Between all the ripping of my (legally) purchased DVDs and transcoding them to the proper format for my iPod I found out that most of the applications that I used have something in common (from Videora [free] to Mediacoder (open source). All these applications actually use FFMPEG under the hood: FFMPEG literally accepts many fileformats, open-sourced and runs on too many platforms (it’s highly portable, I guess). Trouble is, since it’s part of the other multi-platform media player (MPlayer) and, particularly, thanks to the legal minefield that is called transcoding, the binaries for FFMPEG are hard to find (well, you can’t miss it now!) (you can also fetch the sources and compile a binary yourself: you’d probably need to get the MingW compiler/environment).
Anyway, all videoconverter applications that I found had either crappy interfaces or they came with that ‘build-in’ Internet browser that allows the developer to push unneeded and unwanted ads to your desktop. So yeah, it shouldn’t be too hard to build your own fricking video converter. You only need to know and study FFMPEG’s commandline options after reading this (boring code after the fold).
Update: Slightly related: the BBC’s programming team released the very first version of their Dirac Video Compression codec.