DVD-R

DVD-R

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DVD-R is a DVD recordable
DVD recordable
DVD recordable and DVD rewritable refer to part of Optical disc recording technologies. DVD optical disc formats that can be recorded by a DVD recorder, , either write once or rewritable format written by laser, as compared to DVD-ROM, which is mass-produced by pressing, primarily for the...

 format. A DVD-R typically has a storage capacity
Computer storage
Computer data storage, often called storage or memory, refers to computer components and recording media that retain digital data. Data storage is one of the core functions and fundamental components of computers....

 of 4.71 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...

. Pioneer has also developed an 8.5 GB dual layer
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...

 version, 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...

, which appeared on the market in 2005.

Data on a DVD-R cannot be changed, whereas a 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...

 (rewritable DVD) can be rewritten multiple (1000+) times. DVD-R(W) is one of three competing industry standard DVD recordable
DVD recordable
DVD recordable and DVD rewritable refer to part of Optical disc recording technologies. DVD optical disc formats that can be recorded by a DVD recorder, , either write once or rewritable format written by laser, as compared to DVD-ROM, which is mass-produced by pressing, primarily for the...

 formats; the others are 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...

(W) 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...

.

History


The DVD-R format was developed by 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...

 in 1997. It is supported by most DVD players, and is approved 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...

.

Technical specifications


The larger storage capacity of a DVD-R compared to a CD-R
CD-R
A CD-R is a variation of the Compact Disc invented by Philips and Sony. CD-R is a Write Once Read Many optical medium, though the whole disk does not have to be entirely written in the same session....

 is achieved through smaller pit size and smaller track pitch of the groove spiral which guides the laser beam. Consequently, more pits can be written on the same physical sized disc. In order to write smaller pits onto the recording dye layer a red laser beam with a wavelength of 640 nm (for general use recordable DVD, versus a wavelength of 780 nm for CD-R) is used in conjunction with a higher numerical aperture
Numerical aperture
In optics, the numerical aperture of an optical system is a dimensionless number that characterizes the range of angles over which the system can accept or emit light. By incorporating index of refraction in its definition, NA has the property that it is constant for a beam as it goes from one...

 lens. Because of this shorter wavelength, DVD-R and DVD+R use different dyes from CD-R to properly absorb this wavelength.

DVD-R discs are composed of two 0.6 mm acrylic
Acrylic glass
Poly is a transparent thermoplastic, often used as a light or shatter-resistant alternative to glass. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate...

 discs, bonded with an adhesive to each other. One contains the laser guiding groove and is coated with the recording dye and a silver alloy or gold reflector. The other one (for single-sided discs) is an ungrooved 'dummy' disc to assure mechanical stability of the sandwich structure, and compatibility with the compact disc standard geometry which requires a total disc thickness of about 1.2 mm. The sandwich structure also helps protect the data containing layer from scratches with a thick 'dummy' disc, a problem with CDs, which lack that structure. Double-sided discs have two grooved, recordable disc sides, and require the user to flip the disc to access the other side. Compared to a CD's 1.2 mm of acrylic, a DVD's laser beam only has to penetrate 0.6 mm of plastic in order to reach the dye recording layer, which allows the lens to focus the beam to a smaller spot size to write smaller pits.

In a DVD-R, the addressing (the determination of location of the laser beam on the disc) is done with additional pits and lands (called land pre-pits) in the areas between the grooves. The groove on a DVD-R disc has a constant wobble frequency
Wobble frequency
DVDs and CDs have their data encoded on a single spiral, or a groove, which covers the surface of the disc. In case the optical medium is recordable, this spiral contains a slight sinusoidal deviation from a perfect spiral. The period of this sine curve corresponds to the wobble frequency...

 used for motor control, etc.

In 2011, 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...

 announced an archival DVD recording media manufactured with quality control and inspection frequencies techniques greater than is traditionally used in media manufacturing, and using specially developed silver alloy as a reflective layer and organic dye with in-house developed additives to secure long-term data retention.

Competing formats


A DVD recordable
DVD recordable
DVD recordable and DVD rewritable refer to part of Optical disc recording technologies. DVD optical disc formats that can be recorded by a DVD recorder, , either write once or rewritable format written by laser, as compared to DVD-ROM, which is mass-produced by pressing, primarily for the...

 format called 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
DVD
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 Discs while having the same dimensions....

 random access memory) predates DVD-R. Developed in 1996, DVD-RAM is a rewritable optical disc usually encased in a cartridge. Currently available in standard 4.7 GB, it is useful in applications that require quick revisions and rewriting. In 2002 a new format was developed called 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...

 (or 'plus' R). Created by a coalition called the DVD+RW Alliance, this format uses a number of improved technologies that, while generally unnoticeable to the end user, make a more reliable technology. One example is the ADIP (ADdress In Pregroove) system of tracking and speed control used by DVD+R being less susceptible to interference and error than the LPP (Land Pre Pit) system used by DVD-R, which makes the ADIP system more accurate at higher speeds. In addition, DVD+R(W) has a more robust error management system than DVD-R(W), allowing for more accurate writing to media independent of the quality of the media. Additional session linking methods are more accurate with DVD+R(W) versus DVD-R(W), resulting in fewer damaged or unusable discs due to buffer under-run and multi-session discs with fewer PI/PO errors.

This new format, among other things, resulted in DVD-R being unofficially referred to as DVD 'minus' R (though in countries where British English is dominant, the term 'minus R' was already common; not just in contrast to 'plus R'). DVD-R and DVD+R technologies are not directly compatible, which created a 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...

 in the DVD technology industry. To reconcile the two competing formats, manufacturers created hybrid drives that could read both – most hybrid drives that handle both formats are labeled DVD±R
DVD±R
DVD±R is not a separate DVD format, but rather is a shorthand term for a DVD drive that can accept both of the common recordable DVD formats . Likewise, DVD±RW handles both common rewritable disc types DVD±R (also DVD+/-R, "DVD plus/dash R", or "DVD plus/minus R") is not a separate DVD format,...

 and Super Multi
Super Multi
Super Multi is a term used to label DVD recorders that support both "minus" and "plus" DVD formats, as well as DVD-RAM....

 (which includes 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...

 support) and are very popular.

As of 2006, the market for recordable DVD technology shows little sign of settling down in favour of either the plus or dash formats, which is mostly the result of the increasing numbers of dual-format devices that can record to both formats; it has become very difficult to find new devices that can only record to one of the formats. However, because the DVD-R format has been in use since 1997, it has had a five-year lead on DVD+R. As such, older or cheaper DVD players (up to 2004 vintage) are more likely to favour the DVD-R standard exclusively.

Recordable DVD capacity comparison


For comparison, the table below shows storage capacities of the four most common DVD recordable media, excluding DVD-RAM. SL stands for standard single-layer discs, while DL denotes the double-layer variants. See articles on the formats in question for information on compatibility issues.

Speed


The following table describes the maximal speed of DVD-R and the relative typical write time for a full disc according to the reviews from cdrinfo.com and cdfreaks.com. Many reviews of multiple brand names on varying conditions of hardware and DVD give much lower and wider measurements than the optimal numbers below.

The write time may vary (± 30 s) between writer and media used. For high speed, the write strategy changes from constant linear velocity
Constant linear velocity
In optical storage, constant linear velocity 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 varies during an operation, as contrasted with CAV modes...

 (CLV) to constant angular velocity
Constant angular velocity
In optical storage, constant angular velocity is a qualifier for the rated speed of an optical disc drive, and may also be applied to the writing speed of recordable discs...

 (CAV)
Drive speed Data rate (MB/s) Data rate (Mbit/s) Write time for single-layer DVD-R
1X 1.32 MB/s 10.56 Mbit/s 60 minute
2X 2.64 MB/s 21.12 Mbit/s 30 minutes (CLV)
4X 5.28 MB/s 42.24 Mbit/s 15 minutes (CLV)
8X 10.56 MB/s 84.48 Mbit/s 8 minutes (Z-CLV)
16X 21.12 MB/s 168.96 Mbit/s 5.75 minutes (CAV)
18X 23.76 MB/s 190.08 Mbit/s 5.5 minutes (CAV)
20X 26.40 MB/s 211.20 Mbit/s 5 minutes (CAV)
22X 29.04 MB/s 232.32 Mbit/s 4.5 minutes (CAV)
24x 31.68 MB/s 253.44 Mbit/s ~4.0 minutes (CAV)

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