• Technical Background

CD and DVD discs have been one of the most popular optical memories. The information is stored in the pits of disc tracks and read out by the laser beam of the optical drive. Regarding the data density of discs, the capacity of DVD is much larger than CD. So the wave length of the laser light applied to DVD is shorter than that of CD. The pit of CD is 0.834μm and the track distance is 1.6μm while the pit of DVD is 0.4μm and the track distance is 0.74μm. The largest capacity of CD is about 650M while general DVD is 4.7G and 17G for DSDL. With the development of HD technology and the popularization of large size HD TV, the lack of HD optical products becomes the key and crucial issue. Therefore, the blue laser optical product is the milestone of the optical memory technology.

• CBHD Performance

China Blue High-definition Disc(CBHD) (thereinafter CHDA) is a cooperative organization voluntarily combined and established by the related organizations and manufacturing enterprises engaged in the development of optical memory technology. In efforts of all members in two years, CHDA has developed a new and advanced kind of products, called CBHD (China Blue High-definition DVD). ?????The diameter of CBHD is 12cm, the same as DVD while the capacity of single side is 30G. Why does CBHD have so strong capability? The reason is related to its usage of 405 nm blue-violet laser and NA which is revised from 0.6 to 0.65. Therefore, the length of pit which is used to record data can be decreased to 0.204μm and the distance between tracks is 0.4μm, so that the capacity of disc is enlarged greatly. CBHD player not only reserves the useful DVD function such as multi-audio, multi-subtitle and multi-angle, but also equips simple and practical navigation system based on DVD navigation so as to implement the user’s intension more efficiently. The new function of two displaying areas in any menu is added and the user can be aware of the summarized content of the item before the related button is activated. Moreover, some swift and lively music is played when a button is selected. The data transfer rate of CBHD player reaches about 36Mbps. The video codec streams include AVS, MPEG2, H.264, VC-1, etc. and audio streams involve AVS audio, DRA, Dolby AC-3 and so on.?

• CBHD Format

CBHD Format Specifications includes three parts: physical format, file system and application format. Physical part specifies the structure of physical media. File system describes the recording method of logical data and other data structure. Application format is the regarding specifications of navigation, audio & video compression format and digital content protection. CBHD Specifications will keep updating from time to time according to the latest development situation.　Advanced audio/video compression technology is applied to CBHD products. For CBHD player, most advanced video streams such as AVS, MPEG-4 AVC and VC-1 are mandatory. The compression efficiency of them is twice higher than that of MPEG-2. As for navigation system, some brand new function such as two high-light area in a menu, which provides the summarized content before users active the button. Meanwhile, users can enjoy swift and lively music when buttons are activated. Regarding the content protection, considering the requirement of international content providers and the cost of manufacturing CBHD disc, CHDA developed a new technology named DKAA for content management. For domestic movies, DKAA will used while AASC is implemented for international movies.
The following table is showed the comparison among CBHD, DVD and BD.

• Industry Chain of CBHD

From technology aspect, CHDA self-developed advanced modulation for physical format, navigation system. Moreover, CBHD specifies related Chinese self-developed technologies, such as AVS video & audio and DRA as the mandatory items. Therefore, Chinese manufacturers can struggle for more right for IP issue. ????Meanwhile, CBHD disc can be compatible with DVD disc in physical format so that they can share production lines. It is well known that China is the country with the largest yield of DVD discs. Chinese manufacturers produce around ten billions DVD optical discs every year, which is about 30% of global yield. In conclusion, China has a powerful foundation of manufacturing red laser optical discs. For the compatibility of DVD discs and CBHD discs, the DVD production lines shall be revised a little so as to be capable to produce CBHD discs. It will shorten the development period and save the cost. Therefore, CBHD meets the requirement of Chinese industry, the market of HD products and the sustainable development of Chinese optical disc industry.
Meanwhile, content providers strongly support CHDA and contribute to CBHD products industry chain. Several content providers are SC members and/or founders of CHDA and they become the essential foundation and sustainment.
From all above, we believe there surely will be good future for CBHD. Let’s looking forward to the prosper of CBHD.