From 8dbe151ddd930ce8f5dd0dd764b9a2413e80d9d6 Mon Sep 17 00:00:00 2001
From: Benjas333 <67520048+Benjas333@users.noreply.github.com>
Date: Fri, 5 Sep 2025 14:15:47 -0600
Subject: [PATCH] fix(audio-compressor): real-time behavior and duplicated
 audio bug (#3786)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 src/plugins/audio-compressor.ts | 137 ++++++++++++++++++++++++++++----
 1 file changed, 122 insertions(+), 15 deletions(-)

diff --git a/src/plugins/audio-compressor.ts b/src/plugins/audio-compressor.ts
index 1be10e89..ee2f4b46 100644
--- a/src/plugins/audio-compressor.ts
+++ b/src/plugins/audio-compressor.ts
@@ -1,26 +1,133 @@
 import { createPlugin } from '@/utils';
 import { t } from '@/i18n';
+import { type YoutubePlayer } from '@/types/youtube-player';
+
+const lazySafeTry = (...fns: (() => void)[]) => {
+  for (const fn of fns) {
+    try {
+      fn();
+    } catch {}
+  }
+};
+
+const createCompressorNode = (
+  audioContext: AudioContext,
+): DynamicsCompressorNode => {
+  const compressor = audioContext.createDynamicsCompressor();
+
+  compressor.threshold.value = -50;
+  compressor.ratio.value = 12;
+  compressor.knee.value = 40;
+  compressor.attack.value = 0;
+  compressor.release.value = 0.25;
+
+  return compressor;
+};
+
+class Storage {
+  lastSource: MediaElementAudioSourceNode | null = null;
+  lastContext: AudioContext | null = null;
+  lastCompressor: DynamicsCompressorNode | null = null;
+
+  connected: WeakMap<MediaElementAudioSourceNode, DynamicsCompressorNode> =
+    new WeakMap();
+
+  connectToCompressor = (
+    source: MediaElementAudioSourceNode | null = null,
+    audioContext: AudioContext | null = null,
+    compressor: DynamicsCompressorNode | null = null,
+  ): boolean => {
+    if (!(source && audioContext && compressor)) return false;
+
+    const current = this.connected.get(source);
+    if (current === compressor) return false;
+
+    this.lastSource = source;
+    this.lastContext = audioContext;
+    this.lastCompressor = compressor;
+
+    if (current) {
+      lazySafeTry(
+        () => source.disconnect(current),
+        () => current.disconnect(audioContext.destination),
+      );
+    } else {
+      lazySafeTry(() => source.disconnect(audioContext.destination));
+    }
+
+    try {
+      source.connect(compressor);
+      compressor.connect(audioContext.destination);
+      this.connected.set(source, compressor);
+      return true;
+    } catch (error) {
+      console.error('connectToCompressor failed', error);
+      return false;
+    }
+  };
+
+  disconnectCompressor = (): boolean => {
+    const source = this.lastSource;
+    const audioContext = this.lastContext;
+    if (!(source && audioContext)) return false;
+    const current = this.connected.get(source);
+    if (!current) return false;
+
+    lazySafeTry(
+      () => source.connect(audioContext.destination),
+      () => source.disconnect(current),
+      () => current.disconnect(audioContext.destination),
+    );
+    this.connected.delete(source);
+    return true;
+  };
+}
+
+const storage = new Storage();
+
+const audioCanPlayHandler = ({
+  detail: { audioSource, audioContext },
+}: CustomEvent<Compressor>) => {
+  storage.connectToCompressor(
+    audioSource,
+    audioContext,
+    createCompressorNode(audioContext),
+  );
+};
+
+const ensureAudioContextLoad = (playerApi: YoutubePlayer) => {
+  if (playerApi.getPlayerState() !== 1 || storage.lastContext) return;
+
+  playerApi.loadVideoById(
+    playerApi.getPlayerResponse().videoDetails.videoId,
+    playerApi.getCurrentTime(),
+    playerApi.getUserPlaybackQualityPreference(),
+  );
+};
 
 export default createPlugin({
   name: () => t('plugins.audio-compressor.name'),
   description: () => t('plugins.audio-compressor.description'),
 
-  renderer() {
-    document.addEventListener(
-      'ytmd:audio-can-play',
-      ({ detail: { audioSource, audioContext } }) => {
-        const compressor = audioContext.createDynamicsCompressor();
+  renderer: {
+    onPlayerApiReady(playerApi) {
+      ensureAudioContextLoad(playerApi);
+    },
 
-        compressor.threshold.value = -50;
-        compressor.ratio.value = 12;
-        compressor.knee.value = 40;
-        compressor.attack.value = 0;
-        compressor.release.value = 0.25;
+    start() {
+      document.addEventListener('ytmd:audio-can-play', audioCanPlayHandler, {
+        passive: true,
+      });
+      storage.connectToCompressor(
+        storage.lastSource,
+        storage.lastContext,
+        storage.lastCompressor,
+      );
+    },
 
-        audioSource.connect(compressor);
-        compressor.connect(audioContext.destination);
-      },
-      { once: true, passive: true },
-    );
+    stop() {
+      document.removeEventListener('ytmd:audio-can-play', audioCanPlayHandler);
+      storage.disconnectCompressor();
+    },
   },
 });