Source code

Revision control

Copy as Markdown

Other Tools

Test Info: Errors

<title>Seamless looping test cancel looping - no future frame</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 type="application/javascript">
* This test aims to check whether the future frames, which are the frames
* beyond EOS and will be played in the next round of looping, would be discared
* correctly if we cancel looping in the first looping round.
add_task(async function testSeamlessLoopingVideoCancelLoopingDiscardFutureFrames() {
info(`create video and play it`);
let video = document.createElement('video');
video.loop = true;
video.src = "gizmo.mp4";
// speed up the test.
video.playbackRate = 2;
info(`wait until the video reaches to near end`);
let checkPoint1, checkPoint2;
await new Promise(r => {
video.ontimeupdate = _ => {
// When media almost reaches to the end, the audio track should already
// reach to the end before and started storing some future frames for next
// round of looping.
if (video.currentTime > video.duration - 1.5) {
info(`cancel looping`);
video.loop = false;
video.ontimeupdate = null;
checkPoint1 = new Date();
// Because we've canceled looping, playback should reach to the end soon
// (less than 0.5 seconds, but we use 1 second as a threshold to avoid
// intermittent failure) But if we didn't discard future frames correctly,
// that would cause that the video plays more audio frames and requires more
// time to reach the end. Note, in the error case I encountered, the playback
// didn't discard future frames and kept decoding since then, which causes
// playing extra a whole audio track again.
info(`wait until video reaches to the end within correct remaining time`);
await once(video, "ended");
checkPoint2 = new Date();
const diffInSeconds = Math.abs(checkPoint1 - checkPoint2) / 1000;
ok(diffInSeconds < 2,
`finished playing within ${diffInSeconds} without incorrectly playing any future frame`);