(In reply to James Le Cuirot from comment #7)
> And still a problem in 4.2.0-rc1. Is there nothing I can do to move this
> along? It's really irritating. I have tried my best to fix it myself but to
> no avail.

The only thing which came to my mind we haven't tried so far is if you are sure
that it works with the 3.17 release (with UVD acceleration) and not 3.18 you
could try to bisect the changes between the two.

But apart from that I unfortunately don't have any idea either.