#spectrum-bw-row,
 #spectrum-level-row {
   display: flex;
   align-items: center;
-  gap: 0.4rem;
+  flex-wrap: nowrap;
+  gap: 0.3rem;
 }
-#spectrum-floor-label {
-  display: flex;
+/* Takes the slack, so the clusters reach the ends of a wide strip without
+   `space-between` opening a quarter-width hole in the middle of it. */
+.spectrum-controls-spacer {
+  flex: 1 1 1.5rem;
+  min-width: 0;
+}
+
+/* A field is one box: name, value and unit share a border, so a number can
+   never be read apart from the unit it is in. */
+.spectrum-field {
+  display: inline-flex;
   align-items: center;
   gap: 0.3rem;
+  /* Border-box on both field and button, or the button's own border and
+     padding add to the height and the two end up a couple of pixels apart —
+     which is the pile-of-controls look this is meant to end. */
+  box-sizing: border-box;
+  height: 1.7rem;
+  padding: 0 0.4rem 0 0.5rem;
+  border: 1px solid var(--border-light);
+  border-radius: 6px;
+  background: var(--input-bg);
+  white-space: nowrap;
   font-size: 0.75rem;
   color: var(--text-muted);
 }
-#spectrum-floor-input {
-  width: 3.4rem;
-  padding: 1px 4px;
-  font-size: 0.75rem;
-  border: 1px solid var(--border);
-  border-radius: 4px;
-  background: var(--input-bg);
-  color: var(--text);
-  text-align: right;
-  height: 1.5rem;
+.spectrum-field:focus-within {
+  border-color: color-mix(in srgb, var(--accent-green) 45%, var(--border-light));
 }
-#spectrum-range-label {
-  display: flex;
-  align-items: center;
-  gap: 0.3rem;
-  font-size: 0.75rem;
+.spectrum-field-name {
+  font-size: 0.72rem;
   color: var(--text-muted);
 }
-#spectrum-range-input {
-  width: 3.4rem;
-  padding: 1px 4px;
-  font-size: 0.75rem;
-  border: 1px solid var(--border);
-  border-radius: 4px;
-  background: var(--input-bg);
+/* Unit and readout hold a fixed, tabular slot: the row must not twitch as a
+   value goes from 1.0 to 0.9. */
+.spectrum-field-unit,
+.spectrum-field-value {
+  font-size: 0.7rem;
+  color: var(--text-muted);
+  font-variant-numeric: tabular-nums;
+  min-width: 1.7rem;
+}
+.spectrum-field-value {
   color: var(--text);
   text-align: right;
-  height: 1.5rem;
 }
-#spectrum-auto-btn {
-  height: 1.5rem;
+.spectrum-field input[type="number"] {
+  width: 3.2rem;
+  padding: 0;
+  border: 0;
+  background: transparent;
+  color: var(--text);
+  font-size: 0.78rem;
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+}
+.spectrum-field input[type="number"]:focus {
+  outline: none;
+}
+#spectrum-bw-input {
+  width: 3.6rem;
+}
+/* The select carries `status-input` for the sake of other layouts, which gives
+   it a border and a background of its own; inside a field that reads as a box
+   drawn inside a box. */
+#spectrum-controls .spectrum-field select {
+  width: auto;
+  height: 1.35rem;
   min-height: 0;
-  padding: 0 8px;
-  font-size: 0.75rem;
+  padding: 0 0.1rem;
+  border: 0;
+  border-radius: 0;
+  background: transparent;
+  color: var(--text);
+  font-size: 0.74rem;
 }
-#spectrum-gamma-label {
-  display: flex;
-  align-items: center;
-  gap: 0.3rem;
-  font-size: 0.75rem;
-  color: var(--text-muted);
-}
-#spectrum-gamma-input {
-  width: 5rem;
-  height: 1.5rem;
+.spectrum-field input[type="range"] {
+  width: 5.5rem;
+  height: 1.2rem;
   cursor: pointer;
 }
-#spectrum-gamma-value {
-  font-size: 0.75rem;
-  min-width: 1.6rem;
-  text-align: right;
+.spectrum-btn {
+  box-sizing: border-box;
+  height: 1.7rem;
+  min-height: 0;
+  padding: 0 0.6rem;
+  border-radius: 6px;
+  font-size: 0.73rem;
+  font-weight: 600;
+  white-space: nowrap;
+}
+/* Fingers need more than a 27 px target; a mouse does not, and the strip has
+   no width to spare on a desktop. */
+@media (hover: none) and (pointer: coarse) {
+  .spectrum-field,
+  .spectrum-btn {
+    height: 2.4rem;
+  }
+}
+
+/* Narrow screens: the same fields, stacked. This sits after the rules it
+   overrides — `#spectrum-bw-row` in both places has identical specificity, so
+   whichever comes last wins, and from inside the earlier media query the
+   narrow rules silently lost. */
+@media (max-width: 640px) {
+  /* Narrow: the clusters stack, and a field takes the width so its name and
+     its value sit at opposite ends of a line the thumb can hit. */
+  #spectrum-controls {
+    flex-direction: column;
+    align-items: stretch;
+    gap: 0.45rem;
+    padding-top: 0.45rem;
+  }
+  #spectrum-bw-row,
+  #spectrum-level-row {
+    flex-wrap: wrap;
+    gap: 0.35rem 0.4rem;
+  }
+  .spectrum-controls-spacer {
+    display: none;
+  }
+  #spectrum-controls .spectrum-field {
+    flex: 1 1 100%;
+    justify-content: space-between;
+  }
+  #spectrum-controls .spectrum-field input[type="number"],
+  #spectrum-controls .spectrum-field input[type="range"],
+  #spectrum-controls .spectrum-field select {
+    flex: 1 1 auto;
+    min-width: 3rem;
+  }
+  #spectrum-controls .spectrum-btn {
+    flex: 1 1 auto;
+  }
 }
 .spectrum-hint-mouse,
 .spectrum-hint-touch {
@@ -4944,9 +5030,15 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
 
 /* ── Phone layout (≤ 520px) ───────────────────────────────────────────── */
 @media (max-width: 520px) {
-  /* Single-column controls: jog first, then mode, then power */
+  /* Single-column controls: jog first, then mode, then power.
+     `nowrap` is the whole point of it. The base rule wraps, and a *column*
+     that wraps starts a second column when its items are taller than it is —
+     which put the transmit controls at x=400 on a 390 px screen, off the side
+     of a tray 354 px wide, reachable only by a horizontal scroll with nothing
+     to say it was there. */
   .controls-row {
     flex-direction: column;
+    flex-wrap: nowrap;
     align-items: stretch;
   }
   .controls-col-center {
@@ -6135,8 +6227,16 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
 .controls-tray { container-type: inline-size; container-name: controls; }
 .decode-history-table-wrap { container-type: inline-size; container-name: decode-table; }
 
-@container controls (max-width: 600px) {
-  .controls-tray .controls-row { flex-wrap: wrap; }
+/* Wrapping a narrow tray's columns onto more lines is right while the row runs
+   left to right. Below the phone breakpoint the row is a column, and wrap there
+   means "start another column" — which is how the transmit controls ended up
+   beside the tray instead of under it, off the side of the screen. This rule
+   outranks the phone one (two classes to its one) and sits later in the file,
+   so it has to exclude itself rather than be overridden. */
+@media (min-width: 521px) {
+  @container controls (max-width: 600px) {
+    .controls-tray .controls-row { flex-wrap: wrap; }
+  }
 }
 @container decode-table (max-width: 500px) {
   .decode-history-table th:nth-child(n+4),

src/trx-client/trx-frontend/trx-frontend-http/frontend/build.mjs

@@ -23,12 +23,14 @@ await build({
     ft8: path.join(sourceDir, "plugins", "ft8.ts"),
     vdes: path.join(sourceDir, "plugins", "vdes.ts"),
     wefax: path.join(sourceDir, "plugins", "wefax.ts"),
+    sstv: path.join(sourceDir, "plugins", "sstv.ts"),
     "background-decode": path.join(sourceDir, "plugins", "background-decode.ts"),
     ais: path.join(sourceDir, "plugins", "ais.ts"),
     aprs: path.join(sourceDir, "plugins", "aprs.ts"),
     "hf-aprs": path.join(sourceDir, "plugins", "hf-aprs.ts"),
     sat: path.join(sourceDir, "plugins", "sat.ts"),
     "sat-scheduler": path.join(sourceDir, "plugins", "sat-scheduler.ts"),
+    "satellite-predictions": path.join(sourceDir, "plugins", "satellite-predictions.ts"),
     vchan: path.join(sourceDir, "plugins", "vchan.ts"),
     bookmarks: path.join(sourceDir, "plugins", "bookmarks.ts"),
     scheduler: path.join(sourceDir, "plugins", "scheduler.ts"),

src/trx-client/trx-frontend/trx-frontend-http/frontend/package.json

@@ -12,7 +12,7 @@
     "typecheck": "tsc --project tsconfig.json && tsc --project tsconfig.worker.json",
     "lint": "eslint \"src/**/*.ts\" \"tests/**/*.mjs\" build.mjs --no-error-on-unmatched-pattern",
     "test": "node --test tests/*.test.mjs",
-    "test:browser": "node tests/browser-smoke.mjs && node tests/spectrum-layout.mjs && node tests/decode-flow.mjs && node tests/tune-links.mjs",
+    "test:browser": "node tests/browser-smoke.mjs && node tests/spectrum-layout.mjs && node tests/decode-flow.mjs && node tests/tune-links.mjs && node tests/mobile-layout.mjs && node tests/satellite-predictions.mjs",
     "verify-generated": "npm run generate-types && npm run build && git diff --exit-code -- ../assets/web/generated src/api/generated.ts"
   },
   "devDependencies": {

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/api/generated.ts

@@ -51,7 +51,7 @@ export type RigRxStatus = { sig: number | null, };
 
 export type RigStatus = { freq: Freq, mode: RigMode, tx_en: boolean, vfo: RigVfo | null, tx: RigTxStatus | null, rx: RigRxStatus | null, lock: boolean | null, };
 
-export type DecoderConfig = { aprs_decode_enabled: boolean, hf_aprs_decode_enabled: boolean, cw_decode_enabled: boolean, ft8_decode_enabled: boolean, ft4_decode_enabled: boolean, ft2_decode_enabled: boolean, wspr_decode_enabled: boolean, lrpt_decode_enabled: boolean, wefax_decode_enabled: boolean, recorder_enabled: boolean, };
+export type DecoderConfig = { aprs_decode_enabled: boolean, hf_aprs_decode_enabled: boolean, cw_decode_enabled: boolean, ft8_decode_enabled: boolean, ft4_decode_enabled: boolean, ft2_decode_enabled: boolean, wspr_decode_enabled: boolean, lrpt_decode_enabled: boolean, wefax_decode_enabled: boolean, sstv_decode_enabled: boolean, recorder_enabled: boolean, };
 
 export type WfmDenoiseLevel = "off" | "auto" | "low" | "medium" | "high";
 
@@ -111,7 +111,7 @@ export type RigSnapshot = { info: RigInfo, status: RigStatus, band: string | nul
 /**
  * Per-virtual-channel RDS snapshots, when available.
  */
-vchan_rds?: Array<VchanRdsEntry> | null, aprs_decode_enabled: boolean, hf_aprs_decode_enabled: boolean, cw_decode_enabled: boolean, ft8_decode_enabled: boolean, ft4_decode_enabled: boolean, ft2_decode_enabled: boolean, wspr_decode_enabled: boolean, lrpt_decode_enabled: boolean, wefax_decode_enabled: boolean, recorder_enabled: boolean, };
+vchan_rds?: Array<VchanRdsEntry> | null, aprs_decode_enabled: boolean, hf_aprs_decode_enabled: boolean, cw_decode_enabled: boolean, ft8_decode_enabled: boolean, ft4_decode_enabled: boolean, ft2_decode_enabled: boolean, wspr_decode_enabled: boolean, lrpt_decode_enabled: boolean, wefax_decode_enabled: boolean, sstv_decode_enabled: boolean, recorder_enabled: boolean, };
 
 export type RigListItem = { remote: string, display_name: string | null, manufacturer: string, model: string, supported_modes: Array<RigMode>, tx: boolean, filter_controls: boolean, initialized: boolean, latitude: number | null, longitude: number | null, };
 

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.ts

@@ -385,7 +385,9 @@ declare global {
     refreshCwTonePicker?(): void;
     updateFt8RfDisplay?(): void;
     clearSatPredictionDom?(): void;
+    refreshSatPredictions?(): void;
     syncWefaxToggle?(enabled: boolean): void;
+    syncSstvToggle?(enabled: boolean): void;
     updateAisBar?(value?: number): void;
     updateVdesBar?(value?: number): void;
     updateAprsBar?(value?: number): void;
@@ -858,7 +860,7 @@ function currentDecodeHistoryRetentionMs() {
 window.getDecodeHistoryRetentionMs = currentDecodeHistoryRetentionMs;
 
 window.applyDecodeHistoryRetention = function() {
-  for (const decoder of ["aprs", "hf_aprs", "ais", "vdes", "ft8", "ft4", "ft2", "wspr", "wefax"]) {
+  for (const decoder of ["aprs", "hf_aprs", "ais", "vdes", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"]) {
     window.trxPluginRuntime.prune(decoder);
   }
 };
@@ -3712,7 +3714,11 @@ function render(update: AppUpdate) {
   for (const [key, entry] of Object.entries(_decoderToggles)) {
     syncDecoderToggle(entry, !!update[key], entry.label);
   }
-  // WEFAX toggle sync (plugin-owned, belt-and-suspenders alongside _decoderToggles).
+  // Image decoders own their own toggle buttons; keep them in step with the
+  // rig state as well as with the click that set it.
+  if (typeof update.sstv_decode_enabled === "boolean" && window.syncSstvToggle) {
+    window.syncSstvToggle(update.sstv_decode_enabled);
+  }
   if (typeof update.wefax_decode_enabled === "boolean" && window.syncWefaxToggle) {
     window.syncWefaxToggle(update.wefax_decode_enabled);
   }
@@ -4844,6 +4850,7 @@ function _initMapWhenReady() {
 
 function navigateToTab(name: TabName, options: { updateHistory?: boolean; replaceHistory?: boolean } = {}) {
   window.trxUi?.closeMobileOverlays?.();
+  const leavingSatellites = _activeTab === "satellites" && name !== "satellites";
   const { updateHistory = true, replaceHistory = false } = options;
   if (authEnabled && !authRole && name !== "main") {
     showAuthGate(false);
@@ -4884,7 +4891,13 @@ function navigateToTab(name: TabName, options: { updateHistory?: boolean; replac
     updateTabHistory(name, replaceHistory);
   }
   scheduleSpectrumLayout();
-  void loadPluginsForTab(name).catch((error: unknown) => { console.error(error); });
+  // Its countdowns tick every second, so the page stops when it is not on screen.
+  if (leavingSatellites) window.clearSatPredictionDom?.();
+  void loadPluginsForTab(name).then(() => {
+    // Passes go stale while the page is closed, so each visit reloads them.
+    // The first visit is what imports the module, which renders on its own.
+    if (name === "satellites") window.refreshSatPredictions?.();
+  }).catch((error: unknown) => { console.error(error); });
   if (name === "map") {
     _initMapWhenReady();
   }
@@ -5236,10 +5249,6 @@ function _wireSubTabBar(bar: WiredElement) {
         if (window.refreshCwTonePicker) window.refreshCwTonePicker();
       });
     }
-    // Clear SAT prediction DOM when leaving the SAT tab to reduce node count.
-    if (btn.dataset.subtab !== "sat" && typeof window.clearSatPredictionDom === "function") {
-      window.clearSatPredictionDom();
-    }
   });
 }
 document.querySelectorAll<WiredElement>(".sub-tab-bar").forEach(_wireSubTabBar);
@@ -6567,9 +6576,15 @@ function updateDecodeStatus(text: string) {
     if (el && el.textContent !== "Receiving") el.textContent = text;
   }
 }
+// Picture decoders produce one message per image and a stream of progress
+// updates; neither is a spot, and counting them would swamp the statistics.
+const IMAGE_DECODE_KINDS = new Set([
+  "lrpt_image", "lrpt_progress", "wefax", "wefax_progress", "sstv", "sstv_progress",
+]);
+
 function dispatchDecodeMessage(msg: DecodeMessage, skipStats = false) {
   if (msg.type) window.trxPluginRuntime.dispatch(msg.type, msg);
-  if (!skipStats && msg.type && msg.type !== "lrpt_image" && msg.type !== "lrpt_progress" && msg.type !== "wefax" && msg.type !== "wefax_progress") {
+  if (!skipStats && msg.type && !IMAGE_DECODE_KINDS.has(msg.type)) {
     window.trx.modules.map?.statsRecordDecode(msg.type, msg.rig_id || msg.remote || null);
     window.trx.modules.map?.scheduleStatsRender();
   }
@@ -6619,7 +6634,7 @@ function loadDecodeHistoryOnMainThread(onReady: (groups: DecodeHistoryGroups) =>
 function restoreDecodeHistoryGroup(kind: string, messages: DecodeMessage[]) {
   if (!Array.isArray(messages) || messages.length === 0) return;
   // Record statistics for restored history messages.
-  if (kind !== "lrpt_image" && kind !== "lrpt_progress" && kind !== "wefax" && kind !== "wefax_progress") {
+  if (!IMAGE_DECODE_KINDS.has(kind)) {
     for (const msg of messages) {
       window.trx.modules.map?.statsRecordDecode(kind, msg.rig_id || msg.remote || null, msg.ts_ms || undefined);
     }

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/decode-history-worker.ts

@@ -5,7 +5,7 @@
 export {};
 
 const textDecoder = typeof TextDecoder === "function" ? new TextDecoder() : null;
-const HISTORY_GROUP_KEYS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax"] as const;
+const HISTORY_GROUP_KEYS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"] as const;
 type HistoryGroup = (typeof HISTORY_GROUP_KEYS)[number];
 type CborValue = number | string | boolean | null | undefined | CborValue[] | { [key: string]: CborValue };
 interface DecodeState { offset: number }

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/features/navigation/routes.ts

@@ -3,7 +3,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 export const TAB_ORDER = [
-  "main", "bookmarks", "digital-modes", "map", "statistics", "recorder", "settings", "about",
+  "main", "bookmarks", "digital-modes", "map", "satellites", "statistics", "recorder", "settings", "about",
 ] as const;
 
 export type TabName = typeof TAB_ORDER[number];
@@ -13,6 +13,7 @@ export const TAB_PATHS: Readonly<Record<TabName, string>> = {
   bookmarks: "/bookmarks",
   "digital-modes": "/digital-modes",
   map: "/map",
+  satellites: "/satellites",
   statistics: "/statistics",
   recorder: "/recorder",
   settings: "/settings",

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugin-loader.ts

@@ -2,7 +2,9 @@
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-type PluginGroup = "digital-modes" | "map-data" | "map" | "statistics" | "bookmarks" | "recorder" | "settings";
+type PluginGroup =
+  | "digital-modes" | "map-data" | "map" | "satellites" | "statistics"
+  | "bookmarks" | "recorder" | "settings";
 
 const pluginGroups: Readonly<Record<PluginGroup, readonly string[]>> = {
   // AIS, VDES and the two APRS decoders have panels on this tab, so they load
@@ -11,10 +13,11 @@ const pluginGroups: Readonly<Record<PluginGroup, readonly string[]>> = {
   // the Map tab. Their map calls are optional, so map-core stays lazy.
   "digital-modes": [
     "/ft8.js", "/ft4.js", "/ft2.js", "/wspr.js", "/cw.js", "/background-decode.js",
-    "/sat.js", "/wefax.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js",
+    "/sat.js", "/wefax.js", "/sstv.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js",
   ],
   "map-data": ["/map-core.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js"],
   map: ["/map-core.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js", "/sat.js", "/sat-scheduler.js"],
+  satellites: ["/satellite-predictions.js"],
   statistics: ["/map-core.js"],
   bookmarks: ["/bookmarks.js"],
   recorder: [],

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugins/sat.ts

@@ -4,13 +4,12 @@
 
 import { hostCore } from "./host.js";
 
-import type { LrptProgress, SatelliteImage, SatelliteLiveUpdate, SatellitePass, SatellitePassResponse } from "./satellite-types";
+import type { LrptProgress, SatelliteImage, SatelliteLiveUpdate } from "./satellite-types";
 import type { PluginRuntimeWindow } from "./runtime-contract.js";
 
-type SatelliteView = "live" | "history" | "predictions";
+type SatelliteView = "live" | "history";
 interface SatelliteBridge {
   trxScheduleUiFrameJob?: (key: string, job: () => void) => void;
-  clearSatPredictionDom?: () => void;
   updateSatLiveState?: (update: SatelliteLiveUpdate) => void;
   addSatMapOverlay?: (image: SatelliteImage) => void;
   clearSatMapOverlays?: () => void;
@@ -25,14 +24,14 @@ const satWindow = window as unknown as SatelliteBridge & PluginRuntimeWindow;
 // --- SAT Plugin ---
 // Live view: decoder state, latest image card
 // History view: filterable table of all decoded images
-// Predictions view: next 24 h passes for ham satellites
+//
+// Pass predictions live on their own page; see satellite-predictions.ts.
 
 // ── DOM references (cached once) ───────────────────────────────────
 const satDom = {
   status:           document.getElementById("sat-status"),
   liveView:         document.getElementById("sat-live-view"),
   historyView:      document.getElementById("sat-history-view"),
-  predictionsView:  document.getElementById("sat-predictions-view"),
   liveLatest:       document.getElementById("sat-live-latest"),
   historyList:      document.getElementById("sat-history-list"),
   historyCount:     document.getElementById("sat-history-count"),
@@ -42,30 +41,13 @@ const satDom = {
   lrptState:        document.getElementById("sat-lrpt-state"),
   viewLiveBtn:      document.getElementById("sat-view-live"),
   viewHistoryBtn:   document.getElementById("sat-view-history"),
-  viewPredBtn:      document.getElementById("sat-view-predictions"),
-  predFilter:       document.getElementById("sat-pred-filter") as HTMLInputElement | null,
-  predMinEl:        document.getElementById("sat-pred-min-el") as HTMLSelectElement | null,
-  predCategory:     document.getElementById("sat-pred-category") as HTMLSelectElement | null,
-  predCurrentList:  document.getElementById("sat-pred-current-list"),
-  predUpcomingList: document.getElementById("sat-pred-list"),
-  predCurrentSec:   document.getElementById("sat-pred-current-section"),
-  predUpcomingSec:  document.getElementById("sat-pred-upcoming-section"),
-  predStatus:       document.getElementById("sat-pred-status"),
 };
 
 // ── State ───────────────────────────────────────────────────────────
 let satImageHistory: SatelliteImage[] = [];
 const SAT_MAX_IMAGES = 100;
-const SAT_PRED_PAGE_SIZE = 50;
-let satPredShowAll = false;
 let satFilterText = "";
 let satActiveView: SatelliteView = "live";
-let satPredData: SatellitePass[] = [];
-let satPredFilterText = "";
-let satPredMinEl = 0;
-let satPredCategory = "all";
-let satPredSatCount = 0;
-let satPredCountdownTimer: ReturnType<typeof setInterval> | null = null;
 
 // ── UI scheduler helper ─────────────────────────────────────────────
 function scheduleSatUi(key: string, job: () => void): void {
@@ -78,33 +60,16 @@ function scheduleSatUi(key: string, job: () => void): void {
 
 // ── View switching ──────────────────────────────────────────────────
 function switchSatView(view: SatelliteView): void {
-  const leavingPredictions = satActiveView === "predictions" && view !== "predictions";
   satActiveView = view;
-  if (satDom.liveView)        satDom.liveView.style.display = view === "live" ? "" : "none";
-  if (satDom.historyView)     satDom.historyView.style.display = view === "history" ? "" : "none";
-  if (satDom.predictionsView) satDom.predictionsView.style.display = view === "predictions" ? "" : "none";
-  if (satDom.viewLiveBtn)     satDom.viewLiveBtn.classList.toggle("sat-view-active", view === "live");
-  if (satDom.viewHistoryBtn)  satDom.viewHistoryBtn.classList.toggle("sat-view-active", view === "history");
-  if (satDom.viewPredBtn)     satDom.viewPredBtn.classList.toggle("sat-view-active", view === "predictions");
-  if (leavingPredictions) clearPredictionDom();
-  if (view === "history") {
-    renderSatHistoryTable();
-  } else if (view === "predictions") {
-    satPredShowAll = false;
-    void loadSatPredictions();
-  }
+  if (satDom.liveView)       satDom.liveView.style.display = view === "live" ? "" : "none";
+  if (satDom.historyView)    satDom.historyView.style.display = view === "history" ? "" : "none";
+  if (satDom.viewLiveBtn)    satDom.viewLiveBtn.classList.toggle("sat-view-active", view === "live");
+  if (satDom.viewHistoryBtn) satDom.viewHistoryBtn.classList.toggle("sat-view-active", view === "history");
+  if (view === "history") renderSatHistoryTable();
 }
 
-function clearPredictionDom() {
-  stopCountdownTimer();
-  if (satDom.predCurrentList)  satDom.predCurrentList.innerHTML = "";
-  if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-}
-satWindow.clearSatPredictionDom = clearPredictionDom;
-
 satDom.viewLiveBtn?.addEventListener("click", () => { switchSatView("live"); });
 satDom.viewHistoryBtn?.addEventListener("click", () => { switchSatView("history"); });
-satDom.viewPredBtn?.addEventListener("click", () => { switchSatView("predictions"); });
 
 // ── Live view: decoder state ────────────────────────────────────────
 let lastSatLrptOn: boolean | null = null;
@@ -335,234 +300,6 @@ document
     }
   })(); });
 
-// ── Predictions: helpers ────────────────────────────────────────────
-function azToCardinal(deg: number): string {
-  const dirs = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
-  return dirs[Math.round(deg / 45) % 8] ?? "N";
-}
-
-function formatPredTime(ms: number): string {
-  const d = new Date(ms);
-  const now = new Date();
-  const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
-  const day = d.getUTCDay() !== now.getUTCDay() ? `${dayNames[d.getUTCDay()] ?? ""} ` : "";
-  const hh = String(d.getUTCHours()).padStart(2, "0");
-  const mm = String(d.getUTCMinutes()).padStart(2, "0");
-  return `${day}${hh}:${mm}`;
-}
-
-function formatPredDuration(s: number): string {
-  if (s >= 60) return `${Math.round(s / 60)} min`;
-  return `${s}s`;
-}
-
-function formatCountdown(ms: number): string {
-  const totalSec = Math.max(0, Math.floor(ms / 1000));
-  const m = Math.floor(totalSec / 60);
-  const s = totalSec % 60;
-  return `${m}:${String(s).padStart(2, "0")}`;
-}
-
-function elevationClass(deg: number): string {
-  if (deg >= 45) return "sat-pred-el-high";
-  if (deg >= 10) return "sat-pred-el-mid";
-  return "sat-pred-el-low";
-}
-
-// ── Predictions: countdown timer management ─────────────────────────
-function stopCountdownTimer() {
-  if (satPredCountdownTimer) {
-    clearInterval(satPredCountdownTimer);
-    satPredCountdownTimer = null;
-  }
-}
-
-function startCountdownTimer(container: HTMLElement | null): void {
-  const countdownEls = container?.querySelectorAll<HTMLElement>(".sat-pred-col-countdown") ?? [];
-  if (countdownEls.length === 0) return;
-
-  satPredCountdownTimer = setInterval(() => {
-    if (satActiveView !== "predictions") {
-      stopCountdownTimer();
-      return;
-    }
-    const n = Date.now();
-    let anyActive = false;
-    for (const el of countdownEls) {
-      const los = Number.parseInt(el.dataset.los ?? "0", 10);
-      const rem = los - n;
-      if (rem > 0) {
-        el.textContent = formatCountdown(rem);
-        anyActive = true;
-      } else {
-        el.textContent = "0:00";
-      }
-    }
-    if (!anyActive) {
-      stopCountdownTimer();
-      renderSatPredictions(getFilteredPredictions());
-    }
-  }, 1000);
-}
-
-// ── Predictions: row builders ───────────────────────────────────────
-function buildCurrentPassRow(pass: SatellitePass, now: number): HTMLElement {
-  const row = document.createElement("div");
-  row.className = "sat-pred-row-current";
-  const dir = `${azToCardinal(pass.azimuth_aos_deg)} \u2192 ${azToCardinal(pass.azimuth_los_deg)}`;
-  const remaining = Math.max(0, pass.los_ms - now);
-  row.innerHTML = [
-    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
-    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}\u00B0</span>`,
-    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
-    `<span class="sat-pred-col-time">${formatPredTime(pass.los_ms)}</span>`,
-    `<span class="sat-pred-col-countdown" data-los="${pass.los_ms}">${formatCountdown(remaining)}</span>`,
-    `<span class="sat-pred-col-dir">${dir}</span>`,
-  ].join("");
-  return row;
-}
-
-function buildUpcomingPassRow(pass: SatellitePass): HTMLElement {
-  const row = document.createElement("div");
-  row.className = "sat-pred-row";
-  const dir = `${azToCardinal(pass.azimuth_aos_deg)} \u2192 ${azToCardinal(pass.azimuth_los_deg)}`;
-  row.innerHTML = [
-    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
-    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
-    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}\u00B0</span>`,
-    `<span class="sat-pred-col-dur">${formatPredDuration(pass.duration_s)}</span>`,
-    `<span class="sat-pred-col-dir">${dir}</span>`,
-  ].join("");
-  return row;
-}
-
-// ── Predictions: filter state ───────────────────────────────────────
-function getFilteredPredictions(): SatellitePass[] {
-  let items = satPredData;
-  if (satPredCategory !== "all") items = items.filter((p) => p.category === satPredCategory);
-  if (satPredMinEl > 0) items = items.filter((p) => p.max_elevation_deg >= satPredMinEl);
-  if (satPredFilterText) items = items.filter((p) => p.satellite.toUpperCase().includes(satPredFilterText));
-  return items;
-}
-
-function applyPredFilters() {
-  renderSatPredictions(getFilteredPredictions());
-}
-
-const satPredictionFilter = satDom.predFilter;
-satPredictionFilter?.addEventListener("input", () => {
-  satPredFilterText = satPredictionFilter.value.trim().toUpperCase();
-  applyPredFilters();
-});
-
-const satPredictionMinElevation = satDom.predMinEl;
-satPredictionMinElevation?.addEventListener("change", () => {
-  satPredMinEl = Number.parseInt(satPredictionMinElevation.value, 10) || 0;
-  applyPredFilters();
-});
-
-const satPredictionCategory = satDom.predCategory;
-satPredictionCategory?.addEventListener("change", () => {
-  satPredCategory = satPredictionCategory.value;
-  applyPredFilters();
-});
-
-// ── Predictions: main render ────────────────────────────────────────
-function renderSatPredictions(passes: SatellitePass[], error?: string): void {
-  stopCountdownTimer();
-
-  if (error) {
-    if (satDom.predCurrentList)  satDom.predCurrentList.innerHTML = "";
-    if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-    if (satDom.predCurrentSec)   satDom.predCurrentSec.style.display = "none";
-    if (satDom.predUpcomingSec)  satDom.predUpcomingSec.style.display = "none";
-    if (satDom.predStatus)       satDom.predStatus.textContent = error;
-    return;
-  }
-
-  if (!Array.isArray(passes) || passes.length === 0) {
-    if (satDom.predCurrentList)  satDom.predCurrentList.innerHTML = "";
-    if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-    if (satDom.predCurrentSec)   satDom.predCurrentSec.style.display = "none";
-    if (satDom.predUpcomingSec)  satDom.predUpcomingSec.style.display = "none";
-    if (satDom.predStatus)       satDom.predStatus.textContent = "No passes found in the next 24 hours.";
-    return;
-  }
-
-  const now = Date.now();
-  const current = passes.filter((p) => p.aos_ms <= now && p.los_ms > now);
-  const upcoming = passes.filter((p) => p.aos_ms > now);
-
-  // ── Current passes ──
-  if (satDom.predCurrentSec) satDom.predCurrentSec.style.display = current.length > 0 ? "" : "none";
-  if (satDom.predCurrentList) {
-    if (current.length === 0) {
-      satDom.predCurrentList.innerHTML = "";
-    } else {
-      const frag = document.createDocumentFragment();
-      for (const pass of current) frag.appendChild(buildCurrentPassRow(pass, now));
-      satDom.predCurrentList.replaceChildren(frag);
-    }
-  }
-
-  // ── Upcoming passes ──
-  const upcomingLimit = satPredShowAll ? upcoming.length : SAT_PRED_PAGE_SIZE;
-  const visibleUpcoming = upcoming.slice(0, upcomingLimit);
-  const hiddenCount = upcoming.length - visibleUpcoming.length;
-  if (satDom.predUpcomingSec) satDom.predUpcomingSec.style.display = upcoming.length > 0 ? "" : "none";
-  if (satDom.predUpcomingList) {
-    const frag = document.createDocumentFragment();
-    for (const pass of visibleUpcoming) frag.appendChild(buildUpcomingPassRow(pass));
-    if (hiddenCount > 0) {
-      const moreRow = document.createElement("div");
-      moreRow.className = "sat-pred-row";
-      moreRow.style.cursor = "pointer";
-      moreRow.style.textAlign = "center";
-      moreRow.innerHTML = `<span style="grid-column:1/-1;color:var(--accent);font-size:0.82rem;">Show ${hiddenCount} more passes\u2026</span>`;
-      moreRow.addEventListener("click", () => {
-        satPredShowAll = true;
-        renderSatPredictions(getFilteredPredictions());
-      });
-      frag.appendChild(moreRow);
-    }
-    satDom.predUpcomingList.replaceChildren(frag);
-  }
-
-  // ── Status ──
-  if (satDom.predStatus) {
-    let text = `${current.length} active \u00B7 ${upcoming.length} upcoming \u00B7 times in UTC`;
-    if (satPredSatCount > 0) text += ` \u00B7 ${satPredSatCount} satellites tracked`;
-    satDom.predStatus.textContent = text;
-  }
-
-  // ── Countdown timer ──
-  if (current.length > 0 && satActiveView === "predictions") {
-    startCountdownTimer(satDom.predCurrentList);
-  }
-}
-
-// ── Predictions: data loading ───────────────────────────────────────
-async function loadSatPredictions(): Promise<void> {
-  if (satDom.predStatus)       satDom.predStatus.textContent = "Loading predictions\u2026";
-  if (satDom.predCurrentList)  satDom.predCurrentList.innerHTML = "";
-  if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-  try {
-    const resp = await fetch("/sat_passes");
-    if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
-    const data = await resp.json() as SatellitePassResponse;
-    satPredSatCount = data.satellite_count || 0;
-    if (data.error) {
-      satPredData = [];
-      renderSatPredictions([], data.error);
-    } else {
-      satPredData = data.passes || [];
-      renderSatPredictions(getFilteredPredictions());
-    }
-  } catch (error: unknown) {
-    renderSatPredictions([], `Failed to load predictions: ${error instanceof Error ? error.message : String(error)}`);
-  }
-}
-
 // ── Navigate to map centered on satellite image bounds ──────────────
 satWindow.satShowOnMap = function (south: number, west: number, north: number, east: number) {
   if (typeof satWindow.enableMapSourceFilter === "function") {

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugins/satellite-predictions.ts

@@ -0,0 +1,290 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+import type { SatellitePass, SatellitePassResponse } from "./satellite-types";
+
+// --- Satellite pass predictions ---
+//
+// Its own page rather than a third view inside the weather-satellite decoder:
+// when a bird comes over is a planning question, and it was buried under
+// Digital modes beside decoders it has nothing to do with.
+
+interface PredictionsBridge {
+  clearSatPredictionDom?: () => void;
+  refreshSatPredictions?: () => void;
+}
+const predWindow = window as unknown as PredictionsBridge;
+
+// ── DOM references (cached once) ───────────────────────────────────
+const dom = {
+  page:            document.getElementById("tab-satellites"),
+  filter:          document.getElementById("sat-pred-filter") as HTMLInputElement | null,
+  minElevation:    document.getElementById("sat-pred-min-el") as HTMLSelectElement | null,
+  category:        document.getElementById("sat-pred-category") as HTMLSelectElement | null,
+  currentList:     document.getElementById("sat-pred-current-list"),
+  upcomingList:    document.getElementById("sat-pred-list"),
+  currentSection:  document.getElementById("sat-pred-current-section"),
+  upcomingSection: document.getElementById("sat-pred-upcoming-section"),
+  status:          document.getElementById("sat-pred-status"),
+};
+
+// ── State ───────────────────────────────────────────────────────────
+const PAGE_SIZE = 50;
+let predShowAll = false;
+let predData: SatellitePass[] = [];
+let predFilterText = "";
+let predMinEl = 0;
+let predCategory = "all";
+let predSatCount = 0;
+let predCountdownTimer: ReturnType<typeof setInterval> | null = null;
+
+/** The countdowns tick once a second, so they stop when nobody is looking. */
+function isPageVisible(): boolean {
+  return !!dom.page && dom.page.style.display !== "none";
+}
+
+// ── Predictions: helpers ────────────────────────────────────────────
+function azToCardinal(deg: number): string {
+  const dirs = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
+  return dirs[Math.round(deg / 45) % 8] ?? "N";
+}
+
+function formatPredTime(ms: number): string {
+  const d = new Date(ms);
+  const now = new Date();
+  const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
+  const day = d.getUTCDay() !== now.getUTCDay() ? `${dayNames[d.getUTCDay()] ?? ""} ` : "";
+  const hh = String(d.getUTCHours()).padStart(2, "0");
+  const mm = String(d.getUTCMinutes()).padStart(2, "0");
+  return `${day}${hh}:${mm}`;
+}
+
+function formatPredDuration(s: number): string {
+  if (s >= 60) return `${Math.round(s / 60)} min`;
+  return `${s}s`;
+}
+
+function formatCountdown(ms: number): string {
+  const totalSec = Math.max(0, Math.floor(ms / 1000));
+  const m = Math.floor(totalSec / 60);
+  const s = totalSec % 60;
+  return `${m}:${String(s).padStart(2, "0")}`;
+}
+
+function elevationClass(deg: number): string {
+  if (deg >= 45) return "sat-pred-el-high";
+  if (deg >= 10) return "sat-pred-el-mid";
+  return "sat-pred-el-low";
+}
+
+// ── Predictions: countdown timer management ─────────────────────────
+function stopCountdownTimer() {
+  if (predCountdownTimer) {
+    clearInterval(predCountdownTimer);
+    predCountdownTimer = null;
+  }
+}
+
+function startCountdownTimer(container: HTMLElement | null): void {
+  const countdownEls = container?.querySelectorAll<HTMLElement>(".sat-pred-col-countdown") ?? [];
+  if (countdownEls.length === 0) return;
+
+  predCountdownTimer = setInterval(() => {
+    if (!isPageVisible()) {
+      stopCountdownTimer();
+      return;
+    }
+    const n = Date.now();
+    let anyActive = false;
+    for (const el of countdownEls) {
+      const los = Number.parseInt(el.dataset.los ?? "0", 10);
+      const rem = los - n;
+      if (rem > 0) {
+        el.textContent = formatCountdown(rem);
+        anyActive = true;
+      } else {
+        el.textContent = "0:00";
+      }
+    }
+    if (!anyActive) {
+      stopCountdownTimer();
+      render(filtered());
+    }
+  }, 1000);
+}
+
+// ── Predictions: row builders ───────────────────────────────────────
+function buildCurrentPassRow(pass: SatellitePass, now: number): HTMLElement {
+  const row = document.createElement("div");
+  row.className = "sat-pred-row-current";
+  const dir = `${azToCardinal(pass.azimuth_aos_deg)} \u2192 ${azToCardinal(pass.azimuth_los_deg)}`;
+  const remaining = Math.max(0, pass.los_ms - now);
+  row.innerHTML = [
+    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
+    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}\u00B0</span>`,
+    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
+    `<span class="sat-pred-col-time">${formatPredTime(pass.los_ms)}</span>`,
+    `<span class="sat-pred-col-countdown" data-los="${pass.los_ms}">${formatCountdown(remaining)}</span>`,
+    `<span class="sat-pred-col-dir">${dir}</span>`,
+  ].join("");
+  return row;
+}
+
+function buildUpcomingPassRow(pass: SatellitePass): HTMLElement {
+  const row = document.createElement("div");
+  row.className = "sat-pred-row";
+  const dir = `${azToCardinal(pass.azimuth_aos_deg)} \u2192 ${azToCardinal(pass.azimuth_los_deg)}`;
+  row.innerHTML = [
+    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
+    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
+    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}\u00B0</span>`,
+    `<span class="sat-pred-col-dur">${formatPredDuration(pass.duration_s)}</span>`,
+    `<span class="sat-pred-col-dir">${dir}</span>`,
+  ].join("");
+  return row;
+}
+
+// ── Predictions: filter state ───────────────────────────────────────
+function filtered(): SatellitePass[] {
+  let items = predData;
+  if (predCategory !== "all") items = items.filter((p) => p.category === predCategory);
+  if (predMinEl > 0) items = items.filter((p) => p.max_elevation_deg >= predMinEl);
+  if (predFilterText) items = items.filter((p) => p.satellite.toUpperCase().includes(predFilterText));
+  return items;
+}
+
+function applyFilters() {
+  render(filtered());
+}
+
+const filterInput = dom.filter;
+filterInput?.addEventListener("input", () => {
+  predFilterText = filterInput.value.trim().toUpperCase();
+  applyFilters();
+});
+
+const minElevationSelect = dom.minElevation;
+minElevationSelect?.addEventListener("change", () => {
+  predMinEl = Number.parseInt(minElevationSelect.value, 10) || 0;
+  applyFilters();
+});
+
+const categorySelect = dom.category;
+categorySelect?.addEventListener("change", () => {
+  predCategory = categorySelect.value;
+  applyFilters();
+});
+
+// ── Predictions: main render ────────────────────────────────────────
+function render(passes: SatellitePass[], error?: string): void {
+  stopCountdownTimer();
+
+  if (error) {
+    if (dom.currentList)  dom.currentList.innerHTML = "";
+    if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+    if (dom.currentSection)   dom.currentSection.style.display = "none";
+    if (dom.upcomingSection)  dom.upcomingSection.style.display = "none";
+    if (dom.status)       dom.status.textContent = error;
+    return;
+  }
+
+  if (!Array.isArray(passes) || passes.length === 0) {
+    if (dom.currentList)  dom.currentList.innerHTML = "";
+    if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+    if (dom.currentSection)   dom.currentSection.style.display = "none";
+    if (dom.upcomingSection)  dom.upcomingSection.style.display = "none";
+    if (dom.status)       dom.status.textContent = "No passes found in the next 24 hours.";
+    return;
+  }
+
+  const now = Date.now();
+  const current = passes.filter((p) => p.aos_ms <= now && p.los_ms > now);
+  const upcoming = passes.filter((p) => p.aos_ms > now);
+
+  // ── Current passes ──
+  if (dom.currentSection) dom.currentSection.style.display = current.length > 0 ? "" : "none";
+  if (dom.currentList) {
+    if (current.length === 0) {
+      dom.currentList.innerHTML = "";
+    } else {
+      const frag = document.createDocumentFragment();
+      for (const pass of current) frag.appendChild(buildCurrentPassRow(pass, now));
+      dom.currentList.replaceChildren(frag);
+    }
+  }
+
+  // ── Upcoming passes ──
+  const upcomingLimit = predShowAll ? upcoming.length : PAGE_SIZE;
+  const visibleUpcoming = upcoming.slice(0, upcomingLimit);
+  const hiddenCount = upcoming.length - visibleUpcoming.length;
+  if (dom.upcomingSection) dom.upcomingSection.style.display = upcoming.length > 0 ? "" : "none";
+  if (dom.upcomingList) {
+    const frag = document.createDocumentFragment();
+    for (const pass of visibleUpcoming) frag.appendChild(buildUpcomingPassRow(pass));
+    if (hiddenCount > 0) {
+      const moreRow = document.createElement("div");
+      moreRow.className = "sat-pred-row";
+      moreRow.style.cursor = "pointer";
+      moreRow.style.textAlign = "center";
+      moreRow.innerHTML = `<span style="grid-column:1/-1;color:var(--accent);font-size:0.82rem;">Show ${hiddenCount} more passes\u2026</span>`;
+      moreRow.addEventListener("click", () => {
+        predShowAll = true;
+        render(filtered());
+      });
+      frag.appendChild(moreRow);
+    }
+    dom.upcomingList.replaceChildren(frag);
+  }
+
+  // ── Status ──
+  if (dom.status) {
+    let text = `${current.length} active \u00B7 ${upcoming.length} upcoming \u00B7 times in UTC`;
+    if (predSatCount > 0) text += ` \u00B7 ${predSatCount} satellites tracked`;
+    dom.status.textContent = text;
+  }
+
+  // ── Countdown timer ──
+  if (current.length > 0 && isPageVisible()) {
+    startCountdownTimer(dom.currentList);
+  }
+}
+
+// ── Predictions: data loading ───────────────────────────────────────
+async function load(): Promise<void> {
+  if (dom.status)       dom.status.textContent = "Loading predictions\u2026";
+  if (dom.currentList)  dom.currentList.innerHTML = "";
+  if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+  try {
+    const resp = await fetch("/sat_passes");
+    if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
+    const data = await resp.json() as SatellitePassResponse;
+    predSatCount = data.satellite_count || 0;
+    if (data.error) {
+      predData = [];
+      render([], data.error);
+    } else {
+      predData = data.passes || [];
+      render(filtered());
+    }
+  } catch (error: unknown) {
+    render([], `Failed to load predictions: ${error instanceof Error ? error.message : String(error)}`);
+  }
+}
+
+// ── Page lifecycle ──────────────────────────────────────────────────
+function clearPredictionDom(): void {
+  stopCountdownTimer();
+  if (dom.currentList)  dom.currentList.innerHTML = "";
+  if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+}
+predWindow.clearSatPredictionDom = clearPredictionDom;
+
+/**
+ * Called by the router each time the Satellites page is opened, including the
+ * visit that imports this module — so loading is driven from one place only.
+ */
+predWindow.refreshSatPredictions = function () {
+  predShowAll = false;
+  void load();
+};

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugins/sstv.ts

@@ -0,0 +1,355 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// sstv.ts — SSTV decoder panel.
+//
+// Live view: decoder state, a canvas the picture fills row by row as it
+// arrives, and a card for the last one received. History view: a filterable
+// table of received pictures with thumbnails.
+//
+// Watching a picture build up is most of the appeal of the mode, so rows are
+// painted as they arrive rather than waiting for the frame to finish — a
+// transmission takes between 36 seconds and two minutes.
+
+import { hostCore } from "./host.js";
+
+import type { PluginRuntimeWindow } from "./runtime-contract.js";
+
+export {};
+
+interface SstvImage {
+  ts_ms?: number;
+  vis?: number;
+  mode?: string;
+  width?: number;
+  height?: number;
+  lines?: number;
+  complete?: boolean;
+  path?: string;
+  _tsMs?: number;
+  _ts?: string;
+}
+
+interface SstvProgress {
+  state?: string;
+  mode?: string;
+  width?: number;
+  height?: number;
+  line?: number;
+  line_data?: string;
+}
+
+interface SstvBridge {
+  getDecodeHistoryRetentionMs?: () => number;
+  trxScheduleUiFrameJob?: (key: string, job: () => void) => void;
+  takeSchedulerControlForDecoderDisable?: (button: HTMLElement) => Promise<unknown>;
+  syncSstvToggle?: (enabled: boolean) => void;
+}
+
+const sstvWindow = window as unknown as SstvBridge & PluginRuntimeWindow;
+
+const sstvDom = {
+  status: document.getElementById("sstv-status"),
+  liveView: document.getElementById("sstv-live-view"),
+  historyView: document.getElementById("sstv-history-view"),
+  liveContainer: document.getElementById("sstv-live-container"),
+  liveInfo: document.getElementById("sstv-live-info"),
+  liveCanvas: document.getElementById("sstv-live-canvas") as HTMLCanvasElement | null,
+  liveLatest: document.getElementById("sstv-live-latest"),
+  historyList: document.getElementById("sstv-history-list"),
+  historyCount: document.getElementById("sstv-history-count"),
+  filterInput: document.getElementById("sstv-filter") as HTMLInputElement | null,
+  sortSelect: document.getElementById("sstv-sort") as HTMLSelectElement | null,
+  toggleBtn: document.getElementById("sstv-decode-toggle-btn"),
+  clearBtn: document.getElementById("sstv-clear-btn"),
+  viewLiveBtn: document.getElementById("sstv-view-live"),
+  viewHistoryBtn: document.getElementById("sstv-view-history"),
+};
+
+const SSTV_MAX_IMAGES = 100;
+
+let sstvHistory: SstvImage[] = [];
+let liveCtx: CanvasRenderingContext2D | null = null;
+let liveMode = "";
+let liveHeight = 0;
+let liveRows = 0;
+let activeView: "live" | "history" = "live";
+let filterText = "";
+
+// ── Helpers ─────────────────────────────────────────────────────────
+
+function retentionMs(): number {
+  return sstvWindow.getDecodeHistoryRetentionMs?.() ?? 24 * 60 * 60 * 1000;
+}
+
+function pruneHistory() {
+  const cutoff = Date.now() - retentionMs();
+  sstvHistory = sstvHistory.filter((image) => (image._tsMs || 0) > cutoff);
+}
+
+function escapeHtml(value: unknown): string {
+  return String(value)
+    .replace(/&/g, "&amp;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/"/g, "&quot;");
+}
+
+function scheduleUi(key: string, job: () => void): void {
+  if (typeof sstvWindow.trxScheduleUiFrameJob === "function") {
+    sstvWindow.trxScheduleUiFrameJob(key, job);
+    return;
+  }
+  job();
+}
+
+/** The URL the server serves a saved picture from, given its stored path. */
+function imageUrl(image: SstvImage): string | null {
+  if (!image.path) return null;
+  const filename = image.path.split(/[\\/]/).pop();
+  return filename ? `/sstv-images/${encodeURIComponent(filename)}` : null;
+}
+
+function decodeBase64(data: string): Uint8Array {
+  const binary = atob(data);
+  const bytes = new Uint8Array(binary.length);
+  for (let i = 0; i < binary.length; i += 1) bytes[i] = binary.charCodeAt(i);
+  return bytes;
+}
+
+// ── View switching ──────────────────────────────────────────────────
+
+function switchView(view: "live" | "history"): void {
+  activeView = view;
+  if (sstvDom.liveView) sstvDom.liveView.style.display = view === "live" ? "" : "none";
+  if (sstvDom.historyView) sstvDom.historyView.style.display = view === "history" ? "" : "none";
+  for (const button of [sstvDom.viewLiveBtn, sstvDom.viewHistoryBtn]) {
+    button?.classList.remove("sat-view-active");
+  }
+  if (view === "live") sstvDom.viewLiveBtn?.classList.add("sat-view-active");
+  else sstvDom.viewHistoryBtn?.classList.add("sat-view-active");
+  if (view === "history") renderHistoryTable();
+}
+
+sstvDom.viewLiveBtn?.addEventListener("click", () => { switchView("live"); });
+sstvDom.viewHistoryBtn?.addEventListener("click", () => { switchView("history"); });
+
+// ── Live canvas ─────────────────────────────────────────────────────
+
+/** Start a new picture: size the canvas to the mode and clear it. */
+function beginPicture(mode: string, width: number, height: number): void {
+  const canvas = sstvDom.liveCanvas;
+  if (!canvas || width <= 0 || height <= 0) return;
+  liveMode = mode;
+  liveHeight = height;
+  liveRows = 0;
+  canvas.width = width;
+  canvas.height = height;
+  liveCtx = canvas.getContext("2d");
+  if (!liveCtx) return;
+  // Mid-grey, not black: the rows below the one arriving have not been
+  // received, which is a different thing from having been received as black.
+  liveCtx.fillStyle = "#606060";
+  liveCtx.fillRect(0, 0, width, height);
+  if (sstvDom.liveContainer) sstvDom.liveContainer.style.display = "";
+  updateLiveInfo();
+}
+
+function updateLiveInfo(): void {
+  if (!sstvDom.liveInfo) return;
+  const canvas = sstvDom.liveCanvas;
+  const size = canvas ? `${canvas.width}×${canvas.height}` : "";
+  sstvDom.liveInfo.textContent = liveMode
+    ? `${liveMode} · ${size} · line ${liveRows}${liveHeight ? ` of ${liveHeight}` : ""}`
+    : "";
+}
+
+/** Paint one row of RGB triples at its own line number. */
+function paintRow(line: number, rgb: Uint8Array): void {
+  const canvas = sstvDom.liveCanvas;
+  if (!liveCtx || !canvas) return;
+  const width = canvas.width;
+  if (line < 0 || line >= canvas.height || rgb.length < width * 3) return;
+  const row = liveCtx.createImageData(width, 1);
+  for (let x = 0; x < width; x += 1) {
+    row.data[x * 4] = rgb[x * 3] ?? 0;
+    row.data[x * 4 + 1] = rgb[x * 3 + 1] ?? 0;
+    row.data[x * 4 + 2] = rgb[x * 3 + 2] ?? 0;
+    row.data[x * 4 + 3] = 255;
+  }
+  liveCtx.putImageData(row, 0, line);
+  liveRows = Math.max(liveRows, line + 1);
+}
+
+// ── Server messages ─────────────────────────────────────────────────
+
+function onProgress(msg: SstvProgress): void {
+  if (msg.state) {
+    if (sstvDom.status) sstvDom.status.textContent = msg.state;
+    // A state update carries the geometry; a row update carries only the row.
+    beginPicture(msg.mode || "", msg.width || 0, msg.height || 0);
+    return;
+  }
+  if (typeof msg.line !== "number" || !msg.line_data) return;
+  const line = msg.line;
+  const rgb = decodeBase64(msg.line_data);
+  scheduleUi(`sstv-row-${line}`, () => {
+    paintRow(line, rgb);
+    updateLiveInfo();
+  });
+}
+
+function onImage(msg: SstvImage): void {
+  const image: SstvImage = { ...msg };
+  image._tsMs = typeof msg.ts_ms === "number" ? msg.ts_ms : Date.now();
+  image._ts = new Date(image._tsMs).toLocaleTimeString();
+  sstvHistory.push(image);
+  if (sstvHistory.length > SSTV_MAX_IMAGES) sstvHistory.shift();
+  pruneHistory();
+
+  if (sstvDom.status) {
+    sstvDom.status.textContent = image.complete
+      ? `Received ${image.mode ?? "picture"}`
+      : `Partial ${image.mode ?? "picture"} — ${image.lines ?? 0} lines`;
+  }
+  scheduleUi("sstv-latest", renderLatestCard);
+  if (activeView === "history") scheduleUi("sstv-history", renderHistoryTable);
+}
+
+// ── Rendering ───────────────────────────────────────────────────────
+
+function renderLatestCard(): void {
+  if (!sstvDom.liveLatest) return;
+  const latest = sstvHistory[sstvHistory.length - 1];
+  if (!latest) {
+    sstvDom.liveLatest.innerHTML = "";
+    return;
+  }
+  const url = imageUrl(latest);
+  const lines = `${latest.lines ?? 0}${latest.height ? ` of ${latest.height}` : ""} lines`;
+  const state = latest.complete ? "complete" : "partial";
+  sstvDom.liveLatest.innerHTML = `
+    <div class="sat-latest-card">
+      <div style="display:flex; align-items:baseline; gap:0.5rem; flex-wrap:wrap;">
+        <strong>${escapeHtml(latest.mode ?? "SSTV")}</strong>
+        <small style="color:var(--text-muted);">${escapeHtml(latest._ts ?? "")} · ${lines} · ${state}</small>
+      </div>
+      ${url
+        ? `<a href="${escapeHtml(url)}" target="_blank" rel="noopener">
+             <img src="${escapeHtml(url)}" alt="Received ${escapeHtml(latest.mode ?? "SSTV")} picture"
+                  style="margin-top:0.4rem; width:100%; max-width:640px; image-rendering:pixelated;" />
+           </a>`
+        : ""}
+    </div>`;
+}
+
+function filteredHistory(): SstvImage[] {
+  const text = filterText.trim().toLowerCase();
+  const matching = text
+    ? sstvHistory.filter((image) => (image.mode ?? "").toLowerCase().includes(text))
+    : sstvHistory.slice();
+  const newestFirst = (sstvDom.sortSelect?.value ?? "newest") === "newest";
+  matching.sort((a, b) => (newestFirst ? 1 : -1) * ((b._tsMs ?? 0) - (a._tsMs ?? 0)));
+  return matching;
+}
+
+function renderHistoryTable(): void {
+  if (!sstvDom.historyList) return;
+  pruneHistory();
+  const rows = filteredHistory();
+  sstvDom.historyList.innerHTML = rows
+    .map((image) => {
+      const url = imageUrl(image);
+      const size = image.width && image.height ? `${image.width}×${image.height}` : "--";
+      const lines = image.complete
+        ? String(image.lines ?? 0)
+        : `${image.lines ?? 0} (partial)`;
+      return `<div class="sat-history-row">
+        <span class="sat-col-time">${escapeHtml(image._ts ?? "")}</span>
+        <span class="sat-col-type">${escapeHtml(image.mode ?? "--")}</span>
+        <span class="sat-col-sat">${escapeHtml(size)}</span>
+        <span class="sat-col-lines">${escapeHtml(lines)}</span>
+        <span class="sat-col-link">${url
+          ? `<a href="${escapeHtml(url)}" target="_blank" rel="noopener">View</a>`
+          : "--"}</span>
+      </div>`;
+    })
+    .join("");
+  if (sstvDom.historyCount) {
+    sstvDom.historyCount.textContent = rows.length
+      ? `${rows.length} picture${rows.length === 1 ? "" : "s"}`
+      : "No pictures yet";
+  }
+}
+
+sstvDom.filterInput?.addEventListener("input", () => {
+  filterText = sstvDom.filterInput?.value ?? "";
+  renderHistoryTable();
+});
+sstvDom.sortSelect?.addEventListener("change", () => { renderHistoryTable(); });
+
+// ── Decoder history plumbing ────────────────────────────────────────
+
+function restoreHistory(entries: unknown[]): void {
+  if (!Array.isArray(entries)) return;
+  for (const entry of entries) onImage(entry as SstvImage);
+}
+
+function resetHistoryView(): void {
+  sstvHistory = [];
+  liveRows = 0;
+  liveMode = "";
+  if (sstvDom.liveContainer) sstvDom.liveContainer.style.display = "none";
+  if (sstvDom.status) sstvDom.status.textContent = "Idle";
+  renderLatestCard();
+  renderHistoryTable();
+}
+
+// ── Controls ────────────────────────────────────────────────────────
+
+sstvWindow.syncSstvToggle = function syncSstvToggle(enabled: boolean) {
+  const button = sstvDom.toggleBtn as HTMLButtonElement | null;
+  if (!button) return;
+  button.textContent = enabled ? "Disable SSTV" : "Enable SSTV";
+  button.setAttribute("aria-pressed", String(enabled));
+  button.classList.toggle("is-active", enabled);
+};
+
+sstvDom.toggleBtn?.addEventListener("click", () => {
+  void (async () => {
+    try {
+      if (sstvDom.toggleBtn) {
+        await sstvWindow.takeSchedulerControlForDecoderDisable?.(sstvDom.toggleBtn);
+      }
+      await hostCore.postPath("/toggle_sstv_decode");
+    } catch (e) {
+      console.error("SSTV toggle failed", e);
+    }
+  })();
+});
+
+sstvDom.clearBtn?.addEventListener("click", () => {
+  void (async () => {
+    try {
+      await hostCore.postPath("/clear_sstv_decode");
+      resetHistoryView();
+    } catch (e) {
+      console.error("SSTV clear failed", e);
+    }
+  })();
+});
+
+renderLatestCard();
+
+sstvWindow.trxPluginRuntime.registerDecoder({
+  id: "sstv",
+  onMessage: onImage as (msg: unknown) => void,
+  restore: restoreHistory,
+  prune: renderHistoryTable,
+  reset: resetHistoryView,
+});
+sstvWindow.trxPluginRuntime.registerDecoder({
+  id: "sstv_progress",
+  onMessage: onProgress as (msg: unknown) => void,
+});

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/ui-core.ts

@@ -499,7 +499,7 @@ function elementById<T extends HTMLElement>(id: string): T {
       if (restoreFocus) more.focus();
     };
     api.closeMobileOverlays = closeMore;
-    ["statistics", "recorder", "settings", "about"].forEach((tabName) => {
+    ["satellites", "statistics", "recorder", "settings", "about"].forEach((tabName) => {
       const source = nav.querySelector(`[data-tab="${tabName}"]`);
       if (!source) return;
       const item = document.createElement("button");
@@ -541,7 +541,7 @@ function elementById<T extends HTMLElement>(id: string): T {
     select.setAttribute("aria-label", "Decoder view");
     const groups: Array<[string, string[]]> = [
       ["Overview", ["overview"]], ["Marine & packet", ["ais", "vdes", "aprs", "hf-aprs"]],
-      ["Weak signal", ["cw", "ft8", "ft4", "ft2", "wspr"]], ["Broadcast & images", ["rds", "sat", "wefax"]],
+      ["Weak signal", ["cw", "ft8", "ft4", "ft2", "wspr"]], ["Broadcast & images", ["rds", "sat", "wefax", "sstv"]],
     ];
     groups.forEach(([label, ids]) => {
       const group = document.createElement("optgroup");

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/mobile-layout.mjs

@@ -0,0 +1,149 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// What a phone gets. A page that scrolls sideways is a page with something on
+// it nobody will find: the transmit controls spent this whole period laid out
+// at x=400 on a 390 px screen, off the side of a tray 354 px wide, reachable
+// only by a horizontal scroll with nothing to say it was there.
+
+import assert from "node:assert/strict";
+import { chromium } from "playwright-core";
+import { startBrowser, startWebFixture } from "./web-fixture.mjs";
+
+/* global document, getComputedStyle */
+
+const PHONES = [430, 390, 360];
+
+const fixture = await startWebFixture({ spectrum: true, tx: true });
+const { browser, page, runtimeErrors } = await startBrowser(chromium);
+
+try {
+  for (const width of PHONES) {
+    await page.setViewportSize({ width, height: 900 });
+    await page.goto(fixture.origin, { waitUntil: "domcontentloaded" });
+    await page.locator("#content").waitFor({ state: "visible" });
+    await page.waitForTimeout(1800);
+
+    const layout = await page.evaluate((viewport) => {
+      const box = (element) => element.getBoundingClientRect();
+      // Anything laid out past the right edge of the screen.
+      const past = [];
+      const walk = (element) => {
+        const rect = box(element);
+        if (rect.width > 0 && rect.right > viewport + 1) {
+          past.push(`${element.tagName.toLowerCase()}${element.id ? `#${element.id}` : ""}`);
+        }
+        for (const child of element.children) walk(child);
+      };
+      walk(document.getElementById("content"));
+      const tx = document.getElementById("tx-power-col");
+      return {
+        documentScroll: document.documentElement.scrollWidth,
+        past: past.slice(0, 6),
+        txRight: tx ? Math.round(box(tx).right) : null,
+        txVisible: tx ? getComputedStyle(tx).display !== "none" : false,
+        rigSelect: Math.round(box(document.getElementById("header-rig-switch-select")).width),
+      };
+    }, width);
+
+    assert.equal(layout.documentScroll, width,
+      `the page scrolls sideways at ${width}px (${layout.documentScroll}px wide)`);
+    assert.deepEqual(layout.past, [],
+      `laid out past the screen at ${width}px: ${layout.past.join(", ")}`);
+    if (layout.txVisible) {
+      assert.ok(layout.txRight <= width + 1,
+        `the transmit controls end at ${layout.txRight}px on a ${width}px screen`);
+    }
+    // The rig's name was taking 139px of a 338px bar and pushing everything
+    // else into the overflow menu.
+    assert.ok(layout.rigSelect <= 112,
+      `the rig picker is ${layout.rigSelect}px wide at ${width}px`);
+
+    // The bottom nav keeps its labels — that is what makes it navigation
+    // rather than five glyphs — and a label used to overflow its tab and run
+    // into the next one: "Bookmarks igital mode".
+    //
+    // What is asserted is that a label stays inside its own tab and, if it is
+    // too long for it, ends in an ellipsis. Not that it fits: how wide a
+    // platform draws a word varies by more than ten per cent, so "it fits"
+    // passes on the machine it was written on and fails on the next one —
+    // which is what a fixed font size did here.
+    const nav = await page.evaluate(() => {
+      const bar = document.querySelector(".tab-bar-nav");
+      return [...bar.querySelectorAll(".tab")]
+        .filter((tab) => tab.getBoundingClientRect().width > 0)
+        .map((tab) => {
+          const label = [...tab.querySelectorAll(".tab-label, .tab-label-short")]
+            .find((span) => getComputedStyle(span).display !== "none");
+          const style = label ? getComputedStyle(label) : null;
+          const labelBox = label?.getBoundingClientRect();
+          const tabBox = tab.getBoundingClientRect();
+          return {
+            text: (label?.textContent ?? "").trim(),
+            escapes: labelBox
+              ? labelBox.left < tabBox.left - 1 || labelBox.right > tabBox.right + 1
+              : false,
+            truncates: style?.textOverflow === "ellipsis" && style?.overflow !== "visible",
+            empty: !labelBox || labelBox.width < 1,
+          };
+        });
+    });
+    assert.ok(nav.length >= 4, `the bottom nav has ${nav.length} destinations at ${width}px`);
+    const escaped = nav.filter((tab) => tab.escapes).map((tab) => tab.text);
+    assert.deepEqual(escaped, [],
+      `labels overflowing their tab at ${width}px: ${escaped.join(", ")}`);
+    const untruncatable = nav.filter((tab) => !tab.truncates).map((tab) => tab.text);
+    assert.deepEqual(untruncatable, [],
+      `labels that would be cut rather than ellipsised at ${width}px: ${untruncatable.join(", ")}`);
+    const blank = nav.filter((tab) => tab.empty).map((tab, index) => tab.text || `#${index}`);
+    assert.deepEqual(blank, [], `destinations with no label at ${width}px: ${blank.join(", ")}`);
+  }
+
+  // A tab whose visible label is shortened for the nav still has to say what
+  // it is to anything that reads the page rather than looks at it.
+  const named = await page.evaluate(() => {
+    const tab = document.querySelector('.tab[data-tab="digital-modes"]');
+    const short = tab.querySelector(".tab-label-short");
+    return {
+      label: tab.getAttribute("aria-label"),
+      shortHidden: short?.getAttribute("aria-hidden"),
+    };
+  });
+  assert.equal(named.label, "Digital modes", "the shortened tab lost its full name");
+  assert.equal(named.shortHidden, "true", "the short label is read out as well as shown");
+
+  // Hiding the map's filters leaves the bar, and the bar has to still be
+  // there to bring them back — it carries the only button that does.
+  await page.setViewportSize({ width: 1400, height: 900 });
+  await page.goto(`${fixture.origin}/map`, { waitUntil: "domcontentloaded" });
+  await page.locator("#aprs-map .leaflet-pane").first().waitFor({ state: "attached" });
+  await page.waitForTimeout(1200);
+  await page.locator("#map-overlay-toggle-btn").click();
+  await page.waitForTimeout(400);
+  const collapsed = await page.evaluate(() => {
+    const panel = document.querySelector(".map-overlay-panel");
+    const style = getComputedStyle(panel);
+    const rect = panel.getBoundingClientRect();
+    const button = document.getElementById("map-overlay-toggle-btn").getBoundingClientRect();
+    return {
+      width: Math.round(rect.width),
+      height: Math.round(rect.height),
+      opacity: Number(style.opacity),
+      visibility: style.visibility,
+      display: style.display,
+      buttonWidth: Math.round(button.width),
+    };
+  });
+  assert.ok(collapsed.width > 0 && collapsed.height > 0,
+    `the collapsed bar measures ${collapsed.width}x${collapsed.height}`);
+  assert.equal(collapsed.visibility, "visible", "the collapsed bar is not visible");
+  assert.notEqual(collapsed.display, "none", "the collapsed bar is display:none");
+  assert.equal(collapsed.opacity, 1, `the collapsed bar is at opacity ${collapsed.opacity}`);
+  assert.ok(collapsed.buttonWidth > 0, "Show Filters has no size to click");
+
+  assert.deepEqual(runtimeErrors, []);
+} finally {
+  await browser.close();
+  await fixture.close();
+}

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/satellite-predictions.mjs

@@ -0,0 +1,122 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// Pass predictions used to be a third view inside the weather-satellite
+// decoder, under Digital modes — a planning tool filed with the decoders it has
+// nothing to do with. It is its own page now, so what this guards is that the
+// page exists at its own address, renders passes, and that the decoder card no
+// longer offers the view it gave up.
+
+import assert from "node:assert/strict";
+import { chromium } from "playwright-core";
+import { startBrowser, startWebFixture } from "./web-fixture.mjs";
+
+/* global document, window, getComputedStyle */
+
+const HOUR = 3_600_000;
+const now = Date.now();
+const satPasses = {
+  satellite_count: 2,
+  passes: [
+    // In progress right now, so the page has a countdown to run.
+    {
+      satellite: "NOAA 19", category: "weather",
+      aos_ms: now - 4 * 60_000, los_ms: now + 6 * 60_000,
+      max_elevation_deg: 62.4, duration_s: 600,
+      azimuth_aos_deg: 10, azimuth_los_deg: 190,
+    },
+    {
+      satellite: "ISS", category: "amateur",
+      aos_ms: now + 2 * HOUR, los_ms: now + 2 * HOUR + 480_000,
+      max_elevation_deg: 18.2, duration_s: 480,
+      azimuth_aos_deg: 200, azimuth_los_deg: 20,
+    },
+  ],
+};
+
+const fixture = await startWebFixture({ satPasses });
+const { browser, page, runtimeErrors } = await startBrowser(chromium);
+
+try {
+  await page.setViewportSize({ width: 1500, height: 950 });
+
+  // The page is reachable at its own address, not through a decoder sub-view.
+  // #content is the radio panel on the main tab, so the readiness signal for a
+  // deep link is the destination panel itself.
+  await page.goto(`${fixture.origin}/satellites`, { waitUntil: "domcontentloaded" });
+  await page.locator("#tab-satellites").waitFor({ state: "visible" });
+
+  await page.waitForFunction(
+    () => (document.getElementById("sat-pred-list")?.childElementCount ?? 0) > 0,
+    null,
+    { timeout: 5000 },
+  );
+
+  const rendered = await page.evaluate(() => ({
+    current: document.getElementById("sat-pred-current-list").textContent,
+    upcoming: document.getElementById("sat-pred-list").textContent,
+    status: document.getElementById("sat-pred-status").textContent,
+    activeTab: document.querySelector(".tab-bar .tab.active")?.dataset.tab,
+  }));
+  assert.match(rendered.current, /NOAA 19/, `current passes read "${rendered.current}"`);
+  assert.match(rendered.upcoming, /ISS/, `upcoming passes read "${rendered.upcoming}"`);
+  assert.match(rendered.status, /1 active/, `status reads "${rendered.status}"`);
+  assert.equal(rendered.activeTab, "satellites", "the Satellites tab is the active one");
+
+  // A pass in progress counts down, so the seconds have to move on their own.
+  const firstTick = await page.evaluate(
+    () => document.querySelector(".sat-pred-col-countdown[data-los]")?.textContent);
+  await page.waitForTimeout(1600);
+  const secondTick = await page.evaluate(
+    () => document.querySelector(".sat-pred-col-countdown[data-los]")?.textContent);
+  assert.notEqual(firstTick, secondTick, `the countdown sat at ${firstTick}`);
+
+  // Leaving stops the countdown rather than leaving a timer running behind a
+  // hidden page.
+  await page.evaluate(() => { window.navigateToTab("main"); });
+  await page.waitForTimeout(300);
+  const afterLeaving = await page.evaluate(() => ({
+    visible: document.getElementById("tab-satellites").style.display,
+    rows: document.getElementById("sat-pred-current-list").childElementCount,
+  }));
+  assert.equal(afterLeaving.visible, "none", "the page stayed on screen after navigating away");
+  assert.equal(afterLeaving.rows, 0, "the countdown rows outlived the page");
+
+  // Coming back reloads rather than showing whatever was there before.
+  await page.evaluate(() => { window.navigateToTab("satellites"); });
+  await page.waitForFunction(
+    () => (document.getElementById("sat-pred-list")?.childElementCount ?? 0) > 0,
+    null,
+    { timeout: 5000 },
+  );
+
+  // The page is an occasional destination, so it lives behind Tools rather than
+  // taking a slot in the operating strip — the same treatment Statistics,
+  // Recorder, Settings and About get.
+  const nav = await page.evaluate(() => ({
+    inStrip: getComputedStyle(document.querySelector('.tab-bar-nav .tab[data-tab="satellites"]')).display,
+    inTools: !!document.querySelector('#mobile-more-menu [data-navigate-tab="satellites"]'),
+  }));
+  assert.equal(nav.inStrip, "none", "Satellites took a slot in the operating strip");
+  assert.ok(nav.inTools, "Satellites is not reachable from Tools");
+
+  // The decoder card keeps Live and History, and no longer offers Predictions.
+  await page.goto(`${fixture.origin}/digital-modes`, { waitUntil: "domcontentloaded" });
+  await page.locator("#tab-digital-modes").waitFor({ state: "visible" });
+  const satCard = await page.evaluate(() => ({
+    predictionsButton: !!document.getElementById("sat-view-predictions"),
+    predictionsView: !!document.getElementById("sat-predictions-view"),
+    live: !!document.getElementById("sat-view-live"),
+    history: !!document.getElementById("sat-view-history"),
+  }));
+  assert.equal(satCard.predictionsButton, false, "the decoder card still offers Predictions");
+  assert.equal(satCard.predictionsView, false, "the old predictions view is still in the page");
+  assert.ok(satCard.live && satCard.history, "the decoder card lost Live/History");
+
+  assert.deepEqual(runtimeErrors, [], "the page threw while showing predictions");
+  console.log("satellite predictions page tests passed");
+} finally {
+  await browser.close();
+  await fixture.close();
+}

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/spectrum-layout.mjs

@@ -196,6 +196,62 @@ try {
   await fixture.close();
 }
 
+// The strip of controls under the plot. Its two clusters — the receiver's
+// bandwidth and the display's levels — used to size themselves independently:
+// four control heights on one line, and between about 1100 and 1400 px the
+// left cluster wrapped to two lines while the right one did not, leaving the
+// two at heights that matched neither each other nor anything else.
+const stripFixture = await startWebFixture({ spectrum: true });
+const strip = await startBrowser(chromium);
+try {
+  for (const width of [1600, 1200, 900]) {
+    await strip.page.setViewportSize({ width, height: 950 });
+    await strip.page.goto(stripFixture.origin, { waitUntil: "domcontentloaded" });
+    await strip.page.locator("#spectrum-panel").waitFor({ state: "visible" });
+    await strip.page.waitForTimeout(1600);
+
+    const measured = await strip.page.evaluate(() => {
+      const controls = document.getElementById("spectrum-controls");
+      const box = (element) => element.getBoundingClientRect();
+      const clusters = [...controls.children]
+        .filter((child) => child.id)
+        .map((child) => ({ id: child.id, top: Math.round(box(child).top) }));
+      const parts = [...controls.querySelectorAll(".spectrum-field, .spectrum-btn")];
+      return {
+        heights: [...new Set(parts.map((part) => Math.round(box(part).height)))],
+        count: parts.length,
+        clusters,
+        // Rows are lines of the strip: clusters sharing a top are on one line.
+        lines: new Set(clusters.map((cluster) => cluster.top)).size,
+        overflows: controls.scrollWidth > controls.clientWidth + 1,
+        insidePanel: box(controls).right
+          <= box(document.getElementById("spectrum-panel")).right + 1,
+      };
+    });
+
+    // Five fields and four buttons: bandwidth, Set, Auto BW, Sweet-spot, peak
+    // hold, floor, range, Auto, contrast.
+    assert.equal(measured.count, 9, `the strip has ${measured.count} controls at ${width}px`);
+    assert.deepEqual(measured.heights.length, 1,
+      `controls are ${measured.heights.join(", ")}px tall at ${width}px`);
+    assert.equal(measured.overflows, false, `the strip overflows at ${width}px`);
+    assert.equal(measured.insidePanel, true, `the strip runs past the plot at ${width}px`);
+
+    // Either both clusters share a line, or each has one to itself. What must
+    // never happen is one cluster floating against the middle of the other.
+    const tops = measured.clusters.map((cluster) => cluster.top);
+    assert.ok(
+      measured.lines === 1 || measured.lines === measured.clusters.length,
+      `clusters sit at ${tops.join(", ")} at ${width}px`,
+    );
+  }
+
+  assert.deepEqual(strip.runtimeErrors, []);
+} finally {
+  await strip.browser.close();
+  await stripFixture.close();
+}
+
 // The band plan is fetched once at startup, which can land before the session
 // exists. It used to fail silently and never retry, so the allocations only
 // turned up if the operator reloaded the page by hand.

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/sstv.test.mjs

@@ -0,0 +1,186 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// The SSTV panel: a picture arriving row by row, and what is kept once it has.
+// Watching the image build up is the point of the mode, so rows have to reach
+// the canvas as they arrive rather than at the end of a two-minute frame.
+
+import assert from "node:assert/strict";
+import test from "node:test";
+import vm from "node:vm";
+import { bundleEntry } from "./bundle-entry.mjs";
+import { createHost } from "./host-fixture.mjs";
+
+/** A DOM stub with only what the plugin reaches for. */
+function makeElement(id) {
+  const listeners = new Map();
+  return {
+    id,
+    textContent: "",
+    innerHTML: "",
+    value: "",
+    style: {},
+    attributes: {},
+    classList: {
+      classes: new Set(),
+      add(name) { this.classes.add(name); },
+      remove(name) { this.classes.delete(name); },
+      toggle(name, on) { if (on) this.classes.add(name); else this.classes.delete(name); },
+      contains(name) { return this.classes.has(name); },
+    },
+    addEventListener(type, handler) { listeners.set(type, handler); },
+    setAttribute(name, value) { this.attributes[name] = String(value); },
+    getAttribute(name) { return this.attributes[name] ?? null; },
+    click() { listeners.get("click")?.(); },
+    fire(type, event) { listeners.get(type)?.(event); },
+  };
+}
+
+function makeCanvas(id) {
+  const element = makeElement(id);
+  element.width = 0;
+  element.height = 0;
+  const painted = [];
+  const fills = [];
+  element.painted = painted;
+  element.fills = fills;
+  element.getContext = () => ({
+    fillStyle: "",
+    fillRect: (...args) => { fills.push(args); },
+    createImageData: (width, height) => ({
+      width, height, data: new Uint8ClampedArray(width * height * 4),
+    }),
+    putImageData: (image, x, y) => { painted.push({ x, y, data: image.data }); },
+  });
+  return element;
+}
+
+async function loadPanel() {
+  const elements = new Map();
+  const element = (id) => {
+    if (!elements.has(id)) {
+      elements.set(id, id.endsWith("canvas") ? makeCanvas(id) : makeElement(id));
+    }
+    return elements.get(id);
+  };
+  // Touch every id the panel defines, so the plugin caches real stubs.
+  for (const id of [
+    "sstv-status", "sstv-live-view", "sstv-history-view", "sstv-live-container",
+    "sstv-live-info", "sstv-live-canvas", "sstv-live-latest", "sstv-history-list",
+    "sstv-history-count", "sstv-filter", "sstv-sort", "sstv-decode-toggle-btn",
+    "sstv-clear-btn", "sstv-view-live", "sstv-view-history",
+  ]) element(id);
+
+  const window = { ...createHost() };
+  const context = vm.createContext({
+    window,
+    document: { getElementById: (id) => elements.get(id) ?? null },
+    atob: (data) => Buffer.from(data, "base64").toString("binary"),
+    Date, Number, String, Math, Set, Uint8Array, Uint8ClampedArray, JSON, console,
+  });
+  const runtime = await bundleEntry(new URL("../src/plugin-runtime.ts", import.meta.url));
+  const source = await bundleEntry(new URL("../src/plugins/sstv.ts", import.meta.url));
+  new vm.Script(runtime).runInContext(context);
+  new vm.Script(source).runInContext(context);
+  return { window, runtime: window.trxPluginRuntime, element };
+}
+
+/** One row of RGB triples, base64 as the server sends it. */
+function rowData(width, [r, g, b]) {
+  const bytes = new Uint8Array(width * 3);
+  for (let x = 0; x < width; x += 1) {
+    bytes[x * 3] = r;
+    bytes[x * 3 + 1] = g;
+    bytes[x * 3 + 2] = b;
+  }
+  return Buffer.from(bytes).toString("base64");
+}
+
+test("a picture arriving paints its rows as they come", async () => {
+  const { runtime, element } = await loadPanel();
+
+  // The header names the mode and the geometry; the canvas takes both.
+  runtime.dispatch("sstv_progress", {
+    state: "Receiving Martin M1", mode: "Martin M1", width: 320, height: 256, line: 0,
+  });
+  const canvas = element("sstv-live-canvas");
+  assert.equal(canvas.width, 320, "the canvas did not take the mode's width");
+  assert.equal(canvas.height, 256, "the canvas did not take the mode's height");
+  assert.equal(element("sstv-live-container").style.display, "",
+    "the live view stayed hidden while a picture was arriving");
+  assert.match(element("sstv-status").textContent, /Martin M1/);
+
+  // Rows land at the line number they carry, not in arrival order: a decoder
+  // that painted them in sequence would shear a picture with a dropped line.
+  runtime.dispatch("sstv_progress", { line: 4, line_data: rowData(320, [255, 0, 0]) });
+  runtime.dispatch("sstv_progress", { line: 2, line_data: rowData(320, [0, 0, 255]) });
+  assert.deepEqual(canvas.painted.map((p) => p.y), [4, 2],
+    `rows painted at ${canvas.painted.map((p) => p.y).join(",")}`);
+  assert.deepEqual([...canvas.painted[0].data.slice(0, 4)], [255, 0, 0, 255], "row 4 is not red");
+  assert.deepEqual([...canvas.painted[1].data.slice(0, 4)], [0, 0, 255, 255], "row 2 is not blue");
+  assert.match(element("sstv-live-info").textContent, /Martin M1/);
+});
+
+test("a received picture is kept, shown, and linked by file name alone", async () => {
+  const { runtime, element } = await loadPanel();
+
+  // Recent, not a fixed date: the panel drops anything older than the history
+  // retention window, so a picture stamped with the day the test was written
+  // passes until that day is a day ago.
+  runtime.dispatch("sstv", {
+    ts_ms: Date.now() - 60_000,
+    vis: 44, mode: "Martin M1", width: 320, height: 256, lines: 256, complete: true,
+    path: "/home/op/.cache/trx-rs/sstv/SSTV_20260805T120000Z_14230000_Martin-M1.png",
+  });
+
+  const latest = element("sstv-live-latest").innerHTML;
+  assert.match(latest, /Martin M1/);
+  assert.match(latest, /complete/);
+  // The server serves pictures by file name; the path it stored is its own.
+  assert.match(latest, /\/sstv-images\/SSTV_20260805T120000Z_14230000_Martin-M1\.png/);
+  assert.doesNotMatch(latest, /home\/op/, "the server's filesystem path reached the page");
+
+  element("sstv-view-history").click();
+  const history = element("sstv-history-list").innerHTML;
+  assert.match(history, /Martin M1/);
+  assert.match(history, /320×256/);
+  assert.match(element("sstv-history-count").textContent, /1 picture/);
+});
+
+test("a picture cut short is kept, and says so", async () => {
+  const { runtime, element } = await loadPanel();
+
+  runtime.dispatch("sstv", {
+    ts_ms: Date.now(), vis: 60, mode: "Scottie S1", width: 320, height: 256,
+    lines: 91, complete: false, path: "/cache/SSTV_x_Scottie-S1.png",
+  });
+
+  assert.match(element("sstv-status").textContent, /Partial/);
+  element("sstv-view-history").click();
+  assert.match(element("sstv-history-list").innerHTML, /91 \(partial\)/);
+});
+
+test("clearing empties the panel", async () => {
+  const { runtime, element } = await loadPanel();
+  runtime.dispatch("sstv", { ts_ms: Date.now(), mode: "PD120", lines: 496, complete: true });
+  assert.match(element("sstv-live-latest").innerHTML, /PD120/);
+
+  runtime.reset("sstv");
+  assert.equal(element("sstv-live-latest").innerHTML, "");
+  assert.equal(element("sstv-status").textContent, "Idle");
+  assert.equal(element("sstv-live-container").style.display, "none");
+});
+
+test("the toggle button follows the rig state", async () => {
+  const { window, element } = await loadPanel();
+  const button = element("sstv-decode-toggle-btn");
+
+  window.syncSstvToggle(true);
+  assert.equal(button.textContent, "Disable SSTV");
+  assert.equal(button.getAttribute("aria-pressed"), "true");
+
+  window.syncSstvToggle(false);
+  assert.equal(button.textContent, "Enable SSTV");
+  assert.equal(button.getAttribute("aria-pressed"), "false");
+});

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/web-fixture.mjs

@@ -29,6 +29,7 @@ const DECODER_REGISTRY = [
   { id: "cw", label: "CW", activation: "toggle", active_modes: ["CW", "CWR"] },
   { id: "sat", label: "SAT", activation: "toggle", active_modes: ["FM"] },
   { id: "wefax", label: "WEFAX", activation: "toggle", active_modes: ["USB"] },
+  { id: "sstv", label: "SSTV", activation: "toggle", active_modes: ["USB", "FM"] },
   { id: "ais", label: "AIS", activation: "toggle", active_modes: ["FM"] },
   { id: "aprs", label: "APRS", activation: "toggle", active_modes: ["FM"] },
   { id: "hf-aprs", label: "HF APRS", activation: "toggle", active_modes: ["USB"] },
@@ -104,7 +105,7 @@ function encodeCbor(value) {
   return Buffer.concat(chunks);
 }
 
-const HISTORY_GROUPS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax"];
+const HISTORY_GROUPS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"];
 
 function assetPath(urlPath) {
   // Every tab route has its own index handler on the server (see api/assets.rs),
@@ -134,6 +135,7 @@ export async function startWebFixture({
   bandplan = {},
   bandplanEnabled = false,
   bandplanUnauthorizedFirst = false,
+  satPasses = null,
 } = {}) {
   const rigItems = ["rig-a", "rig-b"].map((remote) => ({
     remote,
@@ -203,6 +205,7 @@ export async function startWebFixture({
     wspr_decode_enabled: false,
     lrpt_decode_enabled: false,
     wefax_decode_enabled: false,
+    sstv_decode_enabled: false,
     recorder_enabled: false,
     clients: 1,
     rigctl_clients: 0,
@@ -228,6 +231,7 @@ export async function startWebFixture({
     ["/bandplan.json", bandplan],
     ["/api/recorder/status", []],
     ["/api/recorder/files", []],
+    ["/sat_passes", satPasses ?? { satellite_count: 0, passes: [] }],
   ]);
 
   // Flat i8 bins: the shape does not matter, only that frames arrive so the

src/trx-client/trx-frontend/trx-frontend-http/src/api/assets.rs

@@ -101,6 +101,12 @@ pub(crate) async fn statistics_index(req: HttpRequest) -> impl Responder {
     static_asset_response(&req, "text/html; charset=utf-8", c)
 }
 
+#[get("/satellites")]
+pub(crate) async fn satellites_index(req: HttpRequest) -> impl Responder {
+    let c = gz_index_html();
+    static_asset_response(&req, "text/html; charset=utf-8", c)
+}
+
 #[get("/bookmarks")]
 pub(crate) async fn bookmarks_index(req: HttpRequest) -> impl Responder {
     let c = gz_index_html();
@@ -175,21 +181,34 @@ pub(crate) async fn generated_asset(req: HttpRequest, path: web::Path<String>) -
     static_asset_response(&req, content_type, entry)
 }
 
+/// Serve a received SSTV picture out of the local cache.
+#[get("/sstv-images/{filename}")]
+pub(crate) async fn sstv_image(path: web::Path<String>) -> impl Responder {
+    cached_png("sstv", &path.into_inner())
+}
+
 #[get("/images/{filename}")]
 pub(crate) async fn wefax_image(path: web::Path<String>) -> impl Responder {
-    let filename = path.into_inner();
-    // Reject path traversal attempts.
+    cached_png("wefax", &path.into_inner())
+}
+
+/// Read a PNG out of one of the decoder cache directories.
+///
+/// The file name comes from a client, so it is checked rather than trusted: no
+/// separators, no parent references, and a .png suffix. Everything a decoder
+/// writes is named that way, and nothing else in the cache is servable.
+fn cached_png(decoder: &str, filename: &str) -> HttpResponse {
     if filename.contains('/') || filename.contains('\\') || filename.contains("..") {
         return HttpResponse::BadRequest().body("invalid filename");
     }
     if !filename.ends_with(".png") {
         return HttpResponse::BadRequest().body("only .png files are accessible");
     }
-    let dir = dirs::cache_dir()
+    let file_path = dirs::cache_dir()
         .unwrap_or_else(|| std::path::PathBuf::from(".cache"))
         .join("trx-rs")
-        .join("wefax");
-    let file_path = dir.join(&filename);
+        .join(decoder)
+        .join(filename);
     match std::fs::read(&file_path) {
         Ok(data) => HttpResponse::Ok()
             .insert_header((header::CONTENT_TYPE, "image/png"))

src/trx-client/trx-frontend/trx-frontend-http/src/api/decoder.rs

@@ -60,6 +60,7 @@ struct DecodeHistoryPayload {
     ft2: Vec<trx_core::decode::Ft8Message>,
     wspr: Vec<trx_core::decode::WsprMessage>,
     wefax: Vec<trx_core::decode::WefaxMessage>,
+    sstv: Vec<trx_core::decode::SstvMessage>,
 }
 
 impl DecodeHistoryPayload {
@@ -74,6 +75,7 @@ impl DecodeHistoryPayload {
             + self.ft2.len()
             + self.wspr.len()
             + self.wefax.len()
+            + self.sstv.len()
     }
 }
 
@@ -93,6 +95,7 @@ fn collect_decode_history(
         ft2: crate::server::audio::snapshot_ft2_history(context, rig_filter),
         wspr: crate::server::audio::snapshot_wspr_history(context, rig_filter),
         wefax: crate::server::audio::snapshot_wefax_history(context, rig_filter),
+        sstv: crate::server::audio::snapshot_sstv_history(context, rig_filter),
     }
 }
 
@@ -451,10 +454,40 @@ pub async fn toggle_wefax_decode(
     .await
 }
 
+#[post("/toggle_sstv_decode")]
+pub async fn toggle_sstv_decode(
+    query: web::Query<RemoteQuery>,
+    state: web::Data<watch::Receiver<RigState>>,
+    context: web::Data<Arc<FrontendRuntimeContext>>,
+    rig_tx: web::Data<mpsc::Sender<RigRequest>>,
+) -> Result<HttpResponse, Error> {
+    let q = query.into_inner();
+    let rig_state = resolve_rig_state(q.remote.as_deref(), &context, state.get_ref());
+    send_command(
+        &rig_tx,
+        RigCommand::SetSstvDecodeEnabled(!rig_state.decoders.sstv_decode_enabled),
+        q.remote,
+    )
+    .await
+}
+
 // ============================================================================
 // Decoder clear endpoints
 // ============================================================================
 
+#[post("/clear_sstv_decode")]
+pub async fn clear_sstv_decode(
+    query: web::Query<RemoteQuery>,
+    rig_tx: web::Data<mpsc::Sender<RigRequest>>,
+) -> Result<HttpResponse, Error> {
+    send_command(
+        &rig_tx,
+        RigCommand::ResetSstvDecoder,
+        query.into_inner().remote,
+    )
+    .await
+}
+
 #[post("/clear_wefax_decode")]
 pub async fn clear_wefax_decode(
     query: web::Query<RemoteQuery>,

src/trx-client/trx-frontend/trx-frontend-http/src/api/mod.rs

@@ -591,6 +591,7 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(decoder::toggle_wspr_decode)
         .service(decoder::toggle_lrpt_decode)
         .service(decoder::toggle_wefax_decode)
+        .service(decoder::toggle_sstv_decode)
         .service(decoder::clear_ais_decode)
         .service(decoder::clear_vdes_decode)
         .service(decoder::clear_aprs_decode)
@@ -602,6 +603,7 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(decoder::clear_wspr_decode)
         .service(decoder::clear_lrpt_decode)
         .service(decoder::clear_wefax_decode)
+        .service(decoder::clear_sstv_decode)
         // Bookmark CRUD
         .service(bookmarks::list_bookmarks)
         .service(bookmarks::create_bookmark)
@@ -637,6 +639,7 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(assets::recorder_index)
         .service(assets::settings_index)
         .service(assets::about_index)
+        .service(assets::satellites_index)
         .service(assets::statistics_index)
         .service(assets::bookmarks_index)
         .service(assets::favicon)
@@ -645,6 +648,7 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(assets::style_css)
         .service(assets::themes_css)
         .service(assets::wefax_image)
+        .service(assets::sstv_image)
         .service(assets::bandplan_json)
         // Vendored DSEG14 Classic font
         .service(assets::dseg14_classic_woff2)

src/trx-client/trx-frontend/trx-frontend-http/src/audio.rs

@@ -24,8 +24,8 @@ use tracing::warn;
 use uuid::Uuid;
 
 use trx_core::decode::{
-    AisMessage, AprsPacket, CwEvent, DecodedMessage, Ft8Message, VdesMessage, WefaxMessage,
-    WsprMessage,
+    AisMessage, AprsPacket, CwEvent, DecodedMessage, Ft8Message, SstvMessage, VdesMessage,
+    WefaxMessage, WsprMessage,
 };
 use trx_frontend::FrontendRuntimeContext;
 
@@ -335,6 +335,43 @@ fn record_wefax(context: &FrontendRuntimeContext, mut msg: WefaxMessage) {
     }
 }
 
+/// Store a received picture, saving the PNG the server sent into the local
+/// cache so `/images/` can serve it back.
+fn record_sstv(context: &FrontendRuntimeContext, mut msg: SstvMessage) {
+    if let Some(ref data) = msg.png_data {
+        if let Some(ref path) = msg.path {
+            if let Some(filename) = std::path::Path::new(path).file_name() {
+                let dir = dirs::cache_dir()
+                    .unwrap_or_else(|| std::path::PathBuf::from(".cache"))
+                    .join("trx-rs")
+                    .join("sstv");
+                if std::fs::create_dir_all(&dir).is_ok() {
+                    if let Ok(bytes) = base64::engine::general_purpose::STANDARD.decode(data) {
+                        let local_path = dir.join(filename);
+                        if let Err(e) = std::fs::write(&local_path, &bytes) {
+                            tracing::warn!("SSTV: failed to save local image: {}", e);
+                        }
+                    }
+                }
+            }
+        }
+    }
+    // The picture itself is on disk now; keeping a megabyte of base64 per
+    // entry in memory is what the history does not need.
+    msg.png_data = None;
+
+    let rig_id = msg.rig_id.clone().or_else(|| active_rig_id(context));
+    let mut history = context
+        .decode_history
+        .sstv
+        .lock()
+        .expect("sstv history mutex poisoned");
+    history.push_back((Instant::now(), rig_id, msg));
+    while history.len() > 100 {
+        history.pop_front();
+    }
+}
+
 /// Returns `true` if the entry's rig_id matches the optional filter.
 /// `None` filter means "all rigs".
 fn matches_rig_filter(entry_rig: Option<&str>, filter: Option<&str>) -> bool {
@@ -526,6 +563,31 @@ pub fn snapshot_wefax_history(
         .collect()
 }
 
+pub fn snapshot_sstv_history(
+    context: &FrontendRuntimeContext,
+    rig_filter: Option<&str>,
+) -> Vec<SstvMessage> {
+    let history = context
+        .decode_history
+        .sstv
+        .lock()
+        .expect("sstv history mutex poisoned");
+    history
+        .iter()
+        .filter(|(_, rid, _)| matches_rig_filter(rid.as_deref(), rig_filter))
+        .map(|(_, _, msg)| msg.clone())
+        .collect()
+}
+
+pub fn clear_sstv_history(context: &FrontendRuntimeContext) {
+    let mut history = context
+        .decode_history
+        .sstv
+        .lock()
+        .expect("sstv history mutex poisoned");
+    history.clear();
+}
+
 pub fn clear_wefax_history(context: &FrontendRuntimeContext) {
     let mut history = context
         .decode_history
@@ -650,6 +712,9 @@ pub fn start_decode_history_collector(context: Arc<FrontendRuntimeContext>) {
                     DecodedMessage::Wspr(msg) => record_wspr(&context, msg),
                     DecodedMessage::Wefax(msg) => record_wefax(&context, msg),
                     DecodedMessage::WefaxProgress(_) => {}
+                    DecodedMessage::Sstv(msg) => record_sstv(&context, msg),
+                    // Progress is for watching, not for keeping.
+                    DecodedMessage::SstvProgress(_) => {}
                     DecodedMessage::LrptImage(_) => {}
                     DecodedMessage::LrptProgress(_) => {}
                 },

src/trx-core/src/audio.rs

@@ -74,6 +74,11 @@ pub const AUDIO_MSG_LRPT_PROGRESS: u8 = 0x18;
 pub const AUDIO_MSG_WEFAX_DECODE: u8 = 0x19;
 /// Server → client: WEFAX decode progress (JSON `DecodedMessage::WefaxProgress`).
 pub const AUDIO_MSG_WEFAX_PROGRESS: u8 = 0x1A;
+/// Server → client: SSTV received picture (JSON `DecodedMessage::Sstv`).
+pub const AUDIO_MSG_SSTV_DECODE: u8 = 0x1B;
+/// Server → client: SSTV decode progress, one line at a time
+/// (JSON `DecodedMessage::SstvProgress`).
+pub const AUDIO_MSG_SSTV_PROGRESS: u8 = 0x1C;
 
 /// Maximum payload size for normal messages (1 MB).
 const MAX_PAYLOAD_SIZE: u32 = 1_048_576;

src/trx-core/src/decode.rs

@@ -36,6 +36,10 @@ pub enum DecodedMessage {
     Wefax(WefaxMessage),
     #[serde(rename = "wefax_progress")]
     WefaxProgress(WefaxProgress),
+    #[serde(rename = "sstv")]
+    Sstv(SstvMessage),
+    #[serde(rename = "sstv_progress")]
+    SstvProgress(SstvProgress),
 }
 
 impl DecodedMessage {
@@ -52,6 +56,8 @@ impl DecodedMessage {
             Self::LrptProgress(m) => m.rig_id = Some(id),
             Self::Wefax(m) => m.rig_id = Some(id),
             Self::WefaxProgress(m) => m.rig_id = Some(id),
+            Self::Sstv(m) => m.rig_id = Some(id),
+            Self::SstvProgress(m) => m.rig_id = Some(id),
         }
     }
 
@@ -68,6 +74,8 @@ impl DecodedMessage {
             Self::LrptProgress(m) => m.rig_id.as_deref(),
             Self::Wefax(m) => m.rig_id.as_deref(),
             Self::WefaxProgress(m) => m.rig_id.as_deref(),
+            Self::Sstv(m) => m.rig_id.as_deref(),
+            Self::SstvProgress(m) => m.rig_id.as_deref(),
         }
     }
 }
@@ -319,3 +327,52 @@ pub struct WefaxProgress {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub state: Option<String>,
 }
+
+/// A received SSTV picture, complete or cut short.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SstvMessage {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub rig_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub ts_ms: Option<i64>,
+    /// VIS code the transmission announced itself with.
+    pub vis: u8,
+    /// Mode name, e.g. "Martin M1".
+    pub mode: String,
+    pub width: u16,
+    pub height: u16,
+    /// Image lines actually received, which is the height only if the whole
+    /// frame arrived.
+    pub lines: u16,
+    /// Whether reception reached the bottom of the frame.
+    pub complete: bool,
+    /// Filesystem path to the saved PNG, when one was written.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub path: Option<String>,
+    /// Base64-encoded PNG for the trip to a client. Populated when sending and
+    /// stripped before the message is stored in history, which would otherwise
+    /// hold a megabyte per picture.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub png_data: Option<String>,
+}
+
+/// A picture arriving, emitted per line so it can be watched.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SstvProgress {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub rig_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub ts_ms: Option<i64>,
+    pub vis: u8,
+    pub mode: String,
+    pub width: u16,
+    pub height: u16,
+    /// Index of the line this update carries.
+    pub line: u16,
+    /// Base64-encoded RGB triples for that one line.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub line_data: Option<String>,
+    /// Decoder state for display, e.g. "Receiving Martin M1".
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub state: Option<String>,
+}

src/trx-core/src/rig/command.rs

@@ -33,6 +33,7 @@ pub enum RigCommand {
     SetWsprDecodeEnabled(bool),
     SetLrptDecodeEnabled(bool),
     SetWefaxDecodeEnabled(bool),
+    SetSstvDecodeEnabled(bool),
     ResetAprsDecoder,
     ResetHfAprsDecoder,
     ResetCwDecoder,
@@ -42,6 +43,7 @@ pub enum RigCommand {
     ResetWsprDecoder,
     ResetLrptDecoder,
     ResetWefaxDecoder,
+    ResetSstvDecoder,
     SetBandwidth(u32),
     SetSdrGain(f64),
     SetSdrLnaGain(f64),

src/trx-core/src/rig/controller/handlers.rs

@@ -462,6 +462,8 @@ pub fn command_from_rig_command(cmd: RigCommand) -> Box<dyn RigCommandHandler> {
         | RigCommand::ResetLrptDecoder
         | RigCommand::SetWefaxDecodeEnabled(_)
         | RigCommand::ResetWefaxDecoder
+        | RigCommand::SetSstvDecodeEnabled(_)
+        | RigCommand::ResetSstvDecoder
         | RigCommand::SetBandwidth(_)
         | RigCommand::SetSdrGain(_)
         | RigCommand::SetSdrLnaGain(_)

src/trx-core/src/rig/state.rs

@@ -34,6 +34,8 @@ pub struct DecoderConfig {
     #[serde(default)]
     pub wefax_decode_enabled: bool,
     #[serde(default)]
+    pub sstv_decode_enabled: bool,
+    #[serde(default)]
     pub recorder_enabled: bool,
 }
 
@@ -62,6 +64,8 @@ pub struct DecoderResetSeqs {
     pub lrpt_decode_reset_seq: u64,
     #[serde(default, skip_serializing)]
     pub wefax_decode_reset_seq: u64,
+    #[serde(default, skip_serializing)]
+    pub sstv_decode_reset_seq: u64,
 }
 
 /// Simple transceiver state representation held by the rig task.

src/trx-protocol/src/decoders.rs

@@ -139,6 +139,16 @@ pub const DECODER_REGISTRY: &[DecoderDescriptor] = &[
         background_decode: false,
         bookmark_selectable: true,
     },
+    DecoderDescriptor {
+        id: "sstv",
+        label: "SSTV",
+        activation: DecoderActivation::Toggle,
+        // SSTV is sent on sideband on HF and on FM simplex on VHF, and the
+        // decoder cares only about the audio it is handed.
+        active_modes: &["USB", "LSB", "FM", "AM", "DIG"],
+        background_decode: false,
+        bookmark_selectable: true,
+    },
 ];
 
 // ============================================================================

src/trx-protocol/src/mapping.rs

@@ -122,7 +122,8 @@ define_command_mapping! {
         ResetFt2Decoder      <=> ResetFt2Decoder,
         ResetWsprDecoder     <=> ResetWsprDecoder,
         ResetLrptDecoder     <=> ResetLrptDecoder,
-        ResetWefaxDecoder    <=> ResetWefaxDecoder;
+        ResetWefaxDecoder    <=> ResetWefaxDecoder,
+        ResetSstvDecoder     <=> ResetSstvDecoder;
 
     // ── Single-field struct <=> tuple ────────────────────────────────
     field:
@@ -140,6 +141,7 @@ define_command_mapping! {
         SetWsprDecodeEnabled  { enabled }        <=> SetWsprDecodeEnabled,
         SetLrptDecodeEnabled  { enabled }        <=> SetLrptDecodeEnabled,
         SetWefaxDecodeEnabled { enabled }        <=> SetWefaxDecodeEnabled,
+        SetSstvDecodeEnabled  { enabled }        <=> SetSstvDecodeEnabled,
         SetBandwidth          { bandwidth_hz }   <=> SetBandwidth,
         SetSdrGain            { gain_db }        <=> SetSdrGain,
         SetSdrLnaGain         { gain_db }        <=> SetSdrLnaGain,

src/trx-protocol/src/types.rs

@@ -73,6 +73,9 @@ pub enum ClientCommand {
     SetWefaxDecodeEnabled {
         enabled: bool,
     },
+    SetSstvDecodeEnabled {
+        enabled: bool,
+    },
     ResetAprsDecoder,
     ResetHfAprsDecoder,
     ResetCwDecoder,
@@ -82,6 +85,7 @@ pub enum ClientCommand {
     ResetWsprDecoder,
     ResetLrptDecoder,
     ResetWefaxDecoder,
+    ResetSstvDecoder,
     SetBandwidth {
         bandwidth_hz: u32,
     },

src/trx-server/Cargo.toml

@@ -41,6 +41,7 @@ trx-cw = { path = "../decoders/trx-cw" }
 trx-decode-log = { path = "../decoders/trx-decode-log" }
 trx-ftx = { path = "../decoders/trx-ftx" }
 trx-wefax = { path = "../decoders/trx-wefax" }
+trx-sstv = { path = "../decoders/trx-sstv" }
 trx-wspr = { path = "../decoders/trx-wspr" }
 trx-wxsat = { path = "../decoders/trx-wxsat" }
 trx-protocol = { path = "../trx-protocol" }

src/trx-server/src/audio.rs

@@ -30,10 +30,11 @@ use trx_core::audio::{
     write_vchan_uuid_msg, AudioStreamInfo, AUDIO_MSG_AIS_DECODE, AUDIO_MSG_APRS_DECODE,
     AUDIO_MSG_CW_DECODE, AUDIO_MSG_FT2_DECODE, AUDIO_MSG_FT4_DECODE, AUDIO_MSG_FT8_DECODE,
     AUDIO_MSG_HF_APRS_DECODE, AUDIO_MSG_HISTORY_COMPRESSED, AUDIO_MSG_LRPT_IMAGE,
-    AUDIO_MSG_LRPT_PROGRESS, AUDIO_MSG_RX_FRAME, AUDIO_MSG_STREAM_INFO, AUDIO_MSG_TX_FRAME,
-    AUDIO_MSG_VCHAN_ALLOCATED, AUDIO_MSG_VCHAN_BW, AUDIO_MSG_VCHAN_DESTROYED, AUDIO_MSG_VCHAN_FREQ,
-    AUDIO_MSG_VCHAN_MODE, AUDIO_MSG_VCHAN_REMOVE, AUDIO_MSG_VCHAN_SUB, AUDIO_MSG_VCHAN_UNSUB,
-    AUDIO_MSG_VDES_DECODE, AUDIO_MSG_WEFAX_DECODE, AUDIO_MSG_WEFAX_PROGRESS, AUDIO_MSG_WSPR_DECODE,
+    AUDIO_MSG_LRPT_PROGRESS, AUDIO_MSG_RX_FRAME, AUDIO_MSG_SSTV_DECODE, AUDIO_MSG_SSTV_PROGRESS,
+    AUDIO_MSG_STREAM_INFO, AUDIO_MSG_TX_FRAME, AUDIO_MSG_VCHAN_ALLOCATED, AUDIO_MSG_VCHAN_BW,
+    AUDIO_MSG_VCHAN_DESTROYED, AUDIO_MSG_VCHAN_FREQ, AUDIO_MSG_VCHAN_MODE, AUDIO_MSG_VCHAN_REMOVE,
+    AUDIO_MSG_VCHAN_SUB, AUDIO_MSG_VCHAN_UNSUB, AUDIO_MSG_VDES_DECODE, AUDIO_MSG_WEFAX_DECODE,
+    AUDIO_MSG_WEFAX_PROGRESS, AUDIO_MSG_WSPR_DECODE,
 };
 #[cfg(test)]
 use trx_core::decode::{AisMessage, AprsPacket, CwEvent};
@@ -292,6 +293,11 @@ fn build_history_blob(histories: &DecoderHistories) -> (Vec<u8>, usize) {
         DecodedMessage::Wefax,
         AUDIO_MSG_WEFAX_DECODE
     );
+    push_history!(
+        histories.snapshot_sstv_history(),
+        DecodedMessage::Sstv,
+        AUDIO_MSG_SSTV_DECODE
+    );
 
     (blob, count)
 }
@@ -2444,6 +2450,244 @@ pub async fn run_wefax_decoder(
     info!("WEFAX decoder stopped");
 }
 
+// ---------------------------------------------------------------------------
+// SSTV decoder task
+// ---------------------------------------------------------------------------
+
+/// Turn a decoded picture into the message clients receive, saving the PNG on
+/// the way. The picture travels as base64 so a client on another machine has
+/// it without a second request; the server keeps its own copy on disk.
+fn sstv_message(
+    image: &trx_sstv::SstvImage,
+    output_dir: &std::path::Path,
+    freq_hz: u64,
+) -> DecodedMessage {
+    let path = match image.save_png(output_dir, freq_hz) {
+        Ok(path) => Some(path.to_string_lossy().into_owned()),
+        Err(e) => {
+            warn!("SSTV: failed to save image: {}", e);
+            None
+        }
+    };
+    let png_data = image.to_png_base64().ok();
+    DecodedMessage::Sstv(trx_core::decode::SstvMessage {
+        rig_id: None,
+        ts_ms: Some(image.started_ms),
+        vis: image.vis,
+        mode: image.mode.to_string(),
+        width: image.width,
+        height: image.height,
+        lines: image.lines,
+        complete: image.complete,
+        path,
+        png_data,
+    })
+}
+
+/// Run the SSTV decoder task. Processes PCM when enabled and the rig mode is
+/// one SSTV is sent in.
+#[allow(clippy::too_many_arguments)]
+pub async fn run_sstv_decoder(
+    sample_rate: u32,
+    channels: u16,
+    mut pcm_rx: broadcast::Receiver<Vec<f32>>,
+    mut state_rx: watch::Receiver<RigState>,
+    decode_tx: broadcast::Sender<DecodedMessage>,
+    histories: Arc<DecoderHistories>,
+    output_dir: std::path::PathBuf,
+) {
+    use trx_sstv::{SstvConfig, SstvDecoder, SstvEvent};
+
+    info!("SSTV decoder started ({}Hz, {} ch)", sample_rate, channels);
+
+    let mut decoder = SstvDecoder::new(sample_rate, SstvConfig::default());
+    let mut was_active = false;
+    let mut last_reset_seq: u64 = 0;
+
+    let is_sstv_mode = |mode: &RigMode| {
+        matches!(
+            mode,
+            RigMode::USB | RigMode::LSB | RigMode::FM | RigMode::AM | RigMode::DIG
+        )
+    };
+
+    // Reset returns any picture in progress rather than discarding it: a
+    // half-received frame is still worth keeping.
+    macro_rules! flush {
+        ($decoder:expr) => {
+            for event in $decoder.reset() {
+                if let SstvEvent::Complete(image) = event {
+                    // Read the dial now rather than caching it: the picture is
+                    // named for where it was received.
+                    let freq_hz = state_rx.borrow().status.freq.hz;
+                    let msg = sstv_message(&image, &output_dir, freq_hz);
+                    if let DecodedMessage::Sstv(ref stored) = msg {
+                        histories.record_sstv_message(stored.clone());
+                    }
+                    let _ = decode_tx.send(msg);
+                }
+            }
+        };
+    }
+
+    let mut active = state_rx.borrow().decoders.sstv_decode_enabled
+        && is_sstv_mode(&state_rx.borrow().status.mode);
+
+    loop {
+        if !active {
+            match state_rx.changed().await {
+                Ok(()) => {
+                    let state = state_rx.borrow();
+                    active = state.decoders.sstv_decode_enabled && is_sstv_mode(&state.status.mode);
+                    if active {
+                        pcm_rx = pcm_rx.resubscribe();
+                    }
+                }
+                Err(_) => break,
+            }
+            continue;
+        }
+
+        tokio::select! {
+            recv = pcm_rx.recv() => {
+                match recv {
+                    Ok(frame) => {
+                        let (process_enabled, reset_seq) = {
+                            let state = state_rx.borrow();
+                            (
+                                state.decoders.sstv_decode_enabled
+                                    && is_sstv_mode(&state.status.mode),
+                                state.reset_seqs.sstv_decode_reset_seq,
+                            )
+                        };
+
+                        if reset_seq != last_reset_seq {
+                            last_reset_seq = reset_seq;
+                            flush!(decoder);
+                            info!("SSTV decoder reset (seq={})", last_reset_seq);
+                            pcm_rx = pcm_rx.resubscribe();
+                            continue;
+                        }
+
+                        if !process_enabled {
+                            if was_active {
+                                flush!(decoder);
+                                was_active = false;
+                            }
+                            active = false;
+                            continue;
+                        }
+
+                        let mono = if channels > 1 {
+                            let num_frames = frame.len() / channels as usize;
+                            let mut mono = Vec::with_capacity(num_frames);
+                            for i in 0..num_frames {
+                                mono.push(frame[i * channels as usize]);
+                            }
+                            mono
+                        } else {
+                            frame
+                        };
+
+                        was_active = true;
+                        let events = tokio::task::block_in_place(|| {
+                            let _span = info_span!("sstv_decode").entered();
+                            decoder.process_samples(&mono)
+                        });
+
+                        let latest_reset_seq = state_rx.borrow().reset_seqs.sstv_decode_reset_seq;
+                        if latest_reset_seq != reset_seq {
+                            last_reset_seq = latest_reset_seq;
+                            flush!(decoder);
+                            info!("SSTV decoder reset (seq={})", last_reset_seq);
+                            pcm_rx = pcm_rx.resubscribe();
+                            continue;
+                        }
+
+                        for event in events {
+                            match event {
+                                SstvEvent::Started { vis, mode, width, height } => {
+                                    info!("SSTV: receiving {} (VIS {})", mode, vis);
+                                    let _ = decode_tx.send(DecodedMessage::SstvProgress(
+                                        trx_core::decode::SstvProgress {
+                                            rig_id: None,
+                                            ts_ms: Some(now_ms()),
+                                            vis,
+                                            mode: mode.to_string(),
+                                            width,
+                                            height,
+                                            line: 0,
+                                            line_data: None,
+                                            state: Some(format!("Receiving {mode}")),
+                                        },
+                                    ));
+                                }
+                                SstvEvent::Row { line, rgb } => {
+                                    // One row per message: the picture is meant
+                                    // to be watched arriving, and a row of a
+                                    // 640-wide mode is under 2 kB.
+                                    let _ = decode_tx.send(DecodedMessage::SstvProgress(
+                                        trx_core::decode::SstvProgress {
+                                            rig_id: None,
+                                            ts_ms: Some(now_ms()),
+                                            vis: 0,
+                                            mode: String::new(),
+                                            width: 0,
+                                            height: 0,
+                                            line,
+                                            line_data: Some({
+                                                use base64::Engine as _;
+                                                base64::engine::general_purpose::STANDARD
+                                                    .encode(&rgb)
+                                            }),
+                                            state: None,
+                                        },
+                                    ));
+                                }
+                                SstvEvent::Complete(image) => {
+                                    info!(
+                                        "SSTV: {} picture, {} of {} lines",
+                                        image.mode, image.lines, image.height
+                                    );
+                                    let freq_hz = state_rx.borrow().status.freq.hz;
+                                    let msg = sstv_message(&image, &output_dir, freq_hz);
+                                    if let DecodedMessage::Sstv(ref stored) = msg {
+                                        histories.record_sstv_message(stored.clone());
+                                    }
+                                    let _ = decode_tx.send(msg);
+                                }
+                            }
+                        }
+                    }
+                    Err(broadcast::error::RecvError::Lagged(n)) => {
+                        warn!("SSTV decoder: dropped {} PCM frames", n);
+                    }
+                    Err(broadcast::error::RecvError::Closed) => break,
+                }
+            }
+            changed = state_rx.changed() => {
+                match changed {
+                    Ok(()) => {
+                        let state = state_rx.borrow();
+                        active = state.decoders.sstv_decode_enabled
+                            && is_sstv_mode(&state.status.mode);
+                    }
+                    Err(_) => break,
+                }
+            }
+        }
+    }
+    info!("SSTV decoder stopped");
+}
+
+/// Milliseconds since the epoch.
+fn now_ms() -> i64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_millis() as i64
+}
+
 // ---------------------------------------------------------------------------
 // Virtual-channel audio support
 // ---------------------------------------------------------------------------
@@ -3078,6 +3322,8 @@ async fn handle_audio_client(
                                 DecodedMessage::LrptProgress(_) => AUDIO_MSG_LRPT_PROGRESS,
                                 DecodedMessage::Wefax(_) => AUDIO_MSG_WEFAX_DECODE,
                                 DecodedMessage::WefaxProgress(_) => AUDIO_MSG_WEFAX_PROGRESS,
+                                DecodedMessage::Sstv(_) => AUDIO_MSG_SSTV_DECODE,
+                                DecodedMessage::SstvProgress(_) => AUDIO_MSG_SSTV_PROGRESS,
                             };
                             if let Ok(json) = serde_json::to_vec(&msg) {
                                 if let Err(e) = write_audio_msg(&mut writer_for_rx, msg_type, &json).await {
@@ -3110,6 +3356,8 @@ async fn handle_audio_client(
                                 DecodedMessage::LrptProgress(_) => AUDIO_MSG_LRPT_PROGRESS,
                                 DecodedMessage::Wefax(_) => AUDIO_MSG_WEFAX_DECODE,
                                 DecodedMessage::WefaxProgress(_) => AUDIO_MSG_WEFAX_PROGRESS,
+                                DecodedMessage::Sstv(_) => AUDIO_MSG_SSTV_DECODE,
+                                DecodedMessage::SstvProgress(_) => AUDIO_MSG_SSTV_PROGRESS,
                             };
                             if let Ok(json) = serde_json::to_vec(&msg) {
                                 if let Err(e) = write_audio_msg(&mut writer_for_rx, msg_type, &json).await {

src/trx-server/src/decoder_history.rs

@@ -11,7 +11,8 @@ use std::time::Instant;
 
 use base64::Engine as _;
 use trx_core::decode::{
-    AisMessage, AprsPacket, CwEvent, Ft8Message, LrptImage, VdesMessage, WefaxMessage, WsprMessage,
+    AisMessage, AprsPacket, CwEvent, Ft8Message, LrptImage, SstvMessage, VdesMessage, WefaxMessage,
+    WsprMessage,
 };
 
 use crate::history_policy::{
@@ -36,6 +37,7 @@ pub struct DecoderHistories {
     pub wspr: Mutex<VecDeque<(Instant, WsprMessage)>>,
     pub lrpt: Mutex<VecDeque<(Instant, LrptImage)>>,
     pub wefax: Mutex<VecDeque<(Instant, WefaxMessage)>>,
+    pub sstv: Mutex<VecDeque<(Instant, SstvMessage)>>,
     /// Approximate total entry count across all decoders, maintained
     /// atomically so `estimated_total_count()` avoids 11 lock acquisitions.
     total_count: AtomicUsize,
@@ -55,6 +57,7 @@ impl DecoderHistories {
             wspr: Mutex::new(VecDeque::new()),
             lrpt: Mutex::new(VecDeque::new()),
             wefax: Mutex::new(VecDeque::new()),
+            sstv: Mutex::new(VecDeque::new()),
             total_count: AtomicUsize::new(0),
         })
     }
@@ -412,6 +415,42 @@ impl DecoderHistories {
         self.adjust_total_count(before, 0);
     }
 
+    // --- SSTV ---
+
+    fn prune_sstv(history: &mut VecDeque<(Instant, SstvMessage)>) {
+        prune_by_age(history, HISTORY_RETENTION, Instant::now());
+    }
+
+    pub fn record_sstv_message(&self, mut msg: SstvMessage) {
+        if msg.ts_ms.is_none() {
+            msg.ts_ms = Some(current_timestamp_ms());
+        }
+        // The picture is on disk; a megabyte of base64 per entry is not what
+        // the history is for.
+        msg.png_data = None;
+        let mut h = lock_or_recover(&self.sstv, "sstv_history");
+        let before = h.len();
+        h.push_back((Instant::now(), msg));
+        Self::prune_sstv(&mut h);
+        enforce_capacity(&mut h, MAX_HISTORY_ENTRIES);
+        self.adjust_total_count(before, h.len());
+    }
+
+    pub fn snapshot_sstv_history(&self) -> Vec<SstvMessage> {
+        let mut h = lock_or_recover(&self.sstv, "sstv_history");
+        let before = h.len();
+        Self::prune_sstv(&mut h);
+        self.adjust_total_count(before, h.len());
+        h.iter().map(|(_, m)| m.clone()).collect()
+    }
+
+    pub fn clear_sstv_history(&self) {
+        let mut h = lock_or_recover(&self.sstv, "sstv_history");
+        let before = h.len();
+        h.clear();
+        self.adjust_total_count(before, 0);
+    }
+
     // --- WEFAX ---
 
     fn prune_wefax(history: &mut VecDeque<(Instant, WefaxMessage)>) {
@@ -483,7 +522,8 @@ impl DecoderHistories {
             + lock_or_recover(&self.ft2, "ft2_history").len()
             + lock_or_recover(&self.wspr, "wspr_history").len()
             + lock_or_recover(&self.lrpt, "lrpt_history").len()
-            + lock_or_recover(&self.wefax, "wefax_history").len();
+            + lock_or_recover(&self.wefax, "wefax_history").len()
+            + lock_or_recover(&self.sstv, "sstv_history").len();
         self.total_count.store(total, Ordering::Relaxed);
     }
 }

src/trx-server/src/history_store.rs

@@ -19,7 +19,8 @@ use pickledb::{PickleDb, PickleDbDumpPolicy, SerializationMethod};
 use serde::{de::DeserializeOwned, Deserialize, Serialize};
 
 use trx_core::decode::{
-    AisMessage, AprsPacket, CwEvent, Ft8Message, LrptImage, VdesMessage, WefaxMessage, WsprMessage,
+    AisMessage, AprsPacket, CwEvent, Ft8Message, LrptImage, SstvMessage, VdesMessage, WefaxMessage,
+    WsprMessage,
 };
 
 use crate::audio::DecoderHistories;
@@ -158,6 +159,11 @@ pub fn load_all(db: &PickleDb, rig_id: &str, histories: &Arc<DecoderHistories>)
             h.push_back(e);
         }
     }
+    if let Ok(mut h) = histories.sstv.lock() {
+        for e in load_key::<SstvMessage>(db, &k("sstv")) {
+            h.push_back(e);
+        }
+    }
     histories.recalculate_total_count();
 }
 
@@ -223,6 +229,11 @@ pub fn flush_all(db: &mut PickleDb, rig_id: &str, histories: &Arc<DecoderHistori
         drop(h);
         save_key(db, &k("wefax"), &snapshot);
     }
+    if let Ok(h) = histories.sstv.lock() {
+        let snapshot = h.clone();
+        drop(h);
+        save_key(db, &k("sstv"), &snapshot);
+    }
     let _ = db.dump();
 }
 

src/trx-server/src/main.rs

@@ -834,6 +834,25 @@ fn spawn_rig_audio_stack(
                 _ = wait_for_shutdown(wefax_shutdown_rx) => {}
             }
         }));
+
+        // Spawn SSTV decoder task
+        let sstv_pcm_rx = pcm_tx.subscribe();
+        let sstv_state_rx = state_rx.clone();
+        let sstv_decode_tx = decode_tx.clone();
+        let sstv_sr = rig_cfg.audio.sample_rate;
+        let sstv_ch = rig_cfg.audio.channels;
+        let sstv_shutdown_rx = shutdown_rx.clone();
+        let sstv_histories = histories.clone();
+        let sstv_output_dir = dirs::cache_dir()
+            .unwrap_or_else(|| std::path::PathBuf::from(".cache"))
+            .join("trx-rs")
+            .join("sstv");
+        handles.push(tokio::spawn(async move {
+            tokio::select! {
+                _ = audio::run_sstv_decoder(sstv_sr, sstv_ch as u16, sstv_pcm_rx, sstv_state_rx, sstv_decode_tx, sstv_histories, sstv_output_dir) => {}
+                _ = wait_for_shutdown(sstv_shutdown_rx) => {}
+            }
+        }));
     }
 
     if rig_cfg.audio.tx_enabled {

src/trx-server/src/rig_task.rs

@@ -657,6 +657,18 @@ async fn process_command(
             let _ = ctx.state_tx.send(ctx.state.clone());
             return snapshot_from(ctx.state);
         }
+        RigCommand::SetSstvDecodeEnabled(en) => {
+            ctx.state.decoders.sstv_decode_enabled = en;
+            info!("SSTV decode {}", if en { "enabled" } else { "disabled" });
+            let _ = ctx.state_tx.send(ctx.state.clone());
+            return snapshot_from(ctx.state);
+        }
+        RigCommand::ResetSstvDecoder => {
+            ctx.histories.clear_sstv_history();
+            ctx.state.reset_seqs.sstv_decode_reset_seq += 1;
+            let _ = ctx.state_tx.send(ctx.state.clone());
+            return snapshot_from(ctx.state);
+        }
         RigCommand::SetBandwidth(hz) => {
             if let Some(sdr) = ctx.rig.as_sdr() {
                 if let Err(e) = sdr.set_bandwidth(hz).await {