base audio demuxer: track PTS of last sample for ID3 frames (#5014)

video-dev · Nov 12, 2022 · a93c41a · a93c41a
1 parent 2a607ff
commit a93c41a
Showing 1 changed file with 12 additions and 8 deletions.
diff --git a/src/demux/base-audio-demuxer.ts b/src/demux/base-audio-demuxer.ts
@@ -21,6 +21,7 @@ class BaseAudioDemuxer implements Demuxer {
   protected cachedData: Uint8Array | null = null;
   protected basePTS: number | null = null;
   protected initPTS: number | null = null;
+  protected lastPTS: number | null = null;
 
   resetInitSegment(
     initSegment: Uint8Array | undefined,
@@ -46,6 +47,7 @@ class BaseAudioDemuxer implements Demuxer {
 
   resetContiguity(): void {
     this.basePTS = null;
+    this.lastPTS = null;
     this.frameIndex = 0;
   }
 
@@ -69,7 +71,6 @@ class BaseAudioDemuxer implements Demuxer {
     let id3Data: Uint8Array | undefined = ID3.getID3Data(data, 0);
     let offset = id3Data ? id3Data.length : 0;
     let lastDataIndex;
-    let pts;
     const track = this._audioTrack;
     const id3Track = this._id3Track;
     const timestamp = id3Data ? ID3.getTimeStamp(id3Data) : undefined;
@@ -80,27 +81,30 @@ class BaseAudioDemuxer implements Demuxer {
       (this.frameIndex === 0 && Number.isFinite(timestamp))
     ) {
       this.basePTS = initPTSFn(timestamp, timeOffset, this.initPTS);
+      this.lastPTS = this.basePTS;
+    }
+
+    if (this.lastPTS === null) {
+      this.lastPTS = this.basePTS;
     }
 
     // more expressive than alternative: id3Data?.length
     if (id3Data && id3Data.length > 0) {
       id3Track.samples.push({
-        pts: this.basePTS,
-        dts: this.basePTS,
+        pts: this.lastPTS,
+        dts: this.lastPTS,
         data: id3Data,
         type: MetadataSchema.audioId3,
         duration: Number.POSITIVE_INFINITY,
       });
     }
 
-    pts = this.basePTS;
-
     while (offset < length) {
       if (this.canParse(data, offset)) {
         const frame = this.appendFrame(track, data, offset);
         if (frame) {
           this.frameIndex++;
-          pts = frame.sample.pts;
+          this.lastPTS = frame.sample.pts;
           offset += frame.length;
           lastDataIndex = offset;
         } else {
@@ -110,8 +114,8 @@ class BaseAudioDemuxer implements Demuxer {
         // after a ID3.canParse, a call to ID3.getID3Data *should* always returns some data
         id3Data = ID3.getID3Data(data, offset)!;
         id3Track.samples.push({
-          pts: pts,
-          dts: pts,
+          pts: this.lastPTS,
+          dts: this.lastPTS,
           data: id3Data,
           type: MetadataSchema.audioId3,
           duration: Number.POSITIVE_INFINITY,