audiochannelmerger-disconnect.html

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-channelmergernode-interface/audiochannelmerger-disconnect.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>

      audiochannelmerger-disconnect.html

    </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 renderQuantum = 128;

      let numberOfChannels = 2;

      let sampleRate = 44100;

      let renderDuration = 0.5;

      let disconnectTime = 0.5 * renderDuration;

      let audit = Audit.createTaskRunner();

      // Task: Check if the merger outputs a silent channel when an input is

      // disconnected.

      audit.define('silent-disconnect', (task, should) => {

        let context = new OfflineAudioContext(

            numberOfChannels, renderDuration * sampleRate, sampleRate);

        let merger = context.createChannelMerger();

        let source1 = context.createBufferSource();

        let source2 = context.createBufferSource();

        // Create and assign a constant buffer.

        let bufferDCOffset = createConstantBuffer(context, 1, 1);

        source1.buffer = source2.buffer = bufferDCOffset;

        source1.loop = source2.loop = true;

        // Connect the output of source into the 4th input of merger. The merger

        // should produce 6 channel output.

        source1.connect(merger, 0, 0);

        source2.connect(merger, 0, 1);

        merger.connect(context.destination);

        source1.start();

        source2.start();

        // Schedule the disconnection of |source2| at the half of render

        // duration.

        context.suspend(disconnectTime).then(function() {

          source2.disconnect();

          context.resume();

});

        context.startRendering()

            .then(function(buffer) {

              // The entire first channel of the output should be 1.

              should(buffer.getChannelData(0), 'Channel #0')

                  .beConstantValueOf(1);

              // Calculate the first zero index in the second channel.

              let channel1 = buffer.getChannelData(1);

              let disconnectIndex = disconnectTime * sampleRate;

              disconnectIndex = renderQuantum *

                  Math.floor(

                      (disconnectIndex + renderQuantum - 1) / renderQuantum);

              let firstZeroIndex = channel1.findIndex(function(element, index) {

                if (element === 0)

                  return index;

});

              // The second channel should contain 1, and 0 after the

              // disconnection.

              should(channel1, 'Channel #1').containValues([1, 0]);

              should(

                  firstZeroIndex, 'The index of first zero in the channel #1')

                  .beEqualTo(disconnectIndex);

})

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

});

      audit.run();

    </script>

  </body>

</html>