Blue ray disc

Contents of the paper

 Introduction
 Structure
 Storage
 Construction
 Reading Issues
 File System
 Technological Aid
 Pros & Cons
 Conclusion

ABSTRACT:

The thrust for an advanced limitations of the DVD
format of data storage on format & begun working on
optical disc led to BD even before DVD's
revolutionary introduction of release.
BLU-RAY DISC. This
advances in the race against its Blu ray disc is the
competitors DVD (Digital next generation digital video
Video Disc) & AOD disc. It has an edge over the
(Advanced Optical Disc) in traditional dvd's & lesser used
that it has high storage cd's that it has more storage
capacity, advanced security capacity with the size of the
and privacy features and the disc being constant. Also we'll
A/V high quality O/P discuss now the other features
(generally video) of the media of this disc which makes it
files stored on it make’s it quite unique & gives it a
quite unique & gives an edge chance to be well adapted in
over the others, letting BD to all sorts of applications
be widely adaptable in every everywhere.
application possible.
This paper essentially
Suprisingly, the is confined with the structure,
necessity for a next generation construction, reading issues &
disc had begun in 1994 even advantages of the Blu-Ray
before the advent of the DVD Disc. To be effective, at every
in the market in 1996. The stage the disc is compared
then scientists predicted the with DVD.

INTRODUCTION:
BD --> Blu-Ray Disc

The founding stones for the very tight challenges. Here are
Blu Ray Disc technology were some reasons why there’s
laid in 2002 by the Blu Ray been a rush to change from the
Disc Association (BDA) in an current format of DVD:
attempt to overcome the
drawbacks in DVD's. This SIZE : A single-sided,
attempt has almost reached the standard DVD can hold 4.7
zenith & the world now is GB (gigabytes) of
shortly about to use a disc of information. That's
an incredible storage capacity about the size of an average
& with almost all the apex two-hour, standard-definition
features incorporated, that movie with a few extra
ensures user security and features. But a high-definition
privacy and enables one to movie, which has a much
operate the disc in the most clearer image, takes up about
efficient and convenient way five times more bandwidth
ever imagined. and therefore requires a disc
with about five times more
WHY BD? storage. As TV sets and movie
Early in 1997, a studios make the move to high
new technology emerged that definition, consumers are
brought digital sound and going to need playback
video into homes all over the systems with a lot more
world almost thrashing out the storage capacity, which a
then conventional CD's. It was DVD cannot support. Also,
called DVD, and it more space on a single disc
revolutionized the movie invariably results in higher
industry. This format ruled the disc size. This bulky size of
market for over a span of 5 the disc is neither convincing
years, but now is facing some nor convenient.

SECURITY : CSS is toast, noticeable. The quality of the
thanks to some smart video o/p of the media files on
programmers in Europe and a DVD or a CD is not up to
some foolish programmers at the mark.
the now-defunct Xing SOLUTION :The industry is
Technologies. The group that set for yet another revolution
created the DeCSS software with the introduction of Blu-
figured out how to break the ray Discs (BD). With their
encryption by reverse high storage capacity, Blu-ray
engineering Xing's DVD discs can hold and playback
decryption key, which wasn't large quantities of high-
properly protected. The end definition video and audio, as
result is that DVDs can be well as photos, data and other
copied as easily as music CDs. digital content. Also
The market hates the fact that incorporated are some
the DVD format is now advanced security and privacy
vulnerable and there's nothing options and convenient
they can do about it, and are accessibility features.
eager for a new format that is
much more secure. A single sided
blu ray disc has the capacity to
QUALITY : The final reason store information of about 27
for the change is video gigabytes, that’s about the size
quality. DVD video is of 13 hr standard definition
presented in 480p, or 480 lines movie or more than 2.5 hrs of
per screen, progressive a high definition movie. While
scanned video. High the double layered one can
Definition TV (HDTV) is store to about 54 gigabytes.
presented in 720p or 1080i. This enormous storage
You won't notice any capability is considered to be
difference without a high the major plus point of the blu
definition television, but if ray disc to that of the
you do have an HDTV set, the conventional DVD’s in the
improvement in quality is very market right now.

STRUCTURE:
The structure of the Blu-Ray
disc is shown as below. It
differs from the traditional
DVD that, in a DVD the data
is sandwiched between two
0.6mm polycarbonate layers.
While in the case of a BD the
data layer is placed on a
1.1mm polycarbonate layer.
To prevent the data on the top
of the disc from getting
erased, the data layer is
covered by a 0.1 mm from the centre of the disc to
protection layer. This makes the end of the diameter of the
the size of all the CD's DVD's disc. This spiral starting from
& the BD's constant. This the centre of the disc gives the
packing of the data has many flexibility for the disc to be
advantages which will be smaller in size than that of the
discussed in the later sections. conventional 120 mm. On this
spiral tracks exists the
STORAGE: BUMPS which actually hold
It should be noticed that the data. These bumps lie all
whatever form of the disc may along the spiral track. These
be under consideration the bumps are often called pits.
data on the disc is stored on a Viewed from the top of the
SPIRAL TRACK running disc these bumps look like
PITS.

CONSTRUCTION:
The construction of the bumps small as that of the DVD
(spiral track) is explained here which is 0.74 microns. This
from a closer view of the disc. small pit & reduced track
The view is so close that the pitch enables the
bumps can be seen clearly. accommodation of a data of
Here each white hole about 25 gb on a single sided
represents a bump (pit). For Blu-Ray disc which is almost
clear understanding it is 5 times that of a single sided
effectively compared with a
DVD.
The key terms used here are:
• Pit Length: It is the
length of the pit on the
spiral track which holds
the data.
• Track Pitch: It is the
distance between any
two successive tracks.
From the figure above :
The minimum pit
length of a BD is 0.15 microns
which is more than twice as
small as the pits on the DVD traditional DVD.
which is at minimum 0.4
microns. Also the track pitch
of the BD is 0.32 microns
which is more than twice as

READING ISSUES

The till now regularly used therefore not exactly
DVD's & VCD's face two perpendicular to the beam
basic problems regarding their (laser), it can lead to a
physical structure. They are: problem known as disc tilt, in
• Birefringence. which the laser beam is
• Disk tilt. distorted. This sometimes may
lead to reading or writing into
Birefringence: In a DVD, the other undesired memory
data is sandwiched between locations.
two polycarbonate layers,
each 0.6-mm thick. Having a SOLUTION: The Blu-ray
polycarbonate layer on top of disc overcomes DVD-reading
the data can cause a problem issues by placing the data on
called birefringence, in which top of a 1.1-mm-thick
the substrate layer refracts the polycarbonate layer. Having
laser light into two separate the data on top prevents
beams. If the beam is split too birefringence and therefore
widely, the disc cannot be prevents readability problems.
read. And, with the recording layer
sitting closer to the objective
Disk Tilt: If the DVD surface lens of the reading
is not exactly flat, and is mechanism, the problem of
disc tilt is virtually eliminated.

FILE SYSTEM

The file system here has two help during the system scan &
important aspects of others.
consideration: There exists different
• Data arrangement. file systems (derivative of the
• Data retrieval. general one)for different
versions of the BD that are
DATA ARRANGEMENT: BD-ROM , BD-Rewritable ,
The general file system used BD-Recordable.
in Blu -Ray disc is quite Blu-ray Rewritable
unique. It divides entire disk discs are non-sequential
space into two parts. recording media, where read-
• Metadata & Database modify-write and defect
area management operations are
• Real time Recordable performed by drive unit,
area eliminating the need for the
The real time recordable Virtual Allocation Table and
area is the major part in Sparing Table in the file
respect to size on the disc & it system.
contains the real time files Blu-ray Recordable
used by the user. They vary discs also include defect
from a/v streams to s/w management, eliminating the
programs to documents. While need for the Sparing Table
the Metadata & Database area inthe file system. The defect
holds the information that management system allows
manages the data in the real for the replacement of
time recordable area. . This defective clusters as well as
MD files actually serves as a enabling the logical
means of quick access to the overwriting of previously
folders & enable the users to recorded user data. For Blu-
open (operate) multiple ray Read-Only discs, the
directories at the same time & requirements are simplified
since there is no need for read-

modify-write, overwriting or When a single Real-Time
incremental recording of user file is made up of several
data. expanses, the file is read by
jumping from one expanse to
the next and reading the
expanses in order. However,
when jumping from one
expanse to another, the disc
rotation speed needs to be
changed and the optical
pickup needs to be moved to a
2) DATA RETRIEVAL different radius on the disc.
(CONTINUOUS): Although data cannot be
When retrieved from the disc during
recording, deleting or editing this interval, the
operations are performed decoding/playback of
repeatedly, small areas of video/audio data must
empty space will occur across continue without interruption.
the disc. These small areas can To prevent interruption
be used to record a new Real- in video/audio playback while
Time file, which results in a reading data from the disc, the
single Real-Time file buffer memory must not be
composed of many small emptied of data before readout
extents scattered across the from the next expanse
disc. A group of these extents, becomes possible. This
each of which is recorded on requirement for continuous
contiguous logical sectors, is supply of data is necessary to
called an Expanse. The insure seamless playback.
Expanse is conceptually a Therefore the minimum
contiguous area to be read, expanse size is defined such
and may include small areas in that the buffer memory does
which Real-Time data is not not become empty when
recorded. jumping from one expanse to
another on the disc.

TECHNOLOGICAL AID
• Laser and optics physically contained in the
Blu-ray systems use a same area.
"blue" (technically blue-
violet) laser operating at a • Hard-coating
wavelength of 405 nm to read technology
and write data. Conventional
DVDs and CDs use red and Because the Blu-ray
infrared lasers at 650 nm and standard places data so close
780 nm respectively.The blue- to the surface of the disc, early
violet laser's shorter discs were susceptible to dust
wavelength makes it possible and scratches & fingerprints
to store more information on a and had to be enclosed in
12 cm CD/DVD sized disc. plastic caddies for protection.
The minimum "spot size" on Such an aggravation, the
which a laser can be focused consortium worried, would
is limited by diffraction, and hobble Blu-ray's adoption in
depends on the wavelength of the face of the rival HD DVD
the light and the numerical standard; HD DVDs can be
aperture of the lens used to handled bare (caddy less) like
focus it. By decreasing the CDs and DVDs, making them
wavelength, using a higher familiar to consumers as well
numerical aperture (0.85, as attractive to manufacturers
compared with 0.6 for DVD), and distributors who might be
higher quality, dual-lens deterred by additional costs.
system, and making the cover The solution to this
layer thinner to avoid problem arrived in January
unwanted optical effects, the 2004 with the introduction of
laser beam can be focused a clear polymer that gives Blu-
much more tightly at the disk ray discs unprecedented
surface. This produces a scratch resistance. The
smaller spot on the disc and coating, developed by TDK
allows more information to be Corporation under the name
"Durabis," allows BD’s to be

cleaned safely with only a extension BD-R) will by and
tissue—a procedure that can large support the MPEG2
damage CDs,DVDs, and codec. For users recording
(presumably) HD DVDs, digital television broadcasts,
which are manufactured by the Blu-ray's baseline data rate
the same process as these of 36Mbit will be more than
older optical media. Bare adequate to record high
BD’s with the coating are definition broadcasts. Support
reportedly able to withstand for new codec’s will evolve as
attack by a screwdriver. new codec’s are encapsulated
by broadcasters into their
• Codec’s MPEG2 transport streams and
The BD-ROM format consumer set top boxes
specifies at least three video capable of decoding them are
codec’s: MPEG-2, the rolled out.
standard used for DVDs; • Java Software
MPEG-4's H.264/AVC codec; Support
and VC-1, a codec based on At the 2005 Java One trade
Microsoft's Windows Media show, it was announced that
9. The first of these only Sun Microsystems' Java cross-
allows for about two hours of platform software
high-definition content on a environment would be
single-layer BD-ROM, but the included in all Blu-ray players
addition of the two more as a mandatory part of the
advanced codec’s allows up to standard. Java will be used to
four hours per layer. implement interactive menus
For audio, BD-ROM supports on Blu-ray discs, as opposed
linear (uncompressed) PCM, to the method used on DVD
Dolby Digital, Dolby Digital video discs, which uses pre-
Plus, DTS, DTS-HD, and rendered MPEG segments and
Dolby Lossless (a lossless selectable subtitle pictures and
compression format also is considerably more
known as MLP). primitive. Java creator James
In order to remain backwards Gosling, at the conference,
compatible, BD-RE (and by

suggested that the inclusion of • Security
a Java virtual machine as well Blu-ray has an experimental
as network connectivity in BD security feature titled BD+
devices will allow updates to that allows for dynamically
Blu-ray discs via the Internet, changing encryption schemes.
adding content such as Should the encryption be
additional subtitle languages compromised, manufacturers
and promotional features that can update the encryption
are not included on the disc at scheme and put it on all new
pressing time. This Java discs, preventing a single
Version will be called BD-J crack from opening up the
and will be a subset of the entire specification for the
GEM standard. duration of its lifetime. It also
uses the Mandatory Managed
• Compatibility Copy system allowing users to
While it is not compulsory for securely rip a file into a secure
manufacturers, the Blu-ray format, a feature originally
Disc Association recommends requested by HP.
that Blu-ray drives should be The lack of a dynamic
capable of reading DVDs, encryption model is what
ensuring backward made DeCSS so disastrous in
compatibility. the industry's eyes: once CSS
JVC has developed a three was cracked, all DVDs from
layer technology that allows then on were crack able.
putting both standard- Under the name "ROM-
definition DVD data and HD Mark," this technology will be
data on a BD/DVD combo built into all ROM-producing
disc. If successfully devices, and prevent content
commercialized, this would from being reproduced in the
enable the consumer to event that a watermark is
purchase a disc which could detected. Through licensing,
be played on current DVD the BDA believes that it can
players, and reveal its HD eliminate the possibility of
version when played on a new mass producing BD-ROMs
BD player. without authorization.

PROS :
 High disc space at almost same cost price
 Security
 Reverse compatibility
 High speed data transfer (36Mbps)
 Online modifications

CONS :
 High cost of the disc reader.
 Less data space than AOD (HD-DVD 30 Giga bytes.

CONCLUSION :
It would definitely take a considerable time for the
Blu-Ray disc to hit the market & completely takeovers the DVD
share hold. Because of the low level compatibility (BD readers
able to read both the DVD’s and the CD’s), the task might become
a little simpler. But, the high cost of the reader might hinder its
quick development. Anyways soon or later this mass storage
optical device is going to replace the DVD & let the user
experience a world high quality & disc space (Quality & Quantity
ensured) with high level of security and privacy ensured.

Blue ray disc

More Related Content

What's hot (20)

Similar to Blue ray disc (20)

Recently uploaded (20)

Blue ray disc