fix(hls): Fixed buffering issue with live HLS

lib/hls/hls_parser.js

@@ -1704,7 +1704,6 @@ shaka.hls.HlsParser = class {
    * @param {shaka.media.SegmentReference} previousReference
    * @param {!shaka.hls.Segment} hlsSegment
    * @param {number} startTime
-   * @param {number} timestampOffset
    * @param {!Map.<string, string>} variables
    * @param {string} absoluteMediaPlaylistUri
    * @return {!shaka.media.SegmentReference}
@@ -1713,7 +1712,7 @@ shaka.hls.HlsParser = class {
    */
   createSegmentReference_(
       initSegmentReference, previousReference, hlsSegment, startTime,
-      timestampOffset, variables, absoluteMediaPlaylistUri, type) {
+      variables, absoluteMediaPlaylistUri, type) {
     const tags = hlsSegment.tags;
     const absoluteSegmentUri = this.variableSubstitution_(
         hlsSegment.absoluteUri, variables);
@@ -1766,7 +1765,7 @@ shaka.hls.HlsParser = class {
             pStartByte,
             pEndByte,
             initSegmentReference,
-            timestampOffset,
+            /* timestampOffset= */ 0, // This value is ignored in sequence mode.
             /* appendWindowStart= */ 0,
             /* appendWindowEnd= */ Infinity);
         partialSegmentRefs.push(partial);
@@ -1834,7 +1833,7 @@ shaka.hls.HlsParser = class {
         startByte,
         endByte,
         initSegmentReference,
-        timestampOffset,
+        /* timestampOffset= */ 0, // This value is ignored in sequence mode.
         /* appendWindowStart= */ 0,
         /* appendWindowEnd= */ Infinity,
         partialSegmentRefs,
@@ -1960,7 +1959,6 @@ shaka.hls.HlsParser = class {
           previousReference,
           item,
           startTime,
-          firstStartTime,
           variables,
           playlist.absoluteUri,
           type);

lib/media/media_source_engine.js

@@ -691,13 +691,18 @@ shaka.media.MediaSourceEngine = class {
    * @param {number} appendWindowEnd The timestamp to set the append window end
    *   to.  For future appends, frames/samples with timestamps greater than this
    *   value will be dropped.
+   * @param {boolean} sequenceMode  If true, the timestampOffset will not be
+   *   applied in this step.
    * @return {!Promise}
    */
   async setStreamProperties(
-      contentType, timestampOffset, appendWindowStart, appendWindowEnd) {
+      contentType, timestampOffset, appendWindowStart, appendWindowEnd,
+      sequenceMode) {
     const ContentType = shaka.util.ManifestParserUtils.ContentType;
     if (contentType == ContentType.TEXT) {
-      this.textEngine_.setTimestampOffset(timestampOffset);
+      if (!sequenceMode) {
+        this.textEngine_.setTimestampOffset(timestampOffset);
+      }
       this.textEngine_.setAppendWindow(appendWindowStart, appendWindowEnd);
       return;
     }
@@ -714,7 +719,10 @@ shaka.media.MediaSourceEngine = class {
       this.enqueueOperation_(
           contentType,
           () => this.abort_(contentType)),
-      this.enqueueOperation_(
+      // Don't set the timestampOffset here when in sequenceMode, since we
+      // use timestampOffset for a different purpose in that mode (e.g. to
+      // indicate where the current segment is).
+      sequenceMode ? Promise.resolve() : this.enqueueOperation_(
           contentType,
           () => this.setTimestampOffset_(contentType, timestampOffset)),
       this.enqueueOperation_(

lib/media/streaming_engine.js

@@ -1520,7 +1520,7 @@ shaka.media.StreamingEngine = class {
 
           await this.playerInterface_.mediaSourceEngine.setStreamProperties(
               mediaState.type, timestampOffset, appendWindowStart,
-              appendWindowEnd);
+              appendWindowEnd, this.manifest_.sequenceMode);
         } catch (error) {
           mediaState.lastAppendWindowStart = null;
           mediaState.lastAppendWindowEnd = null;

test/media/media_source_engine_integration.js

@@ -295,7 +295,27 @@ describe('MediaSourceEngine', () => {
     await mediaSourceEngine.setStreamProperties(ContentType.VIDEO,
         /* timestampOffset= */ 0,
         /* appendWindowStart= */ 5,
-        /* appendWindowEnd= */ 18);
+        /* appendWindowEnd= */ 18,
+        /* sequenceMode= */ false);
+    expect(buffered(ContentType.VIDEO, 0)).toBe(0);
+    await append(ContentType.VIDEO, 0);
+    expect(bufferStart(ContentType.VIDEO)).toBeCloseTo(5, 1);
+    expect(buffered(ContentType.VIDEO, 5)).toBeCloseTo(5, 1);
+    await append(ContentType.VIDEO, 1);
+    expect(buffered(ContentType.VIDEO, 5)).toBeCloseTo(13, 1);
+  });
+
+  it('does not initialize timestamp offset in sequence mode', async () => {
+    const initObject = new Map();
+    initObject.set(ContentType.VIDEO, getFakeStream(metadata.video));
+    await mediaSourceEngine.init(initObject, false);
+    await mediaSourceEngine.setDuration(presentationDuration);
+    await appendInit(ContentType.VIDEO);
+    await mediaSourceEngine.setStreamProperties(ContentType.VIDEO,
+        /* timestampOffset= */ 100,
+        /* appendWindowStart= */ 5,
+        /* appendWindowEnd= */ 18,
+        /* sequenceMode= */ true);
     expect(buffered(ContentType.VIDEO, 0)).toBe(0);
     await append(ContentType.VIDEO, 0);
     expect(bufferStart(ContentType.VIDEO)).toBeCloseTo(5, 1);
@@ -314,7 +334,8 @@ describe('MediaSourceEngine', () => {
     await mediaSourceEngine.setStreamProperties(ContentType.VIDEO,
         /* timestampOffset= */ 0,
         /* appendWindowStart= */ 0,
-        /* appendWindowEnd= */ 20);
+        /* appendWindowEnd= */ 20,
+        /* sequenceMode= */ false);
     await append(ContentType.VIDEO, 0);
     await append(ContentType.VIDEO, 1);
     expect(bufferStart(ContentType.VIDEO)).toBeCloseTo(0, 1);
@@ -326,7 +347,8 @@ describe('MediaSourceEngine', () => {
     await mediaSourceEngine.setStreamProperties(ContentType.VIDEO,
         /* timestampOffset= */ 15,
         /* appendWindowStart= */ 20,
-        /* appendWindowEnd= */ 35);
+        /* appendWindowEnd= */ 35,
+        /* sequenceMode= */ false);
     await append(ContentType.VIDEO, 0);
     await append(ContentType.VIDEO, 1);
     expect(bufferStart(ContentType.VIDEO)).toBeCloseTo(0, 1);

test/media/media_source_engine_unit.js

@@ -825,7 +825,8 @@ describe('MediaSourceEngine', () => {
       await mediaSourceEngine.setStreamProperties(ContentType.TEXT,
           /* timestampOffset= */ 10,
           /* appendWindowStart= */ 0,
-          /* appendWindowEnd= */ 20);
+          /* appendWindowEnd= */ 20,
+          /* sequenceMode= */ false);
       expect(mockTextEngine.setTimestampOffset).toHaveBeenCalledWith(10);
       expect(mockTextEngine.setAppendWindow).toHaveBeenCalledWith(0, 20);
     });

test/media/streaming_engine_unit.js

@@ -826,7 +826,7 @@ describe('StreamingEngine', () => {
       asymmetricMatch: (val) => val > 40 && val <= 40.1,
     };
     expect(mediaSourceEngine.setStreamProperties)
-        .toHaveBeenCalledWith('video', 0, lt20, gt40);
+        .toHaveBeenCalledWith('video', 0, lt20, gt40, false);
   });
 
   // Regression test for https://github.com/google/shaka-player/issues/3717

test/test/util/fake_media_source_engine.js

@@ -114,8 +114,8 @@ shaka.test.FakeMediaSourceEngine = class {
 
     /** @type {!jasmine.Spy} */
     this.setStreamProperties = jasmine.createSpy('setStreamProperties')
-        .and.callFake((type, offset, end) =>
-          this.setStreamPropertiesImpl_(type, offset, end));
+        .and.callFake((type, offset, end, sequenceMode) =>
+          this.setStreamPropertiesImpl_(type, offset, end, sequenceMode));
 
     /** @type {!jasmine.Spy} */
     this.remove = jasmine.createSpy('remove')
@@ -362,14 +362,17 @@ shaka.test.FakeMediaSourceEngine = class {
    * @param {string} type
    * @param {number} offset
    * @param {number} appendWindowEnd
+   * @param {boolean} sequenceMode
    * @return {!Promise}
    * @private
    */
-  setStreamPropertiesImpl_(type, offset, appendWindowEnd) {
+  setStreamPropertiesImpl_(type, offset, appendWindowEnd, sequenceMode) {
     if (!this.segments[type]) {
       throw new Error('unexpected type');
     }
-    this.timestampOffsets_[type] = offset;
+    if (!sequenceMode) {
+      this.timestampOffsets_[type] = offset;
+    }
     // Don't use |appendWindowEnd|.
     return Promise.resolve();
   }