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<!DOCTYPE html>
<html>
<head>
<title>
audiochannelmerger-input.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>
<script src="/webaudio/resources/merger-testing.js"></script>
</head>
<body>
<script id="layout-test-code">
let audit = Audit.createTaskRunner();
// Task: Check if an inactive input renders a silent mono channel in the
// output.
audit.define('silent-channel', (task, should) => {
testMergerInput(should, {
numberOfChannels: 6,
// Create a mono source buffer filled with '1'.
testBufferContent: [1],
// Connect the output of source into the 4th input of merger.
mergerInputIndex: 3,
// All channels should contain 0, except channel 4 which should be 1.
expected: [0, 0, 0, 1, 0, 0],
}).then(() => task.done());
});
// Task: Check if a stereo input is being down-mixed to mono channel
// correctly based on the mixing rule.
audit.define('stereo-down-mixing', (task, should) => {
testMergerInput(should, {
numberOfChannels: 6,
// Create a stereo buffer filled with '1' and '2' for left and right
// channels respectively.
testBufferContent: [1, 2],
// Connect the output of source into the 1st input of merger.
mergerInputIndex: undefined,
// The result of summed and down-mixed stereo audio should be 1.5.
// (= 1 * 0.5 + 2 * 0.5)
expected: [1.5, 0, 0, 0, 0, 0],
}).then(() => task.done());
});
// Task: Check if 3-channel input gets processed by the 'discrete' mixing
// rule.
audit.define('undefined-channel-layout', (task, should) => {
testMergerInput(should, {
numberOfChannels: 6,
// Create a 3-channel buffer filled with '1', '2', and '3'
// respectively.
testBufferContent: [1, 2, 3],
// Connect the output of source into the 1st input of merger.
mergerInputIndex: undefined,
// The result of summed stereo audio should be 1 because 3-channel is
// not a canonical layout, so the input channel 2 and 3 should be
// dropped by 'discrete' mixing rule.
expected: [1, 0, 0, 0, 0, 0],
}).then(() => task.done());
});
// Task: Merging two inputs into a single stereo stream.
audit.define('merging-to-stereo', (task, should) => {
// For this test, the number of channel should be 2.
let context = new OfflineAudioContext(2, 128, 44100);
let merger = context.createChannelMerger();
let source1 = context.createBufferSource();
let source2 = context.createBufferSource();
// Create a DC offset buffer (mono) filled with 1 and assign it to BS
// nodes.
let positiveDCOffset = createConstantBuffer(context, 128, 1);
let negativeDCOffset = createConstantBuffer(context, 128, -1);
source1.buffer = positiveDCOffset;
source2.buffer = negativeDCOffset;
// Connect: BS#1 => merger_input#0, BS#2 => Inverter => merger_input#1
source1.connect(merger, 0, 0);
source2.connect(merger, 0, 1);
merger.connect(context.destination);
source1.start();
source2.start();
context.startRendering().then(function(buffer) {
// Channel#0 = 1, Channel#1 = -1
should(buffer.getChannelData(0), 'Channel #0').beConstantValueOf(1);
should(buffer.getChannelData(1), 'Channel #1').beConstantValueOf(-1);
task.done();
});
});
audit.run();
</script>
</body>
</html>
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