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The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital
optical disc In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data (bits) in the form of pits and lands on a special material, often aluminum, on one of its flat surfaces. ...
data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind of digital data and has been widely used for video programs (watched using
DVD player A DVD player is a device that plays DVDs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will also play audio CDs. DVD players are connected to a television to ...
s) or formerly for storing software and other computer files as well. DVDs offer significantly higher storage capacity than
compact disc The compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then released in Oc ...
s (CD) while having the same dimensions. A standard DVD can store up to 4.7 GB of storage, while variants can store up to a maximum of 17.08 GB. Prerecorded DVDs are mass-produced using molding machines that physically stamp data onto the DVD. Such discs are a form of DVD-ROM because data can only be read and not written or erased. Blank recordable DVD discs ( DVD-R and DVD+R) can be recorded once using a
DVD recorder A DVD recorder is an optical disc recorder that uses optical disc recording technologies to digitally record analog or digital signals onto blank writable DVD media. Such devices are available as either installable drives for computers o ...
and then function as a DVD-ROM. Rewritable DVDs (
DVD-RW DVD recordable and DVD rewritable are optical disc recording technologies. Both terms describe DVD optical discs that can be written to by a DVD recorder, whereas only 'rewritable' discs are able to erase and rewrite data. Data is written ('bur ...
,
DVD+RW DVD recordable and DVD rewritable are optical disc recording technologies. Both terms describe DVD optical discs that can be written to by a DVD recorder, whereas only 'rewritable' discs are able to erase and rewrite data. Data is written ('burn ...
, and
DVD-RAM DVD-RAM (DVD Random Access Memory) is a DVD-based disc specification presented in 1996 by the DVD Forum, which specifies rewritable DVD-RAM media and the appropriate DVD writers. DVD-RAM media have been used in computers as well as camcorders ...
) can be recorded and erased many times. DVDs are used in DVD-Video consumer digital video format and less commonly in
DVD-Audio DVD-Audio (commonly abbreviated as DVD-A) is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio uses most of the storage on the disc for high-quality audio and is not intended to be a video delivery format. The st ...
consumer digital audio format, as well as for authoring DVD discs written in a special
AVCHD AVCHD (Advanced Video Coding High Definition) is a file-based format for the digital recording and playback of high-definition video. It is H.264 and Dolby AC-3 packaged into the MPEG transport stream, with a set of constraints designed around t ...
format to hold high definition material (often in conjunction with AVCHD format
camcorder A camcorder is a self-contained portable electronic device with video and recording as its primary function. It is typically equipped with an articulating screen mounted on the left side, a belt to facilitate holding on the right side, hot-swa ...
s). DVDs containing other types of information may be referred to as DVD data discs.


Etymology

The ''
Oxford English Dictionary The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces the historical development of the English language, providing a co ...
'' comments that, "In 1995, rival manufacturers of the product initially named digital video disc agreed that, in order to emphasize the flexibility of the format for multimedia applications, the preferred abbreviation DVD would be understood to denote digital versatile disc." The OED also states that in 1995, "The companies said the official name of the format will simply be DVD.
Toshiba , commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure systems, ...
had been using the name 'digital video disc', but that was switched to 'digital versatile disc' after computer companies complained that it left out their applications." "Digital versatile disc" is the explanation provided in a DVD Forum Primer from 2000 and in the
DVD Forum The DVD Forum is an international organization composed of hardware, software, media and production companies that use and develop the DVD and formerly HD DVD formats. It was initially known as the DVD Consortium when it was founded in 1995. H ...
's mission statement, which the purpose is to promote broad acceptance of DVD products on technology, across entertainment, and other industries. Because DVDs became highly popular for the distribution of movies in the 2000s, the term ''DVD'' became popularly used in English as a
noun A noun () is a word that generally functions as the name of a specific object or set of objects, such as living creatures, places, actions, qualities, states of existence, or ideas.Example nouns for: * Living creatures (including people, alive, ...
to describe specifically a full-length movie released on the format; for example the sentence to "watch a DVD" describes watching a movie on DVD.


History


Development and launch

Released in 1987,
CD Video CD Video (also known as CDV, CD-V, or CD+V) is a format of optical media disc that was introduced in 1987 that combines the technologies of standard compact disc and LaserDisc. CD-V discs are the same size as a standard 12-cm audio CD, and conta ...
used analog video encoding on optical discs matching the established standard size of audio CDs.
Video CD Video CD (abbreviated as VCD, and also known as Compact Disc Digital Video) is a home video format and the first format for distributing films on standard optical discs. The format was widely adopted in Southeast Asia, Central Asia and the ...
(VCD) became one of the first formats for distributing ''digitally'' encoded films in this format, in 1993. In the same year, two new optical disc storage formats were being developed. One was the Multimedia
Compact Disc The compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then released in Oc ...
(MMCD), backed by
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
and
Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professiona ...
(developers of the CD and CD-i), and the other was the Super Density (SD) disc, supported by
Toshiba , commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure systems, ...
,
Time Warner Warner Media, LLC ( traded as WarnerMedia) was an American multinational mass media and entertainment conglomerate. It was headquartered at the 30 Hudson Yards complex in New York City, United States. It was originally established in 1972 by ...
, Matsushita Electric, Hitachi, Mitsubishi Electric,
Pioneer Pioneer commonly refers to a settler who migrates to previously uninhabited or sparsely inhabited land. In the United States pioneer commonly refers to an American pioneer, a person in American history who migrated west to join in settling and de ...
,
Thomson Thomson may refer to: Names * Thomson (surname), a list of people with this name and a description of its origin * Thomson baronets, four baronetcies created for persons with the surname Thomson Businesses and organizations * SGS-Thomson Mic ...
, and JVC. By the time of the press launches for both formats in January 1995, the MMCD nomenclature had been dropped, and Philips and Sony were referring to their format as Digital Video Disc (DVD). On May 3, 1995, an
ad hoc Ad hoc is a Latin phrase meaning literally 'to this'. In English, it typically signifies a solution for a specific purpose, problem, or task rather than a generalized solution adaptable to collateral instances. (Compare with '' a priori''.) C ...
, technical working group formed from five computer companies (IBM, Apple,
Compaq Compaq Computer Corporation (sometimes abbreviated to CQ prior to a 2007 rebranding) was an American information technology company founded in 1982 that developed, sold, and supported computers and related products and services. Compaq produced ...
, Hewlett-Packard, and Microsoft) issued a press release stating that they would only accept a single format. The TWG voted to boycott both formats unless the two camps agreed on a single, converged standard. They recruited
Lou Gerstner Louis Vincent "Lou" Gerstner Jr. (born March 1, 1942) is an American businessman, best known for his tenure as chairman of the board and chief executive officer of IBM from April 1993 until 2002, when he retired as CEO in March and chairman in ...
, president of IBM, to pressure the executives of the warring factions. In one significant compromise, the MMCD and SD groups agreed to adopt proposal SD 9, which specified that both layers of the dual-layered disc be read from the same side—instead of proposal SD 10, which would have created a two-sided disc that users would have to turn over. As a result, the DVD specification provided a storage capacity of 4.7 GB (4.38
GiB The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...
) for a single-layered, single-sided disc and 8.5 GB (7.92 GiB) for a dual-layered, single-sided disc. The DVD specification ended up similar to Toshiba and Matsushita's Super Density Disc, except for the dual-layer option. MMCD was single-sided and optionally dual-layer, whereas SD was two half-thickness, single-layer discs which were pressed separately and then glued together to form a double-sided disc. Philips and Sony decided that it was in their best interests to end the format war, and on September 15, 1995 agreed to unify with companies backing the Super Density Disc to release a single format, with technologies from both. After other compromises between MMCD and SD, the computer companies through TWG won the day, and a single format was agreed upon. The TWG also collaborated with the
Optical Storage Technology Association The Optical Storage Technology Association (OSTA) was an international trade association formed to promote the use of recordable optical data storage technologies and products. It was responsible for the creation and maintenance of the Universal ...
(OSTA) on the use of their implementation of the ISO-13346 file system (known as
Universal Disk Format Universal Disk Format (UDF) is an open, vendor-neutral file system for computer data storage for a broad range of media. In practice, it has been most widely used for DVDs and newer optical disc formats, supplanting ISO 9660. Due to its design ...
) for use on the new DVDs. The format's details were finalized on December 8, 1995. In November 1995,
Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...
announced it would start mass-producing DVDs by September 1996. The format launched on November 1, 1996, in Japan, mostly with
music video A music video is a video of variable duration, that integrates a music song or a music album with imagery that is produced for promotional or musical artistic purposes. Modern music videos are primarily made and used as a music marketing device ...
releases. The first major releases from
Warner Home Video Warner Bros. Home Entertainment Inc. (formerly known as Warner Home Video and WCI Home Video and sometimes credited as Warner Home Entertainment) is the home video distribution division of Warner Bros. It was founded in 1978 as WCI Home Vide ...
arrived on December 20, 1996, with four titles being available. The format's release in the U.S. was delayed multiple times, from August 1996, to October 1996, November 1996, before finally settling on early 1997. Players began to be produced domestically that winter, with March 24, 1997 as the U.S. launch date of the format proper in seven test markets. Approximately 32 titles were available on launch day, mainly from the Warner, MGM, and
New Line New is an adjective referring to something recently made, discovered, or created. New or NEW may refer to: Music * New, singer of K-pop group The Boyz Albums and EPs * ''New'' (album), by Paul McCartney, 2013 * ''New'' (EP), by Regurgitator, ...
libraries. However, the launch was planned for the following day (March 25), leading to a distribution change with retailers and studios to prevent similar violations of breaking the street date. The nationwide rollout for the format happened on August 22, 1997. DTS announced in late 1997 that they would be coming onto the format. The sound system company revealed details in a November 1997 online interview, and clarified it would release discs in early 1998. However, this date would be pushed back several times before finally releasing their first titles at the 1999 Consumer Electronics Show. In 2001, blank DVD recordable discs cost the equivalent of US$27.34 in 2022.


Adoption

Movie A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...
and home entertainment distributors adopted the DVD format to replace the ubiquitous VHS tape as the primary consumer video distribution format. Immediately following the formal adoption of a unified standard for DVD, two of the four leading
video game console A video game console is an electronic device that outputs a video signal or image to display a video game that can be played with a game controller. These may be home consoles, which are generally placed in a permanent location connected to ...
companies ( Sega and
The 3DO Company The 3DO Company (formerly THDO on the NASDAQ stock exchange), also known as 3DO, was an American video game company. It was founded in 1991 by Electronic Arts founder Trip Hawkins, in a partnership with seven other companies. After 3DO's flagsh ...
) said they already had plans to design a gaming console with DVDs as the source medium. Sony stated at the time that they had no plans to use DVD in their gaming systems, despite being one of the developers of the DVD format and eventually the first company to actually release a DVD-based console. Game consoles such as the PlayStation 2,
Xbox Xbox is a video gaming brand created and owned by Microsoft. The brand consists of five video game consoles, as well as applications (games), streaming services, an online service by the name of Xbox network, and the development arm by the ...
, and
Xbox 360 The Xbox 360 is a home video game console developed by Microsoft. As the successor to the original Xbox, it is the second console in the Xbox series. It competed with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generati ...
use DVDs as their source medium for games and other software. Contemporary games for Windows were also distributed on DVD. Early DVDs were mastered using DLT tape, but using DVD-R DL or +R DL eventually became common. TV DVD combos, combining a standard definition CRT TV or an HD flat panel TV with a DVD mechanism under the CRT or on the back of the flat panel, and VCR/DVD combos were also available for purchase. For consumers, DVD soon replaced VHS as the favored choice for home movie releases. In the year 2001, DVD players outsold VCRs for the first time in the United States. At this time 1 in 4 American households owned a DVD player. By 2007, about 80% of Americans owned a DVD player, a figure that had surpassed VCRs and was also higher than personal computers or cable television.


Specifications

The DVD specifications created and updated by the
DVD Forum The DVD Forum is an international organization composed of hardware, software, media and production companies that use and develop the DVD and formerly HD DVD formats. It was initially known as the DVD Consortium when it was founded in 1995. H ...
are published as so-called ''DVD Books'' (e.g. DVD-ROM Book, DVD-Audio Book, DVD-Video Book, DVD-R Book, DVD-RW Book, DVD-RAM Book, DVD-AR (Audio Recording) Book,
DVD-VR The DVD-VR standard defines a logical format for video recording on DVD-R, DVD-RW, and DVD-RAM style media, including the dual layer versions of these media. As opposed to media recorded with the DVD+VR recording standard, the resulting media are ...
(Video Recording) Book, etc.). DVD discs are made up of two discs; normally one is blank, and the other contains data. Each disc is 0.6 mm thick, and are glued together to form a DVD disc. The gluing process must be done carefully to make the disc as flat as possible to avoid both birefringence and "disc tilt", which is when the disc is not perfectly flat, preventing it from being read. Some specifications for mechanical, physical and optical characteristics of DVD optical discs can be downloaded as freely available standards from the
ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...
website.IS
ISO Freely Available Standards
, Retrieved on 2009-07-24
There are also equivalent
European Computer Manufacturers Association Ecma International () is a nonprofit standards organization for information and communication systems. It acquired its current name in 1994, when the European Computer Manufacturers Association (ECMA) changed its name to reflect the organization ...
(Ecma) standards for some of these specifications, such as Ecma-267 for DVD-ROMs. Also, the
DVD+RW Alliance The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind ...
publishes competing recordable DVD specifications such as DVD+R, DVD+R DL, DVD+RW or
DVD+RW DL The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital media, digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can ...
. These DVD formats are also ISO standards. Some DVD specifications (e.g. for DVD-Video) are not publicly available and can be obtained only from the DVD Format/Logo Licensing Corporation (DVD FLLC) for a fee of US$5000.DVD FLLC (2009
DVD Format Book
, Retrieved on 2009-08-14
Every subscriber must sign a non-disclosure agreement as certain information on the DVD Books is proprietary and confidential.


Double-sided discs

Borrowing from the LaserDisc format, the DVD standard includes DVD-10 discs (Type B in ISO) with two recorded data layers such that only one layer is accessible from either side of the disc. This doubles the total nominal capacity of a DVD-10 disc to 9.4 GB (8.75 GiB), but each side is locked to 4.7 GB. Like DVD-5 discs, DVD-10 discs are defined as single-layer (SL) discs.


Dual-layer discs

DVD hardware accesses the additional layer (layer 1) by refocusing the laser through an otherwise normally-placed, semitransparent first layer (layer 0). This laser refocus—and the subsequent time needed to reacquire laser tracking—can cause a noticeable pause in A/V playback on earlier
DVD player A DVD player is a device that plays DVDs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will also play audio CDs. DVD players are connected to a television to ...
s, the length of which varies between hardware. A printed message explaining that the layer-transition pause was not a malfunction became standard on DVD
keep case A keep case or poly-box is a type of packaging, most commonly used with DVDs and Blu-ray videos (and sometimes CDs). Besides DVD-Video films, keep cases are very common with most disc-based video games since the PlayStation 2, and they are al ...
s. During mastering, a studio could make the transition less obvious by timing it to occur just before a camera angle change or other abrupt shift, an early example being the DVD release of
Toy Story ''Toy Story'' is a 1995 American computer-animated comedy film directed by John Lasseter (in his feature directorial debut), produced by Pixar Animation Studios and released by Walt Disney Pictures. The first installment in the '' Toy Story ...
. Later in the format's life, larger
data buffer In computer science, a data buffer (or just buffer) is a region of a memory used to temporarily store data while it is being moved from one place to another. Typically, the data is stored in a buffer as it is retrieved from an input device (such a ...
s and faster optical pickups in DVD players made layer transitions effectively invisible regardless of mastering. Dual-layer DVDs are recorded using
Opposite Track Path DVD+R DL (DL stands for Double Layer) also called DVD+R9, is a derivative of the DVD+R format created by the DVD+RW Alliance. Its use was first demonstrated in October 2003. DVD+R DL discs employ two recordable dye layers, each capable of storin ...
(OTP).


Combinations of the above

The DVD Book also permits an additional disc type called DVD-14: a hybrid double-sided disc with one dual-layer side, one single-layer side, and a total nominal capacity of 12.3 GB. DVD-14 has no counterpart in ISO. Both of these additional disc types are extremely rare due to their complicated and expensive manufacturing. For this reason, some DVDs that were initially issued as double-sided discs were later pressed as two-disc sets. ''The above sections regarding disc types pertain to 12 cm discs. The same disc types exist for 8 cm discs: ISO standards still regard these discs as Types A–D, while the DVD Book assigns them distinct disc types. DVD-14 has no analogous 8 cm type. The comparative data for 8 cm discs is provided further down.''


DVD recordable and rewritable

HP initially developed recordable DVD media from the need to store data for backup and transport. DVD recordables are now also used for consumer audio and video recording. Three formats were developed: DVD-R/ RW, DVD+R/ RW (plus), and
DVD-RAM DVD-RAM (DVD Random Access Memory) is a DVD-based disc specification presented in 1996 by the DVD Forum, which specifies rewritable DVD-RAM media and the appropriate DVD writers. DVD-RAM media have been used in computers as well as camcorders ...
. DVD-R is available in two formats, General (650 nm) and Authoring (635 nm), where Authoring discs may be recorded with CSS encrypted video content but General discs may not.


Dual-layer recording

Dual-layer recording (occasionally called double-layer recording) allows DVD-R and DVD+R discs to store nearly double the data of a single-layer disc—8.5 and 4.7
gigabyte The gigabyte () is a multiple of the unit byte for digital information. The prefix ''giga'' means 109 in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte is GB. This defini ...
capacities, respectively. The additional capacity comes at a cost: DVD±DLs have slower write speeds as compared to DVD±R.
DVD-R DL DVD-R DL (DL stands for Dual Layer), also called DVD-R9, is a derivative of the DVD-R format standard. DVD-R DL discs hold 8.5 GB by utilizing two recordable dye layers, each capable of storing a little less than the 4.7 gigabyte (GB) of a sing ...
was developed for the
DVD Forum The DVD Forum is an international organization composed of hardware, software, media and production companies that use and develop the DVD and formerly HD DVD formats. It was initially known as the DVD Consortium when it was founded in 1995. H ...
by
Pioneer Corporation commonly referred to as Pioneer, is a Japanese multinational corporation based in Tokyo, that specializes in digital entertainment products. The company was founded by Nozomu Matsumoto in January 1, 1938 in Tokyo as a radio and speaker repair s ...
;
DVD+R DL The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any ki ...
was developed for the DVD+RW Alliance by Mitsubishi Kagaku Media (MKM) and
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
. Recordable DVD discs supporting dual-layer technology are backward-compatible with some hardware developed before the recordable medium.


Capacity

All units are expressed with SI/
IEC The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
prefixes (i.e. 1 Gigabyte = 1,000,000,000 bytes etc.).
All units are expressed with SI/
IEC The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
prefixes (i.e. 1 Gigabyte = 1,000,000,000 bytes etc.).
All units are expressed with SI/
IEC The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
prefixes (i.e. 1 Gigabyte = 1,000,000,000 bytes etc.).


DVD drives and players

DVD drives are devices that can read DVD discs on a computer.
DVD player A DVD player is a device that plays DVDs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will also play audio CDs. DVD players are connected to a television to ...
s are a particular type of devices that do not require a computer to work, and can read DVD-Video and
DVD-Audio DVD-Audio (commonly abbreviated as DVD-A) is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio uses most of the storage on the disc for high-quality audio and is not intended to be a video delivery format. The st ...
discs.


Transfer rates

Read and write speeds for the first DVD drives and players were 1,385  kB/s (1,353 
KiB The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...
/s); this speed is usually called "1×". More recent models, at 18× or 20×, have 18 or 20 times that speed. Note that for CD drives, 1× means 153.6 kB/s (150 KiB/s), about one-ninth as swift. DVDs can spin at much higher speeds than CDs – DVDs can spin at up to 32000
RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...
vs 23000 for CDs. DVD recordable and rewritable discs can be read and written using either
constant angular velocity In optical storage, constant angular velocity (CAV) is a qualifier for the rated speed of any disc containing information, and may also be applied to the writing speed of recordable discs. A drive or disc operating in CAV mode maintains a const ...
(CAV),
constant linear velocity In optical storage, constant linear velocity (CLV) is a qualifier for the rated speed of an optical disc drive, and may also be applied to the writing speed of recordable discs. CLV implies that the angular velocity (i.e. rpm) varies during an ...
(CLV), Partial constant angular velocity (P-CAV) or
Zoned Constant Linear Velocity In optical storage, constant linear velocity (CLV) is a qualifier for the rated speed of an optical disc drive, and may also be applied to the writing speed of recordable discs. CLV implies that the angular velocity (i.e. rpm) varies during an op ...
(Z-CLV or ZCLV). Due to the slightly lower data density of
dual layer Dual or Duals may refer to: Paired/two things * Dual (mathematics), a notion of paired concepts that mirror one another ** Dual (category theory), a formalization of mathematical duality *** see more cases in :Duality theories * Dual (grammatical ...
DVDs (4.25 GB instead of 4.7 GB per layer), the required rotation speed is around 10% faster for the same data rate, which means that the same angular speed rating equals a 10% higher physical angular rotation speed. For that reason, the increase of reading speeds of dual layer media has stagnated at 12× (
constant angular velocity In optical storage, constant angular velocity (CAV) is a qualifier for the rated speed of any disc containing information, and may also be applied to the writing speed of recordable discs. A drive or disc operating in CAV mode maintains a const ...
) for
half-height A drive bay is a standard-sized area for adding hardware to a computer. Most drive bays are fixed to the inside of a case, but some can be removed. Over the years since the introduction of the IBM PC, it and its compatibles have had many form ...
optical drives released since around 2005, and slim type optical drives are only able to record dual layer media at 6× (constant angular velocity), while reading speeds of 8× are still supported by such.Pioneer computer drive archive
/ref>


Disc quality measurements

The quality and data integrity of optical media is measureable, which means that future data losses caused by deteriorating media can be predicted well in advance by measuring the rate of correctable data errors. Support of measuring the disc quality varies among optical drive vendors and models.


DVD-Video

DVD-Video is a standard for distributing video/audio content on DVD media. The format went on sale in Japan on November 1, 1996, in the United States on March 24, 1997, to line up with the
69th Academy Awards The 69th Academy Awards ceremony, organized by the Academy of Motion Picture Arts and Sciences (AMPAS) took place on March 24, 1997, at the Shrine Auditorium in Los Angeles beginning at 6:00 p.m. PST / 9:00 p.m. EST. During the ceremo ...
that day; in Canada, Central America, and Indonesia later in 1997, and in Europe, Asia, Australia, and Africa in 1998. DVD-Video became the dominant form of home video distribution in Japan when it first went on sale on November 1, 1996, but it shared the market for home video distribution in the United States for several years; it was June 15, 2003, when weekly DVD-Video in the United States rentals began outnumbering weekly VHS cassette rentals. DVD-Video is still the dominant form of home video distribution worldwide except for in Japan where it was surpassed by
Blu-ray Disc The Blu-ray Disc (BD), often known simply as Blu-ray, is a Digital media, digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and c ...
when Blu-ray first went on sale in Japan on March 31, 2006.


Security

The purpose of CSS is twofold: # CSS prevents byte-for-byte copies of an
MPEG The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by International Organization for Standardization, ISO and International Electrotechnical Commission, IEC that sets standards for media coding, includ ...
(digital video) stream from being playable since such copies do not include the keys that are hidden on the lead-in area of the restricted DVD. # CSS provides a reason for manufacturers to make their devices compliant with an industry-controlled standard, since CSS scrambled discs cannot in principle be played on noncompliant devices; anyone wishing to build compliant devices must obtain a license, which contains the requirement that the rest of the DRM system ( region codes,
Macrovision TiVo Corporation, formerly known as the Rovi Corporation and Macrovision Solutions Corporation, was an American technology company. Headquartered in San Jose, California, the company is primarily involved in licensing its intellectual property ...
, and
user operation prohibition The user operation prohibition (abbreviated UOP) is a form of use restriction used on video DVD discs and Blu-ray discs. Most DVD players and Blu-ray players prohibit the viewer from performing a large majority of actions during sections of a DVD ...
) be implemented.


Successors and decline

In 2006, two new formats called
HD DVD HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to th ...
and
Blu-ray Disc The Blu-ray Disc (BD), often known simply as Blu-ray, is a Digital media, digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and c ...
were released as the successor to DVD. HD DVD competed unsuccessfully with Blu-ray Disc in the
format war A format war is a competition between similar but mutually incompatible technical standards that compete for the same market, such as for data storage devices and recording formats for electronic media. It is often characterized by political an ...
of 2006–2008. A dual layer HD DVD can store up to 30 GB and a dual layer Blu-ray disc can hold up to 50 GB. However, unlike previous format changes, e.g., vinyl to Compact Disc or VHS videotape to DVD, there is no immediate indication that production of the standard DVD will gradually wind down, as they still dominate, with around 75% of video sales and approximately one billion DVD player sales worldwide as of April 2011. In fact, experts claim that the DVD will remain the dominant medium for at least another five years as Blu-ray technology is still in its introductory phase, write and read speeds being poor and necessary hardware being expensive and not readily available. Consumers initially were also slow to adopt Blu-ray due to the cost. By 2009, 85% of stores were selling Blu-ray Discs. A high-definition television and appropriate connection cables are also required to take advantage of Blu-ray disc. Some analysts suggest that the biggest obstacle to replacing DVD is due to its installed base; a large majority of consumers are satisfied with DVDs. DVDs are also facing competition from
video on demand Video on demand (VOD) is a media distribution system that allows users to access videos without a traditional video playback device and the constraints of a typical static broadcasting schedule. In the 20th century, broadcasting in the form of o ...
services. With increasing numbers of homes having high speed Internet connections, many people now have the option to either rent or buy video from an online service, and view it by streaming it directly from that service's servers, meaning they no longer need any form of permanent storage media for video at all. By 2017, digital streaming services had overtaken the sales of DVDs and Blu-rays for the first time. Manufacturers continue to release standard DVD titles , and the format remains the preferred one for the release of older television programs and films. Shows that were shot and edited entirely on film, such as ''
Star Trek: The Original Series ''Star Trek'' is an American science fiction television series created by Gene Roddenberry that follows the adventures of the starship and its crew. It later acquired the retronym of ''Star Trek: The Original Series'' (''TOS'') to distinguis ...
'', cannot be released in high definition without being re-scanned from the original film recordings. Shows that were made between the early 1980s and the early 2000s were generally shot on film, then transferred to video tape, and then edited natively in either NTSC or PAL, making high-definition transfers impossible as these SD standards were baked into the final cuts of the episodes. '' Star Trek: The Next Generation'' is the only such show that has a Blu-ray release, as prints were re-scanned and edited from the ground up.


Longevity

Longevity of a storage medium is measured by how long the data remains readable, assuming compatible devices exist that can read it: that is, how long the disc can be stored until data is lost. Numerous factors affect longevity: composition and quality of the media (recording and substrate layers), humidity and light storage conditions, the quality of the initial recording (which is sometimes a matter of mutual compatibility of media and recorder), etc. According to
NIST The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
, " temperature of 64.4 °F (18 °C) and 40% RH elative Humiditywould be considered suitable for long-term storage. A lower temperature and RH is recommended for extended-term storage." As with CDs, the information and data storage will begin to degrade over time with most standard DVDs lasting up to 30 years depending the type of environment they are stored and whether they are full with data. According to the
Optical Storage Technology Association The Optical Storage Technology Association (OSTA) was an international trade association formed to promote the use of recordable optical data storage technologies and products. It was responsible for the creation and maintenance of the Universal ...
(OSTA), "Manufacturers claim lifespans ranging from 30 to 100 years for DVD, DVD-R and DVD+R discs and up to 30 years for DVD-RW, DVD+RW and DVD-RAM." According to a NIST/
LoC LOC, L.O.C., Loc, LoC, or locs may refer to: Places * Lóc, a village in Sângeorgiu de Pădure, Mureș County, Romania * Lócs, a village in Vas county, Hungary * Line of Contact, meeting place of Western and Eastern Allied forces at the e ...
research project conducted in 2005–2007 using
accelerated life testing Accelerated life testing is the process of testing a product by subjecting it to conditions (stress, strain, temperatures, voltage, vibration rate, pressure etc.) in excess of its normal service parameters in an effort to uncover faults and potenti ...
, "There were fifteen DVD products tested, including five DVD-R, five DVD+R, two DVD-RW and three DVD+RW types. There were ninety samples tested for each product. ... Overall, seven of the products tested had estimated life expectancies in ambient conditions of more than 45 years. Four products had estimated life expectancies of 30–45 years in ambient storage conditions. Two products had an estimated life expectancy of 15–30 years and two products had estimated life expectancies of less than 15 years when stored in ambient conditions." The life expectancies for 95% survival estimated in this project by type of product are tabulated below:Final Report: NIST/Library of Congress (LC) Optical Disc Longevity Study
, Loc.gov, September 2007 (table derived from figure 7)


See also

*
List of computer hardware This glossary of computer hardware terms is a list of definitions of terms and concepts related to computer hardware, i.e. the physical and structural components of computers, architectural issues, and peripheral devices. A ...
*
Book type The book type is a field of four bits at the start of every DVD (in the physical format information section of the control data block) that indicates what the physical format of the disc is. Many devices will use this field to determine how the d ...
* Comparison of popular optical data-storage systems *
Digital video recorder A digital video recorder (DVR) is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or networked mass storage device. The term includes set-top boxes with direct to d ...
*
Disk-drive performance characteristics Higher performance in hard disk drives comes from devices which have better performance characteristics. These performance characteristics can be grouped into two categories: access time and data transfer time (or rate). Access time The ''access ...
*
DVD authoring DVD authoring is the process of creating a DVD video capable of playing on a DVD player. DVD authoring software must conform to the specifications set by the DVD Forum. DVD authoring is the second step in the process of producing finished DVD ...
*
DVD ripper Ripping is extracting all or parts of digital content from a container. Originally, it meant to rip music out of Commodore 64 games. Later, the term was used to extract WAV or MP3 format files from digital audio CDs, but got applied as well to ...
*
DVD region code DVD region codes are a digital rights management technique introduced in 1997. It is designed to allow rights holders to control the international distribution of a DVD release, including its content, release date, and price, all according to ...
*DVD TV game –
Interactive movie Across the many fields concerned with interactivity, including information science, computer science, human-computer interaction, communication, and industrial design, there is little agreement over the meaning of the term "interactivity", but mo ...
*
Professional disc Professional Disc (PFD) is a digital recording optical disc format introduced by Sony in 2003 primarily for XDCAM, its tapeless camcorder system. It was one of the first optical formats to utilize a blue laser, which allowed for a higher densi ...
*
DVD single A music video is a video of variable duration, that integrates a music song or a music album with imagery that is produced for promotional or musical artistic purposes. Modern music videos are primarily made and used as a music marketing device ...
*
M-DISC M-DISC (Millennial Disc) is a write-once optical disc technology introduced in 2009 by Millenniata, Inc.and available as DVD and Blu-ray discs. Overview M-DISC's design is intended to provide archival media longevity.M-Disc claims that prop ...


Notes


References


Further reading

* * *


External links

* *
Dvddemystified.com: DVD Frequently Asked Questions and Answers
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