The current state of recordable DVD media formats.CD-R (CD-Recordable) A writable CD technology using a type of compact disc that can be recorded, but not erased (CD-Rs are "write once" discs). CD-R discs are used to master CD-ROMs, to back up data and to make copies of data for distribution. and -RW continue to be the most widely used removable storage technology because of the extremely low cost of drives, players, and media. However, with prices for DVD DVD: see digital versatile disc. DVD in full digital video disc or digital versatile disc Type of optical disc. The DVD represents the second generation of compact-disc (CD) technology. hardware and media dropping, the DVD recordable DVD recordable and DVD rewritable refer to DVD optical disc formats that can be recorded (written, "burned"), either or rewritable (write multiple times) format written by laser, as compared to DVD-ROM, which is mass-produced by pressing. formats are rapidly gaining acceptance for use in document, video, audio, and personal/professional storage. The prime selling points selling point n. An aspect of a product or service that is stressed in advertising or marketing. Noun 1. selling point - a characteristic of something that is up for sale that makes it attractive to potential customers of DVD are its inherent reliability and massive data storage capabilities--ultimately up to 9.4GB of removable storage with a double-sided disc. According to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. Wolfgang Schlichting, IDC's Research Manager, Removable Storage, 2002 will be the year when many consumers will discover the benefits of DVD recording. IDC projects that worldwide DVD media sales will climb from 50 million discs in 2002 to nearly 150 million in 2004. There are basically two markets for recordable DVD See DVD-R, DVD-RW, DVD+RW and DVD-RAM. : computer storage and A/V (1) (Audio/Video) Refers to equipment and applications that deal with sound and sight. The A/V world includes microphones, tape recorders, audio mixers, still and video cameras, film projectors, slide projectors, VCRs, CD and DVD players/recorders, amplifiers and recording. While all of the format developers have focused on providing a single format that will work for both video and computer applications, each DVD format See VOB and DVD. has its strengths and weaknesses Applications All DVD media formats share common parameters for use in a wide range of personal and professional applications. The discs look very similar; however, they do not all work in every DVD drive, DVD-Video player, or DVD recorder (1) A recordable or rewritable DVD drive that is connected to the computer. It may be an internal or external device. See DVD drives, DVD-R, DVD-RW, DVD+R and DVD+RW. (2) . While the DVD formats There are several competing DVD Formats: Non-recordable formats
General Format Discussion DVD-R (DVD-Recordable) A write-once (read only) DVD disc for both movies and data endorsed by the DVD Forum. DVD-Rs are often called "DVD Dash Rs" or "DVD Minus Rs" to distinguish them from the competing "Plus R" format (see DVD+R). , a recordable version of DVD-ROM--The DVD Forum A membership organization devoted to defining DVD standards for read-only, rewritable, write-once, video and audio use. Members participate in working groups to develop new standards. has developed specifications for two write-once DVD-R categories--Authoring and General use. Although both types of DVD-R media can be read by nearly all DVD drives DVD drives come in a variety of speeds and options. The original drive (1x) transferred data at 1.35MB per second. By doubling the spindle speed (RPMs) for 2x drives, the transfer rate increased to 2.7MB/sec and has been increasing ever since. and players, technical differences make it impossible to write to DVD-R Authoring media using a consumer DVD-R General system and vice versa VICE VERSA. On the contrary; on opposite sides. . DVD-R General recorders use a 650 nm recording laser wavelength while DVD-R Authoring uses a 635 nm laser. In addition, the General Use media contains content protection technology to prevent users from making bit-for-bit copies of CSS- encrypted entertainment titles (Table 3). DVD-R for Authoring was designed to meet the needs of professional content developers and software producers. The media is primarily used to create master discs that will be mass produced by software houses, multimedia/video post-production facilities, and archiving. DVD-R for General Use was developed for business and consumer applications--data archiving and one-time video recording. Delivering 2X write performance, which is equivalent to an 18x CD write speed, the media provides secure recording for volumes of information that cannot be accidentally or intentionally altered. The low storage cost, 100-year data life, and broad compatibility also make DVD-R General media ideal for small-scale distribution of DVD content. DVD-R general discs can be played back by the vast majority of the DVD-ROM DVD-ROM: see digital versatile disc. A read-only DVD disc used to permanently store data files. DVD-ROM discs are widely used to distribute large software applications that exceed the capacity of a CD-ROM disc. drives and video players in use today. Available with street prices as low as $5, the media can be used by DVD-R General drives from Pioneer, Apple, Compaq, Sony, Panasonic, and other leading manufacturers. DVD+R--The write-once DVD+R (DVD+Recordable) A write-once (read only) version of the DVD+RW optical disc from the DVD+RW Alliance. DVD+Rs hold up to 4.7GB of data per side and can be read by DVD-Video players and computer DVD-ROM drives. A DVD+R DL disc is a "dual layer" DVD+R that holds a total of 8.5GB. specification is an extension of the DVD+RW (DVD+Read Write) A rewritable (re-recordable) DVD disc for both movies and data from the DVD+RW Alliance. DVD+RW media can be read on DVD-Video players and computer DVD-ROM drives. format supported by the DVD+RW alliance An industry consortium devoted to promoting rewritable and write-once DVD standards. Founded in 1997 by HP, Philips, Sony and others, it developed the DVD+RW specification as an evolution of the CD-RW format. : HP, Philips, Ricoh, Sony, Yamaha, Verbatim/ Mitsubishi Chemical, Dell, and Thomson. Similar in functionality and compatibility to DVD-R General, DVD+R was designed to provide widespread playback on DVD-ROM drives and DVD video players. DVD+R/+RW drives write at 2.4x speed, recording a full DVD disc about 5 minutes faster than 2x writers. DVD+R drives and media provide a reliable, low-cost storage solution for archiving home videos, photos, mixed media presentations, and data that require protection from alteration or erasure ERASURE, contracts, evidence. The obliteration of a writing; it will render it void or not under the same circumstances as an interlineation. (q.v.) Vide 5 Pet. S. C. R. 560; 11 Co. 88; 4 Cruise, Dig. 368; 13 Vin. Ab. 41; Fitzg. 207; 5 Bing. R. 183; 3 C. & P. 65; 2 Wend. R. 555; 11 Conn. . Low-cost DVD+R media will be used withDVD+R/+RW drives and video recorders announced by HP, Dell, Philips, Ricoh, and Sony. DVD-RW--DVD-RW is officially referred to as a "re-recordable" format by the DVD Forum, but is commonly known as a rewriteable format. Available with a capacity of 4.7GB, DVD-RW (DVD-Read Write) A rewritable (re-recordable) DVD disc for both movies and data from the DVD Forum. Also called "DVD Dash RW" and "DVD Minus RW," DVD-RW uses phase change recording. The media hold 4.7GB per side and can be rewritten 1,000 times. media is recorded sequentially, making it ideal for streaming video A one-way video transmission over a data network. It is widely used on the Web as well as company networks to play video clips and video broadcasts. Computers in home networks stream video to digital media hubs connected to a home theater. applications. DVD-RW media contains protection technology that prevents copying of copy-righted content. Users can write to the disc in multiple sessions as long as the disc has not been finalized, but DVD drives and players can only read DVD-RW media after the disc has been finalized. Currently offering 1x write performance, DVD-RW discs can be overwritten 1,000 times. Most legacy DVD-ROM drives and DVD players, especially those produced in the past two years, will read DVD-RW media. Available at street pricing approaching $10, DVD-RW discs are used by drives and video recorders from Pioneer, Compaq, Sony, and other manufacturers. DVD+RW--Introduced in October 2001, DVD+RW is a rewriteable format developed by the DVD+RW Alliance.Offering 2.4x recording and 1,000 rewrites, the 4.7GB DVD+RW technology is used by consumers for both audio/video and data storage applications. DVD+RW incorporates lossless See lossless compression. (algorithm, compression) lossless - A term describing a data compression algorithm which retains all the information in the data, allowing it to be recovered perfectly by decompression. Unix compress and GNU gzip perform lossless compression. linking technology, allowing the drive or video recorder to accurately stop and start the writing process, or to replace individual 32kB data blocks. Lossless linking improves compatibility, performance, and ease of use, and permits support of drag-and-drop applications like the Mount Ranier See Mount Rainier. specification (similar to CD-RW (CD-ReWritable) The only rewritable CD technology. CD-RW disks look like other CD media, but with close inspection, they have a more polished surface with a very dark blue-gray cast. functionality). For PC applications, DVD+RW hardware can optionally support CAV (1) (Component Analog Video) See YPbPr. (2) (Constant Angular Velocity) Rotating an optical disc or hard disk at a constant speed. Contrast with "constant linear velocity" (CLV), in which the platter rotates at varying speeds. (constant angular velocity (storage) constant angular velocity - (CAV) A disk driving scheme in which the angular velocity of the disk is kept constant. This means that the linear velocity of the disk be larger when the reading or writing the outer tracks. ) recording to enable fast, random-access reading of the disc. With multi-session writing technology, users who have not finalized the disc can quickly add documents, data, and video segments without having to open and close write sessions. By incorporating the +RW specification for defect management (1) The elimination of bugs in software and flaws in hardware. Defect management is part of a software or hardware development project. (2) The prevention of data errors in a storage medium by invalidating bad sectors. , manufacturers ensure that data is accurately written to and read from the disc. DVD+RW media, which is currently available for $10 to $15, is compatible with +RW drives and video recorders from HP, Philips, Sony, Dell Computer, and other leading manufacturers. DVD-RAM--DVD-RAM (DVD Random Access Memory), the rewriteable format developed by the DVD Forum, provides 100,000 write/rewrite cycles. DVD-RAM A rewritable DVD disc endorsed by the DVD Forum. Using phase change technology, DVD-RAMs are like removable hard disks, and the media can be rewritten 100,000 times compared to 1,000 times for DVD-RW and DVD+RW. The first DVD-RAM drives with a capacity of 2.6GB (single sided) or 5. features random write/read support, so data, video, and audio can be stored and accessed like a hard drive using standard drag-and-drop techniques. DVD-RAM also offers Defect Sector Management (DSM 1. DSM - Data Structure Manager. An object-oriented language by J.E. Rumbaugh and M.E. Loomis of GE, similar to C++. It is used in implementation of CAD/CAE software. DSM is written in DSM and C and produces C as output. ) to ensure that randomly written data is only placed in usable areas of the media and that data is accurately recovered during the read, write processes. No Finalization is required, so users do not have to open and close write sessions. However, the format specifications that allow these hard-drive like features also renders DVD RAM media incompatible with most DVD-ROM drives and set-top video players. Single-sided (4.7GB) and double-sided (9.4GB) media are available as bare discs or enclosed in a cartridge, with end user pricing ranging from $10 to $35. DVD-RAM discs are used with drives and video recorders from Panasonic, Hitachi, Toshiba, LaCie, QPS (Queries Per Second) The number of database transactions that can be handled in one second. , and others. CLV (Constant Linear Velocity) Rotating a disk at varying speeds. By changing speed depending on which track is being accessed, the density of bits in each track can be made uniform. vs. CAV Recording Methods When selecting a DVD format, the intended application (computer or AV) and the technology used to carry out the recording process should be considered. Basically, there are two recording methods: Constant Angular Velocity (CAV), which is used in high-speed access applications such as computer storage, and Constant Linear Velocity (storage) constant linear velocity - (CLV) A disk driving scheme in which the linear velocity of the disk is kept constant. This requires that the angular velocity of the disk be larger when the reading or writing tracks closer to the axis. (CLV), which is used in streaming video applications. Most magnetic disk drives use CAV storage, where the drive rotates at a constant rpm (revolutions per minute), no matter what section of the disc is being read. With the ability to provide quick random access, CAV is favored for computer and game read/write storage. The DVD-R and DVD-RW formats use CLV technology, the mode used for the various CD formats and DVD-Video. With CLV, the drive rotates at different rpms, depending on what track of the disc the laser is reading, to maintain a constant data transfer rate. The CLV mode enables higher data transfer rates than CAV, which makes it the preferred recording mode for streaming video, but it slows access when searching for data. DVD-RAM, DVD+RW, and DVD+R offer a combination of recording solutions that make them suitable for both computer and video storage. DVD-RAM discs use Zoned CLV See CLV. (ZCLV See CLV. ), a combination of CLV and CAV that allows data to be transferred at a variable rate while the drive spins at a constant rate, like a hard disk. The DVD+RW and DVD+R formats utilize sequential CLV recording to provide high data transfer rates and offer CAV as an option when random access is required. Solving Playback Issues Pressed media (DVD-Video, DVD-ROM) is most easily read by all DVD drives and players. Write-once media, DVD-R and DVD+R, is the next most easily read. The rewriteable formats--DVD-RW, DVD+RW, and DVD-RAM--are more difficult to read, but -RW and +RW still have good compatibility because their formats closely resemble that of pressed media. Compatibility problems arise when media does not meet the physical specifications for data format, recording properties, and reflectivity re·flec·tiv·i·ty n. pl. re·flec·tiv·i·ties 1. The quality of being reflective. 2. The ability to reflect. 3. , typically due to poor media manufacturing procedures. When selecting a media brand, users should consider the manufacturer's reputation for quality. Archives of mission-critical information and precious memories deserve the highest quality media. Other problems occur because the player or drive's capabilities and firmware A category of memory chips that hold their content without electrical power. Firmware includes flash, ROM, PROM, EPROM and EEPROM technologies. When holding program instructions, firmware can be thought of as "hard software." See flash memory, ROM, PROM, EPROM, EEPROM and FOTA. are marginally designed to meet minimum specifications. As DVD format specifications have been finalized, many drive and player manufacturers have enhanced their read mechanisms to improve compatibility with the various media. By making sure that the media has been qualified by the drive manufacturer, users can avoid having to deal with these types of issues. Because DVD format specifications have been finalized at various times since 1997, it is difficult for drive, player, or recorder manufacturers to completely eliminate compatibility issues for Recordable DVD media with all legacy DVD-ROM drives and DVD players. Similar problems existed in the early days of CD-R/RW technology development. Compatibility is improving; and eventually, peripheral manufacturers and users won't have to worry about the compatibility of the recordable DVD format they use to store data, videos, and music. Recognizing that no single format currently offers everything users want, drive manufacturers have introduced combination drives that support both write-once and rewriteable DVD media--DVD-R/-RAM drives, DVD-RW drives, and DVD+R/ +RW drives. By combining a write-once DVD format with a rewriteable DVD format, the drives provide a single solution for sharing and archiving on broadly compatible DVD-R or DVD+R media and the ability to use rewriteable media for files that can be edited and recycled.
Table 1
What Works Where?
DVD Format Typical Supporting
Manufacturers Organization
DVD-R Authoring Pioneer DVD Forum
DVD-R/RW * Pioneer DVD Forum
LaCie
QPS
CD Cyclone
DVD-RW/+R * Ricoh DVD+RW
H-P Alliance (8C)
Philips
Sony
Thompson
DVD-RAM/R Panasonic DVD Forum
Hitachi
LG Electronics
Samsung
LaCie
QPS
DVD SuperMulti * Hitachi DVD Forum
Panasonic
LG Electronics
LaCie
QPS
DVD Multi * LG Electronics DVD Forum
DVD+RW
Alliance
DVD Format Primary Compatible
Application Media
DVD-R Authoring Content DVD-R(A)
Development
DVD-R/RW * Video DVD-R(G)
Development, DVD-RW
archiving
DVD-RW/+R * Computer, DVD-RW
Video DVD+R
DVD-RAM/R Computer, DVD-RAM
Video, DVD-R(G)
Optical Libraries
DVD SuperMulti * Computer, DVD-RAM
Video, DVD-R(G)
Libraries DVD-RW
DVD Multi * Computer, DVD-RAM
Video DVD-R(G)
DVD-RW
DVD+R
* Drives also write all published CD format media
Table 2
DVD Format Feature Comparison
Format Write Read Random Defect Rewrites
Speed Capability Write Mgmt.
DVD-R 2X Excellent No No -0-
DVD+R 2.4X Excellent No No -0-
DVD-RW 1X Good No No 1,000
DVD+RW 2.4X Good Yes Yes 1,000
(as option) (by drive)
DVD-RAM 2X Poor Yes Yes 100,000
(on disc)
Table 3
DVD Media Specifications
DVD-R DVD-R DVD+R
Authoring General 4.7/
9.4GB
Capacity 4.7GB 4.7GR/side 4.7GB
Laser Wavelength 635nm 650nm 650nm
Numerical 0.6 0.6
Aperture
Recording Layer Dye Dye
Reflectivity 45-85% 45-85%
Modulation 0.6 min. 0.6 min.
Amplitude
Data Track Form Wobbled groove + Phase modulated
Land pre-pit wobbled groove
Track Pitch 0.74[micro]m 0.74[micro]m
Tracking Method DPD DPD
(reading)
Min. Pit Length 0.40[micro]m 0.40[micro]m
Data Modulation 8/16, RLL(2,10) 8/16, RLL(2,10)
Error Correction RS-PC RS-PC
Channel Bit Rate 26.16Mbps 26.16Mbps
Scanning Velocity 3.49 m/s 3.49-8.44 m/s
Rewritability N/A N/A
Copy Protection None CSS CSS
DVD-RW DVD+RW DVD-RAM
4.7/9.4GB 4.7/9.4GB
Capacity 4.7GB 4.7GB/side 4.7GB/side
Laser Wavelength 650nm 650nm 650nm
Numerical 0.6 0.65 0.6
Aperture
Recording Layer Phase-Change Phase-Change Phase-Change
Reflectivity 18-30% 18-30% 15-25%
Modulation 0.6 min. 0.6 min. 0.4 min.
Amplitude
Data Track Form Wobbled groove + Phase modulated Wobbled land &
Land pre-pit wobbled groove groove +
Pre-pit
Track Pitch 0.74[micro]m 0.74[micro]m 0.615[micro]m
Tracking Method DPD DPD DPD
(reading)
Min. Pit Length 0.40[micro]m 0.40[micro]m 0.420[micro]m
Data Modulation 8/16, RLL(2,10) 8/16, RLL(2,10) 8/16,
RLL(2,10)
Error Correction RS-PC RS-PC RS-PC
Channel Bit Rate 26.16Mbps 26.16Mbps 58.36Mbps
Scanning Velocity 3.49 m/s 3.49-8.44m/s 8.16-8.49m/s
Rewritability 1,000 1,000 100,000
Copy Protection CSS, CPRM CSS CSS, CPRM
www.verbatim.com Tim Clatterbuck is the product manager of Optical Media at Verbatim Corp. (Charlotte, NC). |
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