test_MediaSource_capture_gc.html

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<!DOCTYPE HTML>

<html>

<head>

  <title>Test garbage collection of captured stream, when playing a MediaSource</title>

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

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

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

</head>

<pre id="test">

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

function forceGC() {

  SpecialPowers.gc();

  SpecialPowers.forceGC();

  SpecialPowers.forceCC();

SimpleTest.waitForExplicitFinish();

window.onload = async function() {

// Create an infinite source using a MediaSource

let el = document.createElement("audio");

const ms = new MediaSource();

el.src = URL.createObjectURL(ms);

await once(ms, "sourceopen");

const sb = ms.addSourceBuffer("video/mp4");

await fetchAndLoad(sb, "bipbop/bipbop_audio", ["init"], ".mp4");

await fetchAndLoad(sb, "bipbop/bipbop_audio", range(1, 11), ".m4s");

setInterval(async function() {

  sb.timestampOffset =  sb.buffered.end(sb.buffered.length - 1);

  await fetchAndLoad(sb, "bipbop/bipbop_audio", range(1, 11), ".m4s");

}, 8000);

el.play();

// Analyze the media element output.

const ac = new AudioContext;

const analyzer = ac.createAnalyser();

// bug 1703603

const stream = el.mozCaptureStreamUntilEnded();

const mss = ac.createMediaStreamSource(stream);

const gain = ac.createGain();

// compensate mochitest volume scaling, but don't connect to the AudioContext's

// destination to avoid noise during the test

gain.gain.value = 90;

mss.connect(gain).connect(analyzer);

// Drop the media element reference: it is supposed to be kept alive by the

// AudioContext via the `MediaStream`.

el = null;

// check whether the media element is still playing using the analyzer, spam the

// GC to ensure all refs are kept.

const buf = new Float32Array(analyzer.frequencyBinCount);

const startTime = Date.now();

function checkNonSilent() {

  analyzer.getFloatFrequencyData(buf);

  forceGC();

  // Wait a good 20 seconds.

  if (Date.now() - startTime < 2000) {

    requestAnimationFrame(checkNonSilent);

  } else {

    ok(true, "All objects were kept alive.");

    SimpleTest.finish();

checkNonSilent();

</script>

</pre>

</body>

</html>