The Blu-ray Disc Association (BDA) has announced that it has selected the Advanced Access Content System (AACS) as its protection scheme for next generation DVD media.

The anti-piracy measures include a watermarking and digital rights management update scheme to secure discs against copying.

By choosing AACS, the BDA matches the rival HD-DVD (backed by the DVD Forum), which has chosen the same system.

The BDA, made up of PC vendors and Hollywood film studios, is responsible for promoting Blu-Ray technology as the standard for next-generation high capacity optical discs.

But user interest remains guarded due to the fact that to view the discs requires the use of DVD players that are not yet available. HD-DVD discs, on the other hand, will work on existing players.

The watermarking scheme means that discs will be secured with a Rom Mark, a means of embedding a unique identifier on the disc that also prevents it being played on unlicensed players.

So-called 'BD+' technology will be used to update rights management schemes built into next generation players. AACS technology was originally expected in March but is now expected by year end.

HD-DVD players are expected to be available by the end of 2005 and recorders will be due in the first half of next year. Blu-ray expects both recorders and players to be out in the first half of next year.

In June the HD-DVD camp narrowed the gap between the two specifications by announcing plans for a 45GB triple layer disc, bringing it closer to the dual-layer 50GB Blu-ray disc under development.

Blu-ray technology is backed by companies including Sony, Apple, Dell, HP, Panasonic, Sharp and Samsung, together with studios including Disney, MGM and Fox, whereas the HD-DVD camp includes Paramount Pictures, Universal Studios and Toshiba.