fix: Allow use Chapter API on browsers without track element support (#8515)

Co-authored-by: Wojciech Tyczyński <[email protected]>

Author: avelad

lib/cast/cast_proxy.js

@@ -731,16 +731,6 @@ shaka.cast.CastProxy = class extends shaka.util.FakeEventTarget {
       return () => this.localPlayer_.getAdManager();
     }
 
-    if (name == 'getChapters') {
-      // This does not follow our standard pattern (takes an arguments), and
-      // therefore can't be proactively proxied and cached the way other
-      // synchronous getters can.
-      if (this.sender_.isCasting()) {
-        shaka.log.warning('NOTE: getChapters() does not work while casting!');
-      }
-      return () => [];
-    }
-
     if (name == 'setVideoContainer') {
       // Always returns a local instance.
       if (this.sender_.isCasting()) {
@@ -764,6 +754,16 @@ shaka.cast.CastProxy = class extends shaka.util.FakeEventTarget {
           return Promise.resolve();
         };
       }
+
+      if (name == 'getChapters') {
+        // This does not follow our standard pattern (takes an arguments), and
+        // therefore can't be proactively proxied and cached the way other
+        // synchronous getters can.
+        return () => {
+          shaka.log.alwaysWarn(name + '() does not work while casting!');
+          return [];
+        };
+      }
     }  // if (this.sender_.isCasting())
 
     // If we are casting, but the first update has not come in yet, use local

lib/player.js

@@ -823,6 +823,9 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
     /** @private {!Array<shaka.extern.Stream>} */
     this.externalSrcEqualsThumbnailsStreams_ = [];
 
+    /** @private {!Array<shaka.extern.Stream>} */
+    this.externalChaptersStreams_ = [];
+
     /** @private {number} */
     this.completionPercent_ = -1;
 
@@ -1591,6 +1594,7 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
       this.rebufferingCount_ = -1;
 
       this.externalSrcEqualsThumbnailsStreams_ = [];
+      this.externalChaptersStreams_ = [];
 
       this.completionPercent_ = -1;
 
@@ -6213,13 +6217,8 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
    * @export
    */
   getChaptersTracks() {
-    if (this.video_ && this.video_.currentSrc && this.video_.textTracks) {
-      const textTracks = this.getChaptersTracks_();
-      const StreamUtils = shaka.util.StreamUtils;
-      return textTracks.map((text) => StreamUtils.html5TextTrackToTrack(text));
-    } else {
-      return [];
-    }
+    return this.externalChaptersStreams_.map(
+        (text) => shaka.util.StreamUtils.textStreamToTrack(text));
   }
 
   /**
@@ -6230,38 +6229,35 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
    * @export
    */
   getChapters(language) {
-    if (!this.video_ || !this.video_.currentSrc || !this.video_.textTracks) {
+    if (!this.externalChaptersStreams_.length) {
       return [];
     }
     const LanguageUtils = shaka.util.LanguageUtils;
     const inputLanguage = LanguageUtils.normalize(language);
-    const chaptersTracks = this.getChaptersTracks_();
-    const chaptersTracksWithLanguage = chaptersTracks
-        .filter((t) => LanguageUtils.normalize(t.language) == inputLanguage);
-    if (!chaptersTracksWithLanguage || !chaptersTracksWithLanguage.length) {
+    const chapterStreams = this.externalChaptersStreams_
+        .filter((c) => LanguageUtils.normalize(c.language) == inputLanguage);
+    if (!chapterStreams.length) {
       return [];
     }
     const chapters = [];
     const uniqueChapters = new Set();
-    for (const chaptersTrack of chaptersTracksWithLanguage) {
-      if (chaptersTrack && chaptersTrack.cues) {
-        for (const cue of chaptersTrack.cues) {
-          let id = cue.id;
-          if (!id || id == '') {
-            id = cue.startTime + '-' + cue.endTime + '-' + cue.text;
-          }
+    for (const chapterStream of chapterStreams) {
+      if (chapterStream.segmentIndex) {
+        chapterStream.segmentIndex.forEachTopLevelReference((ref) => {
+          const title = ref.getUris()[0];
+          const id = ref.startTime + '-' + ref.endTime + '-' + title;
           /** @type {shaka.extern.Chapter} */
           const chapter = {
-            id: id,
-            title: cue.text,
-            startTime: cue.startTime,
-            endTime: cue.endTime,
+            id,
+            title,
+            startTime: ref.startTime,
+            endTime: ref.endTime,
           };
           if (!uniqueChapters.has(id)) {
             chapters.push(chapter);
             uniqueChapters.add(id);
           }
-        }
+        });
       }
     }
     return chapters;
@@ -6308,19 +6304,6 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
         .filter((t) => t.kind == 'metadata');
   }
 
-  /**
-   * Get the TextTracks with the 'chapters' kind.
-   *
-   * @return {!Array<TextTrack>}
-   * @private
-   */
-  getChaptersTracks_() {
-    goog.asserts.assert(this.video_.textTracks,
-        'TextTracks should be valid.');
-    return Array.from(this.video_.textTracks)
-        .filter((t) => t.kind == 'chapters');
-  }
-
   /**
    * Enable or disable the text displayer.  If the player is in an unloaded
    * state, the request will be applied next time content is loaded.
@@ -6985,47 +6968,100 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
       mimeType = await this.getTextMimetype_(uri);
     }
 
-    let adCuePoints = [];
-    if (this.adManager_) {
-      adCuePoints = this.adManager_.getCuePoints();
+    const ContentType = shaka.util.ManifestParserUtils.ContentType;
+    const seekRange = this.seekRange();
+    let duration = seekRange.end - seekRange.start;
+    if (this.manifest_) {
+      duration = this.manifest_.presentationTimeline.getDuration();
+    }
+    if (duration == Infinity) {
+      throw new shaka.util.Error(
+          shaka.util.Error.Severity.RECOVERABLE,
+          shaka.util.Error.Category.MANIFEST,
+          shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_CHAPTERS_TO_LIVE_STREAM);
     }
 
-    /** @type {!HTMLTrackElement} */
-    const trackElement = await this.addSrcTrackElement_(
-        uri, language, /* kind= */ 'chapters', mimeType, /* label= */ '',
-        adCuePoints);
+    goog.asserts.assert(
+        this.networkingEngine_, 'Need networking engine.');
+    const buffer = await this.getTextData_(uri,
+        this.networkingEngine_,
+        this.config_.streaming.retryParameters);
 
-    const chaptersTracks = this.getChaptersTracks();
-    const chaptersTrack = chaptersTracks.find((t) => {
-      return t.language == language;
-    });
+    const factory = shaka.text.TextEngine.findParser(mimeType);
+    if (!factory) {
+      throw new shaka.util.Error(
+          shaka.util.Error.Severity.CRITICAL,
+          shaka.util.Error.Category.TEXT,
+          shaka.util.Error.Code.MISSING_TEXT_PLUGIN,
+          mimeType);
+    }
+    const textParser = factory();
+    const time = {
+      periodStart: 0,
+      segmentStart: 0,
+      segmentEnd: duration,
+      vttOffset: 0,
+    };
+    const data = shaka.util.BufferUtils.toUint8(buffer);
+    const cues = textParser.parseMedia(data, time, uri, /* images= */ []);
 
-    if (chaptersTrack) {
-      await new Promise((resolve, reject) => {
-        // The chapter data isn't available until the 'load' event fires, and
-        // that won't happen until the chapters track is activated by the
-        // activateChaptersTrack_ method.
-        this.loadEventManager_.listenOnce(trackElement, 'load', resolve);
-        this.loadEventManager_.listenOnce(trackElement, 'error', (event) => {
-          reject(new shaka.util.Error(
-              shaka.util.Error.Severity.RECOVERABLE,
-              shaka.util.Error.Category.TEXT,
-              shaka.util.Error.Code.CHAPTERS_TRACK_FAILED));
-        });
-      });
+    const references = [];
+    for (const cue of cues) {
+      const reference = new shaka.media.SegmentReference(
+          cue.startTime,
+          cue.endTime,
+          () => [cue.payload],
+          /* startByte= */ 0,
+          /* endByte= */ null,
+          /* initSegmentReference= */ null,
+          /* timestampOffset= */ 0,
+          /* appendWindowStart= */ 0,
+          /* appendWindowEnd= */ Infinity,
+      );
+      references.push(reference);
+    }
 
-      this.onTracksChanged_();
+    const chaptersMimeType = 'text/plain';
 
-      return chaptersTrack;
-    }
+    /** @type {shaka.extern.Stream} */
+    const stream = {
+      id: this.nextExternalStreamId_++,
+      originalId: null,
+      groupId: null,
+      createSegmentIndex: () => Promise.resolve(),
+      segmentIndex: new shaka.media.SegmentIndex(references),
+      mimeType: chaptersMimeType,
+      codecs: '',
+      kind: '',
+      encrypted: false,
+      drmInfos: [],
+      keyIds: new Set(),
+      language: language,
+      originalLanguage: language,
+      label: null,
+      type: ContentType.TEXT,
+      primary: false,
+      trickModeVideo: null,
+      dependencyStream: null,
+      emsgSchemeIdUris: null,
+      roles: [],
+      forced: false,
+      channelsCount: null,
+      audioSamplingRate: null,
+      spatialAudio: false,
+      closedCaptions: null,
+      accessibilityPurpose: null,
+      external: true,
+      fastSwitching: false,
+      fullMimeTypes: new Set([shaka.util.MimeUtils.getFullType(
+          chaptersMimeType, '')]),
+      isAudioMuxedInVideo: false,
+      baseOriginalId: null,
+    };
 
-    // This should not happen, but there are browser implementations that may
-    // not support the Track element.
-    shaka.log.error('Cannot add this text when loaded with src=');
-    throw new shaka.util.Error(
-        shaka.util.Error.Severity.RECOVERABLE,
-        shaka.util.Error.Category.TEXT,
-        shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_TEXT_TO_SRC_EQUALS);
+    this.externalChaptersStreams_.push(stream);
+    this.onTracksChanged_();
+    return shaka.util.StreamUtils.textStreamToTrack(stream);
   }
 
   /**

lib/util/error.js

@@ -355,12 +355,7 @@ shaka.util.Error.Code = {
    */
   'MISSING_TEXT_PLUGIN': 2014,
 
-  /**
-   * The chapters track failed to load.  The browser does not provide any
-   * information in this case to identify why it failed, but there may be
-   * details in the JavaScript console.
-   */
-  'CHAPTERS_TRACK_FAILED': 2015,
+  // RETIRED: 'CHAPTERS_TRACK_FAILED': 2015,
 
   // RETIRED: 'CANNOT_ADD_EXTERNAL_THUMBNAILS_TO_SRC_EQUALS': 2016,
 
@@ -797,6 +792,11 @@ shaka.util.Error.Code = {
    */
   'DASH_MSE_ENCRYPTED_LEGACY_APPLE_MEDIA_KEYS_NOT_SUPPORTED': 4054,
 
+  /**
+   * External chapters cannot be added to live streams.
+   */
+  'CANNOT_ADD_EXTERNAL_CHAPTERS_TO_LIVE_STREAM': 4054,
+
   // RETIRED: 'INCONSISTENT_BUFFER_STATE': 5000,
   // RETIRED: 'INVALID_SEGMENT_INDEX': 5001,
   // RETIRED: 'SEGMENT_DOES_NOT_EXIST': 5002,