feat: Use ManagedMediaSource when available

externs/managedmediasource.js

@@ -0,0 +1,78 @@
+/*! @license
+ * Shaka Player
+ * Copyright 2016 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Externs for ManagedMediaSource which were missing in the
+ * Closure compiler.
+ *
+ * @externs
+ */
+
+/**
+ * @constructor
+ * @implements {EventTarget}
+ */
+function ManagedMediaSource() {}
+
+/** @override */
+ManagedMediaSource.prototype.addEventListener =
+    function(type, listener, optPptions) {};
+
+/** @override */
+ManagedMediaSource.prototype.removeEventListener =
+    function(type, listener, optPptions) {};
+
+/** @override */
+ManagedMediaSource.prototype.dispatchEvent = function(evt) {};
+
+/** @type {Array<SourceBuffer>} */
+ManagedMediaSource.prototype.sourceBuffers;
+
+/** @type {Array<SourceBuffer>} */
+ManagedMediaSource.prototype.activeSourceBuffers;
+
+/** @type {number} */
+ManagedMediaSource.prototype.duration;
+
+/**
+ * @param {string} type
+ * @return {SourceBuffer}
+ */
+ManagedMediaSource.prototype.addSourceBuffer = function(type) {};
+
+/**
+ * @param {SourceBuffer} sourceBuffer
+ * @return {undefined}
+ */
+ManagedMediaSource.prototype.removeSourceBuffer = function(sourceBuffer) {};
+
+/**
+ * Updates the live seekable range.
+ * @param {number} start
+ * @param {number} end
+ */
+ManagedMediaSource.prototype.setLiveSeekableRange = function(start, end) {};
+
+/**
+ * Clears the live seekable range.
+ * @return {void}
+ */
+ManagedMediaSource.prototype.clearLiveSeekableRange = function() {};
+
+/** @type {string} */
+ManagedMediaSource.prototype.readyState;
+
+/**
+ * @param {string=} optError
+ * @return {undefined}
+ */
+ManagedMediaSource.prototype.endOfStream = function(optError) {};
+
+/**
+ * @param {string} type
+ * @return {boolean}
+ */
+ManagedMediaSource.isTypeSupported = function(type) {};

lib/media/media_source_capabilities.js

@@ -23,9 +23,16 @@ shaka.media.Capabilities = class {
     if (supportMap.has(type)) {
       return supportMap.get(type);
     }
-    const currentSupport = MediaSource.isTypeSupported(type);
-    supportMap.set(type, currentSupport);
-    return currentSupport;
+    if (window.ManagedMediaSource) {
+      const currentSupport = ManagedMediaSource.isTypeSupported(type);
+      supportMap.set(type, currentSupport);
+      return currentSupport;
+    } else if (window.MediaSource) {
+      const currentSupport = MediaSource.isTypeSupported(type);
+      supportMap.set(type, currentSupport);
+      return currentSupport;
+    }
+    return false;
   }
 
   /**

lib/media/media_source_engine.js

@@ -115,7 +115,7 @@ shaka.media.MediaSourceEngine = class {
     /** @private {string} */
     this.url_ = '';
 
-    /** @private {MediaSource} */
+    /** @private {(MediaSource|ManagedMediaSource)} */
     this.mediaSource_ = this.createMediaSource(this.mediaSourceOpen_);
 
     /** @private {boolean} */
@@ -150,25 +150,43 @@ shaka.media.MediaSourceEngine = class {
    * Replaced by unit tests.
    *
    * @param {!shaka.util.PublicPromise} p
-   * @return {!MediaSource}
+   * @return {!(MediaSource|ManagedMediaSource)}
    */
   createMediaSource(p) {
-    const mediaSource = new MediaSource();
+    if (window.ManagedMediaSource) {
+      this.video_.disableRemotePlayback = true;
 
-    // Set up MediaSource on the video element.
-    this.eventManager_.listenOnce(
-        mediaSource, 'sourceopen', () => this.onSourceOpen_(p));
+      const mediaSource = new ManagedMediaSource();
 
-    // Store the object URL for releasing it later.
-    this.url_ = shaka.media.MediaSourceEngine.createObjectURL(mediaSource);
+      this.eventManager_.listenOnce(
+          mediaSource, 'startstreaming', () => p.resolve());
 
-    this.video_.src = this.url_;
+      this.eventManager_.listenOnce(
+          mediaSource, 'sourceopen', () => this.onSourceOpen_());
 
-    return mediaSource;
+      this.url_ = shaka.media.MediaSourceEngine.createObjectURL(mediaSource);
+
+      this.video_.src = this.url_;
+
+      return mediaSource;
+    } else {
+      const mediaSource = new MediaSource();
+
+      // Set up MediaSource on the video element.
+      this.eventManager_.listenOnce(
+          mediaSource, 'sourceopen', () => this.onSourceOpen_(p));
+
+      // Store the object URL for releasing it later.
+      this.url_ = shaka.media.MediaSourceEngine.createObjectURL(mediaSource);
+
+      this.video_.src = this.url_;
+
+      return mediaSource;
+    }
   }
 
   /**
-   * @param {!shaka.util.PublicPromise} p
+   * @param {shaka.util.PublicPromise=} p
    * @private
    */
   onSourceOpen_(p) {
@@ -182,7 +200,9 @@ shaka.media.MediaSourceEngine = class {
     // strong reference to the MediaSource object, and allow it to be
     // garbage-collected later.
     URL.revokeObjectURL(this.url_);
-    p.resolve();
+    if (p) {
+      p.resolve();
+    }
   }
 
   /**

lib/util/platform.js

@@ -23,15 +23,16 @@ shaka.util.Platform = class {
    * @return {boolean}
    */
   static supportsMediaSource() {
+    const mediaSource = window.ManagedMediaSource || window.MediaSource;
     // Browsers that lack a media source implementation will have no reference
     // to |window.MediaSource|. Platforms that we see having problematic media
     // source implementations will have this reference removed via a polyfill.
-    if (!window.MediaSource) {
+    if (!mediaSource) {
       return false;
     }
 
     // Some very old MediaSource implementations didn't have isTypeSupported.
-    if (!MediaSource.isTypeSupported) {
+    if (!mediaSource.isTypeSupported) {
       return false;
     }