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<!doctype html>
<html>
<head>
<title>
Test Silent Inputs to WaveShaperNode
</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();
let sampleRate = 16000;
// Identity curve for the wave shaper: the input value is mapped directly
// to the output value.
let identityCurve = [-1, 0, 1];
let nonZeroCurve = [0.5, 0.5, 0.5];
audit.define(
{
label: 'test-0',
description: 'curve output is non-zero for silent inputs'
},
(task, should) => {
let {context, source, shaper} =
setupGraph(nonZeroCurve, sampleRate, sampleRate);
source.offset.setValueAtTime(0, 0);
context.startRendering()
.then(audioBuffer => {
should(
audioBuffer.getChannelData(0),
'WaveShaper with silent inputs and curve ' +
JSON.stringify(shaper.curve))
.beConstantValueOf(0.5);
})
.then(() => task.done());
});
audit.define(
{
label: 'test-1',
description: '2x curve output is non-zero for silent inputs'
},
(task, should) => {
let {context, source, shaper} =
setupGraph(nonZeroCurve, sampleRate, sampleRate);
source.offset.setValueAtTime(0, 0);
shaper.overSample = '2x';
context.startRendering()
.then(audioBuffer => {
should(
audioBuffer.getChannelData(0),
'WaveShaper with ' + shaper.overSample +
' oversample, silent inputs, and curve ' +
JSON.stringify(shaper.curve))
.beConstantValueOf(0.5);
})
.then(() => task.done());
});
audit.define(
{
label: 'test-2',
description: 'curve output is non-zero for no inputs'
},
(task, should) => {
let {context, source, shaper} =
setupGraph(nonZeroCurve, sampleRate, sampleRate);
source.disconnect();
context.startRendering()
.then(audioBuffer => {
should(
audioBuffer.getChannelData(0),
'WaveShaper with no inputs and curve ' +
JSON.stringify(shaper.curve))
.beConstantValueOf(0.5);
})
.then(() => task.done());
});
function setupGraph(curve, testFrames, sampleRate) {
let context = new OfflineAudioContext(1, testFrames, sampleRate);
let source = new ConstantSourceNode(context);
let shaper = new WaveShaperNode(context, {curve: curve});
source.connect(shaper).connect(context.destination);
return {context: context, source: source, shaper: shaper};
}
audit.run();
</script>
</body>
</html>
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