k-rate-oscillator.html

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This test has a WPT meta file that expects 2 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-audioparam-interface/k-rate-oscillator.html - WPT Dashboard Interop Dashboard

<!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>

  </head>

  <body>

    <script>

      // Arbitrary sample rate and duration.

      const sampleRate = 8000;

      // Only new a few render quanta to verify things are working.

      const testDuration = 4 * 128 / sampleRate;

      [{name: 'detune', initial: 0, final: 1200}, {

        name: 'frequency',

        initial: 440,

        final: sampleRate / 2}].forEach((paramProperty) => {

        promise_test(async () => {

          const context = new OfflineAudioContext({

            numberOfChannels: 3,

            sampleRate: sampleRate,

            length: testDuration * sampleRate

});

          const merger = new ChannelMergerNode(

              context, {numberOfInputs: context.destination.channelCount});

          merger.connect(context.destination);

          const inverter = new GainNode(context, {gain: -1});

          inverter.connect(merger, 0, 2);

          const kRateNode = new OscillatorNode(context);

          const 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();

          const audioBuffer = await context.startRendering();

          const diff = audioBuffer.getChannelData(2);

          // Verify that the outputs are different.

          assert_not_constant_value_of(

              diff, 0,

              `k-rate ${paramProperty.name}: ` +

                  `Difference between a-rate and k-rate outputs`);

        }, `Oscillator k-rate ${paramProperty.name}`);

});

    </script>

  </body>

</html>