DVD
FAQ
DVD
Glossary
Building
a home theatre
DVD
FAQ
DVD-Audio
FAQ
DVD
Basics
Subtitles
Explained
Interfacing
Explained
Monitor
Calibration
Digital
Projection
Toshiba
3108 Firmware upgrade guide
What
is Anamorphic widescreen?
What
is 3:2 pulldown?
Surround
THX Part I
Path
to Surround EX THX Part II
Set
up proceedure for THX EX Surround Part III
Psuedo
Surround EX Part IV
The
THX Overview Part V |
DVD
FAQ
These may be some of the
most simple, but commonly asked questions about the DVD medium.
- Why Are DVD's Gold?
Most DVD's are gold because they contain two layers of disc surface.
These DVD's (Dual Layer/Single Sided) are called DVD-9, they hold all
the data on one side of the disc in two layers. The gold appearance
is due to the first layers metal. Most DVD's first layer (closet to
the centre) have a aluminum layer for the data, these DVD-9's have two
layers, so the second layer is made with a semitransparent layer so
the DVD player can focus to either layer.
- Why are some DVD's dual sided?
Some DVDs which are double sided are of the earlier generation. These
are DVD-10, DVD-14 or DVD-18, depending whether they are single sided,
mixed layers, or dual layers on either side. Older DVD's such as new
ones which first came out were single sided single layers, and didn't
have a very good picture quality because of the lack of space.
- How Much Data can a DVD Hold?
Standard DVD-9 discs which have two layers on one side are roughly 9.37Gb
in size. The single layer discs (DVD-5) are only 4.7Gb. The reason the
DVD-9 discs are slightly smaller than twice the DVD-5, is that at the
end of the disc the DVD player must be able to realign to the other
layer, that is, have enough space to get to it, in this way it eats
up less than a mm on the disc but a whole 30Mb.
- How much video can you fit on a DVD?
Well for the various discs it usually has around 2 hours of normal compression
video for a single layer. That means a DVD-5 (Single Layer Single Side)
has over two hours, a DVD-9 has twice that of approximately 4 hours.
While the DVD-10s have 4.5 hours, and anything up to 8 hours if you
have two layers and two sides on DVD-18.
- How Are DVD's Different To CD's?
CD's use tracks of data which stretch for over 33 miles around the
disc. DVD's have, quite simply, smaller tracks. No-one has published
a length of the tracks as yet. These smaller tracks require a finer
laser assembly, but the amount of data which can be taken at once is
much higher.
- What are DVD-ROMs?
DVD Roms are the equivalent of a CD-ROM to a CD. These DVD-ROMs
are basically the same disc, in that you can have dual layer, single
sided, single layer double sided etc, but they have much more complex
things on them which a computer or games console can understand. Basically
you can hold files and folders on them. The amount of data is the same.
- Are DVD's More Robust That CD's?
Yes and no. You see DVD's are made from (usually) two layers, in
that, they are glued together in the development process, this means
if you bend them or something, they could separate, this could damage
one of the layers. On the other hand if you scratched the top edge of
the disc (label side) you will only be damaging the top layer, the other
layer will probably be still usable.
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