If you have uncompressed the codecs inside that folder, get the source version. It's pretty simple to compile (without gui) and at least in the distributions I've tried, using source for mplayer gives a much better performance.
1 - Get this file:
http://www1.mplayerhq.hu/MPlayer/rel....0pre5.tar.bz2
2 - Uncompress it:
bunzip2 MPlayer-1.0pre5.tar.bz2
tar xvf MPlayer-1.0pre5.tar
3 - Go into the uncompressed folder and compile it:
./configure
make
su root
make install
This would compile wiith all distributions if you have gcc and make installed. Otherwise, it will tell you to install those packages... Should take you 2 minutes to install them through YaST.
Please note that this will compile without gui support. Check the documentation to enable gui and other features (as joystick support). Compiling with gui has a lot of dependecies, but it's very simple: whatever packages are missing when you run a "./configure", install with YaST.
RPM's are good, but some applications are easier (and better) to install from source. MPlayer is the best example I know, plus it compiles easily and it's good practice. Don't be afraid of compiling fom source, it's really that simple
Good luck!