I think this happens since bug 188645 was fixed. At EOS for a looping video the reported position and duration differ, so the media element doesn't seek back to the beginning...
Created attachment 353855 [details] Patch
Comment on attachment 353855 [details] Patch Patch is ok, but we should have a regression test for it.
(In reply to Xabier Rodríguez Calvar from comment #2) > Comment on attachment 353855 [details] > Patch > > Patch is ok, but we should have a regression test for it. Of course it should... But due to the inconsistent (flaky) nature of the issue, it's going to be hard to get one.
There's already a test BTW, marked flaky for a long time already, media/video-loop.html
(In reply to Philippe Normand from comment #4) > There's already a test BTW, marked flaky for a long time already, > media/video-loop.html Does it pass now reliably?
Even before the patch it passes reliably here.
(In reply to Philippe Normand from comment #6) > Even before the patch it passes reliably here. This is even weirder. This is an important feature that is broken, we should really find a way to test this and avoid regressions. Might be related to the video we are using?
*** This bug has been marked as a duplicate of bug 211182 ***