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.
Security
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.
Applications
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.
