While consumers around the world have enjoyed burning
their own DVDs for a few years now, the inevitable
question of “what’s next” is now
upon the industry. Certainly, blue laser technologies
such as Blu-Ray will one day become affordable and
prevalent; however, consumers today are still very
much in love with DVD. The DVD format is mature, high-quality
content is widely available, and players are low cost
and now installed in approximately 53 percent of U.S.
Dual layer DVD technology is not new. Commonly called “DVD9,” Hollywood
has been churning out major motion pictures on stamped
dual layer DVD Discs for years. How else could they
include the full length movie plus all the bonus materials
commonly found on today’s DVDs? Because dual
layer technology has always been part of the DVD specifications,
dual layer DVD recording on the desktop is the natural
progression of single layer 4.7GB recordable technology.
Dual layer DVD recordable discs offer up to four
hours of high quality MPEG-2 video, or up to 8.5GB
of data on a single-sided disc with two individual
recordable “layers.” Dual layer capable
recorders will have the ability to record on the new
dual layer DVD recordable discs, as well as on traditional
single layer DVD discs and CDs too. Want more? Because
a recorded dual layer DVD disc is compliant with the
DVD9 specification, the discs are compatible with most
consumer DVD players and computer DVD-ROM drives already
installed in the market.
How Are Dual Layer Discs Recorded?
Single-sided dual layer recordable discs are constructed
by one dummy polycarbonate platter base and the other
one that contains a single organic recording layer.
Dual layer recordable discs contain two organic dye
recording layers (termed L0 and L1, respectively) between
dual polycarbonate bases and semi-reflective metal
layers separated by a transparent spacing layer. Single
layer DVDs have a wobbled pre-groove molded into the
polycarbonate base that controls the rotation speed
of the disc and provide the addressing scheme for the
disc. In a dual layer recordable DVD, each recording
layer has its own wobbled pre-groove that controls
rotation speed and addressing for that layer. However,
the entire “table of contents” and system
area of a dual layer recordable disc is contained only
on the first recordable layer (L0).
Layer Continued >