transferred-buffer-output.html

Enable keyboard shortcuts

This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-convolvernode-interface/transferred-buffer-output.html - WPT Dashboard Interop Dashboard

<!doctype html>

<html>

  <head>

    <title>

      Test Convolver Output with Transferred Buffer

    </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>

      // Arbitrary sample rate.

      const sampleRate = 16000;

      // Number of frames to render.  Just need to have at least 2 render

      // quanta.

      const lengthInFrames = 10 * RENDER_QUANTUM_FRAMES;

      let audit = Audit.createTaskRunner();

      // Buffer to use for the impulse response of a ConvolverNode.

      let impulseBuffer;

      // This sets up a worker to receive one channel of an AudioBuffer.

      function setUpWorkerForTest() {

        impulseBuffer = new AudioBuffer({

          numberOfChannels: 2,

          length: 2 * RENDER_QUANTUM_FRAMES,

          sampleRate: sampleRate

});

        // Just fill the buffer with a constant value; the contents shouldn't

        // matter for this test since we're transferring one of the channels.

        impulseBuffer.getChannelData(0).fill(1);

        impulseBuffer.getChannelData(1).fill(2);

        // We're going to transfer channel 0 to the worker, making it

        // unavailable for the convolver

        let data = impulseBuffer.getChannelData(0).buffer;

        let string = [

          'onmessage = function(e) {', '    postMessage(\'done\');', '};'

        ].join('\n');

        let blobURL = URL.createObjectURL(new Blob([string]));

        let worker = new Worker(blobURL);

        worker.onmessage = workerReply;

        worker.postMessage(data, [data]);

      function workerReply() {

        // Worker has received the message.  Run the test.

        audit.run();

      audit.define(

            label: 'Test Convolver with transferred buffer',

            description: 'Output should be all zeroes'

},

          async (task, should) => {

            // Two channels so we can capture the output of the convolver with a

            // stereo convolver.

            let context = new OfflineAudioContext({

              numberOfChannels: 2,

              length: lengthInFrames,

              sampleRate: sampleRate

});

            // Use a simple constant source so we easily check that the

            // convolver output is correct.

            let source = new ConstantSourceNode(context);

            // Create the convolver with the desired impulse response and

            // disable normalization so we can easily check the output.

            let conv = new ConvolverNode(

                context, {disableNormalization: true, buffer: impulseBuffer});

            source.connect(conv).connect(context.destination);

            source.start();

            let renderedBuffer = await context.startRendering();

            // Get the actual data

            let c0 = renderedBuffer.getChannelData(0);

            let c1 = renderedBuffer.getChannelData(1);

            // Since one channel was transferred, we must behave as if all were

            // transferred.  Hence, the output should be all zeroes for both

            // channels.

            should(c0, `Convolver channel 0 output[0:${c0.length - 1}]`)

                .beConstantValueOf(0);

            should(c1, `Convolver channel 1 output[0:${c1.length - 1}]`)

                .beConstantValueOf(0);

            task.done();

});

      setUpWorkerForTest();

    </script>

  </body>

</html>