Chapter 1

126 Everything You Ever Wanted to Know About DVD
verify. Third, DVD-R does not directly support CSS, regions, and Macrovision.
Support for this is being added to DVD-R(A) with the cutting master
format (CMF), which stores DDP information in the control area, but it will
take a while before many authoring software programs and replicators
support CMF.
DVD-RW
DVD-RW (formerly DVD-R/W and also briefly known as DVD-ER) is a
phase-change erasable format. Developed by Pioneer based on DVD-R,
using similar track pitch, mark length, and rotation control, DVD-RW is
playable in many DVD drives and players. (Some drives and players are
confused by DVD-RW media’s lower reflectivity into thinking it’s a dual-layer
disc. In other cases the drive or player doesn’t recognize the disc format
code and doesn’t even try to read the disc. Simple firmware upgrades can
solve both problems.) DVD-RW uses groove recording with address info on
land areas for synchronization at write time (land data is ignored during
reading). Capacity is 4.7 billion bytes. DVD-RW discs can be rewritten about
1,000 times.
In December 1999, Pioneer released DVD-RW home video recorders in
Japan. The units cost 250,000 yen (about $2,500) and blank discs cost
3,000 yen (about $30). Since the recorder used the new DVD-VR (video
recording) format, the discs wouldn’t play in existing players (the discs were
physically compatible, but not logically compatible). Recording time varies
from 1 hour to 6 hours, depending on quality. A new version of the recorder
was later released that also recorded on DVD-R(G) discs and used the
DVD-Video format for better compatibility with existing players.
DVD-RW drives write DVD-R, DVD-RW, CD-R, and CD-RW discs. DVD-
RW disc prices are around $5 to $10 (down from the original $30). Blank
media are made by CMC Magnetics, Hitachi Maxell, Mitsubishi, Mitsui,
Pioneer, Ricoh, Ritek, Sony, Taiyo Yuden, TDK, Verbatim, Victor, and
others.
There are three kinds of DVD-RW discs, all with 4.7G capacity. Version
1.0 discs, rarely found outside of Japan, have an embossed lead-in (to prevent
copying of CSS information), which causes compatibility problems.
Version 1.1 discs have a pre-recorded lead-in that improves compatibility.
Version 1.1 discs also come in a “B” version that carries a unique ID in the
BCA for use with CPRM. B-type discs are required when copying certain
kinds of protected video. (See “What Are the Copy Protection Issues?” in
Chapter 1 for more on CPRM; see “What Is BCA?” in Chapter 3, “DVD
Technical Details,” for more on BCA.)