Convert .rmvb to .mp4

[NoobixCube]

I've found a lot of programs that convert practically any media type into any other (they're all frontends for FFMpeg), but none of them seem to support .rmvb files. The best program I've found, by far, is thinliquidfilm, because it's specifically tailored for the iPod, and with one click takes care of the resolution and bitrate. I'm just wondering, does anyone know of a good program for Linux, or one that will work in wine, for converting .rmvb files? It would be a huge help to me, since I bought an 80GB iPod for a reason, but I can't convert any of my anime at the moment

[Husse]

I don't know much about this file type, but it's a new Real media file type
This link seems to have info on how to get it working
http://www.simplehelp.net/2007/07/27/ho ... in-ubuntu/

[NoobixCube]

Oh, playing the files is no problem. In MPlayer, I just selected X11 OpenGL in the Video tab of the preferences, and they work flawlessly (X11 OpenGL 2 doesn't, for some reason). I just need to know how to convert them to work on an iPod.