test_bug966247.html

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<!DOCTYPE HTML>

<html>

<head>

  <title>Test whether an audio file played with a volume set to 0 plays silence</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />

</head>

<body>

<audio preload=none src="ting-48k-1ch.ogg" controls> </audio>

<script>

  SimpleTest.waitForExplicitFinish();

  var count = 20;

  function isSilent(b) {

    for (var i = 0; i < b.length; i++) {

      if (b[i] != 0.0) {

        return false;

    return true;

  var a = document.getElementsByTagName("audio")[0];

  a.volume = 0.0;

  var ac = new AudioContext();

  var measn = ac.createMediaElementSource(a);

  var sp = ac.createScriptProcessor();

  sp.onaudioprocess = function(e) {

    var inputBuffer = e.inputBuffer.getChannelData(0);

    ok(isSilent(inputBuffer), "The volume is set to 0, so all the elements of the buffer are supposed to be equal to 0.0");

  // Connect the MediaElementAudioSourceNode to the ScriptProcessorNode to check

  // the audio volume.

  measn.connect(sp);

  a.play();

  a.addEventListener("ended", function() {

    sp.onaudioprocess = null;

    SimpleTest.finish();

});

</script>

</body>

</html>