Tested Christian's xbmc-test branch of mesa with Rainer's amd branch of xbmc
(doin' what i'm told ;-))

Well it's fixed *a* problem; just not the one this bug is reporting. :-} If you
watch the video I linked at the top of this bug, there's a second or so of
glitchiness covering the whole screen before the looping behaviour (but
otherwise good-looking video) plays.

That initial glitchiness is gone! But the loopiness that follows is still
there. Also, I just get a black screen for what seems about the duration of the
glitchiness before, while the audio plays. Actually the video should be fading
in quickly from black from the very start.