<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
  <title>Test DynamicsCompressor with Gain</title>
  <script src="/tests/SimpleTest/SimpleTest.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
</head>
<body>
<script class="testbody" type="text/javascript">
SimpleTest.waitForExplicitFinish();

addLoadEvent(function() {
  var samplerate = 44100;
  var context = new OfflineAudioContext(1, samplerate/100, samplerate);

  var osc = context.createOscillator();
  osc.frequency.value = 2400;

  var gain = context.createGain();
  gain.gain.value = 1.5;

  // These numbers are borrowed from the example code on MDN
  // https://developer.mozilla.org/en-US/docs/Web/API/DynamicsCompressorNode
  var compressor = context.createDynamicsCompressor();
  compressor.threshold.value = -50;
  compressor.knee.value = 40;
  compressor.ratio.value = 12;
  compressor.reduction.value = -20;
  compressor.attack.value = 0;
  compressor.release.value = 0.25;

  osc.connect(gain);
  gain.connect(compressor);
  compressor.connect(context.destination);
  osc.start();

  context.startRendering().then(buffer => {
    var peak = Math.max(...buffer.getChannelData(0));
    console.log(peak);
    // These values are experimentally determined. Without dynamics compression
    // the peak should be just under 1.5. We also check for a minimum value
    // to make sure we are not getting all zeros.
    ok(peak >= 0.2 && peak < 1.0, "Peak value should be greater than 0.25 and less than 1.0");
    SimpleTest.finish();
  });
});
</script>
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