In order to prevent multiple people from surreptitiously using its cheap digital movie conversion service to score cheap HD movies, Wal-Mart is using a special ink to mark discs that have already been converted (the ink doesn't affect disc playback). "Disc-to-Digital," which launches officially April 16th (Monday), allows owners of DVDs and Blu-ray discs to get digital copies of their films from Wal-Mart's UltraViolet-powered digital locker. The service costs $2 per disc to access a high-definition download or stream from a Blu-ray (or a standard-def one from a DVD), or $5 per disc to upgrade a DVD to HD. Disc-to-Digital incorporates Wal-Mart's Vudu front-end, allowing converted films to be accessed from mobile devices, gaming consoles, and Smart TVs.

For the service, Wal-Mart is partnering with five studios, including Fox, Paramount, Sony, Universal, and Warner Brothers, but that doesn't mean all of their films will be convertible — some actors and directors haven't agreed to sign over the rights to their films (George Lucas and the Star Wars movies, for example). While Disc-to-Digital is only launching with 4,000 films, the cheap price and prevalence of Vudu could finally give UltraViolet the push it needs to overcome its awkward start.