[Ham-Computers] RE: Commercial DVD vs DVD-R

[Hsu, Aaron (NBC Universal)]

Sorry OM,

You asked me of this earlier, but I didn't have a chance to reply.  The
difference is probably in the type of disc used for the copy.

In a duplication house, low-volume copies are probably made on standard
DVD-recordable drives using DVD-Recordable media much like you and I can get
in stores.  Note that this type of copying includes the same caveats of
using recordable media (compatibility problems in some drives, high error
rates, etc).  DVD-Recordable media is more expensive due to the phase-change
dye needed for the write-once capability - commercially made DVD's don't
need this dye as disc was made never to be changed.  Also, Recordable DVD's
(like recordable CD's) are not permanent...they have a limited life span and
slowly self destruct.

High-volume copies are probably made using mass production equipment.  The
disc's are "pressed" using standard DVD media vs "recorded" on
DVD-Recordable media.  The end result is a disc that should be equivalent in
manufacturing quality to a DVD disc and with the same longevity of a DVD
disc (near forever).  They should also be 100% compatible in any DVD drive
or player and will cost much less than copies on DVD-Recordable media.

Commercial mass-producing equipment probably require a "master" or the
equipment needs to be "tooled" - a process that involves a cost.  This
initial cost is why low-volume copies are best done on DVD-Recordable media.
However, once you reach the "break-even" point, it makes more sense to go
with the commercially pressed discs.  Many manufactured products are the
same...small quantities are made by hand or done on a special "one-off"
machine.  Large quantities are made on production equipment tooled
specifically for that item/product.  The "one-off" machine can do many
different types of similar items without much change, but only one at a
time.  The production equipment requires that it be tooled to make one
particular item, but once done can create many in a short amount of time.

BTW, I'm not *that* familiar with how commercial DVD's are made, so some
terms I've used may not be accurate.  I hope, however, that I've properly
conveyed the concepts and didn't just stick a foot in my mouth <g>. 

73,

  - Aaron Hsu, NN6O (ex-KD6DAE)
    {nn6o}@arrl.net
    {athsu}@nbcuni.com
    No-QRO Int'l #1,000,006
    . -..- - .-. .-   ".... . .- ...- -.--"
 

-----Original Message-----
Sent: Thursday, June 23, 2005 9:59 AM
Subject: [Ham-Computers] DBD Terms, The Differences?

	
Hello All, 	
	
Can one of you explain to me what the exact difference between a
"manufactured DVD" and a duplicated -R DVD" is? The duplicated is used for
low quanity and the manufactured, which uses a completely different format
and equipment, for higher quanities, such as more than a thousand.
production	
	
I am wondering why the low quanity production is four times as much money to
have done and why two different formats are needed? 	
	
Thank you.	
	
Duane Fischer, W8DBF	
dfischer at usol.com