fix: CMAF HLS. Source buffer change type is called with wrong codecs sometimes when append segment without init data because of a race condition. (#1374)

* Get Codecs: Always use playlist for current pending segment instead of currently loaded playlist.

* fix eslint errors

* Clear active init segment id during reset everything

---------

Co-authored-by: Dzianis Dashkevich <ddashkevich@brightcove.com>

Author: dzianis-dashkevich

src/master-playlist-controller.js

@@ -1725,9 +1725,11 @@ export class MasterPlaylistController extends videojs.EventTarget {
       audio: this.audioSegmentLoader_.getCurrentMediaInfo_() || {}
     };
 
+    const playlist = this.mainSegmentLoader_.getPendingSegmentPlaylist() || this.media();
+
     // set "main" media equal to video
     media.video = media.main;
-    const playlistCodecs = codecsForPlaylist(this.master(), this.media());
+    const playlistCodecs = codecsForPlaylist(this.master(), playlist);
     const codecs = {};
     const usingAudioLoader = !!this.mediaTypes_.AUDIO.activePlaylistLoader;
 
@@ -1748,7 +1750,7 @@ export class MasterPlaylistController extends videojs.EventTarget {
     // no codecs, no playback.
     if (!codecs.audio && !codecs.video) {
       this.blacklistCurrentPlaylist({
-        playlist: this.media(),
+        playlist,
         message: 'Could not determine codecs for playlist.',
         blacklistDuration: Infinity
       });
@@ -1773,13 +1775,13 @@ export class MasterPlaylistController extends videojs.EventTarget {
       }
     });
 
-    if (usingAudioLoader && unsupportedAudio && this.media().attributes.AUDIO) {
-      const audioGroup = this.media().attributes.AUDIO;
+    if (usingAudioLoader && unsupportedAudio && playlist.attributes.AUDIO) {
+      const audioGroup = playlist.attributes.AUDIO;
 
       this.master().playlists.forEach(variant => {
         const variantAudioGroup = variant.attributes && variant.attributes.AUDIO;
 
-        if (variantAudioGroup === audioGroup && variant !== this.media()) {
+        if (variantAudioGroup === audioGroup && variant !== playlist) {
           variant.excludeUntil = Infinity;
         }
       });
@@ -1800,7 +1802,7 @@ export class MasterPlaylistController extends videojs.EventTarget {
       }, '') + '.';
 
       this.blacklistCurrentPlaylist({
-        playlist: this.media(),
+        playlist,
         internal: true,
         message,
         blacklistDuration: Infinity
@@ -1825,7 +1827,7 @@ export class MasterPlaylistController extends videojs.EventTarget {
 
       if (switchMessages.length) {
         this.blacklistCurrentPlaylist({
-          playlist: this.media(),
+          playlist,
           message: `Codec switching not supported: ${switchMessages.join(', ')}.`,
           blacklistDuration: Infinity,
           internal: true

src/segment-loader.js

@@ -1162,6 +1162,7 @@ export default class SegmentLoader extends videojs.EventTarget {
    */
   resetEverything(done) {
     this.ended_ = false;
+    this.activeInitSegmentId_ = null;
     this.appendInitSegment_ = {
       audio: true,
       video: true
@@ -1982,6 +1983,10 @@ export default class SegmentLoader extends videojs.EventTarget {
     return this.getCurrentMediaInfo_(segmentInfo) || this.startingMediaInfo_;
   }
 
+  getPendingSegmentPlaylist() {
+    return this.pendingSegment_ ? this.pendingSegment_.playlist : null;
+  }
+
   hasEnoughInfoToAppend_() {
     if (!this.sourceUpdater_.ready()) {
       return false;

test/master-playlist-controller.test.js

@@ -5092,6 +5092,25 @@ QUnit.test('playlist codecs take priority over others', function(assert) {
   assert.deepEqual(codecs, {video: 'avc1.4b400d', audio: 'mp4a.40.20'}, 'codecs returned');
 });
 
+QUnit.test('Current pending segment\'s playlist codecs take priority over others', function(assert) {
+  this.contentSetup({
+    mainStartingMedia: {videoCodec: 'avc1.4c400d', hasVideo: true, hasAudio: false},
+    audioStartingMedia: {audioCodec: 'mp4a.40.5', hasVideo: false, hasAudio: true},
+    mainPlaylist: {attributes: {CODECS: 'avc1.4b400d', AUDIO: 'low-quality'}},
+    audioPlaylist: {attributes: {CODECS: 'mp4a.40.20'}}
+  });
+
+  const originalGetPendingSegmentPlaylist = this.mpc.mainSegmentLoader_.getPendingSegmentPlaylist.bind(this.mpc.mainSegmentLoader_);
+
+  this.mpc.mainSegmentLoader_.getPendingSegmentPlaylist = () => ({attributes: {CODECS: 'avc1.64001f', AUDIO: 'low-quality'}});
+
+  const codecs = this.mpc.getCodecsOrExclude_();
+
+  assert.deepEqual(this.blacklists, [], 'did not blacklist anything');
+  assert.deepEqual(codecs, {video: 'avc1.64001f', audio: 'mp4a.40.20'}, 'codecs returned');
+  this.mpc.mainSegmentLoader_.getPendingSegmentPlaylist = originalGetPendingSegmentPlaylist;
+});
+
 QUnit.test('uses default codecs if no codecs are found', function(assert) {
   this.contentSetup({
     mainStartingMedia: {hasVideo: true, hasAudio: false},
@@ -5123,6 +5142,27 @@ QUnit.test('excludes playlist without detected audio/video', function(assert) {
   assert.deepEqual(codecs, void 0, 'no codecs returned');
 });
 
+QUnit.test('excludes current pending segment\'s playlist without detected audio/video', function(assert) {
+  this.contentSetup({
+    mainStartingMedia: {},
+    audioStartingMedia: {},
+    mainPlaylist: {attributes: {}}
+  });
+
+  const originalGetPendingSegmentPlaylist = this.mpc.mainSegmentLoader_.getPendingSegmentPlaylist.bind(this.mpc.mainSegmentLoader_);
+
+  this.mpc.mainSegmentLoader_.getPendingSegmentPlaylist = () => ({attributes: {CODECS: ''}});
+  const codecs = this.mpc.getCodecsOrExclude_();
+
+  assert.deepEqual(this.blacklists, [{
+    blacklistDuration: Infinity,
+    message: 'Could not determine codecs for playlist.',
+    playlist: {attributes: {CODECS: ''}}
+  }], 'blacklisted playlist');
+  assert.deepEqual(codecs, void 0, 'no codecs returned');
+  this.mpc.mainSegmentLoader_.getPendingSegmentPlaylist = originalGetPendingSegmentPlaylist;
+});
+
 QUnit.test('excludes unsupported muxer codecs for ts', function(assert) {
   this.contentSetup({
     mainStartingMedia: {