feat(HLS): Parse SAMPLE-RATE attribute (shaka-project#5375)

lib/hls/hls_parser.js

@@ -686,15 +686,13 @@ shaka.hls.HlsParser = class {
       // Make the stream info, with those values.
       const streamInfo = await this.convertParsedPlaylistIntoStreamInfo_(
           playlist, uri, uri, codecs, type, language, primary, name,
-          channelsCount, closedCaptions, characteristics, forced, spatialAudio,
-          mimeType);
+          channelsCount, closedCaptions, characteristics, forced, sampleRate,
+          spatialAudio, mimeType);
       this.uriToStreamInfosMap_.set(uri, streamInfo);
 
       if (type == 'video') {
         this.addVideoAttributes_(streamInfo.stream, width, height,
             /* frameRate= */ null, /* videoRange= */ null);
-      } else if (type == 'audio') {
-        streamInfo.stream.audioSamplingRate = sampleRate;
       }
 
       // Wrap the stream from that stream info with a variant.
@@ -1547,6 +1545,21 @@ shaka.hls.HlsParser = class {
     return count;
   }
 
+  /**
+   * Get the sample rate information for an HLS audio track.
+   *
+   * @param {!shaka.hls.Tag} tag
+   * @return {?number}
+   * @private
+   */
+  getSampleRate_(tag) {
+    const sampleRate = tag.getAttributeValue('SAMPLE-RATE');
+    if (!sampleRate) {
+      return null;
+    }
+    return parseInt(sampleRate, 10);
+  }
+
   /**
    * Get the spatial audio information for an HLS audio track.
    * In HLS the channels field indicates the number of audio channels that the
@@ -1801,12 +1814,13 @@ shaka.hls.HlsParser = class {
 
     const forcedAttrValue = tag.getAttributeValue('FORCED');
     const forced = forcedAttrValue == 'YES';
+    const sampleRate = type == 'audio' ? this.getSampleRate_(tag) : null;
     // TODO: Should we take into account some of the currently ignored
     // attributes: INSTREAM-ID, Attribute descriptions: https://bit.ly/2lpjOhj
     const streamInfo = this.createStreamInfo_(
         verbatimMediaPlaylistUri, codecs, type, language, primary, name,
         channelsCount, /* closedCaptions= */ null, characteristics, forced,
-        spatialAudio);
+        sampleRate, spatialAudio);
     if (this.groupIdToStreamInfosMap_.has(groupId)) {
       this.groupIdToStreamInfosMap_.get(groupId).push(streamInfo);
     } else {
@@ -1853,7 +1867,8 @@ shaka.hls.HlsParser = class {
     const streamInfo = this.createStreamInfo_(
         verbatimImagePlaylistUri, codecs, type, language, /* primary= */ false,
         name, /* channelsCount= */ null, /* closedCaptions= */ null,
-        characteristics, /* forced= */ false, /* spatialAudio= */ false);
+        characteristics, /* forced= */ false, /* sampleRate= */ null,
+        /* spatialAudio= */ false);
 
     // TODO: This check is necessary because of the possibility of multiple
     // calls to createStreamInfoFromImageTag_ before either has resolved.
@@ -1917,7 +1932,7 @@ shaka.hls.HlsParser = class {
         codecs, type, /* language= */ 'und', /* primary= */ false,
         /* name= */ null, /* channelcount= */ null, closedCaptions,
         /* characteristics= */ null, /* forced= */ false,
-        /* spatialAudio= */ false);
+        /* sampleRate= */ null, /* spatialAudio= */ false);
     // TODO: This check is necessary because of the possibility of multiple
     // calls to createStreamInfoFromVariantTag_ before either has resolved.
     if (this.uriToStreamInfosMap_.has(verbatimMediaPlaylistUri)) {
@@ -1940,13 +1955,14 @@ shaka.hls.HlsParser = class {
    * @param {Map.<string, string>} closedCaptions
    * @param {?string} characteristics
    * @param {boolean} forced
+   * @param {?number} sampleRate
    * @param {boolean} spatialAudio
    * @return {!shaka.hls.HlsParser.StreamInfo}
    * @private
    */
   createStreamInfo_(verbatimMediaPlaylistUri, codecs, type, language,
       primary, name, channelsCount, closedCaptions, characteristics, forced,
-      spatialAudio) {
+      sampleRate, spatialAudio) {
     // TODO: Refactor, too many parameters
     const initialMediaPlaylistUri = shaka.hls.Utils.constructAbsoluteUri(
         this.masterPlaylistUri_, verbatimMediaPlaylistUri);
@@ -1955,7 +1971,8 @@ shaka.hls.HlsParser = class {
     // So we start out with a stream object that does not contain the actual
     // segment index, then download when createSegmentIndex is called.
     const stream = this.makeStreamObject_(codecs, type, language, primary, name,
-        channelsCount, closedCaptions, characteristics, forced, spatialAudio);
+        channelsCount, closedCaptions, characteristics, forced, sampleRate,
+        spatialAudio);
     const streamInfo = {
       stream,
       type,
@@ -1996,7 +2013,7 @@ shaka.hls.HlsParser = class {
       const realStreamInfo = await this.convertParsedPlaylistIntoStreamInfo_(
           playlist, verbatimMediaPlaylistUri, absoluteMediaPlaylistUri, codecs,
           type, language, primary, name, channelsCount, closedCaptions,
-          characteristics, forced, spatialAudio);
+          characteristics, forced, sampleRate, spatialAudio);
       if (abortSignal.aborted) {
         return;
       }
@@ -2239,15 +2256,16 @@ shaka.hls.HlsParser = class {
    * @param {Map.<string, string>} closedCaptions
    * @param {?string} characteristics
    * @param {boolean} forced
+   * @param {?number} sampleRate
    * @param {boolean} spatialAudio
    * @param {(string|undefined)} mimeType
    * @return {!Promise.<!shaka.hls.HlsParser.StreamInfo>}
    * @private
    */
   async convertParsedPlaylistIntoStreamInfo_(playlist, verbatimMediaPlaylistUri,
       absoluteMediaPlaylistUri, codecs, type, language, primary, name,
-      channelsCount, closedCaptions, characteristics, forced, spatialAudio,
-      mimeType = undefined) {
+      channelsCount, closedCaptions, characteristics, forced, sampleRate,
+      spatialAudio, mimeType = undefined) {
     if (playlist.type != shaka.hls.PlaylistType.MEDIA) {
       // EXT-X-MEDIA and EXT-X-IMAGE-STREAM-INF tags should point to media
       // playlists.
@@ -2317,7 +2335,8 @@ shaka.hls.HlsParser = class {
         this.getNextMediaSequenceAndPart_(mediaSequenceNumber, segments);
 
     const stream = this.makeStreamObject_(codecs, type, language, primary, name,
-        channelsCount, closedCaptions, characteristics, forced, spatialAudio);
+        channelsCount, closedCaptions, characteristics, forced, sampleRate,
+        spatialAudio);
     stream.segmentIndex = segmentIndex;
     stream.encrypted = encrypted;
     stream.drmInfos = drmInfos;
@@ -2401,12 +2420,13 @@ shaka.hls.HlsParser = class {
    * @param {Map.<string, string>} closedCaptions
    * @param {?string} characteristics
    * @param {boolean} forced
+   * @param {?number} sampleRate
    * @param {boolean} spatialAudio
    * @return {!shaka.extern.Stream}
    * @private
    */
   makeStreamObject_(codecs, type, language, primary, name, channelsCount,
-      closedCaptions, characteristics, forced, spatialAudio) {
+      closedCaptions, characteristics, forced, sampleRate, spatialAudio) {
     // Fill out a "best-guess" mimeType, for now. It will be replaced once the
     // stream is lazy-loaded.
     const mimeType = this.guessMimeTypeBeforeLoading_(type, codecs) ||
@@ -2439,7 +2459,7 @@ shaka.hls.HlsParser = class {
       roles: characteristics ? characteristics.split(',') : [],
       forced,
       channelsCount,
-      audioSamplingRate: null,
+      audioSamplingRate: sampleRate,
       spatialAudio,
       closedCaptions,
       hdr: undefined,

test/hls/hls_parser_unit.js

@@ -150,7 +150,7 @@ describe('HlsParser', () => {
     const master = [
       '#EXTM3U\n',
       '#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aud1",LANGUAGE="eng",',
-      'CHANNELS="16/JOC",URI="audio"\n',
+      'CHANNELS="16/JOC",SAMPLE-RATE="48000",URI="audio"\n',
       '#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="sub1",LANGUAGE="eng",',
       'URI="text"\n',
       '#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="sub2",LANGUAGE="es",',
@@ -192,6 +192,7 @@ describe('HlsParser', () => {
         variant.addPartialStream(ContentType.AUDIO, (stream) => {
           stream.language = 'en';
           stream.channelsCount = 16;
+          stream.audioSamplingRate = 48000;
           stream.spatialAudio = true;
           stream.mime('audio/mp4', 'mp4a');
         });