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<!DOCTYPE html>
<html>
<head>
<title>
Gain Dezippering Test: Dezippering Removed
</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/webaudio/resources/audit-util.js"></script>
<script src="/webaudio/resources/audit.js"></script>
</head>
<body>
<script id="layout-test-code">
let audit = Audit.createTaskRunner();
audit.define(
{label: 'test0', description: 'Dezippering of GainNode removed'},
(task, should) => {
// Only need a few frames to verify that dezippering has been
// removed from the GainNode. Sample rate is pretty arbitrary.
let context = new OfflineAudioContext(1, 1024, 16000);
// Send a unit source to the gain node so we can measure the effect
// of the gain node.
let src = new ConstantSourceNode(context, {offset: 1});
let g = new GainNode(context, {gain: 1});
src.connect(g).connect(context.destination);
context.suspend(RENDER_QUANTUM_FRAMES / context.sampleRate)
.then(() => {
g.gain.value = .5;
})
.then(() => context.resume());
src.start();
context.startRendering()
.then(audio => {
let c = audio.getChannelData(0);
// If dezippering has been removed, the gain output should
// instantly jump at frame 128 to 0.5.
should(c.slice(0, 128), 'output[0:127]').beConstantValueOf(1);
should(c.slice(128), 'output[128:]').beConstantValueOf(0.5);
})
.then(() => task.done());
});
audit.define(
{
label: 'test2',
description: 'Compare value setter and setValueAtTime'
},
(task, should) => {
testWithAutomation(should, {prefix: ''}).then(() => task.done());
});
audit.define(
{label: 'test3', description: 'Automation effects'},
(task, should) => {
testWithAutomation(should, {
prefix: 'With modulation: ',
modulator: true
}).then(() => task.done());
});
audit.run();
function testWithAutomation(should, options) {
// Sample rate must be a power of two to eliminate round-off in
// computing the time at render quantum boundaries.
let context = new OfflineAudioContext(2, 1024, 16384);
let merger = new ChannelMergerNode(context, {numberOfChannels: 2});
merger.connect(context.destination);
let src = new OscillatorNode(context);
let gainTest = new GainNode(context);
let gainRef = new GainNode(context);
src.connect(gainTest).connect(merger, 0, 0);
src.connect(gainRef).connect(merger, 0, 1);
if (options.modulator) {
let mod = new OscillatorNode(context, {frequency: 1000});
let modGain = new GainNode(context);
mod.connect(modGain);
modGain.connect(gainTest.gain);
modGain.connect(gainRef.gain);
mod.start();
}
// Change the gains. Must do the change on a render boundary!
let changeTime = 3 * RENDER_QUANTUM_FRAMES / context.sampleRate;
let newGain = .3;
gainRef.gain.setValueAtTime(newGain, changeTime);
context.suspend(changeTime)
.then(() => gainTest.gain.value = newGain)
.then(() => context.resume());
src.start();
return context.startRendering().then(audio => {
let actual = audio.getChannelData(0);
let expected = audio.getChannelData(1);
// The values using the .value setter must be identical to the
// values using setValueAtTime.
let match = should(actual, options.prefix + '.value setter output')
.beEqualToArray(expected);
should(
match,
options.prefix +
'.value setter output matches setValueAtTime output')
.beTrue();
});
}
</script>
</body>
</html>
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