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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-start.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<head>
<title>
audiobuffersource-start.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/audiobuffersource-testing.js"></script>
</head>
<body>
<script id="layout-test-code">
let audit = Audit.createTaskRunner();
// The following test cases assume an AudioBuffer of length 8 whose PCM
// data is a linear ramp, 0, 1, 2, 3,...
let tests = [
{
description:
'start(when): implicitly play whole buffer from beginning to end',
offsetFrame: 'none',
durationFrames: 'none',
renderFrames: 16,
playbackRate: 1,
expected: [0, 1, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0]
},
{
description:
'start(when, 0): play whole buffer from beginning to end explicitly giving offset of 0',
offsetFrame: 0,
durationFrames: 'none',
renderFrames: 16,
playbackRate: 1,
expected: [0, 1, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0]
},
{
description:
'start(when, 0, 8_frames): play whole buffer from beginning to end explicitly giving offset of 0 and duration of 8 frames',
offsetFrame: 0,
durationFrames: 8,
renderFrames: 16,
playbackRate: 1,
expected: [0, 1, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0]
},
{
description:
'start(when, 4_frames): play with explicit non-zero offset',
offsetFrame: 4,
durationFrames: 'none',
renderFrames: 16,
playbackRate: 1,
expected: [4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
},
{
description:
'start(when, 4_frames, 4_frames): play with explicit non-zero offset and duration',
offsetFrame: 4,
durationFrames: 4,
renderFrames: 16,
playbackRate: 1,
expected: [4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
},
{
description:
'start(when, 7_frames): play with explicit non-zero offset near end of buffer',
offsetFrame: 7,
durationFrames: 1,
renderFrames: 16,
playbackRate: 1,
expected: [7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
},
{
description:
'start(when, 8_frames): play with explicit offset at end of buffer',
offsetFrame: 8,
durationFrames: 0,
renderFrames: 16,
playbackRate: 1,
expected: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
},
{
description:
'start(when, 9_frames): play with explicit offset past end of buffer',
offsetFrame: 8,
durationFrames: 0,
renderFrames: 16,
playbackRate: 1,
expected: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
},
// When the duration exceeds the buffer, just play to the end of the
// buffer. (This is different from the case when we're looping, which is
// tested in loop-comprehensive.)
{
description:
'start(when, 0, 15_frames): play with whole buffer, with long duration (clipped)',
offsetFrame: 0,
durationFrames: 15,
renderFrames: 16,
playbackRate: 1,
expected: [0, 1, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0]
},
// Enable test when AudioBufferSourceNode hack is fixed:
// "start(when, 3_frames, 3_frames): play a middle section with explicit
// offset and duration",
// offsetFrame: 3, durationFrames: 3, renderFrames: 16, playbackRate:
// 1, expected: [4,5,6,7,0,0,0,0,0,0,0,0,0,0,0,0] },
];
let sampleRate = 44100;
let buffer;
let bufferFrameLength = 8;
let testSpacingFrames = 32;
let testSpacingSeconds = testSpacingFrames / sampleRate;
let totalRenderLengthFrames = tests.length * testSpacingFrames;
function runLoopTest(context, testNumber, test) {
let source = context.createBufferSource();
source.buffer = buffer;
source.playbackRate.value = test.playbackRate;
source.connect(context.destination);
// Render each test one after the other, spaced apart by
// testSpacingSeconds.
let startTime = testNumber * testSpacingSeconds;
if (test.offsetFrame == 'none' && test.durationFrames == 'none') {
source.start(startTime);
} else if (test.durationFrames == 'none') {
let offset = test.offsetFrame / context.sampleRate;
source.start(startTime, offset);
} else {
let offset = test.offsetFrame / context.sampleRate;
let duration = test.durationFrames / context.sampleRate;
source.start(startTime, offset, duration);
}
}
audit.define(
'Tests AudioBufferSourceNode start()', function(task, should) {
// Create offline audio context.
let context =
new OfflineAudioContext(1, totalRenderLengthFrames, sampleRate);
buffer = createTestBuffer(context, bufferFrameLength);
for (let i = 0; i < tests.length; ++i)
runLoopTest(context, i, tests[i]);
context.startRendering().then(function(audioBuffer) {
checkAllTests(audioBuffer, should);
task.done();
});
});
audit.run();
</script>
</body>
</html>