audiochannelmerger-input.html

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This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-channelmergernode-interface/audiochannelmerger-input.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>

      audiochannelmerger-input.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>

    <script src="/webaudio/resources/merger-testing.js"></script>

  </head>

  <body>

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

      let audit = Audit.createTaskRunner();

      // Task: Check if an inactive input renders a silent mono channel in the

      // output.

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

        testMergerInput(should, {

          numberOfChannels: 6,

          // Create a mono source buffer filled with '1'.

          testBufferContent: [1],

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

          mergerInputIndex: 3,

          // All channels should contain 0, except channel 4 which should be 1.

          expected: [0, 0, 0, 1, 0, 0],

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

});

      // Task: Check if a stereo input is being down-mixed to mono channel

      // correctly based on the mixing rule.

      audit.define('stereo-down-mixing', (task, should) => {

        testMergerInput(should, {

          numberOfChannels: 6,

          // Create a stereo buffer filled with '1' and '2' for left and right

          // channels respectively.

          testBufferContent: [1, 2],

          // Connect the output of source into the 1st input of merger.

          mergerInputIndex: undefined,

          // The result of summed and down-mixed stereo audio should be 1.5.

          // (= 1 * 0.5 + 2 * 0.5)

          expected: [1.5, 0, 0, 0, 0, 0],

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

});

      // Task: Check if 3-channel input gets processed by the 'discrete' mixing

      // rule.

      audit.define('undefined-channel-layout', (task, should) => {

        testMergerInput(should, {

          numberOfChannels: 6,

          // Create a 3-channel buffer filled with '1', '2', and '3'

          // respectively.

          testBufferContent: [1, 2, 3],

          // Connect the output of source into the 1st input of merger.

          mergerInputIndex: undefined,

          // The result of summed stereo audio should be 1 because 3-channel is

          // not a canonical layout, so the input channel 2 and 3 should be

          // dropped by 'discrete' mixing rule.

          expected: [1, 0, 0, 0, 0, 0],

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

});

      // Task: Merging two inputs into a single stereo stream.

      audit.define('merging-to-stereo', (task, should) => {

        // For this test, the number of channel should be 2.

        let context = new OfflineAudioContext(2, 128, 44100);

        let merger = context.createChannelMerger();

        let source1 = context.createBufferSource();

        let source2 = context.createBufferSource();

        // Create a DC offset buffer (mono) filled with 1 and assign it to BS

        // nodes.

        let positiveDCOffset = createConstantBuffer(context, 128, 1);

        let negativeDCOffset = createConstantBuffer(context, 128, -1);

        source1.buffer = positiveDCOffset;

        source2.buffer = negativeDCOffset;

        // Connect: BS#1 => merger_input#0, BS#2 => Inverter => merger_input#1

        source1.connect(merger, 0, 0);

        source2.connect(merger, 0, 1);

        merger.connect(context.destination);

        source1.start();

        source2.start();

        context.startRendering().then(function(buffer) {

          // Channel#0 = 1, Channel#1 = -1

          should(buffer.getChannelData(0), 'Channel #0').beConstantValueOf(1);

          should(buffer.getChannelData(1), 'Channel #1').beConstantValueOf(-1);

          task.done();

});

});

      audit.run();

    </script>

  </body>

</html>