audiobuffersource-null.html

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This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-null.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>

      Test ABSN Outputs Silence if buffer is null

    </title>

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

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

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

  </head>

  <body>

    <script>

      promise_test(async () => {

        // Create test context.  Length and sampleRate are pretty arbitrary, but

        // we don't need either to be very large.

        const context = new OfflineAudioContext(

            {numberOfChannels: 1, length: 1024, sampleRate: 8192});

        // Just create a constant buffer for testing.  Anything will do as long

        // as the buffer contents are not identically zero.

        const audioBuffer =

            new AudioBuffer({length: 10, sampleRate: context.sampleRate});

        const audioBufferSourceNode = new AudioBufferSourceNode(context);

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

        audioBufferSourceNode.buffer = audioBuffer;

        // This is the important part.  Setting the buffer to null after setting

        // it to something else should cause the source to produce silence.

        audioBufferSourceNode.buffer = null;

        audioBufferSourceNode.start();

        audioBufferSourceNode.connect(context.destination);

        const renderedBuffer = await context.startRendering();

        // Since the buffer is null, the output of the source should be

        // silence.

        const actual = renderedBuffer.getChannelData(0);

        assert_constant_value(actual, 0, 'ABSN output');

      }, 'ABSN with null buffer');

    </script>

  </body>

</html>