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62 lines
1.5 KiB
HTML
62 lines
1.5 KiB
HTML
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<!DOCTYPE HTML>
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<html>
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<head>
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<title>Test AudioParam with pre-gain </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 ctx = new AudioContext();
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var source = ctx.createOscillator();
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var lfo = ctx.createOscillator();
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var lfoIntensity = ctx.createGain();
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var effect = ctx.createGain();
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var sp = ctx.createScriptProcessor(2048, 1);
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source.frequency.value = 440;
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lfo.frequency.value = 2;
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// Very low gain, so the LFO should have very little influence
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// on the source, its RMS value should be close to the nominal value
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// for a sine wave.
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lfoIntensity.gain.value = 0.0001;
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lfo.connect(lfoIntensity);
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lfoIntensity.connect(effect.gain);
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source.connect(effect);
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effect.connect(sp);
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sp.onaudioprocess = function(e) {
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var buffer = e.inputBuffer.getChannelData(0);
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var rms = 0;
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for (var i = 0; i < buffer.length; i++) {
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rms += buffer[i] * buffer[i];
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}
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rms /= buffer.length;
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rms = Math.sqrt(rms);
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// 1 / Math.sqrt(2) is the theoretical RMS value for a sine wave.
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ok(fuzzyCompare(rms, 1 / Math.sqrt(2)),
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"Gain correctly applied to the AudioParam.");
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ctx = null;
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sp.onaudioprocess = null;
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lfo.stop(0);
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source.stop(0);
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SimpleTest.finish();
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}
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lfo.start(0);
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source.start(0);
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</script>
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</pre>
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</body>
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