maxdelay-rounding.html

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This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-delaynode-interface/maxdelay-rounding.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>

      Test DelayNode when maxDelayTime requires rounding

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

      let sampleRate = 44100;

      let inputLengthSeconds = 1;

      let renderLengthSeconds = 2;

      // Delay for one second plus 0.4 of a sample frame, to test that

      // DelayNode is properly rounding up when calculating its buffer

      // size (crbug.com/1065110).

      let delayTimeSeconds = 1 + 0.4 / sampleRate;

      let audit = Audit.createTaskRunner();

      audit.define(

            label: 'maxdelay-rounding',

            description: 'Test DelayNode when maxDelayTime requires rounding',

},

          (task, should) => {

            let context = new OfflineAudioContext({

                numberOfChannels: 1,

                length: sampleRate * renderLengthSeconds,

                sampleRate: sampleRate,

});

            // Create a constant source to use as input.

            let src = new ConstantSourceNode(context);

            // Create a DelayNode to delay for delayTimeSeconds.

            let delay = new DelayNode(context, {

                maxDelayTime: delayTimeSeconds,

                delayTime: delayTimeSeconds,

});

            src.connect(delay).connect(context.destination);

            src.start();

            context.startRendering()

                .then(renderedBuffer => {

                  let renderedData = renderedBuffer.getChannelData(0);

                  // The first delayTimeSeconds of output should be silent.

                  let expectedSilentFrames = Math.floor(

                      delayTimeSeconds * sampleRate);

                  should(

                      renderedData.slice(0, expectedSilentFrames),

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

                      .beConstantValueOf(0);

                  // The rest should be non-silent: that is, there should

                  // be at least one non-zero sample.  (Any reasonable

                  // interpolation algorithm will make all these samples

                  // non-zero, but I don't think that's guaranteed by the

                  // spec, so we use a conservative test for now.)

                  should(

                      renderedData.slice(expectedSilentFrames),

                      `output[${expectedSilentFrames}:]`)

                      .notBeConstantValueOf(0);

})

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

});

      audit.run();

    </script>

  </body>

</html>