I just pushed
discident-glib to GNOME git, a small library that uses
discident.com's service to guess the title of DVDs. They have a database of some 250k DVDs, though the database itself isn't open, and the API doesn't seem to allow submission.
Still a few FIXMEs to go through and API docs to write, and it should be ready to be integrated in your
favourite DVD ripper.
Drop me a line if you're interested in using it in your app.