DVD From Wikipedia, the free encyclopedia Jump to: navigation, search DVD DVD logo DVD-R read/write side Media type Optical disc Capacity ~4.7 GB (single-sided single-layer), ~8.54 GB (single-sided double-layer) Read mechanism 650 nm laser, 1350 kB/s (1×) Write mechanism 1350 kB/s (1×) Usage Data storage, video, audio, games DVD (also known as "Digital Versatile Disc" or "Digital Video Disc" - see Etymology) is a popular optical disc storage media format. Its main uses are video and data storage. Most DVDs are of the same dimensions as compact discs (CDs) but store more than six times as much data. Variations of the term DVD often describe the way data is stored on the discs: DVD-ROM has data which can only be read and not written, DVD-R and DVD+R can be written once and then function as a DVD-ROM, and DVD-RAM, DVD-RW, or DVD+RW hold data that can be erased and thus re-written multiple times. The wavelength used by standard DVD lasers is 650 nm[1], and thus has a red color. DVD-Video and DVD-Audio discs respectively refer to properly formatted and structured video and audio content. Other types of DVDs, including those with video content, may be referred to as DVD-Data discs. As next generation High definition optical formats also use a disc identical in some aspects yet more advanced than a DVD, such as Blu-ray Disc, the original DVD is often given the retronym SD DVD (for standard definition).[2][3] Contents [hide] * 1 History o 1.1 Etymology * 2 DVD capacity o 2.1 Technology * 3 DVD recordable and rewritable * 4 Dual layer recording * 5 DVD-Video * 6 DVD-Audio o 6.1 Security * 7 Successor * 8 See also * 9 Notes * 10 References * 11 External links [edit] History Optical disc authoring v • d • e * Optical disc * Optical disc image * Optical disc drive * Optical disc authoring * Authoring software * Recording technologies o Recording modes o Packet writing Optical media types * Laserdisc (LD), Video Single Disc (VSD) * Compact Disc (CD): Red Book, 5.1 Music Disc, SACD, PhotoCD, CD-R, CD-ROM, CD-RW, CD Video (CDV), Video CD (VCD), SVCD, CD+G, CD-Text, CD-ROM XA, CD-Extra, CD-i Bridge, CD-i * MiniDisc (MD) (Hi-MD) * DVD: DVD-R, DVD+R, DVD-R DL, DVD+R DL, DVD-RW, DVD+RW, DVD-RW DL, DVD+RW DL, DVD-RAM, DVD-D * Ultra Density Optical (UDO) * Universal Media Disc (UMD) * HD DVD: HD DVD-R, HD DVD-RW, HD DVD-RAM, HD DVD-ROM * Blu-ray Disc (BD): BD-R, BD-RE Standards * Rainbow Books * File systems o ISO 9660 + Joliet + Rock Ridge # Amiga Rock Ridge extensions + El Torito + Apple ISO9660 Extensions o Universal Disk Format (UDF) + Mount Rainier Further reading * History of optical storage media * High definition optical disc format war In 1993, two high-density optical 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. Representatives of the SD camp approached IBM, asking for advice on the file system to use for their disk as well as looking for support for their format for storing computer data. A researcher from IBM's Almaden Research Center received 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 of 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 Disk Format (UDF), for use on the new DVDs. Philips and Sony abandoned their MultiMedia Compact Disc and fully agreed upon Toshiba's SuperDensity Disc with only one modification, namely changing to EFMPlus modulation. EFMPlus was chosen as it has a great resilience against 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.[4] In May 1997, the DVD Consortium was replaced by the DVD Forum, which is open to all other companies. [edit] Etymology "DVD" was originally used as an initialism for the unofficial term "digital videodisk".[5] It was reported in 1995, at the time of the specification finalization, that the letters officially stood for "digital versatile disc" (due to non-video applications),[6] however, the text of the press release announcing the specification finalization only refers to the technology as "DVD", making no mention of what (if anything) the letters stood for.[4] 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.[7] The official DVD specification documents have never defined DVD. Usage in the present day varies, with "DVD", "Digital Video Disc", and "Digital Versatile Disc" being the most common. 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."[8] [edit] DVD capacity Capacity and nomenclature[9][10] Designation Sides Layers Diameter Capacity (cm) (GB) (GiB) DVD-1 [11] 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 4.7 4.37 DVD-9 SS DL 1 2 12 8.54 7.95 DVD-10 DS SL 2 2 12 9.4 8.74 DVD-14[12] DS DL/SL 2 3 12 13.24 12.32 DVD-18 DS DL 2 4 12 17.08 15.90 The basic types of DVD are referred to by a rough approximation of their capacity in gigabytes. The 12 cm type is a standard DVD, and the 8 cm variety is known as a mini-DVD. These are the same sizes as a standard CD and a mini-CD, respectively. Note: Like 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. 230 (or 1,073,741,824) bytes. Most computer operating systems display file sizes in gibibytes, mebibytes and kibibytes labeled as gigabyte, megabyte and kilobyte respectively. Each DVD sector contains 2418 bytes of data, 2048 bytes of which are user data. Size comparison: A 12 cm DVD+RW and a 19 cm pencil. Size comparison: A 12 cm DVD+RW and a 19 cm pencil. There is a small difference in storage space between ‘+’ and ‘-’ formats: Capacity differences of writable DVD formats Type Sectors Bytes GB GiB DVD-R SL 2,298,496 4,707,319,808 4.71 4.384 DVD+R SL 2,295,104 4,700,372,992 4.70 4.378 DVD-R DL 4,171,712 8,543,666,176 8.54 7.957 DVD+R DL 4,173,824 8,547,991,552 8.55 7.961 [edit] Technology Internal mechanism of a DVD-ROM Drive Internal mechanism of a DVD-ROM Drive DVD uses 650 nm wavelength laser diode light as opposed to 780 nm for CD or 405 nm for HD-DVD or Blu-ray Disc. This permits a smaller spot on the media surface (1.32 µm for DVD versus 2.11 µm for CD) compared to CDs. Writing speeds for DVD were 1×, that is 1350 kB/s (1318 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), 9 times slower.[13] DVD drive speeds Drive speed Data rate Write time (min) (Mibit/s) (MB/s) SL DL 1× 10.55 1.35 61 107 2× 21.09 2.70 30 54 2.6× 27.43 3.51 24 42 4× 42.19 5.40 15 27 6× 63.30 8.10 11 18 8× 84.38 10.80 8 14 16× 168.75 21.60 4 7 [edit] DVD recordable and rewritable Main article: DVD recordable HP initially developed recordable DVD media from the need to store data for back-up and transport. DVD recordables are now also used for consumer audio and video recording. Three formats were developed: DVD-R/RW (minus/dash), DVD+R/RW (plus), DVD-RAM. [edit] Dual layer recording Dual Layer recording allows DVD-R and DVD+R discs to store significantly more data, up to 8.5 gigabytes per side, per disc, compared with 4.7 gigabytes for single-layer discs. 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).[14] 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 semi-transparent layer. The layer change can exhibit a noticeable pause in some DVD players, up to several seconds.[15] This caused more than a few 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.[14] Many current DVD recorders support dual-layer technology, and the price is now comparable to that of single-layer drives, though the blank media remains more expensive. The recording speeds reached by dual-layer media are still well below those of single-layer media. 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 DVD-Video, 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.[16] [edit] DVD-Video Main article: DVD-Video DVD-Video is a standard for storing video content on DVD media. In the U.S., mass retailer sales of DVD-Video titles and players began in late 1997.[17] By June 2003, weekly DVD-Video rentals began out-numbering weekly VHS cassette rentals, reflecting the rapid adoption rate of the technology in the U.S. marketplace.[18] Currently DVD-Video is the dominant form of home video in the United States, Europe and Australia. After A History of Violence was released on VHS and DVD in 2006, all Hollywood movies have been released on DVD exclusively. Though many resolutions and formats are supported, most consumer DVD-Video discs use either 4:3 or anamorphic 16:9 aspect ratio MPEG-2 video, stored at a resolution of 720×480 (NTSC) or 720×576 (PAL) at 29.97 or 25 FPS. Audio is commonly stored using the Dolby Digital (AC-3) or Digital Theater System (DTS) formats, ranging from 16-bits/48 kHz to 24-bits/96 kHz format with monaural to 7.1 channel "Surround Sound" presentation, and/or MPEG-1 Layer 2. Although the specifications for video and audio requirements vary by global region and television system, many DVD players support all possible formats. DVD-Video also supports features like menus, selectable subtitles, multiple camera angles, and multiple audio tracks. [edit] DVD-Audio Main article: DVD-Audio DVD-Audio is a format for delivering high-fidelity audio content on a DVD. It offers many channel configuration options (from mono to 5.1 surround sound) at various sampling frequencies (up to 24-bits/192 kHz versus CDDAs 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 rates and greater bit-depth, 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. [edit] Security Main article: Content Protection for Recordable Media DVD-Audio discs employ a robust[citation needed] copy prevention mechanism, called Content Protection for Prerecorded Media (CPPM) developed by the 4C group (IBM, Intel, Matsushita, and Toshiba). To date, CPPM has not been "broken" in the sense that DVD-Video's CSS has been broken, but ways to circumvent it have been developed.[19] By modifying commercial DVD(-Audio) playback software to write the decrypted and decoded audio streams to the hard disk, users can, essentially, extract content from DVD-Audio discs much in the same way they can from DVD-Video discs. [edit] Successor There were two potential successors to DVD being developed by different consortia. One was the DVD Forum's HD DVD, designed by Toshiba, and the other was the Blu-ray Disc (BD), designed by Sony and Panasonic. The two formats were engaged in a format war from 2006 to 2007. In January 2008, Warner Bros. dropped support for HD DVD, while the next month, Wal-Mart announced that it would follow suit.[20] On February 19, 2008, Toshiba announced that they would discontinue the development of HD DVD. However, unlike previous format changes (i.e. vinyl records to compact disc, 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 97% of video sales.[21] Consumers have been slow to adopt either Blu-ray or HD DVD, partially due to the consumer confusion and indifference from the format war. The initial cost has also been a major deterrent, with high definition players selling for $500 USD or more, while titles retail for $30 USD or higher, plus one requires a high-definition TV and appropriate connection cords to take advantage of it. 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.[22] The DVD had succeeded because it offered a compelling alternative to VHS. [edit] See also * DVD authoring * DVD formats * DVD region code * DVD TV games * DVD-Video * MiniDVD [edit] Notes 1. ^ Build Your Skills: A comparison between DVD and CD-ROM. 2. ^ DVD-Workshop: University of Utah and elsewhere, e.g. as the SD export preset for standard definition DVDs in Final Cut Pro. 3. ^ [1]. 4. ^ a b Toshiba (December 8, 1995). "DVD Format Unification". Press release. Retrieved on 2007-07-12. 5. ^ A Battle for Influence Over Insatiable Disks. New York Times (1995-01-11). Retrieved on 2007-04-09. 6. ^ DVD designers go with AC-3 Final specs for 'digital versatile disc'.... The Hollywood Reporter (1995-12-11). Retrieved on 2007-04-16. 7. ^ DVD FAQ. DVD Demystified (2006-09-12). 8. ^ DVD Primer. DVD Forum (November 14, 2004). Retrieved on 2008-01-23. 9. ^ Physical parameters 10. ^ DVD in Detail 11. ^ Dvd Faq 12. ^ DVD-14. AfterDawn Ltd.. Retrieved on 2007-02-06. 13. ^ DVD FAQ 14. ^ a b Robert DeMoulin. Understanding Dual Layer DVD Recording. BurnWorld.com. Retrieved on 2007-07-06. 15. ^ DVD players benchmark. hometheaterhifi.com. Retrieved on 2008-04-01. 16. ^ Disc USA 17. ^ Discount stores are a video lover's channel of choice. Discount Store News (via findarticles.com) (1998-08-10). Retrieved on 2008-03-06. 18. ^ Bakalis, Anna (2003-06-20). It's unreel: DVD rentals overtake videocassettes. Washington Times. 19. ^ DVD-Audio's CPPM can be got around with a WinDVD patch. Retrieved on 2007-07-06. 20. ^ Wal-Mart picks Blu-Ray over HD DVD, Charlottetown Guardian, Feb. 15, 2008, accessed Feb. 19, 2008 21. ^ [2] 22. ^ [3] [edit] References * Bennett, Hugh (April 2004). Understanding Recordable & Rewritable DVD. Optical Storage Technology Association. Retrieved on 2006-12-17. * Labarge, Ralph. DVD Authoring and Production. Gilroy, Calif.: CMP Books, 2001. ISBN 1-57820-082-2. * Taylor, Jim. DVD Demystified, 2nd edition. New York: McGraw-Hill Professional, 2000. ISBN 0-07-135026-8. [edit] External links Wikibooks Wikibooks has a book on the topic of All About Converting From Several Video Formats To DVD * DVD Forum * DVD+RW Alliance * DVD Copy Control Association and the Content Scramble System (CSS) * Dual Layer Explained – Informational Guide to the Dual Layer Recording Process * Understanding Recordable & Rewritable DVD by Hugh Bennett * DVD Frequently Asked Questions (and Answers) * DVDs: in the fast lane * History of DVD technology from the Consumer Electronics Association * How Stuff Works - DVD [show] v • d • e Video storage formats Videotape Analog Quadruplex (1956) · VERA (1958) · Type A (1965) · CV-2000 (1965) · Akai (1967) · U-matic (1969) · EIAJ-1 (1969) · Cartrivision (1972) · Philips VCR (1972) · V-Cord (1974) · VX (1974) · Betamax (1975) · IVC (1975) · Type B (1976) · Type C (1976) · VHS (1976) · VK (1977) · SVR (1979) · Video 2000 (1980) · CVC (1980) · VHS-C (1982) · M (1982) · Betacam (1982) · Video8 (1985) · MII (1986) · S-VHS (1987) · Hi8 (1989) · S-VHS-C (1987) · W-VHS (1994) Digital D1 (1986) · D2 (1988) · D3 (1991) · DCT (1992) · D5 (1994) · Digital Betacam (1993) · DV (1995) · Digital-S (D9) (1995) · DVCPRO (1995) · Betacam SX (1996) · DVCAM (1996) · HDCAM (1997) · DVCPRO50 (1998) · D-VHS (1998) · Digital8 (1999) · DVCPRO HD (2000) · D6 HDTV VTR (2000) · MicroMV (2001) · HDV (2003) · HDCAM SR (2003) Videodisc Analog Phonovision (1927) · TeD (1975) · Laserdisc (1978) · Laserfilm (1984) · CD Video (1983?) Digital VCD (1985) · MovieCD (1995?) · DVD/DVD-Video (1995) · MiniDVD · CVD (1998) · SVCD (1998) · EVD (2003) · XDCAM (2003) · HVD (2004) · FVD (2005) · UMD (2005) · VMD (2006) · HD DVD (2006) · Blu-ray Disc (2006) Other Solid state P2 (2004) · SxS (2007) Non-video TV recording Kinescope (1947) · Electronicam kinescope (1950s) · Electronic Video Recording (1967) Retrieved from "http://en.wikipedia.org/wiki/DVD" Categories: Optical disc authoring | Computer storage media | Audio storage | Video storage | DVD | 120 mm discs | Consumer electronics | 1995 introductions | Joint ventures Hidden categories: All articles with unsourced statements | Articles with unsourced statements since April 2008 Views * Article * Discussion * Edit this page * History Personal tools * Log in / create account Navigation * Main Page * Contents * Featured content * Current events * Random article Interaction * About Wikipedia * Community portal * Recent changes * Contact Wikipedia * Donate to Wikipedia * Help Search Toolbox * What links here * Related changes * Upload file * Special pages * Printable version * Permanent link * Cite this page Languages * Afrikaans * Alemannisch * العربية * Asturianu * AzÉ™rbaycan * বাংলা * Bosanski * Български * Català * ÄŒesky * Cymraeg * Dansk * Deutsch * Eesti * Ελληνικά * Español * Esperanto * Euskara * فارسی * Français * Frysk * Galego * 한국어 * Hrvatski * Ido * Bahasa Indonesia * Íslenska * Italiano * עברית * ქართული * Lietuvių * Magyar * Bahasa Melayu * Nahuatl * Nederlands * 日本語 * ‪Norsk (bokmål)‬ * ‪Norsk (nynorsk)‬ * Polski * Português * Română * Русский * Shqip * Simple English * Slovenčina * SlovenšÄina * Српски / Srpski * Srpskohrvatski / Српскохрватски * Suomi * Svenska * Tagalog * ไทย * Tiếng Việt * Тоҷикӣ/tojikÄ« * Türkçe * Українська * 粵語 * 中文 Powered by MediaWiki Wikimedia Foundation * This page was last modified on 2 May 2008, at 23:45. * All text is available under the terms of the GNU Free Documentation License. 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