<!DOCTYPE html>
<!--
Tests that AudioChannelSplitter works correctly.
-->
<html>
<head>
<title>
audiochannelsplitter.html
</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 = 44100.0;
let lengthInSampleFrames = 512;
let context = 0;
let sourceBuffer;
let sourceNode;
let channelSplitter;
let channelMerger;
function createStereoBufferWithDCOffset(length, sampleRate, offset) {
let buffer = context.createBuffer(2, length, sampleRate);
let n = buffer.length;
let channelL = buffer.getChannelData(0);
let channelR = buffer.getChannelData(1);
for (let i = 0; i < n; ++i) {
channelL[i] = offset;
channelR[i] = -1.0 * offset;
}
return buffer;
}
// checkResult() checks that the rendered buffer is stereo and that the
// left channel is all -1 and right channel all +1. In other words, we've
// reversed the order of the two channels.
function checkResult(buffer, should) {
let success = true;
if (buffer.numberOfChannels == 2) {
let bufferDataL = buffer.getChannelData(0);
let bufferDataR = buffer.getChannelData(1);
success = should(bufferDataL, 'Left channel').beConstantValueOf(-1) &&
success;
success = should(bufferDataR, 'Right channel').beConstantValueOf(1) &&
success;
} else {
success = false;
}
should(success, 'Left and right channels were exchanged')
.message('correctly', 'incorrectly');
}
audit.define(
{
label: 'construction',
description: 'Construction of ChannelSplitterNode'
},
function(task, should) {
// Create stereo offline audio context.
context =
new OfflineAudioContext(2, lengthInSampleFrames, sampleRate);
let splitternode;
should(() => {
let splitternode = context.createChannelSplitter(0);
}, 'createChannelSplitter(0)').throw(DOMException, 'IndexSizeError');
should(() => {
splitternode = context.createChannelSplitter(33);
}, 'createChannelSplitter(33)').throw(DOMException, 'IndexSizeError');
should(() => {
splitternode = context.createChannelSplitter(32);
}, 'splitternode = context.createChannelSplitter(32)').notThrow();
should(splitternode.numberOfOutputs, 'splitternode.numberOfOutputs')
.beEqualTo(32);
should(splitternode.numberOfInputs, 'splitternode.numberOfInputs')
.beEqualTo(1)
should(() => {
splitternode = context.createChannelSplitter();
}, 'splitternode = context.createChannelSplitter()').notThrow();
should(splitternode.numberOfOutputs, 'splitternode.numberOfOutputs')
.beEqualTo(6);
task.done();
});
audit.define(
{
label: 'functionality',
description: 'Functionality of ChannelSplitterNode'
},
function(task, should) {
// Create a stereo buffer, with all +1 values in left channel, all
// -1 in right channel.
sourceBuffer = createStereoBufferWithDCOffset(
lengthInSampleFrames, sampleRate, 1);
sourceNode = context.createBufferSource();
sourceNode.buffer = sourceBuffer;
// Create a channel splitter and connect it so that it split the
// stereo stream into two mono streams.
channelSplitter = context.createChannelSplitter(2);
sourceNode.connect(channelSplitter);
// Create a channel merger to merge the output of channel splitter.
channelMerger = context.createChannelMerger();
channelMerger.connect(context.destination);
// When merging, exchange channel layout: left->right, right->left
channelSplitter.connect(channelMerger, 0, 1);
channelSplitter.connect(channelMerger, 1, 0);
sourceNode.start(0);
context.startRendering()
.then(buffer => checkResult(buffer, should))
.then(task.done.bind(task));
});
audit.run();
</script>
</body>
</html>
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