blob: aa6378f0ac7ad31f054e335e1ea1d57072c7c202 [file] [log] [blame]
<!DOCTYPE html>
<html>
<head>
<title>
dynamicscompressor-simple.html
</title>
<script src="../../imported/w3c/web-platform-tests/resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="../resources/audit-util.js"></script>
<script src="../resources/audit.js"></script>
</head>
<body>
<script id="layout-test-code">
let audit = Audit.createTaskRunner();
let context;
let compressor;
let sampleRate = 44100;
let lengthInSeconds = 1;
let renderedData;
// This threshold experimentally determined. It depends on the the gain
// value of the gain node below and the dynamics compressor. When the
// DynamicsCompressor had the pre-emphasis filters, the peak value is
// about 0.21. Without it, the peak is about 0.84.
let peakThreshold = 0.83;
function checkResult(renderedBuffer, should) {
renderedData = renderedBuffer.getChannelData(0);
// Search for a peak in the last part of the data.
let startSample = sampleRate * (lengthInSeconds - .1);
let endSample = renderedData.length;
let k;
let peak = -1;
for (k = startSample; k < endSample; ++k) {
let sample = Math.abs(renderedData[k]);
if (peak < sample)
peak = sample;
}
should(peak >= peakThreshold, 'Pre-emphasis effect not applied')
.beTrue();
should(compressor.reduction !== 0, 'Reduction value changed').beTrue();
}
audit.define(
{
label: 'test',
description: 'Test pre-emphasis in DynamicsCompressor is removed'
},
function(task, should) {
context = new OfflineAudioContext(
1, sampleRate * lengthInSeconds, sampleRate);
// Connect an oscillator to a gain node to the compressor. The
// oscillator frequency is set to a high value for the (original)
// emphasis to kick in. The gain is a little extra boost to get the
// compressor enabled.
//
let osc = context.createOscillator();
osc.frequency.value = 15000;
let gain = context.createGain();
gain.gain.value = 1.5;
compressor = context.createDynamicsCompressor();
osc.connect(gain);
gain.connect(compressor);
compressor.connect(context.destination);
osc.start();
context.startRendering()
.then(buffer => checkResult(buffer, should))
.then(() => task.done());
;
});
audit.run();
</script>
</body>
</html>