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BD+, ROM-Mark, Region Coding

Blu-ray’s final trump card over HD DVD is BD+ and region coding. Both Blu-ray and HD-DVD incorporate AACS for the core of the data encryption. Unsurprisingly, this has been broken. Although Sony has taken a lot of flak for their rootkits, the Blu-ray Disc Association has really beefed up security with BD+.

BD+ is pretty cool technology. Essentially, BD+ provides a mechanism for the Blu-ray disc to take control over the player. Once the Blu-ray player is under the control of the movie, three things can happen.

1. Transform code


2. Basic countermeasures


3. Advanced countermeasures

Right now, the data on a Blu-ray or HD-DVD AACS is encrypted. Break AACS and you get access to the raw MPEG-2, VC-1, or MPEG-4 AVC data. With BD+ you can encrypt the AACS-encrypted data with a second layer. This basically allows studios to use one-time pad style encryption, using a different key for each movie. This means you cannot create a “Blu-ray copy” utility – someone has to manually hack the virtual machine for each movie in the same way crackers have to crack software independently for each movie. Basic countermeasures include Xbox 360-like firmware checks and auto-authentication. Advanced countermeasures allow studios to program their own encryption algorithms (offering security by obfuscation, which works in this case because the goal is to make casual and commercial piracy annoying enough where it’s cheaper to buy the real thing).

ROM-Mark is a unique identifier on each commercially pressed disc that allows customs agents to identify where a pressed disc was manufactured. In theory, this will help curb commercial piracy and counterfeit production of copyrighted material. The goal is to make cracking this system financially costly to the point where.

Region coding is pretty annoying for any of us who enjoy import movies, but many studios continue to advocate for region coding. The idea is that for a big-budget movie, it will be possible to obtain more “investors” (producers), by preselling home video distribution rights to different companies in different regions of the world, creating an open market.

None of these features are designed for end-users, but they are designed to help. Are they perfect? No. But this gives Blu-ray the perceived advantage from a movie studio’s perspective, at least when it comes to preventing both commercial and casual piracy.

Does Paramount care about piracy?

Every studio cares about piracy. The problem is that HD-DVD and Blu-ray are still niche formats. To date, 3.7 million high definition discs have been sold. Even if I assumed that each studio made a $20 profit per disc, that’s only $74M total sales for all studios for an entire year. If the New York Times is correct and Paramount was offered a $150M deal to go HD-DVD, it’s a no-brainer decision.

Economics aside, Paramount’s CTO gave a lengthy interview with PC World on his reasons for choosing HD-DVD. Many of the comments are things we’ve already discussed: the players are more affordable, the specification standard is fixed with less concern for legacy issues, and the development costs are lower. At the moment, Paramount believes that 30GB should be enough for most movies and one of the driving factors is the ease of programming in HDi for interactivity over BD-Java. BD-Java requires someone who really understands object oriented programming; HDi just requires that someone be comfortable with a scripting language.

It’s cheaper to develop HD-DVD discs, the quality is still better than over-the-air 1080i ATSC HD broadcasts, and the reported $150M financial incentive (Paramount distributes Dreamworks movies for home formats) makes Paramount’s decision seem like the smart move.