ID3
ID3 is one of the oldest ways of storing metadata in MP3 files, and is only intended for MP3 files. There are two major versions.
ID3v1
This is a very basic tagging format. It's limited to the following fields:
- Song title
- Artist
- Album
- Year
- Comment
- Genre
- Album track (ID3v1.1)
ID3v2
ID3v2 is much more complicated than version 1, and all fields can be defined freely. It also supports embedding pictures and other data. Usually, a rewrite of the file is neccessary each time you update an ID3v2 field.