Hardware Reference
In-Depth Information
16 sectors of information repeated 192 times, for a total of 3,072 sectors. Contained
in the 16 (repeated) sectors is information about the disc, including disc category and
versionnumber,discsizeandmaximumtransferrate,discstructure,recordingdensity,
anddatazoneallocation.Theentirelead-inzonetakesupto196,607(2FFFFh)sectors
on the disc. Unlike CDs, the basic structure of all sectors on a DVD is the same. The
buffer zone sectors in the lead-in zone have all 00h (zero hex) recorded for data.
•
Data zone
—The data zone contains the video, audio, or other data on the disc and
starts at sector number 196,608 (30000h). The total number of sectors in the data zone
can be up to 2,292,897 per layer for single-layer discs.
•
Lead-out (or middle) zone
—The lead-out zone marks the end of the data zone. All
the sectors in the lead-out zone contain zero (00h) for data. This is called the middle
zone if the disc is dual-layer and is recorded in opposite track path (OPT) mode, in
which the second layer starts from the outside of the disc and is read in the opposite
direction from the first layer.
ThecenterholeinaDVDis15mmindiameter,soithasaradiusof7.5mmfromthecenter
of the disc. From the edge of the center hole to a point at a radius of 16.5mm is the hub
clamp area. The lead-in zone starts at a radius of 22mm from the center of the disc. The
data zone starts at a radius of 24mm from the center and is followed by the lead-out (or
middle) zone at 58mm. The disc track officially ends at 58.5mm, which is followed by a
1.5mmblankareatotheedgeofthedisc.
Figure11.10
showsthesezonesinactualrelative
scale as they appear on a DVD.
Figure 11.10
Areas on a DVD (side view).
