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<!DOCTYPE HTML>
<html>
<head>
<title>Test AudioBufferSourceNode</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();
var rate = 44100;
var off = new OfflineAudioContext(1, rate, rate);
var off2 = new OfflineAudioContext(1, rate, rate);
var source = off.createBufferSource();
var source2 = off2.createBufferSource();
// a buffer of a 440Hz at half the length. If we detune by -1200 or set the
// playbackRate to 0.5, we should get 44100 samples back with a sine at 220Hz.
var buf = off.createBuffer(1, rate / 2, rate);
var bufarray = buf.getChannelData(0);
for (var i = 0; i < bufarray.length; i++) {
bufarray[i] = Math.sin(i * 440 * 2 * Math.PI / rate);
}
source.buffer = buf;
source.playbackRate.value = 0.5; // 50% slowdown
source.connect(off.destination);
source.start(0);
source2.buffer = buf;
source2.detune.value = -1200; // one octave -> 50% slowdown
source2.connect(off2.destination);
source2.start(0);
off.startRendering().then((renderedPlaybackRate) => {
// we don't care about comparing the value here, we just want to know whether
// the second part is noisy.
var rmsValue = rms(renderedPlaybackRate, 0, 22050);
ok(rmsValue != 0, "Resampling happened (rms of the second part " + rmsValue + ")");
off2.startRendering().then((renderedDetune) => {
var rmsValue = rms(renderedDetune, 0, 22050);
ok(rmsValue != 0, "Resampling happened (rms of the second part " + rmsValue + ")");
// The two buffers should be the same: detune of -1200 is a 50% slowdown
compareBuffers(renderedPlaybackRate, renderedDetune);
SimpleTest.finish();
});
});
</script>
</pre>
</body>
</html>