Review on: Blu-ray Disc

BY:

K.Sirisha
Santh Samarth Engineering
College
siri_5505@yahoo.co.in

Abstract
The modern world of technology could not have
come about excet for the develoment of the
comuter. !any eole believe that storage is the
most imortant feature in a "C. #or these reasons
comuter storage systems have grown in caacity
and seed at about the same rate as rocessors.
Today$ otical systems are the most oular
alternatives to magnetic storage systems. The
most widely used otical systems are C%s and
%&%s.
'ecause of the continuing demand for greater
storage caacity$ hardware manufacturers are
always searching for alternative storage media.
This led to the introduction of 'lu(ray %isc)'%*.
The aim of this aer is to study the
advantages of the 'lu(ray %isc over the %&%s
and other otical systems.
+ith their high storage caacity$ 'lu(ray discs
can hold and lay bac, large -uantities of high(
definition video and audio$ as well as hotos$ data
and other digital content.
.n this aer$ a detailed comarison is made
between 'lu(ray %isc and %&%s based on their
wor,ing$ writing$ caacity$ comatibility and
other arameters.
Introduction

In 1997, a new technology emerged that brought
digital sound and video into homes all over the
world. It was called %&%, and it revolutionized the
movie industry. The industry is set for yet another
revolution with the introduction of lu!ray "iscs
#"$.. The format offers more than five times the
storage ca%acity of traditional "&"s and can hold
K.S%andana
Santh Samarth Engineering
College
Sandana_/01@yahoo.co.in
u% to '() on a single!layer disc and (*) on a
dual!layer disc.
The name lu!ray is derived from the
underlying technology, which utilizes a blue!violet
laser to read and write data.
The lu!ray "isc format was develo%ed by the
lu!ray "isc +ssociation #"+$, a grou% of
leading consumer electronics, %ersonal com%uter
and media manufacturers, with more than 1,*
member com%anies from all over the world. The
oard of "irectors currently consists of
+%%le -om%uter, Inc.
"ell Inc.
.itachi /td
/) 0lectronics Inc.,
Samsung 0lectronics /td
Sony -o /td etc.
+ current, single!sided, standard "&" can hold
1.7 ) #gigabytes$ of information. That2s about
the size of an average two!hour, standard!
definition movie with a few e3tra features. ut a
high!definition movie, which has a much clearer
image, ta4es u% about five times more bandwidth
and therefore re5uires a disc with about five times
more storage. +s T& sets and movie studios ma4e
the move to high definition, consumers are going
to need %laybac4 systems with a lot more storage
ca%acity.
lu!ray is the ne3t!generation digital video
disc. It can record, store and %lay bac4 high!
definition video and digital audio, as well as
com%uter data. The advantage to lu!ray is the
sheer amount of information it can hold6
+ single!layer lu!ray disc, which is roughly
the same size as a "&", can hold u% to '7 ) of
data !! that2s more than two hours of high!
definition video or about 17 hours of standard
video.
+ double!layer lu!ray disc can store u% to (*
), enough to hold about 1.( hours of high!
definition video or more than '* hours of standard
video. +nd there are even %lans in the wor4s to
develo% a disc with twice that amount of storage.
BD Formats

+s with conventional -"s and "&"s, lu!ray
%lans to %rovide a wide range of formats including
89:;8;8<. The following formats are %art of the
" s%ecifications6
"!89: #read!only$ ! for distribution of ."
movies, games, software, etc.
"!8 #recordable$! for ." video recording and
=- data storage.
"!8< #rewritable$! for ." video recording and
=- data storage.
There2s also %lans for a ";"&" hybrid format,
which combines lu!ray and "&" on the same
disc so that it can be %layed in both lu!ray
%layers and "&" %layers.
Blu-ray Vs DVD
The com%arisons can be made based on wor4ing ,
ca%acity, writing, com%atibility ,s%eed and other
%arameters.
Working and Writing
lu!ray discs not only
have more storage ca%acity
than traditional "&"s, but
they also offer a new level
of interactivity. >sers will
be able to connect to the
Internet and instantly
download subtitles and
other interactive movie
features.
"iscs store digitally encoded video and audio
information in %its !! s%iral grooves that run from
the center of the disc to its edges. + laser reads the
other side of these %its !! the bum%s !! to %lay the
movie or %rogram that is stored on the "&". The
more data that is contained on a disc, the smaller
and more closely %ac4ed the %its must be. The
smaller the %its #and therefore the bum%s$, the
more %recise the reading laser must be. >nli4e
current "&"s, which use a red laser to read and
write data, lu!ray uses a blue laser #which is
where the format gets its name$. + blue laser has a
shorter wavelength #1*( nanometers$ than a red
laser #?(* nanometers$. The smaller beam focuses
more %recisely, enabling it to read information
recorded in %its that are only *.1( microns #@m$ #1
micron A 1*
!?
meters$ long !! this is more than
twice as small as the %its on a "&". =lus, lu!ray
has reduced the trac4 %itch from *.71 microns to
*.7' microns. The smaller %its, smaller beam and
shorter trac4 %itches together enable a single!layer
lu!ray disc to hold more than '( ) of
information !! about five times the amount of
information that can be stored on a "&".

0ach lu!ray disc is about the same thic4ness #1.'
millimeters$ as a "&". ut the two ty%es of discs
store data differently. In a "&", the data is
sandwiched between two %olycarbonate layers,
each *.?!mm thic4. .aving a %olycarbonate layer
on to% of the data can cause a %roblem called
birefringence, in which the substrate layer refracts
the laser light into two se%arate beams. If the beam
is s%lit too widely, the disc cannot be read. +lso, if
the "&" surface is not e3actly flat, and is
therefore not e3actly %er%endicular to the beam, it
can lead to a %roblem 4nown as disc tilt, in which
the laser beam is distorted. +ll of these issues lead
to a very involved manufacturing %rocess.
The lu!ray disc overcomes "&"!reading
issues by %lacing the data on to% of a 1.1!mm!
thic4 %olycarbonate layer. .aving the data on to%
%revents birefringence and therefore %revents
readability %roblems. +nd, with the recording
layer sitting closer to the obBective lens of the
reading mechanism, the %roblem of disc tilt is
virtually eliminated. ecause the data is closer to
the surface, a hard coating is %laced on the outside
of the disc to %rotect it from scratches and
finger%rints.
a!acity
+ single!layer disc can hold '() and a dual!
layer disc can hold (*) data and over 9 hours of
high!definition #."$ video on a (*) disc and
about '7 hours of standard!definition #S"$ video
on a (*) disc can be fit.
To ensure that the lu!ray "isc format is easily
e3tendable #future!%roof$ it also includes su%%ort
for multi!layer discs, which should allow the
storage ca%acity to be increased to 1**)!'**)
#'() %er layer$ in the future sim%ly by adding
more layers to the discs. Sony has announced that
layering a disc beyond dual layering is %ossible,
allowing u% to a '**) ca%acity on a lu!8ay
disc with , layers.
om!atibility

ac4wards com%atibility with "&" was one of
the %rimary arguments ." "&" had against lu!
8ay, but as recent develo%ments have suggested,
that doesn2t really a%%ly anymore. In fact, Bust this
%ast wee4, we re%orted on the C";-" "ual
Dormat "isc,C which is a disc containing both lu!
8ay and -" data layers.
"!eed
lu!ray has a higher data transfer rate !! 7? :b%s
#megabits %er second$ !! than today2s "&"s,
which transfer at 1* :b%s. + lu!ray disc can
record '( ) of material in Bust over an hour and
a half. lu!ray also has the %otential for much
higher s%eeds, as a result of the larger numerical
a%erture #E+$ ado%ted by lu!ray "isc. The large
E+ value effectively means that lu!ray will
re5uire less recording %ower and lower disc
rotation s%eed than "&" and ."!"&" to achieve
the same data transfer rate. <hile the media itself
limited the recording s%eed in the %ast, the only
limiting factor for lu!ray is the ca%acity of the
hardware. If we assume a ma3imum disc rotation
s%eed of 1*,*** 8=:, then 1'3 at the outer
diameter should be %ossible #about 1**:b%s$.
This is why the lu!ray "isc +ssociation #"+$
already has %lans to raise the s%eed to ,3
#',,:b%s$ or more in the future.
ost
+s with any new technology the first generation of
%roducts will li4ely be 5uite e3%ensive due to low
%roduction volumes. .owever, this shouldn2t be a
%roblem for long as there is a wide range of lu!
ray related %roducts, %lanned, which should hel%
drive u% %roduction volumes and lower overall
%roduction costs. 9nce mass %roduction of
com%onents for lu!ray %roducts begins the %rices
are e3%ected to fall 5uic4ly.
+ccording to the lu!ray "isc +ssociation, the
overall cost of manufacturing lu!ray "isc media
will in the end be no more e3%ensive than
%roducing a "&". Traditional "&"s were built
by inBection molding the two *.?!mm discs
between which the recording layer is sandwiched.
The %rocess must be done very carefully to
%revent birefringence.
1. The two discs are molded.
'. The recording layer is added to one of the
discs.
7. The two discs are glued together.
lu!ray discs only do the inBection!molding
%rocess on a single 1.1!mm disc, which reduces
cost. That savings balances out the cost of adding
the %rotective layer, so the end %rice is no more
t#an t#e !rice o$ a regular DVD. The reduced
inBection molding costs offset the additional cost
of a%%lying the cover layer and low cost hard!coat,
while the techni5ues used for a%%lying the
recording layer remain the same. +s %roduction
volumes increase the %roduction costs should fall
and eventually be com%arable to "&"s.
%eed to u!grade
The %roblem with today2s "&"s is that they only
su%%ort S" and don2t have the necessary storage
ca%acity to satisfy the needs of .". That2s where
lu!ray comes in, it offers u% to (*) of storage
ca%acity and enables %laybac4, recording and
rewriting of ." in all of the ." resolutions
including 1*,*%. The format also su%%orts high!
definition audio formats and lossless audio.
In addition to the greater video and audio
5uality, the e3tra storage ca%acity also means there
will be %lenty of room for additional content and
s%ecial features. This combined with the new "!F
interactivity layer ado%ted by lu!ray will bring
the menus, gra%hics and s%ecial features to a
whole new level.
Di$$erences between Blu-ray and DVD

&arameters
Blu-ray DVD
Storage ca%acity '()
#single!layer$
(*) #dual!
layer$
1.7)
#single!
layer$
,.()
#dual!layer$
/aser wavelength 1*(nm #blue
laser$
?(*nm #red
laser$
Eumerical
a%erture #E+$
*.,( *.?*
"isc diameter
"isc thic4ness
1'*mm
1.'mm
1'*mm
1.'mm
=rotection layer
.ard coating
*.1mm
Ges
*.?mm
Eo
Trac4 %itch *.7'H@m *.71H@m
"ata transfer rate
#data$
"ata transfer rate
#video;audio$
7?.*:b%s
#13$
(1.*:b%s
#1.(3$
11.*,:b%s
#13$
1*.*,:b%s
#I13$
Blu-ray Vs 'D-DVD
The other big %layer is ."!"&", also called
A(D #+dvanced 9%tical "isc$, which was
develo%ed by electronics giants Toshiba and E0-.
."!"&" was actually in the wor4s before regular
"&", but it didn2t begin real develo%ment until
'**7.
+lthough lu!ray and ."!"&" are similar in
many as%ects, still they differ in6
a!acity: lu!ray utilizes a lens with a
greater numerical a%erture #E+$ than ."!"&",
the laser s%ot can be focused with greater %recision
to fit more data on the same size disc. This allows
lu!ray to hold '() %er layer #(*) on a dual!
layer disc$, whereas ."!"&" can only hold
1() %er layer #7*) on a dual!layer disc$. lu!
ray has also ado%ted a higher data transfer rate for
video and audio #(1:b%s vs 7?.((:b%s$. The
greater ca%acity and data transfer rates for lu!ray
will allow the movie studios to release their
movies with higher 5uality video and audio than
the ."!"&" format.
ontent: The lu!ray format has received
broad su%%ort from the maBor movie studios as a
successor to today2s "&" format. Seven of the
eight maBor movie studios #<arner, =aramount,
Do3, "isney, Sony, :): and /ionsgate$ have
already announced titles for lu!ray, whereas ."!
"&" only has su%%ort from three maBor movie
studios #<arner, =aramount and >niversal$.
'ardware su!!ort6 The lu!ray format has
broad su%%ort from the world2s leading consumer
electronics, %ersonal com%uter and media
manufacturers, including Sony, =anasonic, =hili%s,
Samsung, =ioneer, Shar%, F&-, .itachi,
:itsubishi, T"K, Thomson, /), +%%le, .= and
"ell. The lu!ray format will also be su%%orted in
the ne3t!generation =layStation 7 #=S7$ video
game console. This means that we will have a lot
of choice when it comes to %layers and hardware.
The ."!"&" format has far less su%%orters, so
the amount of %layers and hardware will be very
limited. -urrently, Toshiba is the only com%any
offering a stand!alone ."!"&" %layer.
Di$$erences between BD and 'D-DVD
&arameters
Blu-ray 'D-DVD
Storage ca%acity '()
#single!
layer$
(*) #dual!
layer$
1()
#single!layer$
7*) #dual!
layer$
/aser wavelength 1*(nm #blue 1*(nm #blue
laser$ laser$
Eumerical
a%erture #E+$
*.,( *.?(
"isc diameter
"isc thic4ness
1'*mm
1.'mm
1'*mm
1.'mm
=rotection layer
.ard coating
*.1mm
Ges
*.?mm
Eo
Trac4 %itch *.7'H@m *.1*H@m
"ata transfer rate
#data$
"ata transfer rate
#video;audio$
7?.*:b%s
#13$
(1.*:b%s
#1.(3$
7?.((:b%s
#13$
7?.((:b%s
#13$
(t#er com!etitors
lu!ray and ."!"&" are the two maBor
com%etitors in the mar4et, but there are other
contenders, as well. <arner ros. =ictures has
develo%ed its own system, called ."!"&"!9.
This system uses a higher com%ression rate to %ut
more information #about two hours of high!
definition video$ on a standard "&". Taiwan has
created the Dorward &ersatile "isc #D&"$, an
u%graded version of today2s "&"s that allows for
more data storage ca%acity #(.1 ) on a single!
sided disc and 9., ) on a double!sided disc$.
+nd -hina has introduced the 0nhanced &ideo
"isc #0&"$, another high!definition video disc.
There are also %rofessional versions of the blue
laser technology. Sony has develo%ed J"-+:
and =ro"ata #=rofessional "isc for "ata$. The
former is designed for use by broadcasters and +&
studios. The latter is %rimarily for commercial data
storage #for e3am%le, bac4ing u% servers$
It seems that the future holds a whole lot more
than '( to (1 ) on a single disc. =ioneer is
develo%ing an o%tical disc that will blow away the
hard disc in most of our =-s in terms storage
ca%acity, holding (** ) of data. .ow soK
=ioneer2s lasers are ultraviolet, which have an even
shorter wavelength than the blue
Re!lacements
+s &-8s don2t su%%ort recording of ."T&
%rogramming consumers will soon need to re%lace
them. lu!ray recorders combined with hard
drives offer a very fle3ible alternative for those
that want to record ."T&. <hile ."!"&8s
already allow consumers to record ."T&, the
amount of ."T& %rogramming that can be
recorded and archived is limited by the size of the
hard drive. lu!ray recorders will offer a solution
to this %roblem as they allow consumers to record
the video to lu!ray discs and then free u% the
hard drive. This should ma4e them %o%ular among
%eo%le that want to archive a lot of their ."T&
recordings. The lu!ray recorders will also offer a
lot of com%elling new features not %ossible with a
traditional &-86
L 8andom access ! instantly Bum% to any %lace on
the disc
L Searching! 5uic4ly browse and %review
recorded %rograms in real!time
L -reate %laylists ! change the order of recorded
%rograms and edit recorded video
L Simultaneous recording and %laybac4 of video
#enables Time sli%;-hasing %laybac4$
L +utomatically find an em%ty s%ace to avoid
recording over %rograms
L Im%roved %icture ! ability to record high!
definition television #."T&$
L Im%roved sound ! ability to record surround
sound #"olby "igital, "TS, etc$
There are %lans for "!89: #read!only$, "!
8 #recordable$ and "!80 #rewritable$ drives for
=-s, and with the su%%ort of the worldMs two
largest =- manufacturers, .= and "ell, it2s very
li4ely that the technology will be ado%ted as the
ne3t!generation o%tical disc format for =- data
storage.
Availability in t#e market

lu!ray recorders have been available in Fa%an for
some time, where more consumers have access to
."T& than in the >nited States. 9utside of Fa%an,
however, it has been a bit of a waiting game. The
lu!ray disc %layers became available for %urchase
in Fune '**?. The =layStation 7 is also lu!ray
com%atible, and movies are available in the
format. Fust as with most new technologies, lu!
ray e5ui%ment will be %ricey at first. In '**7,
Sony released its first lu!ray recorder in Fa%an
with a %rice tag of around N7,***. 9f course,
%rices will dro% as the format gains %o%ularity.
0ven when the new video standard begins to
re%lace current technologies, consumers won2t
have to throw away their "&"s, but they will need
to invest in a new %layer. The industry is %lanning
to mar4et bac4ward!com%atible drives with both
blue and red lasers, which will be able to %lay
traditional "&"s and -"s as well as lu!ray
discs.
Blu-ray advantages
record high!definition television #."T&$
without any 5uality loss
instantly s4i% to any s%ot on the disc
record one %rogram while watching
another on the disc
create %laylists
edit or reorder %rograms recorded on the
disc
automatically search for an em%ty s%ace
on the disc to avoid recording over a
%rogram
access the <eb to download subtitles and
other e3tra features
The develo%ment of new low cost hard!
coating technologies has made the
cartridge obsolete so a lu!ray doesnMt
need a cartridge instead it rely on hard!
coating for %rotection, which when
a%%lied will ma4e the discs even more
resistant to scratches and finger%rints
than today2s "&"s, while still %reserving
the same loo4 and feel. lu!ray also
ado%ts a new error correction system
which is more robust and efficient than
the one used for "&"s. In addition to this
we donMt need an internet connection for
basic %laybac4 of blu!ray of blu!ray
movies. The Internet connection will only
be needed for value!added features such
as downloading new e3tras, watching
recent movie trailers, web browsing, etc.
It will also be re5uired to authorize
managed co%ies of lu!ray movies that
can be transferred over a home networ4.
Disadvantages
Initially the cost will be very high
8e5uires retooling of %roduction lines.
>%grade costs might be %assed onto
consumers.
"u!!orts mandatory managed co!y
:andatory managed co%y #::-$ will be %art of
the lu!ray format. This feature will enable
consumers to ma4e legal co%ies of their lu!ray
movies that can be transferred over a home
networ4. =lease note that CmandatoryC refers to the
movies having to offer this ca%ability, while it will
be u% to each hardware manufacturer to decide if
they want to su%%ort this feature.
A!!lications
om!atibility6 <hile it is not com%ulsory for
manufacturers, the lu!ray "isc +ssociation
recommends that lu!ray "isc drives should be
ca%able of reading standard "&"s for bac4ward
com%atibility. Dor instance, Samsung2s first lu!
ray "isc drive can read and write -"s, regular
"&"s, and lu!ray "iscs. +ll other lu!ray "isc
%layers released su%%ort "&" %laybac4 as well.
"tand-alone recorders and game
controllers : The first lu!ray "isc recorder was
demoed by Sony on :arch 7, '**7, and was
introduced to the Fa%anese mar4et in +%ril that
year. The home video game console system
=layStation 7 #Sony$ is shi%%ed with a '3 lu!ray
"isc drive. The drive is read!only as is the case
with most game console o%tical drives. +ccording
to Sony2s %ress releases, it su%%orts "&" #,3$, -"
#'13$, and S+-" #'3$ formats in addition to "!
89:, "!8, and "!80.
& data storage: 9riginally, lu!ray "isc drives
in %roduction could only transfer a%%ro3imately
1.( :;s or 7? :bit;s #(1 :bit;s re5uired for "!
89:$, but '3 s%eed drives with a 9 :;s or 7'
:bit;s transfer rate are now available. 8ates of ,3
#',, :bit;s$ or more are %lanned for the future.
Dirst devices used +T +ttachment but newest ones
su%%ort Serial +T+.
onclusion
The <orld mar4et has already
e3%erienced the revolution in "igital
storage discs.
y the time :ass %roduction of lu!ray
gadgets begin its cost will fall way below
"&"s
lu!ray recorders will be -";"&";"
su%%orting
=-s with "!89:,"!8<,"!8 will
be soon mar4eted by .= O "ell.
+ll in all, be ready to witness the
80&9/>TI9E in "igital storage "iscs.
Re$erences
P1Q. =eter Eorton, RIntroduction to com%utersS,
Tata :c)raw!.ill %ublishers
'. www.howstuffwor4s.com
7. www.techcraze.net
1. www.wi4i%edia.org
(. www.blu!ray.com
?. www.blu!raydisc.com
7. www.sony.com