chrome/test/data/media/html/audio_latency_perf.html

   1 <!DOCTYPE html>
   2 <html>
   3   <head>
   4     <title>Audio Loop Benchmark</title>
   5     <style>* { font-family: monospace; }</style>
   6   </head>
   7   <body>
   8     <h1>Audio Loop Benchmark</h1>
   9     <p>
  10       Benchmark measuring how fast we can continuously repeat a short sound
  11       clip. In the ideal scenario we'd have zero latency processing script,
  12       seeking back to the beginning of the clip, and resuming audio playback.
  13     </p>
  14
  15     <button onclick="startTest();">Start</button>
  16
  17     <p>
  18       Times Played: <span id="times"></span></span><br>
  19       Clip Duration: <span id="clip"></span></span><br>
  20       Ideal Duration: <span id="ideal"></span><br>
  21       Actual Duration: <span id="actual"></span><br>
  22       Average Latency: <span id="average"></span><br>
  23     </p>
  24
  25     <script>
  26       var TIMES = 50, averageLatency = 0;
  27
  28       function getAndClearElement(id) {
  29         var elem = document.getElementById(id);
  30         elem.innerText = '';
  31         return elem;
  32       }
  33
  34       function startTest() {
  35         var timesElem = getAndClearElement('times');
  36         var clipElem = getAndClearElement('clip');
  37         var idealElem = getAndClearElement('ideal');
  38         var actualElem = getAndClearElement('actual');
  39         var averageElem = getAndClearElement('average');
  40         var buttonElem = document.querySelector('button');
  41
  42         var loopCount = 0, idealDuration = 0, actualDuration = 0;
  43         var startTime;
  44
  45         buttonElem.disabled = true;
  46
  47         function onLoaded() {
  48           idealDuration = Math.round(audio.duration * TIMES * 1000, 0);
  49           idealElem.innerText =  idealDuration + ' ms';
  50           clipElem.innerText = Math.round(audio.duration * 1000, 0) + ' ms';
  51           audio.addEventListener('seeked', onLoop);
  52           startTime = window.performance.now();
  53           audio.play();
  54         }
  55
  56         var audio = document.createElement('audio');
  57         audio.addEventListener('canplaythrough', onLoaded);
  58         audio.loop = true;
  59         audio.src = '../pink_noise_140ms.wav';
  60
  61         function onLoop() {
  62           ++loopCount;
  63           timesElem.innerText = loopCount + '/' + TIMES;
  64           if (loopCount == TIMES) {
  65             actualDuration = window.performance.now() - startTime;
  66             actualElem.innerText = actualDuration + ' ms';
  67             buttonElem.disabled = false;
  68
  69             averageLatency = (actualDuration - idealDuration) / loopCount;
  70             averageElem.innerText = averageLatency + ' ms';
  71
  72             // Let the PyAuto test know we're done testing.
  73             if (window.domAutomationController)
  74               window.domAutomationController.send(true);
  75
  76             audio.pause();
  77           }
  78         }
  79       }
  80     </script>
  81   </body>
  82 </html>