1 files changed, 67 insertions, 0 deletions
diff --git a/media/test/data/eme_player_js/fps_observer.js b/media/test/data/eme_player_js/fps_observer.js
new file mode 100644
index 0000000..8226df8
--- /dev/null
+++ b/media/test/data/eme_player_js/fps_observer.js
@@ -0,0 +1,67 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// FPSObserver observes a <video> and reports decoded FPS, dropped FPS, and
+// total dropped frames during the video playback.
+var FPSObserver = new function() {
+  this.video_ = null;
+  this.decodedFrames_ = 0;
+  this.droppedFrames_ = 0;
+  this.startTime_ = 0;
+  this.intID_ = null;
+}
+
+FPSObserver.observe = function(video) {
+  this.video_ = video;
+  var observer = this;
+  this.video_.addEventListener('playing', function() {
+    observer.onVideoPlaying();
+  });
+
+  this.video_.addEventListener('error', function() {
+    observer.endTest();
+  });
+
+  this.video_.addEventListener('ended', function() {
+    observer.endTest();
+  });
+};
+
+FPSObserver.onVideoPlaying = function() {
+  this.decodedFrames_ = 0;
+  this.droppedFrames_ = 0;
+  this.startTime_ = window.performance.now();
+  this.endTest(true);
+  var observer = this;
+  this.intID_ = window.setInterval(function() {
+      observer.calculateStats();}, 1000);
+};
+
+FPSObserver.calculateStats = function() {
+  if (this.video_.readyState <= HTMLMediaElement.HAVE_CURRENT_DATA ||
+      this.video_.paused || this.video_.ended)
+    return;
+  var currentTime = window.performance.now();
+  var deltaTime = (currentTime - this.startTime_) / 1000;
+  this.startTime_ = currentTime;
+
+  // Calculate decoded frames per sec.
+  var fps = (this.video_.webkitDecodedFrameCount - this.decodedFrames_) /
+             deltaTime;
+  this.decodedFrames_ = this.video_.webkitDecodedFrameCount;
+  fps = fps.toFixed(2);
+  decodedFPSElement.innerHTML = fps;
+
+  // Calculate dropped frames per sec.
+  fps = (this.video_.webkitDroppedFrameCount - this.droppedFrames_) / deltaTime;
+  this.droppedFrames_ = this.video_.webkitDroppedFrameCount;
+  fps = fps.toFixed(2);
+  droppedFPSElement.innerHTML = fps;
+
+  droppedFramesElement.innerHTML = this.droppedFrames_;
+};
+
+FPSObserver.endTest = function() {
+  window.clearInterval(this.intID_);
+};