libdvdetect provides fast database lookup for DVDs
...The DVD Detection Library (libdvdetect) is a library to lookup DVDs in a database and provide information about e.g. title, UPC/EAN or even cover arts. It is OS-independent and compiles for Windows or Unix operating systems. Mac support is also planned.
What the library does not provide is DVD ripping and decryption. It reads the structure (e.g. titles and chapters) and generates a special checksum to look up the database.
More details at http://www.dvdetect.de. The database can also be searched using a web browser at http://search.dvdetect.de/.
For those who are curious I suggest downloading the binaries from https://sourceforge.net/projects/libdvdetect/files/binaries/ to try it out (windows only).