beets

beets is a media library management system for obsessive music collectors. It catalogs your collection and automatically improves its metadata, then hands you a suite of command-line tools for manipulating and accessing your music.

Its tag corrector matches tracks against MusicBrainz, Discogs, and Beatport, or guesses from filenames and acoustic fingerprints. Plugins fetch album art, lyrics, genres, tempos, and ReplayGain levels, transcode audio, find duplicate or incomplete albums, clean up crufty tags, and let you browse and play your library in a web browser via HTML5 audio.

Because it is built as a library, you can write your own plugin in a little Python to make it do almost anything. It installs with pip and is packaged by several Linux distributions.