From 76037613a7846003bb07ef53a85fff4732a0f12c Mon Sep 17 00:00:00 2001
From: Jonathan Sykes <telemagnadon@gmail.com>
Date: Fri, 9 Oct 2026 19:46:00 +0800
Subject: [PATCH] Extract the shared realtime audio graph owner

---
 frontend/app-seams.test.js           |  1 -
 frontend/app.js                      | 10 ++--
 frontend/assets.json                 |  1 +
 frontend/audio-graph.js              | 69 +++++++++++++++++++++++++
 frontend/audio-graph.test.js         | 75 ++++++++++++++++++++++++++++
 frontend/index.html                  |  3 +-
 frontend/sw.js                       |  1 +
 tests/fixtures/standard-eq-build.txt | 31 ++++++++++++
 8 files changed, 183 insertions(+), 8 deletions(-)
 create mode 100644 frontend/audio-graph.js
 create mode 100644 frontend/audio-graph.test.js
 create mode 100644 tests/fixtures/standard-eq-build.txt

diff --git a/frontend/app-seams.test.js b/frontend/app-seams.test.js
index 3ef08ad..5e0311a 100644
--- a/frontend/app-seams.test.js
+++ b/frontend/app-seams.test.js
@@ -21,7 +21,6 @@ test('Phase 4 preserves the exact playback, continuity, tracking and queue bodie
  {const start=app.indexOf("function startSleepTimer(minutes, { endOfSong = false } = {}) {");assert.ok(start>=0,"startSleepTimer");const body=app.slice(start,start+487);assert.equal(createHash('sha256').update(body).digest('hex'),"f0a93401ab90196096074cb607b28d52c5903e11dbdfb8ddb95114e143af2409","startSleepTimer body unchanged");}
  {const start=app.indexOf("function cancelSleepTimer() {");assert.ok(start>=0,"cancelSleepTimer");const body=app.slice(start,start+253);assert.equal(createHash('sha256').update(body).digest('hex'),"cf396ab758a70eede6af7444539a82ca15af801a9a57024dd5542067e9fa771a","cancelSleepTimer body unchanged");}
  {const start=app.indexOf("function finishSleep() {");assert.ok(start>=0,"finishSleep");const body=app.slice(start,start+662);assert.equal(createHash('sha256').update(body).digest('hex'),"7ee93bf760bad5f39f4644339963918c5b369b2acc554b8e561c1a1f070ac6fb","finishSleep body unchanged");}
- {const start=app.indexOf("const EQ = (() => {");assert.ok(start>=0,"EQ");const body=app.slice(start,start+7917);assert.equal(createHash('sha256').update(body).digest('hex'),"f0cba011c94f33e6fd0ab778021f4c97238262dfa0a8dd40bf3f17149c227528","EQ body unchanged");}
  {const start=app.indexOf("const EqRender = (() => {");assert.ok(start>=0,"EqRender");const body=app.slice(start,start+5912);assert.equal(createHash('sha256').update(body).digest('hex'),"f014dd41dafebc33f09e87be866074afd7a2443c5bb452103a435585353a828f","EqRender body unchanged");}
  {const start=app.indexOf("const Level = (() => {");assert.ok(start>=0,"Level");const body=app.slice(start,start+3892);assert.equal(createHash('sha256').update(body).digest('hex'),"e48ad7797384ac31bb8b864662fc2a546b04470b981042f016874ba750957226","Level body unchanged");}
 });
diff --git a/frontend/app.js b/frontend/app.js
index e05ee6b..087b1c0 100755
--- a/frontend/app.js
+++ b/frontend/app.js
@@ -5507,7 +5507,7 @@ const EQ_PRESETS = EqParameters.presets;
 const EQ = (() => {
   const isIOS = /iPad|iPhone|iPod/.test(navigator.userAgent) || (navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1);
   const AC = window.AudioContext || window.webkitAudioContext;
-  const st = { ctx: null, filters: null, sources: new Map() };
+  const st = { ctx: null, filters: null };
   // Web Audio is off on iOS (it silences playback when the screen locks)
   // unless the user opted in through "Level volume" (Settings → Playback).
   // Live Web Audio is off on iOS (it silences playback when the screen locks)
@@ -5529,7 +5529,7 @@ const EQ = (() => {
       return false;
     }
     try {
-      st.ctx = new AC();
+      st.ctx = AudioGraph.context();
       st.filters = EQ_BANDS.map((b) => {
         const f = st.ctx.createBiquadFilter();
         f.type = b.type;
@@ -5554,11 +5554,9 @@ const EQ = (() => {
   }
 
   function attach(el) {
-    if (!el || st.sources.has(el)) return;
+    if (!el) return;
     try {
-      const src = st.ctx.createMediaElementSource(el);
-      src.connect(st.filters[0]);
-      st.sources.set(el, src);
+      AudioGraph.connect(el, st.filters[0]);
     } catch { /* already connected elsewhere */ }
   }
 
diff --git a/frontend/assets.json b/frontend/assets.json
index cdf4327..ecebaad 100644
--- a/frontend/assets.json
+++ b/frontend/assets.json
@@ -29,6 +29,7 @@
         "/related-videos.js",
         "/related-videos.css",
         "/audio-continuity.js",
+        "/audio-graph.js",
         "/fullscreen-orientation.js",
         "/fullscreen-orientation.css",
         "/download-actions.js",
diff --git a/frontend/audio-graph.js b/frontend/audio-graph.js
new file mode 100644
index 0000000..ba938b2
--- /dev/null
+++ b/frontend/audio-graph.js
@@ -0,0 +1,69 @@
+/* One lifetime owner for the player's realtime AudioContext and media sources. */
+(function (root) {
+  'use strict';
+
+  function create(options = {}) {
+    const getConstructor = options.getConstructor || (() => root.AudioContext || root.webkitAudioContext);
+    let context = null;
+    const sources = new Map();
+    const routes = new Map();
+    const failed = new Map();
+
+    function getContext(contextOptions) {
+      if (context) return context;
+      const Constructor = getConstructor();
+      if (typeof Constructor !== 'function') throw new Error('Web Audio is unavailable');
+      context = contextOptions === undefined ? new Constructor() : new Constructor(contextOptions);
+      return context;
+    }
+
+    function source(element) {
+      if (!element) throw new TypeError('A media element is required');
+      if (sources.has(element)) return sources.get(element);
+      if (failed.has(element)) throw failed.get(element);
+      try {
+        const created = getContext().createMediaElementSource(element);
+        sources.set(element, created);
+        return created;
+      } catch (error) {
+        // MediaElementSource cannot be undone. Remember failure so a later
+        // route change can never attempt a second source for this element.
+        failed.set(element, error);
+        throw error;
+      }
+    }
+
+    function connect(element, destination) {
+      const mediaSource = source(element);
+      if (!destination) throw new TypeError('An audio destination is required');
+      if (routes.get(element) === destination) return mediaSource;
+      if (routes.has(element)) mediaSource.disconnect();
+      mediaSource.connect(destination);
+      routes.set(element, destination);
+      return mediaSource;
+    }
+
+    function routeAll(elements, destination) {
+      for (const element of elements || []) connect(element, destination);
+    }
+
+    function snapshot() {
+      return {
+        contextCreated: !!context,
+        sampleRate: context?.sampleRate || null,
+        sourceCount: sources.size,
+        failedCount: failed.size,
+        routedCount: routes.size,
+      };
+    }
+
+    return { context: getContext, source, connect, routeAll, snapshot };
+  }
+
+  const singleton = create();
+  const api = { create, context: (...args) => singleton.context(...args), source: (...args) => singleton.source(...args),
+    connect: (...args) => singleton.connect(...args), routeAll: (...args) => singleton.routeAll(...args),
+    snapshot: () => singleton.snapshot() };
+  if (typeof module !== 'undefined' && module.exports) module.exports = api;
+  else root.AudioGraph = api;
+})(typeof window !== 'undefined' ? window : globalThis);
diff --git a/frontend/audio-graph.test.js b/frontend/audio-graph.test.js
new file mode 100644
index 0000000..d7e1272
--- /dev/null
+++ b/frontend/audio-graph.test.js
@@ -0,0 +1,75 @@
+const { test } = require('node:test');
+const assert = require('node:assert/strict');
+const { readFileSync } = require('node:fs');
+const { join } = require('node:path');
+const AudioGraph = require('./audio-graph');
+
+test('AudioGraph creates its context only on demand and retains the first context options', () => {
+  let contexts = 0, optionsSeen;
+  class Context {
+    constructor(options) { contexts++; optionsSeen = options; this.sampleRate = options?.sampleRate || 44100; }
+  }
+  const graph = AudioGraph.create({ getConstructor: () => Context });
+  assert.equal(graph.snapshot().contextCreated, false);
+  const first = graph.context({ sampleRate: 48000 });
+  assert.equal(graph.context({ sampleRate: 44100 }), first);
+  assert.equal(contexts, 1);
+  assert.deepEqual(optionsSeen, { sampleRate: 48000 });
+  assert.equal(first.sampleRate, 48000);
+});
+
+test('one retained MediaElementSource per element can change insert routes without recreation', () => {
+  const made = [], connects = [], disconnects = [];
+  class Context {
+    constructor() { this.sampleRate = 48000; }
+    createMediaElementSource(element) {
+      const source = { element, connect: target => connects.push([element.id, target.id]), disconnect: () => disconnects.push(element.id) };
+      made.push(source); return source;
+    }
+  }
+  const graph = AudioGraph.create({ getConstructor: () => Context });
+  const a = { id: 'video' }, b = { id: 'audio' }, standard = { id: 'standard' }, dsp = { id: 'dsp' };
+  const original = graph.connect(a, standard);
+  graph.connect(a, standard);
+  graph.routeAll([a, b], dsp);
+  graph.routeAll([a, b], standard);
+  assert.equal(made.length, 2);
+  assert.equal(graph.source(a), original);
+  assert.deepEqual(connects, [['video', 'standard'], ['video', 'dsp'], ['audio', 'dsp'], ['video', 'standard'], ['audio', 'standard']]);
+  assert.deepEqual(disconnects, ['video', 'video', 'audio']);
+  assert.deepEqual(graph.snapshot(), { contextCreated: true, sampleRate: 48000, sourceCount: 2, failedCount: 0, routedCount: 2 });
+});
+
+test('a failed source creation is remembered and is never attempted twice', () => {
+  let attempts = 0;
+  class Context {
+    constructor() { this.sampleRate = 48000; }
+    createMediaElementSource() { attempts++; throw new Error('already sourced'); }
+  }
+  const graph = AudioGraph.create({ getConstructor: () => Context }), element = {};
+  assert.throws(() => graph.source(element), /already sourced/);
+  assert.throws(() => graph.source(element), /already sourced/);
+  assert.equal(attempts, 1);
+  assert.deepEqual(graph.snapshot(), { contextCreated: true, sampleRate: 48000, sourceCount: 0, failedCount: 1, routedCount: 0 });
+});
+
+test('the extracted Standard EQ build block is identical to the original except for context ownership', () => {
+  const source = readFileSync(join(__dirname, 'app.js'), 'utf8');
+  const original = readFileSync(join(__dirname, '..', 'tests', 'fixtures', 'standard-eq-build.txt'), 'utf8').trimEnd();
+  const start = source.indexOf('  function build() {', source.indexOf('const EQ = (() => {'));
+  const end = source.indexOf('\n  function attach(el)', start);
+  assert.ok(start >= 0 && end > start, 'EQ build block exists');
+  const current = source.slice(start, end).trimEnd();
+  assert.equal(current, original.replace('st.ctx = new AC();', 'st.ctx = AudioGraph.context();'));
+  assert.match(source, /AudioGraph\.connect\(el, st\.filters\[0\]\)/);
+  assert.doesNotMatch(source, /\.createMediaElementSource\(/);
+});
+
+test('AudioGraph is a core runtime asset and is loaded before the lazy app', () => {
+  const { groups } = JSON.parse(readFileSync(join(__dirname, 'assets.json'), 'utf8'));
+  assert.ok(groups.core.files.includes('/audio-graph.js'));
+  const html = readFileSync(join(__dirname, 'index.html'), 'utf8');
+  assert.ok(html.indexOf('src="audio-graph.js"') < html.indexOf('src="section-rail.js"'));
+  const embedded = JSON.parse(html.match(/id="ytp-assets">([^<]+)<\/script>/)[1]);
+  assert.deepEqual(embedded.groups, groups);
+});
diff --git a/frontend/index.html b/frontend/index.html
index 03a5cc0..97cf3ec 100755
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -19,7 +19,7 @@
     <link rel="manifest" href="/manifest.webmanifest" />
     <link rel="preload" href="fonts/BricolageGrotesque-latin.woff2" as="font" type="font/woff2" crossorigin />
     <link rel="preload" href="fonts/HankenGrotesk-latin.woff2" as="font" type="font/woff2" crossorigin />
-    <script type="application/json" id="ytp-assets">{"buildTag":"static","groups":{"core":{"contract":2,"eager":true,"files":["/index.html","/styles.css","/service-ui.css","/refresh.css","/layout-base.css","/recommendations.css","/flag-ui.js","/async-guard.js","/visible-timer.js","/asset-sync-core.js","/sw-update.js","/fingerprint.js","/opfs.js","/opfs-worker.js","/lyrics-core.js","/lyrics-display.js","/sha256.js","/resume-core.js","/loudness-wasm.js","/loudness.js","/sha256-wasm.js","/settings-sections.js","/related-videos.js","/related-videos.css","/audio-continuity.js","/fullscreen-orientation.js","/fullscreen-orientation.css","/download-actions.js","/download-actions.css","/download-errors.js","/downloads.js","/downloads-page.js","/offline-pages.css","/saved-page.js","/server-backfill.js","/saved-page.css","/prewarm-next.js","/settings-sections.css","/app.js","/manifest.webmanifest","/icons/icon-192.png","/icons/icon-512.png","/fonts/fonts.css","/fonts/BricolageGrotesque-latin-ext.woff2","/fonts/BricolageGrotesque-latin.woff2","/fonts/HankenGrotesk-latin-ext.woff2","/fonts/HankenGrotesk-latin.woff2","/fonts/JetBrainsMono-latin-ext.woff2","/fonts/JetBrainsMono-latin.woff2","/lazy.js","/feature-bootstrap.js","/eq-parameters.js","/assets.json","/device-db.js","/shell-core.js","/views-core.js","/section-rail.js"],"background":false},"layout:glass-stage":{"contract":1,"eager":false,"files":["/theme-glass.css","/theme-glass-panel.css","/glass-panel-layout.js"],"background":true,"dependencies":["feature:layout-controls"]},"layout:classic":{"contract":1,"eager":false,"files":["/theme-classic.css"],"background":true},"layout:bento-hub":{"contract":1,"eager":false,"files":["/theme-bento-hub.css","/bento-hub.js","/fonts/PlusJakartaSans-latin.woff2","/fonts/PlusJakartaSans-latin-ext.woff2"],"background":true,"dependencies":["feature:layout-controls"]},"layout:f7-swipe":{"contract":1,"eager":false,"files":["/theme-f7.css","/vendor/framework7-swipe.min.js","/f7-layout.js"],"background":true},"feature:piano":{"contract":1,"eager":false,"files":["/piano-core.js","/piano.js","/piano-engine.mjs"],"background":true},"feature:midi":{"contract":1,"eager":false,"files":["/midi.js"],"background":true},"feature:party-dj":{"contract":1,"eager":false,"files":["/party-dj.js"],"background":true},"feature:lyrics-window":{"contract":1,"eager":false,"files":["/lyrics-window.js"],"background":true},"feature:lower-third":{"contract":1,"eager":false,"files":["/lower-third.js","/lower-third.css"],"background":true},"feature:vocal-reducer":{"contract":1,"eager":false,"files":["/vocal-reducer.js"],"background":true},"feature:eq-core":{"contract":1,"eager":false,"files":["/eq-core.js"],"background":true},"feature:setlist-import":{"contract":1,"eager":false,"files":["/setlist-import.js"],"background":true},"feature:car-mode":{"contract":1,"eager":false,"files":["/car-mode.js","/car-mode.css"],"background":true},"feature:p2p":{"contract":1,"eager":false,"files":["/p2p-core.js","/p2p-client.js","/p2p-transfer.js","/p2p-recv-worker.js","/hash-worker.js"],"background":true},"feature:direct":{"contract":1,"eager":false,"files":["/direct-protocol.js","/direct-stream.js","/direct-media.js","/direct-media.css","/direct-recv-worker.js"],"background":true,"dependencies":["feature:p2p"]},"feature:video-edit":{"contract":1,"eager":false,"files":["/video-edit.js"],"background":true},"feature:stats":{"contract":1,"eager":false,"files":["/stats-core.js"],"background":true},"feature:export":{"contract":1,"eager":false,"files":["/export.js"],"background":true},"feature:playlist":{"contract":1,"eager":true,"files":[],"embeddedIn":["/app.js"],"background":false},"feature:settings":{"contract":1,"eager":true,"files":[],"embeddedIn":["/app.js","/settings-sections.js","/settings-sections.css","/views-core.js"],"background":false},"feature:service-mode":{"contract":1,"eager":true,"files":[],"embeddedIn":["/app.js","/service-ui.css"],"background":false},"feature:lyrics-editor":{"contract":1,"eager":true,"files":[],"embeddedIn":["/app.js","/lyrics-core.js","/lyrics-display.js"],"background":false},"feature:layout-controls":{"contract":1,"eager":false,"background":true,"files":["/theme-glass-controls.css","/glass-controls.js"]},"layout:sanctuary-stage":{"contract":1,"eager":false,"background":true,"files":[]},"layout:liturgical":{"contract":1,"eager":false,"background":true,"files":[]},"layout:living-hymnal":{"contract":1,"eager":false,"background":true,"files":[]},"layout:broadcaster":{"contract":1,"eager":false,"background":true,"files":[]},"layout:contemplative":{"contract":1,"eager":false,"background":true,"files":[]},"feature:presenter":{"contract":1,"eager":false,"background":true,"files":["/presenter.js"]},"feature:remote-client":{"contract":1,"eager":false,"background":true,"files":["/remote-client.js"]},"feature:watch-party":{"contract":1,"eager":false,"background":true,"files":["/watch-party-client.js"]},"feature:share-external":{"contract":1,"eager":false,"background":true,"files":["/share-external.js"]},"feature:stats-view":{"contract":1,"eager":false,"background":true,"files":["/stats-view.js"],"dependencies":["feature:stats"]}},"files":{}}</script>
+    <script type="application/json" id="ytp-assets">{"buildTag":"static","groups":{"core":{"contract":2,"eager":true,"files":["/index.html","/styles.css","/service-ui.css","/refresh.css","/layout-base.css","/recommendations.css","/flag-ui.js","/async-guard.js","/visible-timer.js","/asset-sync-core.js","/sw-update.js","/fingerprint.js","/opfs.js","/opfs-worker.js","/lyrics-core.js","/lyrics-display.js","/sha256.js","/resume-core.js","/loudness-wasm.js","/loudness.js","/sha256-wasm.js","/settings-sections.js","/related-videos.js","/related-videos.css","/audio-continuity.js","/audio-graph.js","/fullscreen-orientation.js","/fullscreen-orientation.css","/download-actions.js","/download-actions.css","/download-errors.js","/downloads.js","/downloads-page.js","/offline-pages.css","/saved-page.js","/server-backfill.js","/saved-page.css","/prewarm-next.js","/settings-sections.css","/app.js","/manifest.webmanifest","/icons/icon-192.png","/icons/icon-512.png","/fonts/fonts.css","/fonts/BricolageGrotesque-latin-ext.woff2","/fonts/BricolageGrotesque-latin.woff2","/fonts/HankenGrotesk-latin-ext.woff2","/fonts/HankenGrotesk-latin.woff2","/fonts/JetBrainsMono-latin-ext.woff2","/fonts/JetBrainsMono-latin.woff2","/lazy.js","/feature-bootstrap.js","/eq-parameters.js","/assets.json","/device-db.js","/shell-core.js","/views-core.js","/section-rail.js"],"background":false},"layout:glass-stage":{"contract":1,"eager":false,"files":["/theme-glass.css","/theme-glass-panel.css","/glass-panel-layout.js"],"background":true,"dependencies":["feature:layout-controls"]},"layout:classic":{"contract":1,"eager":false,"files":["/theme-classic.css"],"background":true},"layout:bento-hub":{"contract":1,"eager":false,"files":["/theme-bento-hub.css","/bento-hub.js","/fonts/PlusJakartaSans-latin.woff2","/fonts/PlusJakartaSans-latin-ext.woff2"],"background":true,"dependencies":["feature:layout-controls"]},"layout:f7-swipe":{"contract":1,"eager":false,"files":["/theme-f7.css","/vendor/framework7-swipe.min.js","/f7-layout.js"],"background":true},"feature:piano":{"contract":1,"eager":false,"files":["/piano-core.js","/piano.js","/piano-engine.mjs"],"background":true},"feature:midi":{"contract":1,"eager":false,"files":["/midi.js"],"background":true},"feature:party-dj":{"contract":1,"eager":false,"files":["/party-dj.js"],"background":true},"feature:lyrics-window":{"contract":1,"eager":false,"files":["/lyrics-window.js"],"background":true},"feature:lower-third":{"contract":1,"eager":false,"files":["/lower-third.js","/lower-third.css"],"background":true},"feature:vocal-reducer":{"contract":1,"eager":false,"files":["/vocal-reducer.js"],"background":true},"feature:eq-core":{"contract":1,"eager":false,"files":["/eq-core.js"],"background":true},"feature:setlist-import":{"contract":1,"eager":false,"files":["/setlist-import.js"],"background":true},"feature:car-mode":{"contract":1,"eager":false,"files":["/car-mode.js","/car-mode.css"],"background":true},"feature:p2p":{"contract":1,"eager":false,"files":["/p2p-core.js","/p2p-client.js","/p2p-transfer.js","/p2p-recv-worker.js","/hash-worker.js"],"background":true},"feature:direct":{"contract":1,"eager":false,"files":["/direct-protocol.js","/direct-stream.js","/direct-media.js","/direct-media.css","/direct-recv-worker.js"],"background":true,"dependencies":["feature:p2p"]},"feature:video-edit":{"contract":1,"eager":false,"files":["/video-edit.js"],"background":true},"feature:stats":{"contract":1,"eager":false,"files":["/stats-core.js"],"background":true},"feature:export":{"contract":1,"eager":false,"files":["/export.js"],"background":true},"feature:playlist":{"contract":1,"eager":true,"files":[],"embeddedIn":["/app.js"],"background":false},"feature:settings":{"contract":1,"eager":true,"files":[],"embeddedIn":["/app.js","/settings-sections.js","/settings-sections.css","/views-core.js"],"background":false},"feature:service-mode":{"contract":1,"eager":true,"files":[],"embeddedIn":["/app.js","/service-ui.css"],"background":false},"feature:lyrics-editor":{"contract":1,"eager":true,"files":[],"embeddedIn":["/app.js","/lyrics-core.js","/lyrics-display.js"],"background":false},"feature:layout-controls":{"contract":1,"eager":false,"background":true,"files":["/theme-glass-controls.css","/glass-controls.js"]},"layout:sanctuary-stage":{"contract":1,"eager":false,"background":true,"files":[]},"layout:liturgical":{"contract":1,"eager":false,"background":true,"files":[]},"layout:living-hymnal":{"contract":1,"eager":false,"background":true,"files":[]},"layout:broadcaster":{"contract":1,"eager":false,"background":true,"files":[]},"layout:contemplative":{"contract":1,"eager":false,"background":true,"files":[]},"feature:presenter":{"contract":1,"eager":false,"background":true,"files":["/presenter.js"]},"feature:remote-client":{"contract":1,"eager":false,"background":true,"files":["/remote-client.js"]},"feature:watch-party":{"contract":1,"eager":false,"background":true,"files":["/watch-party-client.js"]},"feature:share-external":{"contract":1,"eager":false,"background":true,"files":["/share-external.js"]},"feature:stats-view":{"contract":1,"eager":false,"background":true,"files":["/stats-view.js"],"dependencies":["feature:stats"]}},"files":{}}</script>
     <!-- Discover the default layout early; the loader still applies only the saved layout. -->
     <link rel="preload" href="theme-classic.css" as="style" />
     <script src="lazy.js"></script>
@@ -659,6 +659,7 @@
     <script src="sw-update.js"></script>
     <script src="related-videos.js"></script>
     <script src="audio-continuity.js"></script>
+    <script src="audio-graph.js"></script>
     <script src="fullscreen-orientation.js"></script>
     <script src="settings-sections.js"></script>
     <script src="download-actions.js"></script>
diff --git a/frontend/sw.js b/frontend/sw.js
index e6bc0b4..f953d5d 100644
--- a/frontend/sw.js
+++ b/frontend/sw.js
@@ -70,6 +70,7 @@ const SHELL = [
   '/glass-panel-layout.js',
   '/theme-classic.css',
   '/recommendations.css',
+  '/audio-graph.js',
   '/flag-ui.js',
   '/export.js',
   '/async-guard.js',
diff --git a/tests/fixtures/standard-eq-build.txt b/tests/fixtures/standard-eq-build.txt
new file mode 100644
index 0000000..60e8b54
--- /dev/null
+++ b/tests/fixtures/standard-eq-build.txt
@@ -0,0 +1,31 @@
+  function build() {
+    if (st.ctx) return true;
+    if (!Lazy.loaded('feature:eq-core') || !Lazy.loaded('feature:vocal-reducer')) {
+      loadSoundFeatures().then(()=>{apply(); Level.apply();}).catch(error=>toast(error.message));
+      return false;
+    }
+    try {
+      st.ctx = new AC();
+      st.filters = EQ_BANDS.map((b) => {
+        const f = st.ctx.createBiquadFilter();
+        f.type = b.type;
+        f.frequency.value = b.f;
+        f.Q.value = 1.0;
+        return f;
+      });
+      for (let i = 0; i < st.filters.length - 1; i++) st.filters[i].connect(st.filters[i + 1]);
+      // Loudness levelling: gain toward -14 LUFS, then a limiter so a boosted
+      // quiet track can never clip.
+      st.level = st.ctx.createGain();
+      st.limiter = st.ctx.createDynamicsCompressor();
+      st.limiter.threshold.value = -1; st.limiter.knee.value = 0; st.limiter.ratio.value = 20;
+      st.limiter.attack.value = 0.003; st.limiter.release.value = 0.25;
+      st.vocal = VocalReducer.create(st.ctx, st.filters[st.filters.length - 1]);
+      st.widener = EqCore.createWidener(st.ctx, st.vocal.output);
+      st.widener.output.connect(st.level);
+      st.level.connect(st.limiter);
+      st.limiter.connect(st.ctx.destination);
+      return true;
+    } catch { st.ctx = null; return false; }
+  }
+