Fix filtering of "mp4a.40.34" variants in Safari

src/controller/level-controller.ts

@@ -16,6 +16,7 @@
   codecsSetSelectionPreferenceValue,
   convertAVC1ToAVCOTI,
   getCodecCompatibleName,
+  getM2TSSupportedAudioTypes,
   videoCodecPreferenceValue,
 } from '../utils/codecs';
 import BasePlaylistController from './base-playlist-controller';
@@ -27,8 +28,6 @@
 import type { HlsUrlParameters, LevelParsed } from '../types/level';
 import type { MediaPlaylist } from '../types/media-playlist';
 
-let chromeOrFirefox: boolean;
-
 export default class LevelController extends BasePlaylistController {
   private _levels: Level[] = [];
   private _firstLevel: number = -1;
@@ -119,22 +118,12 @@
 
     data.levels.forEach((levelParsed: LevelParsed) => {
       const attributes = levelParsed.attrs;
-
-      // erase audio codec info if browser does not support mp4a.40.34.
-      // demuxer will autodetect codec and fallback to mpeg/audio
       let { audioCodec, videoCodec } = levelParsed;
-      if (audioCodec?.indexOf('mp4a.40.34') !== -1) {
-        chromeOrFirefox ||= /chrome|firefox/i.test(navigator.userAgent);
-        if (chromeOrFirefox) {
-          levelParsed.audioCodec = audioCodec = undefined;
-        }
-      }
-
       if (audioCodec) {
-        levelParsed.audioCodec = audioCodec = getCodecCompatibleName(
-          audioCodec,
-          preferManagedMediaSource,
-        );
+        // Returns empty and set to undefined for 'mp4a.40.34' with fallback to 'audio/mpeg' SourceBuffer
+        levelParsed.audioCodec = audioCodec =
+          getCodecCompatibleName(audioCodec, preferManagedMediaSource) ||
+          undefined;
       }
 
       if (videoCodec?.indexOf('avc1') === 0) {

src/demux/transmuxer-interface.ts

@@ -12,14 +12,13 @@ import Transmuxer, {
 } from '../demux/transmuxer';
 import { logger } from '../utils/logger';
 import { ErrorTypes, ErrorDetails } from '../errors';
-import { getMediaSource } from '../utils/mediasource-helper';
 import { EventEmitter } from 'eventemitter3';
 import { Fragment, Part } from '../loader/fragment';
+import { getM2TSSupportedAudioTypes } from '../utils/codecs';
 import type { ChunkMetadata, TransmuxerResult } from '../types/transmuxer';
 import type Hls from '../hls';
 import type { HlsEventEmitter } from '../events';
 import type { PlaylistLevelType } from '../types/loader';
-import type { TypeSupported } from './tsdemuxer';
 import type { RationalTimestamp } from '../utils/timescale-conversion';
 
 export default class TransmuxerInterface {
@@ -64,16 +63,9 @@ export default class TransmuxerInterface {
     this.observer.on(Events.FRAG_DECRYPTED, forwardMessage);
     this.observer.on(Events.ERROR, forwardMessage);
 
-    const MediaSource = getMediaSource(config.preferManagedMediaSource) || {
-      isTypeSupported: () => false,
-    };
-    const m2tsTypeSupported: TypeSupported = {
-      mpeg: MediaSource.isTypeSupported('audio/mpeg'),
-      mp3: MediaSource.isTypeSupported('audio/mp4; codecs="mp3"'),
-      ac3: __USE_M2TS_ADVANCED_CODECS__
-        ? MediaSource.isTypeSupported('audio/mp4; codecs="ac-3"')
-        : false,
-    };
+    const m2tsTypeSupported = getM2TSSupportedAudioTypes(
+      config.preferManagedMediaSource,
+    );
 
     // navigator.vendor is not always available in Web Worker
     // refer to https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope/navigator

src/demux/transmuxer.ts

@@ -4,7 +4,7 @@ import { ErrorTypes, ErrorDetails } from '../errors';
 import Decrypter from '../crypt/decrypter';
 import AACDemuxer from './audio/aacdemuxer';
 import MP4Demuxer from '../demux/mp4demuxer';
-import TSDemuxer, { TypeSupported } from '../demux/tsdemuxer';
+import TSDemuxer from '../demux/tsdemuxer';
 import MP3Demuxer from './audio/mp3demuxer';
 import { AC3Demuxer } from './audio/ac3-demuxer';
 import MP4Remuxer from '../remux/mp4-remuxer';
@@ -16,6 +16,7 @@ import type { TransmuxerResult, ChunkMetadata } from '../types/transmuxer';
 import type { HlsConfig } from '../config';
 import type { DecryptData } from '../loader/level-key';
 import type { PlaylistLevelType } from '../types/loader';
+import type { TypeSupported } from '../utils/codecs';
 import type { RationalTimestamp } from '../utils/timescale-conversion';
 import { optionalSelf } from '../utils/global';
 

src/demux/tsdemuxer.ts

@@ -20,20 +20,21 @@ import { logger } from '../utils/logger';
 import { ErrorTypes, ErrorDetails } from '../errors';
 import type { HlsConfig } from '../config';
 import type { HlsEventEmitter } from '../events';
+import type { TypeSupported } from '../utils/codecs';
 import {
-  DemuxedVideoTrack,
-  DemuxedAudioTrack,
-  DemuxedTrack,
-  Demuxer,
-  DemuxerResult,
-  VideoSample,
-  DemuxedMetadataTrack,
-  DemuxedUserdataTrack,
-  ElementaryStreamData,
-  KeyData,
   MetadataSchema,
+  type DemuxedVideoTrack,
+  type DemuxedAudioTrack,
+  type DemuxedTrack,
+  type Demuxer,
+  type DemuxerResult,
+  type VideoSample,
+  type DemuxedMetadataTrack,
+  type DemuxedUserdataTrack,
+  type ElementaryStreamData,
+  type KeyData,
 } from '../types/demuxer';
-import { AudioFrame } from '../types/demuxer';
+import type { AudioFrame } from '../types/demuxer';
 
 export type ParsedTimestamp = {
   pts?: number;
@@ -48,12 +49,6 @@ export type PES = ParsedTimestamp & {
 export type ParsedVideoSample = ParsedTimestamp &
   Omit<VideoSample, 'pts' | 'dts'>;
 
-export interface TypeSupported {
-  mpeg: boolean;
-  mp3: boolean;
-  ac3: boolean;
-}
-
 const PACKET_LENGTH = 188;
 
 class TSDemuxer implements Demuxer {

src/remux/mp4-remuxer.ts

@@ -29,6 +29,7 @@ import type { TrackSet } from '../types/track';
 import type { SourceBufferName } from '../types/buffer';
 import type { Fragment } from '../loader/fragment';
 import type { HlsConfig } from '../config';
+import type { TypeSupported } from '../utils/codecs';
 
 const MAX_SILENT_FRAME_DURATION = 10 * 1000; // 10 seconds
 const AAC_SAMPLES_PER_FRAME = 1024;
@@ -41,7 +42,7 @@ let safariWebkitVersion: number | null = null;
 export default class MP4Remuxer implements Remuxer {
   private observer: HlsEventEmitter;
   private config: HlsConfig;
-  private typeSupported: any;
+  private typeSupported: TypeSupported;
   private ISGenerated: boolean = false;
   private _initPTS: RationalTimestamp | null = null;
   private _initDTS: RationalTimestamp | null = null;

src/utils/codecs.ts

@@ -147,12 +147,15 @@ function getCodecCompatibleNameLower(
     return CODEC_COMPATIBLE_NAMES[lowerCaseCodec]!;
   }
 
-  // Idealy fLaC and Opus would be first (spec-compliant) but
-  // some browsers will report that fLaC is supported then fail.
-  // see: https://bugs.chromium.org/p/chromium/issues/detail?id=1422728
   const codecsToCheck = {
+    // Idealy fLaC and Opus would be first (spec-compliant) but
+    // some browsers will report that fLaC is supported then fail.
+    // see: https://bugs.chromium.org/p/chromium/issues/detail?id=1422728
     flac: ['flac', 'fLaC', 'FLAC'],
     opus: ['opus', 'Opus'],
+    // Replace audio codec info if browser does not support mp4a.40.34,
+    // and demuxer can fallback to 'audio/mpeg' or 'audio/mp4;codecs="mp3"'
+    'mp4a.40.34': ['mp3'],
   }[lowerCaseCodec];
 
   for (let i = 0; i < codecsToCheck.length; i++) {
@@ -165,13 +168,18 @@ function getCodecCompatibleNameLower(
     ) {
       CODEC_COMPATIBLE_NAMES[lowerCaseCodec] = codecsToCheck[i];
       return codecsToCheck[i];
+    } else if (
+      codecsToCheck[i] === 'mp3' &&
+      getMediaSource(preferManagedMediaSource)?.isTypeSupported('audio/mpeg')
+    ) {
+      return '';
     }
   }
 
   return lowerCaseCodec;
 }
 
-const AUDIO_CODEC_REGEXP = /flac|opus/i;
+const AUDIO_CODEC_REGEXP = /flac|opus|mp4a\.40\.34/i;
 export function getCodecCompatibleName(
   codec: string,
   preferManagedMediaSource = true,
@@ -209,3 +217,24 @@ export function convertAVC1ToAVCOTI(codec: string) {
   }
   return codec;
 }
+
+export interface TypeSupported {
+  mpeg: boolean;
+  mp3: boolean;
+  ac3: boolean;
+}
+
+export function getM2TSSupportedAudioTypes(
+  preferManagedMediaSource: boolean,
+): TypeSupported {
+  const MediaSource = getMediaSource(preferManagedMediaSource) || {
+    isTypeSupported: () => false,
+  };
+  return {
+    mpeg: MediaSource.isTypeSupported('audio/mpeg'),
+    mp3: MediaSource.isTypeSupported('audio/mp4; codecs="mp3"'),
+    ac3: __USE_M2TS_ADVANCED_CODECS__
+      ? MediaSource.isTypeSupported('audio/mp4; codecs="ac-3"')
+      : false,
+  };
+}