test_video_rate_vfr.html

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<!DOCTYPE html>

<html>

<head>

<title>Test videoRate debug info is the true average frame rate for variable-frame-rate video</title>

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

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

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

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

const testFile = {

  name: "video_rate_vfr.mp4",

  sampleDurationRuns: [

    { sampleCount: 3, sampleDuration: 0.5 },

    { sampleCount: 3, sampleDuration: 1 / 30 },

],

};

// Check that videoRate reports the true average for variable-frame-rate video.

add_task(async function testVideoRateIsTrueAverageForVariableFrameRate() {

  let video = document.createElement("video");

  video.src = testFile.name;

  document.body.appendChild(video);

  await video.play();

ok(

    video.videoWidth > 0 && video.videoHeight > 0,

    `Video should have loaded (${video.videoWidth}x${video.videoHeight})`

);

  info("Play the entire clip before checking videoRate");

  await once(video, "ended");

  let debugData = await SpecialPowers.wrap(video).mozRequestDebugInfo();

  let videoRate = debugData.decoder.reader.videoRate;

  const sampleCount = testFile.sampleDurationRuns.reduce(

    (sum, run) => sum + run.sampleCount,

);

  const totalDuration = testFile.sampleDurationRuns.reduce(

    (sum, run) => sum + run.sampleCount * run.sampleDuration,

);

  const expectedRate = sampleCount / totalDuration;

  info(

    `videoRate=${videoRate} fps, expectedRate=${expectedRate} fps, ` +

      `sampleCount=${sampleCount}, totalDuration=${totalDuration}s`

);

ok(

    Math.abs(videoRate - expectedRate) <= 0.05 * expectedRate,

    `videoRate (${videoRate} fps) should match the true average frame rate ` +

      `sampleCount/totalDuration (${expectedRate} fps)`

);

  removeNodeAndSource(video);

});

</script>

</head>

</html>