audioparam-setValueCurve-duration.html

<!DOCTYPE html>
<html>
  <head>
    <title>
      Test setValueCurveAtTime with Huge Duration
    </title>
    <script src="../../resources/testharness.js"></script>
    <script src="../../resources/testharnessreport.js"></script>
    <script src="../resources/audit-util.js"></script>
    <script src="../resources/audit.js"></script>
    <script src="../resources/audioparam-testing.js"></script>
  </head>
  <body>
    <script id="layout-test-code">
      let sampleRate = 48000;
      let renderFrames = 1000;

      let audit = Audit.createTaskRunner();

      audit.define('long duration', (task, should) => {
        // We only need to generate a small number of frames for this test.
        let context = new OfflineAudioContext(1, renderFrames, sampleRate);
        let src = context.createBufferSource();

        // Constant source of amplitude 1, looping.
        src.buffer = createConstantBuffer(context, 1, 1);
        src.loop = true;

        // Automate the gain with a setValueCurve with a very long duration.
        // The duration should produce a frame number greater than 2^64 (larger
        // than the largest size_t value).
        let gain = context.createGain();
        let duration = Math.pow(2, 64);
        let curve = Float32Array.from([0, 1]);
        gain.gain.setValueCurveAtTime(curve, 0, duration);

        // Create the graph and go!
        src.connect(gain);
        gain.connect(context.destination);
        src.start();

        context.startRendering()
            .then(function(result) {
              // Find the maximum value of the buffer.
              let max = Math.max.apply(null, result.getChannelData(0));

              // The automation does linear interpolation between 0 and 1 from
              // time 0 to duration. Hence the max value of the interpolation
              // occurs at the end of the rendering.  Compute this value.

              let expectedMax = (renderFrames / sampleRate) * (1 / duration);

              let message =
                  'setValueCurve([' + curve + '], 0, ' + duration + ')';

              should(max, 'Max amplitude of ' + message)
                  .beLessThanOrEqualTo(expectedMax);
            })
            .then(() => task.done());
      });

      audit.run();
    </script>
  </body>
</html>
chromium/third_party/blink/web_tests/webaudio/AudioParam/audioparam-setValueCurve-duration.html
