nan-param.html - mozsearch

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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-audioparam-interface/nan-param.html - WPT Dashboard Interop Dashboard

<!doctype html>

<html>

  <head>

    <title>Test Flushing of NaN to Zero in AudioParams</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>

      let audit = Audit.createTaskRunner();

      // See

      // https://webaudio.github.io/web-audio-api/#computation-of-value.

//

      // The computed value must replace NaN values in the output with

      // the default value of the param.

      audit.define('AudioParam NaN', async (task, should) => {

        // For testing, we only need a small number of frames; and

        // a low sample rate is perfectly fine.  Use two channels.

        // The first channel is for the AudioParam output.  The

        // second channel is for the AudioParam input.

        let context = new OfflineAudioContext(

            {numberOfChannels: 2, length: 256, sampleRate: 8192});

        let merger = new ChannelMergerNode(

            context, {numberOfInputs: context.destination.channelCount});

        merger.connect(context.destination);

        // A constant source with a huge value.

        let mod = new ConstantSourceNode(context, {offset: 1e30});

        // Gain nodes with a huge positive gain and huge negative

        // gain.  Combined with the huge offset in |mod|, the

        // output of the gain nodes are +Infinity and -Infinity.

        let gainPos = new GainNode(context, {gain: 1e30});

        let gainNeg = new GainNode(context, {gain: -1e30});

        mod.connect(gainPos);

        mod.connect(gainNeg);

        // Connect these to the second merger channel. This is a

        // sanity check that the AudioParam input really is NaN.

        gainPos.connect(merger, 0, 1);

        gainNeg.connect(merger, 0, 1);

        // Source whose AudioParam is connected to the graph

        // that produces NaN values.  Use a non-default value offset

        // just in case something is wrong we get default for some

        // other reason.

        let src = new ConstantSourceNode(context, {offset: 100});

        gainPos.connect(src.offset);

        gainNeg.connect(src.offset);

        // AudioParam output goes to channel 1 of the destination.

        src.connect(merger, 0, 0);

        // Let's go!

        mod.start();

        src.start();

        let buffer = await context.startRendering();

        let input = buffer.getChannelData(1);

        let output = buffer.getChannelData(0);

        // Have to test manually for NaN values in the input because

        // NaN fails all comparisons.

        let isNaN = true;

        for (let k = 0; k < input.length; ++k) {

          if (!Number.isNaN(input[k])) {

            isNaN = false;

            break;

        should(isNaN, 'AudioParam input contains only NaN').beTrue();

        // Output of the AudioParam should have all NaN values

        // replaced by the default.

        should(output, 'AudioParam output')

            .beConstantValueOf(src.offset.defaultValue);

        task.done();

});

      audit.run();

    </script>

  </body>

</html>