test-analyser-minimum.html | Explore in Territory

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>Test AnalyserNode when the input is silent</title>
  <meta name="timeout" content="long">
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
  <script>
    setup({ single_test: true });
    var ac = new AudioContext();
    var analyser = ac.createAnalyser();
    var constant = ac.createConstantSource();
    var sp = ac.createScriptProcessor(2048, 1, 1);

    constant.offset.value = 0.0;

    constant.connect(analyser).connect(ac.destination);

    constant.connect(sp).connect(ac.destination);

    var buf = new Float32Array(analyser.frequencyBinCount);
    var iteration_count = 10;
    sp.onaudioprocess = function() {
      analyser.getFloatFrequencyData(buf);
      var correct = true;
      for (var i = 0; i < buf.length; i++) {
        correct &= buf[i] == -Infinity;
      }
      assert_true(!!correct, "silent input process -Infinity in decibel bins");
      if (!iteration_count--) {
        sp.onaudioprocess = null;
        constant.stop();
        ac.close();
        done();
      }
    };

    constant.start();
  </script>
</head>
</body>
</html>

chromium/third_party/blink/web_tests/external/wpt/webaudio/the-audio-api/the-analysernode-interface/test-analyser-minimum.html