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>

      ChannelMergerNode: Asynchronous disconnect() correctly silences the

      output

    </title>

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

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

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

  </head>

  <body>

    <script>

      const renderQuantum = 128;

      const numberOfChannels = 2;

      const sampleRate = 44100;

      const renderDuration = 0.5;

      const disconnectTime = 0.5 * renderDuration;

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

      // disconnected.

      promise_test(async () => {

        const context = new OfflineAudioContext(

            numberOfChannels, renderDuration * sampleRate, sampleRate);

        const merger = new ChannelMergerNode(context, {numberOfInputs: 6});

        const source1 = new ConstantSourceNode(context, {offset: 1.0});

        const source2 = new ConstantSourceNode(context, {offset: 1.0});

        // Connect the sources to the first two inputs of the 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(() => {

          source2.disconnect();

          context.resume();

});

        const resultBuffer = await context.startRendering();

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

        assert_constant_value(

            resultBuffer.getChannelData(0), 1, 'Channel #0 should be 1.');

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

        const channel1 = resultBuffer.getChannelData(1);

        let disconnectIndex = disconnectTime * sampleRate;

        disconnectIndex = renderQuantum *

            Math.floor((disconnectIndex + renderQuantum - 1) / renderQuantum);

        const firstZeroIndex =

            channel1.findIndex(element => element === 0);

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

        // disconnection.

        assert_constant_value(channel1.subarray(0, disconnectIndex), 1,

            'Channel #1 before disconnect');

        assert_constant_value(channel1.subarray(disconnectIndex), 0,

            'Channel #1 after disconnect');

        assert_equals(firstZeroIndex, disconnectIndex,

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

      }, 'Asynchronous disconnect() correctly silences the output');

    </script>

  </body>

</html>