feat: Add support for ManagedMediaSource 'startstreaming' and 'endstream' event handling

src/playlist-controller.js

@@ -192,6 +192,7 @@
     this.playlistExclusionDuration = playlistExclusionDuration;
     this.maxPlaylistRetries = maxPlaylistRetries;
     this.enableLowInitialPlaylist = enableLowInitialPlaylist;
+    this.hasManagedMediaSource_ = false;
 
     if (this.useCueTags_) {
       this.cueTagsTrack_ = this.tech_.addTextTrack(
@@ -215,6 +216,8 @@
       // Airplay source not yet implemented. Remote playback must be disabled.
       this.tech_.el_.disableRemotePlayback = true;
       this.mediaSource = new window.ManagedMediaSource();
+      this.hasManagedMediaSource_ = true;
+
       videojs.log('Using ManagedMediaSource');
     } else if (window.MediaSource) {
       this.mediaSource = new window.MediaSource();
@@ -232,6 +235,14 @@
     // we don't have to handle sourceclose since dispose will handle termination of
     // everything, and the MediaSource should not be detached without a proper disposal
 
+    if (this.hasManagedMediaSource_) {
+      this.handleStartStreaming_ = this.handleStartStreaming_.bind(this);
+      this.handleEndStreaming_ = this.handleEndStreaming_.bind(this);
+
+      this.mediaSource.addEventListener('startstreaming', this.handleStartStreaming_);
+      this.mediaSource.addEventListener('endstreaming', this.handleEndStreaming_);
+    }
+
     this.seekable_ = createTimeRanges();
     this.hasPlayed_ = false;
 
@@ -1056,14 +1067,31 @@
    */
   load() {
     this.mainSegmentLoader_.load();
+
     if (this.mediaTypes_.AUDIO.activePlaylistLoader) {
       this.audioSegmentLoader_.load();
     }
+
     if (this.mediaTypes_.SUBTITLES.activePlaylistLoader) {
       this.subtitleSegmentLoader_.load();
     }
   }
 
+  /**
+   * Call pause on our SegmentLoaders
+   */
+  pause() {
+    this.mainSegmentLoader_.pause();
+
+    if (this.mediaTypes_.AUDIO.activePlaylistLoader) {
+      this.audioSegmentLoader_.pause();
+    }
+
+    if (this.mediaTypes_.SUBTITLES.activePlaylistLoader) {
+      this.subtitleSegmentLoader_.pause();
+    }
+  }
+
   /**
    * Re-tune playback quality level for the current player
    * conditions. This method will perform destructive actions like removing
@@ -1223,6 +1251,26 @@
       Number.MAX_VALUE : duration;
   }
 
+  /**
+   * Handle the startstreaming event on the ManagedMediaSource.
+   * This event indicates that segment loading should be started/resumed.
+   *
+   * @private
+   */
+  handleStartStreaming_() {
+    this.load();
+  }
+
+  /**
+   * Handle the endstreaming event on the ManagedMediaSource.
+   * This event indicates that segment loading should be paused.
+   *
+   * @private
+   */
+  handleEndStreaming_() {
+    this.pause();
+  }
+
   /**
    * handle the durationchange event on the MediaSource
    *

test/playlist-controller.test.js

@@ -7693,3 +7693,30 @@ QUnit.test('uses ManagedMediaSource only when opted in', function(assert) {
   mmsSpy.restore();
   mms.restore();
 });
+
+QUnit.test('ManagedMediaSource startstreaming and endstreaming events start and pause segment loading respectively', function(assert) {
+  const mms = useFakeManagedMediaSource();
+  const options = {
+    src: 'test.m3u8',
+    tech: this.player.tech_,
+    player_: this.player,
+    experimentalUseMMS: true
+  };
+
+  const controller = new PlaylistController(options);
+  const loadSpy = sinon.spy(controller, 'load');
+  const pauseSpy = sinon.spy(controller, 'pause');
+
+  assert.ok(loadSpy.notCalled, 'Segment loading not started yet');
+  assert.ok(pauseSpy.notCalled, 'Segment loading has not been paused');
+
+  controller.mediaSource.trigger('startstreaming');
+
+  assert.ok(loadSpy.calledOnce, 'Segment loading started on startstreaming event');
+
+  controller.mediaSource.trigger('endstreaming');
+
+  assert.ok(pauseSpy.calledOnce, 'Segment loading paused on endstreaming event');
+
+  mms.restore();
+});