test_audioContextParams_sampleRate.html

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<head>

  <script type="application/javascript" src="mediaStreamPlayback.js"></script>

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<pre id="test">

<script>

/* import-globals-from ../../webrtc/tests/mochitests/mediaStreamPlayback.js */

createHTML({

  title: "Parallel MTG by setting AudioContextParam sample rate",

  bug: "1387454",

  visible: true

});

runTest(async () => {

  // Test an AudioContext of specific sample rate.

  // Verify that the oscillator produces a tone.

  const rate1 = 500;

  const ac1 = new AudioContext({sampleRate: 44100});

  const dest_ac1 = ac1.createMediaStreamDestination();

  const osc_ac1 = ac1.createOscillator();

  osc_ac1.frequency.value = rate1;

  osc_ac1.connect(dest_ac1);

  osc_ac1.start(0);

  const analyser = new AudioStreamAnalyser(ac1, dest_ac1.stream);

  analyser.enableDebugCanvas();

  await analyser.waitForAnalysisSuccess( array => {

    const freg_50Hz   = array[analyser.binIndexForFrequency(50)];

    const freq_rate1  = array[analyser.binIndexForFrequency(rate1)];

    const freq_4000Hz = array[analyser.binIndexForFrequency(4000)];

    info("Analysing audio frequency - low:target1:high = "

            + freg_50Hz + ':' + freq_rate1 + ':' + freq_4000Hz);

    return freg_50Hz < 50 && freq_rate1 > 200 && freq_4000Hz < 50;

})

  osc_ac1.stop();

  // Same test using a  new AudioContext of different sample rate.

  const rate2 = 1500;

  const ac2 = new AudioContext({sampleRate: 48000});

  const dest_ac2 = ac2.createMediaStreamDestination();

  const osc_ac2 = ac2.createOscillator();

  osc_ac2.frequency.value = rate2;

  osc_ac2.connect(dest_ac2);

  osc_ac2.start(0);

  const analyser2 = new AudioStreamAnalyser(ac2, dest_ac2.stream);

  analyser2.enableDebugCanvas();

  await analyser2.waitForAnalysisSuccess( array => {

    const freg_50Hz   = array[analyser2.binIndexForFrequency(50)];

    const freq_rate2  = array[analyser2.binIndexForFrequency(rate2)];

    const freq_4000Hz = array[analyser2.binIndexForFrequency(4000)];

    info("Analysing audio frequency - low:target2:high = "

            + freg_50Hz + ':' + freq_rate2 + ':' + freq_4000Hz);

    return freg_50Hz < 50 && freq_rate2 > 200 && freq_4000Hz < 50;

})

  osc_ac2.stop();

  // Two AudioContexts with different sample rate cannot communicate.

  mustThrowWith("Connect nodes with different sample rate", "NotSupportedError",

                () => ac2.createMediaStreamSource(dest_ac1.stream));

  // Two AudioContext with the same sample rate can communicate.

  const ac3 = new AudioContext({sampleRate: 48000});

  const dest_ac3 = ac3.createMediaStreamDestination();

  ac2.createMediaStreamSource(dest_ac3.stream);

  ok(true, "Connect nodes with the same sample rate is ok");

  mustThrowWith("Invalid zero samplerate", "NotSupportedError",

    () => new AudioContext({sampleRate: 0}));

  mustThrowWith("Invalid negative samplerate", "NotSupportedError",

    () => new AudioContext({sampleRate: -1}));

});

</script>

</pre>

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