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DVD
The DVD platform will soon bring movie theater
excitement into millions of homes. Brighter colors, sharper pictures, and
outstanding audio quality make it a unique home entertainment experience. And
with a 4.7 gigabyte capacity, a standard DVD disc can hold hours of full motion
video and sound.
Chronology
A Technical Triumph
how is DVD different from CD?
For greater data density, there are smaller pits, a more closely spaced track
and a shorter- wavelength red laser. The error correction is more robust. And
thanks to Sony technology, the modulation scheme is more efficient. All this
means that a standard DVD can hold 4.7 gigabytes of data - an amazing seven
times the data capacity of a current Compact Disc! So you'll enjoy
higher-resolution pictures, more channels of digital sound, richer graphics,
and far more multimedia. Not enough? Dual-layer DVDs can hold more than twelve
times the information of a CD on a single side. So there's no need to turn the
disc over.
Hollywood Spectacular
DVD is major news for anyone who owns a television - and anyone who enjoys
movies. Thanks to digital video decoding technology, DVD delivers far and away
the best color, sharpness and clarity in home video. In fact, a DVD picture
approaches the "D-1" TV studio production standard. And thanks to
variable bit-rate MPEG2 compression, it all fits easily onto a single side of a
4-3/4-inch disc. In fact, a single-layer DVD can hold a 2 hour 13 minute movie
with room to spare for Dolby® Digital discrete 5.1-channel digital soundtracks!
Dual-layer, single-sided discs can hold movies more than four hours long. And
because DVD is an optical disc, you get instant access. You can play it
repeatedly without wear and tear. You'll never need to rewind.
Ultimate Multimedia
Digital convergence is erasing the old distinctions between entertainment and
information, recreation and education. So it's the perfect time for Sony
DVD-ROM. With up to 8.5 gigabytes capacity on a single side - it's the optical
disc that gives you more. More on-line capacity for software publishers. More
room for large databases. And high-quality full-motion video for better
interactive games.
DVD-ROM drives are also speed-readers. Even a standard DVD-ROM blasts along at
higher data transfer rates than even the fastest current CD-ROM. Since they're
able to play your existing CD-ROMs, DVD-ROM drives also respect the past. And
with the possibility of DVD-Write Once and DVD-Rewritable, this format is
focused on the future.
Best of all, DVD is supported by the world's leading hardware manufacturers and
software companies. But Sony is involved in every link of the DVD chain: from
manufacturing MPEG2 encoders, laser pickups, disc drives and decoding devices,
all the way to replicating discs and developing content.
Dolby® Digital in the Home
Like the film format, Dolby®
Digital provides separate channels for left, right, and center speakers at the
front; two surround speakers at the sides; and a subwoofer at the listener's
option. As a result, true stereo surround effects can be
achieved for an expanded sense of depth, localization, and overall realism. And
because Dolby® Digital maintains complete separation of the
channels, it is as suited to music-only recordings and broadcasts as it is to
video formats. Thus it has the potential to open up new worlds of multi-channel
sound reproduction.
When it comes to DVD, Sony does it all.
Features
·
A
single standard for the world
·
The
capacity is way up, the size isn't
·
Multiple
layers for various configurations
·
Two
hours of movie on one side
·
The
next step in digital surround sound
The Road from CD to DVD
It is now 14 years since Sony and Philips launched the Compact Disc digital
audio format and gave the world its first taste of digital entertainment. CD
has enjoyed unprecedented success and universal support among music companies
and hardware manufacturers. To date, over 120 million CD Players and 3 billion
CD's have been sold in the United States alone.
From its origins as a music format, Compact Disc has grown to encompass
computer applications (CD-ROM), imaging applications (Photo CD), and video game
applications with products like the Sony PlayStation® system.
Over the years since the introduction, we have seen significant advances in the
enabling technologies that support the Compact Disc. Laser optics, reflective
films, and disc replication have all made major strides. Digital coding and
compression algorithms have become vastly more sophisticated. Moreover,
integrated circuits and drive mechanisms have made impressive advances.
All of these advances came into play when Sony began work on the next
generation of optical media. The goal: vastly increased capacity, with the
ability to feature an entire movie in high-quality digital video on a single
side of a disc.
This was the start of DVD.
A Single Standard for the World
In September 1995, Sony joined nine other companies to create a single, unified
standard for the emerging DVD format. The format enjoys the enthusiastic support
of the world's major electronics companies. As a movie playback format, it
meets the specific and detailed requests of the motion picture industry's
Studio Advisory Committee. As a computer ROM format, it meets the
specifications of the computer industry's Technical Working Group. No other
product has enjoyed such broad international support across so many industries
prior to launch.
·
Like CD, DVD is 120 mm (4-3/4
inches) in diameter.
·
Like CD, DVD is 1.2 mm thick
composed of (2) 0.6 mm substrates bonded together.
·
The new DVD Players will be able
to play the billions of existing music CDs.
·
DVD software can be replicated
using existing CD production facilities with some modifications.
·
Non-contact laser optics means
playback without wear and tear.
·
A disc-based format means the
kind of split-second random access that no tape format can match.
·
As with Compact Disc, DVD will be durable, and tolerant
of dust, dirt and fingerprints.
The DVD standard defines a disc that maintains the overall dimensions, look and
feel of the current Compact Disc. Some of these similarities will be
unmistakable to consumers experiencing DVD for the first time. Others are less
apparent, but equally important to the rapid and successful introduction of DVD.
·
DVD holds seven times the data
of CD: 4.7 gigabytes per single side, as compared to 680 megabytes for CD.
·
DVD offers a dual-layer,
single-side option, for even higher capacity: 8.5 gigabytes on a single side or
17.0 gigabytes on a double-sided disc. Every DVD is a bonded disc, composed of
two 0.6 mm substrates joined together.
Under the surface, of course, DVD reveals some substantial differences.
The Capacity is way Up, The Size Isn't.
CD VERSUS DVD PIT SIZE COMPARISON
Compared to CD, DVD uses smaller pits and a more closely spaced track. The
result is a significant increase in data density. The higher Numerical Aperture
(NA) lens of DVD helps the laser focus on the smaller pits.
Almost every aspect of DVD was developed, refined or
reinvented to achieve the seven-fold increase in data capacity and data
density. Refinements include smaller pit dimensions, a more closely-spaced
track (finer "track pitch"), and a shorter-wavelength laser.
Conventional CD Players and CD-ROM drives use a laser that emits invisible,
infrared light at the wavelength of 780 nanometers. The new DVD Players and
DVD-ROM drives use a laser that emits red light at 650 and 635 nm. The shorter
wavelengths are better suited to reading the smaller, more densely packed pits.
The laser assembly has also been refined with a higher Numerical Aperture (NA)
lens, resulting in a narrower, more tightly focused laser beam.
Even more significantly, DVD's digital modulation and error correction schemes
have been specifically designed to support this increase in capacity. The 8
to16 (EFM PLUS) modulation scheme is highly efficient and ensures backward
compatibility. And the RS-PC (Reed Solomon Product Code) error correction
system is approximately 10 times more robust than the current CD system. Both
of these developments are direct outgrowths of Sony technology.
Multiple Layers for Various
Configurations
The DVD format provides multiple configurations of data layers. Each
configuration providing additional data capacity. The configurations are:
·
Single Side, Single Layer
·
Single Side, Dual Layer
·
Double Side, Single Layer
·
Double Side, Dual Layer
The basic configuration of Single Side,
Single Layer is 4.7 GB of data capacity. This 4.7 GB is "7
times" the data capacity of today’s music CDs and CD-ROMs.
The Single Side, Dual Layer
configuration provides a total of 8.5 GB on one side using an additional 3.8 GB
on the second layer. This is more than "13 times" the capacity of
today’s music CDs and CD-ROMs.
The Double Side, Single Layer
configuration provides a total of 9.4 GB (4.7 on each side). This configuration
provides a little more capacity. However, because half of the data is on the
second side, it requires either flipping the disc or having a DVD Player
capable of two-sided playback.
The Double Side, Dual Layer
configuration provides the maximum capacity of 17GB (8.5 on each side). Again,
because half the data is on the second side, it requires either flipping the
disc or having a DVD Player capable of two-sided playback.
Studio Production Quality
Just as the original CD created a revolution in audio, DVD will raise the
standard for home video picture quality. In fact, picture quality approaches
"D-1," the CCIR-601 TV studio production standard.
DVD delivers far and away the best color, sharpness and clarity in home video,
far surpassing the Laserdisc standard. DVD also offers high resolution, with
exceptional rendering of fine picture detail. Video distortion is extremely
low, which reduces unwanted color "noise."
Because the recording format is component video, as opposed to NTSC composite
video, the pictures are free of the well-known drawbacks of NTSC - artifacts
including dot crawl and cross color distortion. And because DVD is an optical
format, the picture quality doesn't degrade over time and repeated use.
MPEG2 Video Compression
The CCIR-601 digital video standard specifies a video rate of 167 megabits per
second. At this bit rate, the 4.7 gigabyte capacity of a standard DVD could
only store roughly 4 minutes of digital video! Thus, some form of data
compression is required.
DVD takes advantage of a sophisticated compression technology called MPEG2.
It's a set of flexible compression standards, the second to emerge from the
Moving Picture Experts Group (MPEG). Sony is an active participant in the MPEG
proceedings, a primary developer of the MPEG system and a manufacturer of
encoders. This expertise even extends to developing our own MPEG decoding
devices.
MPEG2 works by analyzing the video picture for repetition called redundancy. In
fact, over 97% of the digital data that represent a video signal is redundant,
and can be compressed without visibly harming the picture quality. By
eliminating redundancy, MPEG2 achieves superb pictures at far lower bit rates.
The Bit Rate Fluctuates
As implemented for DVD, MPEG2 encoding is a two-stage process, where the signal
is first evaluated for complexity. Then, higher bit rates are assigned to
complex pictures and lower bit rates to simple pictures, using an
"adaptive," variable bit-rate process. The DVD format uses 4:2:0
component digital video compressed to bit rates with a range of up to 10
megabits per second. Although the "average" bit rate for digital
video is often quoted as 3.5 megabits per second, the actual figure will vary
according to movie length, picture complexity and the number of audio channels
required.
Two Hours of Movie on One Side
Thanks to MPEG2 compression, a single-layer, single-sided DVD has enough
capacity to hold two hours and 13 minutes of spectacular video on a 4-3/4-inch
disc! At the nominal average data rate of 3.5 megabits per second, this still
leaves enough capacity for discrete 5.1-channel digital sound in three
languages, plus subtitles in four additional languages! Including video, audio
and subtitles, the total average data rate is 4.962 megabits per second. And
because it's single-sided, DVD can store all this with no needs to flip the
disc over.
The Next Step in Digital Surround Sound
Movie DVDs released in the United States will be capable of carrying Dolby
Digital™ (AC-3) audio sound tracks with either 2 or 5.1 channels. Unlike Dolby
Pro Logic® coding, Dolby Digital™ (AC-3) multi-channel sound provides five
completely separate (discrete) channels: Left, Center, Right, Left Rear and
Right-Rear, plus a common Subwoofer channel.
Dolby Digital™ (AC-3), which uses a digital bit rate of 384 kilobits per
second, is already well accepted among videophiles and home theater
enthusiasts. As a true digital system, it offers high quality sound, with
outstanding dynamic range, vanishingly low distortion, wide frequency response
and wow & flutter beneath the threshold of measurement.
As an option to Dolby Digital™ (AC-3) sound, DVD also enables producers to
choose 16, 20, 24-bit at either 48 kHz or 96 kHz, CD quality stereo sound with
Dolby Pro Logic® encoding. And to facilitate international distribution of
movie discs, DVD makes possible up to eight languages and 32 sets of subtitles.
The Sony Digital Heritage
Although DVD specifications are the work of many companies, Sony takes
particular pride in the development of the new format. After all, Sony
co-invented the Compact Disc. And the final DVD standards reflect Sony's
expertise in MPEG2 compression, modulation and error correction technology.
In fact, Sony is involved in every link of the DVD
chain: from manufacturing MPEG2 encoders, laser pickups, disc drives and decoding
devices, all the way to replicating discs and developing content.
When it comes to DVD, Sony does it all.
|
Q. |
What is DVD? |
|
A. |
DVD looks like a Compact Disc. But instead of just
playing music, it delivers more than two hours of high-quality video - for
movies, children's programming or music concerts. A single-sided, single-layer DVD can contain up to 133
minutes of video enough to handle 95% of all movies, without the interruption
of flipping the disc over or changing discs. The optical disc technology of DVD completely
outperforms videotape. For example, you can play a DVD hundreds of times,
without picture degradation. You can go from scene to scene in a split second
without rewinding! Because DVDs can deliver more than 500 lines of
horizontal resolution, the picture detail is more than twice as good as a
VCR. DVDs aren't just for the eyes; they are truly music to
your ears. They feature a new audio system: Dolby Digital™ multi-channel
surround sound. Unlike Dolby Pro Logic’ sound, the new system is all-digital.
Separate Left and Right Surround channels deliver pinpoint accurate sound
effects. What’s more, a special bass effects channel brings added realism to
movie sound tracks and music videos. |
|
Q. |
Why do I need a DVD player if I have a VCR? |
|
A. |
Like the evolution from vinyl LP records to Compact
Discs, DVD was designed to be the next generation of home video
entertainment. DVDs offer digital sound and picture, with video resolution
twice as good as your VCR! |
|
Q. |
How durable are DVDs? |
|
A. |
Remember the first time you connected a CD to your
home stereo? The music had no scratching or popping. DVDs do the same for
movies and videos, with quality that won't degrade, even after thousands of
plays. |
|
Q. |
Will DVDs play on my existing television? |
|
A. |
Yes. You can connect a DVD Player to virtually any
existing TV. |
|
Q. |
Do I have to upgrade my system to enjoy DVD? |
|
A. |
No. You can get started with just a DVD Player. Of
course, you can always upgrade later, adding an A/V receiver or Dolby
Digital™ decoder and a six-speaker package. |
|
Q. |
Can I rent DVDs as I do videocassettes? |
|
A. |
Many video rental stores are already offering DVD for
sale and rental. |
|
Q. |
How many movies are currently available on DVD? |
|
A. |
The list is growing every day. It's impossible to keep
a list current. Check our "Titles" area for software links. |
|
Q. |
Can I record on DVD? |
|
A. |
Recordable DVD for computer applications will first
appear late in 1998. Consumer DVD video recorders may become available, but
well into the future. |
|
|
CD |
DVD |
|
Disc diameter |
120 mm |
120 mm |
|
Disc thickness |
1.2 mm |
1.2 mm |
|
Disc structure |
Single substrate |
Two bonded |
|
Laser wavelength |
780 nm (infrared) |
650 and 635 nm (red) |
|
Numerical aperture |
0.45 |
0.60 |
|
Track pitch |
1.6 um |
0.74 um |
|
Shortest pit/land length |
0.83 um |
0.4 um |
|
Data layers |
1 |
1 or 2 |
|
Data capacity |
Aprox. 680 megabytes |
Single layer: 4.7GB x 2 |
|
Reference user data rate |
Mode 1: 153.6 kilobytes/sec |
1,108 kilobytes/sec, nominal |
|
|
Video CD |
DVD-Video |
|
Video data rate |
1.44 megabits/sec |
1 to 10 megabits/sec variable |
|
Video compression |
MPEG1 |
MPEG2 |
|
Sound tracks |
2 Channel-MPEG |
Mandatory (NTSC): |
|
Subtitles |
Open caption only |
Up to 32 languages |
