Recordable DVD Media Formats The Current State of Recordable DVD Media Formats CD-R 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 hardware and media dropping, the DVD recordable formats are rapidly gaining acceptance for use in document, video, audio and personal/professional storage. The prime selling points 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 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. While the DVD formats have important technical There are basically two markets for recordable differences, the charts below have been developed DVD: computer storage and A/V recording. While to help content developers and users determine all of the format developers have focused on which media is best for them. providing a single format that will work for both video and computer applications, each DVD General Format Discussion format has its strengths and weaknesses DVD-R, a recordable version of DVD-ROM - The DVD Forum has developed specifications for two Each DVD format has its write-once DVD-R categories - Authoring and strengths and weaknesses General use. Although both types of DVD-R media can be read by nearly all DVD drives and players, technical differences make it impossible to write to Applications DVD-R Authoring media using a consumer DVD-R General system and vice versa. DVD-R General All DVD media formats share common parameters recorders use a 650 nm recording laser for use in a wide range of personal and wavelength while DVD-R Authoring use a 635 nm professional applications. The discs look very laser. In addition, the General Use media contains similar; however, they do not all work in every DVD content protection technology to prevent users drive, DVD-Video player or DVD recorder. from making bit-for-bit copies of CSS- encrypted entertainment titles. Verbatim / April-2002 Recordable DVD Media Formats 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 erasure. Low-cost DVD+R media will be used with storage cost, 100-year data life and broad DVD+R/+RW drives and video recorders compatibility also make DVD-R General media announced by HP, Dell, Philips, Ricoh and Sony. ideal for small-scale distribution of DVD content. DVD-R general discs can be played back by the vast majority of the DVD-ROM drives and video players in use today. Available with street prices as low as £5.00, 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 specification is an extension of the DVD+RW format supported by the DVD+RW alliance: 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 Verbatim / April-2002 Recordable DVD Media Formats DVD-RW - DVD-RW is officially referred to as DVD-RAM-DVD-RAM (DVD Random Access a "re-recordable" format by the DVD Forum, but is Memory), the rewriteable format developed by the commonly known as a rewriteable format. DVD Forum, provides 100,000 write/rewrite cycles. Available with a capacity of 4.7GB, DVD-RW media DVD-RAM features random write/read support, so is recorded sequentially, making it ideal for data, video and audio can be stored and accessed streaming video applications. DVD-RW media like a hard drive using standard drag-and-drop contains protection technology that prevents techniques. DVD-RAM also offers Defect Sector copying of copyrighted content. Users can write to Management (DSM) to ensure that randomly the disc in multiple sessions as long as the disc has written data is only placed in usable areas of the not been finalized, but DVD drives and players can media and that data is accurately recovered during only read DVD-RW media after the disc has been the read, write processes. No finalization is finalized. Currently offering 1x write performance, required, so users do not have to open and close DVD-RW discs can be overwritten 1,000 times. write sessions. However, the format specifications Most legacy DVD-ROM drives and DVD players, that allow these hard-drive like features also especially those produced in the past two years, renders DVD-RAM media incompatible with most will read DVD-RW media. Available at street DVD-ROM drives and set-top video players. pricing approaching £10.00, DVD-RW discs are Single-sided (4.7GB) and double-sided (9.4GB) used by drives and video recorders from Pioneer, media are available as bare discs or enclosed in a Compaq, Sony and other manufacturers. cartridge, with end-user pricing ranging from £10 to £35. DVD-RAM discs are used with drives and DVD+RW - Introduced in October 2001, video recorders from Panasonic, Hitachi, Toshiba, DVD+RW is a rewriteable format developed by the LaCie, QPS and others. DVD+RW Alliance. Offering 2.4x recording and 1,000 rewrites, the 4.7GB DVD+RW technology is CLV vs. CAV Recording Methods used by consumers for both audio/video and data When selecting a DVD format, the intended storage applications. DVD+RW incorporates application (computer or AV) and the technology lossless linking technology, allowing the drive or used to carry out the recording process should be video recorder to accurately stop and start the considered. Basically, there are two recording writing process, or to replace individual 32kB data methods: Constant Angular Velocity (CAV) which is blocks. Lossless linking improves compatibility, used in high-speed access applications such as performance and ease of use, and permits support computer storage and Constant Linear Velocity of drag-and-drop applications like the Mount (CLV) which is used in streaming video Ranier specification (similar to CD-RW applications. functionality). For PC applications, DVD+RW hardware can optionally support CAV (constant angular velocity) recording to enable fast, random- When selecting a DVD format, access reading of the disc. With multi-session the intended application writing technology, users who have not finalized (computer or AV) and the the disc can quickly add documents, data and technology used to carry out the video segments without having to open and close recording process should be write sessions. By incorporating the +RW considered. specification for defect management, manufacturers ensure that data is accurately written to and read from the disc. DVD+RW media, Most magnetic disk drives use CAV storage, where which is currently available for £10.00 to £15.00, is the drive rotates at a constant rpm (revolutions per compatible with +RW drives and video recorders minute), no matter what section of the disc is being from HP, Philips, Sony, Dell Computer and other read. With the ability to provide quick random leading manufacturers. access, CAV is favored for computer and game read/write storage. Verbatim / April-2002 RecordableRecordable DVD DVD Media Media Formats Formats The DVD-R and DVD-RW formats use CLV technology, the mode used for the various CD When selecting a media brand, formats and DVD-Video. With CLV, the drive rotates users should consider the at different rpms, depending on what track of the manufacturer's reputation for disc the laser is reading, to maintain a constant quality. data transfer rate. The CLV mode enables higher data transfer rates than CAV, which makes it the preferred recording mode for streaming video, but Other problems occur because the player or drive's it slows access when searching for data. capabilities and firmware are marginally designed to meet minimum specifications. As DVD format DVD-RAM, DVD+RW and DVD+R offer a specifications have been finalized, many drive and combination of recording solutions that make player manufacturers have enhanced their read them suitable for both computer and video mechanisms to improve compatibility with the storage. various media. By making sure that the media has been qualified by the drive manufacturer, users can DVD-RAM discs use Zoned CLV (ZCLV), a avoid having to deal with these types of issues. combination of CLV and CAV that allows data to be transferred at a variable rate while the drive spins at Because DVD format specifications have been a constant rate, like a hard disk. finalized at various times since 1997, it is difficult for drive, player or recorder manufacturers to The DVD+RW and DVD+R formats utilize completely eliminate compatibility issues for sequential CLV recording to provide high data Recordable DVD media with all legacy DVD-ROM transfer rates and offer CAV as an option when drives and DVD players.