Chapter 1

92 Everything You Ever Wanted to Know About DVD
layer (a distance of 20 to 70 microns). To reduce interlayer crosstalk, the
minimum pit length of both layers is increased from 0.4 to 0.44 micrometers.
To compensate, the reference scanning velocity is slightly faster,
3.84 meters per second, as opposed to 3.49 meters per second for singlelayer
discs. Longer pits, spaced farther apart, are easier to read correctly
and are less susceptible to jitter. The increased length means fewer pits per
revolution, which results in a reduced capacity per layer.
NOTE: Older versions of Windows that use FAT16 instead of UDF,
FAT32, or NTFS to read a DVD may run into problems with the 4 gigabyte
volume size limit. FAT16 also has a 2 gigabyte file size limit, while
FAT32 has a 4 gigabyte file size limit. (NTFS has a 2 TB limit, so we’re
okay there for a while.)
See “What About Recordable DVDs: DVD-R, DVD-RAM, DVD-RW,
DVD�RW, and DVD�R?” in Chapter 4 for details of writable DVDs. More
info on disc specifications and manufacturing can be found at Disctronics,
Cinram, Panasonic, Technicolor, and other disc replicator sites.
When Did Double-Sided, Dual-Layer Discs (DVD-18)
Become Available?
These super-sized discs are used for data but are not commonly used for
movies. The first commercial DVD-18 title, The Stand, was released in
October of 1999. A DVD-18 requires a completely different way of creating
two layers. A single-sided, dual-layer disc (DVD-9) is produced by putting
one data layer on each substrate and gluing the halves together with transparent
adhesive so that the pickup laser can read both layers from one side.
But in order to get four layers, each substrate needs to hold two. This
requires stamping a second data layer on top of the first, a much more
complicated prospect. Only a few replicators can make DVD-18s, and the
low yield (the number of usable discs in a batch) makes it more difficult and
expensive than making DVD-9s.
What Are the Video Details?
DVD-Video is an application of DVD-ROM, according to the DVD Forum
specification (see “Who Invtented DVD Technology and Who Owns It? Who
Should Be Contacted for Specifications and Licensing?” in Chapter 6,
“Miscellaneous”). DVD-Video is also an application of MPEG-1, MPEG-2,