k-rate-oscillator.html | Explore in Territory

<!doctype html>
<html>
  <head>
    <title>Test k-rate AudioParams of OscillatorNode</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>
  </head>

  <body>
    <script>
      let audit = Audit.createTaskRunner();

      // Arbitrary sample rate and duration.
      let sampleRate = 8000;

      // Only new a few render quanta to verify things are working.
      let testDuration = 4 * 128 / sampleRate;

      [{name: 'detune', initial: 0, final: 1200}, {
        name: 'frequency',
        initial: 440,
        final: sampleRate / 2
      }].forEach(paramProperty => {
        audit.define(
            'Oscillator k-rate ' + paramProperty.name, (task, should) => {
              let context = new OfflineAudioContext({
                numberOfChannels: 3,
                sampleRate: sampleRate,
                length: testDuration * sampleRate
              });

              let merger = new ChannelMergerNode(
                  context, {numberOfInputs: context.destination.channelCount});
              merger.connect(context.destination);
              let inverter = new GainNode(context, {gain: -1});
              inverter.connect(merger, 0, 2);

              let kRateNode = new OscillatorNode(context);
              let aRateNode = new OscillatorNode(context);

              kRateNode.connect(merger, 0, 0);
              aRateNode.connect(merger, 0, 1);

              kRateNode.connect(merger, 0, 2);
              aRateNode.connect(inverter);

              // Set the rate
              kRateNode[paramProperty.name].automationRate = 'k-rate';

              // Automate the offset
              kRateNode[paramProperty.name].setValueAtTime(
                  paramProperty.initial, 0);
              kRateNode[paramProperty.name].linearRampToValueAtTime(
                  paramProperty.final, testDuration);

              aRateNode[paramProperty.name].setValueAtTime(
                  paramProperty.initial, 0);
              aRateNode[paramProperty.name].linearRampToValueAtTime(
                  paramProperty.final, testDuration);

              kRateNode.start();
              aRateNode.start();

              context.startRendering()
                  .then(audioBuffer => {
                    let kRateOut = audioBuffer.getChannelData(0);
                    let aRateOut = audioBuffer.getChannelData(1);
                    let diff = audioBuffer.getChannelData(2);

                    // Verify that the outputs are different.
                    should(
                        diff,
                        'k-rate ' + paramProperty.name +
                            ': Difference between a-rate and k-rate outputs')
                        .notBeConstantValueOf(0);

                  })
                  .then(() => task.done());
            });
      });


      audit.run();
    </script>
  </body>
</html>
chromium/third_party/blink/web_tests/external/wpt/webaudio/the-audio-api/the-audioparam-interface/k-rate-oscillator.html
