So, if you bought a DVD licensed by Sony, can they now legally enter your house and take your DVD?
Or can Sony have some sort of DRM that prevents the DVD from playing when Sony loses the license agreement?
I’m just trying to reconcile how digital purchases can be subject to license terms changes, while a DVD apparently can’t be.
If there is ever a next successor to Blurays, for VR film or something, their DRM could be linked to a validation server. Once it’s always online what you describe becomes possible.
Currently Blurays and dvds are designed for offline playback, and are read only, so their licenses are always valid and perform no verification.
Physical players disconnected from the internet can still receive offline firmware updates included on the discs themselves. The moment you insert a new disc, it automatically executes BD+ code that in theory could patch the firmware to blacklist an arbitrary old disc that you own. This has never yet happened with a previously-legal disc, but then again for example Amazon has never deleted purchased copies of the 1984 book from customers’ kindles, until one day when it did.