DVD
Encyclopedia
A DVD is an optical disc
storage
media format, invented and developed by Philips
, Sony
, Toshiba
, and Panasonic
in 1995. DVDs offer higher storage capacity than Compact Disc
s while having the same dimensions.
Pre-recorded DVDs are mass-produced using molding machines
that physically stamp data onto the DVD. Such discs are known as DVD-ROM
, because data can only be read and not written nor erased. Blank recordable DVDs (DVD-R
and DVD+R
) can be recorded once using optical disc recording technologies
and supported by optical disc drives and DVD recorder
s and then function as a DVD-ROM. Rewritable DVDs (DVD-RW
, DVD+RW
, and DVD-RAM
) can be recorded and erased multiple times.
DVDs are used in DVD-Video
consumer digital video format and in DVD-Audio
consumer digital audio format, as well as for authoring AVCHD discs. DVDs containing other types of information may be referred to as DVD data discs.
(VCD) became the first format for distributing digitally encoded films on standard 120 mm optical discs. (Its predecessor, CD Video
, used analog video encoding.) VCD was on the market in 1993.
In the same year, two new optical disc storage formats were being developed. One was the Multimedia Compact Disc
(MMCD), backed by Philips
and Sony
, and the other was the Super Density (SD) disc, supported by Toshiba
, Time Warner
, Matsushita Electric, Hitachi
, Mitsubishi Electric
, Pioneer
, Thomson
, and JVC
.
Regarding writable media, long before the invention of even CD-R, optical Write Once Read Many
(WORM) drives were used that used 12" disks in a cartridge. These WORM disks used an ablative
technology to store data.
Representatives of the SD camp approached IBM, asking for advice on the file system to use for their disc as well as seeking support for their format for storing computer data. Alan E. Bell
, a researcher from IBM's Almaden Research Center
got that request and also learned of the MMCD development project. Wary of being caught in a repeat of the costly videotape format war
between VHS
and Betamax
in the 1980s, he convened a group of computer industry experts, including representatives from Apple, Microsoft
, Sun
, Dell
, and many others. This group was referred to as the Technical Working Group, or TWG.
The TWG voted to boycott both formats unless the two camps agreed on a single, converged standard. Lou Gerstner, president of IBM, was recruited to apply pressure on the executives of the warring factions. Eventually, the computer companies won the day, and a single format, now called DVD, was agreed upon. The TWG also collaborated with the Optical Storage Technology Association
(OSTA) on the use of their implementation of the ISO-13346 file system (known as Universal Disc Format) for use on the new DVDs.
Philips and Sony decided it was in their best interest to avoid another format war over their Multimedia Compact Disc, and agreed to unify with companies backing the Super Density Disc to release a single format with technologies from both. The specification was mostly 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 single-layer but optionally double-sided) and EFMPlus
modulation.
EFMPlus was chosen because of its great resilience to disc damage, such as scratches and fingerprints. EFMPlus, created by Kees Immink
(who also designed EFM
), is 6% less efficient than the modulation technique originally used by Toshiba, which resulted in a capacity of 4.7 GB, as opposed to the original 5 GB. The result was the DVD specification, finalized for the DVD movie player and DVD-ROM computer applications in December 1995.
The DVD Video format was first introduced by Toshiba in Japan in November 1996, in the United States in March 1997 (test marketed), in Europe in October 1998, and in Australia in February 1999.
In May 1997, the DVD Consortium was replaced by the DVD Forum
, which is open to all other companies.
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 Book, DVD-VR
Book, etc.).
Some specifications for mechanical, physical and optical characteristics of DVD optical discs can be downloaded as freely available standards from the ISO website. Also, the DVD+RW Alliance
publishes competing DVD specifications such as DVD+R, DVD+R DL, DVD+RW or DVD+RW DL. These DVD formats are also ISO standards.
Some of DVD specifications (e.g. for DVD-Video) are not publicly available and can be obtained only from the DVD Format/Logo Licensing Corporation for a fee of US $5000. Every subscriber must sign a non-disclosure agreement
as certain information in the DVD Book is proprietary and confidential.
DVD was originally used as an initialism for the unofficial term
digital videodisc.
A newsgroup FAQ
written by Jim Taylor (a prominent figure in the industry) claims that four years later, in 1999, the DVD Forum stated that the format name was simply the three letters "DVD" and did not stand for anything.
The DVD Forum
website has a section called "DVD Primer" in which the answer to the question, "What does DVD mean?" reads, "The keyword is 'versatile.' Digital Versatile Discs provide superb video, audio and data storage and access—all on one disc."
(MID). The MID contains pre-recorded information as to who really manufactures the disc, under a certain brand name that the consumer is more familiar with. Also included is the byte capacity and permitted burning speeds (dependent on both the recorder, or burner, as well as what the disc can handle). This information can be read on many disc authoring software, such as ImgBurn.
A MID code is generally seen to be more reassuring for individuals whose priority is the long term storage of their data than just a buying for brand name sake. However, not all MID codes are produced in the same way. For example internet club Club MyCE specialises in disc burning consensually swear that anything not produced by Japanese disc manufacturers Verbatim or Taiyo Yuden will be of inferior burning quality and offer lower longtivity than people who burn Verbatim or Taiyo Yuden discs.
This is for many reasons. Verbatim and Taiyo Yuden have high quality standards to ensure their discs are excellent, (and anything that fails their strict quality regulation often gets destroyed) whilst other famous disc manufacturers, such as CMC Magnetics Corporation or Ritek Corporation tend to produce to vary per batch, resulting in inconsistency and poor burning results. Another reason is the burner's firmware; a set of instructions varying from burner to burner as to how to interact with the disc. They determine how well a burn will be, or even if it will finish at all. A burn that fails to record during burning, or verifying, is referred to as a "coaster" - or an unusable disc. Several errors as such may be encountered when trying to play back the disc.
Additionally, it is the firmware that determines how well it supports the MID code. Samsung and BenQ burners for example tend to be more tolerant of less well known MID codes, whilst a LG and a Matsushita burner (made by parent company Panasonic) might be a little pickier over what it can handle.
As a result, many disc producers have turned to "faking" mid codes in order to obtain better firmware support. UmeDisc, who produce discs on behalf of AOne, Tesco, Signellex, etc. may turn to faking a Taiyo Yuden MID or a Mitsubishi MKM MID (manufacturer for Verbatim) so the burner can interpret it better. An AOne 8x DVD-R disc uses a Taiyo Yuden MID, (TYG02) although its real MID code should be UME01.
The cheaper brand of discs may turn to "outsourcing" their products. This is where a brand name of disc changes the manufacturer depending on who on will sell them a batch of discs at the lowest price. Memorex is quite famous for changing their manufacturers on a regular occasion, (one spindle of DVD blanks may be produced by one manufacturer whilst another spindle may be produced by another). Brands who outsource tend to obtain the lowest quality batch of spindle, and thus makes them inconsistent for long term, let alone for burning.
However, some brands of discs remain loyal to their supplier. Traxdata and Arita are Ritek-only brands, whilst Datasafe and Datawrite are firm with CMC Magnetics.
. When the price point for a LaserDisc at approximately $100 per disc moved to $20 per disc at retail, this luxury feature became available for mass consumption. Simultaneously, the movie studios decided to change their home entertainment release model from a rental model to a for purchase model, and large numbers of DVDs were sold.
At the same time, a demand for interactive design talent and services was created. Movies in the past had uniquely designed title sequences. Suddenly every movie being released required information architecture and interactive design components that matched the film's tone and were at the quality level that Hollywood demanded for its product.
The basic types of DVD (12 cm diameter, single-sided or homogeneous double-sided) are referred to by a rough approximation of their capacity in gigabytes. In draft versions of the specification, DVD-5 indeed held five gigabytes, but some parameters were changed later on as explained above, so the capacity decreased. Other formats
, those with 8 cm diameter and hybrid variants, acquired similar numeric names with even larger deviation.
The 12 cm type is a standard DVD, and the 8 cm variety is known as a MiniDVD
. These are the same sizes as a standard CD and a mini-CD
, respectively. The capacity by surface (MiB/cm2) varies from 6.92 MiB/cm2 in the DVD-1 to 18.0 MiB/cm2 in the DVD-18.
As with hard disk drives, in the DVD realm, gigabyte
and the symbol GB are usually used in the SI
sense (i.e., 109, or 1,000,000,000 bytes). For distinction, gibibyte
(with symbol GiB) is used (i.e., 10243 (230), or 1,073,741,824 bytes).
Each DVD sector contains 2,418 bytes of data, 2,048 bytes of which are user data. There is a small difference in storage space between + and - (hyphen) formats:
DVD uses 650 nm wavelength laser diode
light as opposed to 780 nm for CD. This permits a smaller pit to be etched on the media surface compared to CDs (0.74 µm for DVD versus 1.6 µm for CD), allowing in part for DVD's increased storage capacity.
In comparison, Blu-ray Disc
, the successor to the DVD format, uses a wavelength of 405 nm, and one dual-layer disc has a 50 GB storage capacity.
Writing speeds for DVD were 1×, that is, 1,385 kB
/s (1,353 KiB
/s), in the first drives and media models. 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.
This mechanism is shown right side up; the disc would sit on top of it. The laser and optical system scans the underside of the disc.
With reference to the photo, just to the right of image center is the disc spin motor, a gray cylinder, with its gray centering hub and black resilient drive ring on top. A clamp (not in the photo, retained in the drive's cover), pulled down by a magnet, clamps the disc when this mechanism rises, after the disc tray stops moving inward. This motor has an external rotor – every visible part of it spins.
The gray metal chassis is shock-mounted at its four corners to reduce sensitivity to external shocks, and to reduce drive noise when running fast. The soft shock mount grommets are just below the brass-colored washers at the four corners (the left one is obscured). Running through those grommets are screws to fasten them to the black plastic frame that's underneath.
Two parallel precision guide rods that run between upper left and lower right in the photo carry the "sled
", the moving optical read-write head. As shown, this "sled" is close to, or at the position where it reads or writes at the edge of the disc.
A dark gray disc with two holes on opposite sides has a blue lens surrounded by silver-colored metal. This is the lens that's closest to the disc; it serves to both read and write by focusing the laser light to a very small spot. It is likely that this disc rotates half a turn to position a different set of optics (the other "hole") for CDs vs. DVDs.
Under the disc is an ingenious actuator comprising permanent magnets and coils that move the lens up and down to maintain focus on the data layer. As well, the actuator moves the lens slightly toward and away from the spin-motor spindle to keep the spot on track. Both focus and tracking are relatively quite fast and very precise. The same actuator rotates the lens mount half a turn as described.
To select tracks (or files) as well as advancing the "sled" during continuous read or write operations, a stepping motor rotates a coarse-pitch leadscrew to move the "sled" throughout its total travel range. The motor, itself, is the gray cylinder just to the left of the most-distant shock mount; its shaft is parallel to the support rods. The leadscrew, itself, is the rod with evenly-spaced darker details; these are the helical groove that engages a pin on the "sled".
The irregular orange material is flexible etched copper foil supported by thin sheet plastic; these are "flexible printed circuits" that connect everything to the electronics (which is not shown).
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-R is available in two formats, General (650 nm) and Authoring (635 nm), where Authoring discs may be recorded with encrypted content but General discs may not.
Although most DVD writers can nowadays write the DVD+R/RW and DVD-R/RW formats (usually denoted by "DVD±RW" and/or the existence of both the DVD Forum logo and the DVD+RW Alliance logo), the "plus" and the "dash" formats use different writing specifications. Most DVD readers and players will play both kinds of discs, although older models can have trouble with the "plus" variants.
Some first generation DVD player
s would cause damage to DVD±R/RW/DL when attempting to read them.
and DVD+R
discs to store significantly more data—up to 8.54 gigabyte
s per disc, compared with 4.7 gigabytes for single-layer discs. Along with this, DVD-DLs have slower write speeds as compared to ordinary DVDs and when played on a DVD player a slight transition can sometimes be seen between the layers. DVD-R DL
was developed for the DVD Forum by Pioneer Corporation
; DVD+R DL
was developed for the DVD+RW Alliance by Philips
and Mitsubishi Kagaku Media (MKM).
A dual-layer disc differs from its usual DVD counterpart by employing a second physical layer within the disc itself. The drive with dual-layer capability accesses the second layer by shining the laser through the first semitransparent layer. In some DVD players, the layer change can exhibit a noticeable pause, up to several seconds. This caused some viewers to worry that their dual-layer discs were damaged or defective, with the end result that studios began listing a standard message explaining the dual-layer pausing effect on all dual-layer disc packaging.
DVD recordable discs supporting this technology are backward-compatible with some existing DVD players and DVD-ROM drives. Many current DVD recorder
s support dual-layer technology, and the price is now comparable to that of single-layer drives, although the blank media remain more expensive. The recording speeds reached by dual-layer media are still well below those of single-layer media. A potential reason is how Dual Layer discs are not as well matured compared to the Single Layer discs, as well as consumers, on a whole, have no desire for increased burning speeds.
There are two modes for dual-layer orientation. With Parallel Track Path (PTP), used on DVD-ROM, both layers start at the inside diameter (ID) and end at the outside diameter (OD) with the lead-out. With Opposite Track Path
(OTP), used on many Digital Video Discs, the lower layer starts at the ID and the upper layer starts at the OD, where the other layer ends; they share one lead-in and one lead-out.
Currently, DVD-Video is the dominant form of home video distribution worldwide, although in Japan it was surpassed by Blu-ray Disc
when Blu-ray first went on sale in Japan on March 31, 2006.
(DRM) and encryption
system employed on almost all commercially produced DVD-video discs. CSS utilizes a proprietary 40-bit stream cipher
algorithm. The system was introduced around 1996 and was first compromised in 1999.
The purpose of CSS is twofold:
While most CSS-decrypting software is used to play DVD videos, other pieces of software (such as DVD Decrypter
, AnyDVD
, DVD43
, Smartripper, and DVD Shrink
) can copy a DVD to a hard drive and remove Macrovision
, CSS encryption, region codes
and user operation prohibition
.
" has prompted many copyright holders to display notices on DVD packaging or displayed on screen when the content is played that warn consumers of the illegality of certain uses of the DVD. It is commonplace to include a 90 second advert warning that most forms of copying the contents are illegal. Many DVDs prevent skipping past or fast-forwarding through this warning.
Arrangements for renting and lending differ by geography. In the U.S., the right to re-sell, rent, or lend out bought DVDs is protected by the first-sale doctrine
under the Copyright Act of 1976
. In Europe, rental and lending rights are more limited, under a 1992 European Directive that gives copyright holders broader powers to restrict the commercial renting and public lending of DVD copies of their work.
to 5.1 surround sound
) at various sampling frequencies (up to 24-bits/192 kHz versus CDDA's 16-bits/44.1 kHz). Compared with the CD format, the much higher-capacity DVD format enables the inclusion of considerably more music (with respect to total running time and quantity of songs) and/or far higher audio quality (reflected by higher sampling rate
s and greater sample resolution, and/or additional channels for spatial sound reproduction).
Despite DVD-Audio's superior technical specifications, there is debate as to whether the resulting audio enhancements are distinguishable in typical listening environments. DVD-Audio currently forms a niche market, probably due to the very sort of format war with rival standard SACD
that DVD-Video
avoided.
mechanism, called Content Protection for Prerecorded Media (CPPM), developed by the 4C group (IBM, Intel, Matsushita, and Toshiba).
Although CPPM was supposed to be much harder to crack than DVD-Video's CSS
, it too was eventually cracked in 2007 with the release of the dvdcpxm tool. The subsequent release of the libdvdcpxm library (which is based on dvdcpxm) allowed for the development of open source DVD-Audio players and ripping software, such as DVD-Audio Explorer
. As a result, making 1:1 copies of DVD-Audio discs is now possible with relative ease, much like DVD-Video discs.
and Blu-ray Disc
were released as the successor to DVD. HD DVD competed unsuccessfully with Blu-ray Disc in the format war
of 2006–2008
. A dual layer HD DVD can store up to 30GB and a dual layer Blu-ray disc can hold up to 50GB.
However, unlike previous format changes, e.g., audio tape 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 70% of video sales and approximately one billion DVD player sales worldwide as of 3 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 as well as the fact of 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. The DVD succeeded because it offered a compelling alternative to VHS. In addition, Blu-ray players are designed to be backward-compatible, allowing older DVDs to be played since the media are physically identical; this differed from the change from vinyl to CD and from tape to DVD, which involved a complete change in physical medium. it is still commonplace for major releases to be issued in "combo pack" format, including both a DVD and a Blu-ray disc (as well as, in many cases, a third disc with an authorized digital copy). Also, some multi-disc sets use Blu-ray for the main feature, but DVDs for supplementary features (examples of this include the Harry Potter
"Ultimate Edition" collections, the 2009 re-release of the 1967 The Prisoner
TV series, and a 2007 collection related to Blade Runner
). Another reason cited (July 2011) for the slower transition to Blu-ray from DVD is the necessity of and confusion over "firmware updates" and needing an internet connection to perform updates.
This situation can be best compared to the changeover from 78 rpm shellac recordings to 45 rpm and 33⅓ rpm vinyl recordings; because the medium used for the earlier format was virtually the same as the latter version (a disc on a turntable, played using a needle), phonographs continued to be built to play obsolete 78s for decades after the format was discontinued. Manufacturers continue to release standard DVD titles , and the format remains the preferred one for the release of older television programs and films, with some programs such as Star Trek: The Original Series
needing to be re-scanned to produce a high definition version from the original film recordings (certain special effects were also updated in order to be better received in high-definition viewing). In the case of Doctor Who
, a series primarily produced on standard definition videotape between 1963 and 1989, BBC Video reportedly intends to continue issuing DVD-format releases of that series until at least November 2013 (since there would be very little increase in visual quality from upconverting the standard definition videotape masters to high definition).
The longevity of the ability to read from a DVD+R or DVD-R is largely dependent on manufacturing quality, ranging from 2 to 15 years, and is believed to be an unreliable medium for backup unless great care is taken for storage conditions and handling.
According to the Optical Storage Technology Association
(OSTA), "manufacturers claim life spans 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".
Optical disc
In computing and optical disc recording technologies, an optical disc is a flat, usually circular disc which encodes binary data in the form of pits and lands on a special material on one of its flat surfaces...
storage
Data storage device
thumb|200px|right|A reel-to-reel tape recorder .The magnetic tape is a data storage medium. The recorder is data storage equipment using a portable medium to store the data....
media format, invented and developed by Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
, Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
, Toshiba
Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
, and Panasonic
Panasonic
Panasonic is an international brand name for Japanese electric products manufacturer Panasonic Corporation, which was formerly known as Matsushita Electric Industrial Co., Ltd...
in 1995. DVDs offer higher storage capacity than Compact Disc
Compact Disc
The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...
s while having the same dimensions.
Pre-recorded DVDs are mass-produced using molding machines
Injection molding machine
An Injection molding machine, also known as an injection press, is a machine for manufacturing plastic products by the injection molding process. It consists of two main parts, an injection unit and a clamping unit....
that physically stamp data onto the DVD. Such discs are known as DVD-ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
, because data can only be read and not written nor erased. Blank recordable DVDs (DVD-R
DVD-R
DVD-R is a DVD recordable format. A DVD-R typically has a storage capacity of 4.71 GB. Pioneer has also developed an 8.5 GB dual layer version, DVD-R DL, which appeared on the market in 2005....
and DVD+R
DVD+R
DVD+R is part of optical disc recording technologies. It is a format for optical disc data storage that utilizes digital recording. It is similar to, but incompatible with, the older DVD-R standard...
) can be recorded once using optical disc recording technologies
Optical disc recording technologies
Optical disc authoring requires a number of different optical disc recorder technologies working in tandem, from the optical disc media to the firmware to the control electronics of the optical disc drive...
and supported by optical disc drives and DVD recorder
DVD recorder
A DVD recorder , is an optical disc recorder that uses Optical disc recording technologies to digitally record analog signal or digital signals onto blank writable DVD media...
s and then function as a DVD-ROM. Rewritable DVDs (DVD-RW
DVD-RW
A DVD-RW disc is a rewritable optical disc with equal storage capacity to a DVD-R, typically 4.7 GB. The format was developed by Pioneer in November 1999 and has been approved by the DVD Forum. The smaller Mini DVD-RW holds 1.46 GB, with a diameter of 8 cm.The primary advantage of DVD-RW over...
, DVD+RW
DVD+RW
DVD+RW is a physical format for rewritable DVDs and can hold up to 4.7 GB. DVD+RW was created by the DVD+RW Alliance, an industry consortium of drive and disc manufacturers...
, and DVD-RAM
DVD-RAM
DVD-RAM is a 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 and personal video recorders since 1998.-Design:DVD-RAM is one of three competing...
) can be recorded and erased multiple times.
DVDs are used in DVD-Video
DVD-Video
DVD-Video is a consumer video format used to store digital video on DVD discs, and is currently the dominant consumer video format in Asia, North America, Europe, and Australia. Discs using the DVD-Video specification require a DVD drive and a MPEG-2 decoder...
consumer digital video format and in DVD-Audio
DVD-Audio
DVD-Audio is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio is not intended to be a video delivery format and is not the same as video DVDs containing concert films or music videos....
consumer digital audio format, as well as for authoring AVCHD discs. DVDs containing other types of information may be referred to as DVD data discs.
History
Before the advent of DVD and Blu-ray, Video CDVideo CD
Before the advent of DVD and Blu-ray, the Video CD became the first format for distributing films on standard 120 mm optical discs. The format is a standard digital format for storing video on a Compact Disc...
(VCD) became the first format for distributing digitally encoded films on standard 120 mm optical discs. (Its predecessor, CD Video
CD Video
CD Video was a format introduced in 1987 that combined the technologies of compact disc and laserdisc. CD-V discs were the same size as a standard 12 cm audio CD, and contained up to 20 minutes worth of audio information that could be played on any audio CD player...
, used analog video encoding.) VCD was on the market in 1993.
In the same year, two new optical disc storage formats were being developed. One was the Multimedia Compact Disc
Compact Disc
The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...
(MMCD), backed by Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
and Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
, and the other was the Super Density (SD) disc, supported by Toshiba
Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
, Time Warner
Time Warner
Time Warner is one of the world's largest media companies, headquartered in the Time Warner Center in New York City. Formerly two separate companies, Warner Communications, Inc...
, Matsushita Electric, Hitachi
Hitachi, Ltd.
is a Japanese multinational conglomerate headquartered in Marunouchi 1-chome, Chiyoda, Tokyo, Japan. The company is the parent of the Hitachi Group as part of the larger DKB Group companies...
, Mitsubishi Electric
Mitsubishi Electric
is a multinational electronics and information technology company headquartered in Tokyo, Japan. It is one of the core companies of the Mitsubishi Group....
, Pioneer
Pioneer Corporation
is a multinational corporation that specializes in digital entertainment products, based in Kawasaki, Kanagawa, Japan. The company was founded in 1938 in Tokyo as a radio and speaker repair shop...
, Thomson
Thomson SA
Technicolor SA , formerly Thomson SA and Thomson Multimedia, is a French international provider of solutions for the creation, management, post-production, delivery and access of video, for the Communication, Media and Entertainment industries. Technicolor’s headquarters are located in Issy les...
, and JVC
JVC
, usually referred to as JVC, is a Japanese international consumer and professional electronics corporation based in Yokohama, Japan which was founded in 1927...
.
Regarding writable media, long before the invention of even CD-R, optical Write Once Read Many
Write Once Read Many
A Write Once Read Many or WORM drive is a data storage device where information, once written, cannot be modified. On ordinary data storage devices, the number of times data can be modified is not limited, except by the rated lifespan of the device, as modification involves physical changes that...
(WORM) drives were used that used 12" disks in a cartridge. These WORM disks used an ablative
Ablation
Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. This occurs in spaceflight during ascent and atmospheric reentry, glaciology, medicine, and passive fire protection.-Spaceflight:...
technology to store data.
Representatives of the SD camp approached IBM, asking for advice on the file system to use for their disc as well as seeking support for their format for storing computer data. Alan E. Bell
Alan E. Bell
Alan E. Bell has worked for many years for notable companies such as Paramount Pictures, Warner Bros. Studios and IBM.His most recent position was as Executive Vice President and Chief Technology Officer for Paramount Pictures....
, a researcher from IBM's Almaden Research Center
Almaden Research Center
The IBM Almaden Research Center is in San Jose, California, and is one of IBM's nine worldwide research labs. Its scientists perform basic and applied research in computer science, services, storage systems, physical sciences, and materials science and technology. The center opened in 1986, and...
got that request and also learned of the MMCD development project. Wary of being caught in a repeat of the costly videotape format war
Videotape format war
The videotape format war was a period of intense competition or "format war" of incompatible models of consumer-level analog video videocassette and video cassette recorders in the late 1970s and the 1980s.- Overview :...
between VHS
VHS
The Video Home System is a consumer-level analog recording videocassette standard developed by Victor Company of Japan ....
and Betamax
Betamax
Betamax was a consumer-level analog videocassette magnetic tape recording format developed by Sony, released on May 10, 1975. The cassettes contain -wide videotape in a design similar to the earlier, professional wide, U-matic format...
in the 1980s, he convened a group of computer industry experts, including representatives from Apple, Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
, Sun
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
, Dell
Dell
Dell, Inc. is an American multinational information technology corporation based in 1 Dell Way, Round Rock, Texas, United States, that develops, sells and supports computers and related products and services. Bearing the name of its founder, Michael Dell, the company is one of the largest...
, and many others. This group was referred to as the Technical Working Group, or TWG.
The TWG voted to boycott both formats unless the two camps agreed on a single, converged standard. Lou Gerstner, president of IBM, was recruited to apply pressure on the executives of the warring factions. Eventually, the computer companies won the day, and a single format, now called DVD, was agreed upon. The TWG also collaborated with the Optical Storage Technology Association
Optical Storage Technology Association
The Optical Storage Technology Association is an international trade association which promotes the use of recordable optical technologies and products, and most notably it is responsible for the creation and maintenance of the UDF specification...
(OSTA) on the use of their implementation of the ISO-13346 file system (known as Universal Disc Format) for use on the new DVDs.
Philips and Sony decided it was in their best interest to avoid another format war over their Multimedia Compact Disc, and agreed to unify with companies backing the Super Density Disc to release a single format with technologies from both. The specification was mostly 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 single-layer but optionally double-sided) and EFMPlus
Eight-to-Fourteen Modulation
Eight-to-fourteen modulation is a data encoding technique – formally, a channel code – used by compact discs and pre-Hi-MD MiniDiscs. EFMPlus is a related code, used in DVDs and SACDs. EFM and EFMPlus were both invented by Kees A...
modulation.
EFMPlus was chosen because of its great resilience to disc damage, such as scratches and fingerprints. EFMPlus, created by Kees Immink
Kees A. Schouhamer Immink
Kornelis Antonie Schouhamer Immink is a Dutch scientist, inventor, and entrepreneur, who pioneered and advanced the era of digital audio, video, and data recording including popular digital media such as Compact Disc, DVD and Blu-Ray Disc. He has been a prolific and influential engineer, who...
(who also designed EFM
Eight-to-Fourteen Modulation
Eight-to-fourteen modulation is a data encoding technique – formally, a channel code – used by compact discs and pre-Hi-MD MiniDiscs. EFMPlus is a related code, used in DVDs and SACDs. EFM and EFMPlus were both invented by Kees A...
), is 6% less efficient than the modulation technique originally used by Toshiba, which resulted in a capacity of 4.7 GB, as opposed to the original 5 GB. The result was the DVD specification, finalized for the DVD movie player and DVD-ROM computer applications in December 1995.
The DVD Video format was first introduced by Toshiba in Japan in November 1996, in the United States in March 1997 (test marketed), in Europe in October 1998, and in Australia in February 1999.
In May 1997, the DVD Consortium was replaced by the DVD Forum
DVD Forum
The DVD Forum is an international organization composed of hardware, software, media and content companies that use and develop the DVD and formerly HD DVD formats...
, which is open to all other companies.
Specifications
DVD specifications created and updated by the DVD ForumDVD Forum
The DVD Forum is an international organization composed of hardware, software, media and content companies that use and develop the DVD and formerly HD DVD formats...
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 Book, DVD-VR
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 not DVD-Video compliant, and will not play back in...
Book, etc.).
Some specifications for mechanical, physical and optical characteristics of DVD optical discs can be downloaded as freely available standards from the ISO website. Also, the DVD+RW Alliance
DVD+RW Alliance
The DVD+RW Alliance is a group of electronic hardware, optical storage and software manufacturers who in 1997 created and promoted a format standard of recordable and rewritable DVDs, known as the "plus" format. As of 2004, plus format DVDs were available in three forms: DVD+R, DVD+RW, and DVD+R...
publishes competing DVD specifications such as DVD+R, DVD+R DL, DVD+RW or DVD+RW DL. These DVD formats are also ISO standards.
Some of DVD specifications (e.g. for DVD-Video) are not publicly available and can be obtained only from the DVD Format/Logo Licensing Corporation for a fee of US $5000. Every subscriber must sign a non-disclosure agreement
Non-disclosure agreement
A non-disclosure agreement , also known as a confidentiality agreement , confidential disclosure agreement , proprietary information agreement , or secrecy agreement, is a legal contract between at least two parties that outlines confidential material, knowledge, or information that the parties...
as certain information in the DVD Book is proprietary and confidential.
Etymology
The official DVD charter documents specify that the basis of the DVD name stems from the term digital versatile disc. Usage in the present day varies, with Digital Versatile Disc, Digital Video Disc, and DVD being the most common.DVD was originally used as an initialism for the unofficial term
digital videodisc.
A newsgroup FAQ
FAQ
Frequently asked questions are listed questions and answers, all supposed to be commonly asked in some context, and pertaining to a particular topic. "FAQ" is usually pronounced as an initialism rather than an acronym, but an acronym form does exist. Since the acronym FAQ originated in textual...
written by Jim Taylor (a prominent figure in the industry) claims that four years later, in 1999, the DVD Forum stated that the format name was simply the three letters "DVD" and did not stand for anything.
The DVD Forum
DVD Forum
The DVD Forum is an international organization composed of hardware, software, media and content companies that use and develop the DVD and formerly HD DVD formats...
website has a section called "DVD Primer" in which the answer to the question, "What does DVD mean?" reads, "The keyword is 'versatile.' Digital Versatile Discs provide superb video, audio and data storage and access—all on one disc."
Identification (MID)
The DVD is made of a spiral groove read or written starting at the center. The form of the groove encodes unalterable identification data known as Media Identification CodeMedia Identification Code
The Media IDentification code is used on DVD-R, DVD+R and DVD-RAM discs to identify the manufacturer and to assist the DVD burner to select the best write strategy for the inserted media...
(MID). The MID contains pre-recorded information as to who really manufactures the disc, under a certain brand name that the consumer is more familiar with. Also included is the byte capacity and permitted burning speeds (dependent on both the recorder, or burner, as well as what the disc can handle). This information can be read on many disc authoring software, such as ImgBurn.
A MID code is generally seen to be more reassuring for individuals whose priority is the long term storage of their data than just a buying for brand name sake. However, not all MID codes are produced in the same way. For example internet club Club MyCE specialises in disc burning consensually swear that anything not produced by Japanese disc manufacturers Verbatim or Taiyo Yuden will be of inferior burning quality and offer lower longtivity than people who burn Verbatim or Taiyo Yuden discs.
This is for many reasons. Verbatim and Taiyo Yuden have high quality standards to ensure their discs are excellent, (and anything that fails their strict quality regulation often gets destroyed) whilst other famous disc manufacturers, such as CMC Magnetics Corporation or Ritek Corporation tend to produce to vary per batch, resulting in inconsistency and poor burning results. Another reason is the burner's firmware; a set of instructions varying from burner to burner as to how to interact with the disc. They determine how well a burn will be, or even if it will finish at all. A burn that fails to record during burning, or verifying, is referred to as a "coaster" - or an unusable disc. Several errors as such may be encountered when trying to play back the disc.
Additionally, it is the firmware that determines how well it supports the MID code. Samsung and BenQ burners for example tend to be more tolerant of less well known MID codes, whilst a LG and a Matsushita burner (made by parent company Panasonic) might be a little pickier over what it can handle.
As a result, many disc producers have turned to "faking" mid codes in order to obtain better firmware support. UmeDisc, who produce discs on behalf of AOne, Tesco, Signellex, etc. may turn to faking a Taiyo Yuden MID or a Mitsubishi MKM MID (manufacturer for Verbatim) so the burner can interpret it better. An AOne 8x DVD-R disc uses a Taiyo Yuden MID, (TYG02) although its real MID code should be UME01.
The cheaper brand of discs may turn to "outsourcing" their products. This is where a brand name of disc changes the manufacturer depending on who on will sell them a batch of discs at the lowest price. Memorex is quite famous for changing their manufacturers on a regular occasion, (one spindle of DVD blanks may be produced by one manufacturer whilst another spindle may be produced by another). Brands who outsource tend to obtain the lowest quality batch of spindle, and thus makes them inconsistent for long term, let alone for burning.
However, some brands of discs remain loyal to their supplier. Traxdata and Arita are Ritek-only brands, whilst Datasafe and Datawrite are firm with CMC Magnetics.
Design
As a movie delivery medium
DVD was adopted by movie and home entertainment distributors to replace the ubiquitous VHS tape as the primary means of distributing films to consumers in the home entertainment marketplace. DVD was chosen for its superior ability to reproduce moving pictures and sound, for its superior durability, and for its interactivity. Interactivity had proven to be a feature which consumers, especially collectors, favored when the movie studios had released their films on LaserDiscLaserdisc
LaserDisc was a home video format and the first commercial optical disc storage medium. Initially licensed, sold, and marketed as MCA DiscoVision in North America in 1978, the technology was previously referred to interally as Optical Videodisc System, Reflective Optical Videodisc, Laser Optical...
. When the price point for a LaserDisc at approximately $100 per disc moved to $20 per disc at retail, this luxury feature became available for mass consumption. Simultaneously, the movie studios decided to change their home entertainment release model from a rental model to a for purchase model, and large numbers of DVDs were sold.
At the same time, a demand for interactive design talent and services was created. Movies in the past had uniquely designed title sequences. Suddenly every movie being released required information architecture and interactive design components that matched the film's tone and were at the quality level that Hollywood demanded for its product.
As an interactive medium
DVD as a format had two qualities at the time that were not available in any other interactive medium: 1. Enough capacity and speed to provide high quality, full motion video and sound, and 2. low cost delivery mechanism provided by consumer products retailers who quickly moved to sell their players for under $200 and eventually for under $50 at retail. In addition, the medium itself was small enough and light enough to mail using general first class postage. Almost overnight, this created a new business opportunity and model for business innovators like Netflix to re-invent the home entertainment distribution model. It also opened up the opportunity for business and product information to be inexpensively provided on full motion video through direct mail.Capacity
| Designation | Sides | Layers (total) | Diameter (cm) | Capacity | ||
|---|---|---|---|---|---|---|
| (GB Gigabyte The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is... ) | | (GiB Gibibyte The gibibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The gibibyte unit symbol is GiB.... ) |
|||||
| DVD-1 | SS SL | 1 | 1 | 8 | 1.46 | 1.36 |
| DVD-2 | SS DL | 1 | 2 | 8 | 2.66 | 2.47 |
| DVD-3 | DS SL | 2 | 2 | 8 | 2.92 | 2.72 |
| DVD-4 | DS DL | 2 | 4 | 8 | 5.32 | 4.95 |
| DVD-5 | SS SL | 1 | 1 | 12 | 4.70 | 4.37 |
| DVD-9 | SS DL | 1 | 2 | 12 | 8.54 | 7.95 |
| DVD-10 | DS SL | 2 | 2 | 12 | 9.40 | 8.75 |
| DVD-14 | DS SL+DL | 2 | 3 | 12 | 13.24 | 12.33 |
| DVD-18 | DS DL | 2 | 4 | 12 | 17.08 | 15.90 |
| Designation | Sides | Layers (total) | Diameter (cm) | Capacity | ||
|---|---|---|---|---|---|---|
| (GB Gigabyte The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is... ) | | (GiB Gibibyte The gibibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The gibibyte unit symbol is GiB.... ) |
|||||
| DVD-R | SS SL (1.0) | 1 | 1 | 12 | 3.95 | 3.68 |
| DVD-R | SS SL (2.0) | 1 | 1 | 12 | 4.70 | 4.37 |
| DVD-RW | SS SL | 1 | 1 | 12 | 4.70 | 4.37 |
| DVD+R | SS SL | 1 | 1 | 12 | 4.70 | 4.37 |
| DVD+RW | SS SL | 1 | 1 | 12 | 4.70 | 4.37 |
| DVD-R | DS SL | 2 | 2 | 12 | 9.40 | 8.75 |
| DVD-RW | DS SL | 2 | 2 | 12 | 9.40 | 8.75 |
| DVD+R | DS SL | 2 | 2 | 12 | 9.40 | 8.75 |
| DVD+RW | DS SL | 2 | 2 | 12 | 9.40 | 8.75 |
| DVD-RAM | SS SL | 1 | 1 | 8 | 1.46 | 1.36* |
| DVD-RAM | DS SL | 2 | 2 | 8 | 2.65 | 2.47* |
| DVD-RAM | SS SL (1.0) | 1 | 1 | 12 | 2.58 | 2.40 |
| DVD-RAM | SS SL (2.0) | 1 | 1 | 12 | 4.70 | 4.37 |
| DVD-RAM | DS SL (1.0) | 2 | 2 | 12 | 5.16 | 4.80 |
| DVD-RAM | DS SL (2.0) | 2 | 2 | 12 | 9.40 | 8.75* |
The basic types of DVD (12 cm diameter, single-sided or homogeneous double-sided) are referred to by a rough approximation of their capacity in gigabytes. In draft versions of the specification, DVD-5 indeed held five gigabytes, but some parameters were changed later on as explained above, so the capacity decreased. Other formats
DVD formats
-Non-recordable formats:*DVD-ROM: These are pressed similarly to CDs. The reflective surface is silver or gold colored. They can be single-sided/single-layered, single-sided/double-layered, double-sided/single-layered, or double-sided/double-layered. As of 2004, new double-sided discs have become...
, those with 8 cm diameter and hybrid variants, acquired similar numeric names with even larger deviation.
The 12 cm type is a standard DVD, and the 8 cm variety is known as a MiniDVD
MiniDVD
MiniDVD is a DVD disc having 8 cm in diameter.The 8 cm optical disc format was originally used for music CD singles, hence the commonly used names CD single and miniCD...
. These are the same sizes as a standard CD and a mini-CD
Mini CD
Mini CDs, or “pocket CDs” are CDs with a smaller diameter and one third the capacity.-Formats:Amongst the various formats are the* Mini CD single, a small disc. The format is mainly used for audio CD singles in certain regions , much like the old vinyl single...
, respectively. The capacity by surface (MiB/cm2) varies from 6.92 MiB/cm2 in the DVD-1 to 18.0 MiB/cm2 in the DVD-18.
As with hard disk drives, in the DVD realm, gigabyte
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...
and the symbol GB are usually used in the SI
Si
Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...
sense (i.e., 109, or 1,000,000,000 bytes). For distinction, gibibyte
Gibibyte
The gibibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The gibibyte unit symbol is GiB....
(with symbol GiB) is used (i.e., 10243 (230), or 1,073,741,824 bytes).
| Type | Sectors | Bytes | kB Kilobyte The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information... |
MB Megabyte The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000... |
GB Gigabyte The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is... |
KiB Kibibyte The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission in 1999 and has been accepted for use... |
MiB Mebibyte The mebibyte is a multiple of the unit byte for digital information. The binary prefix mebi means 220, therefore 1 mebibyte is . The unit symbol for the mebibyte is MiB. The unit was established by the International Electrotechnical Commission in 2000 and has been accepted for use by all major... |
GiB Gibibyte The gibibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The gibibyte unit symbol is GiB.... |
|---|---|---|---|---|---|---|---|---|
| DVD-R SL | 2,298,496 | 4,707,319,808 | 4,707,319.808 | 4,707.320 | 4.707 | 4,596,992 | 4,489.250 | 4.384 |
| DVD+R SL | 2,295,104 | 4,700,372,992 | 4,700,372.992 | 4,700.373 | 4.700 | 4,590,208 | 4,482.625 | 4.378 |
| DVD-R DL | 4,171,712 | 8,543,666,176 | 8,543,666.176 | 8,543.666 | 8.544 | 8,343,424 | 8,147.875 | 7.957 |
| DVD+R DL | 4,173,824 | 8,547,991,552 | 8,547,991.552 | 8,547.992 | 8.548 | 8,347,648 | 8,152.000 | 7.961 |
Technology
Laser diode
The laser diode is a laser where the active medium is a semiconductor similar to that found in a light-emitting diode. The most common type of laser diode is formed from a p-n junction and powered by injected electric current...
light as opposed to 780 nm for CD. This permits a smaller pit to be etched on the media surface compared to CDs (0.74 µm for DVD versus 1.6 µm for CD), allowing in part for DVD's increased storage capacity.
In comparison, Blu-ray Disc
Blu-ray Disc
Blu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...
, the successor to the DVD format, uses a wavelength of 405 nm, and one dual-layer disc has a 50 GB storage capacity.
Writing speeds for DVD were 1×, that is, 1,385 kB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
/s (1,353 KiB
Kibibyte
The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission in 1999 and has been accepted for use...
/s), in the first drives and media models. 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.
| Drive speed | Data rate | ~Write time (min) | |||
|---|---|---|---|---|---|
| (Mbit/s) | (MB/s) | (MiB/s) | SL | DL | |
| 1× | 11.08 | 1.39 | 1.32 | 57 | 103 |
| 2× | 22.16 | 2.77 | 2.64 | 28 | 51 |
| 2.4× | 26.59 | 3.32 | 3.17 | 24 | 43 |
| 2.6× | 28.81 | 3.60 | 3.43 | 22 | 40 |
| 4× | 44.32 | 5.54 | 5.28 | 14 | 26 |
| 6× | 66.48 | 8.31 | 7.93 | 9 | 17 |
| 8× | 88.64 | 11.08 | 10.57 | 7 | 13 |
| 10× | 110.80 | 13.85 | 13.21 | 6 | 10 |
| 12× | 132.96 | 16.62 | 15.85 | 5 | 9 |
| 16× | 177.28 | 22.16 | 21.13 | 4 | 6 |
| 18× | 199.44 | 24.93 | 23.78 | 3 | 6 |
| 20× | 221.60 | 27.70 | 26.42 | 3 | 5 |
| 22× | 243.76 | 30.47 | 29.06 | 3 | 5 |
| 24× | 265.92 | 33.24 | 31.70 | 2 | 4 |
Internal mechanism of a drive
With reference to the photo, just to the right of image center is the disc spin motor, a gray cylinder, with its gray centering hub and black resilient drive ring on top. A clamp (not in the photo, retained in the drive's cover), pulled down by a magnet, clamps the disc when this mechanism rises, after the disc tray stops moving inward. This motor has an external rotor – every visible part of it spins.
The gray metal chassis is shock-mounted at its four corners to reduce sensitivity to external shocks, and to reduce drive noise when running fast. The soft shock mount grommets are just below the brass-colored washers at the four corners (the left one is obscured). Running through those grommets are screws to fasten them to the black plastic frame that's underneath.
Two parallel precision guide rods that run between upper left and lower right in the photo carry the "sled
Sled
A sled, sledge, or sleigh is a land vehicle with a smooth underside or possessing a separate body supported by two or more smooth, relatively narrow, longitudinal runners that travels by sliding across a surface. Most sleds are used on surfaces with low friction, such as snow or ice. In some cases,...
", the moving optical read-write head. As shown, this "sled" is close to, or at the position where it reads or writes at the edge of the disc.
A dark gray disc with two holes on opposite sides has a blue lens surrounded by silver-colored metal. This is the lens that's closest to the disc; it serves to both read and write by focusing the laser light to a very small spot. It is likely that this disc rotates half a turn to position a different set of optics (the other "hole") for CDs vs. DVDs.
Under the disc is an ingenious actuator comprising permanent magnets and coils that move the lens up and down to maintain focus on the data layer. As well, the actuator moves the lens slightly toward and away from the spin-motor spindle to keep the spot on track. Both focus and tracking are relatively quite fast and very precise. The same actuator rotates the lens mount half a turn as described.
To select tracks (or files) as well as advancing the "sled" during continuous read or write operations, a stepping motor rotates a coarse-pitch leadscrew to move the "sled" throughout its total travel range. The motor, itself, is the gray cylinder just to the left of the most-distant shock mount; its shaft is parallel to the support rods. The leadscrew, itself, is the rod with evenly-spaced darker details; these are the helical groove that engages a pin on the "sled".
The irregular orange material is flexible etched copper foil supported by thin sheet plastic; these are "flexible printed circuits" that connect everything to the electronics (which is not shown).
DVD recordable and rewritable
HPHewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
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
DVD-R
DVD-R is a DVD recordable format. A DVD-R typically has a storage capacity of 4.71 GB. Pioneer has also developed an 8.5 GB dual layer version, DVD-R DL, which appeared on the market in 2005....
/RW
DVD-RW
A DVD-RW disc is a rewritable optical disc with equal storage capacity to a DVD-R, typically 4.7 GB. The format was developed by Pioneer in November 1999 and has been approved by the DVD Forum. The smaller Mini DVD-RW holds 1.46 GB, with a diameter of 8 cm.The primary advantage of DVD-RW over...
, DVD+R
DVD+R
DVD+R is part of optical disc recording technologies. It is a format for optical disc data storage that utilizes digital recording. It is similar to, but incompatible with, the older DVD-R standard...
/RW
DVD+RW
DVD+RW is a physical format for rewritable DVDs and can hold up to 4.7 GB. DVD+RW was created by the DVD+RW Alliance, an industry consortium of drive and disc manufacturers...
(plus), and DVD-RAM
DVD-RAM
DVD-RAM is a 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 and personal video recorders since 1998.-Design:DVD-RAM is one of three competing...
. DVD-R is available in two formats, General (650 nm) and Authoring (635 nm), where Authoring discs may be recorded with encrypted content but General discs may not.
Although most DVD writers can nowadays write the DVD+R/RW and DVD-R/RW formats (usually denoted by "DVD±RW" and/or the existence of both the DVD Forum logo and the DVD+RW Alliance logo), the "plus" and the "dash" formats use different writing specifications. Most DVD readers and players will play both kinds of discs, although older models can have trouble with the "plus" variants.
Some first generation DVD player
DVD player
A DVD player is a device that plays discs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. These devices were invented in 1997 and continue to thrive...
s would cause damage to DVD±R/RW/DL when attempting to read them.
Dual-layer recording
Dual-layer recording (sometimes also known as double-layer recording) allows DVD-RDVD-R
DVD-R is a DVD recordable format. A DVD-R typically has a storage capacity of 4.71 GB. Pioneer has also developed an 8.5 GB dual layer version, DVD-R DL, which appeared on the market in 2005....
and DVD+R
DVD+R
DVD+R is part of optical disc recording technologies. It is a format for optical disc data storage that utilizes digital recording. It is similar to, but incompatible with, the older DVD-R standard...
discs to store significantly more data—up to 8.54 gigabyte
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...
s per disc, compared with 4.7 gigabytes for single-layer discs. Along with this, DVD-DLs have slower write speeds as compared to ordinary DVDs and when played on a DVD player a slight transition can sometimes be seen between the layers. DVD-R DL
DVD-R DL
DVD-R DL , also called DVD-R9, is a derivative of the DVD-R format standard. DVD-R DL discs hold 8.54 GB per side by utilizing two recordable dye layers, each capable of storing nearly the 4.7 gigabyte of a single layer disc -almost doubling the total disc capacity...
was developed for the DVD Forum by Pioneer Corporation
Pioneer Corporation
is a multinational corporation that specializes in digital entertainment products, based in Kawasaki, Kanagawa, Japan. The company was founded in 1938 in Tokyo as a radio and speaker repair shop...
; DVD+R DL
DVD+R DL
DVD+R DL 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 storing nearly the 4.7 GB capacity of a single-layer disc, almost doubling the total...
was developed for the DVD+RW Alliance by Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
and Mitsubishi Kagaku Media (MKM).
A dual-layer disc differs from its usual DVD counterpart by employing a second physical layer within the disc itself. The drive with dual-layer capability accesses the second layer by shining the laser through the first semitransparent layer. In some DVD players, the layer change can exhibit a noticeable pause, up to several seconds. This caused some viewers to worry that their dual-layer discs were damaged or defective, with the end result that studios began listing a standard message explaining the dual-layer pausing effect on all dual-layer disc packaging.
DVD recordable discs supporting this technology are backward-compatible with some existing DVD players and DVD-ROM drives. Many current DVD recorder
DVD recorder
A DVD recorder , is an optical disc recorder that uses Optical disc recording technologies to digitally record analog signal or digital signals onto blank writable DVD media...
s support dual-layer technology, and the price is now comparable to that of single-layer drives, although the blank media remain more expensive. The recording speeds reached by dual-layer media are still well below those of single-layer media. A potential reason is how Dual Layer discs are not as well matured compared to the Single Layer discs, as well as consumers, on a whole, have no desire for increased burning speeds.
There are two modes for dual-layer orientation. With Parallel Track Path (PTP), used on DVD-ROM, both layers start at the inside diameter (ID) and end at the outside diameter (OD) with the lead-out. With Opposite Track Path
Opposite Track Path
Opposite Track Path is a term used in optical DVD technology, allowing fast switching from layer 0 to layer 1.A dual-layer DVD with Opposite Track Path means that layer 0 is written in a spiral track starting at the inside of the disc, whereas the layer 1 spiral starts at the outside of the disc...
(OTP), used on many Digital Video Discs, the lower layer starts at the ID and the upper layer starts at the OD, where the other layer ends; they share one lead-in and one lead-out.
DVD-Video
DVD-Video is a standard for storing and distributing video/audio content on DVD media. The format went on sale in Japan in 1996, in the United States in 1997, in Europe in 1998 and in Australia in 1999. DVD-Video became the dominant form of home video distribution in Japan when it first went on sale in 1996, but did not become the dominant form of home video distribution in the United States until June 15, 2003, when weekly DVD-Video in the United States rentals began outnumbering weekly VHS cassette rentals, reflecting the rapid adoption rate of the technology in the U.S. marketplace.Currently, DVD-Video is the dominant form of home video distribution worldwide, although in Japan it was surpassed by Blu-ray Disc
Blu-ray Disc
Blu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...
when Blu-ray first went on sale in Japan on March 31, 2006.
Security
Content Scramble System (CSS) is a Digital Rights ManagementDigital rights management
Digital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...
(DRM) and encryption
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
system employed on almost all commercially produced DVD-video discs. CSS utilizes a proprietary 40-bit stream cipher
Stream cipher
In cryptography, a stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream . In a stream cipher the plaintext digits are encrypted one at a time, and the transformation of successive digits varies during the encryption...
algorithm. The system was introduced around 1996 and was first compromised in 1999.
The purpose of CSS is twofold:
- CSS prevents byte-for-byte copies of an MPEG (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 codeDVD region codeDVD region codes are a digital-rights management technique designed to allow film distributors to control aspects of a release, including content, release date, and price, according to the region...
s, MacrovisionMacrovisionRovi Corporation is a globally operating, US-based company that provides guidance technology, entertainment data, copy protection, industry standard networking and media management technology for digital entertainment devices and services...
, and user operation prohibitionUser operation prohibitionThe user operation prohibition 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 that are protected or restricted by this feature, and will display...
) be implemented.
While most CSS-decrypting software is used to play DVD videos, other pieces of software (such as DVD Decrypter
DVD Decrypter
DVD Decrypter is a software application for Microsoft Windows that can create backup disk images of the DVD-Video structure of DVDs. It can be used to image any DVD, but controversially it is especially useful for decrypting copy protected movies. The program can also record images to disc...
, AnyDVD
AnyDVD
AnyDVD is a Microsoft Windows driver allowing decryption of DVDs on-the-fly, as well as targeted removal of copy preventions and user operation prohibitions . With an upgrade, it will also do the same for HD DVD and Blu-ray. The AnyDVD program runs in the background, making discs unrestricted and...
, DVD43
DVD43
DVD43 is a free DVD driver for 32 bit versions of Windows. As the user guide states, "DVD43 stands for "DVD For Free". It acts as a driver for optical drives, disabling zone and copy protection information. It assists in the creation of backup copies of DVDs one legally owns and the use of DVDs...
, Smartripper, and DVD Shrink
DVD Shrink
DVD Shrink is a freeware DVD transcoder program for Microsoft Windows that uses a DVD ripper to back up DVD movies. The final versions are 3.2.0.15 and 3.2.0.16 ; all other versions, such as DVD Shrink 2010, are scams...
) can copy a DVD to a hard drive and remove Macrovision
Macrovision
Rovi Corporation is a globally operating, US-based company that provides guidance technology, entertainment data, copy protection, industry standard networking and media management technology for digital entertainment devices and services...
, CSS encryption, region codes
DVD region code
DVD region codes are a digital-rights management technique designed to allow film distributors to control aspects of a release, including content, release date, and price, according to the region...
and user operation prohibition
User operation prohibition
The user operation prohibition 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 that are protected or restricted by this feature, and will display...
.
Consumer restrictions
The rise of filesharing and "piracyCopyright infringement
Copyright infringement is the unauthorized or prohibited use of works under copyright, infringing the copyright holder's exclusive rights, such as the right to reproduce or perform the copyrighted work, or to make derivative works.- "Piracy" :...
" has prompted many copyright holders to display notices on DVD packaging or displayed on screen when the content is played that warn consumers of the illegality of certain uses of the DVD. It is commonplace to include a 90 second advert warning that most forms of copying the contents are illegal. Many DVDs prevent skipping past or fast-forwarding through this warning.
Arrangements for renting and lending differ by geography. In the U.S., the right to re-sell, rent, or lend out bought DVDs is protected by the first-sale doctrine
First-sale doctrine
The first-sale doctrine is a limitation on copyright that was recognized by the Supreme Court of the United States in 1908 and subsequently codified in the Copyright Act of 1976,...
under the Copyright Act of 1976
Copyright Act of 1976
The Copyright Act of 1976 is a United States copyright law and remains the primary basis of copyright law in the United States, as amended by several later enacted copyright provisions...
. In Europe, rental and lending rights are more limited, under a 1992 European Directive that gives copyright holders broader powers to restrict the commercial renting and public lending of DVD copies of their work.
DVD-Audio
DVD-Audio is a format for delivering high fidelity audio content on a DVD. It offers many channel configuration options (from monoMonaural
Monaural or monophonic sound reproduction is single-channel. Typically there is only one microphone, one loudspeaker, or channels are fed from a common signal path...
to 5.1 surround sound
5.1 surround sound
5.1 is the common name for six channel surround sound multichannel audio systems. 5.1 is now the most commonly used layout in both commercial cinemas and home theaters. It uses five full bandwidth channels and one low frequency enhancement channel . Dolby Digital, Dolby Pro Logic II, DTS, and...
) at various sampling frequencies (up to 24-bits/192 kHz versus CDDA's 16-bits/44.1 kHz). Compared with the CD format, the much higher-capacity DVD format enables the inclusion of considerably more music (with respect to total running time and quantity of songs) and/or far higher audio quality (reflected by higher sampling rate
Sampling rate
The sampling rate, sample rate, or sampling frequency defines the number of samples per unit of time taken from a continuous signal to make a discrete signal. For time-domain signals, the unit for sampling rate is hertz , sometimes noted as Sa/s...
s and greater sample resolution, and/or additional channels for spatial sound reproduction).
Despite DVD-Audio's superior technical specifications, there is debate as to whether the resulting audio enhancements are distinguishable in typical listening environments. DVD-Audio currently forms a niche market, probably due to the very sort of format war with rival standard SACD
Super Audio CD
Super Audio CD is a high-resolution, read-only optical disc for audio storage. Sony and Philips Electronics jointly developed the technology, and publicized it in 1999. It is designated as the Scarlet Book standard. Sony and Philips previously collaborated to define the Compact Disc standard...
that DVD-Video
DVD-Video
DVD-Video is a consumer video format used to store digital video on DVD discs, and is currently the dominant consumer video format in Asia, North America, Europe, and Australia. Discs using the DVD-Video specification require a DVD drive and a MPEG-2 decoder...
avoided.
Security
DVD-Audio discs employ a DRMDigital rights management
Digital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...
mechanism, called Content Protection for Prerecorded Media (CPPM), developed by the 4C group (IBM, Intel, Matsushita, and Toshiba).
Although CPPM was supposed to be much harder to crack than DVD-Video's CSS
Content Scramble System
Content Scramble System is a Digital Rights Management and encryption system employed on almost all commercially produced DVD-Video discs. CSS utilizes a proprietary 40-bit stream cipher algorithm...
, it too was eventually cracked in 2007 with the release of the dvdcpxm tool. The subsequent release of the libdvdcpxm library (which is based on dvdcpxm) allowed for the development of open source DVD-Audio players and ripping software, such as DVD-Audio Explorer
DVD-Audio Explorer
DVD-Audio Explorer is a software application for extracting audio tracks off a DVD-Audio disc and save them to a computer. The program also supports saving tracks to stereo and multichannel wav format...
. As a result, making 1:1 copies of DVD-Audio discs is now possible with relative ease, much like DVD-Video discs.
Blu-ray Disc
In 2006, two new formats called HD DVDHD DVD
HD DVD is a discontinued high-density optical disc format for storing data and high-definition video.Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format...
and Blu-ray Disc
Blu-ray Disc
Blu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...
were released as the successor to DVD. HD DVD competed unsuccessfully with Blu-ray Disc in the format war
Format war
A format war describes competition between mutually incompatible proprietary formats that compete for the same market, typically for data storage devices and recording formats for electronic media. It is often characterized by political and financial influence on content publishers by the...
of 2006–2008
High definition optical disc format war
A format war took place between the Blu-ray Disc and HD DVD optical disc standards for storing high definition video and audio.These standards emerged between 2000 and 2002 and attracted both the mutual and exclusive support of major consumer electronics manufacturers, personal computer...
. A dual layer HD DVD can store up to 30GB and a dual layer Blu-ray disc can hold up to 50GB.
However, unlike previous format changes, e.g., audio tape 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 70% of video sales and approximately one billion DVD player sales worldwide as of 3 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 as well as the fact of 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. The DVD succeeded because it offered a compelling alternative to VHS. In addition, Blu-ray players are designed to be backward-compatible, allowing older DVDs to be played since the media are physically identical; this differed from the change from vinyl to CD and from tape to DVD, which involved a complete change in physical medium. it is still commonplace for major releases to be issued in "combo pack" format, including both a DVD and a Blu-ray disc (as well as, in many cases, a third disc with an authorized digital copy). Also, some multi-disc sets use Blu-ray for the main feature, but DVDs for supplementary features (examples of this include the Harry Potter
Harry Potter
Harry Potter is a series of seven fantasy novels written by the British author J. K. Rowling. The books chronicle the adventures of the adolescent wizard Harry Potter and his best friends Ron Weasley and Hermione Granger, all of whom are students at Hogwarts School of Witchcraft and Wizardry...
"Ultimate Edition" collections, the 2009 re-release of the 1967 The Prisoner
The Prisoner
The Prisoner is a 17-episode British television series first broadcast in the UK from 29 September 1967 to 1 February 1968. Starring and co-created by Patrick McGoohan, it combined spy fiction with elements of science fiction, allegory and psychological drama.The series follows a British former...
TV series, and a 2007 collection related to Blade Runner
Blade Runner
Blade Runner is a 1982 American science fiction film directed by Ridley Scott and starring Harrison Ford, Rutger Hauer, and Sean Young. The screenplay, written by Hampton Fancher and David Peoples, is loosely based on the novel Do Androids Dream of Electric Sheep? by Philip K...
). Another reason cited (July 2011) for the slower transition to Blu-ray from DVD is the necessity of and confusion over "firmware updates" and needing an internet connection to perform updates.
This situation can be best compared to the changeover from 78 rpm shellac recordings to 45 rpm and 33⅓ rpm vinyl recordings; because the medium used for the earlier format was virtually the same as the latter version (a disc on a turntable, played using a needle), phonographs continued to be built to play obsolete 78s for decades after the format was discontinued. Manufacturers continue to release standard DVD titles , and the format remains the preferred one for the release of older television programs and films, with some programs such as Star Trek: The Original Series
Star Trek: The Original Series
Star Trek is an American science fiction television series created by Gene Roddenberry, produced by Desilu Productions . Star Trek was telecast on NBC from September 8, 1966, through June 3, 1969...
needing to be re-scanned to produce a high definition version from the original film recordings (certain special effects were also updated in order to be better received in high-definition viewing). In the case of Doctor Who
Doctor Who
Doctor Who is a British science fiction television programme produced by the BBC. The programme depicts the adventures of a time-travelling humanoid alien known as the Doctor who explores the universe in a sentient time machine called the TARDIS that flies through time and space, whose exterior...
, a series primarily produced on standard definition videotape between 1963 and 1989, BBC Video reportedly intends to continue issuing DVD-format releases of that series until at least November 2013 (since there would be very little increase in visual quality from upconverting the standard definition videotape masters to high definition).
Use as backup medium
Durability of DVDs is measured by how long the data may be read from the disc, assuming compatible devices exist that can read it: that is, how long the disc can be stored until data is lost. Five factors affect durability: sealing method, reflective layer, organic dye makeup, where it was manufactured, and storage practices.The longevity of the ability to read from a DVD+R or DVD-R is largely dependent on manufacturing quality, ranging from 2 to 15 years, and is believed to be an unreliable medium for backup unless great care is taken for storage conditions and handling.
According to the Optical Storage Technology Association
Optical Storage Technology Association
The Optical Storage Technology Association is an international trade association which promotes the use of recordable optical technologies and products, and most notably it is responsible for the creation and maintenance of the UDF specification...
(OSTA), "manufacturers claim life spans 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".
See also
- Book typeBook typeThe book type is a field of four bits at the start of every DVD that indicates what the physical format of the disc is...
- Digital video recorderDigital video recorderA digital video recorder , sometimes referred to by the merchandising term personal video recorder , is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device...
(DVR) - Disk drive performance characteristics
- DVD authoringDVD authoringDVD 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 group in 1995...
- DVD ripperDVD ripperA DVD ripper is a software program that facilitates copying the content of a DVD to a hard disk drive. They are mainly used to transfer video on DVDs to different formats, to edit or back up DVD content, and to convert DVD video for playback on media players and mobile devices...
- DVD region codeDVD region codeDVD region codes are a digital-rights management technique designed to allow film distributors to control aspects of a release, including content, release date, and price, according to the region...
- DVD TV gameDVD TV gameA DVD TV game is a standalone game that can be played on a set-top DVD player. The game takes advantage of technology built into the DVD format to create an interactive gaming environment compatible with most DVD players without requiring additional hardware...
- EvitaEvita (film)Evita is the 1996 film adaptation of Tim Rice and Andrew Lloyd Webber's musical of the same name based on the life of Eva Perón. It was directed by Alan Parker and written by Parker and Oliver Stone. It starred Madonna, Antonio Banderas, and Jonathan Pryce...
(first film to be released on DVD) - FlexplayFlexplayFlexplay is a trademark for a DVD-compatible optical video disc format with a time-limited playback time. They are often described as "self-destructing" although the disc merely turns black and does not physically disintegrate. The same technology was used by Disney's Buena Vista Home...
disposable discs - IFOIFOIFO is a type of DVD-Video file that stores information about chapters, subtitles and audio tracks.An IFO file is one of three types of files that are used on DVDs. It contains important navigational information, such as where a video chapter begins, and where audio and subtitle streams exist...
, BUPBUPA BUP file is a backup of the IFO file on a DVD, which contains the information about the organization of tracks, menus, chapters, subtitles on the disc. BUP files are used in the event that the corresponding IFO file is unreadable, perhaps due to a scratch on the surface of the disc.Other DVD...
and VOBVOBA VOB file is a container format in DVD-Video media. VOB can contain video, audio, subtitle, menu and navigation contents multiplexed together into a stream form. VOB is based on the MPEG program stream format, but with additional limitations and specifications in the private streams... - Professional Disc
- VCDVCDVCD is a three-letter abbreviation with multiple meanings, as described below:* VCD Athletic, semi-professional football team* Video CD* Voice command device* Value change dump * Vocal cord dysfunction* Visual Communication and Design...
- information on DVD Video format
External links
- DVD at the Open Directory Project
- Dual Layer Explained – Informational Guide to the Dual Layer Recording Process
- DVD Frequently Asked Questions (and Answers)
- DVD Burning and Ripping: A Primer, A Glossary
- YouTube: Segment from 1997 Toshiba DVD demo disc – Technical information about the then-new DVD format, from "DVD Gallery," an in-store demonstration disc from Toshiba.