test_adts_dataurl_duration.html

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<head>

<title>Bug 2035059 - ADTS duration via data: URL</title>

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

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

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<body>

<audio id="a"></audio>

<script>

// ADTS has no per-stream duration in the header, so the demuxer estimates

// it from the resource length and falls into the same Infinity-latching

// path as plain CBR mp3 when the resource length isn't reported up front.

const SRC = "adts-cbr.aac";

const EXPECTED = 14.789872;

add_task(async function test_adts_dataurl_duration() {

  const blob = await fetch(SRC).then(r => r.blob());

  const dataUrl = await new Promise(resolve => {

    const fr = new FileReader();

    fr.onload = () => resolve(fr.result);

    fr.readAsDataURL(blob);

});

  const audio = document.getElementById("a");

  audio.src = dataUrl;

  await new Promise((resolve, reject) => {

    audio.addEventListener("canplaythrough", resolve, { once: true });

    audio.addEventListener("error", () => reject(audio.error), { once: true });

});

  // The ADTS demuxer extrapolates duration from a small sample of frame

  // sizes, so the result for variable-rate AAC drifts ~8%. Allow a wide

  // tolerance: this test's job is to catch the Infinity-latching regression,

  // not the unrelated estimation accuracy.

  ok(Number.isFinite(audio.duration),

     "data: URL ADTS duration should be finite, got " + audio.duration);

  ok(Math.abs(audio.duration - EXPECTED) / EXPECTED < 0.15,

     "data: URL ADTS duration should be within 15% of " + EXPECTED + "s, got " +

     audio.duration);

});

</script>

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