SourceBuffer-appendWindowEnd-rounding.html

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This WPT test may be referenced by the following Test IDs:
- /media-source/SourceBuffer-appendWindowEnd-rounding.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

<head>

<title>Test appendWindowEnd and frame end timestamp rounding</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="mediasource-util.js"></script>

</head>

<body>

</body>

<script>

const fps = 24;

const frames_per_keyframe = 8;

const default_sample_duration = 512;

const earliest_presentation_time = 1024;

const frame0_offset = earliest_presentation_time / default_sample_duration;

// Presentation positions of the 8 frames in a segment are

// 0, 4, 2, 1, 3, 7, 6, 5.

let media;

promise_test(async t => {

  media = await new Promise(

    r => MediaSourceUtil.fetchManifestAndData(

t,

      `mp4/test-v-128k-320x240-${fps}fps-${frames_per_keyframe}kfr-manifest.json`,

      (type, data) => r({type, data})));

}, 'setup');

async function append_frames({t, last_frame_pos}) {

  assert_implements_optional(MediaSource.isTypeSupported(media.type),

                             'type supported');

  const v = document.createElement('video');

  const v_watcher = new EventWatcher(t, v, ['error']);

  document.body.appendChild(v);

  const media_source = new MediaSource();

  const media_source_watcher =

        new EventWatcher(t, media_source, ['sourceopen']);

  v.src = URL.createObjectURL(media_source);

  await media_source_watcher.wait_for('sourceopen');

  const source_buffer = media_source.addSourceBuffer(media.type);

  assert_equals(source_buffer.mode, 'segments', 'source_buffer.mode');

  const source_buffer_watcher =

        new EventWatcher(t, source_buffer, ['updateend']);

  // This is intentionally a sum of double precision representations of

  // "presentation timestamp and frame duration" to match frame end timestamp

  // in

  // https://w3c.github.io/media-source/#sourcebuffer-coded-frame-processing

  source_buffer.appendWindowEnd = last_frame_pos / fps + 1 / fps;

  source_buffer.appendBuffer(media.data);

  await source_buffer_watcher.wait_for('updateend');

  assert_approx_equals(source_buffer.buffered.start(0),

                       frame0_offset / fps,

                       1e-6,

                       'source_buffer.buffered.start(0) after append');

  assert_approx_equals(

    source_buffer.buffered.end(source_buffer.buffered.length - 1),

    source_buffer.appendWindowEnd,

    1e-6,

    'source_buffer.buffered.end() after append');

  media_source.endOfStream();

  assert_equals(media_source.duration,

                source_buffer.buffered.end(source_buffer.buffered.length - 1),

                'media_source.duration == buffered.end');

  assert_equals(v.duration, media_source.duration,

                'v.duration == media_source.duration');

};

// The first frame has presentation timestamp 2 frame durations after zero.

//

// The ninth frame has presentation timestamp 10 frame durations after zero

// and is a keyframe.  The double precision sum of double presentation

// representations of its timestamp and frame duration is greater than the

// double precision representation of the tenth frame's timestamp.

// i.e 10/24 + 1/24 > 11/24, which would round down if rounded to

// nearest microseconds.

//

// The eighteenth frame has presentation timestamp 22 frame durations after

// zero.  (Frames are not in presentation order.)  It is immediately after a

// keyframe and so is found before the need random access point flag is set to

// true on applying appendWindowEnd.  The double precision sum of double

// presentation representations of its timestamp and frame duration is less

// than the double precision representation of the tenth frame's timestamp.

// i.e 22/24 + 1/24 < 23/24, which would round down if rounded to nearest

// microseconds.

for (const last_frame_pos of [10, 22]) {

  promise_test(

    t => append_frames({t, last_frame_pos}),

    `last frame at ${last_frame_pos}`);

</script>

</html>