servo/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-convolvernode-interface/active-processing.https.html

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<!doctype html>
<html>
<head>
<title>
Test Active Processing for ConvolverNode
</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();
// Arbitrary sample rate. And we only need a few blocks for rendering to
// see if things are working.
let sampleRate = 8000;
let renderLength = 10 * RENDER_QUANTUM_FRAMES;
// Number of frames where the source is active. Fairly arbitrary, but
// should be more than one render quantum and significantly less than
// |renderLength|.
let srcDurationFrames = 131;
// Frame at which the source should be connected to the convolver.
let connectFrame = 2 * RENDER_QUANTUM_FRAMES;
// AudioProcessor that counts the number of channels on its single input.
let filePath =
'../the-audioworklet-interface/processors/input-count-processor.js';
audit.define(
{label: 'Test', description: 'Active processing for ConvolverNode'},
async (task, should) => {
const context = new OfflineAudioContext({
numberOfChannels: 2,
length: renderLength,
sampleRate: sampleRate
});
// Don't mix the inputs to the destination!
context.destination.channelInterpretation = 'discrete';
await context.audioWorklet.addModule(filePath);
// Impulse response for the convolver. Make it stereo so that
// the output is stereo. The length isn't too important.
let response = new AudioBuffer({
numberOfChannels: 2,
length: 150,
sampleRate: context.sampleRate
});
let src = new OscillatorNode(context);
let node = new ConvolverNode(context, {buffer: response});
let counter = new AudioWorkletNode(context, 'counter');
// Just to print a message that we created the graph with a
// convolver in it.
should(() => {
node.connect(counter).connect(context.destination);
}, 'Construction of graph with convolver').notThrow();
// Let the convolver run for a bit and then connect the source
// to it and start the source.
context.suspend(connectFrame / context.sampleRate)
.then(() => {
src.connect(node);
src.start();
// Stop the source after some small number of frames.
src.stop(
context.currentTime +
srcDurationFrames / context.sampleRate);
})
.then(() => context.resume());
const renderedBuffer = await context.startRendering();
const output = renderedBuffer.getChannelData(0);
// The convolver has a stereo response so it will produce
// stereo output for a mono or stereo input. Initially,
// nothing is connected to the convolver so it is not actively
// processing and therefore produces a single channel of
// silence. After a source is connected and started, the
// number of channels must be come 2. When the source stops,
// the convolver node is no longer actively processing and
// must then produce a single channel of silence.
//
// We're not concerned here about when the changes happens. We
// only care that the number of channels changed
// appropriately.
should(output, 'Number of output channels of convolver')
.containValues([1, 2, 1]);
task.done();
});
audit.run();
</script>
</body>
</html>