The purpose of beets is to get your music collection right once and for all. It catalogs your collection, automatically improving its metadata as it goes. It then provides a bouquet of tools for manipulating and accessing your music.

Source: https://github.com/beetbox/beets

MusicBrainz is an open music encyclopedia that collects music metadata and makes it available to the public.

MusicBrainz aims to be:

1. The ultimate source of music information by allowing anyone to contribute and releasing the data under open licenses.
2. The universal lingua franca for music by providing a reliable and unambiguous form of music identification, enabling both people and machines to have meaningful conversations about music.