Super Audio CD
China Video Disc
Video Single Disc
('Digital Versatile Disc', once 'Digital Video
Disc', and now, officially standing for nothing according to DVD
Demystified) is an optical disc storage media format that can be used for
data storage, including movies with high video and sound quality. DVDs
resemble compact discs as their physical dimensions are the same (120 mm
(4.72 inches) or occasionally 80 mm (3.15 inches) in diameter) but they
are encoded in a different format and at a much higher density. The
official DVD specification is maintained by the DVD
In the early 1990s two high-density optical
storage standards were being developed: one was the MultiMedia Compact
Disc (MMCD), backed by Philips and Sony, and the other was the Super
Density disc (SD), supported by Toshiba, Time-Warner, Matsushita Electric,
Hitachi, Mitsubishi Electric, Pioneer, Thomson, and JVC. IBM's president,
Lou Gerstner, acting as a matchmaker, led an effort to unite the two camps
behind a single standard, anticipating a repeat of the costly format war
between VHS and Betamax in the 1980s.
Philips and Sony abandoned
their MMCD format (not to be confused with MultiMediaCards) and agreed
upon Toshiba's SD format (not to be confused with secure digital cards)
with two modifications that are both related to the servo tracking
technology. The first one was the adoption of a pit geometry that allows
'push-pull' tracking, a proprietary Philips/Sony technology. The second
modification was the adoption of Philips' EFMPlus. EFMPlus, created by
Kees Immink, who also designed EFM, is 6% less efficient than Toshiba's SD
code, which resulted in a capacity of 4.7 GB as opposed to SD's original 5
GB. The great advantage of EFMPlus is its great resilience against disc
damage such as scratches and fingerprints. The result was the DVD
specification Version 1.5, announced in 1995 and finalized in September
1996. In May 1997, the DVD Consortium was replaced by the DVD Forum, which
is open to all companies.
'DVD' was originally an
initialism for 'Digital Versatile Disc.' Many non industry consumers
believe that it stands for 'Digital Video Disc' however the format was not
specifically for video but rather computer data. At the time there were
few commercial computer application that would require the size of a DVD,
however there was one for video; because video popularized the DVD format
consumers mistakenly refer to it as Digital Video Disc.
Warner Home Video and
Toshiba introduced the new format to Wall Street types, Hollywood bigwigs
and the investment community at an elaborate staged event on the Warner
Bros. lot, hosted by Warner Home Video's then president Warren Lieberfarb.
The production included the first ever interactive DVD menu designed by
producer Billy Pollina. The first DVD players and discs were available in
November 1996 in Japan, March 1997 in the United States, 1998 in Europe
and in 1999 in Australia. The first pressed DVD release was the film
Twister in 1996. The film had the first test for 2.1 surround sound. The
first titles released in the U.S., on March 19, 1997, by Lumivision,
authored by AIX Entertainment, were IMAX adaptations: Africa: The
Serengeti, Antarctica: An Adventure of a Different Nature, Tropical
Rainforest, and Animation Greats.
By the early part of 1999
the price of a DVD player had dropped below $300 US. At that point
Wal-Mart began to offer DVD players for sale, but DVDs represented only a
small part of their video inventory; VHS tapes of films made up the
remainder. Wal-Mart's competitors followed suit, and DVDs began to
increase in popularity with American consumers.
DVD rentals first topped
those of VHS during the week of June 15, 2003 (27.7 M rentals DVD vs. 27.3
M rentals VHS). Major U.S. retailers Circuit City and Best Buy stopped
selling pre-recorded VHS tapes in 2002 and 2003, respectively. In June
2005, Wal-Mart and several other retailers announced plans to phase out
the VHS format entirely, in favor of the more popular DVD format, however
as of late 2006 Wal-Mart still has a very small stock of VHS Movie titles.
Blank VHS tapes are still widely available since DVD video recorders are
significantly less common than VHS recorders. Many films released to
theaters from 2004 onwards are released solely to DVD format and not to
While the growth of
theatrical films on DVD has cooled recently, that of television programs
and music video has increased dramatically. The price of a DVD player has
dropped to below the level of a typical VCR (although DVD recorders are
still usually more expensive than VCRs); a low-end player with reasonable
quality can be purchased for under $35 US in many retail stores and many
modern computers are sold with DVD-ROM drives. Also popular are units that
have integrated a DVD and VHS VCR into a single device; these can be
purchased for under $100 US. Most, but not all, movie 'sets' or series
have been released in boxed sets, as have some entire seasons or selected
episode volumes of older and newer television programs.
Format in video
Sony's PlayStation 2,
released in 2000, was the first console with a DVD drive; in addition to
playing video games, it was also able to play DVD movies. This proved to
be a huge selling point and helped boost DVD sales, as the PS2 cost less
than most DVD players in Japan. As a result, many electronic stores that
normally did not carry video game consoles carried PS2s. Despite many
reports of poor and bad playback and green screens, this proved popular
and was often used as a primary DVD player until the prices of good
standalone players went down.
The DVD drive gave the PS2
an edge over its main rival at the time: Sega's Dreamcast, which instead
used a proprietary media called GD-ROM. At a point, Sega displayed a
prototype add-on DVD drive for the Dreamcast; however, since it was never
showed working, it is frequently rumored that it was just an empty shell.
Ultimately, no such unit was ever released. Some stores offered a bundle
of the Dreamcast and a regular DVD video player, which helped clear the
stock when the Dreamcast was discontinued in 2001.
In keeping with this
approach, Sony will incorporate Sony's competing successor to DVD,
Blu-ray, into its next console, the PlayStation 3. Problems with
implementing this and its Digital Rights Management are the official
reason for the delay in launching the system.
Microsoft's Xbox, released
in 2001 in the U.S. and on March 13, 2002 in Europe, had the capability to
play DVD discs with an add-on remote control kit, cementing DVD's place in
video game consoles. Nintendo's GameCube, released on May 3, 2002 in
Europe and on November 18, 2001 in the US, cannot play DVDs but uses a
proprietary 3-inch optical disc for its game media. However, a version of
the GameCube known as the Panasonic Q (sold only in Japan) plays DVDs.
With the Xbox 360, the successor to the Xbox, which was released worldwide
in November 2005, DVD playback is built in. A HD-DVD Drive add-on is to be
be released in late 2006 to play HD-DVD movies. There will be no games
released in this format. DVD playback will be available on the upcoming
PlayStation 3 as standard, but Nintendo's Wii console, which will use a
proprietary 4.5 inch disc for its game media, has been confirmed to be
compatible with DVDs at launch, but only in Japan. The Playstation 3
launched in Japan on the 11th of november following the releases in the
U.S. in late November 2006 and in Europe in March 2007, with the rest of
the world to follow.
The four basic types of
DVD are referred to by their capacity in gigabytes, rounded up to the
nearest integer. The exception to the rule is DVD-18, whose capacity is in
fact 17 gigabytes.
Single sided, single layer
Single sided, dual layer
Double sided, single layer
Double sided, dual layer
HP initially developed recordable DVD media from
the need to store data for back-up and transport.
DVD recordables are now
also used for consumer audio and video recording. Three formats were
developed: -R/RW (dash), +R/RW (plus), -RAM (random access
Dual Layer recording
allows DVD-R and DVD+R discs to store significantly more data, up to 8.5
Gigabytes per disc, compared with 4.7 Gigabytes for single-layer discs.
DVD-R DL (dual layer — see figure) was developed for the DVD Forum by
Pioneer Corporation, DVD+R DL (double layer — see figure) was developed
for the DVD+RW Alliance by Sony.
A Dual Layer disc differs
from its usual DVD counterpart by employing a second physical layer within
the disc itself; how the drive with Dual Layer capability accesses the
second layer is that it could shine the laser through the first
semi-transparent layer -- This is something that normal DVD recordable
discs do not have. The layer change mechanism in some DVD players can show
a noticeable pause, as long as two seconds by some accounts. More than a
few viewers have worried that their dual layer discs were damaged or
DVD recordable discs
supporting this technology are backward compatible with some existing DVD
players and DVD-ROM drives. Many current DVD recorders
support dual-layer technology, and the price point is comparable to that
of single-layer drives, though the blank media remains significantly more
Each DVD-Video disc
contains one or more region codes, denoting the area[s] of the world in
which distribution and playback are intended. The commercial DVD player
specification dictates that a player must only play discs that contain its
region code. In theory, this allows the motion picture studios to control
the various aspects of a release (including content, date and price) on a
region-by-region basis, or ensure the success of 'staggered' or late
theatrical releases from country to country. For example, the movie 28
Days Later was released on DVD in Europe several months prior to the
film's theatrical release in North America. Regional coding kept the
European DVD unplayable for most North American consumers, thereby
ensuring that ticket sales would be relatively unaffected by the late
theatrical release. To many, this is no more than an objectionable barrier
to trade. As a result many websites offer methods with which consumers can
by-pass such restrictions.
In practice, many DVD
players allow playback of any disc, or can be modified to do so. Entirely
independent of encryption, region coding pertains to regional lockout,
which originated in the video game industry.
From a worldwide
perspective regional coding may be seen as a failure. A huge percentage of
players outside of North America can be easily modified (and are even sold
pre-modified by mainstream stores such as Amazon.co.uk) to ignore the
regional codes on a disc. This, coupled with the fact that almost all
televisions in Europe and Australasia are capable of displaying NTSC
video, means that consumers in these regions have a huge choice of discs.
Contrary to popular belief, this practice is not illegal and in some
countries that strongly support free trade (New Zealand is one prominent
example) it is encouraged.
A normal DVD player can
only play region-coded discs designated for the player's own particular
region. However, a code-free or region-free DVD player is capable of
playing DVD discs from any of the six regions around the
In the US, most low-cost
DVD players that are sold in supermarkets or other cheap outlets are not
multi-region. Some of the more expensive players (e.g. Sony) are
multi-region. Conversely in the UK and Ireland many cheap DVD players are
multi-region while more expensive systems, including the majority of home
cinema systems, are preset to play only region 2 discs.
DVD-Audio is a format for
delivering high-fidelity audio content on a DVD. It offers many channel
configuration options (from mono to 5.1 surround sound) at various
sampling frequencies and sample rates. Compared with the CD format, the
much higher capacity DVD format enables the inclusion of either
considerably more music (with respect to total running time and quantity
of songs) or far higher audio quality (reflected by higher linear sampling
rates and higher vertical bit-rates, and/or additional channels for
spatial sound reproduction).
superior technical specifications, there is debate as to whether or not
the resulting audio enhancements are distinguishable to typical human
ears. DVD-Audio currently forms a niche market, probably due to its
dependency upon new and relatively expensive equipment.
DVD-Audio discs employ a
robust copy prevention mechanism, called Content Protection for
Prerecorded Media (CPPM) developed by the 4C group (IBM, Intel,
Matsushita, and Toshiba).
CPPM can be circumvented
on a PC by capturing decoded audio streams in PCM format, but the
underlying protection mechanism, encryption algorithms, and keys have not
yet been cracked.
Modern DVD recorders often
support additional formats, including DVD+/-R/RW, CD-R/RW, MP3, WMA, SVCD,
JPEG, PNG, SVG, KAR and MPEG-4 (DivX/XviD). Some also include USB ports or
flash memory readers. Many players are priced from under $/€ 25 and
recorders from $/€ 50.
DVD drives for computers
usually come with one of two kinds of Regional Playback Control (RPC),
either RPC-1 or RPC-2; This is used to enforce the publisher's
restrictions on what regions of the world the DVD can be played. See
There are several possible
successors to DVD being developed by different consortiums:
Sony/Panasonic's Blu-ray Disc (BD), Toshiba's HD DVD and Maxell's
Holographic Versatile Disc (HVD).
The first generation of
holographic media with 300 GB of storage capacity and a 160 Mbit/s
transfer rate is scheduled for release in late 2006 by Maxell and its
On November 18, 2003, the
Chinese news agency Xinhua reported the final standard of the Chinese
government-sponsored Enhanced Versatile Disc (EVD), and several patents
for it. However, since then the format has generally failed to live up to
On November 19, 2003, the
DVD Forum decided by a vote of eight to six that HD DVD will be its
official HDTV successor to DVD. This had no effect on the competing
Blu-ray Disc Association's (BDA) determination that its format would
succeed DVD, especially since most of the voters belonged to both
On April 15, 2004, in a
co-op project with TOPPAN Printing Co., the electronics giant Sony Corp.
successfully developed the paper disc, a storage medium that is made out
of 51% paper and offers up to 25 GB of storage, about five times more than
the standard 4.7 GB DVD. The disc can be easily cut with scissors and
recycled, offering foolproof data security and an environment-friendly
As reported in a mid 2005
issue of Popular Mechanics, it is not yet clear which technology will win
the format war over DVD. HD DVD discs have a lower capacity than Blu-ray
discs (15 GB vs. 25 GB for single layer, 30 GB vs. 50 GB for dual layer),
but Blu-ray requires changes in manufacturing machinery and techniques and
is thus more expensive.
In April, 2000, Sonic
Solutions and Ravisent announced hDVD, an HDTV extension to DVD that
presaged the HD formats that debuted 6 years later.
new formats fighting as the successor to a format approaching purported
obsolescence—previously appeared as the 'war of the speeds' in the record
industry of the 1950s. It is also, of course, similar to the VHS/Betamax
war in consumer video recorders in the late 1980s.
It is possible that
neither Blu-ray, HD DVD, nor a next-generation optical recording products
will succeed. The storage capacities of hard disk drives and solid-state
memory have grown faster than those of optical discs (since CD's
introduction year, 1983, storage capacity of HDDs grew by a factor of
about 150,000, from 5 MB to 750 GB, while the capacity of Blu-ray is only
90 times larger than CD), and all three are much more capable of storing
general consumer content —such as photos, music, and video— than in the
past. Hard disk drives having a few terabytes of storage capacity will be
on the market before 2008. A terabyte is equivalent to about 2000 CD-ROMs,
130 DVD-9s, or 20 dual-layer BDs. However, hard disk drives and memory
cards are at the moment hundreds of times more expensive than optical
discs (US$50 or more compared to $0.50). The price per gigabyte of a hard
disk drive, $0.40 ($200/500 GB), is growing closer to that of a DVD-ROM,
$0.06 ($0.50/8.5 GB); BD-ROM, $0.03 ($1.50/50 GB); recordable DVD-5, $0.10
($0.50/4.7 GB); or recordable DVD-9, $0.30 ($2.50/8.5 GB); and is lower
than the cost of a BD-RE25, $1.20 ($30/25 GB). Direct access to large
amounts of information is much more convenient with a hard disk drive. As
broadband becomes fast enough (40 Mbit/s and higher) and more widely
available, physical media will become less important as a distribution
One last possibility is
that DVD will not be replaced in terms of Home Theatre by any format
currently developed. People may not be so keen to upgrade their DVD
collection so (relatively) soon. DVD may remain the format of choice for
many more years, which may lead to the creation of a better technology
that will replace it.
The new generations of
optical formats have restricted access (anti-copy mechanisms), and it is
therefore possible that consumers may ignore
Wikipedia information about
DVD. This article is licensed under the GNU Free Documentation License . It uses material
from the Wikipedia article 'DVD'
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