Recover analyzer DSP and realtime pipeline corrections

TODO.md

@@ -0,0 +1,171 @@
+# Phoenix Analyzer - Soll-/Ist-To-do
+
+## Verbindliches Ziel
+
+- Referenz ist der RTW PortaMonitor 1064X/1064X-PLUS, insbesondere dessen RTA-, PPM-, Peakmeter-, Goniometer- und Korrelationsverhalten.
+- Der primäre RTW-nahe RTA arbeitet als IIR-Fractional-Octave-Filterbank. FFT bleibt eine optionale, getrennt gekennzeichnete Spektrumsansicht.
+- Der RTW-RTA-Modus soll 31 Bänder in 1/3-Oktaven von 20 Hz bis 20 kHz sowie ein Verhalten entsprechend IEC 225/ANSI Class 2 beziehungsweise der passenden aktuellen Nachfolgenorm bieten.
+- Vorgesehene RTA-Modi: Fast, Medium, Slow, Average und Peak; Peak Hold 2,5 s, 4 s oder manuell.
+- Zwischen hörbarem Signal und Anzeige soll nur die unvermeidbare Mess- und Bildschirmlatenz liegen. Alte Messframes dürfen niemals eine anwachsende Verzögerung erzeugen.
+- Normbedingte Ballistiken werden nicht künstlich verkürzt. Technische Transportlatenz und gewollte Instrumententrägheit werden getrennt behandelt.
+- LUFS und LRA bleiben vorerst außerhalb dieser Aufgabenliste.
+
+## Was bereits vorhanden und grundsätzlich brauchbar ist
+
+- Direkte ALSA-Aufnahme mit kleiner Standardperiode von 128 Samples.
+- Ein IIR-RTA ist bereits vorhanden und in Frontend und Backend der Standardmodus.
+- Die 31 RTW-Mittenfrequenzen für 1/3-Oktaven von 20 Hz bis 20 kHz sind bereits hinterlegt.
+- Zusätzlich existieren 1/6- und 1/12-Oktav-Modi als Phoenix-Erweiterungen.
+- RTA-Bandwerte und Peakwerte werden getrennt geführt.
+- DIN-PPM, EBU-PPM, True Peak, VU, RMS, Goniometer, Korrelation, Waveform und Spektrogramm sind grundsätzlich vorhanden.
+- Das Frontend zeichnet mit bis zu 60 Hz und verwendet für Waveform und Spektrogramm teilweise Worker.
+- Konfigurierbare Eingangspegelkorrektur und ein L/R-Laufzeitausgleich existieren.
+
+Diese vorhandenen Funktionen sind nicht automatisch messtechnisch korrekt. Die folgenden Punkte beschreiben den jeweiligen Soll-/Ist-Unterschied.
+
+## Priorität 0 - Anwachsende Anzeigeverzögerung verhindern
+
+- [x] **1. WebSocket auf "latest value wins" umstellen**
+  - **Soll:** Ein langsamer Client erhält immer den neuesten Messzustand; alte Zustände werden verworfen.
+  - **Ist:** Der interne Kanal ist auf 32 Frames begrenzt; der WebSocket sendet im 16-ms-Takt und leert vor jedem Versand bis zum neuesten Zustand. Spektrogrammdaten laufen getrennt.
+  - **Abnahme:** Lokaler Laufzeittest liefert 68 aktuelle Messframes in 1,1 s; alte Zustände werden beim Leeren verworfen.
+
+- [x] **2. Mess-, Visualisierungs- und Konfigurationsdaten trennen**
+  - **Soll:** DSP läuft samplegenau; übertragen wird nur so häufig und so umfangreich wie für die jeweilige Anzeige nötig.
+  - **Ist:** Skalare Messzustände laufen mit etwa 60 JSON-Paketen/s. Spektrogramm sowie Goniometer/Waveform besitzen getrennte, kompakte Binär-WebSockets. Roh-Waveformsamples werden nicht mehr in jedem Capture-Frame vervielfacht; Waveform-Hüllkurven werden beim serverseitigen Leeren lückenlos zusammengeführt. Das doppelte RTA-Bandfeld wurde vollständig entfernt; Konfiguration wird nur separat bei Änderungen synchronisiert.
+  - **Interne Last:** Der Verteiler reicht Messframes als gemeinsam genutzte Referenz weiter. Beim Verwerfen alter Frames werden deshalb keine kompletten Spektrogramm-, XY- und Waveformvektoren mehr kopiert.
+  - **Geprüft:** Protokolltests prüfen Header, Nutzdaten und beschädigte Paketlängen. Ein Servertest stellt sicher, dass große Visualisierungsfelder nicht wieder im JSON-Messstrom landen.
+  - **Abnahme:** Datenwege sind softwareseitig getrennt; die Lastmessung auf der Zielhardware bleibt Bestandteil der End-to-End-Abnahme unter Punkt 17.
+
+- [x] **3. Browser-Verarbeitung auf den neuesten Zustand begrenzen**
+  - **Soll:** Pro Bildschirmframe wird höchstens der neueste vollständige Messzustand verarbeitet.
+  - **Ist:** Der Browser besitzt für Messwerte, Spektrogramm und Visualisierungsdaten jeweils einen Single-Slot-Puffer und verarbeitet höchstens einen aktuellen Zustand pro Animation Frame. Während einer laufenden Verarbeitung ersetzt ein neuer Zustand den wartenden alten. Nicht mehr steigende Sequenznummern werden verworfen.
+  - **Abnahme:** Es existiert kein unbeschränktes Paket- oder Promise-Backlog mehr.
+
+- [x] **3a. Spektrogramm dauerhaft echtzeitfähig machen**
+  - **Ist:** Inkrementelles Spaltenzeichnen statt Vollbild-Neuberechnung, Worker-ACK/Single-Slot, 750-ms-Watchdog mit sauberem Neustart, begrenzter Sprung statt nachträglichem Aufholen sowie eigener Binärstrom mit Quellsequenz.
+  - **Geschwindigkeit:** Feste Zeitbasis von 60 CSS-Pixeln/s bei 1×; 0,5×, 2×, 4× und 6× skalieren exakt und bleiben unabhängig von FFT-Größe und Display-DPI. Gamma und Geschwindigkeit werden global gespeichert.
+  - **Abnahme:** Automatische Tests prüfen alle Geschwindigkeiten, FFT-Größenunabhängigkeit, DPI-Skalierung, Worker-ACK, ausschließlich inkrementelles Hochladen der neuen Bildspalte und 60.000 Spalten als synthetischen Zehn-Minuten-Lauf.
+
+## Priorität 1 - RTW-naher IIR-RTA
+
+- [x] **4. IIR verbindlich als RTW-RTA-Modus behandeln**
+  - **Soll:** RTW-Modus bedeutet eindeutig IIR-Filterbank; FFT ist eine gesonderte Zusatzansicht.
+  - **Ist:** Backend, gespeicherte Konfiguration, Optionsdialog und Laufzeitprofil erzwingen im RTW-Layout jetzt IIR, 31 Dritteloktavbänder, Normalbereich und Filterordnung 6. Alte Browserkonfigurationen können den Motor nicht mehr heimlich auf FFT zurückstellen; das Backend-Paket ist für die Anzeige maßgeblich.
+  - **Geprüft:** Ein automatischer Profiltest prüft sowohl das gesperrte RTW-Profil als auch die weiterhin freie IEC-/Phoenix-Erweiterung.
+  - **Abnahme:** Das RTW-Profil startet reproduzierbar immer mit der validierten IIR-Filterbank.
+
+- [ ] **5. IIR-Filterbank fachgerecht für 31 Dritteloktavbänder auslegen**
+  - **Soll:** 31 Bänder, 20 Hz bis 20 kHz, korrekte Mittenfrequenzen, Bandkanten und Class-2-Toleranzen.
+  - **Ist:** Der RTW-Kern verwendet jetzt je Band einen vollständigen Butterworth-Bandpass sechster Ordnung aus drei unterschiedlichen SOS-Sektionen mit vorverzerrten Bandgrenzen und Normierung auf die Bandmitte. Die Anzeige behält die gerundeten RTW-Nominalwerte, während die Filter mit den exakten IEC-Basis-10-Mitten und -Bandkanten rechnen. Koeffizienten, Zustände und Leistungsrechnung laufen intern in `f64`, damit insbesondere das 20-Hz-Band stabil und genau bleibt.
+  - **Geprüft:** Automatische Frequenzgang- und Zeitbereichstests prüfen alle 31 Mitten, beide -3-dB-Bandkanten, Nachbarbandunterdrückung sowie 44,1, 48 und 96 kHz. A-, C- und Z-Bewertung werden sampleweise vor der Filterbank angewandt und gegen Normformeln geprüft.
+  - **Noch offen:** Der vollständige Class-2-Toleranzmasken-Nachweis und eine formelle Geräte-/Laborvalidierung fehlen; deshalb bleibt der Gesamtpunkt offen.
+  - **Abnahme:** Jedes der 31 Bänder besteht automatisierte Sweep- und Pegeltests innerhalb der festgelegten Toleranzen.
+
+- [ ] **6. RTW-Integrationsmodi vollständig und energetisch korrekt implementieren**
+  - **Soll:** Fast, Medium, Slow, Average und Peak mit dokumentiertem RTW-nahem Verhalten.
+  - **Ist:** Fast, Medium, Slow und Impulse integrieren jetzt blockgrößenunabhängig im Leistungsbereich; Average bildet das kumulative Energiemittel, Peak den höchsten gefilterten Samplewert. Erst danach erfolgt die dB-Umrechnung.
+  - **Geprüft:** Ein Regressionstest bestätigt identische Integration bei unterschiedlichen Blockgrößen.
+  - **Noch offen:** Die gewählte Medium-Zeitkonstante von 0,5 s und die übrigen Profile müssen noch mit vollständigem RTW-Handbuch oder Referenzgerät abgeglichen werden; deshalb bleibt der Gesamtpunkt offen.
+  - **Abnahme:** Sprung-, Burst- und Rauschtests zeigen für jeden Modus reproduzierbares RTW-nahes Verhalten.
+
+- [ ] **7. Peak Hold und Bandspeicher wie beim PortaMonitor ergänzen**
+  - **Soll:** Peak Hold 2,5 s, 4 s oder manuell; Speicher für acht Bänder plus Hold.
+  - **Ist:** Die Anzeige unterstützt jetzt Peak Hold 2,5 s, 4 s und manuell. Der ältere kontinuierliche Backend-Peak sowie der achtbandige RTW-Speicher sind noch nicht vollständig ersetzt beziehungsweise ergänzt.
+  - **Falsch/unvollständig:** Ein kontinuierlich fallender Peak ist funktional nicht dasselbe wie Peak Hold.
+  - **Aufgabe:** Hold-Zeit, manuellen Hold, Reset, Rücklauf nach Hold-Ende und acht auswählbare Speicherbänder implementieren. Aktuellwert und Holdwert visuell eindeutig trennen.
+  - **Abnahme:** Hold-Zeiten und Reset-Verhalten stimmen zeitlich und visuell mit der Referenz überein.
+
+- [ ] **8. RTA-Anzeigeoptionen am PortaMonitor-Profil ausrichten**
+  - **Soll:** 31 Dritteloktavbänder, wählbarer Mess-/Anzeigebereich von 15, 30 oder 45 dB und optionales zweikanaliges Peakmeter.
+  - **Ist:** Mehrere BPO-Modi, RTW-/IEC-Layouts, frei konfigurierte Skalierung und Peak-Overlay sind vorhanden.
+  - **Unstimmig:** Phoenix-Erweiterungen und originale RTW-Funktionen sind nicht getrennt; die Skalen entsprechen nicht zwingend den drei RTW-Bereichen.
+  - **Aufgabe:** Ein gesperrtes RTW-1064X-Profil mit den Originaloptionen anbieten. 1/6 und 1/12 Oktave sowie andere Bereiche ausdrücklich als Phoenix-Erweiterung kennzeichnen.
+  - **Abnahme:** Das RTW-Profil lässt sich direkt anhand des Datenblatts und Referenzgeräts nachvollziehen.
+
+## Priorität 2 - Gemeinsame Messgrundlage
+
+- [x] **9. Tatsächliche ALSA-Parameter verwenden**
+  - **Soll:** Alle Filter, Zeitkonstanten, Frequenzachsen und Aufnahmen verwenden die tatsächlich ausgehandelte Hardwarekonfiguration.
+  - **Ist:** Phoenix liest Rate, Periode und Puffergröße nach der ALSA-Aushandlung zurück. DSP, RTA-Filter, Zeitkonstanten, Aufnahme-Metadaten, Status und Browserfrequenzachse verwenden die tatsächliche Rate; die tatsächliche Periode wird ebenfalls im Messpaket übertragen.
+  - **Geprüft:** RTA-Filtertests laufen bei 44,1, 48 und 96 kHz; die abschließende Prüfung mit real unterschiedlich aushandelnder Hardware bleibt Teil der Geräteabnahme.
+  - **Abnahme:** Sweep- und Zeitmessungen bleiben bei verschiedenen unterstützten Hardware-Raten korrekt.
+
+- [ ] **10. True Peak kontinuierlich und blockübergreifend korrigieren**
+  - **Soll:** Intersample-Peaks werden unabhängig von ihrer Lage zum ALSA-Block zuverlässig erkannt.
+  - **Ist:** Eine 4-fache Sinc-Interpolation mit kurzer Historie existiert.
+  - **Falsch/kaputt:** Ungefähr die letzten acht Intervalle jedes Capture-Blocks werden nicht interpoliert und können zu niedrige dBTP-Werte liefern.
+  - **Aufgabe:** Kontinuierlichen Oversampling-Filter mit vollständiger Historie verwenden und gegen ITU-Testmaterial sowie synthetische Grenzfälle prüfen.
+  - **Abnahme:** Gleiche Peakwerte unabhängig von Blockgrenze, Periodengröße und Samplerate.
+
+- [x] **11. DIN- und EBU-PPM softwareseitig norm- und RTW-nah auslegen**
+  - **Soll:** Richtige Skalen, Referenzpegel, Tonburst-Reaktion, Integration, Rücklauf, Peak Hold, Peak Memory und Over-Anzeige.
+  - **Ist:** Blockunabhängige DIN-/EBU-Quasi-Peak-Detektoren mit 8-facher bandbegrenzter Interpolation; DIN-Profil 10 ms und 20 dB/1,5 s, EBU Type IIb 10 ms und 24 dB/2,8 s. Der sofortige DIN-Modus ist getrennt und ausdrücklich nicht normgerecht gekennzeichnet.
+  - **Geprüft:** Vollständige EBU-5-kHz-Tonburst-Tabelle, beide Rücklaufzeiten, Startverhalten, Polarität und EBU-Frequenzgang 31,5 Hz bis 16 kHz laufen als automatische Regressionstests. Die Balken übernehmen den Backendwert ohne zweite Anstiegsballistik.
+  - **Noch offen:** Absolute Pegel- und Skalenprüfung mit kalibriertem Generator, Eingangs-Hardware und realem RTW-Gerät bleibt unter Punkt 16 erforderlich.
+  - **Abnahme:** Softwaretests bestehen; die endgültige Aussage zur Messgeräte-Konformität erfolgt erst nach der Hardwarevergleichsmessung.
+
+- [ ] **12. VU und RMS eindeutig und reproduzierbar definieren**
+  - **Soll VU:** RTW-artige Moving-Coil-Ballistik mit richtigem Einschwingen, Rücklauf und Überschwingen.
+  - **Ist VU:** 300-ms-Rechteckmittel der gleichgerichteten Samples.
+  - **Falsch VU:** Boxcar-Mittelung entspricht nicht der mechanischen VU-Ballistik.
+  - **Soll RMS:** Dokumentiertes gleitendes Messfenster mit eindeutigem dBFS-/Kalibrierbezug.
+  - **Ist RMS:** RMS nur über den aktuellen ALSA-Block, bei 128 Samples etwa 2,67 ms.
+  - **Falsch RMS:** Wert und Unruhe hängen von der Periodengröße ab.
+  - **Aufgabe:** Beide Detektoren unabhängig von der Capture-Blockgröße implementieren und separat testen.
+  - **Abnahme:** Identische Werte und Ballistiken bei verschiedenen ALSA-Perioden.
+
+- [ ] **13. FFT-Modus als optionale Spektrumsansicht fachlich korrigieren**
+  - **Soll:** FFT ist eine korrekte Zusatzansicht, aber nicht die RTW-IIR-Referenz.
+  - **Ist:** FFT-RTA und Spektrogramm sind vorhanden.
+  - **Falsch:** FFT-Bins werden innerhalb eines Bandes normiert gemittelt statt zur Bandenergie summiert. Rauschsignale und unterschiedlich breite Bänder werden dadurch falsch bewertet.
+  - **Aufgabe:** Binleistungen energetisch integrieren, Fensterleistung korrekt kompensieren und FFT-Ergebnisse gegen die IIR-Referenz testen.
+  - **Abnahme:** Konsistente Pegel bei FFT-Größenwechseln und eindeutig getrennte Kennzeichnung im UI.
+
+## Priorität 3 - Stereoanzeigen und visuelles RTW-Verhalten
+
+- [ ] **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.
+  - **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.
+  - **Abnahme:** Statische und dynamische Testsignale stimmen innerhalb der festgelegten Toleranz mit der Referenz überein.
+
+## Priorität 4 - Nachweis und dauerhafte Absicherung
+
+- [ ] **16. RTW-Referenzprofil vervollständigen**
+  - **Soll:** Modell, Firmware, Eingangsart, Skala, Referenzpegel und jedes nachzubildende Preset sind dokumentiert.
+  - **Ist:** Das Datenblatt des 1063X-/1064X-PLUS liegt vor und definiert viele Optionen, aber nicht alle internen Zeitkonstanten und Toleranzdetails.
+  - **Fehlt:** Vollständiges Bedienhandbuch und/oder reale Vergleichsmessungen.
+  - **Aufgabe:** Handbuchdaten und Messprotokolle ergänzen; exakt nachzubildende Funktionen von bewussten Phoenix-Erweiterungen trennen.
+  - **Abnahme:** Jede RTW-nahe Option besitzt eine nachvollziehbare Quelle oder ein Referenzmessprotokoll.
+
+- [ ] **17. End-to-End-Latenz messen und begrenzen**
+  - **Soll:** Bei 60-Hz-Display typisch unter 25 ms zusätzliche Anzeigeverzögerung, normal unter 35 ms; bei 120 Hz möglichst 10 bis 20 ms. Keine anwachsende Warteschlange.
+  - **Ist:** 128-Sample-Capture und 60-Hz-Rendering sind grundsätzlich schnell, aber es gibt keine durchgängige Latenzmessung.
+  - **Fehlt:** Zeitstempel für Capture, DSP, Versand, Browserempfang und tatsächlichen Paint.
+  - **Aufgabe:** Monotone Zeitstempel, Median/P95/Maximum sowie sicht-/hörbaren Impulstest einführen. Instrumentenballistik separat ausweisen.
+  - **Abnahme:** Ziele werden unter realistischer Volllast eingehalten und Regressionen automatisch erkannt.
+
+- [ ] **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.
+  - **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.
+
+## Empfohlene Bearbeitungsreihenfolge
+
+1. Punkte 1 bis 3: anwachsende Transport- und Browserlatenz beseitigen.
+2. Punkt 9: korrekte gemeinsame Zeit- und Frequenzbasis herstellen.
+3. Punkte 4 bis 8: IIR-RTA als RTW-Kern verbindlich und korrekt auslegen.
+4. Punkte 10 bis 15: weitere Messinstrumente korrigieren und abstimmen.
+5. Punkte 16 bis 18: Referenz, Latenz und Messrichtigkeit dauerhaft nachweisen.

reference-config/phoenix-global-config.analyzer.json

@@ -9,17 +9,19 @@
   "alMarkersEnabled": false,
   "meterBarThin": 0.55,
   "panelDividersEnabled": true,
-  "ppmDinAttackMs": 5.0,
+  "ppmDinAttackMs": 10.0,
-  "ppmDinDecayDbPerS": 11.8,
+  "ppmDinDecayDbPerS": 13.333333,
   "ppmDinFastAttack": false,
   "ppmDinLoudnessBoxes": true,
   "ppmEbuAttackMs": 10.0,
-  "ppmEbuDecayDbPerS": 8.6,
+  "ppmEbuDecayDbPerS": 8.571429,
   "lufsIWindowMin": 4,
   "lufsINormEnabled": false,
   "ppmDinLoudnessOffsetDb": 0.0,
   "xyPoints": 1024,
   "gonioDisplayGainDb": -5.0,
+  "spectroGamma": 0.9,
+  "spectroScrollMode": 1.0,
   "phaseAmplitudeMode": "ppm-din",
   "recordOutputFormat": "wav",
   "recordMp3BitrateKbps": 192,

reference-config/phoenix-global-config.volumio.json

@@ -9,17 +9,19 @@
   "alMarkersEnabled": false,
   "meterBarThin": 0.55,
   "panelDividersEnabled": true,
-  "ppmDinAttackMs": 5.0,
+  "ppmDinAttackMs": 10.0,
-  "ppmDinDecayDbPerS": 11.8,
+  "ppmDinDecayDbPerS": 13.333333,
   "ppmDinFastAttack": false,
   "ppmDinLoudnessBoxes": true,
   "ppmEbuAttackMs": 10.0,
-  "ppmEbuDecayDbPerS": 8.6,
+  "ppmEbuDecayDbPerS": 8.571429,
   "lufsIWindowMin": 4,
   "lufsINormEnabled": false,
   "ppmDinLoudnessOffsetDb": 0.0,
   "xyPoints": 1024,
   "gonioDisplayGainDb": -5.0,
+  "spectroGamma": 0.9,
+  "spectroScrollMode": 1.0,
   "phaseAmplitudeMode": "ppm-din",
   "recordOutputFormat": "wav",
   "recordMp3BitrateKbps": 192,

scripts/test_binary_protocol.mjs

@@ -0,0 +1,61 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import vm from 'node:vm';
+
+const source = fs.readFileSync(new URL('../www/core/binary_protocol.js', import.meta.url), 'utf8');
+const context = vm.createContext({ ArrayBuffer, DataView, Float32Array, Number });
+vm.runInContext(source.replaceAll('export function', 'function'), context, {
+  filename: 'binary_protocol.js',
+});
+
+function spectroPacket() {
+  const buffer = new ArrayBuffer(28);
+  const view = new DataView(buffer);
+  view.setUint32(0, 0x50585350, true);
+  view.setUint32(4, 42, true);
+  view.setUint32(8, 48000, true);
+  view.setUint32(12, 8192, true);
+  view.setUint32(16, 2, true);
+  view.setFloat32(20, -80, true);
+  view.setFloat32(24, -12.5, true);
+  return buffer;
+}
+
+function visualsPacket() {
+  const buffer = new ArrayBuffer(64);
+  const view = new DataView(buffer);
+  view.setUint32(0, 0x50585653, true);
+  view.setUint16(4, 1, true);
+  view.setUint16(6, 3, true);
+  view.setUint32(8, 7, true);
+  view.setUint32(12, 2, true);
+  view.setUint32(16, 2, true);
+  view.setUint16(20, 1, true);
+  view.setUint32(24, 5, true);
+  view.setUint32(28, 48000, true);
+  [-0.5, 0.25, 0.5, -0.25, -0.5, 0.5, -0.25, 0.25]
+    .forEach((value, index) => view.setFloat32(32 + index * 4, value, true));
+  return buffer;
+}
+
+const spectro = context.decodePhoenixSpectroBuffer(spectroPacket());
+assert.equal(spectro.seq, 42);
+assert.equal(spectro.sampleRate, 48000);
+assert.equal(spectro.fftSize, 8192);
+assert.deepEqual(Array.from(spectro.bins), [-80, -12.5]);
+
+const visual = context.decodePhoenixVisualsBuffer(visualsPacket());
+assert.equal(visual.seq, 7);
+assert.deepEqual(Array.from(visual.left), [-0.5, 0.5]);
+assert.deepEqual(Array.from(visual.right), [0.25, -0.25]);
+assert.equal(visual.wave.columns, 2);
+assert.equal(visual.wave.channels, 1);
+assert.deepEqual(Array.from(visual.wave.data), [-0.5, 0.5, -0.25, 0.25]);
+
+assert.equal(context.decodePhoenixSpectroBuffer(spectroPacket().slice(0, 24)), null);
+assert.equal(context.decodePhoenixVisualsBuffer(visualsPacket().slice(0, 60)), null);
+const wrongVersion = visualsPacket();
+new DataView(wrongVersion).setUint16(4, 2, true);
+assert.equal(context.decodePhoenixVisualsBuffer(wrongVersion), null);
+
+console.log('binary protocol regression tests passed');

scripts/test_rta_profile.mjs

@@ -0,0 +1,41 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import vm from 'node:vm';
+
+const source = fs.readFileSync(new URL('../www/core/audio.js', import.meta.url), 'utf8');
+const functionSource = source.match(/export function buildRtaRuntimeConfig[\s\S]*?\n\}/)?.[0];
+assert.ok(functionSource, 'buildRtaRuntimeConfig must remain testable');
+const context = vm.createContext({
+  Number,
+  getRtwCenters(mode) {
+    return mode === '1_3' ? new Array(31).fill(0) : [];
+  },
+});
+vm.runInContext(functionSource.replace('export function', 'function'), context);
+
+const forced = context.buildRtaRuntimeConfig({
+  RTA_BAR_LAYOUT: 'rtw',
+  RTA_ENGINE: 'fft',
+  RTA_BPO_MODE: '1_12',
+  RTA_FREQ_RANGE: 'lf',
+  RTA_IIR_ORDER: 2,
+});
+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);
+
+const extension = context.buildRtaRuntimeConfig({
+  RTA_BAR_LAYOUT: 'iec',
+  RTA_ENGINE: 'fft',
+  RTA_BPO_MODE: '1_12',
+  RTA_FREQ_RANGE: 'lf',
+  RTA_IIR_ORDER: 8,
+});
+assert.equal(extension.engine, 'fft');
+assert.equal(extension.bpo, '1_12');
+assert.equal(extension.freqRange, 'lf');
+assert.equal(extension.order, 8);
+
+console.log('RTA profile regression tests passed');

scripts/test_spectrogram.mjs

@@ -0,0 +1,113 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import vm from 'node:vm';
+
+const viewSource = fs.readFileSync(new URL('../www/views/spectrogram.js', import.meta.url), 'utf8');
+const timingSource = viewSource.match(/export function stepScrollAccumulator[\s\S]*?\n\}/)?.[0];
+assert.ok(timingSource, 'stepScrollAccumulator must remain testable');
+const timingContext = vm.createContext({ Number, Math });
+vm.runInContext(timingSource.replace('export function', 'function'), timingContext);
+const { stepScrollAccumulator } = timingContext;
+const pixelsSource = viewSource.match(/export function spectrogramPixelsPerSourceFrame[\s\S]*?\n\}/)?.[0];
+assert.ok(pixelsSource, 'spectrogramPixelsPerSourceFrame must remain testable');
+timingContext.BASE_SCROLL_CSS_PX_PER_SECOND = 60;
+vm.runInContext(pixelsSource.replace('export function', 'function'), timingContext);
+const { spectrogramPixelsPerSourceFrame } = timingContext;
+
+function emittedColumns(rate, frames, pixelScale = 1) {
+  let accumulator = 0;
+  let columns = 0;
+  for (let frame = 0; frame < frames; frame++) {
+    const step = stepScrollAccumulator(accumulator, rate * pixelScale, 1);
+    accumulator = step.accumulator;
+    columns += step.columns;
+  }
+  return columns;
+}
+
+assert.equal(emittedColumns(0.5, 20), 10, '0.5x must emit every second source frame');
+assert.equal(emittedColumns(1, 20), 20);
+assert.equal(emittedColumns(2, 20), 40);
+assert.equal(emittedColumns(4, 20), 80);
+assert.equal(emittedColumns(6, 20), 120);
+assert.equal(emittedColumns(1, 10, 1.7), 17, 'DPR scaling must preserve CSS scroll speed');
+
+function emittedInOneSecond(rate, fftSize) {
+  const sampleRate = 48000;
+  const hop = Math.max(128, Math.floor(fftSize / 8));
+  const sourceFrames = sampleRate / hop;
+  const pixelsPerFrame = spectrogramPixelsPerSourceFrame(rate, sampleRate, fftSize);
+  return emittedColumns(pixelsPerFrame, sourceFrames);
+}
+
+assert.equal(emittedInOneSecond(0.5, 4096), 30);
+assert.equal(emittedInOneSecond(1, 4096), 60);
+assert.equal(emittedInOneSecond(1, 8192), 60, 'FFT size must not alter real-time scroll speed');
+assert.equal(emittedInOneSecond(2, 8192), 120);
+assert.equal(emittedInOneSecond(4, 8192), 240);
+assert.equal(emittedInOneSecond(6, 8192), 360);
+
+const messages = [];
+const calls = { drawImage: 0, putImageData: [] };
+const context2d = {
+  imageSmoothingEnabled: true,
+  globalCompositeOperation: 'source-over',
+  fillStyle: '#000',
+  save() {},
+  restore() {},
+  fillRect() {},
+  drawImage() { calls.drawImage += 1; },
+  createImageData(width, height) {
+    return { width, height, data: new Uint8ClampedArray(width * height * 4) };
+  },
+  putImageData(image, x, y) { calls.putImageData.push({ image, x, y }); },
+};
+const canvas = {
+  width: 0,
+  height: 0,
+  getContext() { return context2d; },
+};
+const workerContext = vm.createContext({
+  self: {},
+  postMessage(message) { messages.push(message); },
+  performance: { now: (() => { let now = 0; return () => ++now; })() },
+  Float32Array,
+  Uint8ClampedArray,
+  Number,
+  Math,
+});
+const workerSource = fs.readFileSync(new URL('../www/workers/spectrogram.worker.js', import.meta.url), 'utf8');
+vm.runInContext(workerSource, workerContext, { filename: 'spectrogram.worker.js' });
+
+workerContext.self.onmessage({
+  data: { type: 'init', canvas, width: 8, height: 4, topDb: 0, bottomDb: -80, gamma: 1 },
+});
+assert.equal(messages.at(-1)?.type, 'ready');
+
+workerContext.self.onmessage({
+  data: { type: 'column', id: 7, repeat: 2, data: new Float32Array([-80, -40, -20, 0]) },
+});
+const ack = messages.at(-1);
+assert.equal(ack.type, 'drawn');
+assert.equal(ack.id, 7);
+assert.equal(ack.repeat, 2);
+assert.equal(calls.drawImage, 1, 'existing canvas should be shifted once');
+assert.equal(calls.putImageData.length, 1, 'only the new stripe should be uploaded');
+assert.equal(calls.putImageData[0].image.width, 2);
+assert.equal(calls.putImageData[0].x, 6);
+
+// Roughly ten minutes at 100 source columns/s. The worker has no history or
+// pending-message collection that can grow with runtime.
+messages.length = 0;
+context2d.putImageData = () => {};
+const longRunColumn = new Float32Array([-80, -40, -20, 0]);
+for (let index = 0; index < 60_000; index++) {
+  workerContext.self.onmessage({
+    data: { type: 'column', id: 100 + index, repeat: 1, data: longRunColumn },
+  });
+}
+assert.equal(messages.length, 60_000);
+assert.equal(messages.at(-1)?.type, 'drawn');
+assert.equal(messages.at(-1)?.id, 60_099);
+
+console.log('spectrogram timing and worker tests passed');

scripts/test_websocket_runtime.mjs

@@ -0,0 +1,36 @@
+import assert from 'node:assert/strict';
+
+const base = process.env.PHOENIX_TEST_WS_BASE || 'ws://127.0.0.1:8789';
+
+function openSocket(path) {
+  return new Promise((resolve, reject) => {
+    const socket = new WebSocket(`${base}${path}`);
+    socket.addEventListener('open', () => resolve(socket), { once: true });
+    socket.addEventListener('error', () => reject(new Error(`failed to open ${path}`)), { once: true });
+  });
+}
+
+const sockets = await Promise.all([
+  openSocket('/api/v1/metrics/ws'),
+  openSocket('/api/v1/spectro/ws'),
+  openSocket('/api/v1/visuals/ws'),
+]);
+const [metrics] = sockets;
+let count = 0;
+let lastSeq = 0;
+let invalidPayload = false;
+metrics.addEventListener('message', (event) => {
+  const frame = JSON.parse(String(event.data));
+  const seq = Number(frame.seq);
+  if (seq <= lastSeq || 'spectro' in frame || 'wave_env' in frame || 'xy_l' in frame || 'wave_l' in frame) {
+    invalidPayload = true;
+  }
+  lastSeq = seq;
+  count += 1;
+});
+
+await new Promise((resolve) => setTimeout(resolve, 1100));
+sockets.forEach((socket) => socket.close());
+assert.equal(invalidPayload, false, 'metrics must be ordered and contain no large visual payloads');
+assert.ok(count >= 50 && count <= 75, `expected about 60 metrics/s, received ${count}`);
+console.log(`runtime websocket test passed (${count} metrics in 1.1 s; all three streams opened)`);

src/config.rs

@@ -80,7 +80,12 @@ impl PhoenixConfig {
                 .unwrap_or(2 * 1024 * 1024 * 1024),
             lr_fractional_delay_enabled: std::env::var("PHOENIX_LR_FRAC_DELAY_ENABLED")
                 .ok()
-                .map(|v| matches!(v.trim().to_ascii_lowercase().as_str(), "1" | "true" | "yes" | "on"))
+                .map(|v| {
+                    matches!(
+                        v.trim().to_ascii_lowercase().as_str(),
+                        "1" | "true" | "yes" | "on"
+                    )
+                })
                 .unwrap_or(true),
             lr_fractional_delay_samples: std::env::var("PHOENIX_LR_FRAC_DELAY_SAMPLES")
                 .ok()

src/correlation.rs

@@ -0,0 +1,151 @@
+//! Continuous stereo correlation meter.
+//!
+//! The detector integrates L², R² and L·R with the same time constant and
+//! derives the normalized correlation only afterwards. Its timing therefore
+//! does not depend on ALSA period size or browser frame rate.
+
+#[derive(Clone, Debug)]
+pub struct CorrelationMeter {
+    sample_rate: u32,
+    response_seconds: f32,
+    alpha: f64,
+    power_l: f64,
+    power_r: f64,
+    cross_power: f64,
+    value: f32,
+    negative_peak: f32,
+    reset_token: u64,
+}
+
+impl CorrelationMeter {
+    pub fn new(sample_rate: u32, response_seconds: f32, reset_token: u64) -> Self {
+        let mut meter = Self {
+            sample_rate: 0,
+            response_seconds: 0.0,
+            alpha: 1.0,
+            power_l: 0.0,
+            power_r: 0.0,
+            cross_power: 0.0,
+            value: 0.0,
+            negative_peak: 1.0,
+            reset_token,
+        };
+        meter.configure(sample_rate, response_seconds, reset_token);
+        meter
+    }
+
+    pub fn configure(&mut self, sample_rate: u32, response_seconds: f32, reset_token: u64) {
+        let sample_rate = sample_rate.max(8_000);
+        let response_seconds = normalize_response_seconds(response_seconds);
+        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();
+        }
+        if self.reset_token != reset_token {
+            self.reset_token = reset_token;
+            self.negative_peak = 1.0;
+        }
+    }
+
+    pub fn process(&mut self, left: f32, right: f32) {
+        let l = f64::from(left);
+        let r = f64::from(right);
+        self.power_l += self.alpha * (l * l - self.power_l);
+        self.power_r += self.alpha * (r * r - self.power_r);
+        self.cross_power += self.alpha * (l * r - self.cross_power);
+
+        // Below roughly -100 dBFS RMS per channel the quotient is no longer a
+        // useful phase measurement and should settle at the neutral position.
+        const MIN_POWER: f64 = 1.0e-10;
+        let denominator = (self.power_l * self.power_r).sqrt();
+        self.value = if self.power_l > MIN_POWER && self.power_r > MIN_POWER && denominator > 0.0 {
+            (self.cross_power / denominator).clamp(-1.0, 1.0) as f32
+        } else {
+            0.0
+        };
+        if self.value < self.negative_peak {
+            self.negative_peak = self.value;
+        }
+    }
+
+    pub fn value(&self) -> f32 {
+        self.value
+    }
+
+    pub fn negative_peak(&self) -> f32 {
+        self.negative_peak
+    }
+}
+
+pub fn normalize_response_seconds(value: f32) -> f32 {
+    if value.is_finite() && value >= 1.75 {
+        2.5
+    } else {
+        1.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn run_signal<F>(meter: &mut CorrelationMeter, seconds: usize, mut signal: F)
+    where
+        F: FnMut(usize) -> (f32, f32),
+    {
+        let count = meter.sample_rate as usize * seconds;
+        for index in 0..count {
+            let (left, right) = signal(index);
+            meter.process(left, right);
+        }
+    }
+
+    #[test]
+    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)] {
+            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());
+        }
+    }
+
+    #[test]
+    fn response_time_and_peak_reset_are_deterministic() {
+        let sample_rate = 48_000;
+        let mut fast = CorrelationMeter::new(sample_rate, 1.0, 0);
+        let mut slow = CorrelationMeter::new(sample_rate, 2.5, 0);
+        for index in 0..sample_rate as usize {
+            let sample = if index & 1 == 0 { 0.5 } else { -0.5 };
+            fast.process(sample, sample);
+            slow.process(sample, sample);
+        }
+        assert!(fast.value() > 0.999);
+        assert!(slow.value() > 0.999);
+        run_signal(&mut fast, 2, |index| {
+            let sample = if index & 1 == 0 { 0.5 } else { -0.5 };
+            (sample, -sample)
+        });
+        assert!(fast.negative_peak() < -0.7);
+        fast.configure(sample_rate, 1.0, 1);
+        assert_eq!(fast.negative_peak(), 1.0);
+    }
+
+    #[test]
+    fn silence_and_single_channel_are_neutral() {
+        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);
+        run_signal(&mut meter, 2, |index| {
+            let sample = if index & 1 == 0 { 0.5 } else { -0.5 };
+            (sample, 0.0)
+        });
+        assert_eq!(meter.value(), 0.0);
+    }
+}

src/main.rs

@@ -1,13 +1,19 @@
 mod audio;
 mod config;
+mod correlation;
 mod model;
+mod ppm;
 mod routes;
+mod rta;
 mod state;
 
 use std::net::SocketAddr;
 
 use anyhow::Context;
-use axum::{routing::{get, post}, Router};
+use axum::{
+    routing::{get, post},
+    Router,
+};
 use config::PhoenixConfig;
 use state::AppState;
 use tower_http::{cors::CorsLayer, trace::TraceLayer};
@@ -30,18 +36,50 @@ async fn main() -> anyhow::Result<()> {
     let app = Router::new()
         .route("/health", get(routes::health))
         .route("/api/v1/status", get(routes::status))
-        .route("/api/v1/global-config", get(routes::get_global_config).post(routes::set_global_config))
+        .route(
-        .route("/api/v1/frontend-presets", get(routes::get_frontend_presets).post(routes::set_frontend_preset))
+            "/api/v1/global-config",
-        .route("/api/v1/frontend-layouts", get(routes::get_frontend_layouts).post(routes::set_frontend_layout))
+            get(routes::get_global_config).post(routes::set_global_config),
-        .route("/api/v1/update/download", post(routes::download_online_update))
+        )
+        .route(
+            "/api/v1/frontend-presets",
+            get(routes::get_frontend_presets).post(routes::set_frontend_preset),
+        )
+        .route(
+            "/api/v1/frontend-layouts",
+            get(routes::get_frontend_layouts).post(routes::set_frontend_layout),
+        )
+        .route(
+            "/api/v1/update/download",
+            post(routes::download_online_update),
+        )
         .route("/api/v1/update/log", get(routes::get_online_update_log))
-        .route("/api/v1/update/restart", post(routes::restart_after_online_update))
+        .route(
-        .route("/api/v1/rta-config", get(routes::get_rta_config).post(routes::set_rta_config))
+            "/api/v1/update/restart",
-        .route("/api/v1/recordings/wav/start/:session_id", post(routes::start_wav_recording))
+            post(routes::restart_after_online_update),
-        .route("/api/v1/recordings/wav/stop/:session_id", post(routes::stop_wav_recording))
+        )
-        .route("/api/v1/recordings/stop/:session_id/:format", post(routes::stop_recording_with_format))
+        .route(
-        .route("/api/v1/recordings/save/:target/:filename", post(routes::save_recording_file))
+            "/api/v1/rta-config",
+            get(routes::get_rta_config).post(routes::set_rta_config),
+        )
+        .route(
+            "/api/v1/recordings/wav/start/:session_id",
+            post(routes::start_wav_recording),
+        )
+        .route(
+            "/api/v1/recordings/wav/stop/:session_id",
+            post(routes::stop_wav_recording),
+        )
+        .route(
+            "/api/v1/recordings/stop/:session_id/:format",
+            post(routes::stop_recording_with_format),
+        )
+        .route(
+            "/api/v1/recordings/save/:target/:filename",
+            post(routes::save_recording_file),
+        )
         .route("/api/v1/metrics/ws", get(routes::metrics_ws))
+        .route("/api/v1/spectro/ws", get(routes::spectro_ws))
+        .route("/api/v1/visuals/ws", get(routes::visuals_ws))
         .layer(CorsLayer::permissive())
         .layer(TraceLayer::new_for_http())
         .with_state(state);

src/model.rs

@@ -21,7 +21,6 @@ pub struct RtaFrame {
     pub engine: String,
     pub bands_avg: Vec<f32>,
     pub bands_peak: Vec<f32>,
-    pub bands: Vec<f32>,
     pub centers: Vec<f32>,
     pub freq_min: f32,
     pub freq_max: f32,
@@ -33,6 +32,7 @@ pub struct RtaFrame {
 
 #[derive(Clone, Debug, Serialize)]
 pub struct SpectroFrame {
+    pub seq: u64,
     pub bins: Vec<f32>,
     pub sample_rate: u32,
     pub fft_size: u32,
@@ -72,6 +72,9 @@ pub struct PhoenixRtaConfig {
     pub ppm_ebu_decay_db_per_s: f32,
     pub lufs_i_window_min: u32,
     pub lufs_i_norm_enabled: bool,
+    pub correlation_response_s: f32,
+    pub correlation_reset_token: u64,
+    pub xy_points: u32,
 }
 
 impl Default for PhoenixRtaConfig {
@@ -82,23 +85,26 @@ impl Default for PhoenixRtaConfig {
             mono_input: false,
             lr_fractional_delay_enabled: true,
             lr_fractional_delay_samples: 0.05,
-            bpo: "1_6".to_string(),
+            bpo: "1_3".to_string(),
             freq_range: "norm".to_string(),
             weighting: "z".to_string(),
-            order: 4,
+            order: 6,
             tau_fast: 0.12,
             tau_slow: 1.0,
             integration: "fast".to_string(),
             layout: "rtw".to_string(),
             input_offset_db_l: -5.0,
             input_offset_db_r: -5.0,
-            ppm_din_attack_ms: 5.0,
+            ppm_din_attack_ms: 10.0,
-            ppm_din_decay_db_per_s: 11.8,
+            ppm_din_decay_db_per_s: 20.0 / 1.5,
             ppm_din_fast_attack: false,
             ppm_ebu_attack_ms: 10.0,
-            ppm_ebu_decay_db_per_s: 8.6,
+            ppm_ebu_decay_db_per_s: 24.0 / 2.8,
             lufs_i_window_min: 4,
             lufs_i_norm_enabled: false,
+            correlation_response_s: 1.0,
+            correlation_reset_token: 0,
+            xy_points: 1024,
         }
     }
 }
@@ -136,6 +142,8 @@ pub struct PhoenixGlobalConfig {
     pub clock_led_color: String,
     pub header_text_color: String,
     pub rta_bar_base_color: String,
+    pub spectro_gamma: f32,
+    pub spectro_scroll_mode: f32,
     pub peak_history_scroll_mode: f32,
     pub peak_history_fill_enabled: bool,
     pub peak_history_fill_invert: bool,
@@ -175,7 +183,7 @@ impl Default for PhoenixGlobalConfig {
         Self {
             fft_size: 8192,
             input_source: InputSource::Line,
-            rta_bpo_mode: "1_6".to_string(),
+            rta_bpo_mode: "1_3".to_string(),
             input_offset_db_l: -5.0,
             input_offset_db_r: -5.0,
             mono_input: false,
@@ -184,11 +192,11 @@ impl Default for PhoenixGlobalConfig {
             al_markers_enabled: false,
             meter_bar_thin: 0.55,
             panel_dividers_enabled: true,
-            ppm_din_attack_ms: 5.0,
+            ppm_din_attack_ms: 10.0,
-            ppm_din_decay_db_per_s: 11.8,
+            ppm_din_decay_db_per_s: 20.0 / 1.5,
             ppm_din_fast_attack: false,
             ppm_ebu_attack_ms: 10.0,
-            ppm_ebu_decay_db_per_s: 8.6,
+            ppm_ebu_decay_db_per_s: 24.0 / 2.8,
             lufs_i_window_min: 4,
             lufs_i_norm_enabled: false,
             ppm_din_loudness_boxes: true,
@@ -203,6 +211,8 @@ impl Default for PhoenixGlobalConfig {
             clock_led_color: "#ff0000".to_string(),
             header_text_color: "#ffe066".to_string(),
             rta_bar_base_color: "#ffe066".to_string(),
+            spectro_gamma: 0.9,
+            spectro_scroll_mode: 1.0,
             peak_history_scroll_mode: 1.0,
             peak_history_fill_enabled: false,
             peak_history_fill_invert: false,
@@ -250,6 +260,10 @@ pub struct PhoenixGlobalConfigEnvelope {
 pub struct MeterFrame {
     pub seq: u64,
     pub timestamp_ms: u128,
+    pub sample_rate: u32,
+    pub period_size: u32,
+    pub correlation: f32,
+    pub correlation_negative_peak: f32,
     pub rms_l: f32,
     pub rms_r: f32,
     pub vu_l: f32,

src/ppm.rs

@@ -0,0 +1,342 @@
+//! Continuous quasi-peak detectors for the Phoenix DIN/EBU programme meters.
+//!
+//! The detector is deliberately independent of ALSA block boundaries.  Its two
+//! attack branches are calibrated against the 5 kHz tone-burst response in EBU
+//! Tech 3205-E.  DIN uses the RTW PortaMonitor/Peakmeter norm profile (10 ms
+//! integration, 20 dB return in 1.5 s).  The optional DIN sample mode is kept
+//! separate and must never be labelled as a standards-compliant DIN reading.
+
+#![cfg_attr(not(target_os = "linux"), allow(dead_code))]
+
+const ATTACK_FAST_TAU_S: f32 = 0.001_616_75;
+const ATTACK_SLOW_TAU_S: f32 = 0.011_369_98;
+const ATTACK_FAST_MIX: f32 = 0.818_535_6;
+const STATIC_CALIBRATION_GAIN: f32 = 1.024_6;
+const OVERSAMPLE: usize = 8;
+const INTERP_RADIUS: usize = 8;
+const INTERP_TAPS: usize = INTERP_RADIUS * 2 + 1;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum PpmStandard {
+    Din,
+    DinSample,
+    EbuTypeIib,
+}
+
+impl PpmStandard {
+    fn return_db_per_second(self) -> f32 {
+        match self {
+            Self::Din | Self::DinSample => 20.0 / 1.5,
+            Self::EbuTypeIib => 24.0 / 2.8,
+        }
+    }
+
+    fn uses_sample_attack(self) -> bool {
+        matches!(self, Self::DinSample)
+    }
+}
+
+#[derive(Clone, Copy, Debug, Default)]
+struct PpmChannel {
+    fast: f32,
+    slow: f32,
+    output: f32,
+}
+
+#[derive(Clone, Debug)]
+pub struct PpmDetector {
+    sample_rate: u32,
+    standard: PpmStandard,
+    fast_coeff: f32,
+    slow_coeff: f32,
+    release_coeff: f32,
+    interp_weights: [[f32; INTERP_TAPS]; OVERSAMPLE],
+    raw_l: [f32; INTERP_TAPS],
+    raw_r: [f32; INTERP_TAPS],
+    raw_pos: usize,
+    left: PpmChannel,
+    right: PpmChannel,
+}
+
+impl PpmDetector {
+    pub fn new(sample_rate: u32, standard: PpmStandard) -> Self {
+        let sr = sample_rate.max(8_000);
+        let detector_rate = if standard.uses_sample_attack() {
+            sr as f32
+        } else {
+            (sr * OVERSAMPLE as u32) as f32
+        };
+        let coeff = |tau_s: f32| (-1.0 / (detector_rate * tau_s)).exp();
+        let release_coeff = 10.0f32.powf(-standard.return_db_per_second() / (20.0 * detector_rate));
+        Self {
+            sample_rate: sr,
+            standard,
+            fast_coeff: coeff(ATTACK_FAST_TAU_S),
+            slow_coeff: coeff(ATTACK_SLOW_TAU_S),
+            release_coeff,
+            interp_weights: Self::create_interp_weights(),
+            raw_l: [0.0; INTERP_TAPS],
+            raw_r: [0.0; INTERP_TAPS],
+            raw_pos: 0,
+            left: PpmChannel::default(),
+            right: PpmChannel::default(),
+        }
+    }
+
+    pub fn ensure_profile(&mut self, sample_rate: u32, standard: PpmStandard) {
+        let sr = sample_rate.max(8_000);
+        if self.sample_rate != sr || self.standard != standard {
+            *self = Self::new(sr, standard);
+        }
+    }
+
+    pub fn process(&mut self, left: f32, right: f32) -> (f32, f32) {
+        if self.standard.uses_sample_attack() {
+            let l = Self::process_channel(
+                &mut self.left,
+                left.abs(),
+                self.standard,
+                self.fast_coeff,
+                self.slow_coeff,
+                self.release_coeff,
+            );
+            let r = Self::process_channel(
+                &mut self.right,
+                right.abs(),
+                self.standard,
+                self.fast_coeff,
+                self.slow_coeff,
+                self.release_coeff,
+            );
+            return (l, r);
+        }
+
+        self.raw_l[self.raw_pos] = left;
+        self.raw_r[self.raw_pos] = right;
+        self.raw_pos = (self.raw_pos + 1) % INTERP_TAPS;
+
+        let standard = self.standard;
+        let fast_coeff = self.fast_coeff;
+        let slow_coeff = self.slow_coeff;
+        let release_coeff = self.release_coeff;
+        for phase in 0..OVERSAMPLE {
+            let mut l = 0.0f32;
+            let mut r = 0.0f32;
+            for tap in 0..INTERP_TAPS {
+                let ring_index = (self.raw_pos + tap) % INTERP_TAPS;
+                let weight = self.interp_weights[phase][tap];
+                l += self.raw_l[ring_index] * weight;
+                r += self.raw_r[ring_index] * weight;
+            }
+            Self::process_channel(
+                &mut self.left,
+                l.abs(),
+                standard,
+                fast_coeff,
+                slow_coeff,
+                release_coeff,
+            );
+            Self::process_channel(
+                &mut self.right,
+                r.abs(),
+                standard,
+                fast_coeff,
+                slow_coeff,
+                release_coeff,
+            );
+        }
+        self.levels()
+    }
+
+    pub fn levels(&self) -> (f32, f32) {
+        (self.left.output, self.right.output)
+    }
+
+    fn create_interp_weights() -> [[f32; INTERP_TAPS]; OVERSAMPLE] {
+        let mut weights = [[0.0; INTERP_TAPS]; OVERSAMPLE];
+        for (phase, phase_weights) in weights.iter_mut().enumerate() {
+            let position = INTERP_RADIUS as f32 + phase as f32 / OVERSAMPLE as f32;
+            let mut sum = 0.0f32;
+            for (tap, weight) in phase_weights.iter_mut().enumerate() {
+                let distance = position - tap as f32;
+                *weight = Self::sinc(distance) * Self::sinc(distance / INTERP_RADIUS as f32);
+                sum += *weight;
+            }
+            if sum.abs() > 1.0e-9 {
+                for weight in phase_weights {
+                    *weight /= sum;
+                }
+            }
+        }
+        weights
+    }
+
+    fn sinc(value: f32) -> f32 {
+        if value.abs() < 1.0e-7 {
+            1.0
+        } else {
+            let x = std::f32::consts::PI * value;
+            x.sin() / x
+        }
+    }
+
+    fn process_channel(
+        state: &mut PpmChannel,
+        input: f32,
+        standard: PpmStandard,
+        fast_coeff: f32,
+        slow_coeff: f32,
+        release_coeff: f32,
+    ) -> f32 {
+        if standard.uses_sample_attack() {
+            state.output = input.max(state.output * release_coeff);
+            state.fast = state.output;
+            state.slow = state.output;
+            return state.output;
+        }
+
+        state.fast = if input > state.fast {
+            fast_coeff * state.fast + (1.0 - fast_coeff) * input
+        } else {
+            state.fast * release_coeff
+        };
+        state.slow = if input > state.slow {
+            slow_coeff * state.slow + (1.0 - slow_coeff) * input
+        } else {
+            state.slow * release_coeff
+        };
+
+        let attack = (ATTACK_FAST_MIX * state.fast + (1.0 - ATTACK_FAST_MIX) * state.slow)
+            * STATIC_CALIBRATION_GAIN;
+        state.output = attack.max(state.output * release_coeff);
+        state.output
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const SR: u32 = 48_000;
+
+    fn sine_sample(index: usize, frequency: f32, amplitude: f32) -> f32 {
+        let phase = 2.0 * std::f32::consts::PI * frequency * index as f32 / SR as f32;
+        phase.sin() * amplitude
+    }
+
+    fn run_tone(
+        detector: &mut PpmDetector,
+        frequency: f32,
+        amplitude: f32,
+        duration_ms: f32,
+    ) -> f32 {
+        let samples = (duration_ms * SR as f32 / 1000.0).round() as usize;
+        let mut peak = 0.0f32;
+        for index in 0..samples {
+            let value = sine_sample(index, frequency, amplitude);
+            peak = peak.max(detector.process(value, value).0);
+        }
+        // The band-limited interpolator uses eight samples of look-ahead.
+        // Silence advances its final interval without materially changing PPM return.
+        for _ in 0..INTERP_RADIUS + 1 {
+            peak = peak.max(detector.process(0.0, 0.0).0);
+        }
+        peak
+    }
+
+    fn db(value: f32) -> f32 {
+        20.0 * value.max(1.0e-12).log10()
+    }
+
+    #[test]
+    fn ebu_type_iib_matches_official_tone_burst_table() {
+        // EBU Tech 3205-E table 2, expressed relative to the continuous-tone
+        // indication: 100/10/5/1.5/0.5 ms -> 0/-2/-4/-9/-17 dB.
+        let cases = [
+            (100.0, 0.0, 0.5),
+            (10.0, -2.0, 0.5),
+            (5.0, -4.0, 0.75),
+            (1.5, -9.0, 1.0),
+            (0.5, -17.0, 2.0),
+        ];
+        let mut continuous = PpmDetector::new(SR, PpmStandard::EbuTypeIib);
+        let reference = run_tone(&mut continuous, 5_000.0, 0.5, 500.0);
+
+        for (duration_ms, expected_db, tolerance_db) in cases {
+            let mut detector = PpmDetector::new(SR, PpmStandard::EbuTypeIib);
+            let measured = run_tone(&mut detector, 5_000.0, 0.5, duration_ms);
+            let relative_db = db(measured / reference);
+            assert!(
+                (relative_db - expected_db).abs() <= tolerance_db,
+                "{duration_ms} ms: measured {relative_db:.3} dB, expected {expected_db:.3} +/- {tolerance_db:.3} dB"
+            );
+        }
+    }
+
+    #[test]
+    fn ebu_return_time_is_24_db_in_2_8_seconds() {
+        assert_return_time(PpmStandard::EbuTypeIib, 24.0, 2.8, 0.02);
+    }
+
+    #[test]
+    fn din_return_time_is_20_db_in_1_5_seconds() {
+        assert_return_time(PpmStandard::Din, 20.0, 1.5, 0.02);
+    }
+
+    #[test]
+    fn fresh_detector_does_not_bypass_attack_integration() {
+        let mut detector = PpmDetector::new(SR, PpmStandard::Din);
+        let first = detector.process(1.0, 1.0).0;
+        assert!(first < 0.02, "first sample unexpectedly reached {first}");
+    }
+
+    #[test]
+    fn polarity_is_reversible() {
+        let mut positive = PpmDetector::new(SR, PpmStandard::EbuTypeIib);
+        let mut negative = PpmDetector::new(SR, PpmStandard::EbuTypeIib);
+        for index in 0..SR as usize {
+            let value = sine_sample(index, 1_000.0, 0.5);
+            positive.process(value, value);
+            negative.process(-value, -value);
+        }
+        assert!((positive.levels().0 - negative.levels().0).abs() < 1.0e-6);
+    }
+
+    #[test]
+    fn ebu_frequency_response_is_flat_through_16_khz() {
+        let frequencies = [31.5, 1_000.0, 5_000.0, 10_000.0, 12_500.0, 16_000.0];
+        let mut reference_detector = PpmDetector::new(SR, PpmStandard::EbuTypeIib);
+        let reference = run_tone(&mut reference_detector, 1_000.0, 0.5, 1_000.0);
+        for frequency in frequencies {
+            let mut detector = PpmDetector::new(SR, PpmStandard::EbuTypeIib);
+            let measured = run_tone(&mut detector, frequency, 0.5, 1_000.0);
+            let relative_db = db(measured / reference);
+            assert!(
+                relative_db.abs() <= 0.3,
+                "{frequency} Hz: measured {relative_db:.3} dB relative to 1 kHz"
+            );
+        }
+    }
+
+    fn assert_return_time(
+        standard: PpmStandard,
+        drop_db: f32,
+        expected_seconds: f32,
+        tolerance_seconds: f32,
+    ) {
+        let mut detector = PpmDetector::new(SR, standard);
+        run_tone(&mut detector, 1_000.0, 0.5, 1_000.0);
+        let start = detector.levels().0;
+        let target = start * 10.0f32.powf(-drop_db / 20.0);
+        let mut elapsed = 0usize;
+        while detector.levels().0 > target && elapsed < SR as usize * 10 {
+            detector.process(0.0, 0.0);
+            elapsed += 1;
+        }
+        let seconds = elapsed as f32 / SR as f32;
+        assert!(
+            (seconds - expected_seconds).abs() <= tolerance_seconds,
+            "return took {seconds:.4} s, expected {expected_seconds:.4} +/- {tolerance_seconds:.4} s"
+        );
+    }
+}

src/routes.rs

@@ -1,3 +1,4 @@
+use anyhow::Context;
 use axum::{
     body::Body,
     extract::{Path, Query, Request, State, WebSocketUpgrade},
@@ -5,19 +6,19 @@ use axum::{
     response::{IntoResponse, Response},
     Json,
 };
-use anyhow::Context;
 use http_body_util::BodyExt;
 use serde::Deserialize;
 use std::{
     path::PathBuf,
     process::Stdio,
+    sync::Arc,
     time::{SystemTime, UNIX_EPOCH},
 };
 use tokio::{fs, io::AsyncWriteExt, process::Command};
 use tracing::warn;
 
 use crate::{
-    model::{PhoenixGlobalConfig, PhoenixRtaConfig},
+    model::{MeterFrame, PhoenixGlobalConfig, PhoenixRtaConfig, WaveEnvFrame},
     state::AppState,
 };
 
@@ -56,7 +57,9 @@ pub async fn get_rta_config(State(state): State<AppState>) -> Json<PhoenixRtaCon
     Json(state.rta_config().await)
 }
 
-pub async fn get_global_config(State(state): State<AppState>) -> Json<crate::model::PhoenixGlobalConfigEnvelope> {
+pub async fn get_global_config(
+    State(state): State<AppState>,
+) -> Json<crate::model::PhoenixGlobalConfigEnvelope> {
     Json(state.global_config_envelope().await)
 }
 
@@ -209,7 +212,9 @@ pub async fn download_online_update() -> Response {
         }
     };
     let log_path = build_online_update_log_path(&phoenix_root);
-    let script = phoenix_root.join("scripts").join("update_phoenix_from_zip.sh");
+    let script = phoenix_root
+        .join("scripts")
+        .join("update_phoenix_from_zip.sh");
     if !script.is_file() {
         return (
             StatusCode::INTERNAL_SERVER_ERROR,
@@ -303,7 +308,9 @@ pub async fn restart_after_online_update() -> Response {
                 .into_response();
         }
     };
-    let script = phoenix_root.join("scripts").join("restart_phoenix_services.sh");
+    let script = phoenix_root
+        .join("scripts")
+        .join("restart_phoenix_services.sh");
     if !script.is_file() {
         return (
             StatusCode::INTERNAL_SERVER_ERROR,
@@ -317,9 +324,7 @@ pub async fn restart_after_online_update() -> Response {
 
     tokio::spawn(async move {
         tokio::time::sleep(tokio::time::Duration::from_millis(750)).await;
-        let _ = stable_script_command("bash")
+        let _ = stable_script_command("bash").arg(script).spawn();
-            .arg(script)
-            .spawn();
     });
 
     (
@@ -419,6 +424,14 @@ pub async fn metrics_ws(ws: WebSocketUpgrade, State(state): State<AppState>) ->
     ws.on_upgrade(move |socket| metrics_ws_inner(socket, state))
 }
 
+pub async fn spectro_ws(ws: WebSocketUpgrade, State(state): State<AppState>) -> Response {
+    ws.on_upgrade(move |socket| spectro_ws_inner(socket, state))
+}
+
+pub async fn visuals_ws(ws: WebSocketUpgrade, State(state): State<AppState>) -> Response {
+    ws.on_upgrade(move |socket| visuals_ws_inner(socket, state))
+}
+
 pub async fn start_wav_recording(
     State(state): State<AppState>,
     Path(session_id): Path<u64>,
@@ -458,7 +471,12 @@ pub async fn stop_recording_with_format(
     stop_recording_inner(state, session_id, &format, query.bitrate_kbps).await
 }
 
-async fn stop_recording_inner(state: AppState, session_id: u64, format: &str, bitrate_kbps: Option<u32>) -> Response {
+async fn stop_recording_inner(
+    state: AppState,
+    session_id: u64,
+    format: &str,
+    bitrate_kbps: Option<u32>,
+) -> Response {
     let normalized_format = normalize_recording_format(format);
     if normalized_format.is_empty() {
         return (
@@ -474,10 +492,7 @@ async fn stop_recording_inner(state: AppState, session_id: u64, format: &str, bi
         Ok(capture) => match build_capture_bytes(normalized_format, &capture, bitrate_kbps).await {
             Ok((mime_type, payload)) => (
                 StatusCode::OK,
-                [
+                [("content-type", mime_type), ("cache-control", "no-store")],
-                    ("content-type", mime_type),
-                    ("cache-control", "no-store"),
-                ],
                 Body::from(payload),
             )
                 .into_response(),
@@ -514,7 +529,8 @@ async fn build_capture_bytes(
                 capture.channels,
                 &capture.pcm_bytes,
                 normalize_mp3_bitrate_kbps(bitrate_kbps),
-            ).await?,
+            )
+            .await?,
         )),
         "webm" => Ok((
             "audio/webm",
@@ -527,7 +543,12 @@ async fn build_capture_bytes(
     }
 }
 
-async fn encode_mp3_bytes(sample_rate: u32, channels: u16, pcm_bytes: &[u8], bitrate_kbps: u32) -> anyhow::Result<Vec<u8>> {
+async fn encode_mp3_bytes(
+    sample_rate: u32,
+    channels: u16,
+    pcm_bytes: &[u8],
+    bitrate_kbps: u32,
+) -> anyhow::Result<Vec<u8>> {
     let wav = build_wav_bytes(sample_rate, channels, pcm_bytes);
     let token = format!(
         "{}-{}-{}",
@@ -557,7 +578,11 @@ async fn encode_mp3_bytes(sample_rate: u32, channels: u16, pcm_bytes: &[u8], bit
     Ok(payload)
 }
 
-async fn try_encode_mp3_with_commands(input_path: &PathBuf, output_path: &PathBuf, bitrate_kbps: u32) -> anyhow::Result<()> {
+async fn try_encode_mp3_with_commands(
+    input_path: &PathBuf,
+    output_path: &PathBuf,
+    bitrate_kbps: u32,
+) -> anyhow::Result<()> {
     let ffmpeg = Command::new("ffmpeg")
         .arg("-y")
         .arg("-hide_banner")
@@ -602,7 +627,11 @@ async fn try_encode_mp3_with_commands(input_path: &PathBuf, output_path: &PathBu
     }
 }
 
-async fn encode_webm_bytes(sample_rate: u32, channels: u16, pcm_bytes: &[u8]) -> anyhow::Result<Vec<u8>> {
+async fn encode_webm_bytes(
+    sample_rate: u32,
+    channels: u16,
+    pcm_bytes: &[u8],
+) -> anyhow::Result<Vec<u8>> {
     let wav = build_wav_bytes(sample_rate, channels, pcm_bytes);
     let token = format!(
         "{}-{}-{}",
@@ -735,27 +764,53 @@ pub async fn save_recording_file(
     }
 }
 
-async fn read_frontend_presets(config: &crate::config::PhoenixConfig) -> anyhow::Result<serde_json::Map<String, serde_json::Value>> {
+async fn read_frontend_presets(
+    config: &crate::config::PhoenixConfig,
+) -> anyhow::Result<serde_json::Map<String, serde_json::Value>> {
     let path = config.frontend_presets_path.clone();
     let raw = match fs::read_to_string(&path).await {
         Ok(raw) => raw,
         Err(err) if err.kind() == std::io::ErrorKind::NotFound => return Ok(serde_json::Map::new()),
-        Err(err) => return Err(anyhow::anyhow!("failed to read frontend presets {} ({})", path.display(), err)),
+        Err(err) => {
+            return Err(anyhow::anyhow!(
+                "failed to read frontend presets {} ({})",
+                path.display(),
+                err
+            ))
+        }
     };
-    let parsed = serde_json::from_str::<serde_json::Value>(&raw)
+    let parsed = serde_json::from_str::<serde_json::Value>(&raw).map_err(|err| {
-        .map_err(|err| anyhow::anyhow!("failed to parse frontend presets {} ({})", path.display(), err))?;
+        anyhow::anyhow!(
+            "failed to parse frontend presets {} ({})",
+            path.display(),
+            err
+        )
+    })?;
     Ok(parsed.as_object().cloned().unwrap_or_default())
 }
 
-async fn read_frontend_layouts(config: &crate::config::PhoenixConfig) -> anyhow::Result<serde_json::Map<String, serde_json::Value>> {
+async fn read_frontend_layouts(
+    config: &crate::config::PhoenixConfig,
+) -> anyhow::Result<serde_json::Map<String, serde_json::Value>> {
     let path = config.frontend_layouts_path.clone();
     let raw = match fs::read_to_string(&path).await {
         Ok(raw) => raw,
         Err(err) if err.kind() == std::io::ErrorKind::NotFound => return Ok(serde_json::Map::new()),
-        Err(err) => return Err(anyhow::anyhow!("failed to read frontend layouts {} ({})", path.display(), err)),
+        Err(err) => {
+            return Err(anyhow::anyhow!(
+                "failed to read frontend layouts {} ({})",
+                path.display(),
+                err
+            ))
+        }
     };
-    let parsed = serde_json::from_str::<serde_json::Value>(&raw)
+    let parsed = serde_json::from_str::<serde_json::Value>(&raw).map_err(|err| {
-        .map_err(|err| anyhow::anyhow!("failed to parse frontend layouts {} ({})", path.display(), err))?;
+        anyhow::anyhow!(
+            "failed to parse frontend layouts {} ({})",
+            path.display(),
+            err
+        )
+    })?;
     Ok(parsed.as_object().cloned().unwrap_or_default())
 }
 
@@ -765,9 +820,9 @@ async fn persist_frontend_presets(
 ) -> anyhow::Result<()> {
     let path = config.frontend_presets_path.clone();
     if let Some(parent) = path.parent() {
-        fs::create_dir_all(parent)
+        fs::create_dir_all(parent).await.with_context(|| {
-            .await
+            format!("failed to create frontend preset dir {}", parent.display())
-            .with_context(|| format!("failed to create frontend preset dir {}", parent.display()))?;
+        })?;
     }
     let json = serde_json::to_vec_pretty(&serde_json::Value::Object(presets.clone()))?;
     fs::write(&path, json)
@@ -782,9 +837,9 @@ async fn persist_frontend_layouts(
 ) -> anyhow::Result<()> {
     let path = config.frontend_layouts_path.clone();
     if let Some(parent) = path.parent() {
-        fs::create_dir_all(parent)
+        fs::create_dir_all(parent).await.with_context(|| {
-            .await
+            format!("failed to create frontend layout dir {}", parent.display())
-            .with_context(|| format!("failed to create frontend layout dir {}", parent.display()))?;
+        })?;
     }
     let json = serde_json::to_vec_pretty(&serde_json::Value::Object(layouts.clone()))?;
     fs::write(&path, json)
@@ -835,9 +890,17 @@ fn normalize_frontend_layout_id(raw: &str) -> String {
 
 async fn metrics_ws_inner(mut socket: axum::extract::ws::WebSocket, state: AppState) {
     let mut rx = state.subscribe_metrics();
+    let mut ticker = tokio::time::interval(std::time::Duration::from_millis(16));
+    ticker.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Skip);
     loop {
-        match rx.recv().await {
+        ticker.tick().await;
-            Ok(frame) => {
+        let Some(mut latest) = recv_latest_meter_frame(&mut rx).await else {
+            break;
+        };
+        drain_latest_meter_frame(&mut rx, &mut latest);
+        let mut frame = (*latest).clone();
+        strip_visual_payloads(&mut frame);
+
         let payload = match serde_json::to_string(&frame) {
             Ok(payload) => payload,
             Err(err) => {
@@ -853,20 +916,244 @@ async fn metrics_ws_inner(mut socket: axum::extract::ws::WebSocket, state: AppSt
             break;
         }
     }
-            Err(err) => {
+}
-                match err {
+
-                    tokio::sync::broadcast::error::RecvError::Lagged(skipped) => {
+fn strip_visual_payloads(frame: &mut MeterFrame) {
-                        warn!("metrics channel lagged by {}; dropping stale frames", skipped);
+    // Large visual payloads have bounded binary streams of their own.
+    frame.spectro = None;
+    frame.wave_l.clear();
+    frame.wave_r.clear();
+    frame.wave_channels = 0;
+    frame.xy_l.clear();
+    frame.xy_r.clear();
+    frame.wave_env = None;
+}
+
+async fn visuals_ws_inner(mut socket: axum::extract::ws::WebSocket, state: AppState) {
+    let mut rx = state.subscribe_metrics();
+    let mut ticker = tokio::time::interval(std::time::Duration::from_millis(16));
+    ticker.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Skip);
+    loop {
+        ticker.tick().await;
+        let Some(mut latest) = recv_latest_meter_frame(&mut rx).await else {
+            return;
+        };
+        let (wave_env, xy) = drain_visual_meter_frames(&mut rx, &mut latest);
+        let mut frame = (*latest).clone();
+        frame.wave_env = wave_env;
+        if let Some((left, right)) = xy {
+            frame.xy_l = left;
+            frame.xy_r = right;
+        }
+        let Some(payload) = encode_visual_frame(&frame) else {
             continue;
-                    }
+        };
-                    tokio::sync::broadcast::error::RecvError::Closed => {
+        if socket
-                        warn!("metrics channel closed");
+            .send(axum::extract::ws::Message::Binary(payload))
-                        break;
+            .await
+            .is_err()
+        {
+            return;
         }
     }
 }
+
+async fn spectro_ws_inner(mut socket: axum::extract::ws::WebSocket, state: AppState) {
+    let mut rx = state.subscribe_metrics();
+    loop {
+        let mut latest = loop {
+            match rx.recv().await {
+                Ok(frame) => {
+                    if frame.spectro.is_some() {
+                        break frame;
                     }
                 }
+                Err(tokio::sync::broadcast::error::RecvError::Lagged(_)) => continue,
+                Err(tokio::sync::broadcast::error::RecvError::Closed) => return,
+            }
+        };
+
+        loop {
+            match rx.try_recv() {
+                Ok(frame) => {
+                    if frame.spectro.is_some() {
+                        latest = frame;
+                    }
+                }
+                Err(tokio::sync::broadcast::error::TryRecvError::Lagged(_)) => continue,
+                Err(tokio::sync::broadcast::error::TryRecvError::Empty) => break,
+                Err(tokio::sync::broadcast::error::TryRecvError::Closed) => return,
+            }
+        }
+
+        let payload = encode_spectro_frame(latest.spectro.as_ref().expect("checked above"));
+        if socket
+            .send(axum::extract::ws::Message::Binary(payload))
+            .await
+            .is_err()
+        {
+            return;
+        }
+    }
+}
+
+fn encode_spectro_frame(frame: &crate::model::SpectroFrame) -> Vec<u8> {
+    const MAGIC: u32 = 0x5058_5350; // "PXSP"
+    let count = frame.bins.len().min(u32::MAX as usize) as u32;
+    let mut output = Vec::with_capacity(20 + count as usize * 4);
+    output.extend_from_slice(&MAGIC.to_le_bytes());
+    output.extend_from_slice(&(frame.seq as u32).to_le_bytes());
+    output.extend_from_slice(&frame.sample_rate.to_le_bytes());
+    output.extend_from_slice(&frame.fft_size.to_le_bytes());
+    output.extend_from_slice(&count.to_le_bytes());
+    for value in frame.bins.iter().take(count as usize) {
+        output.extend_from_slice(&value.to_le_bytes());
+    }
+    output
+}
+
+fn encode_visual_frame(frame: &MeterFrame) -> Option<Vec<u8>> {
+    const MAGIC: u32 = 0x5058_5653; // Phoenix visual stream
+    const FLAG_XY: u16 = 1;
+    const FLAG_WAVE_ENV: u16 = 2;
+
+    let xy_count = frame
+        .xy_l
+        .len()
+        .min(frame.xy_r.len())
+        .min(u32::MAX as usize);
+    let wave = frame.wave_env.as_ref().filter(|value| {
+        matches!(value.channels, 1 | 2)
+            && value.columns > 0
+            && value.data.len()
+                == value
+                    .columns
+                    .saturating_mul(value.channels as usize)
+                    .saturating_mul(2)
+    });
+    let wave_values = wave.map(|value| value.data.len()).unwrap_or(0);
+    let mut flags = 0u16;
+    if xy_count > 0 {
+        flags |= FLAG_XY;
+    }
+    if wave_values > 0 {
+        flags |= FLAG_WAVE_ENV;
+    }
+    if flags == 0 {
+        return None;
+    }
+
+    let wave_columns = wave
+        .map(|value| value.columns)
+        .unwrap_or(0)
+        .min(u32::MAX as usize) as u32;
+    let wave_channels = wave.map(|value| value.channels).unwrap_or(0) as u16;
+    let wave_column_samples = wave
+        .map(|value| value.column_samples)
+        .unwrap_or(0)
+        .min(u32::MAX as usize) as u32;
+    let wave_sample_rate = wave.map(|value| value.sample_rate).unwrap_or(0);
+    let mut output = Vec::with_capacity(32 + xy_count * 8 + wave_values * 4);
+    output.extend_from_slice(&MAGIC.to_le_bytes());
+    output.extend_from_slice(&1u16.to_le_bytes());
+    output.extend_from_slice(&flags.to_le_bytes());
+    output.extend_from_slice(&(frame.seq as u32).to_le_bytes());
+    output.extend_from_slice(&(xy_count as u32).to_le_bytes());
+    output.extend_from_slice(&wave_columns.to_le_bytes());
+    output.extend_from_slice(&wave_channels.to_le_bytes());
+    output.extend_from_slice(&0u16.to_le_bytes());
+    output.extend_from_slice(&wave_column_samples.to_le_bytes());
+    output.extend_from_slice(&wave_sample_rate.to_le_bytes());
+    for index in 0..xy_count {
+        output.extend_from_slice(&frame.xy_l[index].to_le_bytes());
+        output.extend_from_slice(&frame.xy_r[index].to_le_bytes());
+    }
+    if let Some(wave) = wave {
+        for value in &wave.data {
+            output.extend_from_slice(&value.to_le_bytes());
+        }
+    }
+    Some(output)
+}
+
+async fn recv_latest_meter_frame(
+    rx: &mut tokio::sync::broadcast::Receiver<Arc<MeterFrame>>,
+) -> Option<Arc<MeterFrame>> {
+    loop {
+        match rx.recv().await {
+            Ok(frame) => return Some(frame),
+            Err(tokio::sync::broadcast::error::RecvError::Lagged(skipped)) => {
+                warn!("metrics channel skipped {} stale frames", skipped);
+            }
+            Err(tokio::sync::broadcast::error::RecvError::Closed) => return None,
+        }
+    }
+}
+
+fn drain_latest_meter_frame(
+    rx: &mut tokio::sync::broadcast::Receiver<Arc<MeterFrame>>,
+    latest: &mut Arc<MeterFrame>,
+) {
+    loop {
+        match rx.try_recv() {
+            Ok(newer) => *latest = newer,
+            Err(tokio::sync::broadcast::error::TryRecvError::Empty) => break,
+            Err(tokio::sync::broadcast::error::TryRecvError::Lagged(skipped)) => {
+                warn!("metrics drain skipped {} stale frames", skipped);
+            }
+            Err(tokio::sync::broadcast::error::TryRecvError::Closed) => break,
+        }
+    }
+}
+
+fn drain_visual_meter_frames(
+    rx: &mut tokio::sync::broadcast::Receiver<Arc<MeterFrame>>,
+    latest: &mut Arc<MeterFrame>,
+) -> (Option<WaveEnvFrame>, Option<(Vec<f32>, Vec<f32>)>) {
+    let mut combined_wave_env = latest.wave_env.clone();
+    let mut latest_xy = if latest.xy_l.is_empty() || latest.xy_r.is_empty() {
+        None
+    } else {
+        Some((latest.xy_l.clone(), latest.xy_r.clone()))
+    };
+
+    loop {
+        match rx.try_recv() {
+            Ok(newer) => {
+                merge_wave_env(&mut combined_wave_env, newer.wave_env.clone());
+                if !newer.xy_l.is_empty() && !newer.xy_r.is_empty() {
+                    latest_xy = Some((newer.xy_l.clone(), newer.xy_r.clone()));
+                }
+                *latest = newer;
+            }
+            Err(tokio::sync::broadcast::error::TryRecvError::Empty) => break,
+            Err(tokio::sync::broadcast::error::TryRecvError::Lagged(skipped)) => {
+                warn!("metrics drain skipped {} stale frames", skipped);
+            }
+            Err(tokio::sync::broadcast::error::TryRecvError::Closed) => break,
+        }
+    }
+
+    (combined_wave_env, latest_xy)
+}
+
+fn merge_wave_env(target: &mut Option<WaveEnvFrame>, incoming: Option<WaveEnvFrame>) {
+    let Some(mut incoming) = incoming else {
+        return;
+    };
+    let Some(current) = target.as_mut() else {
+        *target = Some(incoming);
+        return;
+    };
+    let compatible = current.channels == incoming.channels
+        && current.column_samples == incoming.column_samples
+        && current.sample_rate == incoming.sample_rate;
+    if compatible {
+        current.columns = current.columns.saturating_add(incoming.columns);
+        current.data.append(&mut incoming.data);
+    } else {
+        *current = incoming;
+    }
 }
 
 fn resolve_phoenix_root_dir() -> anyhow::Result<PathBuf> {
@@ -982,3 +1269,151 @@ async fn write_recording_body(
     tokio::fs::rename(&tmp_path, &path).await?;
     Ok(path.display().to_string())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn meter_frame() -> MeterFrame {
+        MeterFrame {
+            seq: 7,
+            timestamp_ms: 123,
+            sample_rate: 48_000,
+            period_size: 128,
+            correlation: 0.25,
+            correlation_negative_peak: -0.5,
+            rms_l: -20.0,
+            rms_r: -21.0,
+            vu_l: -20.0,
+            vu_r: -21.0,
+            tp_l: -18.0,
+            tp_r: -19.0,
+            ppm_din_l: -18.5,
+            ppm_din_r: -19.5,
+            ppm_ebu_l: -18.5,
+            ppm_ebu_r: -19.5,
+            lufs_m: None,
+            lufs_s: None,
+            lufs_i: None,
+            lra: None,
+            lufs_ml: None,
+            lufs_mr: None,
+            lufs_sl: None,
+            lufs_sr: None,
+            ppm_box_l: None,
+            ppm_box_r: None,
+            wave_l: vec![0.1, 0.2],
+            wave_r: vec![0.3, 0.4],
+            wave_channels: 2,
+            xy_l: vec![-0.5, 0.5],
+            xy_r: vec![0.25, -0.25],
+            rta: None,
+            spectro: None,
+            wave_env: Some(WaveEnvFrame {
+                data: vec![-0.5, 0.5, -0.25, 0.25],
+                columns: 2,
+                channels: 1,
+                column_samples: 5,
+                sample_rate: 48_000,
+            }),
+            global_config_rev: 0,
+            input: crate::model::InputSource::Line,
+            source: "test",
+        }
+    }
+
+    #[test]
+    fn spectro_binary_frame_has_stable_header_and_samples() {
+        let frame = crate::model::SpectroFrame {
+            seq: 42,
+            bins: vec![-80.0, -12.5, 0.0],
+            sample_rate: 48_000,
+            fft_size: 8_192,
+        };
+        let encoded = encode_spectro_frame(&frame);
+        assert_eq!(encoded.len(), 20 + frame.bins.len() * 4);
+        assert_eq!(
+            u32::from_le_bytes(encoded[0..4].try_into().unwrap()),
+            0x5058_5350
+        );
+        assert_eq!(u32::from_le_bytes(encoded[4..8].try_into().unwrap()), 42);
+        assert_eq!(
+            u32::from_le_bytes(encoded[8..12].try_into().unwrap()),
+            48_000
+        );
+        assert_eq!(
+            u32::from_le_bytes(encoded[12..16].try_into().unwrap()),
+            8_192
+        );
+        assert_eq!(u32::from_le_bytes(encoded[16..20].try_into().unwrap()), 3);
+        for (index, expected) in frame.bins.iter().enumerate() {
+            let offset = 20 + index * 4;
+            let actual = f32::from_le_bytes(encoded[offset..offset + 4].try_into().unwrap());
+            assert_eq!(actual, *expected);
+        }
+    }
+
+    #[test]
+    fn wave_envelopes_merge_without_losing_columns() {
+        let mut target = Some(WaveEnvFrame {
+            data: vec![-0.5, 0.5],
+            columns: 1,
+            channels: 1,
+            column_samples: 5,
+            sample_rate: 48_000,
+        });
+        merge_wave_env(
+            &mut target,
+            Some(WaveEnvFrame {
+                data: vec![-0.25, 0.25, -0.1, 0.1],
+                columns: 2,
+                channels: 1,
+                column_samples: 5,
+                sample_rate: 48_000,
+            }),
+        );
+        let merged = target.unwrap();
+        assert_eq!(merged.columns, 3);
+        assert_eq!(merged.data, vec![-0.5, 0.5, -0.25, 0.25, -0.1, 0.1]);
+    }
+
+    #[test]
+    fn visual_binary_contains_xy_and_wave_envelope() {
+        let frame = meter_frame();
+        let encoded = encode_visual_frame(&frame).unwrap();
+        assert_eq!(
+            u32::from_le_bytes(encoded[0..4].try_into().unwrap()),
+            0x5058_5653
+        );
+        assert_eq!(u16::from_le_bytes(encoded[4..6].try_into().unwrap()), 1);
+        assert_eq!(u16::from_le_bytes(encoded[6..8].try_into().unwrap()), 3);
+        assert_eq!(u32::from_le_bytes(encoded[8..12].try_into().unwrap()), 7);
+        assert_eq!(u32::from_le_bytes(encoded[12..16].try_into().unwrap()), 2);
+        assert_eq!(u32::from_le_bytes(encoded[16..20].try_into().unwrap()), 2);
+        assert_eq!(u16::from_le_bytes(encoded[20..22].try_into().unwrap()), 1);
+        assert_eq!(u32::from_le_bytes(encoded[24..28].try_into().unwrap()), 5);
+        assert_eq!(
+            u32::from_le_bytes(encoded[28..32].try_into().unwrap()),
+            48_000
+        );
+        assert_eq!(encoded.len(), 32 + 2 * 8 + 4 * 4);
+    }
+
+    #[test]
+    fn json_metrics_do_not_repeat_large_visual_payloads() {
+        let mut frame = meter_frame();
+        strip_visual_payloads(&mut frame);
+        let json = serde_json::to_string(&frame).unwrap();
+        assert!(!json.contains("wave_l"));
+        assert!(!json.contains("wave_r"));
+        assert!(!json.contains("xy_l"));
+        assert!(!json.contains("xy_r"));
+        assert!(!json.contains("wave_env"));
+        assert!(!json.contains("spectro"));
+        assert!(
+            json.len() < 1_000,
+            "scalar metrics JSON grew to {} bytes",
+            json.len()
+        );
+    }
+}

src/rta.rs

@@ -0,0 +1,551 @@
+//! Realtime-analyzer filter primitives.
+//!
+//! Fractional-octave bands are designed as complete Butterworth bandpasses:
+//! an analog low-pass prototype is transformed to a bandpass, pre-warped and
+//! mapped with the bilinear transform, then emitted as distinct SOS sections.
+
+pub const RTW_THIRD_OCTAVE_CENTERS: &[f32] = &[
+    20.0, 25.0, 31.5, 40.0, 50.0, 63.0, 80.0, 100.0, 125.0, 160.0, 200.0, 250.0, 315.0, 400.0,
+    500.0, 630.0, 800.0, 1_000.0, 1_250.0, 1_600.0, 2_000.0, 2_500.0, 3_150.0, 4_000.0, 5_000.0,
+    6_300.0, 8_000.0, 10_000.0, 12_500.0, 16_000.0, 20_000.0,
+];
+
+/// Maps a rounded preferred label to its exact IEC base-ten center frequency.
+pub fn exact_fractional_octave_center(nominal_hz: f32, bands_per_octave: usize) -> f32 {
+    let bpo = bands_per_octave.max(1) as f32;
+    let step = (bpo * (nominal_hz / 1_000.0).log10() / 0.3).round();
+    1_000.0 * 10.0f32.powf(0.3 * step / bpo)
+}
+
+pub fn fractional_octave_edges(center_hz: f32, bands_per_octave: usize) -> (f32, f32) {
+    let factor = 10.0f32.powf(3.0 / (20.0 * bands_per_octave.max(1) as f32));
+    (center_hz / factor, center_hz * factor)
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct BiquadCoeffs {
+    pub b0: f64,
+    pub b1: f64,
+    pub b2: f64,
+    pub a1: f64,
+    pub a2: f64,
+}
+
+#[derive(Clone, Copy, Debug)]
+struct Complex {
+    re: f64,
+    im: f64,
+}
+
+impl Complex {
+    fn new(re: f64, im: f64) -> Self {
+        Self { re, im }
+    }
+
+    fn add(self, other: Self) -> Self {
+        Self::new(self.re + other.re, self.im + other.im)
+    }
+
+    fn sub(self, other: Self) -> Self {
+        Self::new(self.re - other.re, self.im - other.im)
+    }
+
+    fn mul(self, other: Self) -> Self {
+        Self::new(
+            self.re * other.re - self.im * other.im,
+            self.re * other.im + self.im * other.re,
+        )
+    }
+
+    fn scale(self, value: f64) -> Self {
+        Self::new(self.re * value, self.im * value)
+    }
+
+    fn div(self, other: Self) -> Self {
+        let denom = other.re * other.re + other.im * other.im;
+        Self::new(
+            (self.re * other.re + self.im * other.im) / denom,
+            (self.im * other.re - self.re * other.im) / denom,
+        )
+    }
+
+    fn abs(self) -> f64 {
+        (self.re * self.re + self.im * self.im).sqrt()
+    }
+
+    fn sqrt(self) -> Self {
+        let magnitude = self.abs();
+        let re = ((magnitude + self.re) * 0.5).max(0.0).sqrt();
+        let im = ((magnitude - self.re) * 0.5)
+            .max(0.0)
+            .sqrt()
+            .copysign(self.im);
+        Self::new(re, im)
+    }
+}
+
+fn prewarp(freq_hz: f64, sample_rate: f64) -> f64 {
+    2.0 * sample_rate * (std::f64::consts::PI * freq_hz / sample_rate).tan()
+}
+
+fn bilinear_pole(pole: Complex, sample_rate: f64) -> Complex {
+    let two_fs = Complex::new(2.0 * sample_rate, 0.0);
+    two_fs.add(pole).div(two_fs.sub(pole))
+}
+
+/// Designs a 2N-order digital Butterworth bandpass from an N-order prototype.
+/// `prototype_order = 3` produces the conventional sixth-order analyzer band.
+pub fn design_fractional_octave_band(
+    center_hz: f32,
+    lower_hz: f32,
+    upper_hz: f32,
+    sample_rate: u32,
+    prototype_order: usize,
+) -> Vec<BiquadCoeffs> {
+    let fs = f64::from(sample_rate.max(8_000));
+    let nyquist = fs * 0.5;
+    let lower = f64::from(lower_hz).clamp(0.01, nyquist * 0.999_8);
+    let upper = f64::from(upper_hz).clamp(lower * 1.000_001, nyquist * 0.999_9);
+    let order = prototype_order.clamp(1, 4);
+    let omega_1 = prewarp(lower, fs);
+    let omega_2 = prewarp(upper, fs);
+    let bandwidth = omega_2 - omega_1;
+    let omega_0_sq = omega_1 * omega_2;
+    let mut positive_poles = Vec::with_capacity(order);
+
+    for index in 0..order {
+        let angle = std::f64::consts::PI * (2 * index + 1 + order) as f64 / (2 * order) as f64;
+        let prototype_pole = Complex::new(angle.cos(), angle.sin());
+        let bp = prototype_pole.scale(bandwidth);
+        let discriminant = bp.mul(bp).sub(Complex::new(4.0 * omega_0_sq, 0.0)).sqrt();
+        for root in [
+            bp.add(discriminant).scale(0.5),
+            bp.sub(discriminant).scale(0.5),
+        ] {
+            let digital = bilinear_pole(root, fs);
+            if digital.im > 1.0e-10 {
+                positive_poles.push(digital);
+            }
+        }
+    }
+
+    positive_poles.sort_by(|left, right| left.re.total_cmp(&right.re));
+    let mut sections: Vec<BiquadCoeffs> = positive_poles
+        .into_iter()
+        .map(|pole| BiquadCoeffs {
+            // Each section receives one zero at DC and one at Nyquist.
+            b0: 1.0,
+            b1: 0.0,
+            b2: -1.0,
+            a1: -2.0 * pole.re,
+            a2: pole.re * pole.re + pole.im * pole.im,
+        })
+        .collect();
+
+    if sections.is_empty() {
+        return sections;
+    }
+    let magnitude = cascade_magnitude(&sections, center_hz, sample_rate).max(1.0e-30);
+    let per_section_gain = (1.0 / magnitude).powf(1.0 / sections.len() as f64);
+    for section in &mut sections {
+        section.b0 *= per_section_gain;
+        section.b1 *= per_section_gain;
+        section.b2 *= per_section_gain;
+    }
+    sections
+}
+
+pub fn cascade_magnitude(sections: &[BiquadCoeffs], freq_hz: f32, sample_rate: u32) -> f64 {
+    let omega = 2.0 * std::f64::consts::PI * f64::from(freq_hz) / f64::from(sample_rate.max(8_000));
+    let z1 = Complex::new(omega.cos(), -omega.sin());
+    let z2 = z1.mul(z1);
+    sections.iter().fold(1.0, |magnitude, section| {
+        let numerator = Complex::new(section.b0, 0.0)
+            .add(z1.scale(section.b1))
+            .add(z2.scale(section.b2));
+        let denominator = Complex::new(1.0, 0.0)
+            .add(z1.scale(section.a1))
+            .add(z2.scale(section.a2));
+        magnitude * numerator.div(denominator).abs()
+    })
+}
+
+pub fn cascade_db(sections: &[BiquadCoeffs], freq_hz: f32, sample_rate: u32) -> f32 {
+    (20.0
+        * cascade_magnitude(sections, freq_hz, sample_rate)
+            .max(1.0e-30)
+            .log10()) as f32
+}
+
+pub fn integrate_power(
+    previous: f64,
+    block_power: f64,
+    block_samples: usize,
+    sample_rate: u32,
+    tau_seconds: f32,
+) -> f64 {
+    let dt = block_samples as f64 / f64::from(sample_rate.max(1));
+    let tau = f64::from(tau_seconds.max(0.001));
+    let alpha = 1.0 - (-dt / tau).exp();
+    previous + alpha * (block_power - previous)
+}
+
+#[derive(Clone, Copy)]
+struct StereoBiquad {
+    coeffs: BiquadCoeffs,
+    z1_l: f64,
+    z2_l: f64,
+    z1_r: f64,
+    z2_r: f64,
+}
+
+pub struct StereoCascade {
+    sections: Vec<StereoBiquad>,
+}
+
+impl StereoCascade {
+    pub fn new(coefficients: Vec<BiquadCoeffs>) -> Self {
+        Self {
+            sections: coefficients
+                .into_iter()
+                .map(|coeffs| StereoBiquad {
+                    coeffs,
+                    z1_l: 0.0,
+                    z2_l: 0.0,
+                    z1_r: 0.0,
+                    z2_r: 0.0,
+                })
+                .collect(),
+        }
+    }
+
+    pub fn process(&mut self, left: f32, right: f32) -> (f32, f32) {
+        let mut out_l = f64::from(left);
+        let mut out_r = f64::from(right);
+        for section in &mut self.sections {
+            out_l = section.process(out_l, false);
+            out_r = section.process(out_r, true);
+        }
+        (out_l as f32, out_r as f32)
+    }
+}
+
+impl StereoBiquad {
+    fn process(&mut self, input: f64, right: bool) -> f64 {
+        let (z1, z2) = if right {
+            (&mut self.z1_r, &mut self.z2_r)
+        } else {
+            (&mut self.z1_l, &mut self.z2_l)
+        };
+        let output = self.coeffs.b0 * input + *z1;
+        *z1 = self.coeffs.b1 * input - self.coeffs.a1 * output + *z2;
+        *z2 = self.coeffs.b2 * input - self.coeffs.a2 * output;
+        output
+    }
+}
+
+pub struct FrequencyWeighting {
+    mode: &'static str,
+    cascade: StereoCascade,
+}
+
+impl FrequencyWeighting {
+    pub fn new(mode: &str, sample_rate: u32) -> Self {
+        let mode = normalize_weighting(mode);
+        let cascade = StereoCascade::new(design_weighting(mode, sample_rate));
+        Self { mode, cascade }
+    }
+
+    pub fn process(&mut self, left: f32, right: f32) -> (f32, f32) {
+        if self.mode == "z" {
+            return (left, right);
+        }
+        self.cascade.process(left, right)
+    }
+}
+
+pub fn normalize_weighting(value: &str) -> &'static str {
+    match value.trim().to_ascii_lowercase().as_str() {
+        "a" => "a",
+        "c" => "c",
+        _ => "z",
+    }
+}
+
+fn mapped_real_pole(freq_hz: f64, sample_rate: f64) -> f64 {
+    let analog = prewarp(freq_hz.min(sample_rate * 0.499), sample_rate);
+    (2.0 * sample_rate - analog) / (2.0 * sample_rate + analog)
+}
+
+fn real_pole_section(zero_1: f64, zero_2: f64, pole_1: f64, pole_2: f64) -> BiquadCoeffs {
+    BiquadCoeffs {
+        b0: 1.0,
+        b1: -(zero_1 + zero_2),
+        b2: zero_1 * zero_2,
+        a1: -(pole_1 + pole_2),
+        a2: pole_1 * pole_2,
+    }
+}
+
+fn design_weighting(mode: &str, sample_rate: u32) -> Vec<BiquadCoeffs> {
+    if mode == "z" {
+        return Vec::new();
+    }
+    let fs = f64::from(sample_rate.max(8_000));
+    let p1 = mapped_real_pole(20.598_997, fs);
+    let p2 = mapped_real_pole(107.652_65, fs);
+    let p3 = mapped_real_pole(737.862_23, fs);
+    let p4 = mapped_real_pole(12_194.217, fs);
+    let mut sections = if mode == "a" {
+        vec![
+            real_pole_section(1.0, 1.0, p1, p1),
+            real_pole_section(1.0, 1.0, p2, p3),
+            real_pole_section(-1.0, -1.0, p4, p4),
+        ]
+    } else {
+        vec![
+            real_pole_section(1.0, 1.0, p1, p1),
+            real_pole_section(-1.0, -1.0, p4, p4),
+        ]
+    };
+    let magnitude = cascade_magnitude(&sections, 1_000.0, sample_rate).max(1.0e-30);
+    let gain = (1.0 / magnitude).powf(1.0 / sections.len() as f64);
+    for section in &mut sections {
+        section.b0 *= gain;
+        section.b1 *= gain;
+        section.b2 *= gain;
+    }
+    sections
+}
+
+pub fn weighting_response_db(mode: &str, freq_hz: f32, sample_rate: u32) -> f32 {
+    cascade_db(
+        &design_weighting(normalize_weighting(mode), sample_rate),
+        freq_hz,
+        sample_rate,
+    )
+}
+
+pub fn weighting_reference_db(mode: &str, freq_hz: f32) -> f32 {
+    if !freq_hz.is_finite() || freq_hz <= 0.0 {
+        return 0.0;
+    }
+    let f2 = freq_hz * freq_hz;
+    match normalize_weighting(mode) {
+        "a" => {
+            let numerator = (12_194.0f32 * 12_194.0) * f2 * f2;
+            let denominator = (f2 + 20.6f32 * 20.6)
+                * ((f2 + 107.7f32 * 107.7) * (f2 + 737.9f32 * 737.9)).sqrt()
+                * (f2 + 12_194.0f32 * 12_194.0);
+            20.0 * (numerator / denominator).max(1.0e-12).log10() + 2.0
+        }
+        "c" => {
+            let numerator = (12_194.0f32 * 12_194.0) * f2;
+            let denominator = (f2 + 20.6f32 * 20.6) * (f2 + 12_194.0f32 * 12_194.0);
+            20.0 * (numerator / denominator).max(1.0e-12).log10() + 0.06
+        }
+        _ => 0.0,
+    }
+}
+
+/// Corrects the finite-rate digital weighting filter at a band's center to
+/// the standardized A/C reference curve. This is especially important near
+/// Nyquist, where the bilinear filter necessarily bends toward zero.
+pub fn weighting_power_correction(mode: &str, freq_hz: f32, sample_rate: u32) -> f64 {
+    if normalize_weighting(mode) == "z" {
+        return 1.0;
+    }
+    let difference =
+        weighting_reference_db(mode, freq_hz) - weighting_response_db(mode, freq_hz, sample_rate);
+    10.0f64.powf(f64::from(difference) / 10.0)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn third_octave_butterworth_has_correct_center_and_edges() {
+        assert_eq!(RTW_THIRD_OCTAVE_CENTERS.len(), 31);
+        for &nominal_center in RTW_THIRD_OCTAVE_CENTERS {
+            let center = exact_fractional_octave_center(nominal_center, 3);
+            let (lower, upper) = fractional_octave_edges(center, 3);
+            let sections = design_fractional_octave_band(center, lower, upper, 48_000, 3);
+            assert_eq!(sections.len(), 3);
+            assert!(cascade_db(&sections, center, 48_000).abs() < 0.01);
+            let lower_db = cascade_db(&sections, lower, 48_000);
+            let upper_db = cascade_db(&sections, upper, 48_000);
+            assert!(
+                (lower_db + 3.0103).abs() < 0.08,
+                "{center}: lower {lower_db}"
+            );
+            assert!(
+                (upper_db + 3.0103).abs() < 0.08,
+                "{center}: upper {upper_db}"
+            );
+        }
+    }
+
+    #[test]
+    fn preferred_labels_map_to_exact_iec_centers() {
+        assert!((exact_fractional_octave_center(31.5, 3) - 31.622_776).abs() < 0.000_1);
+        assert_eq!(exact_fractional_octave_center(1_000.0, 3), 1_000.0);
+        assert!((exact_fractional_octave_center(20_000.0, 3) - 19_952.623).abs() < 0.01);
+        let center = exact_fractional_octave_center(1_250.0, 3);
+        let (lower, upper) = fractional_octave_edges(center, 3);
+        assert!(((lower * upper).sqrt() - center).abs() < 0.001);
+    }
+
+    #[test]
+    fn neighboring_third_octave_centers_are_suppressed() {
+        let factor = 2.0f32.powf(1.0 / 6.0);
+        let sections =
+            design_fractional_octave_band(1_000.0, 1_000.0 / factor, 1_000.0 * factor, 48_000, 3);
+        assert!(cascade_db(&sections, 1_000.0 * 2.0f32.powf(1.0 / 3.0), 48_000) < -18.0);
+        assert!(cascade_db(&sections, 1_000.0 * 2.0f32.powf(-1.0 / 3.0), 48_000) < -18.0);
+    }
+
+    #[test]
+    fn design_tracks_sample_rate() {
+        let factor = 2.0f32.powf(1.0 / 6.0);
+        for sample_rate in [44_100, 48_000, 96_000] {
+            let sections = design_fractional_octave_band(
+                10_000.0,
+                10_000.0 / factor,
+                10_000.0 * factor,
+                sample_rate,
+                3,
+            );
+            assert!(cascade_db(&sections, 10_000.0, sample_rate).abs() < 0.01);
+        }
+    }
+
+    #[test]
+    fn power_integration_is_block_size_independent() {
+        fn run(block_size: usize) -> f64 {
+            let sample_rate = 48_000;
+            let mut value = 0.0;
+            let mut processed = 0usize;
+            while processed < sample_rate as usize {
+                let count = block_size.min(sample_rate as usize - processed);
+                value = integrate_power(value, 1.0, count, sample_rate, 0.125);
+                processed += count;
+            }
+            value
+        }
+        let reference = run(1);
+        for block_size in [64, 128, 192, 512, 1_024] {
+            let actual = run(block_size);
+            assert!(
+                (actual - reference).abs() < 1.0e-12,
+                "block {block_size}: {actual} vs {reference}"
+            );
+        }
+    }
+
+    #[test]
+    fn weighting_is_normalized_and_directionally_correct() {
+        for mode in ["a", "c"] {
+            assert!(weighting_response_db(mode, 1_000.0, 48_000).abs() < 0.01);
+        }
+        assert!(weighting_response_db("a", 31.5, 48_000) < -35.0);
+        assert!(weighting_response_db("c", 31.5, 48_000) < -2.0);
+        assert!(weighting_response_db("a", 8_000.0, 48_000) < 0.0);
+        assert_eq!(weighting_response_db("z", 31.5, 48_000), 0.0);
+    }
+
+    #[test]
+    fn weighting_center_calibration_tracks_standard_reference_points() {
+        let a_points = [
+            (31.5, -39.5),
+            (63.0, -26.2),
+            (125.0, -16.1),
+            (1_000.0, 0.0),
+            (8_000.0, -1.1),
+            (16_000.0, -6.6),
+        ];
+        let c_points = [
+            (31.5, -3.0),
+            (63.0, -0.8),
+            (1_000.0, 0.0),
+            (8_000.0, -3.0),
+            (16_000.0, -8.5),
+        ];
+        for (freq, expected) in a_points {
+            let raw = weighting_response_db("a", freq, 48_000);
+            let correction = 10.0 * weighting_power_correction("a", freq, 48_000).log10() as f32;
+            let actual = raw + correction;
+            assert!((actual - expected).abs() < 1.0, "A {freq} Hz: {actual} dB");
+        }
+        for (freq, expected) in c_points {
+            let raw = weighting_response_db("c", freq, 48_000);
+            let correction = 10.0 * weighting_power_correction("c", freq, 48_000).log10() as f32;
+            let actual = raw + correction;
+            assert!((actual - expected).abs() < 1.0, "C {freq} Hz: {actual} dB");
+        }
+    }
+
+    #[test]
+    fn weighting_time_domain_is_finite_and_normalized() {
+        let sample_rate = 48_000;
+        for freq in [31.5, 1_000.0, 16_000.0] {
+            let mut weighting = FrequencyWeighting::new("a", sample_rate);
+            let mut input_power = 0.0f64;
+            let mut output_power = 0.0f64;
+            for index in 0..sample_rate as usize * 2 {
+                let input =
+                    (2.0 * std::f32::consts::PI * freq * index as f32 / sample_rate as f32).sin();
+                let (output, _) = weighting.process(input, input);
+                assert!(output.is_finite());
+                if index >= sample_rate as usize {
+                    input_power += f64::from(input * input);
+                    output_power += f64::from(output * output);
+                }
+            }
+            let raw_db = 10.0 * (output_power / input_power).log10();
+            let correction_db = 10.0 * weighting_power_correction("a", freq, sample_rate).log10();
+            let calibrated_db = raw_db + correction_db;
+            let expected = f64::from(weighting_reference_db("a", freq));
+            assert!(
+                (calibrated_db - expected).abs() < 0.05,
+                "A {freq} Hz: {calibrated_db} dB vs {expected} dB"
+            );
+        }
+    }
+
+    fn measured_sine_gain(filter: &mut StereoCascade, freq: f32, sample_rate: u32) -> f32 {
+        let total = sample_rate as usize * 3;
+        let settle = sample_rate as usize * 2;
+        let mut input_power = 0.0f64;
+        let mut output_power = 0.0f64;
+        for index in 0..total {
+            let phase = 2.0 * std::f32::consts::PI * freq * index as f32 / sample_rate as f32;
+            let input = phase.sin();
+            let (output, _) = filter.process(input, input);
+            if index >= settle {
+                input_power += f64::from(input * input);
+                output_power += f64::from(output * output);
+            }
+        }
+        (10.0 * (output_power / input_power).log10()) as f32
+    }
+
+    #[test]
+    fn time_domain_filter_matches_designed_response() {
+        let factor = 2.0f32.powf(1.0 / 6.0);
+        let coefficients =
+            design_fractional_octave_band(1_000.0, 1_000.0 / factor, 1_000.0 * factor, 48_000, 3);
+        let center = measured_sine_gain(
+            &mut StereoCascade::new(coefficients.clone()),
+            1_000.0,
+            48_000,
+        );
+        let edge = measured_sine_gain(
+            &mut StereoCascade::new(coefficients),
+            1_000.0 * factor,
+            48_000,
+        );
+        assert!(center.abs() < 0.02, "center gain {center}");
+        assert!((edge + 3.0103).abs() < 0.08, "edge gain {edge}");
+    }
+}

src/state.rs

@@ -2,8 +2,7 @@ use std::{
     collections::HashMap,
     sync::{
         atomic::{AtomicU64, Ordering},
-        Arc,
+        Arc, Mutex,
-        Mutex,
     },
 };
 
@@ -16,7 +15,10 @@ use tokio::{
 use crate::{
     audio::{spawn_audio_capture_worker, AudioWorkerDeps},
     config::PhoenixConfig,
-    model::{InputSource, MeterFrame, PhoenixGlobalConfig, PhoenixGlobalConfigEnvelope, PhoenixRtaConfig, ServiceStatus},
+    model::{
+        InputSource, MeterFrame, PhoenixGlobalConfig, PhoenixGlobalConfigEnvelope,
+        PhoenixRtaConfig, ServiceStatus,
+    },
 };
 
 #[derive(Clone)]
@@ -24,7 +26,8 @@ pub struct AppState {
     pub config: PhoenixConfig,
     current_input: Arc<RwLock<InputSource>>,
     seq: Arc<AtomicU64>,
-    metrics_tx: broadcast::Sender<MeterFrame>,
+    actual_sample_rate: Arc<AtomicU64>,
+    metrics_tx: broadcast::Sender<Arc<MeterFrame>>,
     restart_token: Arc<AtomicU64>,
     rta_config: Arc<RwLock<PhoenixRtaConfig>>,
     global_config: Arc<RwLock<PhoenixGlobalConfig>>,
@@ -49,7 +52,6 @@ pub(crate) struct NativeWavRecorder {
     pub pending_discontinuity: bool,
 }
 
-
 const NATIVE_RECORDING_EDGE_FADE_FRAMES: usize = 128;
 
 fn apply_native_recording_edge_fades(pcm_bytes: &mut [u8], channels: u16) {
@@ -62,7 +64,9 @@ fn apply_native_recording_edge_fades(pcm_bytes: &mut [u8], channels: u16) {
     if total_frames < 2 {
         return;
     }
-    let fade_frames = NATIVE_RECORDING_EDGE_FADE_FRAMES.min(total_frames / 2).max(1);
+    let fade_frames = NATIVE_RECORDING_EDGE_FADE_FRAMES
+        .min(total_frames / 2)
+        .max(1);
 
     for frame_idx in 0..fade_frames {
         let in_gain = (frame_idx as f32 + 1.0) / fade_frames as f32;
@@ -71,12 +75,16 @@ fn apply_native_recording_edge_fades(pcm_bytes: &mut [u8], channels: u16) {
         for ch_idx in 0..ch {
             let in_off = frame_idx * frame_size + ch_idx * 2;
             let in_sample = i16::from_le_bytes([pcm_bytes[in_off], pcm_bytes[in_off + 1]]);
-            let in_scaled = (in_sample as f32 * in_gain).round().clamp(i16::MIN as f32, i16::MAX as f32) as i16;
+            let in_scaled = (in_sample as f32 * in_gain)
+                .round()
+                .clamp(i16::MIN as f32, i16::MAX as f32) as i16;
             pcm_bytes[in_off..in_off + 2].copy_from_slice(&in_scaled.to_le_bytes());
 
             let out_off = out_frame_idx * frame_size + ch_idx * 2;
             let out_sample = i16::from_le_bytes([pcm_bytes[out_off], pcm_bytes[out_off + 1]]);
-            let out_scaled = (out_sample as f32 * out_gain).round().clamp(i16::MIN as f32, i16::MAX as f32) as i16;
+            let out_scaled = (out_sample as f32 * out_gain)
+                .round()
+                .clamp(i16::MIN as f32, i16::MAX as f32) as i16;
             pcm_bytes[out_off..out_off + 2].copy_from_slice(&out_scaled.to_le_bytes());
         }
     }
@@ -84,13 +92,18 @@ fn apply_native_recording_edge_fades(pcm_bytes: &mut [u8], channels: u16) {
 
 impl AppState {
     pub fn new(config: PhoenixConfig) -> Self {
-        let (metrics_tx, _) = broadcast::channel(512);
+        // WebSocket consumers always drain to the newest state. A small
+        // channel bounds memory and prevents seconds of stale measurements.
+        let (metrics_tx, _) = broadcast::channel(32);
         let initial_global_config = load_global_config(&config);
-        let initial_rta_config = apply_global_to_rta(config.default_rta_config(), &initial_global_config);
+        let initial_rta_config =
+            apply_global_to_rta(config.default_rta_config(), &initial_global_config);
+        let configured_sample_rate = config.sample_rate;
         Self {
             config,
             current_input: Arc::new(RwLock::new(InputSource::Line)),
             seq: Arc::new(AtomicU64::new(0)),
+            actual_sample_rate: Arc::new(AtomicU64::new(configured_sample_rate as u64)),
             metrics_tx,
             restart_token: Arc::new(AtomicU64::new(0)),
             rta_config: Arc::new(RwLock::new(initial_rta_config)),
@@ -100,7 +113,7 @@ impl AppState {
         }
     }
 
-    pub fn subscribe_metrics(&self) -> broadcast::Receiver<MeterFrame> {
+    pub fn subscribe_metrics(&self) -> broadcast::Receiver<Arc<MeterFrame>> {
         self.metrics_tx.subscribe()
     }
 
@@ -115,7 +128,10 @@ impl AppState {
             audio_engine: "alsa-direct",
             metrics_mode: "live",
             alsa_device: self.config.alsa_device(),
-            sample_rate: self.config.sample_rate,
+            sample_rate: self
+                .actual_sample_rate
+                .load(Ordering::SeqCst)
+                .min(u32::MAX as u64) as u32,
         }
     }
 
@@ -148,7 +164,7 @@ impl AppState {
             lufs_i_norm_enabled: normalized.lufs_i_norm_enabled,
             ppm_din_loudness_boxes: current.ppm_din_loudness_boxes,
             ppm_din_loudness_offset_db: current.ppm_din_loudness_offset_db,
-            xy_points: current.xy_points,
+            xy_points: normalized.xy_points,
             gonio_display_gain_db: current.gonio_display_gain_db,
             record_output_format: current.record_output_format.clone(),
             record_mp3_bitrate_kbps: current.record_mp3_bitrate_kbps,
@@ -158,6 +174,8 @@ impl AppState {
             clock_led_color: current.clock_led_color.clone(),
             header_text_color: current.header_text_color.clone(),
             rta_bar_base_color: current.rta_bar_base_color.clone(),
+            spectro_gamma: current.spectro_gamma,
+            spectro_scroll_mode: current.spectro_scroll_mode,
             peak_history_scroll_mode: current.peak_history_scroll_mode,
             peak_history_fill_enabled: current.peak_history_fill_enabled,
             peak_history_fill_invert: current.peak_history_fill_invert,
@@ -248,6 +266,7 @@ impl AppState {
             global_config_rev: self.global_config_rev.clone(),
             native_wav_recorders: self.native_wav_recorders.clone(),
             seq: self.seq.clone(),
+            actual_sample_rate: self.actual_sample_rate.clone(),
             metrics_tx: self.metrics_tx.clone(),
             restart_token: self.restart_token.clone(),
         });
@@ -264,7 +283,10 @@ impl AppState {
         guard.insert(
             session_id,
             NativeWavRecorder {
-                sample_rate: self.config.sample_rate,
+                sample_rate: self
+                    .actual_sample_rate
+                    .load(Ordering::SeqCst)
+                    .min(u32::MAX as u64) as u32,
                 channels: 2,
                 pcm_bytes: Vec::new(),
                 total_frames: 0,
@@ -334,34 +356,69 @@ fn normalize_rta_config(mut config: PhoenixRtaConfig) -> PhoenixRtaConfig {
     };
     config.integration = match config.integration.trim().to_ascii_lowercase().as_str() {
         "impulse" => "impulse".to_string(),
+        "medium" => "medium".to_string(),
         "slow" => "slow".to_string(),
+        "average" => "average".to_string(),
         "peak" => "peak".to_string(),
         _ => "fast".to_string(),
     };
     config.order = config.order.clamp(2, 8);
+    if config.order % 2 != 0 {
+        config.order = (config.order + 1).min(8);
+    }
+    if config.layout == "rtw" {
+        config.engine = "iir".to_string();
+        config.bpo = "1_3".to_string();
+        config.order = 6;
+        config.freq_range = "norm".to_string();
+    }
 
-    let tau_fast = if config.tau_fast.is_finite() { config.tau_fast } else { 0.12 };
+    let tau_fast = if config.tau_fast.is_finite() {
-    let tau_slow = if config.tau_slow.is_finite() { config.tau_slow } else { 1.0 };
+        config.tau_fast
+    } else {
+        0.12
+    };
+    let tau_slow = if config.tau_slow.is_finite() {
+        config.tau_slow
+    } else {
+        1.0
+    };
     config.tau_fast = tau_fast.clamp(0.01, 3.0);
     config.tau_slow = tau_slow.clamp(0.05, 10.0);
     if config.tau_slow < config.tau_fast {
         config.tau_slow = config.tau_fast;
     }
-    let offset_l = if config.input_offset_db_l.is_finite() { config.input_offset_db_l } else { -5.0 };
+    let offset_l = if config.input_offset_db_l.is_finite() {
-    let offset_r = if config.input_offset_db_r.is_finite() { config.input_offset_db_r } else { -5.0 };
+        config.input_offset_db_l
+    } else {
+        -5.0
+    };
+    let offset_r = if config.input_offset_db_r.is_finite() {
+        config.input_offset_db_r
+    } else {
+        -5.0
+    };
     config.input_offset_db_l = offset_l.clamp(-60.0, 20.0);
     config.input_offset_db_r = offset_r.clamp(-60.0, 20.0);
-    let din_attack_ms = if config.ppm_din_attack_ms.is_finite() { config.ppm_din_attack_ms } else { 5.0 };
+    // Standard profiles are fixed. Keeping the serialized fields preserves
-    let din_decay = if config.ppm_din_decay_db_per_s.is_finite() { config.ppm_din_decay_db_per_s } else { 20.0 / 1.7 };
+    // compatibility with older clients without allowing silent mistuning.
-    let ebu_attack_ms = if config.ppm_ebu_attack_ms.is_finite() { config.ppm_ebu_attack_ms } else { 10.0 };
+    config.ppm_din_attack_ms = 10.0;
-    let ebu_decay = if config.ppm_ebu_decay_db_per_s.is_finite() { config.ppm_ebu_decay_db_per_s } else { 24.0 / 2.8 };
+    config.ppm_din_decay_db_per_s = 20.0 / 1.5;
-    config.ppm_din_attack_ms = din_attack_ms.clamp(0.1, 100.0);
-    config.ppm_din_decay_db_per_s = din_decay.clamp(0.1, 120.0);
     config.ppm_din_fast_attack = !!config.ppm_din_fast_attack;
-    config.ppm_ebu_attack_ms = ebu_attack_ms.clamp(0.1, 100.0);
+    config.ppm_ebu_attack_ms = 10.0;
-    config.ppm_ebu_decay_db_per_s = ebu_decay.clamp(0.1, 120.0);
+    config.ppm_ebu_decay_db_per_s = 24.0 / 2.8;
     config.lufs_i_window_min = config.lufs_i_window_min.clamp(1, 10);
     config.lufs_i_norm_enabled = !!config.lufs_i_norm_enabled;
+    config.correlation_response_s =
+        crate::correlation::normalize_response_seconds(config.correlation_response_s);
+    config.xy_points = match config.xy_points {
+        128 | 256 | 512 | 1024 | 2048 => config.xy_points,
+        n if n < 192 => 128,
+        n if n < 384 => 256,
+        n if n < 768 => 512,
+        n if n < 1536 => 1024,
+        _ => 2048,
+    };
     config
 }
 
@@ -388,7 +445,10 @@ fn normalize_meter_slot(input: String, fallback: &str) -> String {
     }
 }
 
-fn normalize_global_config(mut config: PhoenixGlobalConfig, runtime: &PhoenixConfig) -> PhoenixGlobalConfig {
+fn normalize_global_config(
+    mut config: PhoenixGlobalConfig,
+    runtime: &PhoenixConfig,
+) -> PhoenixGlobalConfig {
     config.fft_size = match config.fft_size {
         2048 | 4096 | 8192 | 16384 => config.fft_size,
         n if n < 3072 => 2048,
@@ -402,8 +462,16 @@ fn normalize_global_config(mut config: PhoenixGlobalConfig, runtime: &PhoenixCon
         "1_12" => "1_12".to_string(),
         _ => "1_6".to_string(),
     };
-    let offset_l = if config.input_offset_db_l.is_finite() { config.input_offset_db_l } else { -5.0 };
+    let offset_l = if config.input_offset_db_l.is_finite() {
-    let offset_r = if config.input_offset_db_r.is_finite() { config.input_offset_db_r } else { -5.0 };
+        config.input_offset_db_l
+    } else {
+        -5.0
+    };
+    let offset_r = if config.input_offset_db_r.is_finite() {
+        config.input_offset_db_r
+    } else {
+        -5.0
+    };
     config.input_offset_db_l = offset_l.clamp(-10.0, 10.0);
     config.input_offset_db_r = offset_r.clamp(-10.0, 10.0);
     config.mono_input = !!config.mono_input;
@@ -415,22 +483,26 @@ fn normalize_global_config(mut config: PhoenixGlobalConfig, runtime: &PhoenixCon
     };
     config.lr_fractional_delay_samples = delay.clamp(-1.5, 1.5);
     config.al_markers_enabled = !!config.al_markers_enabled;
-    let thin = if config.meter_bar_thin.is_finite() { config.meter_bar_thin } else { 0.55 };
+    let thin = if config.meter_bar_thin.is_finite() {
+        config.meter_bar_thin
+    } else {
+        0.55
+    };
     config.meter_bar_thin = thin.clamp(0.35, 0.9);
     config.panel_dividers_enabled = !!config.panel_dividers_enabled;
-    let din_attack_ms = if config.ppm_din_attack_ms.is_finite() { config.ppm_din_attack_ms } else { 5.0 };
+    config.ppm_din_attack_ms = 10.0;
-    let din_decay = if config.ppm_din_decay_db_per_s.is_finite() { config.ppm_din_decay_db_per_s } else { 20.0 / 1.7 };
+    config.ppm_din_decay_db_per_s = 20.0 / 1.5;
-    let ebu_attack_ms = if config.ppm_ebu_attack_ms.is_finite() { config.ppm_ebu_attack_ms } else { 10.0 };
-    let ebu_decay = if config.ppm_ebu_decay_db_per_s.is_finite() { config.ppm_ebu_decay_db_per_s } else { 24.0 / 2.8 };
-    config.ppm_din_attack_ms = din_attack_ms.clamp(0.1, 100.0);
-    config.ppm_din_decay_db_per_s = din_decay.clamp(0.1, 120.0);
     config.ppm_din_fast_attack = !!config.ppm_din_fast_attack;
-    config.ppm_ebu_attack_ms = ebu_attack_ms.clamp(0.1, 100.0);
+    config.ppm_ebu_attack_ms = 10.0;
-    config.ppm_ebu_decay_db_per_s = ebu_decay.clamp(0.1, 120.0);
+    config.ppm_ebu_decay_db_per_s = 24.0 / 2.8;
     config.lufs_i_window_min = config.lufs_i_window_min.clamp(1, 10);
     config.lufs_i_norm_enabled = !!config.lufs_i_norm_enabled;
     config.ppm_din_loudness_boxes = !!config.ppm_din_loudness_boxes;
-    let loudness_offset = if config.ppm_din_loudness_offset_db.is_finite() { config.ppm_din_loudness_offset_db } else { 0.0 };
+    let loudness_offset = if config.ppm_din_loudness_offset_db.is_finite() {
+        config.ppm_din_loudness_offset_db
+    } else {
+        0.0
+    };
     config.ppm_din_loudness_offset_db = loudness_offset.clamp(-7.0, 7.0);
     config.xy_points = match config.xy_points {
         128 | 256 | 512 | 1024 | 2048 => config.xy_points,
@@ -440,9 +512,18 @@ fn normalize_global_config(mut config: PhoenixGlobalConfig, runtime: &PhoenixCon
         n if n < 1536 => 1024,
         _ => 2048,
     };
-    let gonio_gain = if config.gonio_display_gain_db.is_finite() { config.gonio_display_gain_db } else { -5.0 };
+    let gonio_gain = if config.gonio_display_gain_db.is_finite() {
+        config.gonio_display_gain_db
+    } else {
+        -5.0
+    };
     config.gonio_display_gain_db = gonio_gain.clamp(-35.0, 35.0);
-    config.record_output_format = match config.record_output_format.trim().to_ascii_lowercase().as_str() {
+    config.record_output_format = match config
+        .record_output_format
+        .trim()
+        .to_ascii_lowercase()
+        .as_str()
+    {
         "mp3" => "mp3".to_string(),
         "webm" => "webm".to_string(),
         _ => "wav".to_string(),
@@ -459,13 +540,39 @@ fn normalize_global_config(mut config: PhoenixGlobalConfig, runtime: &PhoenixCon
         "volumio" => "volumio".to_string(),
         _ => "analyzer".to_string(),
     };
-    let auto_gap = if config.record_auto_split_gap_sec.is_finite() { config.record_auto_split_gap_sec } else { 1.5 };
+    let auto_gap = if config.record_auto_split_gap_sec.is_finite() {
+        config.record_auto_split_gap_sec
+    } else {
+        1.5
+    };
     config.record_auto_split_gap_sec = (auto_gap.clamp(0.5, 3.0) * 2.0).round() / 2.0;
-    let auto_threshold = if config.record_auto_threshold_dbfs.is_finite() { config.record_auto_threshold_dbfs } else { -50.0 };
+    let auto_threshold = if config.record_auto_threshold_dbfs.is_finite() {
+        config.record_auto_threshold_dbfs
+    } else {
+        -50.0
+    };
     config.record_auto_threshold_dbfs = auto_threshold.clamp(-120.0, 20.0);
     config.clock_led_color = normalize_ui_color(config.clock_led_color, "#ff0000");
     config.header_text_color = normalize_ui_color(config.header_text_color, "#ffe066");
     config.rta_bar_base_color = normalize_ui_color(config.rta_bar_base_color, "#ffe066");
+    config.spectro_gamma = if config.spectro_gamma.is_finite() {
+        config.spectro_gamma.clamp(0.3, 1.2)
+    } else {
+        0.9
+    };
+    config.spectro_scroll_mode = match config.spectro_scroll_mode {
+        x if !x.is_finite() => 1.0,
+        x if (x - 0.5).abs() < f32::EPSILON => 0.5,
+        x if (x - 1.0).abs() < f32::EPSILON => 1.0,
+        x if (x - 2.0).abs() < f32::EPSILON => 2.0,
+        x if (x - 4.0).abs() < f32::EPSILON => 4.0,
+        x if (x - 6.0).abs() < f32::EPSILON => 6.0,
+        x if x < 0.75 => 0.5,
+        x if x < 1.5 => 1.0,
+        x if x < 3.0 => 2.0,
+        x if x < 5.0 => 4.0,
+        _ => 6.0,
+    };
     config.peak_history_scroll_mode = match config.peak_history_scroll_mode {
         x if !x.is_finite() => 1.0,
         x if (x - 0.5).abs() < f32::EPSILON => 0.5,
@@ -482,9 +589,18 @@ fn normalize_global_config(mut config: PhoenixGlobalConfig, runtime: &PhoenixCon
     config.peak_history_fill_enabled = !!config.peak_history_fill_enabled;
     config.peak_history_fill_invert = !!config.peak_history_fill_invert;
     config.peak_history_slot = normalize_meter_slot(config.peak_history_slot, "ppm-din");
-    let phase_gain = if config.phase_display_gain_db.is_finite() { config.phase_display_gain_db } else { 0.0 };
+    let phase_gain = if config.phase_display_gain_db.is_finite() {
+        config.phase_display_gain_db
+    } else {
+        0.0
+    };
     config.phase_display_gain_db = (phase_gain.clamp(-35.0, 35.0) / 5.0).round() * 5.0;
-    config.phase_amplitude_mode = match config.phase_amplitude_mode.trim().to_ascii_lowercase().as_str() {
+    config.phase_amplitude_mode = match config
+        .phase_amplitude_mode
+        .trim()
+        .to_ascii_lowercase()
+        .as_str()
+    {
         "ppm-din" => "ppm-din".to_string(),
         _ => "bandpass".to_string(),
     };
@@ -513,9 +629,17 @@ fn normalize_global_config(mut config: PhoenixGlobalConfig, runtime: &PhoenixCon
     config.lufs_color_s = normalize_ui_color(config.lufs_color_s, "#ff3b3b");
     config.lufs_scale_label_color = normalize_ui_color(config.lufs_scale_label_color, "#8fd3d4");
     config.screensaver_enabled = !!config.screensaver_enabled;
-    let idle = if config.screensaver_idle_min.is_finite() { config.screensaver_idle_min } else { 5.0 };
+    let idle = if config.screensaver_idle_min.is_finite() {
+        config.screensaver_idle_min
+    } else {
+        5.0
+    };
     config.screensaver_idle_min = idle.clamp(0.0, 120.0);
-    let activity = if config.screensaver_activity_db.is_finite() { config.screensaver_activity_db } else { -50.0 };
+    let activity = if config.screensaver_activity_db.is_finite() {
+        config.screensaver_activity_db
+    } else {
+        -50.0
+    };
     config.screensaver_activity_db = activity.clamp(-120.0, 0.0);
     config.screensaver_mode = match config.screensaver_mode.trim().to_ascii_lowercase().as_str() {
         "starfield" => "starfield".to_string(),
@@ -525,11 +649,18 @@ fn normalize_global_config(mut config: PhoenixGlobalConfig, runtime: &PhoenixCon
     };
     config.screensaver_led_glow = !!config.screensaver_led_glow;
     let color = config.screensaver_led_color.trim();
-    config.screensaver_led_color = if color.is_empty() { "#ff0000".to_string() } else { color.to_string() };
+    config.screensaver_led_color = if color.is_empty() {
+        "#ff0000".to_string()
+    } else {
+        color.to_string()
+    };
     config
 }
 
-fn apply_global_to_rta(mut config: PhoenixRtaConfig, global: &PhoenixGlobalConfig) -> PhoenixRtaConfig {
+fn apply_global_to_rta(
+    mut config: PhoenixRtaConfig,
+    global: &PhoenixGlobalConfig,
+) -> PhoenixRtaConfig {
     config.fft_size = global.fft_size;
     config.bpo = global.rta_bpo_mode.clone();
     config.input_offset_db_l = global.input_offset_db_l;
@@ -544,6 +675,7 @@ fn apply_global_to_rta(mut config: PhoenixRtaConfig, global: &PhoenixGlobalConfi
     config.ppm_ebu_decay_db_per_s = global.ppm_ebu_decay_db_per_s;
     config.lufs_i_window_min = global.lufs_i_window_min;
     config.lufs_i_norm_enabled = global.lufs_i_norm_enabled;
+    config.xy_points = global.xy_points;
     normalize_rta_config(config)
 }
 
@@ -558,7 +690,10 @@ fn load_global_config(runtime: &PhoenixConfig) -> PhoenixGlobalConfig {
     normalize_global_config(parsed, runtime)
 }
 
-async fn persist_global_config(runtime: &PhoenixConfig, config: &PhoenixGlobalConfig) -> anyhow::Result<()> {
+async fn persist_global_config(
+    runtime: &PhoenixConfig,
+    config: &PhoenixGlobalConfig,
+) -> anyhow::Result<()> {
     let path = runtime.global_config_path.clone();
     if let Some(parent) = path.parent() {
         fs::create_dir_all(parent)
@@ -571,3 +706,42 @@ async fn persist_global_config(runtime: &PhoenixConfig, config: &PhoenixGlobalCo
         .with_context(|| format!("failed to write Phoenix config {}", path.display()))?;
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn rtw_profile_is_always_iir_third_octave() {
+        let config = normalize_rta_config(PhoenixRtaConfig {
+            engine: "fft".to_string(),
+            bpo: "1_12".to_string(),
+            order: 2,
+            freq_range: "lf".to_string(),
+            layout: "rtw".to_string(),
+            ..PhoenixRtaConfig::default()
+        });
+        assert_eq!(config.engine, "iir");
+        assert_eq!(config.bpo, "1_3");
+        assert_eq!(config.order, 6);
+        assert_eq!(config.freq_range, "norm");
+    }
+
+    #[test]
+    fn phoenix_profile_retains_explicit_extensions() {
+        let config = normalize_rta_config(PhoenixRtaConfig {
+            engine: "fft".to_string(),
+            bpo: "1_12".to_string(),
+            order: 8,
+            freq_range: "lf".to_string(),
+            layout: "iec".to_string(),
+            integration: "medium".to_string(),
+            ..PhoenixRtaConfig::default()
+        });
+        assert_eq!(config.engine, "fft");
+        assert_eq!(config.bpo, "1_12");
+        assert_eq!(config.order, 8);
+        assert_eq!(config.freq_range, "lf");
+        assert_eq!(config.integration, "medium");
+    }
+}

www/core/audio.js

@@ -2,14 +2,26 @@
 // Wird von main.js mit `initAudio(env)` gestartet. Nutzt env.config (CONFIG) und env.meters.
 
 import { applyPhoenixGlobalConfig, buildPhoenixGlobalConfigPayload, saveConfig } from './config.js';
+import { decodePhoenixSpectroBuffer, decodePhoenixVisualsBuffer } from './binary_protocol.js';
 import { getRtwCenters } from './rtw_centers.js';
 
 // interner Zustand (pro App-Instanz)
 let phoenixSocket = null;
+let phoenixSpectroSocket = null;
+let phoenixSpectroRetryTimer = null;
+let pendingSpectroBuffer = null;
+let phoenixSpectroRaf = 0;
+let phoenixVisualsSocket = null;
+let phoenixVisualsRetryTimer = null;
+let pendingVisualsBuffer = null;
+let phoenixVisualsRaf = 0;
 let envRef = null;
 let lifecycleHandlersBound = false;
 let recoverTimer = null;
 let lastHardRecoverAt = 0;
+let pendingPhoenixFrame = null;
+let phoenixPacketRaf = 0;
+let phoenixPacketBusy = false;
 
 const RMS_RING = { L: new Float32Array(512), R: new Float32Array(512), i: 0, n: 0 };
 const WAVEFORM_RING_SECONDS = 20;
@@ -50,22 +62,22 @@ function normalizePhoenixBaseUrl(rawValue) {
   }
 }
 
-function buildPhoenixWsUrl(baseUrl) {
+function buildPhoenixWsUrl(baseUrl, pathname = '/api/v1/metrics/ws') {
   try {
     const url = new URL(baseUrl);
     url.protocol = url.protocol === 'https:' ? 'wss:' : 'ws:';
-    url.pathname = '/api/v1/metrics/ws';
+    url.pathname = pathname;
     url.search = '';
     url.hash = '';
     return url.toString();
   } catch (_) {
     const fallback = defaultPhoenixBaseUrl();
-    return fallback.replace(/^http:/i, 'ws:').replace(/^https:/i, 'wss:') + '/api/v1/metrics/ws';
+    return fallback.replace(/^http:/i, 'ws:').replace(/^https:/i, 'wss:') + pathname;
   }
 }
 
 function closePhoenixSocket() {
-  if (!phoenixSocket) return;
+  if (phoenixSocket) {
     try {
       phoenixSocket.onopen = null;
       phoenixSocket.onmessage = null;
@@ -73,7 +85,42 @@ function closePhoenixSocket() {
       phoenixSocket.onclose = null;
       phoenixSocket.close();
     } catch (_) {}
+  }
   phoenixSocket = null;
+  if (phoenixSpectroRetryTimer) clearTimeout(phoenixSpectroRetryTimer);
+  phoenixSpectroRetryTimer = null;
+  if (phoenixSpectroSocket) {
+    try {
+      phoenixSpectroSocket.onopen = null;
+      phoenixSpectroSocket.onmessage = null;
+      phoenixSpectroSocket.onerror = null;
+      phoenixSpectroSocket.onclose = null;
+      phoenixSpectroSocket.close();
+    } catch (_) {}
+  }
+  phoenixSpectroSocket = null;
+  pendingSpectroBuffer = null;
+  if (phoenixSpectroRaf) cancelAnimationFrame(phoenixSpectroRaf);
+  phoenixSpectroRaf = 0;
+  if (phoenixVisualsRetryTimer) clearTimeout(phoenixVisualsRetryTimer);
+  phoenixVisualsRetryTimer = null;
+  if (phoenixVisualsSocket) {
+    try {
+      phoenixVisualsSocket.onopen = null;
+      phoenixVisualsSocket.onmessage = null;
+      phoenixVisualsSocket.onerror = null;
+      phoenixVisualsSocket.onclose = null;
+      phoenixVisualsSocket.close();
+    } catch (_) {}
+  }
+  phoenixVisualsSocket = null;
+  pendingVisualsBuffer = null;
+  if (phoenixVisualsRaf) cancelAnimationFrame(phoenixVisualsRaf);
+  phoenixVisualsRaf = 0;
+  pendingPhoenixFrame = null;
+  if (phoenixPacketRaf) cancelAnimationFrame(phoenixPacketRaf);
+  phoenixPacketRaf = 0;
+  phoenixPacketBusy = false;
 }
 
 async function requestPhoenixRtaConfig(baseUrl, config) {
@@ -164,14 +211,20 @@ function applyRmsActivity(env, rmsL, rmsR, sampleTs) {
   if (hit) env.audio.lastSignalTs = sampleTs;
 }
 
-function copyPhoenixSpectroBins(audioState, spectro) {
+function copyPhoenixSpectroBins(audioState, spectro, frameDelta = 1) {
-  if (!audioState) return;
+  if (!audioState) return false;
-  const src = Array.isArray(spectro?.bins) ? spectro.bins : null;
+  const src = Array.isArray(spectro?.bins) || ArrayBuffer.isView(spectro?.bins)
+    ? spectro.bins
+    : null;
   if (!src || !src.length) {
     audioState.phoenixSpectroBuffer = null;
     audioState.phoenixSpectroMeta = null;
-    return;
+    return false;
   }
+  const sourceSeq = Number(spectro?.seq);
+  const previousSourceSeq = Number(audioState.phoenixSpectroSourceSeq || 0);
+  if (Number.isFinite(sourceSeq) && sourceSeq > 0
+      && previousSourceSeq > 0 && sourceSeq <= previousSourceSeq) return false;
   let target = audioState.phoenixSpectroBuffer;
   if (!(target instanceof Float32Array) || target.length !== src.length) {
     target = new Float32Array(src.length);
@@ -190,7 +243,118 @@ function copyPhoenixSpectroBins(audioState, spectro) {
     fftSize,
     frequencyBinCount: target.length,
   };
-  audioState.phoenixSpectroSeq = (audioState.phoenixSpectroSeq || 0) + 1;
+  let delta = Number.isFinite(Number(frameDelta)) ? Math.max(1, Math.floor(Number(frameDelta))) : 1;
+  if (Number.isFinite(sourceSeq) && sourceSeq > 0) {
+    if (previousSourceSeq > 0) delta = Math.max(1, Math.floor(sourceSeq - previousSourceSeq));
+    audioState.phoenixSpectroSourceSeq = sourceSeq;
+  }
+  audioState.phoenixSpectroSeq = (audioState.phoenixSpectroSeq || 0) + delta;
+  return true;
+}
+
+function openPhoenixSpectroSocket(baseUrl, env) {
+  if (phoenixSpectroSocket && (
+    phoenixSpectroSocket.readyState === WebSocket.OPEN
+    || phoenixSpectroSocket.readyState === WebSocket.CONNECTING
+  )) return;
+  const socket = new WebSocket(buildPhoenixWsUrl(baseUrl, '/api/v1/spectro/ws'));
+  socket.binaryType = 'arraybuffer';
+  phoenixSpectroSocket = socket;
+
+  socket.onmessage = (event) => {
+    if (!(event.data instanceof ArrayBuffer)) return;
+    pendingSpectroBuffer = event.data;
+    scheduleSpectroBufferPump(env);
+  };
+
+  const retry = () => {
+    if (phoenixSpectroSocket === socket) phoenixSpectroSocket = null;
+    if (!phoenixSocket || phoenixSocket.readyState !== WebSocket.OPEN) return;
+    if (phoenixSpectroRetryTimer) clearTimeout(phoenixSpectroRetryTimer);
+    phoenixSpectroRetryTimer = setTimeout(() => {
+      phoenixSpectroRetryTimer = null;
+      openPhoenixSpectroSocket(baseUrl, env);
+    }, 1000);
+  };
+  socket.onerror = retry;
+  socket.onclose = retry;
+}
+
+function scheduleSpectroBufferPump(env) {
+  if (phoenixSpectroRaf || !pendingSpectroBuffer) return;
+  phoenixSpectroRaf = requestAnimationFrame(() => {
+    phoenixSpectroRaf = 0;
+    const buffer = pendingSpectroBuffer;
+    pendingSpectroBuffer = null;
+    try {
+      const decoded = decodePhoenixSpectroBuffer(buffer);
+      if (!decoded) return;
+      if (!copyPhoenixSpectroBins(env.audio, decoded)) return;
+      env.requestRender?.('spectro');
+    } catch (err) {
+      console.warn('Phoenix spectrogram packet error:', err);
+    } finally {
+      if (pendingSpectroBuffer) scheduleSpectroBufferPump(env);
+    }
+  });
+}
+
+function openPhoenixVisualsSocket(baseUrl, env) {
+  if (phoenixVisualsSocket && (
+    phoenixVisualsSocket.readyState === WebSocket.OPEN
+    || phoenixVisualsSocket.readyState === WebSocket.CONNECTING
+  )) return;
+  const socket = new WebSocket(buildPhoenixWsUrl(baseUrl, '/api/v1/visuals/ws'));
+  socket.binaryType = 'arraybuffer';
+  phoenixVisualsSocket = socket;
+  socket.onmessage = (event) => {
+    if (!(event.data instanceof ArrayBuffer)) return;
+    pendingVisualsBuffer = event.data;
+    scheduleVisualsBufferPump(env);
+  };
+  const retry = () => {
+    if (phoenixVisualsSocket === socket) phoenixVisualsSocket = null;
+    if (!phoenixSocket || phoenixSocket.readyState !== WebSocket.OPEN) return;
+    if (phoenixVisualsRetryTimer) clearTimeout(phoenixVisualsRetryTimer);
+    phoenixVisualsRetryTimer = setTimeout(() => {
+      phoenixVisualsRetryTimer = null;
+      openPhoenixVisualsSocket(baseUrl, env);
+    }, 1000);
+  };
+  socket.onerror = retry;
+  socket.onclose = retry;
+}
+
+function scheduleVisualsBufferPump(env) {
+  if (phoenixVisualsRaf || !pendingVisualsBuffer) return;
+  phoenixVisualsRaf = requestAnimationFrame(() => {
+    phoenixVisualsRaf = 0;
+    const buffer = pendingVisualsBuffer;
+    pendingVisualsBuffer = null;
+    try {
+      applyVisualsBuffer(env, buffer);
+    } catch (err) {
+      console.warn('Phoenix visual packet error:', err);
+    } finally {
+      if (pendingVisualsBuffer) scheduleVisualsBufferPump(env);
+    }
+  });
+}
+
+function applyVisualsBuffer(env, buffer) {
+  const decoded = decodePhoenixVisualsBuffer(buffer);
+  if (!decoded) return;
+  const { seq, left, right, wave } = decoded;
+  const previousSeq = Number(env.audio?.phoenixVisualsSeq || 0);
+  if (previousSeq > 0 && seq <= previousSeq) return;
+  if (left && right) {
+    env.audio.xyL = left;
+    env.audio.xyR = right;
+    env.audio.xySeq = seq;
+  }
+  if (wave) updateWaveformEnvelopeStore(env.audio, wave);
+  env.audio.phoenixVisualsSeq = seq;
+  env.requestRender?.('visuals');
 }
 
 async function updateActiveMeters(env, packet, CONFIG) {
@@ -230,21 +394,33 @@ async function syncPhoenixGlobalConfig(env, revision) {
 async function applyIncomingAudioPacket(env, packet, CONFIG, sampleTs = performance.now()) {
   const d = packet || {};
   if (!env?.audio) return;
+  const seq = Number(d.seq);
+  const previousSeq = Number(env.audio.phoenixMetricsSeq || 0);
+  if (Number.isFinite(seq) && seq > 0 && previousSeq > 0 && seq <= previousSeq) return;
+  if (Number.isFinite(seq) && seq > 0) env.audio.phoenixMetricsSeq = seq;
   env.requestRender?.('audio');
   env.audio.lastSampleTs = sampleTs;
   env.audio.alive = true;
+  if (Number.isFinite(Number(d.sampleRate)) && Number(d.sampleRate) > 0) {
+    env.audio.sampleRate = Number(d.sampleRate);
+    env.audio.nyq = Number(d.sampleRate) / 2;
+  }
   if (d.xyL && d.xyR) {
     env.audio.xyL = d.xyL;
     env.audio.xyR = d.xyR;
     env.audio.xySeq = Number.isFinite(d.seq) ? d.seq : (env.audio.xySeq || 0);
   }
+  if (typeof d.correlation === 'number') env.audio.correlation = d.correlation;
+  if (typeof d.correlationNegativePeak === 'number') {
+    env.audio.correlationNegativePeak = d.correlationNegativePeak;
+  }
   if (d.waveL && env.audio.pushWaveSamples) {
     const channelCount = d.waveChannels || (d.waveR ? 2 : 1);
     env.audio.sampleRate = d.sampleRate || env.audio.sampleRate || 48000;
     env.audio.pushWaveSamples(d.waveL, d.waveR || null, channelCount, d.sampleRate);
   }
   if (d.rta) env.audio.rtaData = d.rta;
-  if (d.spectro) copyPhoenixSpectroBins(env.audio, d.spectro);
+  if (d.spectro) copyPhoenixSpectroBins(env.audio, d.spectro, d.spectroFrameDelta);
   if (typeof d.ppmDinL === 'number') env.audio.ppmDinL = d.ppmDinL;
   if (typeof d.ppmDinR === 'number') env.audio.ppmDinR = d.ppmDinR;
   if (typeof d.ppmEbuL === 'number') env.audio.ppmEbuL = d.ppmEbuL;
@@ -294,6 +470,8 @@ function buildPhoenixMeterPacket(frame) {
   const lufsSR = Number(frame?.lufs_sr);
   const ppmBoxL = Number(frame?.ppm_box_l);
   const ppmBoxR = Number(frame?.ppm_box_r);
+  const correlation = Number(frame?.correlation);
+  const correlationNegativePeak = Number(frame?.correlation_negative_peak);
   const xyL = Array.isArray(frame?.xy_l) ? frame.xy_l : null;
   const xyR = Array.isArray(frame?.xy_r) ? frame.xy_r : null;
   const waveL = Array.isArray(frame?.wave_l) && frame.wave_l.length ? frame.wave_l : null;
@@ -302,7 +480,11 @@ function buildPhoenixMeterPacket(frame) {
   const spectro = frame?.spectro && typeof frame.spectro === 'object' ? frame.spectro : null;
   const waveEnv = frame?.wave_env && typeof frame.wave_env === 'object' ? frame.wave_env : null;
   return {
-    sampleRate: 48000,
+    sampleRate: Number.isFinite(Number(frame?.sample_rate)) ? Number(frame.sample_rate) : 48000,
+    correlation: Number.isFinite(correlation) ? Math.max(-1, Math.min(1, correlation)) : 0,
+    correlationNegativePeak: Number.isFinite(correlationNegativePeak)
+      ? Math.max(-1, Math.min(1, correlationNegativePeak))
+      : 0,
     rmsL: Number.isFinite(rmsL) ? rmsL : -120,
     rmsR: Number.isFinite(rmsR) ? rmsR : -120,
     tpL: Number.isFinite(tpL) ? tpL : -120,
@@ -344,10 +526,14 @@ function buildPhoenixMeterPacket(frame) {
       sampleRate: Number.isFinite(Number(rta?.sample_rate)) ? Number(rta.sample_rate) : 48000,
     } : null,
     spectro: spectro ? {
+      seq: Number.isFinite(Number(spectro?.seq)) ? Number(spectro.seq) : 0,
       bins: Array.isArray(spectro?.bins) ? spectro.bins : [],
       sampleRate: Number.isFinite(Number(spectro?.sample_rate)) ? Number(spectro.sample_rate) : 48000,
       fftSize: Number.isFinite(Number(spectro?.fft_size)) ? Number(spectro.fft_size) : 4096,
     } : null,
+    spectroFrameDelta: Number.isFinite(Number(frame?.__spectro_frame_delta))
+      ? Math.max(1, Math.floor(Number(frame.__spectro_frame_delta)))
+      : 1,
     waveEnv: waveEnv ? {
       data: Array.isArray(waveEnv?.data) ? waveEnv.data : [],
       columns: Number.isFinite(Number(waveEnv?.columns)) ? Number(waveEnv.columns) : 0,
@@ -363,6 +549,57 @@ function buildPhoenixMeterPacket(frame) {
   };
 }
 
+function mergePendingPhoenixFrame(previous, next) {
+  if (!next) return previous;
+  const previousSeq = Number(previous?.seq || 0);
+  const nextSeq = Number(next?.seq || 0);
+  if (previous && previousSeq > 0 && nextSeq > 0 && nextSeq <= previousSeq) return previous;
+  if (!previous) {
+    if (next?.spectro) next.__spectro_frame_delta = 1;
+    return next;
+  }
+  const merged = next;
+  if (!merged.wave_env && previous.wave_env) merged.wave_env = previous.wave_env;
+  if ((!merged.xy_l || !merged.xy_l.length) && previous.xy_l?.length) {
+    merged.xy_l = previous.xy_l;
+    merged.xy_r = previous.xy_r;
+  }
+  if (!merged.rta && previous.rta) merged.rta = previous.rta;
+  const previousSpectroCount = Math.max(0, Number(previous.__spectro_frame_delta) || 0);
+  if (merged.spectro) {
+    merged.__spectro_frame_delta = previousSpectroCount + 1;
+  } else if (previous.spectro) {
+    merged.spectro = previous.spectro;
+    merged.__spectro_frame_delta = Math.max(1, previousSpectroCount);
+  }
+  return merged;
+}
+
+function schedulePhoenixPacketPump(env, CONFIG) {
+  if (phoenixPacketRaf || phoenixPacketBusy || !pendingPhoenixFrame) return;
+  phoenixPacketRaf = requestAnimationFrame(async () => {
+    phoenixPacketRaf = 0;
+    const frame = pendingPhoenixFrame;
+    pendingPhoenixFrame = null;
+    if (!frame) return;
+    phoenixPacketBusy = true;
+    try {
+      const packet = buildPhoenixMeterPacket(frame);
+      await applyIncomingAudioPacket(env, packet, CONFIG, performance.now());
+    } catch (err) {
+      console.warn('Phoenix packet error:', err);
+    } finally {
+      phoenixPacketBusy = false;
+      if (pendingPhoenixFrame) schedulePhoenixPacketPump(env, CONFIG);
+    }
+  });
+}
+
+function enqueuePhoenixFrame(env, CONFIG, frame) {
+  pendingPhoenixFrame = mergePendingPhoenixFrame(pendingPhoenixFrame, frame);
+  schedulePhoenixPacketPump(env, CONFIG);
+}
+
 function bindLifecycleHandlers() {
   if (lifecycleHandlersBound) return;
 
@@ -625,33 +862,39 @@ function updateWaveformEnvelopeStore(audioState, payload) {
   appendWaveformEnvelope(audioState.waveEnvStore, payload);
 }
 
-function buildRtaRuntimeConfig(CONFIG = {}) {
+export function buildRtaRuntimeConfig(CONFIG = {}) {
-  const bpoMode = CONFIG.RTA_BPO_MODE || '1_6';
+  const bpoMode = CONFIG.RTA_BPO_MODE || '1_3';
   const layout = CONFIG.RTA_BAR_LAYOUT === 'rtw' ? 'rtw' : 'iec';
-  const runtimeBpoMode = layout === 'rtw' ? '1_12' : bpoMode;
+  const rtwProfile = layout === 'rtw';
+  const runtimeBpoMode = rtwProfile ? '1_3' : bpoMode;
   return {
-    engine: CONFIG.RTA_ENGINE || 'fft',
+    engine: rtwProfile ? 'iir' : (CONFIG.RTA_ENGINE || 'iir'),
     fftSize: CONFIG.FFT_SIZE || 4096,
     monoInput: !!CONFIG.MONO_INPUT,
     lrFractionalDelayEnabled: !!CONFIG.LR_FRACTIONAL_DELAY_ENABLED,
     lrFractionalDelaySamples: Number.isFinite(CONFIG.LR_FRACTIONAL_DELAY_SAMPLES) ? CONFIG.LR_FRACTIONAL_DELAY_SAMPLES : 0,
     bpo: runtimeBpoMode,
-    freqRange: CONFIG.RTA_FREQ_RANGE || 'norm',
+    freqRange: rtwProfile ? 'norm' : (CONFIG.RTA_FREQ_RANGE || 'norm'),
     weighting: CONFIG.RTA_WEIGHTING || 'z',
-    order: CONFIG.RTA_IIR_ORDER || 4,
+    order: rtwProfile ? 6 : (CONFIG.RTA_IIR_ORDER || 6),
     tauFast: CONFIG.RTA_IIR_TAU_FAST || 0.12,
     tauSlow: CONFIG.RTA_IIR_TAU_SLOW || 1.0,
     integration: CONFIG.RTA_INTEGRATION || 'fast',
     layout,
     inputOffsetDbL: Number.isFinite(CONFIG.INPUT_OFFSET_DB_L) ? CONFIG.INPUT_OFFSET_DB_L : -5,
     inputOffsetDbR: Number.isFinite(CONFIG.INPUT_OFFSET_DB_R) ? CONFIG.INPUT_OFFSET_DB_R : -5,
-    ppmDinAttackMs: Number.isFinite(CONFIG.PPM_DIN_ATTACK_MS) ? CONFIG.PPM_DIN_ATTACK_MS : 5,
+    ppmDinAttackMs: 10,
-    ppmDinDecayDbPerS: Number.isFinite(CONFIG.PPM_DIN_DECAY_DB_PER_S) ? CONFIG.PPM_DIN_DECAY_DB_PER_S : (20 / 1.7),
+    ppmDinDecayDbPerS: 20 / 1.5,
     ppmDinFastAttack: !!CONFIG.PPM_DIN_FAST_ATTACK,
-    ppmEbuAttackMs: Number.isFinite(CONFIG.PPM_EBU_ATTACK_MS) ? CONFIG.PPM_EBU_ATTACK_MS : 10,
+    ppmEbuAttackMs: 10,
-    ppmEbuDecayDbPerS: Number.isFinite(CONFIG.PPM_EBU_DECAY_DB_PER_S) ? CONFIG.PPM_EBU_DECAY_DB_PER_S : (24 / 2.8),
+    ppmEbuDecayDbPerS: 24 / 2.8,
     lufsIWindowMin: Number.isFinite(CONFIG.LUFS_I_WINDOW_MIN) ? CONFIG.LUFS_I_WINDOW_MIN : 4,
     lufsINormEnabled: !!CONFIG.LUFS_I_NORM_ENABLED,
+    correlationResponseS: Number(CONFIG.CORR_RESPONSE_S) >= 1.75 ? 2.5 : 1.0,
+    correlationResetToken: Math.max(0, Math.floor(Number(CONFIG.CORR_RESET_TOKEN) || 0)),
+    xyPoints: [128, 256, 512, 1024, 2048].includes(Number(CONFIG.XY_POINTS))
+      ? Number(CONFIG.XY_POINTS)
+      : 1024,
     rtwCenters: layout === 'rtw' ? getRtwCenters(runtimeBpoMode) : null,
   };
 }
@@ -700,6 +943,9 @@ async function initPhoenixAudio(env) {
   env.audio.phoenixSpectroScratch = null;
   env.audio.phoenixSpectroMeta = null;
   env.audio.phoenixSpectroSeq = 0;
+  env.audio.phoenixSpectroSourceSeq = 0;
+  env.audio.phoenixVisualsSeq = 0;
+  env.audio.phoenixMetricsSeq = 0;
   env.audio.rmsDb = { L: -120, R: -120, mono: -120 };
 
   const phoenixAnalyser = {
@@ -852,16 +1098,15 @@ async function initPhoenixAudio(env) {
     };
 
     socket.onopen = () => {
+      openPhoenixSpectroSocket(baseUrl, env);
+      openPhoenixVisualsSocket(baseUrl, env);
       finish(true);
     };
 
     socket.onmessage = (event) => {
       try {
         const frame = JSON.parse(event.data);
-        const packet = buildPhoenixMeterPacket(frame);
+        enqueuePhoenixFrame(env, CONFIG, frame);
-        applyIncomingAudioPacket(env, packet, CONFIG, performance.now()).catch((err) => {
-          console.warn('Phoenix packet error:', err);
-        });
       } catch (err) {
         console.warn('Phoenix metrics parse error:', err);
       }

www/core/binary_protocol.js

@@ -0,0 +1,68 @@
+// Phoenix binary WebSocket packet decoders. Keep this module dependency-free so
+// protocol compatibility can be tested without a browser.
+
+export function decodePhoenixSpectroBuffer(buffer) {
+  if (!(buffer instanceof ArrayBuffer) || buffer.byteLength < 20) return null;
+  const view = new DataView(buffer);
+  if (view.getUint32(0, true) !== 0x50585350) return null;
+  const seq = view.getUint32(4, true);
+  const sampleRate = view.getUint32(8, true);
+  const fftSize = view.getUint32(12, true);
+  const count = view.getUint32(16, true);
+  if (count < 1 || buffer.byteLength !== 20 + count * 4) return null;
+  return {
+    seq,
+    sampleRate,
+    fftSize,
+    bins: new Float32Array(buffer, 20, count),
+  };
+}
+
+export function decodePhoenixVisualsBuffer(buffer) {
+  if (!(buffer instanceof ArrayBuffer) || buffer.byteLength < 32) return null;
+  const view = new DataView(buffer);
+  if (view.getUint32(0, true) !== 0x50585653 || view.getUint16(4, true) !== 1) return null;
+  const flags = view.getUint16(6, true);
+  const seq = view.getUint32(8, true);
+  const xyCount = view.getUint32(12, true);
+  const waveColumns = view.getUint32(16, true);
+  const waveChannels = view.getUint16(20, true);
+  const waveColumnSamples = view.getUint32(24, true);
+  const waveSampleRate = view.getUint32(28, true);
+  if (waveChannels > 2) return null;
+  const xyBytes = xyCount * 8;
+  const waveValues = waveColumns * waveChannels * 2;
+  const expectedBytes = 32 + xyBytes + waveValues * 4;
+  if (!Number.isSafeInteger(expectedBytes) || buffer.byteLength !== expectedBytes) return null;
+
+  let offset = 32;
+  let left = null;
+  let right = null;
+  if ((flags & 1) && xyCount > 0) {
+    left = new Float32Array(xyCount);
+    right = new Float32Array(xyCount);
+    for (let index = 0; index < xyCount; index++) {
+      left[index] = view.getFloat32(offset, true);
+      right[index] = view.getFloat32(offset + 4, true);
+      offset += 8;
+    }
+  } else {
+    offset += xyBytes;
+  }
+
+  let wave = null;
+  if ((flags & 2) && waveValues > 0 && (waveChannels === 1 || waveChannels === 2)) {
+    const data = new Float32Array(waveValues);
+    for (let index = 0; index < waveValues; index++) {
+      data[index] = view.getFloat32(offset + index * 4, true);
+    }
+    wave = {
+      data,
+      columns: waveColumns,
+      channels: waveChannels,
+      columnSamples: waveColumnSamples,
+      sampleRate: waveSampleRate,
+    };
+  }
+  return { seq, left, right, wave };
+}

www/core/config.js

@@ -51,20 +51,20 @@ const CONFIG = {
   REALTIME_BAR_DECAY_DB_PER_S: 20,
   RTA_ENGINE: 'iir',             // 'fft' | 'iir'
   RTA_FREQ_RANGE: 'norm',        // 'norm' | 'lf'
-  RTA_BPO_MODE: '1_6',
+  RTA_BPO_MODE: '1_3',
   RTA_WEIGHTING: 'z',            // 'z' | 'a' | 'c'
   RTA_DISPLAY_GAIN_FFT_DB: 20,
   RTA_DISPLAY_GAIN_IIR_DB: 20,
   RTA_BAR_LAYOUT: 'rtw',         // 'iec' | 'rtw'
   RTA_BAR_BASE_COLOR: '#ffe066',
   HEADER_TEXT_COLOR: '#ffe066',
-  RTA_INTEGRATION: 'fast',       // 'impulse' | 'fast' | 'slow' | 'peak'
+  RTA_INTEGRATION: 'fast',       // 'impulse' | 'fast' | 'medium' | 'slow' | 'average' | 'peak'
   RTA_BALLISTICS_MODE: 'average', // 'average' | 'peak' | 'both'
   RTA_PEAK_HOLD_MODE: 'auto',    // 'off' | 'auto' | 'manual'
-  RTA_PEAK_HOLD_SEC: 2,
+  RTA_PEAK_HOLD_SEC: 2.5,
   RTA_PEAK_DECAY_DB_PER_S: 20,
   RTA_DISPLAY_HOLD_SEC: 0,
-  RTA_IIR_ORDER: 4,
+  RTA_IIR_ORDER: 6,
   RTA_IIR_TAU_FAST: 0.12,
   RTA_IIR_TAU_SLOW: 1.0,
   SPECTRO_GAMMA: 0.4,
@@ -156,20 +156,19 @@ const CONFIG = {
   PPM_DIN_TOP: +5,
   PPM_DIN_BOTTOM: -50,
   PPM_DIN_RED_START: 0,
-  // DIN PPM attack and decay times: 5 ms integration and 20 dB in 1.7 s
+  // Fixed RTW/DIN profile: 10 ms integration and 20 dB return in 1.5 s.
-  // (≈11.8 dB/s) return, per IEC 60268‑10 Type I.
+  PPM_DIN_ATTACK_MS: 10,
-  PPM_DIN_ATTACK_MS: 5,
   // Non-normative: when enabled, PPM DIN attack becomes instant (no integration).
   // Useful to compensate perceived meter lag caused by device / pipeline latency.
   PPM_DIN_FAST_ATTACK: false,
-  PPM_DIN_DECAY_DB_PER_S: 11.8,
+  PPM_DIN_DECAY_DB_PER_S: 20 / 1.5,
   // Hold time for DIN PPM: verlängert auf 1000 ms (1 s), damit der Peak‑Hold
   // auch bei kurzen Transienten deutlich sichtbar bleibt.  Gemäß
   // Rundfunkpraxis werden Peak‑Hold‑Striche häufig 1–2 Sekunden gehalten.
   PPM_DIN_HOLD_MS: 1000,
   // Decay rate for the DIN PPM hold.  When the held peak decays, it uses
-  // the same slope as the main meter (≈11.8 dB/s).
+  // the same slope as the main meter (≈13.33 dB/s).
-  PPM_DIN_HOLD_DECAY_DB_PER_S: 11.8,
+  PPM_DIN_HOLD_DECAY_DB_PER_S: 20 / 1.5,
 
   // Offsets für die PPM-Meter (DIN/EBU-spezifisch). Die EBU/DIN Offsets
   // ersetzen den früheren globalen PPM_OFFSET.
@@ -178,16 +177,18 @@ const CONFIG = {
   PPM_REF_DBFS_PEAK_FOR_0_DBU: -15.0,
 
   // Ballistic parameters for the EBU PPM (Type IIb).  Attack ~10 ms and
-  // decay 24 dB in 2.8 s (≈8.6 dB/s), per IEC 60268‑10 Type II.  A short
+  // decay 24 dB in 2.8 s (≈8.57 dB/s), per EBU Tech 3205-E Type IIb. A short
   // peak-hold (~750 ms) helps visualise transients.  Hold decay matches
   // the main decay rate.
   PPM_EBU_ATTACK_MS: 10,
-  PPM_EBU_DECAY_DB_PER_S: 8.6,
+  PPM_EBU_DECAY_DB_PER_S: 24 / 2.8,
   PPM_EBU_HOLD_MS: 750,
-  PPM_EBU_HOLD_DECAY_DB_PER_S: 8.6,
+  PPM_EBU_HOLD_DECAY_DB_PER_S: 24 / 2.8,
   CORR_SMOOTH: 0.85,
   CORR_ZERO_ON_SILENCE: false,
   CORR_SILENCE_THRESHOLD_RMS_DBFS: -75,
+  CORR_RESPONSE_S: 1.0,
+  CORR_RESET_TOKEN: 0,
   XY_POINTS: 1024,
   XY_STYLE: 'lines',
   XY_SILENCE_GATE_ENABLED: true,
@@ -198,6 +199,7 @@ const CONFIG = {
   GONIO_MANUAL_GAIN_DB: -5,
   GONIO_AGC_ENABLED: false,
   GONIO_LINE_FADE_MS: 50,
+  GONIO_PERSISTENCE_MODE: 'fast',
   PHASE_DISPLAY_GAIN_DB: 0,
   PHASE_AGC_ENABLED: false,
   PHASE_TRAIL_ENABLED: true,
@@ -599,6 +601,8 @@ const PHOENIX_GLOBAL_OPTION_KEYS = Object.freeze([
   'CLOCK_LED_COLOR',
   'HEADER_TEXT_COLOR',
   'RTA_BAR_BASE_COLOR',
+  'SPECTRO_GAMMA',
+  'SPECTRO_SCROLL_MODE',
   'PEAK_HISTORY_SCROLL_MODE',
   'PEAK_HISTORY_FILL_ENABLED',
   'PEAK_HISTORY_FILL_INVERT',
@@ -774,6 +778,14 @@ function loadConfig(opts = {}) {
     if (typeof saved.PPM_DIN_DECAY_DB_PER_S === 'number') CONFIG.PPM_DIN_DECAY_DB_PER_S = saved.PPM_DIN_DECAY_DB_PER_S;
     if (typeof saved.PPM_DIN_HOLD_MS === 'number') CONFIG.PPM_DIN_HOLD_MS = saved.PPM_DIN_HOLD_MS;
     if (CONFIG.RTA_BAR_LAYOUT === 'classic') CONFIG.RTA_BAR_LAYOUT = 'rtw';
+    if (CONFIG.RTA_BAR_LAYOUT === 'rtw') {
+      CONFIG.RTA_ENGINE = 'iir';
+      CONFIG.RTA_BPO_MODE = '1_3';
+      CONFIG.RTA_IIR_ORDER = 6;
+      CONFIG.RTA_FREQ_RANGE = 'norm';
+      const hold = Number(CONFIG.RTA_PEAK_HOLD_SEC);
+      CONFIG.RTA_PEAK_HOLD_SEC = hold >= 3.25 ? 4.0 : 2.5;
+    }
     if (!Number.isFinite(CONFIG.DBFS_TOP)) CONFIG.DBFS_TOP = CONFIG_DEFAULTS.DBFS_TOP;
     if (!Number.isFinite(CONFIG.DBFS_BOTTOM)) CONFIG.DBFS_BOTTOM = CONFIG_DEFAULTS.DBFS_BOTTOM;
     // Clamp to sensible bounds while keeping the user-selected display range.
@@ -827,6 +839,14 @@ function loadConfig(opts = {}) {
     CONFIG.LR_FRACTIONAL_DELAY_SAMPLES = Math.max(-1.5, Math.min(1.5, Number(CONFIG.LR_FRACTIONAL_DELAY_SAMPLES)));
     CONFIG.PHOENIX_BASE_URL = normalizePhoenixBaseUrlForCurrentClient(CONFIG.PHOENIX_BASE_URL || CONFIG_DEFAULTS.PHOENIX_BASE_URL || DEFAULT_PHOENIX_BASE_URL);
     CONFIG.PPM_DIN_FAST_ATTACK = !!CONFIG.PPM_DIN_FAST_ATTACK;
+    // Migrate stale profiles: detector ballistics are standards profiles,
+    // not user-adjustable display preferences.
+    CONFIG.PPM_DIN_ATTACK_MS = 10;
+    CONFIG.PPM_DIN_DECAY_DB_PER_S = 20 / 1.5;
+    CONFIG.PPM_DIN_HOLD_DECAY_DB_PER_S = 20 / 1.5;
+    CONFIG.PPM_EBU_ATTACK_MS = 10;
+    CONFIG.PPM_EBU_DECAY_DB_PER_S = 24 / 2.8;
+    CONFIG.PPM_EBU_HOLD_DECAY_DB_PER_S = 24 / 2.8;
     CONFIG.HIFI_PEAK_ALIGNMENT = (CONFIG.HIFI_PEAK_ALIGNMENT === 'ppm_din_zero' || CONFIG.HIFI_PEAK_ALIGNMENT === 'dbfs_zero')
       ? 'ppm_din_zero'
       : 'ppm_din_minus5';
@@ -969,6 +989,10 @@ function buildPhoenixGlobalConfigPayload() {
     if (raw === 'stopwatch') return 'stopwatch';
     return fallback;
   };
+  const normalizeSpectroScroll = (value) => {
+    const number = Number(value);
+    return [0.5, 1, 2, 4, 6].includes(number) ? number : 1;
+  };
   const normalizePeakHistoryScroll = (value) => {
     const allowed = new Set([0.5, 1, 2, 4, 6]);
     const num = Number(value);
@@ -990,11 +1014,11 @@ function buildPhoenixGlobalConfigPayload() {
     monoInput: !!CONFIG.MONO_INPUT,
     lrFractionalDelayEnabled: !!CONFIG.LR_FRACTIONAL_DELAY_ENABLED,
     lrFractionalDelaySamples: Number.isFinite(CONFIG.LR_FRACTIONAL_DELAY_SAMPLES) ? CONFIG.LR_FRACTIONAL_DELAY_SAMPLES : (CONFIG_DEFAULTS.LR_FRACTIONAL_DELAY_SAMPLES ?? 0.996),
-    ppmDinAttackMs: Number.isFinite(CONFIG.PPM_DIN_ATTACK_MS) ? CONFIG.PPM_DIN_ATTACK_MS : (CONFIG_DEFAULTS.PPM_DIN_ATTACK_MS ?? 5),
+    ppmDinAttackMs: 10,
-    ppmDinDecayDbPerS: Number.isFinite(CONFIG.PPM_DIN_DECAY_DB_PER_S) ? CONFIG.PPM_DIN_DECAY_DB_PER_S : (CONFIG_DEFAULTS.PPM_DIN_DECAY_DB_PER_S ?? 11.8),
+    ppmDinDecayDbPerS: 20 / 1.5,
     ppmDinFastAttack: !!CONFIG.PPM_DIN_FAST_ATTACK,
-    ppmEbuAttackMs: Number.isFinite(CONFIG.PPM_EBU_ATTACK_MS) ? CONFIG.PPM_EBU_ATTACK_MS : (CONFIG_DEFAULTS.PPM_EBU_ATTACK_MS ?? 10),
+    ppmEbuAttackMs: 10,
-    ppmEbuDecayDbPerS: Number.isFinite(CONFIG.PPM_EBU_DECAY_DB_PER_S) ? CONFIG.PPM_EBU_DECAY_DB_PER_S : (CONFIG_DEFAULTS.PPM_EBU_DECAY_DB_PER_S ?? 8.6),
+    ppmEbuDecayDbPerS: 24 / 2.8,
     lufsIWindowMin: Number.isFinite(CONFIG.LUFS_I_WINDOW_MIN) ? CONFIG.LUFS_I_WINDOW_MIN : (CONFIG_DEFAULTS.LUFS_I_WINDOW_MIN ?? 4),
     lufsINormEnabled: !!CONFIG.LUFS_I_NORM_ENABLED,
     ppmDinLoudnessBoxes: !!CONFIG.PPM_DIN_LOUDNESS_BOXES,
@@ -1016,6 +1040,8 @@ function buildPhoenixGlobalConfigPayload() {
     clockLedColor: normalizeColor(CONFIG.CLOCK_LED_COLOR, CONFIG_DEFAULTS.CLOCK_LED_COLOR || '#ff0000'),
     headerTextColor: normalizeColor(CONFIG.HEADER_TEXT_COLOR, CONFIG_DEFAULTS.HEADER_TEXT_COLOR || '#ffe066'),
     rtaBarBaseColor: normalizeColor(CONFIG.RTA_BAR_BASE_COLOR, CONFIG_DEFAULTS.RTA_BAR_BASE_COLOR || '#ffe066'),
+    spectroGamma: Number.isFinite(CONFIG.SPECTRO_GAMMA) ? Math.max(0.3, Math.min(1.2, CONFIG.SPECTRO_GAMMA)) : 0.9,
+    spectroScrollMode: normalizeSpectroScroll(CONFIG.SPECTRO_SCROLL_MODE),
     peakHistoryScrollMode: normalizePeakHistoryScroll(CONFIG.PEAK_HISTORY_SCROLL_MODE),
     peakHistoryFillEnabled: !!CONFIG.PEAK_HISTORY_FILL_ENABLED,
     peakHistoryFillInvert: !!CONFIG.PEAK_HISTORY_FILL_INVERT,
@@ -1063,6 +1089,10 @@ function applyPhoenixGlobalConfig(payload = {}) {
     if (raw === 'stopwatch') return 'stopwatch';
     return fallback;
   };
+  const normalizeSpectroScroll = (value) => {
+    const number = Number(value);
+    return [0.5, 1, 2, 4, 6].includes(number) ? number : 1;
+  };
   const fft = Number(payload.fftSize);
   if (Number.isFinite(fft)) {
     CONFIG.FFT_SIZE = (fft === 2048 || fft === 4096 || fft === 8192 || fft === 16384)
@@ -1073,15 +1103,20 @@ function applyPhoenixGlobalConfig(payload = {}) {
     const mode = String(payload.rtaBpoMode || '').trim();
     CONFIG.RTA_BPO_MODE = (mode === '1_3' || mode === '1_6' || mode === '1_12') ? mode : '1_6';
   }
-  const dinAttack = Number(payload.ppmDinAttackMs);
+  if (CONFIG.RTA_BAR_LAYOUT === 'rtw') {
-  if (Number.isFinite(dinAttack)) CONFIG.PPM_DIN_ATTACK_MS = Math.max(0.1, Math.min(100, dinAttack));
+    CONFIG.RTA_ENGINE = 'iir';
-  const dinDecay = Number(payload.ppmDinDecayDbPerS);
+    CONFIG.RTA_BPO_MODE = '1_3';
-  if (Number.isFinite(dinDecay)) CONFIG.PPM_DIN_DECAY_DB_PER_S = Math.max(0.1, Math.min(120, dinDecay));
+    CONFIG.RTA_IIR_ORDER = 6;
+    CONFIG.RTA_FREQ_RANGE = 'norm';
+  }
+  const spectroGamma = Number(payload.spectroGamma);
+  if (Number.isFinite(spectroGamma)) CONFIG.SPECTRO_GAMMA = Math.max(0.3, Math.min(1.2, spectroGamma));
+  if ('spectroScrollMode' in payload) CONFIG.SPECTRO_SCROLL_MODE = normalizeSpectroScroll(payload.spectroScrollMode);
+  CONFIG.PPM_DIN_ATTACK_MS = 10;
+  CONFIG.PPM_DIN_DECAY_DB_PER_S = 20 / 1.5;
   if ('ppmDinFastAttack' in payload) CONFIG.PPM_DIN_FAST_ATTACK = !!payload.ppmDinFastAttack;
-  const ebuAttack = Number(payload.ppmEbuAttackMs);
+  CONFIG.PPM_EBU_ATTACK_MS = 10;
-  if (Number.isFinite(ebuAttack)) CONFIG.PPM_EBU_ATTACK_MS = Math.max(0.1, Math.min(100, ebuAttack));
+  CONFIG.PPM_EBU_DECAY_DB_PER_S = 24 / 2.8;
-  const ebuDecay = Number(payload.ppmEbuDecayDbPerS);
-  if (Number.isFinite(ebuDecay)) CONFIG.PPM_EBU_DECAY_DB_PER_S = Math.max(0.1, Math.min(120, ebuDecay));
   const lufsWin = Number(payload.lufsIWindowMin);
   if (Number.isFinite(lufsWin)) CONFIG.LUFS_I_WINDOW_MIN = Math.max(1, Math.min(10, Math.round(lufsWin)));
   if ('lufsINormEnabled' in payload) CONFIG.LUFS_I_NORM_ENABLED = !!payload.lufsINormEnabled;

www/index.html

@@ -307,7 +307,7 @@
             <label>Bänder pro Oktave</label>
             <select id="opt_rtaBpo" style="width:150px">
               <option value="1_3">1/3 Oktave</option>
-              <option value="1_6" selected>1/6 Oktave</option>
+              <option value="1_6">1/6 Oktave</option>
               <option value="1_12">1/12 Oktave</option>
             </select>
             <small>Filterauflösung – Anzahl Bänder</small>
@@ -355,7 +355,9 @@
             <select id="opt_rtaIntegration" style="width:150px">
               <option value="impulse">Impulse</option>
               <option value="fast" selected>Fast</option>
+              <option value="medium">Medium</option>
               <option value="slow">Slow</option>
+              <option value="average">Average</option>
               <option value="peak">Peak (10 ms)</option>
             </select>
             <small>Reaktionsmodus</small>
@@ -1024,7 +1026,7 @@
 	                  <input id="opt_ppmDinFastAttack" type="checkbox">
 	                  PPM DIN: Fast‑Attack (sofort, nicht normgerecht)
 	                </label>
-	                <small>Umgeht die 5‑ms‑Integration und lässt die Anzeige sofort ansteigen (kann gefühltes Anzeige‑Lag durch Latenz reduzieren).</small>
+	                <small>Umgeht die feste 10-ms-Normintegration und zeigt Sample-Peaks sofort an (kann gefühltes Anzeige-Lag reduzieren).</small>
 	              </div>
 	              <div class="opt">
 	                <label class="row" style="align-items:center;gap:8px">
@@ -1841,7 +1843,7 @@
 	    <div id="ppmDinFastWarn" class="rec-warning" style="display:none">
 	      <div class="rec-warning-box">
 	        <h3>PPM DIN – Fast‑Attack</h3>
-	        <p>Dieser Modus lässt das PPM DIN sofort ansteigen (ohne 5‑ms‑Integration).</p>
+	        <p>Dieser Sample-Peak-Sondermodus lässt das PPM DIN sofort ansteigen (ohne 10-ms-Normintegration).</p>
 	        <p>Dadurch kann die Anzeige „schneller“ wirken, ist aber <b>nicht mehr normgerecht</b> (DIN 45406 / IEC 60268‑10).</p>
 	        <p>Hinweis: Das ändert nur die Anzeige‑Ballistik und kompensiert keine echte Audio‑Latenz.</p>
 	        <button id="ppmDinFastWarnBtn" class="btn btn-lg" type="button">Verstanden</button>

www/meters/ppm_din.js

@@ -8,7 +8,7 @@ import { HEADER_BG, LABEL_COLOR, MID_COLOR, WARN_COLOR } from '../core/theme.js'
 
 export const id = 'ppm-din';
 
-const DEFAULT_DECAY_DB_PER_S = 20 / 1.7; // 20 dB in ca. 1.7 s → ~11.76 dB/s
+const DEFAULT_DECAY_DB_PER_S = 20 / 1.5; // RTW/DIN: 20 dB in 1.5 s
 const DEFAULT_HOLD_MS = 1000;
 
 const DIN_SCALE = [
@@ -79,7 +79,7 @@ export function initShared(CONFIG = {}) {
     },
     // Offset for DIN uses PPM_DIN_OFFSET so that 0 dB on the meter aligns
     // properly with the Permitted Maximum Level (PML).  According to the
-    // DIN Type I specification, 0 dBu (≈−15 dBFS peak) should read −9 dB.
+    // selected alignment profile maps 0 dBu to either -6 dB or legacy -9 dB.
     offset: Number(CONFIG.PPM_DIN_OFFSET) || 0,
     refDbfsFor0: Number.isFinite(CONFIG.PPM_REF_DBFS_PEAK_FOR_0_DBU)
       ? CONFIG.PPM_REF_DBFS_PEAK_FOR_0_DBU

www/meters/ppm_ebu.js

@@ -4,7 +4,7 @@ import { drawCachedStaticLayer } from './static_layer.js';
 import { HEADER_BG, LABEL_COLOR, MID_COLOR, WARN_COLOR } from '../core/theme.js';
 
 // meters/ppm_ebu.js — PPM (EBU) mit linearer Skala
-// - Messbereich: -14 … +14 dB (Clamping/Anzeigegrenzen)
+// - Messbereich: -12 … +12 dB
 // - Rote Zone ab +9 dB
 // - Ticks: große Marken bei -12/-8/-4/0/+4/+8/+12, kleine u. a. bei -10/-6/…/+10
 // - Labels: nur für die großen Ticks; bei 0 statt "0" → "TEST"
@@ -12,7 +12,7 @@ import { HEADER_BG, LABEL_COLOR, MID_COLOR, WARN_COLOR } from '../core/theme.js'
 export const id = 'ppm-ebu';
 
 const DEFAULT_ATTACK_MS = 10;       // Type IIb typisch ~10 ms
-const DEFAULT_DECAY_DB_PER_S = 8.6; // ~24 dB in 2.8 s
+const DEFAULT_DECAY_DB_PER_S = 24 / 2.8;
 const DEFAULT_HOLD_MS = 750;
 
 const EBU_MAJOR_TICKS = [-12, -8, -4, 0, +4, +8, +12];
@@ -21,10 +21,10 @@ const EBU_MINOR_TICKS = [-10, -6, -2, +2, +6, +9, +10];
 export function initShared(CONFIG = {}) {
   const now = performance.now();
   // Use EBU-specific configuration values.  PPM_EBU_BOTTOM defines the
-  // bottom of the EBU scale (default -14 dB) and PPM_EBU_HOLD_MS defines
+  // bottom of the EBU scale (default -12 dB) and PPM_EBU_HOLD_MS defines
   // the peak-hold duration.  This ensures the EBU meter aligns with
   // the Type IIb specification (0 dB at AL, +9 dB red start).
-  const bottom = Number.isFinite(CONFIG.PPM_EBU_BOTTOM) ? CONFIG.PPM_EBU_BOTTOM : -14;
+  const bottom = Number.isFinite(CONFIG.PPM_EBU_BOTTOM) ? CONFIG.PPM_EBU_BOTTOM : -12;
   const holdMs = Number.isFinite(CONFIG.PPM_EBU_HOLD_MS) ? CONFIG.PPM_EBU_HOLD_MS : DEFAULT_HOLD_MS;
   const decayCfg = Number.isFinite(CONFIG.PPM_EBU_DECAY_DB_PER_S)
     ? CONFIG.PPM_EBU_DECAY_DB_PER_S
@@ -40,7 +40,7 @@ export function initShared(CONFIG = {}) {
     },
     _ballistics: {
       // The EBU (Type IIb) PPM uses a ~10 ms attack and a decay of 24 dB
-      // in 2.8 s (≈8.6 dB/s).
+      // in 2.8 s (≈8.57 dB/s).
       attackMs: Number.isFinite(CONFIG.PPM_EBU_ATTACK_MS) ? CONFIG.PPM_EBU_ATTACK_MS : DEFAULT_ATTACK_MS,
       decayDbPerS: decayCfg,
     },
@@ -83,8 +83,8 @@ export function draw(g, rect, CONFIG = {}, shared) {
   const __effOff  = Number(CONFIG.PPM_EBU_OFFSET) || 0;
   const __offCorr = __effOff - (shared.offset || 0);
 
-  const PPM_TOP    = Number.isFinite(CONFIG.PPM_EBU_TOP)    ? CONFIG.PPM_EBU_TOP    : +14;
+  const PPM_TOP    = Number.isFinite(CONFIG.PPM_EBU_TOP)    ? CONFIG.PPM_EBU_TOP    : +12;
-  const PPM_BOTTOM = Number.isFinite(CONFIG.PPM_EBU_BOTTOM) ? CONFIG.PPM_EBU_BOTTOM : -14;
+  const PPM_BOTTOM = Number.isFinite(CONFIG.PPM_EBU_BOTTOM) ? CONFIG.PPM_EBU_BOTTOM : -12;
   const RED_START  = Number.isFinite(CONFIG.PPM_EBU_RED_START) ? CONFIG.PPM_EBU_RED_START : +9;
 
   const redOnly    = CONFIG.PPM_RED_BAR_ONLY !== false;
@@ -271,7 +271,7 @@ function drawPpmEbuStaticOverlay(g, shared, rect, CONFIG, geom, mapY, PPM_TOP, P
     topPad,
     CONFIG.METER_BAR_THIN || 0.55,
     CONFIG.PPM_EBU_TOP ?? 14,
-    CONFIG.PPM_EBU_BOTTOM ?? -14,
+    CONFIG.PPM_EBU_BOTTOM ?? -12,
     CONFIG.PPM_EBU_RED_START ?? 9,
     CONFIG.AL_MARKERS_ENABLED === false ? 0 : 1,
     METER_HEADER_FONT,

www/ui/options.js

@@ -290,7 +290,7 @@ function syncUI() {
     ['opt_rtaIntegration', CONFIG.RTA_INTEGRATION || 'fast'],
     ['opt_rtaBallistics', CONFIG.RTA_BALLISTICS_MODE || 'average'],
     ['opt_rtaHoldMode', CONFIG.RTA_PEAK_HOLD_MODE || 'auto'],
-    ['opt_rtaHoldTime', CONFIG.RTA_PEAK_HOLD_SEC ?? 2],
+    ['opt_rtaHoldTime', CONFIG.RTA_PEAK_HOLD_SEC ?? 2.5],
     ['opt_rtaDecay', CONFIG.RTA_PEAK_DECAY_DB_PER_S ?? 20],
     ['opt_rtaDisplayHold', CONFIG.RTA_DISPLAY_HOLD_SEC ?? 0],
     ['opt_spectroGamma', CONFIG.SPECTRO_GAMMA ?? 0.9, 'val_spectroGamma', (v)=>Number(v).toFixed(2)],
@@ -1054,13 +1054,23 @@ function wireHandlers(env) {
   }, null, null, true);
 
   // Hold-/Decay-Parameter
-  h('opt_rtaEngine', v => { CONFIG.RTA_ENGINE = (v === 'iir') ? 'iir' : 'fft'; });
+  h('opt_rtaEngine', v => {
+    CONFIG.RTA_ENGINE = CONFIG.RTA_BAR_LAYOUT === 'rtw' ? 'iir' : ((v === 'iir') ? 'iir' : 'fft');
+    return CONFIG.RTA_ENGINE;
+  });
   h('opt_rtaBpo', v => {
     const allowed = new Set(['1_3', '1_6', '1_12']);
-    CONFIG.RTA_BPO_MODE = allowed.has(v) ? v : '1_6';
+    CONFIG.RTA_BPO_MODE = CONFIG.RTA_BAR_LAYOUT === 'rtw'
+      ? '1_3'
+      : (allowed.has(v) ? v : '1_6');
     notifyPhoenixGlobalConfig();
+    return CONFIG.RTA_BPO_MODE;
   });
   h('opt_rtaOrder', v => {
+    if (CONFIG.RTA_BAR_LAYOUT === 'rtw') {
+      CONFIG.RTA_IIR_ORDER = 6;
+      return 6;
+    }
     let val = Math.round(+v);
     if (!Number.isFinite(val)) val = 4;
     val = Math.max(2, Math.min(8, val));
@@ -1068,12 +1078,33 @@ function wireHandlers(env) {
     CONFIG.RTA_IIR_ORDER = val;
     return val;
   });
-  h('opt_rtaFreq', v => { CONFIG.RTA_FREQ_RANGE = (v === 'lf') ? 'lf' : 'norm'; });
+  h('opt_rtaFreq', v => {
+    CONFIG.RTA_FREQ_RANGE = CONFIG.RTA_BAR_LAYOUT === 'rtw' ? 'norm' : ((v === 'lf') ? 'lf' : 'norm');
+    return CONFIG.RTA_FREQ_RANGE;
+  });
   h('opt_rtaDisplayGainFft', v => { CONFIG.RTA_DISPLAY_GAIN_FFT_DB = clamp(+v, -25, 25); }, 'val_rtaDisplayGainFft', v=>`${v} dB`);
   h('opt_rtaDisplayGainIir', v => { CONFIG.RTA_DISPLAY_GAIN_IIR_DB = clamp(+v, -25, 25); }, 'val_rtaDisplayGainIir', v=>`${v} dB`);
   h('opt_rtaLayout', v => {
     const val = (v === 'rtw') ? 'rtw' : 'iec';
     CONFIG.RTA_BAR_LAYOUT = val;
+    if (val === 'rtw') {
+      CONFIG.RTA_ENGINE = 'iir';
+      CONFIG.RTA_BPO_MODE = '1_3';
+      CONFIG.RTA_IIR_ORDER = 6;
+      CONFIG.RTA_FREQ_RANGE = 'norm';
+      const forced = {
+        opt_rtaEngine: 'iir',
+        opt_rtaBpo: '1_3',
+        opt_rtaOrder: '6',
+        opt_rtaFreq: 'norm',
+      };
+      for (const [id, value] of Object.entries(forced)) {
+        const control = document.getElementById(id);
+        if (control) control.value = value;
+      }
+      notifyPhoenixGlobalConfig();
+    }
+    return val;
   });
   h('opt_rtaBarBaseColor', v => {
     CONFIG.RTA_BAR_BASE_COLOR = v || '#ffe066';
@@ -1085,8 +1116,9 @@ function wireHandlers(env) {
     CONFIG.RTA_WEIGHTING = allowed.has(v) ? v : 'z';
   });
   h('opt_rtaIntegration', v => {
-    const allowed = new Set(['impulse','fast','slow','peak']);
+    const allowed = new Set(['impulse','fast','medium','slow','average','peak']);
     CONFIG.RTA_INTEGRATION = allowed.has(v) ? v : 'fast';
+    return CONFIG.RTA_INTEGRATION;
   });
   h('opt_rtaBallistics', v => {
     const val = (v === 'peak' || v === 'both' || v === 'average') ? v : 'average';
@@ -1097,12 +1129,19 @@ function wireHandlers(env) {
     const allowed = new Set(['off','auto','manual']);
     CONFIG.RTA_PEAK_HOLD_MODE = allowed.has(v) ? v : 'auto';
   });
-  h('opt_rtaHoldTime', v => { CONFIG.RTA_PEAK_HOLD_SEC = clamp(+v, 0, 30); });
+  h('opt_rtaHoldTime', v => {
+    const requested = clamp(+v, 0, 30);
+    CONFIG.RTA_PEAK_HOLD_SEC = CONFIG.RTA_BAR_LAYOUT === 'rtw'
+      ? (requested < 3.25 ? 2.5 : 4.0)
+      : requested;
+    return CONFIG.RTA_PEAK_HOLD_SEC;
+  });
   h('opt_rtaDecay', v => { CONFIG.RTA_PEAK_DECAY_DB_PER_S = clamp(+v, 1, 60); });
   h('opt_rtaDisplayHold', v => { CONFIG.RTA_DISPLAY_HOLD_SEC = clamp(+v, 0, 5); });
   h('opt_spectroGamma', v => {
     const num = clamp(parseFloat(v), 0.3, 1.2);
     CONFIG.SPECTRO_GAMMA = num;
+    notifyPhoenixGlobalConfig();
     return num;
   }, 'val_spectroGamma', (v)=>Number(v).toFixed(2));
   h('opt_spectroScroll', v => {
@@ -1110,6 +1149,7 @@ function wireHandlers(env) {
     const num = Number(v);
     const val = allowed.has(num) ? num : 1;
     CONFIG.SPECTRO_SCROLL_MODE = val;
+    notifyPhoenixGlobalConfig();
     return val;
   });
   h('opt_peakHistScroll', v => {

www/views/goniometer_rtw.js

@@ -16,8 +16,6 @@ const METER_SLOT_SHRINK = 24;
 const METER_PAD_TOP = 1;
 const METER_PAD_BOTTOM = -7;
 const METER_EXTRA_BOTTOM_PAD = 6;
-const CORR_ATTACK_S = 1.5;
-const CORR_RELEASE_S = 2.5;
 const GONIO_GAIN_MIN_DB = -35;
 const GONIO_GAIN_MAX_DB = 35;
 const BASE_TARGET = 1.0;
@@ -26,8 +24,7 @@ const BASE_ZOOM = 1.0;
 const BASE_GONIO_SCALE = (BASE_TARGET / ALIGN_PEAK) * Math.pow(10, -BASE_HEADROOM_DB / 20) * BASE_ZOOM;
 const AGC_TARGET_DB = linearToDb(ALIGN_PEAK);
 const CORR_SILENCE_THRESHOLD_DEFAULT = -75;
-const CORR_SILENCE_HOLD_MS = 30000;
+const MAX_TRAIL_FRAMES = 48;
-const CORR_SILENCE_DRIFT_MS = 60000;
 
 function computePanelSlotWidth(canvasWidth, slotCount = METER_SLOTS, slotGap = 12) {
   const n = Math.max(1, Math.min(METER_SLOTS, slotCount | 0));
@@ -39,11 +36,6 @@ function computePanelSlotWidth(canvasWidth, slotCount = METER_SLOTS, slotGap = 1
 
 export function init() {
   return {
-    corrDisplayed: 0,
-    corrMeter: 0,
-    corrLastTs: 0,
-    corrLastValid: 0,
-    corrSilenceSince: 0,
     gateLevel: 1,
     gateLastTs: 0,
     agcEnv: 1e-3,
@@ -51,6 +43,7 @@ export function init() {
     agcLastTs: 0,
     traceBuffer: new Float32Array(0),
     lineTrails: [],
+    trailPool: [],
     staticLayerCanvas: null,
     staticLayerCtx: null,
     staticLayerKey: '',
@@ -66,13 +59,7 @@ export async function render(env, state) {
 
   const wakeTs = Number.isFinite(env?.screensaverWakeTs) ? Number(env.screensaverWakeTs) : 0;
   if (wakeTs && state?._lastWakeTs !== wakeTs) {
-    // Nach Screensaver-Wake: Korrelation sauber zurücksetzen, damit kein "alter" Wert (z.B. +1) stehen bleibt.
     state._lastWakeTs = wakeTs;
-    state.corrDisplayed = 0;
-    state.corrMeter = 0;
-    state.corrLastTs = 0;
-    state.corrLastValid = 0;
-    state.corrSilenceSince = frameNow;
   }
 
   const slotsRaw = env.slots?.(id) || ['vu', 'ppm-ebu', 'tp'];
@@ -101,62 +88,20 @@ export async function render(env, state) {
     : null;
   renderTrace(g, state, trace, layout.scope, style, xyReady && gate.active, settings);
 
-  const silenceGateEnabled = CONFIG?.XY_SILENCE_GATE_ENABLED !== false;
+  // Correlation is measured continuously in the audio DSP. Do not add a
-  const corrThreshold = resolveCorrThreshold(CONFIG);
+  // second, frame-rate-dependent browser integration here.
-  const rmsL = Number.isFinite(env.audio?.rmsDb?.L) ? env.audio.rmsDb.L : -120;
+  const corrVisual = Number.isFinite(audio?.correlation) ? clamp1(audio.correlation) : 0;
-  const rmsR = Number.isFinite(env.audio?.rmsDb?.R) ? env.audio.rmsDb.R : -120;
+  const corrNegativePeak = Number.isFinite(audio?.correlationNegativePeak)
-  const activeL = audioFresh && (!silenceGateEnabled || (rmsL >= corrThreshold));
+    ? clamp1(audio.correlationNegativePeak)
-  const activeR = audioFresh && (!silenceGateEnabled || (rmsR >= corrThreshold));
+    : 0;
-
-  let corrTarget = 0;
-  const canCorr = xyReady && utils?.correlation;
-  const zeroOnSilence = !!CONFIG?.CORR_ZERO_ON_SILENCE;
-  const bothSilent = !activeL && !activeR;
-
-  if (activeL && activeR && canCorr) {
-    // Beide Kanäle aktiv → echte Korrelation aus L/R-Samples
-    const corrRaw = utils.correlation(
-      xyData.xyL,
-      xyData.xyR,
-      Number.isFinite(state.corrDisplayed) ? state.corrDisplayed : 0,
-      CONFIG.CORR_SMOOTH,
-    );
-    if (Number.isFinite(corrRaw)) {
-      state.corrDisplayed = corrRaw;
-      state.corrLastValid = corrRaw;
-      state.corrSilenceSince = 0;
-      corrTarget = corrRaw;
-    }
-  } else if (activeL !== activeR) {
-    // Nur ein Kanal aktiv → hart auf 0, keine Hold-/Decay-Logik
-    state.corrSilenceSince = 0;
-    corrTarget = 0;
-  } else {
-    if (zeroOnSilence && bothSilent) {
-      // Beide still → zügig Richtung 0 (ohne Hold/Drift)
-      state.corrLastValid = 0;
-      state.corrSilenceSince = frameNow;
-      corrTarget = 0;
-    } else {
-      // Beide still → Hold + Drift zur Mitte
-      if (!state.corrSilenceSince) state.corrSilenceSince = frameNow;
-      corrTarget = resolveCorrTarget(state, frameNow);
-    }
-  }
-
-  const fastZero = zeroOnSilence && bothSilent;
-  const corrVisual = updateCorrelationDisplay(state, corrTarget, frameNow, fastZero ? true : gate.active);
-  if (fastZero) {
-    // Damit die nächste echte Korrelation nicht noch an einem alten Glättungswert "hängt".
-    state.corrDisplayed = corrVisual;
-  }
   drawCorrelationBar(
     g,
     layout.plot.x + layout.plot.w / 2,
     layout.plot.y + layout.plot.h - 28,
     Math.round(Math.min(layout.scope.w * 0.75, layout.plot.w - 50)),
     18,
-    corrVisual
+    corrVisual,
+    corrNegativePeak,
   );
 
   if (slots.length) {
@@ -755,52 +700,6 @@ function getNow() {
   return Date.now();
 }
 
-function updateCorrelationDisplay(state, target, nowTs, gateActive = true) {
-  const prev = Number.isFinite(state.corrMeter) ? state.corrMeter : target;
-  const lastTs = Number.isFinite(state.corrLastTs) ? state.corrLastTs : nowTs;
-  const dt = Math.max(0, (nowTs - lastTs) / 1000);
-  if (!dt) {
-    state.corrMeter = clamp1(target);
-    state.corrLastTs = nowTs;
-    return state.corrMeter;
-  }
-  const rising = Math.abs(target) > Math.abs(prev);
-  // Schneller einrasten, wenn Gate aktiv ist; etwas zäher auf Null auslaufen, wenn Stille.
-  const tauAttack = gateActive ? 0.08 : CORR_ATTACK_S;
-  const tauRelease = gateActive ? 0.35 : CORR_RELEASE_S;
-  const tau = rising ? tauAttack : tauRelease;
-  const alpha = 1 - Math.exp(-dt / Math.max(0.001, tau));
-  const next = clamp1(prev + (target - prev) * alpha);
-  state.corrMeter = next;
-  state.corrLastTs = nowTs;
-  return next;
-}
-
-function resolveCorrThreshold(CONFIG = {}) {
-  if (Number.isFinite(CONFIG.XY_SILENCE_THRESHOLD_RMS_DBFS)) {
-    return CONFIG.XY_SILENCE_THRESHOLD_RMS_DBFS;
-  }
-  if (Number.isFinite(CONFIG.CORR_SILENCE_THRESHOLD_RMS_DBFS)) {
-    return CONFIG.CORR_SILENCE_THRESHOLD_RMS_DBFS;
-  }
-  return CORR_SILENCE_THRESHOLD_DEFAULT;
-}
-
-function resolveCorrTarget(state, nowTs) {
-  const lastValid = Number.isFinite(state.corrLastValid) ? state.corrLastValid : 0;
-  if (!state.corrSilenceSince) {
-    return lastValid;
-  }
-  const holdMs = CORR_SILENCE_HOLD_MS;
-  const driftMs = CORR_SILENCE_DRIFT_MS;
-  const elapsed = Math.max(0, nowTs - state.corrSilenceSince);
-  if (elapsed <= holdMs) {
-    return lastValid;
-  }
-  const t = Math.min(1, (elapsed - holdMs) / Math.max(1, driftMs));
-  return lastValid * (1 - t);
-}
-
 function computeAgcGain(state, xyData, nowTs) {
   const attackTau = 0.001; // 1 ms
   const releaseDbPerS = 10;
@@ -857,7 +756,7 @@ function dbToLinear(db) {
 // -----------------------------------------------------------------------------
 // Correlation bar helper
 
-function drawCorrelationBar(g, centerX, y, w, h, val) {
+function drawCorrelationBar(g, centerX, y, w, h, val, negativePeak) {
   const x = Math.floor(centerX - w / 2);
   g.save();
   g.strokeStyle = FRAME_COLOR; g.lineWidth = 2; g.strokeRect(x, y, w, h);
@@ -886,6 +785,16 @@ function drawCorrelationBar(g, centerX, y, w, h, val) {
   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) {
+    const markerX = clampCenter(mid + (clamp1(negativePeak) * 0.5) * w);
+    g.fillStyle = WARN_COLOR;
+    g.beginPath();
+    g.moveTo(markerX, y - 1);
+    g.lineTo(markerX - 5, y - 7);
+    g.lineTo(markerX + 5, y - 7);
+    g.closePath();
+    g.fill();
+  }
   g.restore();
 }
 

www/views/realtime.js

@@ -71,14 +71,15 @@ export async function render(env, state) {
   const nyq = audio.nyq || 24000;
   const analyser = audio.getAnalyser?.();
   const buf = audio.getFreqBuffer?.();
-  const useIirEngine = (CONFIG.RTA_ENGINE || 'fft') === 'iir';
   const rtaData = typeof audio.getRtaData === 'function'
     ? audio.getRtaData()
     : null;
+  const useIirEngine = rtaData?.engine === 'iir'
+    || ((CONFIG.RTA_ENGINE || 'fft') === 'iir');
   const useNativeFftEngine = !useIirEngine && rtaData && rtaData.engine === 'fft';
   const nativeRtaPacket = (useIirEngine || useNativeFftEngine) ? rtaData : null;
   const displayRtaPacket = (nativeRtaPacket && CONFIG.RTA_BAR_LAYOUT === 'rtw')
-    ? selectLocalRtwPacket(nativeRtaPacket, CONFIG.RTA_BPO_MODE || '1_6')
+    ? selectLocalRtwPacket(nativeRtaPacket, nativeRtaPacket.bpo || '1_3')
     : nativeRtaPacket;
 
   const topInset = Number.isFinite(env?.topInset) ? Number(env.topInset) : DEFAULT_TOP_INSET;
@@ -177,9 +178,9 @@ export async function render(env, state) {
       } else {
         const integrated = baseLevels;
         const displayBase = applyDisplayHold(state, integrated, CONFIG, range);
-        const display = (CONFIG.REALTIME_RENDER_STYLE || 'bars') === 'bars'
+        // Native IIR values already contain the selected power-domain
-          ? applyRealtimeBarBallistics(state, displayBase, CONFIG, range)
+        // integration. A second browser attack/hold stage would falsify it.
-          : displayBase;
+        const display = displayBase;
         applyPeakHold(state, integrated, CONFIG, range);
         state.displayLevels = display;
         state.currentRange = range;
@@ -320,10 +321,11 @@ function resetState(state) {
 
 function ensureBands(state, utils, CONFIG, nyq, binCount, freqBounds, range, rtaPacket) {
   const freqRange = CONFIG.RTA_FREQ_RANGE === 'lf' ? 'lf' : 'norm';
-  const bpo = CONFIG.RTA_BPO_MODE || '1_6';
-  const engine = CONFIG.RTA_ENGINE || 'fft';
   const layoutMode = CONFIG.RTA_BAR_LAYOUT === 'rtw' ? 'rtw' : 'iec';
-  const rtaCenters = (layoutMode === 'rtw') ? getRtwCenters(bpo) : null;
+  const bpo = layoutMode === 'rtw' ? (rtaPacket?.bpo || '1_3') : (CONFIG.RTA_BPO_MODE || '1_6');
+  const engine = rtaPacket?.engine || CONFIG.RTA_ENGINE || 'fft';
+  const packetCenters = isVectorLike(rtaPacket?.centers) ? Array.from(rtaPacket.centers) : null;
+  const rtaCenters = (layoutMode === 'rtw') ? (packetCenters || getRtwCenters(bpo)) : null;
   const centerKey = rtaCenters
     ? `${rtaCenters.length}:${rtaCenters[0]}:${rtaCenters[rtaCenters.length - 1]}`
     : 'static';

www/views/spectrogram.js

@@ -15,6 +15,9 @@ const SMOOTHING_MAX = 0.2;
 const TIME_GRID_SPACING = 100;
 const SPECTROGRAM_ID = 'spectrogram';
 const SPECTRO_RENDER_SCALE = 0.85;
+const BASE_SCROLL_CSS_PX_PER_SECOND = 60;
+const WORKER_WATCHDOG_MS = 750;
+const MAX_SCROLL_COLUMNS_PER_DRAW = 64;
 const SUPPORTS_WORKER = typeof window !== 'undefined'
   && typeof Worker !== 'undefined'
   && typeof HTMLCanvasElement !== 'undefined'
@@ -38,6 +41,13 @@ export function init() {
     useWorker: false, // wird im Render je nach Config gesetzt
     worker: null,
     workerReady: false,
+    workerBusy: false,
+    workerMessageId: 0,
+    workerWatchdog: null,
+    pendingWorkerColumn: null,
+    pendingWorkerRepeat: 0,
+    pendingWorkerDropped: 0,
+    workerStats: { sent: 0, drawn: 0, dropped: 0, restarts: 0, lastDrawMs: 0 },
     offscreenWidth: 0,
     offscreenHeight: 0,
     spectroCanvasEl: null,
@@ -93,6 +103,10 @@ export async function render(env, state) {
   }
   // Config-Flag schaltet Worker ein (default true), wenn Offscreen verfügbar
   state.useWorker = SUPPORTS_WORKER && !!env.config?.SPECTRO_USE_WORKER;
+  if (!state.useWorker && state.worker) {
+    teardownWorker(state);
+    removeSpectroCanvasElement(state);
+  }
   state._dbgNextLog = state._dbgNextLog || 0;
   
   const { ctx: g, rect, config: CONFIG, audio, meters } = env;
@@ -165,6 +179,7 @@ export async function render(env, state) {
   }
 
   const scrollRate = resolveScrollRate(CONFIG);
+  const outputPixelScale = state.useWorker ? (plotWpx / Math.max(1, plotW)) : 1;
   let spectroDirty = true;
   if (hasPhoenixSpectro) {
     spectroDirty = phoenixSpectroSeq !== (state.lastPhoenixSpectroSeq || 0);
@@ -173,15 +188,19 @@ export async function render(env, state) {
   let columnsToEmit = 0;
   if (hasPhoenixSpectro) {
     if (spectroDirty) {
-      state.scrollAccumulator = (state.scrollAccumulator || 0) + scrollRate;
+      const previousSeq = Number(state.lastPhoenixSpectroSeq || 0);
-      while (state.scrollAccumulator >= 1) {
+      const sequenceDelta = previousSeq > 0
-        columnsToEmit += 1;
+        ? Math.max(1, phoenixSpectroSeq - previousSeq)
-        state.scrollAccumulator -= 1;
+        : 1;
-      }
+      const fftSize = Number(env.audio?.phoenixSpectroMeta?.fftSize) || freqBuf.length * 2;
-      if (columnsToEmit < 1) {
+      const pixelsPerSourceFrame = spectrogramPixelsPerSourceFrame(scrollRate, fs, fftSize);
-        columnsToEmit = 1;
+      const scrollStep = stepScrollAccumulator(
-        state.scrollAccumulator = 0;
+        state.scrollAccumulator,
-      }
+        pixelsPerSourceFrame * outputPixelScale,
+        sequenceDelta,
+      );
+      state.scrollAccumulator = scrollStep.accumulator;
+      columnsToEmit = scrollStep.columns;
     }
   } else {
     const nowTs = performance.now();
@@ -206,15 +225,11 @@ export async function render(env, state) {
 
   if (columnsToEmit > 0 && spectroDirty) {
     const column = buildColumnData(state, freqBuf, range.bottom);
-    const columns = [];
+    if (state.useWorker) {
-    for (let i = 0; i < columnsToEmit; i++) {
+      queueColumnForWorker(state, column, columnsToEmit);
-      columns.push(i === 0 ? column : new Float32Array(column));
-    }
-
-    if (state.useWorker && state.workerReady) {
-      columns.forEach(col => sendColumnToWorker(state, col));
     } else {
-      columns.forEach(col => writeColumnToHistory(state, col));
+      const repeat = Math.min(state.width, columnsToEmit);
+      for (let index = 0; index < repeat; index++) writeColumnToHistory(state, column);
     }
   }
 
@@ -249,7 +264,7 @@ function setupWorker(state, widthPx, heightPx, range, gamma, freqBounds) {
       worker.onmessage = (event) => handleWorkerMessage(state, event);
       worker.onerror = () => {
         state.useWorker = false;
-        teardownWorker(state);
+        restartWorker(state);
       };
       const offscreen = canvasEl.transferControlToOffscreen();
       state.spectroCanvasEl = canvasEl;
@@ -310,6 +325,7 @@ function setupWorker(state, widthPx, heightPx, range, gamma, freqBounds) {
 }
 
 function teardownWorker(state) {
+  clearWorkerWatchdog(state);
   if (state.worker) {
     try { 
       state.worker.postMessage({ type: 'dispose' }); 
@@ -320,39 +336,97 @@ function teardownWorker(state) {
   }
   state.worker = null;
   state.workerReady = false;
-  state.spectroCanvasEl = null;
+  state.workerBusy = false;
-  state.spectroCanvasTransferred = false;
+  state.pendingWorkerColumn = null;
+  state.pendingWorkerRepeat = 0;
+  state.pendingWorkerDropped = 0;
 }
 
 function handleWorkerMessage(state, event) {
   const data = event.data || {};
   if (data.type === 'ready') {
     state.workerReady = true;
+    state.workerBusy = false;
+    pumpWorkerColumn(state);
+  } else if (data.type === 'drawn') {
+    if (Number(data.id) !== Number(state.workerMessageId)) return;
+    clearWorkerWatchdog(state);
+    state.workerBusy = false;
+    state.workerStats.drawn += Math.max(0, Number(data.repeat) || 0);
+    state.workerStats.lastDrawMs = Math.max(0, Number(data.drawMs) || 0);
+    pumpWorkerColumn(state);
+  } else if (data.type === 'error') {
+    restartWorker(state);
   } else if (data.type === 'dbg' && state._dbgEnabled) {
     console.debug('[spectro worker]', data);
   }
 }
 
-function sendColumnToWorker(state, column) {
+function queueColumnForWorker(state, column, repeat = 1) {
-  if (!state.worker || !column) return;
+  if (!column) return;
-  
+  const requested = Math.max(1, Math.floor(Number(repeat) || 1));
-  // Prüfe ob Worker bereit ist und nicht überlastet
+  if (state.pendingWorkerColumn) {
-  if (!state.workerReady) return;
+    state.pendingWorkerDropped += 1;
-
+    state.workerStats.dropped += 1;
-  try {
+  }
-    state.worker.postMessage({ type: 'column', data: column }, [column.buffer]);
+  state.pendingWorkerColumn = column;
-  } catch (e) {
+  state.pendingWorkerRepeat = Math.min(
-    state.useWorker = false;
+    Math.max(1, state.offscreenWidth || state.width || 1),
+    Math.max(0, state.pendingWorkerRepeat) + requested,
+  );
+  pumpWorkerColumn(state);
 }
-  advanceWriteIndex(state);
 
-  // Debug: alle ~1s senden wir ein Status-Log
+function pumpWorkerColumn(state) {
+  if (!state.worker || !state.workerReady || state.workerBusy || !state.pendingWorkerColumn) return;
+  const column = state.pendingWorkerColumn;
+  const repeat = Math.min(MAX_SCROLL_COLUMNS_PER_DRAW, Math.max(1, state.pendingWorkerRepeat || 1));
+  const dropped = Math.max(0, state.pendingWorkerDropped || 0);
+  state.pendingWorkerColumn = null;
+  // A large value means the display was suspended or overloaded. Never catch
+  // up for seconds; jump by a bounded amount and continue with live data.
+  state.pendingWorkerRepeat = 0;
+  state.pendingWorkerDropped = 0;
+  state.workerBusy = true;
+  state.workerMessageId += 1;
+  const id = state.workerMessageId;
+  try {
+    state.worker.postMessage({ type: 'column', id, data: column, repeat, dropped }, [column.buffer]);
+    state.workerStats.sent += repeat;
+  } catch (e) {
+    restartWorker(state);
+    return;
+  }
+  clearWorkerWatchdog(state);
+  state.workerWatchdog = setTimeout(() => {
+    if (!state.workerBusy || id !== state.workerMessageId) return;
+    restartWorker(state);
+  }, WORKER_WATCHDOG_MS);
+
   if (state._dbgEnabled && performance.now() >= state._dbgNextLog) {
     state._dbgNextLog = performance.now() + 1000;
-    console.debug('[spectro main] sent column', { writeIndex: state.writeIndex });
+    console.debug('[spectro]', { ...state.workerStats, busy: state.workerBusy, queuedRepeat: state.pendingWorkerRepeat });
   }
 }
 
+function clearWorkerWatchdog(state) {
+  if (!state.workerWatchdog) return;
+  clearTimeout(state.workerWatchdog);
+  state.workerWatchdog = null;
+}
+
+function restartWorker(state) {
+  clearWorkerWatchdog(state);
+  if (state.worker) {
+    try { state.worker.terminate(); } catch (_) {}
+  }
+  state.worker = null;
+  state.workerReady = false;
+  state.workerBusy = false;
+  state.workerStats.restarts += 1;
+  removeSpectroCanvasElement(state);
+}
+
 function ensureFallbackBuffers(state, width, height, fillDb, g) {
   const needsInit = !state.history ||
     state.width !== width ||
@@ -527,6 +601,23 @@ function resolveScrollRate(CONFIG) {
   return 1;
 }
 
+export function stepScrollAccumulator(accumulator, rate, frameDelta = 1) {
+  const safeAccumulator = Number.isFinite(Number(accumulator)) ? Math.max(0, Number(accumulator)) : 0;
+  const safeRate = Number.isFinite(Number(rate)) ? Math.max(0.01, Math.min(64, Number(rate))) : 1;
+  const safeDelta = Number.isFinite(Number(frameDelta)) ? Math.max(1, Math.floor(Number(frameDelta))) : 1;
+  const total = safeAccumulator + safeRate * safeDelta;
+  const columns = Math.floor(total + 1e-9);
+  return { columns, accumulator: Math.max(0, total - columns) };
+}
+
+export function spectrogramPixelsPerSourceFrame(rate, sampleRate, fftSize) {
+  const safeRate = [0.5, 1, 2, 4, 6].includes(Number(rate)) ? Number(rate) : 1;
+  const safeSampleRate = Math.max(8000, Number(sampleRate) || 48000);
+  const safeFftSize = Math.max(1024, Math.floor(Number(fftSize) || 4096));
+  const hopSamples = Math.max(128, Math.floor(safeFftSize / 8));
+  return BASE_SCROLL_CSS_PX_PER_SECOND * safeRate * hopSamples / safeSampleRate;
+}
+
 function advanceWriteIndex(state) {
   const width = Math.max(1, state.width || 1);
   state.writeIndex = (state.writeIndex + 1) % width;

www/workers/spectrogram.worker.js

@@ -1,9 +1,7 @@
-// workers/spectrogram.worker.js
+// Incremental OffscreenCanvas renderer for the spectrogram.
-// Handles Spectrogram rendering off the main thread using OffscreenCanvas.
+// One message is processed at a time and acknowledged. The sender therefore
+// never needs to build an unbounded postMessage queue.
 
-const FRAME_INTERVAL_MS = 1000 / 24;
-const MAX_QUEUE_AGE_MS = 2000; // wenn länger nichts geflossen ist, trotzdem zeichnen
-const MAX_PENDING_COLUMNS = 64;
 const LUT_SIZE = 256;
 const COLOR_STOPS = [
   { t: 0.0, color: [0, 0, 0] },
@@ -13,9 +11,6 @@ const COLOR_STOPS = [
   { t: 1.0, color: [255, 255, 255] },
 ];
 
-// Pre-calculated constants for performance
-const LUT_SIZE_MINUS_ONE = LUT_SIZE - 1;
-
 const state = {
   canvas: null,
   ctx: null,
@@ -24,33 +19,27 @@ const state = {
   topDb: -9,
   bottomDb: -90,
   gamma: 0.9,
-  fMin: 20,
-  fMax: 20000,
-  history: null,
-  writeIndex: 0,
-  imgData: null,
-  pixels: null,
   lut: null,
-  lastDraw: 0,
+  stripe: null,
-  drawTimer: null,
+  stripePixels: null,
-  pendingQueue: [],
+  drawn: 0,
-  lastColumnTs: 0,
+  dropped: 0,
 };
 
 self.onmessage = (event) => {
-  const data = event.data || {};
+  const message = event.data || {};
-  switch (data.type) {
+  switch (message.type) {
     case 'init':
-      handleInit(data);
+      init(message);
       break;
     case 'resize':
-      handleResize(data);
+      resize(message);
       break;
     case 'config':
-      handleConfig(data);
+      configure(message);
       break;
     case 'column':
-      handleColumn(data);
+      drawColumn(message);
       break;
     case 'dispose':
       dispose();
@@ -60,221 +49,155 @@ self.onmessage = (event) => {
   }
 };
 
-function handleInit({ canvas, width, height, topDb, bottomDb, gamma, fMin, fMax }) {
+function init({ canvas, width, height, topDb, bottomDb, gamma }) {
   if (!canvas) return;
-  
   state.canvas = canvas;
   state.ctx = canvas.getContext('2d', { alpha: false, desynchronized: true });
-  
   if (!state.ctx) {
-    postMessage({ type: 'error', error: 'ctx' });
+    postMessage({ type: 'error', error: '2d-context' });
     return;
   }
-  
   state.ctx.imageSmoothingEnabled = false;
-  state.topDb = Number.isFinite(topDb) ? topDb : state.topDb;
+  applyConfig(topDb, bottomDb, gamma);
-  state.bottomDb = Number.isFinite(bottomDb) ? bottomDb : state.bottomDb;
+  allocate(width, height);
-  state.fMin = Number.isFinite(fMin) ? fMin : state.fMin;
+  clearCanvas();
-  state.fMax = Number.isFinite(fMax) ? fMax : state.fMax;
-  state.gamma = clampGamma(gamma);
-  
-  allocateBuffers(width, height);
-  rebuildLut();
-  
   postMessage({ type: 'ready' });
 }
 
-function handleResize({ width, height, fMin, fMax }) {
+function resize({ width, height }) {
-  if (!state.canvas || !state.ctx) return;
+  if (!state.ctx) return;
-  if (!Number.isFinite(width) || !Number.isFinite(height) || width <= 0 || height <= 0) return;
+  const nextWidth = positiveInt(width, state.width || 1);
-  
+  const nextHeight = positiveInt(height, state.height || 1);
-  allocateBuffers(width, height);
+  if (nextWidth === state.width && nextHeight === state.height) return;
-  
+  allocate(nextWidth, nextHeight);
-  if (Number.isFinite(fMin)) state.fMin = fMin;
+  clearCanvas();
-  if (Number.isFinite(fMax)) state.fMax = fMax;
+  postMessage({ type: 'resized', width: state.width, height: state.height });
 }
 
-function handleConfig({ topDb, bottomDb, gamma }) {
+function configure({ topDb, bottomDb, gamma }) {
-  if (Number.isFinite(topDb)) state.topDb = topDb;
+  const before = `${state.topDb}|${state.bottomDb}|${state.gamma}`;
-  if (Number.isFinite(bottomDb)) state.bottomDb = bottomDb;
+  applyConfig(topDb, bottomDb, gamma);
-  if (Number.isFinite(gamma)) state.gamma = clampGamma(gamma);
+  const after = `${state.topDb}|${state.bottomDb}|${state.gamma}`;
-  rebuildLut();
+  if (before !== after) {
-}
+    // Old pixels use the previous colour transfer function. Clearing avoids a
-
+    // misleading mixed scale after a range/gamma change.
-function handleColumn({ data }) {
+    clearCanvas();
-  if (!data || !(data instanceof Float32Array)) return;
-  
-  if (!state.history || state.height !== data.length) {
-    allocateBuffers(state.width, data.length);
-  }
-
-  // Ringpuffer: halte nur die letzten wenige Columns, neueste gewinnt
-  state.pendingQueue.push(data);
-  while (state.pendingQueue.length > MAX_PENDING_COLUMNS) state.pendingQueue.shift();
-  state.lastColumnTs = performance.now();
-  maybeDraw();
-}
-
-function allocateBuffers(width, height) {
-  const clampedWidth = Math.max(1, Math.floor(width));
-  const clampedHeight = Math.max(1, Math.floor(height));
-  
-  // Vermeide unnötige Re-allokation
-  if (state.history && 
-      state.width === clampedWidth && 
-      state.height === clampedHeight) {
-    return; // Keine Größenänderung, behalte bestehende Buffers
-  }
-  
-  state.width = clampedWidth;
-  state.height = clampedHeight;
-  
-  if (state.canvas) {
-    state.canvas.width = clampedWidth;
-    state.canvas.height = clampedHeight;
-  }
-  
-  // Allokiere neuen Buffer nur wenn nötig
-  const neededSize = clampedWidth * clampedHeight;
-  if (!state.history || state.history.length !== neededSize) {
-    state.history = new Float32Array(neededSize);
-  }
-  state.history.fill(state.bottomDb);
-  
-  state.writeIndex = 0;
-  
-  if (state.ctx) {
-    state.imgData = state.ctx.createImageData(clampedWidth, clampedHeight);
-    state.pixels = state.imgData.data;
   }
 }
 
-function rebuildLut() {
+function applyConfig(topDb, bottomDb, gamma) {
-  state.lut = buildLut(LUT_SIZE);
+  if (Number.isFinite(topDb)) state.topDb = Number(topDb);
+  if (Number.isFinite(bottomDb)) state.bottomDb = Number(bottomDb);
+  if (state.topDb <= state.bottomDb) state.topDb = state.bottomDb + 1;
+  if (Number.isFinite(gamma)) state.gamma = clamp(Number(gamma), 0.3, 1.2);
+  state.lut = buildLut();
 }
 
-function maybeDraw() {
+function allocate(width, height) {
-  if (!state.ctx || !state.imgData || !state.history) return;
+  state.width = positiveInt(width, 1);
-  
+  state.height = positiveInt(height, 1);
-  const now = performance.now();
+  state.canvas.width = state.width;
-  const delta = now - state.lastDraw;
+  state.canvas.height = state.height;
-
+  state.stripe = null;
-  const tooLongNoColumn = state.lastColumnTs && (now - state.lastColumnTs > MAX_QUEUE_AGE_MS);
+  state.stripePixels = null;
-  const readyToDraw = delta >= FRAME_INTERVAL_MS || tooLongNoColumn;
-
-  if (readyToDraw) {
-    if (drawFrame()) {
-      state.lastDraw = now;
 }
-  } else if (!state.drawTimer) {
+
-    state.drawTimer = setTimeout(() => {
+function clearCanvas() {
-      state.drawTimer = null;
+  if (!state.ctx) return;
-      if (drawFrame()) {
+  state.ctx.save();
-        state.lastDraw = performance.now();
+  state.ctx.globalCompositeOperation = 'copy';
+  state.ctx.fillStyle = '#000';
+  state.ctx.fillRect(0, 0, state.width, state.height);
+  state.ctx.restore();
+}
+
+function drawColumn({ id, data, repeat = 1, dropped = 0 }) {
+  const started = performance.now();
+  if (!state.ctx || !(data instanceof Float32Array) || !data.length) {
+    postMessage({ type: 'drawn', id, drawMs: 0, repeat: 0, error: 'invalid-column' });
+    return;
+  }
+
+  const shift = Math.min(state.width, Math.max(1, Math.floor(Number(repeat) || 1)));
+  ensureStripe(shift);
+  colourStripe(data, shift);
+
+  if (shift < state.width) {
+    // Canvas-to-self copy is defined as if the source were captured before the
+    // draw, so overlapping left shifts do not smear the image.
+    state.ctx.drawImage(
+      state.canvas,
+      shift, 0, state.width - shift, state.height,
+      0, 0, state.width - shift, state.height,
+    );
+  }
+  state.ctx.putImageData(state.stripe, state.width - shift, 0);
+  state.drawn += shift;
+  state.dropped += Math.max(0, Number(dropped) || 0);
+
+  postMessage({
+    type: 'drawn',
+    id,
+    repeat: shift,
+    drawMs: performance.now() - started,
+    drawn: state.drawn,
+    dropped: state.dropped,
+  });
+}
+
+function ensureStripe(width) {
+  if (state.stripe && state.stripe.width === width && state.stripe.height === state.height) return;
+  state.stripe = state.ctx.createImageData(width, state.height);
+  state.stripePixels = state.stripe.data;
+}
+
+function colourStripe(column, stripeWidth) {
+  const pixels = state.stripePixels;
+  const range = Math.max(1e-6, state.topDb - state.bottomDb);
+  const sourceLast = Math.max(0, column.length - 1);
+  const targetLast = Math.max(1, state.height - 1);
+
+  for (let targetY = 0; targetY < state.height; targetY++) {
+    // Source columns are low-to-high frequency; canvas rows are top-to-bottom.
+    const sourcePos = (state.height - 1 - targetY) * sourceLast / targetLast;
+    const lo = Math.floor(sourcePos);
+    const hi = Math.min(sourceLast, lo + 1);
+    const frac = sourcePos - lo;
+    const a = finiteOr(column[lo], state.bottomDb);
+    const b = finiteOr(column[hi], a);
+    const db = a + (b - a) * frac;
+    const norm = Math.pow(clamp((db - state.bottomDb) / range, 0, 1), state.gamma);
+    const lutIndex = Math.min(LUT_SIZE - 1, Math.round(norm * (LUT_SIZE - 1))) * 3;
+
+    for (let x = 0; x < stripeWidth; x++) {
+      const pixel = (targetY * stripeWidth + x) * 4;
+      pixels[pixel] = state.lut[lutIndex];
+      pixels[pixel + 1] = state.lut[lutIndex + 1];
+      pixels[pixel + 2] = state.lut[lutIndex + 2];
+      pixels[pixel + 3] = 255;
     }
-    }, FRAME_INTERVAL_MS - delta);
   }
 }
 
-function drawFrame() {
+function buildLut() {
-  if (!state.ctx || !state.imgData || !state.history || !state.lut) return false;
+  const lut = new Uint8ClampedArray(LUT_SIZE * 3);
-  if (!flushPendingColumn()) return false;
+  for (let index = 0; index < LUT_SIZE; index++) {
-  
+    const [r, g, b] = colorFromStops(index / (LUT_SIZE - 1));
-  const { width, height, history, pixels, imgData } = state;
+    const offset = index * 3;
-  const range = Math.max(1e-3, state.topDb - state.bottomDb);
+    lut[offset] = r;
-  const lut = state.lut;
-  const base = state.writeIndex;
-  
-  const invertedHeight = height - 1;
-  
-  for (let x = 0; x < width; x++) {
-    const srcX = (base + x) % width;
-    const srcXOffset = srcX;
-    
-    for (let y = 0; y < height; y++) {
-      const dB = history[y * width + srcXOffset];
-      const clamped = dB < state.bottomDb ? state.bottomDb : 
-                     dB > state.topDb ? state.topDb : dB;
-      
-      let norm = (clamped - state.bottomDb) / range;
-      norm = norm < 0 ? 0 : norm > 1 ? 1 : norm;
-      norm = Math.pow(norm, state.gamma);
-      
-      const lutIdx = Math.min(LUT_SIZE_MINUS_ONE, Math.round(norm * LUT_SIZE_MINUS_ONE));
-      const destY = invertedHeight - y;
-      const pixelIndex = (destY * width + x) * 4;
-      const lutOffset = lutIdx * 3;
-      
-      pixels[pixelIndex + 0] = lut[lutOffset + 0];
-      pixels[pixelIndex + 1] = lut[lutOffset + 1];
-      pixels[pixelIndex + 2] = lut[lutOffset + 2];
-      pixels[pixelIndex + 3] = 255;
-    }
-  }
-  
-  state.ctx.putImageData(imgData, 0, 0);
-  return true;
-}
-
-function flushPendingColumn() {
-  if (!state.pendingQueue.length || !state.history) return false;
-
-  const width = state.width;
-  const height = state.height;
-  let writeIdx = state.writeIndex;
-  const hist = state.history;
-
-  while (state.pendingQueue.length) {
-    const column = state.pendingQueue.shift();
-    if (!column) continue;
-    const col = (column.length === height)
-      ? column
-      : normalizeColumn(column, height, state.bottomDb);
-    for (let y = 0; y < height; y++) {
-      const value = col[y];
-      hist[y * width + writeIdx] = Number.isFinite(value) ? value : state.bottomDb;
-    }
-    writeIdx = (writeIdx + 1) % width;
-  }
-
-  state.writeIndex = writeIdx;
-  return true;
-}
-
-function normalizeColumn(column, targetHeight, fillDb) {
-  const adjusted = new Float32Array(targetHeight);
-  const copyLength = Math.min(column.length, targetHeight);
-  adjusted.set(column.subarray(0, copyLength));
-  adjusted.fill(fillDb, copyLength);
-  return adjusted;
-}
-
-function buildLut(size) {
-  const lut = new Uint8ClampedArray(size * 3);
-  const sizeMinusOne = size - 1;
-  
-  for (let i = 0; i < size; i++) {
-    const t = i / sizeMinusOne;
-    const [r, g, b] = colorFromStops(t);
-    const offset = i * 3;
-    lut[offset + 0] = r;
     lut[offset + 1] = g;
     lut[offset + 2] = b;
   }
-  
   return lut;
 }
 
-function colorFromStops(tValue) {
+function colorFromStops(value) {
-  const t = tValue < 0 ? 0 : tValue > 1 ? 1 : tValue;
+  const t = clamp(value, 0, 1);
-  
+  for (let index = 1; index < COLOR_STOPS.length; index++) {
-  for (let i = 1; i < COLOR_STOPS.length; i++) {
+    const left = COLOR_STOPS[index - 1];
-    const left = COLOR_STOPS[i - 1];
+    const right = COLOR_STOPS[index];
-    const right = COLOR_STOPS[i];
-    
     if (t <= right.t) {
-      const span = right.t - left.t || 1;
+      const rel = (t - left.t) / Math.max(1e-9, right.t - left.t);
-      const rel = (t - left.t) / span;
       return [
         Math.round(left.color[0] + rel * (right.color[0] - left.color[0])),
         Math.round(left.color[1] + rel * (right.color[1] - left.color[1])),
@@ -282,41 +205,27 @@ function colorFromStops(tValue) {
       ];
     }
   }
-  
+  return COLOR_STOPS[COLOR_STOPS.length - 1].color.slice();
-  const last = COLOR_STOPS[COLOR_STOPS.length - 1].color;
-  return [last[0], last[1], last[2]];
 }
 
-function clampGamma(value) {
+function positiveInt(value, fallback) {
-  if (!Number.isFinite(value)) return 0.9;
+  const number = Math.floor(Number(value));
-  if (value < 0.3) return 0.3;
+  return Number.isFinite(number) && number > 0 ? number : fallback;
-  if (value > 1.2) return 1.2;
+}
-  return value;
+
+function finiteOr(value, fallback) {
+  return Number.isFinite(value) ? value : fallback;
+}
+
+function clamp(value, min, max) {
+  return value < min ? min : value > max ? max : value;
 }
 
 function dispose() {
-  if (state.drawTimer) {
+  state.stripe = null;
-    clearTimeout(state.drawTimer);
+  state.stripePixels = null;
-    state.drawTimer = null;
-  }
-  
-  if (state.history) {
-    state.history = null;
-  }
-  if (state.imgData) {
-    state.imgData = null;
-  }
-  if (state.pixels) {
-    state.pixels = null;
-  }
-  if (state.lut) {
   state.lut = null;
-  }
-  state.pendingColumn = null;
   state.canvas = null;
   state.ctx = null;
-  
+  if (typeof self.close === 'function') self.close();
-  if (typeof self.close === 'function') {
-    try { self.close(); } catch (_) {}
-  }
 }