Yes it is...
This problem is also happening on Windows 7... I don't know what happened to recent ATI drivers, but this card in the decoded H264 and VC-1 videos properly on Windows Vista / Windows 7 before. Now, it doesn't (in both Windows and linux Catalyst drivers...).
With relative recent versions of xvba-video and Catalyst Linux 10.x (between Catalyst 10.4 and Catalyst 10.7), we could decode videos properly with a UVD1 card. Now (with catalyst 10.8-10.12), nothing.
Cheers
p.s.: Btw, UVD2 cards (HD4xxx and higher) seem to work properly with recent Catalysts... (Tested on my desktop's HD4650, with Catalyst 10.12)