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.