I am facing a few similar issues on the same hardware but this time here on LMDE 64-bit. Please visit http://forums.linuxmint.com/viewtopic.php?f=49&t=72645
Previously I had hd playback problem on Eee PC 1215b on Mint Katya. After installing catalyst drivers the issues were resolved and hd playback, especially 720 and 1080p playback of mkv, mov and avi files was smooth as silk.
But I opted to move to lmde and installed the latest 64-bit release. Followed the amd catalyst wiki and installed fglrx drivers. glrxinfo, glrxgears and fgl_gears show that catalyst is installed well. even, glrxgears throws 1600 fps. However, mplayer, totem and vlc, none can play hd videos, though anything below 720p plays quite nice. There's one more problem - the volume hotkeys are not working. but i can live with it.
I've attached the package list, , so that you can suggest me if i am missing any package. Please guide me.
Here are some other details: