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+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>MSE: video resolution changes during playback should not cause video freeze (Bug 1718709)</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="mediasource.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<script class="testbody" type="text/javascript">
+
+SimpleTest.waitForExplicitFinish();
+
+runWithMSE(async (ms, v) => {
+  await once(ms, "sourceopen");
+  const sb = ms.addSourceBuffer('video/mp4');
+  sb.appendBuffer(new Uint8Array(await fetchWithXHR("bug1718709_low_res.mp4")));
+  ok(true, "appended low resolution video");
+  sb.appendBuffer(new Uint8Array(await fetchWithXHR("bug1718709_high_res.mp4")));
+  ok(true, "appended high resolution video");
+
+  info(`start from the position which is near to the place where resolution changes`);
+  v.currentTime = 13;
+  ok(await v.play().then(_=>true,_=>false), "video started playing");
+
+  // When video resolution changes, it should not cause video freeze so we check
+  // its painted frame amount regularly to see if we stop updating video frames.
+  let lastPaintedFramesAmount = v.mozPaintedFrames;
+  const intervalHandle = setInterval(_=>{
+    ok(lastPaintedFramesAmount < v.mozPaintedFrames,
+       `painted frames keeps growing from ${lastPaintedFramesAmount} to ${v.mozPaintedFrames}`);
+    lastPaintedFramesAmount = v.mozPaintedFrames;
+  }, 1000);
+
+  // As we didn't append full video, so we will receive `waiting` event later
+  // which indicates that we can stop testing because we've finished playing
+  // the high resolution part.
+  await new Promise(r => {
+    v.onwaiting = _ => {
+      clearInterval(intervalHandle);
+      r();
+    }
+  });
+  SimpleTest.finish();
+});
+
+</script>
+</body>
+</html>