test-analyser-output.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-analysernode-interface/test-analyser-output.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<title>Test AnalyserNode passes input to output unmodified</title>

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

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

<script>

  promise_test(async t => {

    // Use 2048 frames for the test render length, matching the default FFT

    // size of AnalyserNode.

    const length = 2048;

    const sampleRate = 48000;

    const context = new OfflineAudioContext(

1,

      length,

      sampleRate

);

    // Generate a 440Hz sine wave to use as the input signal. Using a non-zero

    // signal ensures we can verify the AnalyserNode passes it through

    // unmodified.

    const expectedBuffer = new AudioBuffer({

      numberOfChannels: 1,

      length: length,

      sampleRate: sampleRate

});

    const expectedData = expectedBuffer.getChannelData(0);

    for (let i = 0; i < length; ++i) {

      expectedData[i] = Math.sin(440 * 2 * Math.PI * i / sampleRate);

    const source = new AudioBufferSourceNode(context, {

      buffer: expectedBuffer

});

    const analyser = new AnalyserNode(context);

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

    source.start();

    const renderedBuffer = await context.startRendering();

    const renderedData = renderedBuffer.getChannelData(0);

    assert_equals(

      renderedData.length,

      expectedData.length,

      'Output length matches expected length'

);

    assert_array_approx_equals(

      renderedData,

      expectedData,

      1e-7,

      'AnalyserNode output matches expected input'

);

  }, 'AnalyserNode output passes through input signal unmodified');

</script>