audio-track-controller: autoselect default audio track

related to https://github.com/dailymotion/hls.js/issues/30

Author: mangui

src/controller/audio-track-controller.js

@@ -11,8 +11,7 @@ class AudioTrackController extends EventHandler {
   constructor(hls) {
     super(hls, Event.MANIFEST_LOADING,
                Event.MANIFEST_LOADED,
-               Event.AUDIO_TRACK_LOADED
-               );
+               Event.AUDIO_TRACK_LOADED);
     this.tracks = [];
     this.trackId = 0;
   }
@@ -28,8 +27,16 @@ class AudioTrackController extends EventHandler {
   }
 
   onManifestLoaded(data) {
-    this.tracks = data.audioTracks || [];
-    this.hls.trigger(Event.AUDIO_TRACKS_UPDATED, {audioTracks : this.tracks});
+    let tracks = data.audioTracks || [];
+    this.tracks = tracks;
+    this.hls.trigger(Event.AUDIO_TRACKS_UPDATED, {audioTracks : tracks});
+    // loop through available audio tracks and autoselect default if needed
+    tracks.forEach(track => {
+      if(track.default) {
+        this.audioTrack = track.id;
+        return;
+      }
+    });
   }
 
   onAudioTrackLoaded(data) {

src/loader/playlist-loader.js

@@ -107,7 +107,7 @@ class PlaylistLoader extends EventHandler {
   }
 
   parseMasterPlaylistMedia(string, baseurl, type) {
-    let medias = [], result;
+    let medias = [], result, id = 0;
 
     // https://regex101.com is your friend
     const re = /#EXT-X-MEDIA:(.*)/g;
@@ -125,6 +125,7 @@ class PlaylistLoader extends EventHandler {
         if(!media.name) {
             media.name = media.lang;
         }
+        media.id = id++;
         medias.push(media);
       }
     }