Convert m4v / flv files?

Hey guys, I bought a new camcorder, but unfortunately it doesn't produce its files in a format compatible with any other editing system other than the one that comes with the CD. You can export it, though, or upload it directly to YouTube. So, I need to find a program where I can convert either .m4v or .flv files. Please, don't try to be cool and say 'use Google', because I have, and every single one of them I tried are garbage, and they come out in horrible quality.

Thanks