Ctag

Ctag is, as the name suggests, a tagging tool written in C. It's an alternative to Stag, which when I used it, broke if you looked it at funny, which is to say, it was incredibly unstable. What is tagging? Tagging the act of taking the metadata of a music file and modifying the music tags it has. This is because a lot of my music comes poorly tagged, or not tagged at all.

=> See the source code here