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DVD General Information
*The "Overview of DVD" paper is a
proprietary document authored by Disc Manufacturing, Inc. (DMI).
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When CD-ROM was developed over 10 years ago,
it had the ability to store over 650MB worth of data or music.
At the time, this capacity seemed almost unlimited. Most users
never dreamed they would require over 650MB. Ten years later,
the industry and consumers are pushing the 650MB barrier. Many
of today's applications call for well over 650MB of storage.
Currently, the only options available to address these needs are
compression schemes or the use of multiple discs. Each one of
these solutions has its drawbacks. Therefore, a second
generation disc technology is needed to address today's high
data requirements for video, multimedia, database, etc. The new
technology is DVD.
Early in 1995, two major groups were competing
to develop the next generation of high density compact disc.
Philips and Sony partnered and were developing one format and a
group led by Toshiba and Time Warner were developing another
format. At one point, it looked like the two groups would each
bring to market separate high density compact disc solutions.
This would have been analogous to the battle of Beta versus VHS
in the home videotape recorder industry. Another battle of this
type would not be good for the industry or the consumer.
Fortunately, in September of 1995, the two camps agreed to
develop a single standard for a high density compact disc.
The most talked about application for the new
standard disc is digital video. The goal of the entertainment
and compact disc industries is to put a full length (over 2
hours) MPEG-2 compressed motion picture onto one side of a
single CD-ROM. The current density or capacity of today's
CD-ROMs does not allow for this. Currently, only approximately
75 minutes of MPEG-1 compressed full-motion video fit onto one
"regular" CD.
In December 1995, the two groups agreed on the
official name and most of the parameters governing the new high
density compact disc. The name that was agreed upon for the new
high density disc was DVD. DVD stands for just DVD. However many
people refer to DVD as the Digital Versatile Disc or Digital
Video Disc. It should be noted that discs for the new DVD movie
players are being referred to as DVD; whereas the discs for the
computer drives are being referred to as DVD-ROM.
The agreement takes parts from both
Sony/Philips' and Toshiba/Time Warner's former separate
proposals and combines them into one. The "best
practices" compromise includes Sony/Philips' EFM-plus data
storage scheme as well as backward compatibility with current
CDs. In other words, the new DVD and DVD-ROM players must be
able to play today's current CDs.
From the Toshiba/Time Warner side, the new DVD
standard adopts their format of using two half-thickness (0.6mm)
discs bonded together for a double sided disc. The new standard
also allows for 3M's dual layer "2P" technology to be
used.
The following is a summary of the most common
DVD capacities:
4.7 GB (Single Layer Single
Side) DVD 5
8.5 GB (Dual Layer Single Side)
DVD 9
9.4 GB (Single Layer Double
Side) DVD 10
14.1 GB (DVD 9 on one side, DVD
5 on the other) DVD 14
17.0 GB (Dual Layer Double
Side) DVD 18
Therefore, the new DVD discs can store from
4.7 GB (single sided, single layer) up to 17.0 GB (double sided,
dual layer per side for a total of 4 layers of information). Each
layer of data on a DVD disc will allow up to 133 minutes of full
motion MPEG-2 video. This amount of playing time will
allow 95% of all movies to be contained on one side of a disc.
This new disc will also support a variable bit data rate which
will increase the quality of digital video playback thanks to a
substantial buffer memory. The new DVD movie players are also
capable of seamless switching between the two layers of
information on each side of the disc.
DLT (Digital Linear Tape) is
used as "source" to send in the large quantity of data
to be mastered into DVD. DLT tape cartridges are slightly larger
than 8mm tape cartridges but smaller than VHS cartridges. There
are different densities of DLT tape with the highest capacities
holding up to 20GB per tape (uncompressed). Other types of tapes
and transfer media are under development to support DVD.
Cutting a full 4.7GB single layer of a DVD
disc today at the fastest encoding speeds available takes over
90 minutes. As the mastering software and hardware are improved,
this time will decrease. Remember, a full DVD disc could contain
up to four mastered layers of information. A mastering cut must
be done for each layer of information put onto a DVD disc.
Therefore, as the number of layers of information increases, so
will the mastering cost and time.
Some of the problems that threaten to delay
the quick acceptance of DVD in the marketplace are the
following:
*Copy Protection
The movie industry will not allow movies to be
distributed on DVD until there is a way to ensure that the
content on the discs are relatively protected. The industry
mainly wants to ensure that the DVD disc is protected from
digital to digital transfers and from digital to analog
transfers (DVD to VHS for example). Fortunately the major
players agreed in October 1996 on the basics for copy
protection. To protect from the straight digital to digital
transfers the industry has chosen to encrypt the DVD movie data.
Special decryption technology must be used to be able to
successfully play back the DVD movie information.
To protect against digital to analog transfers
of DVD movie information the industry will use similar
technology that is in use today to prevent VHS tape to tape
copying. This technology allows the video information to be
viewed, however when this same information is copied to a tape
it is degraded to a non viewable level in most cases.
*Regional Coding
The movie industry is also planning on using
special regional codes on the DVD movie discs to control
distribution. These codes which will be in the discs will allow
the industry to control when and where movies will be released.
Six separate regional codes are currently being considered.
*Licensing
There are still some issues to be worked out
by all the major parties concerning licensing. Most people in
the industry were hoping that a one stop licensing scheme could
be worked out to simplify the licensing process. However at this
date it looks like some of the players are thinking of licensing
their technology separately. This could add to the cost of the
overall DVD players and discs.
*Today’s CD-Rs Might Not Play on DVD Drives
Due to the change in wavelength on the
playback laser for DVD players today’s CD-Rs might not play on
some DVD drives. This could be a serious problem for the quick
acceptance of DVD in the marketplace. Changing the reflectivity
on newly manufactured CD-Rs would solve this problem. However
this would still leave many thousands or millions of unplayable
CD-Rs in the market. Some manufacturers are planning on putting
two laser optical pickups on their new DVD drives. One would be
at the old wavelength and would be able to play today’s CD-Rs.
The other would be at the new wavelength and would play DVDs.
This would of course add cost to the drive however it would
completely solve this backward compatibility issue.
The file structure on a DVD will be Micro UDF
(Universal Disk Format) initially combined with ISO 9660.
Eventually Micro UDF will become the standard file format used
for DVD. The Micro UDF file format will extend and modify what
is currently possible with ISO 9660.
The decision to standardize on a single high
density digital (video) disc (which has the potential to be a$50
billion a year market) is very good news for computer, consumer
electronics, and entertainment companies. Until the compromise
was reached, DVD projections were for a slow, limited roll-out,
with the new format not really taking hold until the end of the
decade. Now, post-convergence sales projections are more
optimistic.
DVD discs and players (DVD and DVD-ROM) became
available in the 4th quarter 1996. The first players appeared in
Japan. The cost of the DVD movie players are between $500 and
$1000. The cost of the DVD-ROM drives are between $300 and $600.
Widespread availability of the DVD movie and ROM players will
happen in early 1997.
Disc Manufacturing, Inc. has already
successfully mastered and manufactured DVD discs based on the
specification information available to date. DMI has developed a
prototype line that is available to manufacture DVD and DVD-ROM
discs in quantity.
After the appearance of DVD and DVD-ROM
players, the industry's next creation will be DVD-R (Recordable)
discs and DVD-RAM (Rewritable) discs. DVD-R discs are projected
to hold up to 3.8 GB/layer and have up to two layers. DVD-RAM
discs are projected to be two sided and have up to 2.6 GB/side.
Follow this
link for specifications on how to submit your data to CD
Solutions, Inc. for replication of your DVD project!
There are two
DVD-Recorders from Pioneer. The first is the DVDRS201
which is a professional DVD recorder that makes discs which are
acceptable by most DVD replication facilities. The
second is the DVR-A03 which is a
"general purpose" recorder. It plays in nearly
all DVD players but is not accepted by replication plants as a
source discs because it lacks certain header information needed
by the replication equipment. Pioneer maintains that these
two product lines will both exist but time will tell. With
the large price difference it will be hard to maintain the
higher priced justification of the DVDRS201. Also get your
questions answered about the new consumer DVD recorder here.
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2002-03 CD Solutions Inc., All Rights Reserved.
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