[fix](trx-rs): remove wfm denoise and default stereo audio

Co-authored-by: Codex <codex@openai.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

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

@@ -1259,12 +1259,6 @@ function render(update) {
         saveSetting("wfmAudioMode", nextMode);
       }
     }
-    if (wfmDenoiseBtn && typeof update.filter.wfm_denoise === "boolean") {
-      const on = update.filter.wfm_denoise;
-      wfmDenoiseBtn.textContent = on ? "On" : "Off";
-      wfmDenoiseBtn.style.borderColor = on ? "" : "var(--accent-warn, #f0a500)";
-      wfmDenoiseBtn.style.color = on ? "" : "var(--accent-warn, #f0a500)";
-    }
     if (wfmStFlagEl && typeof update.filter.wfm_stereo_detected === "boolean") {
       const detected = update.filter.wfm_stereo_detected;
       wfmStFlagEl.textContent = detected ? "ST" : "MO";
@@ -2566,7 +2560,6 @@ const wfmControlsCol = document.getElementById("wfm-controls-col");
 const wfmDeemphasisEl = document.getElementById("wfm-deemphasis");
 const wfmAudioModeEl = document.getElementById("wfm-audio-mode");
 const wfmStFlagEl = document.getElementById("wfm-st-flag");
-const wfmDenoiseBtn = document.getElementById("wfm-denoise-btn");
 
 // Hide audio row if audio is not configured on the server
 fetch("/audio", { method: "GET" }).then((r) => {
@@ -2610,12 +2603,6 @@ if (wfmDeemphasisEl) {
     postPath(`/set_wfm_deemphasis?us=${encodeURIComponent(wfmDeemphasisEl.value)}`).catch(() => {});
   });
 }
-if (wfmDenoiseBtn) {
-  wfmDenoiseBtn.addEventListener("click", () => {
-    postPath("/toggle_wfm_denoise").catch(() => {});
-  });
-}
-
 function updateWfmControls() {
   if (!wfmControlsCol) return;
   const mode = (modeEl && modeEl.value ? modeEl.value : "").toUpperCase();

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

@@ -168,9 +168,6 @@
                   <label class="wfm-control wfm-st-flag-wrap" aria-label="Stereo pilot status">
                     <span id="wfm-st-flag" class="wfm-st-flag wfm-st-flag-mono">MO</span>
                   </label>
-                  <label class="wfm-control">Denoise
-                    <button id="wfm-denoise-btn" type="button" class="status-input toggle-btn toggle-on">On</button>
-                  </label>
                 </div>
                 <div class="label"><span>WFM</span></div>
               </div>

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

@@ -499,21 +499,6 @@ pub async fn set_wfm_stereo(
     send_command(&rig_tx, RigCommand::SetWfmStereo(query.enabled)).await
 }
 
-#[post("/toggle_wfm_denoise")]
-pub async fn toggle_wfm_denoise(
-    state: web::Data<watch::Receiver<RigState>>,
-    rig_tx: web::Data<mpsc::Sender<RigRequest>>,
-) -> Result<HttpResponse, Error> {
-    let enabled = state
-        .get_ref()
-        .borrow()
-        .filter
-        .as_ref()
-        .map(|f| f.wfm_denoise)
-        .unwrap_or(true);
-    send_command(&rig_tx, RigCommand::SetWfmDenoise(!enabled)).await
-}
-
 #[post("/toggle_aprs_decode")]
 pub async fn toggle_aprs_decode(
     state: web::Data<watch::Receiver<RigState>>,
@@ -727,7 +712,6 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(set_fir_taps)
         .service(set_wfm_deemphasis)
         .service(set_wfm_stereo)
-        .service(toggle_wfm_denoise)
         .service(toggle_aprs_decode)
         .service(toggle_cw_decode)
         .service(set_cw_auto)

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

@@ -35,6 +35,5 @@ pub enum RigCommand {
     SetFirTaps(u32),
     SetWfmDeemphasis(u32),
     SetWfmStereo(bool),
-    SetWfmDenoise(bool),
     GetSpectrum,
 }

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

@@ -518,7 +518,6 @@ pub fn command_from_rig_command(cmd: RigCommand) -> Box<dyn RigCommandHandler> {
         | RigCommand::SetFirTaps(_)
         | RigCommand::SetWfmDeemphasis(_)
         | RigCommand::SetWfmStereo(_)
-        | RigCommand::SetWfmDenoise(_)
         | RigCommand::GetSpectrum => Box::new(GetSnapshotCommand),
     }
 }

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

@@ -165,16 +165,6 @@ pub trait RigCat: Rig + Send {
         )))
     }
 
-    fn set_wfm_denoise<'a>(
-        &'a mut self,
-        _enabled: bool,
-    ) -> Pin<Box<dyn Future<Output = DynResult<()>> + Send + 'a>> {
-        Box::pin(std::future::ready(Err(
-            Box::new(response::RigError::not_supported("set_wfm_denoise"))
-                as Box<dyn std::error::Error + Send + Sync>,
-        )))
-    }
-
     fn set_wfm_stereo<'a>(
         &'a mut self,
         _enabled: bool,

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

@@ -273,8 +273,6 @@ pub struct RigFilterState {
     pub wfm_deemphasis_us: u32,
     #[serde(default = "default_wfm_stereo")]
     pub wfm_stereo: bool,
-    #[serde(default = "default_wfm_denoise")]
-    pub wfm_denoise: bool,
     #[serde(default)]
     pub wfm_stereo_detected: bool,
 }
@@ -283,10 +281,6 @@ fn default_wfm_deemphasis_us() -> u32 {
     75
 }
 
-fn default_wfm_denoise() -> bool {
-    true
-}
-
 fn default_wfm_stereo() -> bool {
     true
 }

src/trx-protocol/src/codec.rs

@@ -299,7 +299,6 @@ mod tests {
                 cw_center_hz: 700,
                 wfm_deemphasis_us: 75,
                 wfm_stereo: true,
-                wfm_denoise: true,
                 wfm_stereo_detected: false,
             }),
             ..minimal_snapshot()
@@ -338,7 +337,6 @@ mod tests {
                 cw_center_hz: 700,
                 wfm_deemphasis_us: 50,
                 wfm_stereo: true,
-                wfm_denoise: true,
                 wfm_stereo_detected: true,
             }),
             ..minimal_snapshot()

src/trx-protocol/src/mapping.rs

@@ -52,7 +52,6 @@ pub fn client_command_to_rig(cmd: ClientCommand) -> RigCommand {
             RigCommand::SetWfmDeemphasis(deemphasis_us)
         }
         ClientCommand::SetWfmStereo { enabled } => RigCommand::SetWfmStereo(enabled),
-        ClientCommand::SetWfmDenoise { enabled } => RigCommand::SetWfmDenoise(enabled),
         ClientCommand::GetSpectrum => RigCommand::GetSpectrum,
     }
 }
@@ -98,7 +97,6 @@ pub fn rig_command_to_client(cmd: RigCommand) -> ClientCommand {
             ClientCommand::SetWfmDeemphasis { deemphasis_us }
         }
         RigCommand::SetWfmStereo(enabled) => ClientCommand::SetWfmStereo { enabled },
-        RigCommand::SetWfmDenoise(enabled) => ClientCommand::SetWfmDenoise { enabled },
         RigCommand::GetSpectrum => ClientCommand::GetSpectrum,
     }
 }

src/trx-protocol/src/types.rs

@@ -40,7 +40,6 @@ pub enum ClientCommand {
     SetFirTaps { taps: u32 },
     SetWfmDeemphasis { deemphasis_us: u32 },
     SetWfmStereo { enabled: bool },
-    SetWfmDenoise { enabled: bool },
     GetSpectrum,
 }
 

src/trx-server/src/config.rs

@@ -265,7 +265,7 @@ impl Default for AudioConfig {
             tx_enabled: true,
             device: None,
             sample_rate: 48000,
-            channels: 1,
+            channels: 2,
             frame_duration_ms: 20,
             bitrate_bps: 192000,
         }

src/trx-server/src/rig_task.rs

@@ -472,16 +472,6 @@ async fn process_command(
             let _ = ctx.state_tx.send(ctx.state.clone());
             return snapshot_from(ctx.state);
         }
-        RigCommand::SetWfmDenoise(enabled) => {
-            if let Err(e) = ctx.rig.set_wfm_denoise(enabled).await {
-                return Err(RigError::communication(format!("set_wfm_denoise: {e}")));
-            }
-            if let Some(f) = ctx.state.filter.as_mut() {
-                f.wfm_denoise = enabled;
-            }
-            let _ = ctx.state_tx.send(ctx.state.clone());
-            return snapshot_from(ctx.state);
-        }
         RigCommand::SetCenterFreq(freq) => {
             if let Err(e) = ctx.rig.set_center_freq(freq).await {
                 return Err(RigError::communication(format!("set_center_freq: {e}")));

src/trx-server/trx-backend/trx-backend-soapysdr/src/demod.rs

@@ -297,52 +297,6 @@ impl BiquadNotch {
     }
 }
 
-/// Three-band stereo blend for WFM.
-///
-/// Splits the L-R diff signal into three bands at audio rate and applies
-/// SNR-dependent blending per band.  Weaker pilot → more aggressive noise
-/// reduction at higher frequencies while low frequencies retain more stereo.
-///
-/// | Band      | Frequency   | Blend factor |
-/// |-----------|-------------|--------------|
-/// | Low       | 0 – 2 kHz   | `blend`      |
-/// | Mid       | 2 – 8 kHz   | `blend²`     |
-/// | High      | 8 – 15 kHz  | `blend⁴`     |
-#[derive(Debug, Clone)]
-struct MultibandStereoBlend {
-    /// 2nd-order Butterworth LPF at the low/mid crossover (2 kHz).
-    lo_lp: BiquadLowPass,
-    /// 2nd-order Butterworth LPF at the mid/high crossover (8 kHz).
-    hi_lp: BiquadLowPass,
-}
-
-impl MultibandStereoBlend {
-    fn new(audio_rate: f32) -> Self {
-        // Q = 1/√2 ≈ 0.7071 — maximally flat (Butterworth) 2nd-order response.
-        let q = std::f32::consts::FRAC_1_SQRT_2;
-        Self {
-            lo_lp: BiquadLowPass::new(audio_rate, 2_000.0, q),
-            hi_lp: BiquadLowPass::new(audio_rate, 8_000.0, q),
-        }
-    }
-
-    /// Apply multiband blend to a single diff sample.
-    ///
-    /// `blend` is the pilot SNR estimate in [0, 1] (0 = mono, 1 = full stereo).
-    fn process(&mut self, diff: f32, blend: f32) -> f32 {
-        // Band-split via complementary LPFs.
-        let lo = self.lo_lp.process(diff);        // 0 – 2 kHz
-        let lo_hi = self.hi_lp.process(diff);     // 0 – 8 kHz
-        let mid = lo_hi - lo;                      // 2 – 8 kHz
-        let hi = diff - lo_hi;                     // 8 – 15 kHz
-
-        let blend2 = blend * blend;
-        let blend4 = blend2 * blend2;
-
-        lo * blend + mid * blend2 + hi * blend4
-    }
-}
-
 impl OnePoleLowPass {
     fn new(sample_rate: f32, cutoff_hz: f32) -> Self {
         let sr = sample_rate.max(1.0);
@@ -414,10 +368,6 @@ pub struct WfmStereoDecoder {
     deemph_m: Deemphasis,
     deemph_l: Deemphasis,
     deemph_r: Deemphasis,
-    /// Multiband stereo blending applied at audio rate to the L-R diff channel.
-    diff_denoise: MultibandStereoBlend,
-    /// Whether multiband stereo denoising is active.
-    denoise_enabled: bool,
     /// Smoothed pilot-derived stereo detection strength in [0, 1].
     stereo_detect_level: f32,
     /// Hysteretic pilot-lock result used by the UI.
@@ -453,7 +403,6 @@ impl WfmStereoDecoder {
         output_channels: usize,
         stereo_enabled: bool,
         deemphasis_us: u32,
-        denoise_enabled: bool,
     ) -> Self {
         let composite_rate_f = composite_rate.max(1) as f32;
         let output_phase_inc = audio_rate.max(1) as f64 / composite_rate.max(1) as f64;
@@ -487,8 +436,6 @@ impl WfmStereoDecoder {
             deemph_m: Deemphasis::new(audio_rate.max(1) as f32, deemphasis_us),
             deemph_l: Deemphasis::new(audio_rate.max(1) as f32, deemphasis_us),
             deemph_r: Deemphasis::new(audio_rate.max(1) as f32, deemphasis_us),
-            diff_denoise: MultibandStereoBlend::new(audio_rate.max(1) as f32),
-            denoise_enabled,
             stereo_detect_level: 0.0,
             stereo_detected: false,
             fm_gain: composite_rate_f / (2.0 * 75_000.0),
@@ -601,17 +548,9 @@ impl WfmStereoDecoder {
 
             // --- Deemphasis + DC block + output ---
             if self.output_channels >= 2 && self.stereo_enabled {
-                // Apply multiband or single-band stereo blend at audio rate.
+                let diff = diff_i * blend_i;
-                let diff_denoised = if self.denoise_enabled {
+                let left_corr = (sum_i + diff) * 0.5;
-                    // Multiband: attenuates high-frequency diff more aggressively
+                let right_corr = (sum_i - diff) * 0.5;
-                    // when the pilot is weak, preserving the low-frequency stereo image.
-                    self.diff_denoise.process(diff_i, blend_i)
-                } else {
-                    // Single-band: uniform blend across all frequencies.
-                    diff_i * blend_i
-                };
-                let left_corr = (sum_i + diff_denoised) * 0.5;
-                let right_corr = (sum_i - diff_denoised) * 0.5;
                 let left = self
                     .dc_l
                     .process(self.pilot_notch_l.process(self.deemph_l.process(left_corr)))
@@ -640,10 +579,6 @@ impl WfmStereoDecoder {
         output
     }
 
-    pub fn set_denoise_enabled(&mut self, enabled: bool) {
-        self.denoise_enabled = enabled;
-    }
-
     pub fn set_stereo_enabled(&mut self, enabled: bool) {
         self.stereo_enabled = enabled;
     }
@@ -987,7 +922,6 @@ mod tests {
             2,    // stereo output
             true, // stereo enabled
             50,   // 50 µs deemphasis
-            false, // no denoise — test raw separation
         );
         let output = decoder.process_iq(&iq);
 
@@ -1069,7 +1003,6 @@ mod tests {
             2,
             true,
             50,
-            false,
         );
         let output = decoder.process_iq(&iq);
 

src/trx-server/trx-backend/trx-backend-soapysdr/src/dsp.rs

@@ -311,8 +311,6 @@ pub struct ChannelDsp {
     wfm_deemphasis_us: u32,
     /// Whether WFM stereo decoding is enabled.
     wfm_stereo: bool,
-    /// Whether multiband stereo denoising is enabled for WFM.
-    wfm_denoise: bool,
     /// Decimation factor: `sdr_sample_rate / audio_sample_rate`.
     pub decim_factor: usize,
     /// Number of PCM channels emitted in each frame.
@@ -414,7 +412,6 @@ impl ChannelDsp {
                     self.output_channels,
                     self.wfm_stereo,
                     self.wfm_deemphasis_us,
-                    self.wfm_denoise,
                 ));
             }
         } else {
@@ -436,7 +433,6 @@ impl ChannelDsp {
         audio_bandwidth_hz: u32,
         wfm_deemphasis_us: u32,
         wfm_stereo: bool,
-        wfm_denoise: bool,
         fir_taps: usize,
         pcm_tx: broadcast::Sender<Vec<f32>>,
     ) -> Self {
@@ -482,7 +478,6 @@ impl ChannelDsp {
             fir_taps: taps,
             wfm_deemphasis_us,
             wfm_stereo,
-            wfm_denoise,
             decim_factor,
             output_channels,
             frame_buf: Vec::with_capacity(frame_size + output_channels),
@@ -504,7 +499,6 @@ impl ChannelDsp {
                     output_channels,
                     wfm_stereo,
                     wfm_deemphasis_us,
-                    wfm_denoise,
                 ))
             } else {
                 None
@@ -557,13 +551,6 @@ impl ChannelDsp {
         }
     }
 
-    pub fn set_wfm_denoise(&mut self, enabled: bool) {
-        self.wfm_denoise = enabled;
-        if let Some(decoder) = &mut self.wfm_decoder {
-            decoder.set_denoise_enabled(enabled);
-        }
-    }
-
     pub fn rds_data(&self) -> Option<RdsData> {
         self.wfm_decoder.as_ref().and_then(WfmStereoDecoder::rds_data)
     }
@@ -724,7 +711,6 @@ impl SdrPipeline {
         frame_duration_ms: u16,
         wfm_deemphasis_us: u32,
         wfm_stereo: bool,
-        wfm_denoise: bool,
         channels: &[(f64, RigMode, u32, usize)],
     ) -> Self {
         const IQ_BROADCAST_CAPACITY: usize = 64;
@@ -747,7 +733,6 @@ impl SdrPipeline {
                 audio_bandwidth_hz,
                 wfm_deemphasis_us,
                 wfm_stereo,
-                wfm_denoise,
                 fir_taps,
                 pcm_tx.clone(),
             );

src/trx-server/trx-backend/trx-backend-soapysdr/src/lib.rs

@@ -41,8 +41,6 @@ pub struct SoapySdrRig {
     wfm_deemphasis_us: u32,
     /// Whether WFM stereo decode is enabled.
     wfm_stereo: bool,
-    /// Whether multiband WFM stereo denoising is enabled.
-    wfm_denoise: bool,
 }
 
 impl SoapySdrRig {
@@ -120,7 +118,6 @@ impl SoapySdrRig {
             frame_duration_ms,
             wfm_deemphasis_us,
             true, // wfm_stereo: enabled by default
-            true, // wfm_denoise: enabled by default
             channels,
         );
 
@@ -189,7 +186,6 @@ impl SoapySdrRig {
             retune_cmd,
             wfm_deemphasis_us,
             wfm_stereo: true,
-            wfm_denoise: true,
         })
     }
 
@@ -481,19 +477,6 @@ impl RigCat for SoapySdrRig {
         })
     }
 
-    fn set_wfm_denoise<'a>(
-        &'a mut self,
-        enabled: bool,
-    ) -> Pin<Box<dyn std::future::Future<Output = DynResult<()>> + Send + 'a>> {
-        Box::pin(async move {
-            self.wfm_denoise = enabled;
-            if let Some(dsp_arc) = self.pipeline.channel_dsps.get(self.primary_channel_idx) {
-                dsp_arc.lock().unwrap().set_wfm_denoise(enabled);
-            }
-            Ok(())
-        })
-    }
-
     fn filter_state(&self) -> Option<RigFilterState> {
         let wfm_stereo_detected = self
             .pipeline
@@ -507,7 +490,6 @@ impl RigCat for SoapySdrRig {
             cw_center_hz: 700,
             wfm_deemphasis_us: self.wfm_deemphasis_us,
             wfm_stereo: self.wfm_stereo,
-            wfm_denoise: self.wfm_denoise,
             wfm_stereo_detected,
         })
     }