Make buffering runtime-configurable.

Closes shaka-project#49.

Change-Id: I954e247e83a27c5f9f2e56bb7b57c714c1d8db71

lib/media/stream.js

@@ -109,7 +109,7 @@ shaka.media.Stream =
   this.streamInfo_ = null;
 
   /** @private {number} */
-  this.bufferingGoal_ = shaka.media.Stream.BUFFER_SIZE_SECONDS_;
+  this.initialBufferSize_ = 0;
 
   /** @private {?function()} */
   this.nextSwitch_ = null;
@@ -161,10 +161,9 @@ shaka.media.Stream.State_ = {
 /**
  * The amount of content we will try to buffer by default, after startup.
  *
- * @private {number}
- * @const
+ * @type {number}
  */
-shaka.media.Stream.BUFFER_SIZE_SECONDS_ = 15.0;
+shaka.media.Stream.bufferSizeSeconds = 15.0;
 
 
 /**
@@ -239,7 +238,7 @@ shaka.media.Stream.prototype.start = function(streamInfo, initialBufferSize) {
   this.streamInfo_ = streamInfo;
   this.type_ = streamInfo.mimeType.split('/')[0];
   this.state_ = Stream.State_.INITIALIZING;
-  this.bufferingGoal_ = Math.max(this.bufferingGoal_, initialBufferSize);
+  this.initialBufferSize_ = initialBufferSize;
 
   var expectedFirstTimestamp;
 
@@ -371,7 +370,8 @@ shaka.media.Stream.prototype.switch = function(streamInfo, immediate) {
         } else {
           var availableBitsPerSecond = this.estimator_.getBandwidth();
           var requiredBitsPerSecond = streamInfo.bandwidth;
-          var estimatedFetchBits = this.bufferingGoal_ * requiredBitsPerSecond;
+          var estimatedFetchBits =
+              this.getBufferingGoal_() * requiredBitsPerSecond;
           var estimatedFetchLatency =
               estimatedFetchBits / availableBitsPerSecond;
           var bufferedAhead =
@@ -389,7 +389,7 @@ shaka.media.Stream.prototype.switch = function(streamInfo, immediate) {
 
         // Fetch new segments to meet the buffering requirement.
         var segmentRange = streamInfo.segmentIndex.getRangeForInterval(
-            switchTime, this.bufferingGoal_);
+            switchTime, this.getBufferingGoal_());
         if (!segmentRange) {
           return Promise.reject(new Error('No segments available.'));
         }
@@ -569,7 +569,7 @@ shaka.media.Stream.prototype.onUpdate_ = function() {
 
   var currentTime = this.video_.currentTime;
   var bufferedAhead = this.sbm_.bufferedAheadOf(currentTime);
-  if (bufferedAhead >= this.bufferingGoal_) {
+  if (bufferedAhead >= this.getBufferingGoal_()) {
     // We don't need to make a request right now, so check again in a second.
     this.updateTimerId_ = window.setTimeout(this.onUpdate_.bind(this), 1000);
     return;
@@ -628,6 +628,19 @@ shaka.media.Stream.prototype.onUpdate_ = function() {
 };
 
 
+/**
+ * Returns the max of shaka.media.Stream.bufferSizeSeconds and
+ *    the initalBufferSize of an instance.
+ *
+ * @return {number}
+ * @private
+ */
+shaka.media.Stream.prototype.getBufferingGoal_ = function() {
+  return Math.max(
+      shaka.media.Stream.bufferSizeSeconds, this.initialBufferSize_);
+};
+
+
 /**
  * Returns the index of the SegmentReference corresponding to the first
  * unbuffered segment starting at |time|. -1 is returned if there are no

lib/player/player.js

@@ -645,6 +645,28 @@ shaka.player.Player.prototype.seek = function(seconds) {
 };
 
 
+/**
+ * @param {number} bufferSize The amount of content streams will try to buffer
+ *    in seconds.
+ * @export
+ */
+shaka.player.Player.prototype.setStreamBufferSize = function(bufferSize) {
+  shaka.asserts.assert(bufferSize >= 0);
+  var buffer = (bufferSize < 0) ? 0 : bufferSize;
+  shaka.media.Stream.bufferSizeSeconds = buffer;
+};
+
+
+/**
+ * Returns the seconds of content streams will try to buffer.
+ * @return {number}
+ * @export
+ */
+shaka.player.Player.prototype.getStreamBufferSize = function() {
+  return shaka.media.Stream.bufferSizeSeconds;
+};
+
+
 /**
  * @param {number} timeout Timeout for LicenseRequests in ms.
  * @export

spec/player_integration.js

@@ -17,6 +17,7 @@
  */
 
 goog.require('shaka.dash.MpdRequest');
+goog.require('shaka.media.Stream');
 goog.require('shaka.player.DashVideoSource');
 goog.require('shaka.player.Player');
 goog.require('shaka.polyfill.installAll');
@@ -669,6 +670,29 @@ describe('Player', function() {
     });
   });
 
+  it('sets buffer size on streams', function(done) {
+    player.setStreamBufferSize(5);
+    var mediaSource = new MediaSource();
+    video.src = window.URL.createObjectURL(mediaSource);
+    mediaSource.addEventListener('sourceopen', function() {
+      var buffer = mediaSource.addSourceBuffer(
+          'video/mp4; codecs="avc1.4d4015"');
+      var stream = new shaka.media.Stream(
+          player, video, mediaSource, buffer, estimator);
+      expect(stream.getBufferingGoal_()).toEqual(5);
+      video.src = '';
+      player.setStreamBufferSize(15);
+      done();
+    });
+  });
+
+  it('gets streams buffer size', function() {
+    player.setStreamBufferSize(5);
+    expect(player.getStreamBufferSize()).toEqual(5);
+    player.setStreamBufferSize(15);
+    expect(player.getStreamBufferSize()).toEqual(15);
+  });
+
   it('sets timeout on LicenseRequests', function() {
     player.setLicenseRequestTimeout(5);
     var request = new shaka.util.LicenseRequest(