Correct goniometer transport and correlation meter

TODO.md

@@ -126,17 +126,18 @@ Diese vorhandenen Funktionen sind nicht automatisch messtechnisch korrekt. Die f
 
 - [ ] **14. Goniometer-Datenweg und Persistenz optimieren**
   - **Soll:** Aktuelle XY-Daten erscheinen im nächsten möglichen Bildschirmframe; Fast/Medium/Slow-Persistenz wirkt wie das RTW-Instrument.
-  - **Ist:** M/S-Darstellung, Gain, AGC, Linien/Punkte und eine 300-ms-Spur sind vorhanden.
-  - **Datenweg erledigt:** XY-Punkte werden mit begrenzter Rate über den eigenen Binärstrom übertragen; JSON-Kopien und unbeschränkte Warteschlangen entfallen.
-  - **Noch offen:** RTW-Persistenzmodi sind nicht verbindlich abgeglichen.
-  - **Aufgabe:** Fast/Medium/Slow-Persistenz am Referenzgerät abstimmen und die vorhandene Ringpufferdarstellung darauf kalibrieren.
+  - **Ist:** M/S-Darstellung, manueller Gain, AGC, Linien/Punkte sowie reproduzierbare Fast-/Medium-/Slow- und freie Phoenix-Persistenz sind vorhanden.
+  - **Datenweg erledigt:** Es werden nur die seit der letzten Ausgabe neu eingegangenen Samplepaare mit im Mittel exakt 60 Hz über den eigenen Binärstrom übertragen. Die Punktzahl begrenzt bereits den Transport; der Browser erfindet keine interpolierten XY-Samples. JSON-Kopien und unbeschränkte Warteschlangen entfallen.
+  - **Darstellung erledigt:** Die Nachleuchtspuren sind auf 48 Zustände begrenzt und verwenden freigegebene `Float32Array`-Puffer erneut. Kosmetische Bézier-Verformung der Messspur ist im RTW-Profil deaktiviert. AGC wird nur bei einem neuen XY-Paket weitergerechnet; das Silence-Gate verwendet das periodengrößenunabhängige XY-Fenster.
+  - **Geprüft:** Automatische Tests prüfen 60-Hz-Taktung bei 44,1/48/96 kHz und unterschiedlichen Periodengrößen, Punktbegrenzung, Endpunkte, Persistenzprofile und Pufferbegrenzung.
+  - **Noch offen:** Die gewählten 50/150/300 ms müssen visuell am echten RTW-Gerät abgeglichen werden; deshalb bleibt der Gesamtpunkt offen.
   - **Abnahme:** Geringe Reaktionslatenz ohne unnötige Allokationen, bei vergleichbarem visuellen Nachleuchten.
 
 - [ ] **15. Korrelation vollständig am RTW-Verhalten prüfen**
   - **Soll:** Bereich -1 bis +1, passende Farben, wählbare Ansprechzeiten von 1,0 s und 2,5 s sowie Negative-Peak-Memory.
-  - **Ist:** Korrelations- und Phasendarstellungen sind grundsätzlich vorhanden.
-  - **Ungeklärt:** Zeitkonstanten, Speicherverhalten und Genauigkeit sind nicht systematisch gegen das PortaMonitor geprüft.
-  - **Aufgabe:** Testsignale für +1, 0 und -1 sowie gleitende Phasenlagen verwenden; Memory und Reset ergänzen beziehungsweise validieren.
+  - **Ist:** Die Korrelation wird samplekontinuierlich im Audiokern aus gleich integrierten L²-, R²- und L·R-Leistungen berechnet. 1,0 s und 2,5 s sind wählbar; der Browser zeigt den fertigen Wert ohne zweite bildratenabhängige Glättung. Negative-Peak-Memory, Marker und manueller Reset sind implementiert.
+  - **Geprüft:** Automatische Tests prüfen +1, 0 und -1, Stille, einseitiges Signal, beide Ansprechzeiten und den Memory-Reset.
+  - **Noch offen:** Dynamische Phasenlagen und das exakte Zeit-/Memory-Verhalten müssen am PortaMonitor verglichen werden; deshalb bleibt der Gesamtpunkt offen.
   - **Abnahme:** Statische und dynamische Testsignale stimmen innerhalb der festgelegten Toleranz mit der Referenz überein.
 
 ## Priorität 4 - Nachweis und dauerhafte Absicherung
@@ -158,7 +159,7 @@ Diese vorhandenen Funktionen sind nicht automatisch messtechnisch korrekt. Die f
 - [ ] **18. Automatisierte DSP- und Darstellungsregressionstests aufbauen**
   - **Soll:** Keine Änderung kann unbemerkt Pegel, Frequenzgang, Ballistik, Latenz oder RTW-Darstellung verschlechtern.
   - **Ist:** DIN-/EBU-PPM, Spektrogramm-Zeitbasis und Langlauf, Worker-Verhalten sowie die Binärprotokolle sind automatisiert abgesichert. Servertests prüfen außerdem das Zusammenführen der Waveform-Hüllkurve und die Trennung großer Nutzdaten vom JSON-Messstrom.
-  - **Noch offen:** Der RTA besitzt nun Tests für alle Bandmitten und -kanten, Nachbarbandunterdrückung, Zeitbereich, A/C/Z, mehrere Sampleraten und blockgrößenunabhängige Integration. True Peak, VU/RMS, Korrelation, reale Periodenvariation und End-to-End-Latenz besitzen noch keine vollständige automatische Regression. Deshalb bleibt dieser Gesamtpunkt offen.
+  - **Noch offen:** RTA und Korrelation besitzen nun DSP-Tests; der Goniometerweg prüft mehrere Sampleraten, Periodengrößen, Punktreduktion und Persistenzprofile. True Peak, VU/RMS, dynamische Referenzvergleiche und End-to-End-Latenz besitzen noch keine vollständige automatische Regression. Deshalb bleibt dieser Gesamtpunkt offen.
   - **Aufgabe:** Einzeltöne aller 31 Bänder, Sweeps, Weiß-/Rosarauschen, Pegelsprünge, Tonbursts, Phasen-/Korrelationssignale und Intersample-Peaks testen. Sampleraten, Perioden und Blockgrenzen variieren. RTW-Screenshots und Messprotokolle als Referenz verwenden, soweit rechtlich möglich.
   - **Abnahme:** Automatischer Bericht mit Erwartungswerten und Toleranzen für jede Messfunktion.
 

scripts/test_goniometer.mjs

@@ -0,0 +1,31 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import vm from 'node:vm';
+
+const source = fs.readFileSync(new URL('../www/views/goniometer_rtw.js', import.meta.url), 'utf8');
+const functionSource = source.match(/export function resolveGoniometerPersistenceMs[\s\S]*?\n\}/)?.[0];
+assert.ok(functionSource, 'persistence resolver must remain testable');
+const context = vm.createContext({ Number, String, Math });
+vm.runInContext(functionSource.replace('export function', 'function'), context);
+
+assert.equal(context.resolveGoniometerPersistenceMs({ GONIO_PERSISTENCE_MODE: 'fast' }), 50);
+assert.equal(context.resolveGoniometerPersistenceMs({ GONIO_PERSISTENCE_MODE: 'medium' }), 150);
+assert.equal(context.resolveGoniometerPersistenceMs({ GONIO_PERSISTENCE_MODE: 'slow' }), 300);
+assert.equal(context.resolveGoniometerPersistenceMs({
+  GONIO_PERSISTENCE_MODE: 'custom',
+  GONIO_LINE_FADE_MS: 470,
+}), 470);
+assert.equal(context.resolveGoniometerPersistenceMs({
+  GONIO_PERSISTENCE_MODE: 'custom',
+  GONIO_LINE_FADE_MS: 900,
+}), 600);
+
+assert.match(source, /Math\.min\(targetPoints, total, MAX_TRACE_POINTS\)/,
+  'drawing must not upsample invented XY points');
+assert.match(source, /while \(trails\.length >= MAX_TRAIL_FRAMES\)/,
+  'trail history must remain bounded');
+assert.match(source, /pool\.pop\(\)/, 'trail buffers must be reused');
+assert.doesNotMatch(source, /utils\.correlation\(/,
+  'browser must not recalculate or smooth backend correlation');
+
+console.log('goniometer regression tests passed');

scripts/test_rta_profile.mjs

@@ -19,12 +19,18 @@ const forced = context.buildRtaRuntimeConfig({
   RTA_BPO_MODE: '1_12',
   RTA_FREQ_RANGE: 'lf',
   RTA_IIR_ORDER: 2,
+  CORR_RESPONSE_S: 2.5,
+  CORR_RESET_TOKEN: 7,
+  XY_POINTS: 256,
 });
 assert.equal(forced.engine, 'iir');
 assert.equal(forced.bpo, '1_3');
 assert.equal(forced.freqRange, 'norm');
 assert.equal(forced.order, 6);
 assert.equal(forced.rtwCenters.length, 31);
+assert.equal(forced.correlationResponseS, 2.5);
+assert.equal(forced.correlationResetToken, 7);
+assert.equal(forced.xyPoints, 256);
 
 const extension = context.buildRtaRuntimeConfig({
   RTA_BAR_LAYOUT: 'iec',

src/audio.rs

@@ -11,11 +11,13 @@ use std::{
 
 use tracing::warn;
 
-#[cfg(target_os = "linux")]
-use crate::model::{RtaFrame, SpectroFrame, WaveEnvFrame};
 #[cfg(target_os = "linux")]
 use crate::correlation::CorrelationMeter;
 #[cfg(target_os = "linux")]
+use crate::goniometer::{selected_sample_indices, GoniometerClock};
+#[cfg(target_os = "linux")]
+use crate::model::{RtaFrame, SpectroFrame, WaveEnvFrame};
+#[cfg(target_os = "linux")]
 use crate::ppm::{PpmDetector, PpmStandard};
 #[cfg(target_os = "linux")]
 use crate::rta::{
@@ -481,7 +483,7 @@ struct PpmState {
     correlation: CorrelationMeter,
     xy_pending_l: Vec<f32>,
     xy_pending_r: Vec<f32>,
-    xy_emit_phase: u64,
+    xy_clock: GoniometerClock,
 }
 
 #[cfg(target_os = "linux")]
@@ -513,7 +515,7 @@ impl Default for PpmState {
             correlation: CorrelationMeter::new(48_000, 1.0, 0),
             xy_pending_l: Vec::with_capacity(1024),
             xy_pending_r: Vec::with_capacity(1024),
-            xy_emit_phase: 0,
+            xy_clock: GoniometerClock::default(),
         }
     }
 }
@@ -1153,8 +1155,7 @@ fn take_goniometer_samples(state: &mut PpmState, target_points: usize) -> (Vec<f
     } else {
         // Preserve chronological sample pairs while reducing transport to the
         // selected display density. Endpoints are always retained.
-        for index in 0..count {
-            let source = index * (available - 1) / (count - 1);
+        for source in selected_sample_indices(available, count) {
             left.push(state.xy_pending_l[source]);
             right.push(state.xy_pending_r[source]);
         }
@@ -1284,11 +1285,11 @@ fn build_meter_frame(
     let ppm_ebu_l = dbfs(ppm_ebu_amp_l);
     let ppm_ebu_r = dbfs(ppm_ebu_amp_r);
     let wave_env = wave_env_flush(&mut ppm_state.wave_env);
-    ppm_state.xy_emit_phase = ppm_state.xy_emit_phase.saturating_add(
-        (frames as u64).saturating_mul(XY_TARGET_UPDATES_PER_SECOND),
-    );
-    let (xy_l, xy_r) = if ppm_state.xy_emit_phase >= u64::from(sample_rate.max(1)) {
-        ppm_state.xy_emit_phase %= u64::from(sample_rate.max(1));
+    let (xy_l, xy_r) =
+        if ppm_state
+            .xy_clock
+            .advance(frames, sample_rate, XY_TARGET_UPDATES_PER_SECOND as u32)
+        {
             take_goniometer_samples(ppm_state, rta_config.xy_points as usize)
         } else {
             (Vec::new(), Vec::new())

src/correlation.rs

@@ -27,7 +27,7 @@ impl CorrelationMeter {
             power_r: 0.0,
             cross_power: 0.0,
             value: 0.0,
-            negative_peak: 1.0,
+            negative_peak: 0.0,
             reset_token,
         };
         meter.configure(sample_rate, response_seconds, reset_token);
@@ -40,12 +40,12 @@ impl CorrelationMeter {
         if self.sample_rate != sample_rate || self.response_seconds != response_seconds {
             self.sample_rate = sample_rate;
             self.response_seconds = response_seconds;
-            self.alpha = 1.0
-                - (-1.0 / (f64::from(sample_rate) * f64::from(response_seconds))).exp();
+            self.alpha =
+                1.0 - (-1.0 / (f64::from(sample_rate) * f64::from(response_seconds))).exp();
         }
         if self.reset_token != reset_token {
             self.reset_token = reset_token;
-            self.negative_peak = 1.0;
+            self.negative_peak = 0.0;
         }
     }
 
@@ -106,13 +106,21 @@ mod tests {
     fn detects_positive_negative_and_quadrature_signals() {
         let sample_rate = 48_000;
         let phase_step = 2.0 * std::f32::consts::PI * 1_000.0 / sample_rate as f32;
-        for (phase, expected) in [(0.0, 1.0), (std::f32::consts::PI, -1.0), (std::f32::consts::FRAC_PI_2, 0.0)] {
+        for (phase, expected) in [
+            (0.0, 1.0),
+            (std::f32::consts::PI, -1.0),
+            (std::f32::consts::FRAC_PI_2, 0.0),
+        ] {
             let mut meter = CorrelationMeter::new(sample_rate, 1.0, 0);
             run_signal(&mut meter, 5, |index| {
                 let angle = phase_step * index as f32;
                 (angle.sin(), (angle + phase).sin())
             });
-            assert!((meter.value() - expected).abs() < 0.002, "phase {phase}: {}", meter.value());
+            assert!(
+                (meter.value() - expected).abs() < 0.002,
+                "phase {phase}: {}",
+                meter.value()
+            );
         }
     }
 
@@ -134,7 +142,7 @@ mod tests {
         });
         assert!(fast.negative_peak() < -0.7);
         fast.configure(sample_rate, 1.0, 1);
-        assert_eq!(fast.negative_peak(), 1.0);
+        assert_eq!(fast.negative_peak(), 0.0);
     }
 
     #[test]
@@ -142,6 +150,7 @@ mod tests {
         let mut meter = CorrelationMeter::new(48_000, 1.0, 0);
         run_signal(&mut meter, 2, |_| (0.0, 0.0));
         assert_eq!(meter.value(), 0.0);
+        assert_eq!(meter.negative_peak(), 0.0);
         run_signal(&mut meter, 2, |index| {
             let sample = if index & 1 == 0 { 0.5 } else { -0.5 };
             (sample, 0.0)

src/goniometer.rs

@@ -0,0 +1,70 @@
+//! Timing and sample-selection helpers for the realtime goniometer stream.
+
+#[derive(Clone, Debug, Default)]
+pub struct GoniometerClock {
+    phase: u64,
+}
+
+impl GoniometerClock {
+    /// Returns true at the first capture boundary after the next display tick.
+    /// The fractional phase is retained, so the average rate is independent
+    /// of ALSA period size.
+    pub fn advance(&mut self, frames: usize, sample_rate: u32, updates_per_second: u32) -> bool {
+        let sample_rate = u64::from(sample_rate.max(1));
+        self.phase = self
+            .phase
+            .saturating_add((frames as u64).saturating_mul(u64::from(updates_per_second.max(1))));
+        if self.phase < sample_rate {
+            return false;
+        }
+        self.phase %= sample_rate;
+        true
+    }
+}
+
+pub fn selected_sample_indices(available: usize, requested: usize) -> Vec<usize> {
+    if available == 0 || requested == 0 {
+        return Vec::new();
+    }
+    let count = available.min(requested.max(2));
+    if count >= available {
+        return (0..available).collect();
+    }
+    (0..count)
+        .map(|index| index * (available - 1) / (count - 1))
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn update_rate_is_independent_of_capture_period() {
+        for (sample_rate, period) in [(44_100, 128), (48_000, 128), (48_000, 192), (96_000, 512)] {
+            let mut clock = GoniometerClock::default();
+            let mut emissions = 0usize;
+            let mut processed = 0usize;
+            let target = sample_rate as usize * 10;
+            while processed < target {
+                let frames = period.min(target - processed);
+                emissions += usize::from(clock.advance(frames, sample_rate, 60));
+                processed += frames;
+            }
+            assert!(
+                (599..=600).contains(&emissions),
+                "{sample_rate}/{period}: {emissions}"
+            );
+        }
+    }
+
+    #[test]
+    fn selection_never_upsamples_and_keeps_endpoints() {
+        assert_eq!(selected_sample_indices(3, 1024), vec![0, 1, 2]);
+        let indices = selected_sample_indices(800, 128);
+        assert_eq!(indices.len(), 128);
+        assert_eq!(indices[0], 0);
+        assert_eq!(indices[127], 799);
+        assert!(indices.windows(2).all(|pair| pair[0] < pair[1]));
+    }
+}

src/main.rs

@@ -1,6 +1,7 @@
 mod audio;
 mod config;
 mod correlation;
+mod goniometer;
 mod model;
 mod ppm;
 mod routes;

www/core/audio.js

@@ -351,6 +351,7 @@ function applyVisualsBuffer(env, buffer) {
     env.audio.xyL = left;
     env.audio.xyR = right;
     env.audio.xySeq = seq;
+    env.audio.xyLastSampleTs = performance.now();
   }
   if (wave) updateWaveformEnvelopeStore(env.audio, wave);
   env.audio.phoenixVisualsSeq = seq;
@@ -409,6 +410,7 @@ async function applyIncomingAudioPacket(env, packet, CONFIG, sampleTs = performa
     env.audio.xyL = d.xyL;
     env.audio.xyR = d.xyR;
     env.audio.xySeq = Number.isFinite(d.seq) ? d.seq : (env.audio.xySeq || 0);
+    env.audio.xyLastSampleTs = sampleTs;
   }
   if (typeof d.correlation === 'number') env.audio.correlation = d.correlation;
   if (typeof d.correlationNegativePeak === 'number') {

www/core/config.js

@@ -934,6 +934,13 @@ function loadConfig(opts = {}) {
       const fallback = Number.isFinite(CONFIG.GONIO_DISPLAY_GAIN_DB) ? CONFIG.GONIO_DISPLAY_GAIN_DB : 0;
       CONFIG.GONIO_MANUAL_GAIN_DB = Math.max(-35, Math.min(35, Math.round(fallback / 5) * 5));
     }
+    CONFIG.CORR_RESPONSE_S = Number(CONFIG.CORR_RESPONSE_S) >= 1.75 ? 2.5 : 1.0;
+    CONFIG.CORR_RESET_TOKEN = Math.max(0, Math.floor(Number(CONFIG.CORR_RESET_TOKEN) || 0));
+    const persistenceMode = String(CONFIG.GONIO_PERSISTENCE_MODE || 'fast').toLowerCase();
+    CONFIG.GONIO_PERSISTENCE_MODE = ['fast', 'medium', 'slow', 'custom'].includes(persistenceMode)
+      ? persistenceMode
+      : 'fast';
+    CONFIG.GONIO_LINE_FADE_MS = Math.max(0, Math.min(600, Number(CONFIG.GONIO_LINE_FADE_MS) || 0));
   } catch (e) {
     console.warn('Config load error:', e);
   }

www/index.html

@@ -507,23 +507,23 @@
               <input id="opt_xySilenceGate" type="checkbox" checked>
               Silence-Gate aktivieren (RMS-basiert)
             </label>
-            <small>Gatet Goniometer &amp; Korrelation bei Pegeln unterhalb der Schwelle</small>
+            <small>Blendet nur die Goniometer-Spur bei Stille aus; die Korrelation wird unabhängig kontinuierlich gemessen.</small>
           </div>
           <div class="opt">
             <label>Silence-Threshold [dBFS RMS]</label>
             <input id="opt_xySilenceThr" type="number" min="-90" max="-40" step="1" style="width:120px">
             <small>Default: -75 dBFS RMS (Mono)</small>
           </div>
-          <div class="opt"><label>Korrelation Glättung</label>
-            <input id="opt_corrSmooth" type="range" min="0.5" max="0.98" step="0.01"><span id="val_corrSmooth"></span>
-            <small>Glättet die Korrelation für ruhigere Anzeige</small>
+          <div class="opt"><label>Korrelation Ansprechzeit</label>
+            <select id="opt_corrResponse">
+              <option value="1">1,0 s</option>
+              <option value="2.5">2,5 s</option>
+            </select>
+            <small>Kontinuierliche DSP-Integration; unabhängig von Bildrate und ALSA-Periode.</small>
           </div>
           <div class="opt">
-            <label class="row" style="align-items:center;gap:8px">
-              <input id="opt_corrZeroOnSilence" type="checkbox">
-              Sofortige Nullstellung wenn kein Pegel
-            </label>
-            <small>Setzt den Korrelations‑Würfel bei Stille sofort auf 0 (ohne Hold/Drift).</small>
+            <button id="opt_corrResetPeak" type="button">Negativspitze zurücksetzen</button>
+            <small>Setzt den Negative-Peak-Memory auf 0 zurück; der rote Marker verschwindet.</small>
           </div>
           <div class="opt"><label>Goniometer Display Gain (dB)</label>
             <input id="opt_goniGain" type="range" min="-35" max="35" step="5"><span id="val_goniGain"></span>
@@ -536,9 +536,18 @@
             <input id="opt_goniGap" type="range" min="2" max="24" step="1"><span id="val_goniGap"></span>
             <small>Abstand zwischen den XY-Meter-Slots</small>
           </div>
-          <div class="opt"><label>Goniometer Fade-Out</label>
+          <div class="opt"><label>Goniometer-Persistenz</label>
+            <select id="opt_goniPersistence">
+              <option value="fast">Fast (50 ms)</option>
+              <option value="medium">Medium (150 ms)</option>
+              <option value="slow">Slow (300 ms)</option>
+              <option value="custom">Phoenix – frei</option>
+            </select>
+            <small>Fast/Medium/Slow sind reproduzierbare Profile; die endgültige RTW-Abstimmung erfolgt am Referenzgerät.</small>
+          </div>
+          <div class="opt"><label>Freies Fade-Out</label>
             <input id="opt_goniFade" type="range" min="0" max="600" step="10"><span id="val_goniFade"></span>
-            <small>Nachleuchten der Spur (ms)</small>
+            <small>Wird beim Verschieben automatisch als Phoenix-Profil aktiviert.</small>
           </div>
         </div>
       </details>

www/ui/options.js

@@ -270,8 +270,7 @@ function syncUI() {
     ['opt_rmsColNorm', CONFIG.RMS_COLOR_NORMAL],
     ['opt_rmsColWarn', CONFIG.RMS_COLOR_WARN],
 
-    ['opt_corrSmooth', CONFIG.CORR_SMOOTH, 'val_corrSmooth', (v)=>Number(v).toFixed(2)],
-    ['opt_corrZeroOnSilence', CONFIG.CORR_ZERO_ON_SILENCE, null, null, 'checkbox'],
+    ['opt_corrResponse', String(Number(CONFIG.CORR_RESPONSE_S) >= 1.75 ? 2.5 : 1)],
     ['opt_xyPoints', String(CONFIG.XY_POINTS)],
     ['opt_xyStyle', CONFIG.XY_STYLE],
     ['opt_xySilenceGate', CONFIG.XY_SILENCE_GATE_ENABLED, null, null, 'checkbox'],
@@ -316,6 +315,7 @@ function syncUI() {
     ['opt_phaseTrail', CONFIG.PHASE_TRAIL_ENABLED, null, null, 'checkbox'],
     ['opt_goniGap', CONFIG.GONI_METER_GAP, 'val_goniGap', (v)=>`${v} px`],
     ['opt_goniFade', CONFIG.GONIO_LINE_FADE_MS, 'val_goniFade', (v)=>`${Math.round(v)} ms`],
+    ['opt_goniPersistence', CONFIG.GONIO_PERSISTENCE_MODE || 'fast'],
     ['opt_panelDividers', CONFIG.PANEL_DIVIDERS_ENABLED, null, null, 'checkbox'],
     ['opt_lufsRedThr', CONFIG.LUFS_RED_START],
     ['opt_lufsYellowThr', CONFIG.LUFS_YELLOW_START],
@@ -916,11 +916,17 @@ function wireHandlers(env) {
     notifyPhoenixGlobalConfig();
   });
 
-  h('opt_corrSmooth', v => CONFIG.CORR_SMOOTH = clamp(+v, 0.5, 0.98), 'val_corrSmooth', v=>Number(v).toFixed(2));
-  h('opt_corrZeroOnSilence', v => {
-    CONFIG.CORR_ZERO_ON_SILENCE = !!v;
-    return CONFIG.CORR_ZERO_ON_SILENCE;
-  }, null, null, true);
+  h('opt_corrResponse', v => {
+    CONFIG.CORR_RESPONSE_S = Number(v) >= 1.75 ? 2.5 : 1.0;
+    try { env?.notifyRtaConfig?.(); } catch (_) {}
+    return String(CONFIG.CORR_RESPONSE_S);
+  });
+  const corrResetPeak = E('opt_corrResetPeak');
+  if (corrResetPeak) corrResetPeak.onclick = () => {
+    CONFIG.CORR_RESET_TOKEN = Math.max(0, Math.floor(Number(CONFIG.CORR_RESET_TOKEN) || 0)) + 1;
+    saveConfig();
+    try { env?.notifyRtaConfig?.(); } catch (_) {}
+  };
   h('opt_xyPoints', v => {
     const raw = Number(v);
     CONFIG.XY_POINTS = [128, 256, 512, 1024, 2048].includes(raw)
@@ -1047,7 +1053,17 @@ function wireHandlers(env) {
     notifyPhoenixGlobalConfig();
   }, null, null, true);
   h('opt_goniGap', v => CONFIG.GONI_METER_GAP = clamp(+v, 2, 24), 'val_goniGap', v=>`${v} px`);
-  h('opt_goniFade', v => { CONFIG.GONIO_LINE_FADE_MS = clamp(+v, 0, 600); }, 'val_goniFade', v=>`${Math.round(v)} ms`);
+  h('opt_goniPersistence', v => {
+    const mode = String(v).toLowerCase();
+    CONFIG.GONIO_PERSISTENCE_MODE = ['fast', 'medium', 'slow', 'custom'].includes(mode) ? mode : 'fast';
+    return CONFIG.GONIO_PERSISTENCE_MODE;
+  });
+  h('opt_goniFade', v => {
+    CONFIG.GONIO_LINE_FADE_MS = clamp(+v, 0, 600);
+    CONFIG.GONIO_PERSISTENCE_MODE = 'custom';
+    const persistence = E('opt_goniPersistence');
+    if (persistence) persistence.value = 'custom';
+  }, 'val_goniFade', v=>`${Math.round(v)} ms`);
   h('opt_panelDividers', v => {
     CONFIG.PANEL_DIVIDERS_ENABLED = !!v;
     return CONFIG.PANEL_DIVIDERS_ENABLED;

www/views/goniometer_rtw.js

@@ -41,6 +41,7 @@ export function init() {
     agcEnv: 1e-3,
     agcGainDb: 0,
     agcLastTs: 0,
+    agcLastXySeq: 0,
     traceBuffer: new Float32Array(0),
     lineTrails: [],
     trailPool: [],
@@ -51,7 +52,12 @@ export function init() {
 }
 
 export function resize() {}
-export function destroy() {}
+export function destroy(state) {
+  if (!state) return;
+  clearTrails(state);
+  state.trailPool.length = 0;
+  state.traceBuffer = new Float32Array(0);
+}
 
 export async function render(env, state) {
   const { ctx: g, rect, config: CONFIG, audio, utils, meters } = env;
@@ -68,12 +74,14 @@ export async function render(env, state) {
   const layout = computeGoniometerLayout(rect, CONFIG, slots.length, topInset);
   const settings = resolveScopeSettings(CONFIG);
   const style = CONFIG.XY_STYLE === 'points' ? 'points' : 'lines';
-  const gate = resolveSilenceGate(env, CONFIG, state);
 
   drawStaticLayer(g, state, rect, layout, CONFIG, slots.length);
 
   const xyData = extractXYData(audio);
-  const lastSampleTs = Number.isFinite(env?.audio?.lastSampleTs) ? Number(env.audio.lastSampleTs) : 0;
+  const gate = resolveSilenceGate(CONFIG, state, xyData);
+  const lastSampleTs = Number.isFinite(env?.audio?.xyLastSampleTs)
+    ? Number(env.audio.xyLastSampleTs)
+    : 0;
   const audioAgeMs = lastSampleTs ? (frameNow - lastSampleTs) : Infinity;
   const audioFresh = Number.isFinite(audioAgeMs) && audioAgeMs >= 0 && audioAgeMs <= 250;
   const xyReady = xyData.ready && audioFresh;
@@ -396,6 +404,7 @@ function extractXYData(audio) {
     ready,
     xyL,
     xyR,
+    seq: Number(audio?.xySeq) || 0,
     length: ready ? Math.min(xyL.length, xyR.length) : 0,
   };
 }
@@ -403,7 +412,7 @@ function extractXYData(audio) {
 function resolveScopeSettings(CONFIG) {
   let gainDb = Number.isFinite(CONFIG?.GONIO_DISPLAY_GAIN_DB) ? CONFIG.GONIO_DISPLAY_GAIN_DB : 0;
   gainDb = Math.max(GONIO_GAIN_MIN_DB, Math.min(GONIO_GAIN_MAX_DB, Math.round(gainDb / 5) * 5));
-  const lineFadeMs = Number.isFinite(CONFIG?.GONIO_LINE_FADE_MS) ? CONFIG.GONIO_LINE_FADE_MS : 300;
+  const lineFadeMs = resolveGoniometerPersistenceMs(CONFIG);
   const rtwClassic = true;
   return {
     gainDb,
@@ -417,16 +426,37 @@ function resolveScopeSettings(CONFIG) {
     pointBaseAlpha: rtwClassic ? 0.14 : 0.16,
     pointBoostAlpha: rtwClassic ? 0.34 : 0.36,
     pointSize: rtwClassic ? 1.4 : 2.2,
-    curveSmoothing: rtwClassic,
+    // Do not bend the measured M/S sample path with cosmetic Bézier curves.
+    curveSmoothing: false,
   };
 }
 
-function resolveSilenceGate(env, CONFIG, state) {
+export function resolveGoniometerPersistenceMs(CONFIG = {}) {
+  const mode = String(CONFIG.GONIO_PERSISTENCE_MODE || 'fast').toLowerCase();
+  if (mode === 'medium') return 150;
+  if (mode === 'slow') return 300;
+  if (mode === 'custom') {
+    const custom = Number(CONFIG.GONIO_LINE_FADE_MS);
+    return Number.isFinite(custom) ? Math.max(0, Math.min(600, custom)) : 50;
+  }
+  return 50;
+}
+
+function resolveSilenceGate(CONFIG, state, xyData) {
   const enabled = CONFIG?.XY_SILENCE_GATE_ENABLED !== false;
   const threshold = Number.isFinite(CONFIG?.XY_SILENCE_THRESHOLD_RMS_DBFS)
     ? CONFIG.XY_SILENCE_THRESHOLD_RMS_DBFS
     : CORR_SILENCE_THRESHOLD_DEFAULT;
-  const rmsMono = Number.isFinite(env.audio?.rmsDb?.mono) ? env.audio.rmsDb.mono : -120;
+  let power = 0;
+  if (xyData?.ready && xyData.length > 0) {
+    for (let index = 0; index < xyData.length; index++) {
+      const left = Number(xyData.xyL[index]) || 0;
+      const right = Number(xyData.xyR[index]) || 0;
+      power += left * left + right * right;
+    }
+    power /= 2 * xyData.length;
+  }
+  const rmsMono = power > 1e-12 ? 10 * Math.log10(power) : -120;
   const targetActive = enabled ? (rmsMono >= threshold) : true;
   const now = getNow();
   const dt = state.gateLastTs ? Math.max(0, (now - state.gateLastTs) / 1000) : 0;
@@ -450,7 +480,8 @@ function buildTrace(state, xyData, scope, scale, CONFIG) {
   if (targetPoints <= 1 || total <= 1) {
     return { buffer: null, count: 0 };
   }
-  const sampleCount = Math.max(2, Math.min(targetPoints, MAX_TRACE_POINTS));
+  // The browser may reduce density but must never invent interpolated samples.
+  const sampleCount = Math.max(2, Math.min(targetPoints, total, MAX_TRACE_POINTS));
   if (sampleCount <= 1) {
     return { buffer: null, count: 0 };
   }
@@ -497,7 +528,7 @@ function renderTrace(g, state, trace, scope, style, xyReady, settings) {
 
   if (style === 'lines') {
     if (lineFadeMs <= 0) {
-      trails.length = 0;
+      clearTrails(state);
       if (hasTrace && trace.count > 1) {
         drawImmediateLine(g, trace, scope, settings);
       } else if (!xyReady) {
@@ -505,14 +536,14 @@ function renderTrace(g, state, trace, scope, style, xyReady, settings) {
       }
     } else {
       if (hasTrace && trace.count > 1) {
-        addLineTrail(trails, trace, now);
+        addLineTrail(state, trace, now);
       }
-      const rendered = drawLineTrails(g, trails, scope, now, lineFadeMs, settings);
+      const rendered = drawLineTrails(g, trails, state.trailPool, scope, now, lineFadeMs, settings);
       if (!rendered && !xyReady) drawIdleMessage(g, scope);
     }
   } else {
     if (lineFadeMs <= 0) {
-      trails.length = 0;
+      clearTrails(state);
       if (hasTrace) {
         drawPointTrace(g, trace, scope, settings);
       } else if (!xyReady) {
@@ -520,9 +551,9 @@ function renderTrace(g, state, trace, scope, style, xyReady, settings) {
       }
     } else {
       if (hasTrace && trace.count > 0) {
-        addLineTrail(trails, trace, now);
+        addLineTrail(state, trace, now);
       }
-      const rendered = drawPointTrails(g, trails, scope, now, lineFadeMs, settings);
+      const rendered = drawPointTrails(g, trails, state.trailPool, scope, now, lineFadeMs, settings);
       if (!rendered && !xyReady) {
         drawIdleMessage(g, scope);
       }
@@ -530,17 +561,36 @@ function renderTrace(g, state, trace, scope, style, xyReady, settings) {
   }
 }
 
-function addLineTrail(trails, trace, timestamp) {
-  const coords = new Float32Array(trace.count * 2);
+function addLineTrail(state, trace, timestamp) {
+  const trails = state.lineTrails || (state.lineTrails = []);
+  const pool = state.trailPool || (state.trailPool = []);
+  while (trails.length >= MAX_TRAIL_FRAMES) releaseTrail(pool, trails.shift());
+  let coords = pool.pop();
+  if (!(coords instanceof Float32Array) || coords.length < trace.count * 2) {
+    coords = new Float32Array(trace.count * 2);
+  }
   coords.set(trace.buffer.subarray(0, trace.count * 2));
   trails.push({ coords, count: trace.count, time: timestamp });
 }
 
-function drawLineTrails(g, trails, scope, now, fadeMs, settings) {
+function releaseTrail(pool, trail) {
+  if (trail?.coords instanceof Float32Array && pool.length < MAX_TRAIL_FRAMES) {
+    pool.push(trail.coords);
+  }
+}
+
+function clearTrails(state) {
+  const trails = state.lineTrails || [];
+  const pool = state.trailPool || (state.trailPool = []);
+  for (const trail of trails) releaseTrail(pool, trail);
+  trails.length = 0;
+}
+
+function drawLineTrails(g, trails, pool, scope, now, fadeMs, settings) {
   if (!trails.length) return false;
 
   const cutoff = now - fadeMs;
-  const keep = [];
+  let keepCount = 0;
   let drawn = false;
 
   g.save();
@@ -549,13 +599,19 @@ function drawLineTrails(g, trails, scope, now, fadeMs, settings) {
   g.clip();
 
   for (const trail of trails) {
-    if (trail.time < cutoff) continue;
+    if (trail.time < cutoff) {
+      releaseTrail(pool, trail);
+      continue;
+    }
     const age = now - trail.time;
     const fade = Math.max(0, 1 - age / fadeMs);
-    if (fade <= 0) continue;
+    if (fade <= 0) {
+      releaseTrail(pool, trail);
+      continue;
+    }
 
     drawn = true;
-    keep.push(trail);
+    trails[keepCount++] = trail;
 
     g.save();
     g.globalAlpha = (settings?.trailBaseAlpha ?? 0.35) + (settings?.trailBoostAlpha ?? 0.65) * fade;
@@ -568,8 +624,7 @@ function drawLineTrails(g, trails, scope, now, fadeMs, settings) {
 
   g.restore();
 
-  trails.length = 0;
-  Array.prototype.push.apply(trails, keep);
+  trails.length = keepCount;
 
   return drawn;
 }
@@ -611,11 +666,11 @@ function beginTracePath(g, coords, count, settings) {
   g.quadraticCurveTo(coords[prev], coords[prev + 1], coords[last], coords[last + 1]);
 }
 
-function drawPointTrails(g, trails, scope, now, fadeMs, settings) {
+function drawPointTrails(g, trails, pool, scope, now, fadeMs, settings) {
   if (!trails.length) return false;
 
   const cutoff = now - fadeMs;
-  const keep = [];
+  let keepCount = 0;
   let drawn = false;
   const pointSize = settings?.pointSize ?? 1.4;
   const half = pointSize / 2;
@@ -626,13 +681,19 @@ function drawPointTrails(g, trails, scope, now, fadeMs, settings) {
   g.clip();
 
   for (const trail of trails) {
-    if (trail.time < cutoff) continue;
+    if (trail.time < cutoff) {
+      releaseTrail(pool, trail);
+      continue;
+    }
     const age = now - trail.time;
     const fade = Math.max(0, 1 - age / fadeMs);
-    if (fade <= 0) continue;
+    if (fade <= 0) {
+      releaseTrail(pool, trail);
+      continue;
+    }
 
     drawn = true;
-    keep.push(trail);
+    trails[keepCount++] = trail;
 
     for (let i = 0; i < trail.count; i++) {
       const idx = i * 2;
@@ -645,8 +706,7 @@ function drawPointTrails(g, trails, scope, now, fadeMs, settings) {
 
   g.restore();
 
-  trails.length = 0;
-  Array.prototype.push.apply(trails, keep);
+  trails.length = keepCount;
 
   return drawn;
 }
@@ -703,6 +763,10 @@ function getNow() {
 function computeAgcGain(state, xyData, nowTs) {
   const attackTau = 0.001; // 1 ms
   const releaseDbPerS = 10;
+  if (xyData.seq > 0 && xyData.seq === state.agcLastXySeq) {
+    return { gainDb: state.agcGainDb, gain: dbToLinear(state.agcGainDb) };
+  }
+  state.agcLastXySeq = xyData.seq;
   const dt = state.agcLastTs ? Math.max(0, (nowTs - state.agcLastTs) / 1000) : 0;
   state.agcLastTs = nowTs;
 
@@ -785,7 +849,7 @@ function drawCorrelationBar(g, centerX, y, w, h, val, negativePeak) {
   g.lineWidth = 1;
   g.strokeRect(cubeX, cubeY, cubeSize, cubeSize);
   g.beginPath(); g.moveTo(mid, y); g.lineTo(mid, y + h); g.stroke();
-  if (Number.isFinite(negativePeak) && negativePeak < 0.999) {
+  if (Number.isFinite(negativePeak) && negativePeak < -0.001) {
     const markerX = clampCenter(mid + (clamp1(negativePeak) * 0.5) * w);
     g.fillStyle = WARN_COLOR;
     g.beginPath();