Debian has one of the largest software repositories around but also has a very strict policy (which I respect) when it comes to legal stuff concerning free software or copyrights. I guess this is the reason why some multimedia software packages are missing. If you stick with Debian you have to install them manually, or - if you want the easy way - you could of course add some third party respositories or change for example to Ubuntu which doesn't seem to share Debian's concerns. As I'm running sidux (which is based on Debian Sid) I wanted to go for the manual installation (I don't like to add repositories other than Debian's). Debian comes with an MPlayer package but it lacks menconder. If you need menconder you'll have to install from sources. lame, transcode, xvid and dvd::rip are not part of Debian repositories at all, so we'll have to install them from sources, too. In this HOWTO I'll explain how this worked for me (running sidux on amd64). I guess it should be similar to Debian testing or even stable.