DVD Demystified

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Introduction
This chapter deals with the family, fundamental formats, and features of
DVD technology, with a focus on DVD-Video. It also explores, explains, and
explodes some of the myths and misconceptions that have grown up around
DVD.
The DVD Family
Chapter 4
The DVD family started off as promisingly as the Brady Bunch. Mr.
Laserdisc and Mrs. CD-ROM produced rotund twins that everyone loved:
DVD-ROM and DVD-Video. Little brother DVD-R came next and got along
well enough despite a case of split personality when he was 2 years old. Like
the sibling squabbles of the Bradys, however, rivalries and frictions soon
popped up. DVD-RAM followed DVD-R but refused to play with the others.
DVD-Audio, after an interminable gestation, was so different from DVD-
Video that at first the two could not play together. Cousin DVD+RW was
ostracized by the rest of the family, even though she tried hard to fit in. And
the young triplets, DVD-Video Recording, DVD-Audio Recording, and DVD-
Stream Recording, were odd enough that it would take the rest of the family
a while to be able to handle them. The happy ending, where differences are
resolved and everyone gets along again, which always came at the end of
every Brady Bunch episode, is much longer in coming for the DVD family.
Figure 4.1 shows the overall relationships between the various members
of the DVD family. DVD-ROM is the base format that underlies everything.
The writable formats are all variations of DVD-ROM, each with its particular
good and bad points. DVD-R can record data once, whereas DVD-RAM,
DVD-RW, and DVD+RW can be rewritten thousands of times. When first
released, DVD-R and DVD-RAM were available for computers only, but by
2001 all recordable formats also were being used in home video recorders.
DVD-R, based on organic dye media similar to CD-R, is generally compatible
with other DVD drives and players. The related DVD-RW format, based on
phase-change technology similar to CD-RW, is also generally compatible
with other drives and players. Just as with CD-R, problems reading DVD-R
and DVD-RW will soon disappear and be forgotten. On the other hand, DVD-
RAM, a concoction of magneto-optical and phase-change technologies, was
not compatible with anything when it was released. It took more than a year
before DVD-ROM drives that could read DVD-RAM discs were released. It