advanced optical disc (advanced optical disc; The HD DVD specification of AOD is designed based on the current standard DVD specification. HD DVD completely inherits the same thickness of standard DVD data layer, but it adopts blue laser technology to the letter, but it has a short wavelength and can store dense data on the disc. Compared with the current standard DVD single-layer capacity of 4.7GB, the single-layer capacity of HD DVD is 15GB, which is a high-capacity optical storage technology.
the main selling point of HD DVD specification is that HD DVD and standard DVD*** share part of the structural design. DVD manufacturers should not invest huge sums of money to update their production equipment for the specification upgrade. Blu-ray manufacturers must purchase brand-new production equipment for the production of new specifications.
HD DVD specification also continues the data structure of standard DVD (such as architecture, index and ECC blocks). Error proofreading algorithm comes from the module structure of standard DVD, and the only difference from standard DVD is ECC blocks used to receive more error proofreading. Error proofreading of ECC blocks is continuous. In HD DVD, one ECC block is equal to two linked ECC blocks in standard DVD.
in April, 25, HD DVD will adopt advanced access content system (AACS), a higher-level version of CSS, which has already been applied to the standard DVD specification and won a good evaluation. The Patent Affairs Committee Association is composed of IBM, Matsushita Electric Industrial, Microsoft, Toshiba and Sony members. Because Disney is a member of BD camp, so is Warner.
Dan Ramer published a worrying report article in the newspaper, which mentioned the name Independent Security Evaluators；; ISE) examined AACS and SPDC (self-protecting digital content) two anti-theft copying systems. SPDC has already appeared in HD DVD security system, and it has been recognized by the association as superior to AACS.
during the production of DVD players, AACS will give each machine a set of 128-bit Device Keys, which can be used in a single device or shared with other multi-task devices. MKB (Media Key Block) is an anti-theft code legally authorized by AACS. This set of anti-theft codes can be decoded and restored. If the anti-theft code is damaged, MKB will immediately regenerate and destroy the original anti-theft code to protect itself, so the anti-theft code cannot be restored.
this kind of design is heart-pounding, because if the anti-theft code of DVD player is damaged and detected, unless the ROM read-only firmware is upgraded, the DVD player will be locked and unable to start to avoid being copied, so it will make people hesitate to use it. AACS has built-in internet access function, which can link the CRM customer service management or content manipulation management of the website. Therefore, online connection is inevitable in the future.
SPDC has a mechanism to restore the DVD player, play back all the contents of DVD discs, and also record the restored recorded contents. Because the DVD player has a video recording function, if a DVD is damaged after being placed in the DVD player, then your DVD player will become a security door bolt and start the self-protection and anti-lock anti-theft function.
in fact, the function of secret monitoring in the system is not limited to this. Even when a DVD player plays a new disc every time, the SPDC self-protection and anti-lock mechanism is started immediately. Therefore, when the old CD is damaged, each new CD seems to be an informer, who will come forward to confess and record the truth on the RAM that can be kept forever and can correct the firmware of the player.
the playing software named Divx is not compatible with SPDC, and Divx is just one of many incompatible softwares. If there are more incompatible softwares, it may lead to the supporters of the original standard DVD specification and produce the psychology of rejecting the HD DVD specification.
HD stands for both high density (the storage capacity of the disc is larger) and high resolution (the picture with better quality). The first commercial Blu-ray HD DVD came out in Japan in April this year. These DVDs can only be used for home recording, not for pre-made HD movies, and can only be used under the digital HD broadcasting system in Japan.
the new DVD format will not replace the existing DVD format soon, but the new HD player can play the existing DVD movies and make the picture look better with progressive scanning technology. But the new HD DVD disc can't be played on the existing DVD player. The DVD movies we have now can be played for many years. Think about it. In the United States, the HDTV system was expected to be available in 1989, but it was still not finalized in 1996 and did not go to the market in 1998. Can HDTV eliminate existing TVs so quickly?