What is a DVD?
DVD actually doesn't stand for
anything, because the companies who designed it couldn't decide
if it meant,
-
digital video disc
-
digital versatile disc
A DVD is a storage format
capable of holding large amounts of data such as movies. DVD's
look like compact discs 'CDs' because it's physical dimensions
are the same '12cm'.
As the technology has evolved
users have been able to record, erase and re-record data onto
DVDs. This has created many different formats such as DVD+R,
DVD+RW, DVD-RAM, DVD-R, DVD-RW, DVD-ROM discs.
History of the
DVD
The DVD format came about after
another electronics storage standards war, this time between
Philips/Sony and Toshiba. If your not already aware this occured
in the 1980's with the VHS and Betamax battle. This was won by
JVC's VHS standard, and Sony's format Betamax became history. To
avoid a repeat of this disaster the IBM's president united Sony
and Toshiba behind a single standard. After this the
DVD Forum
was founded in 1995. |
The decision was that Toshiba's SD
format would be used, but Sony demanded that two modifications be made
to the tracking technology. And in September 1996 the DVD
specification Version 1.0 was finally released. You may not remember
but the first DVD players and discs were released in,
-
1996 in Japan
-
1997 in United States
-
1998 in Europe
-
1999 in Australia
Of course like most technologies DVD was
extremely expensive, and it took a while before they dropped below the
$200 mark. And by around 2003 VHS players had virtually
disappeared from many shops. Today you will be hard pressed to find
many VHS models in shops.
Terms
|
Terms |
|
DVD |
Short for digital versatile disc or
digital video disc, a type of optical disk technology similar to
the CD-ROM. |
|
DVD-Video |
A video format for
displaying full-length digital movies. |
|
DVD-ROM |
A type of read-only
compact disc that can hold a minimum of 4.7GB (gigabytes), enough
for a full-length movie. |
|
burn |
Slang term meaning
to write data to a CD-ROM or DVD-ROM. |
|
Formats
DVD-ROM
|
DVD-ROM |
Was the
first DVD standard to hit the market and is a read-only format. The
video or game content is burned onto the DVD once and the DVD will run
on any DVD-ROM-equipped device. |
DVD+R and
DVD+RW
DVDs created by a +R/+RW device can be
read by most commercial DVD-ROM players.
|
DVD+R |
Is a recordable DVD format similar to
CD-R.
A DVD+R can record data only once and then the data becomes permanent
on the disc. The disc can not be recorded onto a second time.
|
|
DVD+RW |
Is a re-recordable format similar to
CD-RW.
The data on a DVD+RW disc can be erased and recorded over numerous
times without damaging the medium. |
- These formats are supported by
Philips, Sony, Hewlett-Packard, Dell, Ricoh, Yamaha and others.
DVD-R,
DVD-RW and DVD-RAM
DVDs created by a -R/-RW device can be
read by most commercial DVD-ROM players.
|
DVD-R |
Is a recordable DVD format similar to
CD-R
and DVD+R. A DVD-R can record data only once and then the data becomes
permanent on the disc. The disc cannot be recorded onto a second time.
There also are two additional standards for DVD-R disks: DVD-RG for
general use, and DVD-RA for authoring, which is used for mastering DVD
video or data and is not typically available to the general public.
|
|
DVD-RW |
Is a re-recordable format similar to
CD-RW or DVD+RW. The data on a DVD-RW disc can be erased and recorded
over numerous times without damaging the medium. |
|
DVD-RAM
|
They can be recorded and erased
repeatedly but are compatible only with devices manufactured by the
companies that support the DVD-RAM format. DVD-RAM discs are typically
housed in cartridges. |
- These formats are supported by
Panasonic, Toshiba, Apple Computer, Hitachi, NEC, Pioneer, Samsung and
Sharp.
- These formats are also supported by
the DVD Forum.
DVD+R DL
and DVD-R DL
Dual Layer is more commonly called Double
Layer and can be seen written as DVD+R DL or DVD-R DL.
|
DVD+R DL |
Also called DVD+R9. It is a Dual Layer
writeable DVD+R. |
|
DVD-R DL |
Also called DVD-R9. It is a Dual Layer
writeable DVD-R. |
-
Dual layer
technology is supported by a range of manufacturers including Dell, HP,
Verbatim, Philips, Sony, Yamaha and others.
- As the name suggests, dual layer
technology provides two individual recordable layers on a single-sided
DVD disc.
- The dual layered discs can hold 7.95GB
- The dual layered discs (DVD+R9 and
DVD-R9) can hold 7.95GB and double sided dual layer (called dvd-18) can
hold 15.9GB.
DVD discs can come in a
regional format, and some DVD players can only play DVD discs from a
certain region. The reason for this was to stop DVD's released early in
certain regions being sold and played in other regions. Movies are usually
released months in advance in the USA compared to Europe. So making DVD's
regional stopped DVD's being sold to Europe early.
Codes
|
0 |
No Region |
|
1 |
USA and Canada |
|
2 |
Europe, including France, Egypt, Arabia,
Greece, Turkey, Japan and South Africa. |
|
3 |
Korea, Vietnam, Thailand, Borneo and
Indonesia |
|
4 |
Mexico, Caribbean, Australia and New
Zealand, and South America |
|
5 |
India, Africa, Russia and former USSR
countries |
|
6 |
China |
|
7 |
Unused |
|
8 |
Airlines/Cruise Ships |
|
9 |
Expansion |
HD-DVD
Short for high definition-DVD, a generic
term for the technology of recording high-definition video on a DVD. In
general, HD-DVD is capable of storing between two and four times as much
data as standard DVD.
History
The HD DVD standard was jointly developed
by a group of consumer electronics and PC companies, spearheaded by
Toshiba. It is currently engaged in a format war with the
Blu-ray disc
format for wide adoption as the preferred next-generation optical disc
standard, much as VHS and Betamax competed for the videotape market.
In 2003, the
DVD
Forum decided that they would back the HD DVD to be the
HDTV successor of the DVD. At this meeting they renamed it to
HD-DVD, while it had
been previously called the "Advanced Optical Disc" (AOD).
|
Disc |
Blu-ray Disc |
HD DVD |
DVD ROM |
|
Storage capacity single layer |
25
GB |
15
GB |
4.7 GB |
|
Storage capacity dual layer |
50
GB |
30
GB |
8.5 GB |
|
Storage capacity triple layer |
75
GB |
45
GB |
N/A |
|
Maximum data transfer rate |
54.0 Mbit/s |
36.55 Mbit/s |
11.08 Mbit/s |
|
Video systems (maximum) |
1920x1080 50/60 HDTV |
1920x1080 50/60 HDTV |
720x480 and 720x576 50/60 SDTV |
Compatibility
Backward
compatibility will be available with all HD DVD players,
allowing users to have a single player in their homes to play both HD DVD
and DVD discs.
There
is also a hybrid HD DVD format which contains both DVD and HD DVD versions
of the same movie on a single disc, providing smoother transition for the
studios in terms of publishing movies, and letting consumers with only DVD
drives still use the discs.
DVD
disc replication companies can continue using their current production
equipment with only minor alterations when changing over to the format of
HD DVD replication. Due to the structure of the single-lens optical head,
both red and blue laser diodes can be used in smaller, more compact HD DVD
players.
Note
that rewritable HD DVD media doesn't exist yet, and it's uncertain whether
currently available HD DVD players and recorders will be compatible with
rewritable media.
Sound
| Dolby
Digital |
Is the reigning
standard for surround sound technology, and the common version in most
homes contains 5.1 channels (five primary speakers and a subwoofer).
Dolby Digital supports both Mono and Stereo. |
| DTS |
It stands for 'Digital
Theatre Systems' is an audio encoding format similar to Dolby Digital.
|
-
Most DVD support both
of these formats.
-
Many people claim DTS
sounds better than Dolby Digital, but experts feel it's almost
impossible to compare the two formats.
References
Wikipedia
Webopedia
DVD Explained
|