audioworkletnode-channel-count.https.html

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This test has a WPT meta file that expects 3 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-audioworklet-interface/audioworkletnode-channel-count.https.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>

      Test AudioWorkletNode's dynamic channel count feature

    </title>

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

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

    <script src="/webaudio/resources/audit.js"></script>

    <script src="/webaudio/resources/audit-util.js"></script>

  </head>

  <body>

    <script id="layout-test-code">

      let audit = Audit.createTaskRunner();

      // Arbitrary numbers used to align the test with render quantum boundary.

      let sampleRate = RENDER_QUANTUM_FRAMES * 100;

      let renderLength = RENDER_QUANTUM_FRAMES * 2;

      let context;

      let filePath = 'processors/gain-processor.js';

      let testChannelValues = [1, 2, 3];

      // Creates a 3-channel buffer and play with BufferSourceNode. The source

      // goes through a bypass AudioWorkletNode (gain value of 1).

      audit.define('setup-buffer-and-worklet', (task, should) => {

        context = new OfflineAudioContext(testChannelValues.length,

                                          renderLength,

                                          sampleRate);

        // Explicitly sets the destination channelCountMode and

        // channelInterpretation to make sure the result does no mixing.

        context.channeCountMode = 'explicit';

        context.channelInterpretation = 'discrete';

        context.audioWorklet.addModule(filePath).then(() => {

          let testBuffer = createConstantBuffer(context, 1, testChannelValues);

          let sourceNode = new AudioBufferSourceNode(context);

          let gainWorkletNode = new AudioWorkletNode(context, 'gain');

          gainWorkletNode.parameters.get('gain').value = 1.0;

          sourceNode.connect(gainWorkletNode).connect(context.destination);

          // Suspend the context at 128 sample frames and play the source with

          // the assigned buffer.

          context.suspend(RENDER_QUANTUM_FRAMES/sampleRate).then(() => {

            sourceNode.buffer = testBuffer;

            sourceNode.loop = true;

            sourceNode.start();

            context.resume();

});

          task.done();

});

});

      // Verifies if the rendered buffer has all zero for the first half (before

      // 128 samples) and the expected values for the second half.

      audit.define('verify-rendered-buffer', (task, should) => {

          context.startRendering().then(renderedBuffer => {

            testChannelValues.forEach((value, index) => {

              let channelData = renderedBuffer.getChannelData(index);

              should(channelData.subarray(0, RENDER_QUANTUM_FRAMES),

                     'First half of Channel #' + index)

                  .beConstantValueOf(0);

              should(channelData.subarray(RENDER_QUANTUM_FRAMES, renderLength),

                     'Second half of Channel #' + index)

                  .beConstantValueOf(value);

});

            task.done();

});

});

      audit.run();

    </script>

  </body>

</html>