From d2507a5a72c70dfd7cd36fe83beb76648633cec0 Mon Sep 17 00:00:00 2001
From: Vanilagy <1696106+Vanilagy@users.noreply.github.com>
Date: Mon, 1 Sep 2025 16:39:19 +0200
Subject: [PATCH] Fix incorrect decoded audio sample timestamps in Firefox

---
 package-lock.json                 | 12 ++++++------
 package.json                      |  2 +-
 packages/mp3-encoder/package.json |  2 +-
 src/media-sink.ts                 | 19 +++++++++++++++++--
 4 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index dbc4aae..bd1b3e0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "mediabunny",
-  "version": "1.12.0",
+  "version": "1.12.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mediabunny",
-      "version": "1.12.0",
+      "version": "1.12.1",
       "license": "MPL-2.0",
       "workspaces": [
         "packages/*"
@@ -6147,9 +6147,9 @@
       }
     },
     "node_modules/mediabunny": {
-      "version": "1.11.2",
-      "resolved": "https://registry.npmjs.org/mediabunny/-/mediabunny-1.11.2.tgz",
-      "integrity": "sha512-dZpaq+YMKo5dUz6HlwWtZJfKPf3rZCq9BXurC7/zVmgjB3sTW5l32VT65gWm/ojv0vUwH+WbtolkmOQX1viz5g==",
+      "version": "1.12.0",
+      "resolved": "https://registry.npmjs.org/mediabunny/-/mediabunny-1.12.0.tgz",
+      "integrity": "sha512-BARnydaYDY9iCar+ZRdnaKER31c2J4otsEVcSRsizXRrFLv97LXSd5ilD5FQF52AaM6FiqLm7iB3Zl1C+a5u9w==",
       "license": "MPL-2.0",
       "peer": true,
       "workspaces": [
@@ -9478,7 +9478,7 @@
     },
     "packages/mp3-encoder": {
       "name": "@mediabunny/mp3-encoder",
-      "version": "1.12.0",
+      "version": "1.12.1",
       "license": "MPL-2.0",
       "devDependencies": {
         "@types/emscripten": "^1.40.1"
diff --git a/package.json b/package.json
index 7b443cd..8e85294 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "mediabunny",
   "author": "Vanilagy",
-  "version": "1.12.0",
+  "version": "1.12.1",
   "description": "Pure TypeScript media toolkit for reading, writing, and converting media files, directly in the browser.",
   "type": "module",
   "workspaces": [
diff --git a/packages/mp3-encoder/package.json b/packages/mp3-encoder/package.json
index b860afd..f1be561 100644
--- a/packages/mp3-encoder/package.json
+++ b/packages/mp3-encoder/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@mediabunny/mp3-encoder",
   "author": "Vanilagy",
-  "version": "1.12.0",
+  "version": "1.12.1",
   "description": "MP3 encoder extension for Mediabunny, based on LAME.",
   "main": "./dist/bundles/mediabunny-mp3-encoder.mjs",
   "module": "./dist/bundles/mediabunny-mp3-encoder.mjs",
diff --git a/src/media-sink.ts b/src/media-sink.ts
index 6506f4f..b419e46 100644
--- a/src/media-sink.ts
+++ b/src/media-sink.ts
@@ -1217,6 +1217,10 @@ class AudioDecoderWrapper extends DecoderWrapper<AudioSample> {
 	customDecoderCallSerializer = new CallSerializer();
 	customDecoderQueueSize = 0;
 
+	// Internal state to accumulate a precise current timestamp based on audio durations, not the (potentially
+	// inaccurate) packet timestamps.
+	currentTimestamp: number | null = null;
+
 	constructor(
 		onSample: (sample: AudioSample) => unknown,
 		onError: (error: DOMException) => unknown,
@@ -1226,6 +1230,17 @@ class AudioDecoderWrapper extends DecoderWrapper<AudioSample> {
 		super(onSample, onError);
 
 		const sampleHandler = (sample: AudioSample) => {
+			if (
+				this.currentTimestamp === null
+				|| Math.abs(sample.timestamp - this.currentTimestamp) >= sample.duration
+			) {
+				// We need to sync with the sample timestamp again
+				this.currentTimestamp = sample.timestamp;
+			}
+
+			const preciseTimestamp = this.currentTimestamp;
+			this.currentTimestamp += sample.duration;
+
 			if (sample.numberOfFrames === 0) {
 				// We skip zero-data (empty) AudioSamples. These are sometimes emitted, for example, by Firefox when it
 				// decodes Vorbis (at the start).
@@ -1235,7 +1250,7 @@ class AudioDecoderWrapper extends DecoderWrapper<AudioSample> {
 
 			// Round the timestamp to the sample rate
 			const sampleRate = decoderConfig.sampleRate;
-			sample.setTimestamp(Math.round(sample.timestamp * sampleRate) / sampleRate);
+			sample.setTimestamp(Math.round(preciseTimestamp * sampleRate) / sampleRate);
 
 			onSample(sample);
 		};
@@ -1320,7 +1335,7 @@ class PcmAudioDecoderWrapper extends DecoderWrapper<AudioSample> {
 	writeOutputValue: (view: DataView, byteOffset: number, value: number) => void;
 
 	// Internal state to accumulate a precise current timestamp based on audio durations, not the (potentially
-	// inaccurate) sample timestamps.
+	// inaccurate) packet timestamps.
 	currentTimestamp: number | null = null;
 
 	constructor(