remoting/webapp/media_source_renderer.js

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 'use strict';
   6
   7 /** @suppress {duplicate} */
   8 var remoting = remoting || {};
   9
  10 /**
  11  * @param {HTMLMediaElement} videoTag <video> tag to render to.
  12  * @constructor
  13  */
  14 remoting.MediaSourceRenderer = function(videoTag) {
  15   /** @type {HTMLMediaElement} */
  16   this.video_ = videoTag;
  17
  18   /** @type {MediaSource} */
  19   this.mediaSource_ = null;
  20
  21   /** @type {SourceBuffer} */
  22   this.sourceBuffer_ = null;
  23
  24   /** @type {!Array.<ArrayBuffer>} Queue of pending buffers that haven't been
  25    * processed . */
  26   this.buffers_ = [];
  27 }
  28
  29 /**
  30  * @param {string} format Format of the stream.
  31  */
  32 remoting.MediaSourceRenderer.prototype.reset = function(format) {
  33   // Create a new MediaSource instance.
  34   this.sourceBuffer_ = null;
  35   this.mediaSource_ = new MediaSource();
  36   this.mediaSource_.addEventListener('sourceopen',
  37                                      this.onSourceOpen_.bind(this, format));
  38   this.mediaSource_.addEventListener('sourceclose', function(e) {
  39     console.error("MediaSource closed unexpectedly.");
  40   });
  41   this.mediaSource_.addEventListener('sourceended', function(e) {
  42     console.error("MediaSource ended unexpectedly.");
  43   });
  44
  45   // Start playback from new MediaSource.
  46   this.video_.src =
  47       /** @type {string} */(
  48           window.URL.createObjectURL(/** @type {!Blob} */(this.mediaSource_)));
  49   this.video_.play();
  50 }
  51
  52 /**
  53  * @param {string} format
  54  * @private
  55  */
  56 remoting.MediaSourceRenderer.prototype.onSourceOpen_ = function(format) {
  57   this.sourceBuffer_ =
  58       this.mediaSource_.addSourceBuffer(format);
  59
  60   this.sourceBuffer_.addEventListener(
  61       'updateend', this.processPendingData_.bind(this));
  62   this.processPendingData_();
  63 }
  64
  65 /**
  66  * @private
  67  */
  68 remoting.MediaSourceRenderer.prototype.processPendingData_ = function() {
  69   if (this.sourceBuffer_) {
  70     while (this.buffers_.length > 0 && !this.sourceBuffer_.updating) {
  71       // TODO(sergeyu): Figure out the way to determine when a frame is rendered
  72       // and use it to report performance statistics.
  73       this.sourceBuffer_.appendBuffer(
  74           /** @type {ArrayBuffer} */(this.buffers_.shift()));
  75     }
  76   }
  77 }
  78
  79 /**
  80  * @param {ArrayBuffer} data
  81  */
  82 remoting.MediaSourceRenderer.prototype.onIncomingData = function(data) {
  83   this.buffers_.push(data);
  84   this.processPendingData_();
  85 }
  86