silent-inputs.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-waveshapernode-interface/silent-inputs.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>

      Test Silent Inputs to WaveShaperNode

    </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 sampleRate = 16000;

      // Identity curve for the wave shaper: the input value is mapped directly

      // to the output value.

      const identityCurve = [-1, 0, 1];

      const nonZeroCurve = [0.5, 0.5, 0.5];

      promise_test(async (t) => {

        const {context, source, shaper} =

            setupGraph(nonZeroCurve, sampleRate, sampleRate);

        source.offset.setValueAtTime(0, 0);

        const audioBuffer = await context.startRendering();

        assert_array_equals(

            audioBuffer.getChannelData(0),

            new Float32Array(sampleRate).fill(0.5),

            'WaveShaper with silent inputs and curve ' +

                JSON.stringify(shaper.curve));

      }, 'test-0: curve output is non-zero for silent inputs');

      promise_test(async (t) => {

        const {context, source, shaper} =

            setupGraph(nonZeroCurve, sampleRate, sampleRate);

        source.offset.setValueAtTime(0, 0);

        shaper.overSample = '2x';

        const audioBuffer = await context.startRendering();

        assert_array_equals(

            audioBuffer.getChannelData(0),

            new Float32Array(sampleRate).fill(0.5),

            `WaveShaper with ${shaper.overSample} oversample, ` +

                `silent inputs, and curve ${JSON.stringify(shaper.curve)}`);

      }, 'test-1: 2x curve output is non-zero for silent inputs');

      promise_test(async (t) => {

        const {context, source, shaper} =

            setupGraph(nonZeroCurve, sampleRate, sampleRate);

        source.disconnect();

        const audioBuffer = await context.startRendering();

        assert_array_equals(

            audioBuffer.getChannelData(0),

            new Float32Array(sampleRate).fill(0.5),

            'WaveShaper with no inputs and curve ' +

                JSON.stringify(shaper.curve));

      }, 'test-2: curve output is non-zero for no inputs');

      function setupGraph(curve, testFrames, sampleRate) {

        const context = new OfflineAudioContext(1, testFrames, sampleRate);

        const source = new ConstantSourceNode(context);

        const shaper = new WaveShaperNode(context, {curve: curve});

        source.connect(shaper).connect(context.destination);

        return {context: context, source: source, shaper: shaper};

    </script>

  </body>

</html>