MusicBrainz Picard is a cross-platform (Linux/Mac OS X/Windows)
application written in Python. It supports the majority of audio
file formats, uses PUID audio fingerprints, performs CD lookups
and disc ID submissions, and it has excellent Unicode support.
This application is the official MusicBrainz tagging application.

Note: You need to compile and install `chromaprint' with `ffmpeg'
installed for getting the `fpcalc' utility to lookup the music
files against `AcoustID' and `MusicBrainz'. In picard's settings,
point the "Fingerprint calculator" to /usr/bin/fpcalc