test-analyser-gain.html

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This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-analysernode-interface/test-analyser-gain.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

<head>

  <meta charset="utf-8">

  <script src="/resources/testharness.js"></script>

  <script src="/resources/testharnessreport.js"></script>

  <script>

promise_test(function() {

  // fftSize <= bufferSize so that the time domain data is full of input after

  // processing the buffer.

  const fftSize = 32;

  const bufferSize = 128;

  var context = new OfflineAudioContext(1, bufferSize, 48000);

  var analyser1 = context.createAnalyser();

  analyser1.fftSize = fftSize;

  analyser1.connect(context.destination);

  var analyser2 = context.createAnalyser();

  analyser2.fftSize = fftSize;

  var gain = context.createGain();

  gain.gain.value = 2.0;

  gain.connect(analyser1);

  gain.connect(analyser2);

  // Create a DC input to make getFloatTimeDomainData() output consistent at

  // any time.

  var buffer = context.createBuffer(1, 1, context.sampleRate);

  buffer.getChannelData(0)[0] = 1.0 / gain.gain.value;

  var source = context.createBufferSource();

  source.buffer = buffer;

  source.loop = true;

  source.connect(gain);

  source.start();

  return context.startRendering().then(function(buffer) {

    assert_equals(buffer.getChannelData(0)[0], 1.0, "analyser1 output");

    var data = new Float32Array(1);

    analyser1.getFloatTimeDomainData(data);

    assert_equals(data[0], 1.0, "analyser1 time domain data");

    analyser2.getFloatTimeDomainData(data);

    assert_equals(data[0], 1.0, "analyser2 time domain data");

});

}, "Test effect of AnalyserNode on GainNode output");

  </script>

</head>

</body>

</html>