зеркало из https://github.com/mozilla/gecko-dev.git
67 строки
2.0 KiB
HTML
67 строки
2.0 KiB
HTML
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<!DOCTYPE HTML>
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<html>
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<head>
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<title>Test AudioBufferSourceNode</title>
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<script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
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<script type="text/javascript" src="webaudio.js"></script>
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<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
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</head>
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<body>
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<pre id="test">
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<script class="testbody" type="text/javascript">
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SimpleTest.waitForExplicitFinish();
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var rate = 44100;
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var off = new OfflineAudioContext(1, rate, rate);
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var off2 = new OfflineAudioContext(1, rate, rate);
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var source = off.createBufferSource();
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var source2 = off2.createBufferSource();
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// a buffer of a 440Hz at half the length. If we detune by -1200 or set the
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// playbackRate to 0.5, we should get 44100 samples back with a sine at 220Hz.
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var buf = off.createBuffer(1, rate / 2, rate);
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var bufarray = buf.getChannelData(0);
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for (var i = 0; i < bufarray.length; i++) {
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bufarray[i] = Math.sin(i * 440 * 2 * Math.PI / rate);
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}
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source.buffer = buf;
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source.playbackRate.value = 0.5; // 50% slowdown
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source.connect(off.destination);
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source.start(0);
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source2.buffer = buf;
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source2.detune.value = -1200; // one octave -> 50% slowdown
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source2.connect(off2.destination);
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source2.start(0);
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var finished = 0;
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function finish() {
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finished++;
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if (finished == 2) {
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SimpleTest.finish();
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}
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}
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off.startRendering().then((renderedPlaybackRate) => {
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// we don't care about comparing the value here, we just want to know whether
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// the second part is noisy.
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var rmsValue = rms(renderedPlaybackRate, 0, 22050);
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ok(rmsValue != 0, "Resampling happened (rms of the second part " + rmsValue + ")");
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off2.startRendering().then((renderedDetune) => {
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var rmsValue = rms(renderedDetune, 0, 22050);
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ok(rmsValue != 0, "Resampling happened (rms of the second part " + rmsValue + ")");
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// The two buffers should be the same: detune of -1200 is a 50% slowdown
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compareBuffers(renderedPlaybackRate, renderedDetune);
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SimpleTest.finish();
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});
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});
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</script>
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</pre>
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</body>
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</html>
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