test_biquadFilterNodeWithGain.html

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<head>

  <title>Test BiquadFilterNode after a GainNode and tail - Bugs 924286 and 924288</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />

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<pre id="test">

<script src="webaudio.js" type="text/javascript"></script>

<script class="testbody" type="text/javascript">

const signalLength = 2048;

var gTest = {

  length: signalLength,

  numberOfChannels: 1,

  createGraph(context) {

    // Two oscillators scheduled sequentially

    var signalDuration = signalLength / context.sampleRate;

    var osc1 = context.createOscillator();

    osc1.type = "square";

    osc1.start(0);

    osc1.stop(signalDuration / 2);

    var osc2 = context.createOscillator();

    osc2.start(signalDuration / 2);

    osc2.stop(signalDuration);

    // Comparing a biquad on each source with one on both sources checks that

    // the biquad on the first source doesn't shut down early.

    var biquad1 = context.createBiquadFilter();

    osc1.connect(biquad1);

    var biquad2 = context.createBiquadFilter();

    osc2.connect(biquad2);

    var gain = context.createGain();

    gain.gain.value = -1;

    osc1.connect(gain);

    osc2.connect(gain);

    var biquadWithGain = context.createBiquadFilter();

    gain.connect(biquadWithGain);

    // The output of biquadWithGain should be the inverse of the sum of the

    // outputs of biquad1 and biquad2, so blend them together and expect

    // silence.

    var blend = context.createGain();

    biquad1.connect(blend);

    biquad2.connect(blend);

    biquadWithGain.connect(blend);

    return blend;

},

};

runTest();

</script>

</pre>

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