How do you know they are the 9.3 drivers?
Anyways they work great on my HD4850 1gb I have working 3d with compiz/emerald and fullscreen vlc works fine (tested quickly on 5 videos)
However I get some weird flickering when the mouse moves on the vlc window while its playing fullscreen or not. But it dissapears when the mouse dissapears, so it's not too annoying.
I think i'll keep this one till something better comes along!
display: :0.0 screen: 0
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: ATI Radeon HD 4800 Series
OpenGL version string: 2.1.8306 Release