I’ve been working the RealPlayer support for Gentoo, lately, which has always been a bit of a nag for me. One thing I just committed to the tree is a new ebuild for RealPlayer 10.0.8, which adds optional support for the gui. Basically, if you don’t use the X flag, it will only install the codecs.
Another thing is that MPlayer has a new set of codecs to download, just for amd64 users. Right now, they are nothing more than 64-bit RealPlayer codecs, but they might be adding some more later. That’s in the tree now as media-libs/amd64codecs. I bumped mplayer as well to use the ‘real’ flag again, which will pull that in for amd64.
Hopefully those two small fixes will help people having issues with the codecs. In some cases, you’ll still have to use mplayer-bin or the RealPlayer gui.