fix(HLS): getPlayheadTimeAsDate() differs from X-EXT-PROGRAM-DATE-TIME (

#6371) Fixes #5939
shaka-project · Apr 2, 2024 · c615cf4 · c615cf4
1 parent 7c6e846
commit c615cf4
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Showing 4 changed files with 65 additions and 2 deletions.
diff --git a/lib/hls/hls_parser.js b/lib/hls/hls_parser.js
@@ -1003,6 +1003,22 @@ shaka.hls.HlsParser = class {
         this.presentationTimeline_.setSegmentAvailabilityDuration(
             segmentAvailabilityDuration);
       }
+
+      if (!this.presentationTimeline_.isStartTimeLocked()) {
+        for (const streamInfo of this.uriToStreamInfosMap_.values()) {
+          if (!streamInfo.stream.segmentIndex) {
+            continue; // Not active.
+          }
+          if (streamInfo.type != 'audio' && streamInfo.type != 'video') {
+            continue;
+          }
+          const firstReference = streamInfo.stream.segmentIndex.get(0);
+          if (firstReference && firstReference.syncTime) {
+            const syncTime = firstReference.syncTime;
+            this.presentationTimeline_.setInitialProgramDateTime(syncTime);
+          }
+        }
+      }
     } else {
       // Use the minimum duration as the presentation duration.
       this.presentationTimeline_.setDuration(this.getMinDuration_());

diff --git a/lib/media/presentation_timeline.js b/lib/media/presentation_timeline.js
@@ -96,6 +96,9 @@ shaka.media.PresentationTimeline = class {
 
     /** @private {boolean} */
     this.startTimeLocked_ = false;
+
+    /** @private {?number} */
+    this.initialProgramDateTime_ = null;
   }
 
 
@@ -339,6 +342,37 @@ shaka.media.PresentationTimeline = class {
   }
 
 
+  /**
+   * Returns if the presentation timeline's start time is locked.
+   *
+   * @return {boolean}
+   * @export
+   */
+  isStartTimeLocked() {
+    return this.startTimeLocked_;
+  }
+
+
+  /**
+   * Sets the initial program date time.
+   *
+   * @param {number} initialProgramDateTime
+   * @export
+   */
+  setInitialProgramDateTime(initialProgramDateTime) {
+    this.initialProgramDateTime_ = initialProgramDateTime;
+  }
+
+
+  /**
+   * @return {?number} The initial program date time in seconds.
+   * @export
+   */
+  getInitialProgramDateTime() {
+    return this.initialProgramDateTime_;
+  }
+
+
   /**
    * Gives PresentationTimeline a Stream's minimum segment start time.
    *

diff --git a/lib/player.js b/lib/player.js
@@ -4665,7 +4665,8 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
 
     if (this.manifest_) {
       const timeline = this.manifest_.presentationTimeline;
-      const startTime = timeline.getPresentationStartTime();
+      const startTime = timeline.getInitialProgramDateTime() ||
+          timeline.getPresentationStartTime();
       return new Date(/* ms= */ (startTime + presentationTime) * 1000);
     } else if (this.video_ && this.video_.getStartDate) {
       // Apple's native HLS gives us getStartDate(), which is only available if

diff --git a/test/player_unit.js b/test/player_unit.js
@@ -3800,11 +3800,14 @@ describe('Player', () => {
   });
 
   describe('getPlayheadTimeAsDate()', () => {
+    /** @type {?shaka.media.PresentationTimeline} */
+    let timeline;
     beforeEach(async () => {
-      const timeline = new shaka.media.PresentationTimeline(300, 0);
+      timeline = new shaka.media.PresentationTimeline(300, 0);
       timeline.setStatic(false);
 
       manifest = shaka.test.ManifestGenerator.generate((manifest) => {
+        goog.asserts.assert(timeline, 'timeline must be non-null');
         manifest.presentationTimeline = timeline;
         manifest.addVariant(0, (variant) => {
           variant.addVideo(1);
@@ -3822,6 +3825,15 @@ describe('Player', () => {
       // (300 (presentation start time) + 20 (playhead time)) * 1000 (ms/sec)
       expect(liveTimeUtc).toEqual(new Date(320 * 1000));
     });
+
+    it('uses program date time', () => {
+      timeline.setInitialProgramDateTime(100);
+      playhead.getTime.and.returnValue(20);
+
+      const liveTimeUtc = player.getPlayheadTimeAsDate();
+      // (100 (program date time) + 20 (playhead time)) * 1000 (ms/sec)
+      expect(liveTimeUtc).toEqual(new Date(120 * 1000));
+    });
   });
 
   describe('getSegmentAvailabilityDuration()', () => {