Texttrack cue start and end times are now based on ID3 tag pts values

zhoudaqing · May 26, 2017 · 4fb5fe9 · 4fb5fe9
1 parent d5aeda4
commit 4fb5fe9
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Showing 2 changed files with 11 additions and 10 deletions.
diff --git a/src/controller/id3-track-controller.js b/src/controller/id3-track-controller.js
@@ -39,12 +39,6 @@ class ID3TrackController extends EventHandler {
   onFragParsingMetadata(data) {
     const fragment = data.frag;
     const samples = data.samples;
-    const startTime = fragment.start;
-    let endTime = fragment.start + fragment.duration;
-    // Give a slight bump to the endTime if it's equal to startTime to avoid a SyntaxError in IE
-    if (startTime === endTime) {
-      endTime += 0.0001;
-    }
 
     // Attempt to recreate Safari functionality by creating
     // WebKitDataCue objects when available and store the decoded
@@ -54,10 +48,17 @@ class ID3TrackController extends EventHandler {
     for (let i = 0; i < samples.length; i++) {
       const frames = ID3.getID3Frames(samples[i].data);
       if (frames) {
+        const startTime = samples[i].pts;
+        let endTime = i < samples.length - 1 ? samples[i+1].pts : fragment.endPTS;
+
+        // Give a slight bump to the endTime if it's equal to startTime to avoid a SyntaxError in IE
+        if (startTime === endTime) {
+          endTime += 0.0001;
+        }
+
         for(let j = 0; j < frames.length; j++) {
           const frame = frames[j];
-          //Safari doesn't put the timestamp frame in the TextTrack
-          // so neither will we
+          // Safari doesn't put the timestamp frame in the TextTrack
           if (!ID3.isTimeStampFrame(frame)) {
             const cue = new Cue(startTime, endTime, '');
             cue.value = frame;

diff --git a/src/demux/id3.js b/src/demux/id3.js
@@ -127,7 +127,7 @@ import {logger} from '../utils/logger';
 
   /**
    * Returns true if the ID3 frame is an Elementary Stream timestamp frame
-   * @param {ID3 frame} frame 
+   * @param {ID3 frame} frame
    */
   static isTimeStampFrame(frame) {
     return (frame && frame.key === 'PRIV' && frame.info === 'com.apple.streaming.transportStreamTimestamp');
@@ -151,7 +151,7 @@ import {logger} from '../utils/logger';
   /**
    * Returns an array of ID3 frames found in all the ID3 tags in the id3Data
    * @param {Uint8Array} id3Data - The ID3 data containing one or more ID3 tags
-   * @return {ID3 frame[]} - Array for ID3 frame objects
+   * @return {ID3 frame[]} - Array of ID3 frame objects
    */
   static getID3Frames(id3Data) {
     let offset = 0;