(In reply to comment #11)

> 
> From the fact that you mention probabilities, and video corruption affecting
> the screen outside the video itself, it kind of sounds like you're
> describing the latter of those, and not the former (i.e. this bug). I don't
> want these two similar-but-separate issues to end up getting confused in the
> minds of the developers or testers.

Yes, you're completely right, what I observe exactly matches the other bug 
https://bugs.freedesktop.org/show_bug.cgi?id=73457 The jpeg screenshot is very
clear about the problem. Thanks for the sample file BTW.