Did the FOSS people crack it? My recollection is that a software player (made by Xing, no not the German LinkedIn copycat site) accidentally distributed their keys unencrypted: https://www.wired.com/1999/11/why-the-dvd-hack-was-a-cinch/

Then again, encryption of something that the self-contained software will need to be able to decrypt is probably just a small hindrance.