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Test Info: Warnings

<title>Seamless looping test : do not keep painting old video frames</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 is used to ensure that after seeking to EOS directly, video can
* display its frame sucessfully, not showing the incorrect frame which should
* be discarded during seeking. The test video contains three seconds white
* frames [0s-3s] and one second black frames [3s-4s], so after seeking to
* EOS and start looping video again, video should display white frames, instead
* of black frames.
add_task(async function testSeamlessLoopingDoNotKeepPaintingOldVideoFrame() {
info(`create video and play it`);
const WIDTH = 10, HEIGHT = 10;
let video = document.createElement('video');
video.loop = true;
video.src = "white-3s-black-1s.webm";
video.width = WIDTH;
video.height = HEIGHT;
info(`seek to EOS (${video.duration}s) and waiting for looping`);
video.currentTime = video.duration;
await once(video, "seeked");
// We can't control the exact timing when the compositor would render next
// frame so we wait for the next timeupdate to ensure the media has been
// moved forward to the place where video should show white frames.
info(`wait for timeupdate then check the painted frame`);
await once(video, "timeupdate");
const canvas = document.createElement('canvas');
const context = canvas.getContext('2d');
canvas.width = WIDTH;
canvas.height = HEIGHT;
context.drawImage(video, 0, 0, canvas.width, canvas.height);
const pixelData = context.getImageData(0, 0, WIDTH, HEIGHT).data;
for (let idx = 0; idx < WIDTH * HEIGHT; idx++) {
let pixelCount = 4 * idx; // RGBA
// White frame's RGB value should be [255,255,255]
is(pixelData[pixelCount + 0], 255, `R should be 255`);
is(pixelData[pixelCount + 1], 255, `G should be 255`);
is(pixelData[pixelCount + 2], 255, `B should be 255`);