simple-input-output.https.html

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This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-audioworklet-interface/simple-input-output.https.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>Test Simple AudioWorklet I/O</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>

      // Arbitrary sample rate

      const sampleRate = 48000;

      // The offset to be applied by the worklet to its inputs.

      const offset = 1;

      // Location of the worklet's code

      const filePath = 'processors/add-offset.js';

      let audit = Audit.createTaskRunner();

      // Context to be used for the tests.

      let context;

      audit.define('Initialize worklet', (task, should) => {

        // Two channels for testing.  Channel 0 is the output of the

        // AudioWorklet.  Channel 1 is the oscillator so we can compare

        // the outputs.

        context = new OfflineAudioContext(

            {numberOfChannels: 2, length: sampleRate, sampleRate: sampleRate});

        // Load up the code for the worklet.

        should(

            context.audioWorklet.addModule(filePath),

            'Creation of AudioWorklet')

            .beResolved()

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

});

      audit.define(

          {label: 'test', description: 'Simple AudioWorklet I/O'},

          (task, should) => {

            let merger = new ChannelMergerNode(

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

            merger.connect(context.destination);

            let src = new OscillatorNode(context);

            let worklet = new AudioWorkletNode(

                context, 'add-offset-processor',

                {processorOptions: {offset: offset}});

            src.connect(worklet).connect(merger, 0, 0);

            src.connect(merger, 0, 1);

            // Start and stop the source.  The stop time is fairly arbitrary,

            // but use a render quantum boundary for simplicity.

            const stopFrame = RENDER_QUANTUM_FRAMES;

            src.start(0);

            src.stop(stopFrame / context.sampleRate);

            context.startRendering()

                .then(buffer => {

                  let ch0 = buffer.getChannelData(0);

                  let ch1 = buffer.getChannelData(1);

                  let shifted = ch1.slice(0, stopFrame).map(x => x + offset);

                  // The initial part of the output should be the oscillator

                  // shifted by |offset|.

                  should(

                      ch0.slice(0, stopFrame),

                      `AudioWorklet output[0:${stopFrame - 1}]`)

                      .beCloseToArray(shifted, {absoluteThreshold: 0});

                  // Output should be constant after the source has stopped.

                  should(

                      ch0.slice(stopFrame),

                      `AudioWorklet output[${stopFrame}:]`)

                      .beConstantValueOf(offset);

})

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

});

      audit.run();

    </script>

  </body>

</html>