Content Protection Recordable Media
A lot of dvd drive manufacturers have decided to build this in their (pc) drives, so when a digital content provider (on storage media or broadcasts) switches this "tag" on, a CPRM supported drive doesn't see this disc, or won't copy on or to CPRM supported flash cards, and the same may also come into effect on ATA hard disks,
because it works along the ATA protocol, but this is not yet official.

btw. Standalone DVD players should play this content normal,
but i guess they doo transport the tag/signal, that will trigger build-in CPRM protection electronics in pc hardware.