DVD Background Information
DVD Features
DVD started as the
Digital Video Disc but now means Digital Versatile Disc or just DVD. It is a
multi-application family of optical disc formats for read-only, recordable and
re-writable applications. The main features of the DVD formats are:
·
Designed from the outset
for video, audio and multimedia, not just audio.
·
All formats use a common
file system (UDF).
·
Digital and analogue copy
protection for DVD-Video and DVD-Audio built into standard.
·
Backwards compatibility
with current CD media. All DVD hardware will play audio CDs and CD-ROMs
(although not all hardware will play CD-Rs or CD-RWs).
·
Up to 4.7 GB read-only
capacity per layer, 8.5 GB per side maximum.
·
Physical dimensions
identical to compact disc but using two 0.6 mm thick substrates, bonded
together.
·
Single-layer/dual-layer
and single/double sided options.
·
Recordable and
re-writable versions are part of the family.
DVD Applications
Despite the success of
the compact disc there has been a clear need for a higher capacity format to
meet additional application requirements.
DVD technology offers an
optical disc with a much larger capacity than the compact disc and is available
as a family of pre-recorded, recordable and re-writable formats to meet the
requirements of the industries and applications mentioned above.
DVD-ROM is beginning to
replace the CD-ROM and provide a new high capacity disc format for the computer
industry. New PCs are now provided with DVD drives instead of CD drives. The
entertainment industry has developed new games consoles (eg Sony's PS2 and
Microsoft's X-Box) which incorporate DVD-ROM drives for more sophisticated and
realistic games applications.
DVD-Video, which was
launched in 1997 in the USA, has become the most successful of all the DVD
formats, as it has proved to be an ideal vehicle for distributing video content
from the movie industry. It can store a full-length movie of high quality video
with surround sound audio on a disc the same size as a CD.
DVD-Audio, which was
launched in 2000, is slowly gathering momentum to become the format for very
high quality, surround sound music, offering the music industry new revenue
opportunities.
DVD-Video and DVD-ROM
hardware and software have been available since 1997. DVD-Audio was launched in
2000. DVD writers and DVD video recorders are now available at affordable
prices.
Recordable formats such
as DVD-RAM, DVD-RW and DVD-R are now being extensively used in PCs for computer
backup and short runs of DVDs and in standalone products such as video recorders
and camcorders.
DVDs can now be unlocked
to make them region free, allowing you to play films from all over the world.
You can learn how to do this by using simple handset codes. To give your player
multi-region capacity, take a look at the rest of this site!
DVD Overview &
Features
DVD, the Digital
Versatile Disc, is a high capacity CD-size disc for video, multimedia, games and
audio applications. Capacities for the read-only disc range from 4.7GB to
17.1GB. DVD discs offer much higher capacity than CDs for high quality video,
audio and software.
The high quality of video
and audio has helped DVD-Video to replace VHS for pre-recorded titles and to
increase the overall video market in most regions. Statistics show that DVD is
growing faster than any other consumer electronics format in the USA and Europe.
PCs with DVD capability
are also selling, but multimedia and games applications of DVD have been slow to
start. The advent of new games consoles using DVD is also helping to stimulate
further sales.
Technical FAQ
They [DVD discs] look like Compact Discs.
What's the big deal?
DVD discs are the same diameter (120mm)
and thickness (1.2mm) as a Compact Disc, but that is where the
similarities end. A single DVD disc has the capability to store up to
13 times the data contained on a CD, on one side! If you factor in
DVD's capability to utilize both sides of a disc for data storage, you
have an information marvel that offers 26 times the power of a Compact
Disc!
That enhanced capability is a
tremendous enabling device. DVD will revolutionize Multimedia,
information retrieval and storage and mobile navigation. DVD will
create new high quality audio standards, impact learning and training
videos, and bring the Cinema experience to Home Entertainment.
How long will DVD movies play before I have
to turn the disc over?
At an average bit rate of 4.5Mbs, a
single sided DVD disc has the playback capability of 133 minutes of
the highest quality audio and video images. That's nearly 92% of all
Hollywood titles ever made!
In fact, a dual layer DVD disc can
provide up to 4 hours of the highest quality audio and video on a
single side of the disc!
Will DVD movies play on my current CD
player?
No, you will require a DVD player that
is equipped to read the pits and lands of a DVD disc and decode the
MPEG-2 data signal.
What is the
digital audio output on the back of my DVD player for?
This connector outputs a digital data
stream that may be sent to an outboard D/A converter for 2 channel
audio processing. More importantly, it may be connected to an audio
receiver equipped with a Dolby AC-3 processor for multi-channel audio
decoding.
What are the
advantages of Dolby? Digital Surround AC-3?
Dolby Digital Surround offers discrete
processing of 5 independent channels ( Left, Centre, Right, Left
Surround, Right Surround, and an additional effects channel that may
be routed to a subwoofer) of audio information. Dolby Digital Surround
provides the producers of movie soundtracks added flexibility and
creativity in the studio that results in more realism, and a "you are
there experience." Each of the 5 Audio channels is a full range
(20-20khz) signal. The discrete nature of Dolby Digital Surround
provides increased clarity (especially critical for dialogue) and
spatial realism. With Dolby Digital Surround, audio images may be
panned across the front of the room; from front to rear; from rear to
front; and even diagonally.
Will DVD discs
wear out, like VHS movies?
No. The picture quality of the DVD disc
is consistent from the first play to the thousandth play. Plus, DVD
discs will not deteriorate over time, are unaffected by magnetic
fields (which can literally erase a VHS cassette) and do not require
rewinding after viewing.
What is an Aspect
Ratio? Why is it important?
Aspect ratio refers to the ratio of
width to height of a television set. Traditional television sets have
a 4:3 aspect ratio. Widescreen television sets have a 16:9 aspect
ratio. Traditional television sets are almost square in appearance;
widescreen displays are more rectangular.
The DVD defines the capability to
display movies in 3 different ways:
- Widescreen, which provides a special
"anamorphic video" signal that, when processed by a widescreen
television set, fills the entire screen and delivers optimum picture
quality.
- Pan and Scan, a version that fills
the screen of traditional 4:3 television sets with an entire
picture, much like watching network movies.
- Letterbox mode, which provides
horizontal bands at the top and bottom to, in essence, create a
widescreen picture in a traditional television set.
Each of the 3 display modes, if
provided by the Hollywood producer, may be selected for viewing if the
viewing device (player or DVD-ROM playback sub-system) is so equipped.
I do not own a
Dolby Digital Surround AC-3 receiver. Can I still enjoy my Home Theater
audio system with DVD?
Yes, every DVD player currently on the
market has analog ( Left and Right ) audio outputs that you can
connect to your Dolby Surround Sound, or Pro-Logic receiver. The
analog audio outputs of your DVD player passes through specially
encoded Dolby Surround Sound signals.
My television set
has Composite and S-Video inputs. What is the best way to connect my DVD
player?
DVD is a format that will provide
significant picture quality advantages when connected to your
television set via the S-Video connectors. Your DVD player must have
S-Video output to take advantage of this capability.
Are there any
other adjustments I should make to my television to take advantage of
S-Video?
Yes. The colour detail signal is so
rich, you will find that you do not need to turn your sharpness
control up when watching DVD. In fact, in many television sets, you
will optimize picture quality by turning the sharpness control off!
Just how good is
the DVD picture?
Based upon pixel resolution, colour
resolution, colour detail, black level reproduction and a virtual lack
of colour noise, the DVD picture is nearly 3 times better than
conventional VHS.
Is DVD picture
quality better than Laserdisc?
Yes. DVD is component video, Laserdisc
is composite video. The DVD picture is characterized by more colour
detail, and colour resolution and contains significantly less NTSC
picture artefacts than Laserdisc. It is generally accepted that a
Laserdisc is capable of producing 400-425 horizontal lines of
resolution. A DVD disc produces in the range of 480-500 horizontal
lines of resolution. A single sided 4.7" (120mm) dual layer DVD disc
can store up to 4 hours of the highest quality audio and video images.
A 12" Laserdisc can only store 60 minutes on a single side. And DVD
movies will play on your computer equipped with a DVD-ROM and
appropriate MEPG decode devices. DVD is the realization of true
cross-platform multimedia.
Is it [DVD]
better than DSS?
Yes. DVD is mastered as CCIR601 4:2:2
digital component video and utilizes 100% MPEG-2 data reduction. DSS,
on the other hand, is 4:1:1 digital component video and features
scaleable compression schemes that vary from MPEG-1 to MPEG-2. In
fact, the digital component video signal of DVD has the capability to
rival the best studio masters.
Do I need a
Widescreen TV to play 16:9 movies?
A DVD-player can be connected to any
television, but with a Widescreen TV you will get the most viewing
enjoyment. With DVD-Video you can gradually build up your own Home
Cinema system with widescreen TV and multi-channel digital surround
sound. DVD-Video supports multiple aspect ratios. Video stored on a
DVD in 16:9 format is horizontally squeezed to a 4:3 (standard TV)
ratio. On Wide-screen TVs, the squeezed image is enlarged by the TV to
an aspect ratio of 16:9.
DVD video players output widescreen
video in three different ways:
- Letterbox (for 4:3 screens)
- Pan & scan (for 4:3 screens)
- Anamorphic or unchanged (for wide
screens)
In widescreen or letterbox mode, if a
movie is wider than 16:9 (and most are), additional thin black bars
will be added to the top and bottom at production time or the sides
will be cropped. Video stored in 4:3 format is not changed by the
player. It will appear normally on a 4:3 screen. Widescreen systems
will either stretch it horizontally or add black bars to the sides.