no-dezippering.html

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This test has a WPT meta file that expects 3 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-gainnode-interface/no-dezippering.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>

      Gain Dezippering Test: Dezippering Removed

    </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 audit = Audit.createTaskRunner();

      audit.define(

          {label: 'test0', description: 'Dezippering of GainNode removed'},

          (task, should) => {

            // Only need a few frames to verify that dezippering has been

            // removed from the GainNode.  Sample rate is pretty arbitrary.

            let context = new OfflineAudioContext(1, 1024, 16000);

            // Send a unit source to the gain node so we can measure the effect

            // of the gain node.

            let src = new ConstantSourceNode(context, {offset: 1});

            let g = new GainNode(context, {gain: 1});

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

            context.suspend(RENDER_QUANTUM_FRAMES / context.sampleRate)

                .then(() => {

                  g.gain.value = .5;

})

                .then(() => context.resume());

            src.start();

            context.startRendering()

                .then(audio => {

                  let c = audio.getChannelData(0);

                  // If dezippering has been removed, the gain output should

                  // instantly jump at frame 128 to 0.5.

                  should(c.slice(0, 128), 'output[0:127]').beConstantValueOf(1);

                  should(c.slice(128), 'output[128:]').beConstantValueOf(0.5);

})

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

});

      audit.define(

            label: 'test2',

            description: 'Compare value setter and setValueAtTime'

},

          (task, should) => {

            testWithAutomation(should, {prefix: ''}).then(() => task.done());

});

      audit.define(

          {label: 'test3', description: 'Automation effects'},

          (task, should) => {

            testWithAutomation(should, {

              prefix: 'With modulation: ',

              modulator: true

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

});

      audit.run();

      function testWithAutomation(should, options) {

        // Sample rate must be a power of two to eliminate round-off in

        // computing the time at render quantum boundaries.

        let context = new OfflineAudioContext(2, 1024, 16384);

        let merger = new ChannelMergerNode(context, {numberOfChannels: 2});

        merger.connect(context.destination);

        let src = new OscillatorNode(context);

        let gainTest = new GainNode(context);

        let gainRef = new GainNode(context);

        src.connect(gainTest).connect(merger, 0, 0);

        src.connect(gainRef).connect(merger, 0, 1);

        if (options.modulator) {

          let mod = new OscillatorNode(context, {frequency: 1000});

          let modGain = new GainNode(context);

          mod.connect(modGain);

          modGain.connect(gainTest.gain);

          modGain.connect(gainRef.gain);

          mod.start();

        // Change the gains. Must do the change on a render boundary!

        let changeTime = 3 * RENDER_QUANTUM_FRAMES / context.sampleRate;

        let newGain = .3;

        gainRef.gain.setValueAtTime(newGain, changeTime);

        context.suspend(changeTime)

            .then(() => gainTest.gain.value = newGain)

            .then(() => context.resume());

        src.start();

        return context.startRendering().then(audio => {

          let actual = audio.getChannelData(0);

          let expected = audio.getChannelData(1);

          // The values using the .value setter must be identical to the

          // values using setValueAtTime.

          let match = should(actual, options.prefix + '.value setter output')

                          .beEqualToArray(expected);

          should(

              match,

              options.prefix +

                  '.value setter output matches setValueAtTime output')

              .beTrue();

});

    </script>

  </body>

</html>