The database may be licensed in GPL. However software written to access the database require a different license. For example, Adaptec's Toast software used to have direct access to the CDDB database via cddb.com. However, Roxio's equivalent replacement of Toast were denied access because Roxio doesn't have the license.
I don't know the details of the issue, I am just a user who can no longer access the database via Toast. Someone who know the details may add the license issues in the article.
Now I workaround the problem via a two step process. I use the freeware NetCD? to get the track info onto my computer. Then Toast works okay because it reads the same datafile on disk as NetCD?.
- see http://www.freedb.org/sections.php?op=viewarticle&artid=2 -- maybe this will help to answer your question -- WojPob