MP3 Rocket

MP3 Rocket is a big freeware for people interested
in more than just converting youtube video files.
You can search and download videos directly from
the program, download MP3's, it also has a built in
player and many more features. The download speed
is limited and slow on the free version but acceptable.
Overall this is a nice freeware, it is more a multimedia
program than a simple converter.

Suported audio format:

Publisher Website