51 lines
1.5 KiB
HTML
51 lines
1.5 KiB
HTML
<!DOCTYPE HTML>
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<html>
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<head>
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<meta charset="utf-8">
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<title>Test DynamicsCompressor with Gain</title>
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<script src="/tests/SimpleTest/SimpleTest.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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<script class="testbody" type="text/javascript">
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SimpleTest.waitForExplicitFinish();
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addLoadEvent(function() {
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var samplerate = 44100;
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var context = new OfflineAudioContext(1, samplerate/100, samplerate);
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var osc = context.createOscillator();
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osc.frequency.value = 2400;
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var gain = context.createGain();
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gain.gain.value = 1.5;
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// These numbers are borrowed from the example code on MDN
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// https://developer.mozilla.org/en-US/docs/Web/API/DynamicsCompressorNode
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var compressor = context.createDynamicsCompressor();
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compressor.threshold.value = -50;
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compressor.knee.value = 40;
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compressor.ratio.value = 12;
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compressor.reduction.value = -20;
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compressor.attack.value = 0;
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compressor.release.value = 0.25;
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osc.connect(gain);
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gain.connect(compressor);
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compressor.connect(context.destination);
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osc.start();
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context.startRendering().then(buffer => {
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var peak = Math.max(...buffer.getChannelData(0));
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console.log(peak);
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// These values are experimentally determined. Without dynamics compression
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// the peak should be just under 1.5. We also check for a minimum value
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// to make sure we are not getting all zeros.
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ok(peak >= 0.2 && peak < 1.0, "Peak value should be greater than 0.25 and less than 1.0");
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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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</pre>
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</body>
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