aTube Catcher is a fully functional media conversion tool which can convert your downloaded video files to many different formats included audio-only or different video formats. It is a free, but ad-supported management downloading application that's well-designed, easy-to-use and attractive.
Here are some screenshots to illustrate the features and user interface of this application:
Monkey's Audio
Shutter Encoder
StaxRip
Hybrid
XMedia Recode