An anonymous optical disc R&D engineer wrote to me with news of CinemaNow's "Burn to DVD" system. This is the system that lets you burn a DVD from your downloaded CinemaNow Windows DRM videos.
The engineer recently reviewed the "Burn to DVD" specification and found that the system has been designed really badly — so badly that it's likely that DVDs burned with CinemaNow are likely to fail in many commercial DVD players.
The system is based on the deliberate introduction of errors caused by Digital Sum Value (DSV), a sum that represents the ratio of land to pits on the surface of the DVD. The DVD spec notes the possibility of DSV errors and instructs implementers to take care to avoid them, as these errors can cause a host of problems with reading and playing discs.
My source notes that the introduction of DSV errors is indiscriminate and uncontrollable — the multitude of possible combinations of DVD burners' chip-sets, blank media, and other variables means that any attempt to introduce DSV errors will produce unpredictable outcomes.
The engineer tried burning Burn-to-DVD discs with a variety of test-bench equipment and found that many of his burners failed entirely, and of those that succeeded, many produced unplayable, error-ridden discs.
For the "successful," marginally playable discs, the news is still bad, since those discs will already be at the limit of their players' error-correction threshold, so that minor scratches and dust would render them useless.
My source also believes that this technique infringes on several patents, including this one.
My source sums it up neatly in this outraged paragraph: "I'm against people being fleeced by this kind of crap. How can you sell someone content on media that is so heavily compromised, especially on a format that so heavily relies upon its error correction system to maintain playability? It's mind boggling!"
(Thanks, anonymous engineer!)
Update: Tian sez, "Recently, my local news
crew has tested out the service and found it to be crap. I have also
wrote about the crappy service especially CinemaNow's Burn To DVD's
DRM. Even though my local news crew was able to burn one DVD
successfully, CinemaNow's "one copy only" DRM can be easily defeated."