feat(HLS): Add ignoreManifestProgramDateTimeForTypes (#6372)

This new configuration value allows the HLS parser to selectively ignore EXT-X-PROGRAM-DATE-TIME tags on some streams while honoring him for other streams.

externs/shaka/player.js

@@ -982,6 +982,7 @@ shaka.extern.DashManifestConfiguration;
  *   defaultAudioCodec: string,
  *   defaultVideoCodec: string,
  *   ignoreManifestProgramDateTime: boolean,
+ *   ignoreManifestProgramDateTimeForTypes: !Array<string>,
  *   mediaPlaylistFullMimeType: string,
  *   useSafariBehaviorForLive: boolean,
  *   liveSegmentsDelay: number,
@@ -1010,6 +1011,14 @@ shaka.extern.DashManifestConfiguration;
  *   Meant for streams where <code>EXT-X-PROGRAM-DATE-TIME</code> is incorrect
  *   or malformed.
  *   <i>Defaults to <code>false</code>.</i>
+ * @property {!Array.<string>} ignoreManifestProgramDateTimeForTypes
+ *   An array of strings representing types for which
+ *   <code>EXT-X-PROGRAM-DATE-TIME</code> should be ignored. Only used if the
+ *   the main ignoreManifestProgramDateTime is set to false.
+ *   For example, setting this to ['text', 'video'] will cause the PDT values
+ *   text and video streams to be ignored, while still using the PDT values for
+ *   audio.
+ *   <i>Defaults to an empty array.</i>
  * @property {string} mediaPlaylistFullMimeType
  *   A string containing a full mime type, including both the basic mime type
  *   and also the codecs. Used when the HLS parser parses a media playlist

lib/hls/hls_parser.js

@@ -459,7 +459,7 @@ shaka.hls.HlsParser = class {
 
     const {segments, bandwidth} = this.createSegments_(
         playlist, stream, mediaSequenceToStartTime, mediaVariables,
-        streamInfo.getUris);
+        streamInfo.getUris, streamInfo.type);
     if (bandwidth) {
       stream.bandwidth = bandwidth;
     }
@@ -593,6 +593,9 @@ shaka.hls.HlsParser = class {
         this.minSequenceNumber_);
 
     for (const streamInfo of streamInfos) {
+      if (!this.ignoreManifestProgramDateTimeFor_(streamInfo.type)) {
+        continue;
+      }
       const segmentIndex = streamInfo.stream.segmentIndex;
       if (segmentIndex) {
         // Drop any earlier references.
@@ -647,6 +650,9 @@ shaka.hls.HlsParser = class {
     shaka.log.debug('Syncing HLS streams against base time:', lowestSyncTime);
 
     for (const streamInfo of this.uriToStreamInfosMap_.values()) {
+      if (this.ignoreManifestProgramDateTimeFor_(streamInfo.type)) {
+        continue;
+      }
       const segmentIndex = streamInfo.stream.segmentIndex;
       if (segmentIndex != null) {
         // A segment's startTime should be based on its syncTime vs the lowest
@@ -2421,9 +2427,25 @@ shaka.hls.HlsParser = class {
       this.syncStreamsWithSequenceNumber_(streamInfos);
     } else {
       this.syncStreamsWithProgramDateTime_(streamInfos);
+      if (this.config_.hls.ignoreManifestProgramDateTimeForTypes.length > 0) {
+        this.syncStreamsWithSequenceNumber_(streamInfos);
+      }
     }
   }
 
+  /**
+   * @param {string} type
+   * @return {boolean}
+   * @private
+   */
+  ignoreManifestProgramDateTimeFor_(type) {
+    if (this.config_.hls.ignoreManifestProgramDateTime) {
+      return true;
+    }
+    const forTypes = this.config_.hls.ignoreManifestProgramDateTimeForTypes;
+    return forTypes.includes(type);
+  }
+
   /**
    * There are some values on streams that can only be set once we know about
    * both the video and audio content, if present.
@@ -2532,7 +2554,8 @@ shaka.hls.HlsParser = class {
         this.mediaSequenceToStartTimeByType_.get(type) : new Map();
 
     const {segments, bandwidth} = this.createSegments_(
-        playlist, stream, mediaSequenceToStartTime, mediaVariables, getUris);
+        playlist, stream, mediaSequenceToStartTime, mediaVariables, getUris,
+        type);
     if (bandwidth) {
       stream.bandwidth = bandwidth;
     }
@@ -3480,12 +3503,13 @@ shaka.hls.HlsParser = class {
    * @param {!Map.<number, number>} mediaSequenceToStartTime
    * @param {!Map.<string, string>} variables
    * @param {function():!Array.<string>} getUris
+   * @param {string} type
    * @return {{segments: !Array.<!shaka.media.SegmentReference>,
    *          bandwidth: (number|undefined)}}
    * @private
    */
   createSegments_(playlist, stream, mediaSequenceToStartTime, variables,
-      getUris) {
+      getUris, type) {
     /** @type {Array.<!shaka.hls.Segment>} */
     const hlsSegments = playlist.segments;
     goog.asserts.assert(hlsSegments.length, 'Playlist should have segments!');
@@ -3599,7 +3623,7 @@ shaka.hls.HlsParser = class {
         previousReference = reference;
         reference.discontinuitySequence = discontinuitySequence;
 
-        if (this.config_.hls.ignoreManifestProgramDateTime &&
+        if (this.ignoreManifestProgramDateTimeFor_(type) &&
             this.minSequenceNumber_ != null &&
             position < this.minSequenceNumber_) {
           // This segment is ignored as part of our fallback synchronization
@@ -3700,8 +3724,10 @@ shaka.hls.HlsParser = class {
     // skip this step, and wait until we have sync time across stream types.
     const lowestSyncTime = this.lowestSyncTime_;
     if (someSyncTime && lowestSyncTime != Infinity) {
-      for (const reference of references) {
-        reference.syncAgainst(lowestSyncTime);
+      if (!this.ignoreManifestProgramDateTimeFor_(type)) {
+        for (const reference of references) {
+          reference.syncAgainst(lowestSyncTime);
+        }
       }
     }
 

lib/util/player_configuration.js

@@ -150,6 +150,7 @@ shaka.util.PlayerConfiguration = class {
         defaultAudioCodec: 'mp4a.40.2',
         defaultVideoCodec: 'avc1.42E01E',
         ignoreManifestProgramDateTime: false,
+        ignoreManifestProgramDateTimeForTypes: [],
         mediaPlaylistFullMimeType:
             'video/mp2t; codecs="avc1.42E01E, mp4a.40.2"',
         useSafariBehaviorForLive: true,

test/demo/demo_unit.js

@@ -77,6 +77,7 @@ describe('Demo', () => {
           .add('playRangeStart')
           .add('playRangeEnd')
           .add('manifest.dash.keySystemsByURI')
+          .add('manifest.hls.ignoreManifestProgramDateTimeForTypes')
           .add('manifest.mss.keySystemsBySystemId')
           .add('drm.keySystemsMapping')
           .add('manifest.raiseFatalErrorOnManifestUpdateRequestFailure')