test_analyserNodeMinimum.html

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<!DOCTYPE HTML>

<html>

<head>

  <title>Test AnalyserNode when the input is silent</title>

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

  <script type="text/javascript" src="webaudio.js"></script>

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

</head>

<body>

<pre id="test">

<script class="testbody" type="text/javascript">

SimpleTest.waitForExplicitFinish();

addLoadEvent(function() {

  var ac = new AudioContext();

  var analyser = ac.createAnalyser();

  var constant = ac.createConstantSource();

  var sp = ac.createScriptProcessor(2048, 1, 0);

  constant.offset.value = 0.0;

  constant.connect(analyser)

          .connect(ac.destination);

  constant.connect(sp);

  var buf = new Float32Array(analyser.frequencyBinCount);

  var iteration_count = 10;

  sp.onaudioprocess = function() {

    analyser.getFloatFrequencyData(buf);

    var correct = true;

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

     correct &= buf[i] == -Infinity;

    ok(correct, "silent input process -Infinity in decibel bins");

    if(!(iteration_count--)) {

      sp.onaudioprocess = null;

      constant.stop();

      ac.close();

      SimpleTest.finish();

  constant.start();

});

</script>

</pre>

</body>

</html>