Blu-ray vs. HD DVD: The Format Wars



Blu-ray Technology (continued)

The Disc

The disc itself is coated in a hard protective layer made of a clear polymer, providing the discs with superb scratch resistance. The user can even clean their BD discs with a tissue without a second thought. This protective layer technology came into use due to the fact that the original Blu-ray discs were extremely susceptible to damage unless in a caddy. This caddy was a deterrent in that it was not as appealing to manufacturers and distributors due to the extra cost, nor as familiar to users as the HD DVDs.

The BD-ROM discs support MPEG-2, MPEG-4 AVC High Profile and VC-1 video codecs, which allows Blu-ray discs store up to four hours of video per layer. For audio it supports PCM, Dolby Digital, Dolby Digital Plus, DTS, DTS-HD and Dolby Lossless formats. MPEG-2 TS has been incorporated to allow direct recording from HDTV broadcasts without picture quality loss as well. The ability of optical discs to randomly access means that it is possible to playback video whilst simultaneously recording.

BD-RE and BD-R will be backwards compatible to MPEG-2. New codecs will be introduced and supported as they evolve over time. The technology will also include Java cross platform software for interactive menus on the discs, as compared to the pre-rendered segments used on current DVDs. This may also incorporate network connectivity enabling updates via the internet of the Blu-ray technology. This would mean that you could add new content such as subtitles in different languages as needed. The Java version of the disc will be called BD-J.


Regional codes for the BDs will be different to DVDs; there are only going to be three regions. 1= US, Canada, Mexico, South America, Japan & East Asia (excluding China) 2= Europe & Africa 3= China, Russia, and all other countries.

BD+ is a technology that allows dynamically changing encryption security. It is the method in which the data on the BD is encoded to prevent copying of the media. By constantly changing, it means that cracking one BD does not result in having all discs being cracked, as was the case with DVDs using CSS technology and the release of DeCSS in 1999 which allowed all DVDs to be cracked.

Digital watermarking has also been incorporated into BDs. Digital watermarking is a way of including a hidden copyright notice within the media, thus preventing duplication or reproduction without authorization. AACS is also to be included and is a product of AACS LA. This type of protection will also be used on HD DVDs, but is not receiving good press, so is not the primary source of protection for BDs.

BDs will also finally incorporate HDCP, High-bandwidth Digital Content Protection. This is a licensed technology that allows only licensed players to display the media at full resolution. Any players that do not have HDCP will either display a smaller sample or nothing at all. A HDMI interface can be used as it does include HDCP encryption.


The baseline data transfer rate of the Blu-ray technology is currently 36Mbps. 2x speed prototypes are in development with the intention of going up to 8x in the future. The numerical aperture used, 0.85, allows higher speeds. It also means that BDs require less recording power and lower disc rotation speeds to achieve the same data transfer rates as DVDs and HD DVDs.

Many manufacturers are starting to produce Blu-ray products. They are incorporating them into stand-alone recorders, game consoles, laptops, and PCs. BDA is recommending that manufacturers produce BD drives that are capable of reading DVDs. As such, optical heads have been created that can read CDs, DVDs and BDs. Panasonic released the first drive to support this, the SW-5582, and Pioneer has announced their drive will be released during the first quarter this year. The PlayStation 3 will also incorporate a Blu-ray drive.

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