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DLT (Digital Linear Tape) is used as "source" to send in the
large quantity of data to be mastered into DVD. DLT tape cartridges are
slightly larger than 8mm tape cartridges but smaller than VHS cartridges.
There are different densities of DLT tape with the highest capacities
holding up to 20GB per tape (uncompressed). Other types of tapes and
transfer media are under development to support DVD.
Cutting a full 4.7GB single layer of a DVD disc today at the
fastest encoding speeds available takes over 90 minutes. As the mastering
software and hardware are improved, this time will decrease. Remember, a
full DVD disc could contain up to four mastered layers of information. A
mastering cut must be done for each layer of information put onto a DVD
disc. Therefore, as the number of layers of information increases, so will
the mastering cost and time.
Some of the problems that threaten to delay the quick
acceptance of DVD in the marketplace are the following:
- COPY PROTECTION
- REGIONAL CODING
- LICENSING
- TODAY'S CD-Rs MIGHT NOT PLAY ON DVD DRIVES
Due to the change in wavelength on the playback laser
for DVD players today's CD-Rs might not play on some DVD drives. This
could be a serious problem for the quick acceptance of DVD in the
marketplace. Changing the reflectivity on newly manufactured CD-Rs would
solve this problem. However this would still leave many thousands or
millions of unplayable CD-Rs in the market. Some manufacturers are
planning on putting two laser optical pickups on their new DVD drives. One
would be at the old wavelength and would be able to play today's CD-Rs.
The other would be at the new wavelength and would play DVDs. This would
of course add cost to the drive however it would completely solve this
backward compatibility issue.
The file structure on a DVD will be Micro UDF (Universal
Disk Format) initially combined with ISO 9660. Eventually Micro UDF will
become the standard file format used for DVD. The Micro UDF file format
will extend and modify what is currently possible with ISO 9660.
The decision to standardize on a single high density
digital (video) disc (which has the potential to be a $50 billion a year
market) is very good news for computer, consumer electronics, and
entertainment companies. Until the compromise was reached, DVD projections
were for a slow, limited roll-out, with the new format not really taking
hold until the end of the decade. Now, post-convergence sales projections
are more optimistic.
eDocPublish.com manufactures DVD discs based on the
specification available to date.
eDocPublish.com has a line that
manufactures DVD and DVD-ROM discs. |