kid3.kde.org
Kid3 is an audio tagger for editing ID3v1.1, ID3v2.3 and ID3v2.4 tags across many audio formats, including MP3, FLAC, Ogg/Vorbis and MP4/AAC. It can edit tags of multiple files, generate tags from filenames and filenames from tags, and import album data from sources such as MusicBrainz and Discogs.