Anyway... here are a couple that are supposed to be front ends for both the Video converters and audio converters together.
http://movieconvert.sourceforge.net/ This is a nice looking one. The originator says no more time for the project but could be really nice if adopted and made a somewhat Sabayon app with updates or something? I was unfortunately unable to get it to download from sourceforge.

http://www.thugsatbay.com/tab/?q=tab-vi ... er-encoder
This one also looked interesting? Maybe can include them both in next release...
Well would be user friendly I guess. Too bad couldn't test them out for you. The [email protected] one has code but didn't specify how to install it. No instructions...