I discovered another problem with my mplayer installation, I can open any media file using mplayer but when i try to open the same file in gmplayer some media files don't work. It seems like mplayer has access to all of the audio files and gmplayer doesn't. For instance, I can open a movie clip in mplayer, and then when I open it in gmplayer I don't get any audio or it doesn't work at all.
and another question:
Is there any way I can search for packages that I don't need, to clean up my installation? Like searching for packages that don't have any dependencies?