AC3:
A term synonymous with Dolby Digital, which provides 5+1 Channels of
sound. (see 5.1)
Artiface: Something evident in
a picture that was not there to begin with. For example, when you watch an
AVI or Quicktime movie on your computer, you often see blocky picture
elements. Those blocks are artifacts because they were not a part of the
original picture. On DVD, artifacts are usually a symptom of poor mastering,
poor playback equipment, or improper adjustment of your television monitor.
Make sure to calibrate your picture using a test disc like Video Essentials
if you feel you are seeing artifacts.
5.1: Shorthand notation for a movie that has five
full-range channels of sound and one channel of subwoofer effects. The number to
the left of the dot is the number of full range channels and the number to the
right of the dot signifies the presence of the dedicated subwoofer channel (also
known as LFE). A movie in 5.0 sound has five full range channels and no
subwoofer track; a movie in 2.0 sound can be encoded in Dolby Surround or can
just be stereo.
Chapter Index: A DVD movie Chapter is similar to a book chapter or a CD
track. The Chapter Index allows you to jump to any scene included in the menu
(see Interactive Menus.) Your remote should have a button to display the menu.
DVD-ROM menu displays vary; sometimes it is shown below the movie window, and
sometimes you have to access it through a mouse-click or keystroke. Most menus
consist of anywhere between t and 36 scene depictions. These Chapters are
displayed as still frame graphics, thumbnails of scenes in action, or simply
test links. You can select the Chapter with your remote arrow keys and jump to
the chosen scene.
Copy Protection: Both discs and players come equipped with hardware
mechanisms to prevent the illegal copying of DVDs. You will not be able to copy
the movie to a VHS tape, your computer’s hard drive or any other data –recording
device.
Day and Date: Most major movie studios release
almost all movies on the same street date as the VHS Video.
Digital Remastering: Stated simply, the quality of the DVD is much higher
than that of the same movie on VHS.
DIVX: DIVX is a DVD disc which has been encoded so that you can buy it
for $4.50 typically, watch it twice within 48 hours (on a specially equipped
player) and then throw it away. Also if you wanted to watch it at a later date
you could pay an additional fee and watch it again and again with a fee for each
play. This format was available from approvable June of 1997 until July of 1999
and then the backers (mainly Circuit City) quit manufacturing these.
Dolby Digital: An advanced compression method that
allows 1 to 5.1 channels of sound to be to be presented on disc. This is the
standard sound format that is required on DVD, and it will also be used in
future HDTV broadcasts. Audio equipment with a Dolby Digital decoder is
required for playback, although all DVD players will "downmix" the
signal into two-channel surround if you don't have the DD equipment.
DTS: Digital Theater Systems; a competing multi-channel
audio format that also encodes 1 to 5.1 channels of sound for playback on
equipment that has a DTS decoder. Common in movie theaters, on laserdisc, and on
compact disc, but there are no DTS DVD's yet. A DTS-compatible DVD player will
be required for playback of the DTS signal, and only select recent DVD player
have this capability.
DVD: Digital Video Disc, or Digital Versatile Disc (or just DVD...the
acronym is easier to say, anyway!) a disc the same size as a
Music CD or Computer CD which plays Movies or hold a large amount of data. Must
be played on a player or computer drive designed to play DVD.
DVD, More Detail: DVD which once stood for Digital Video Disc or Digital
Versatile Disc, is the next generation of optical disc storage technology. It's
essentially a bigger, faster CD that can hold video as well as audio and
computer data. DVD aims to encompass home entertainment, computers, and business
information with a single digital format, eventually replacing audio CD,
videotape, laserdisc, CD-ROM, and perhaps even video game cartridges. DVD has
widespread support from all major electronics companies, all major computer
hardware companies, and all major movie and music studios now support and
release almost all movies day and date with the VHS
Video.
DVD, What are the features of DVD-Video?
- Over 2 hours of high-quality digital video (over 8 on a double-sided,
dual-layer disc).
- Support for widescreen movies on standard or widescreen TVs (4:3 and 16:9
aspect ratios).
- Up to 8 tracks of digital audio (for multiple languages, DVS, etc.), each
with as many as 8 channels.
- Up to 32 subtitle/karaoke tracks.
- Automatic "seamless" branching of video (for multiple story
lines or ratings on one disc).
- Up to 9 camera angles (different viewpoints can be selected during
playback).
- Menus and simple interactive features (for games, quizzes, etc.).
- Multilingual identifying text for title name, album name, song name, cast,
crew, etc.
- "Instant" rewind and fast forward, including search to title,
chapter, track, and timecode.
- Durable (no wear from playing, only from physical damage).
- Not susceptible to magnetic fields. Resistant to heat.
- Compact size (easy to handle, store, and ship; players can be portable;
replication is cheaper).
- Noncomedogenic.
Note: Most discs do not contain all features (multiple audio/subtitle tracks,
seamless branching, parental control, etc.), as each feature must be specially
authored. Some discs may not allow searching or skipping.
DVD, What's the quality of DVD-Video? DVD has the capability to produce
near-studio-quality video and better-than-CD-quality audio. DVD is vastly
superior to videotape and generally better than laserdisc (see 2.8.).
However, quality depends on many production factors. As compression experience
and technology improves we will see increasing quality, but as production costs
decrease we will also see more shoddily produced discs. A few low-budget DVDs
will even use MPEG-1 encoding (which is no better than VHS) instead of
higher-quality MPEG-2.
DVD-ROM Compatible: These discs are playable on your computer’s DVD-ROM
drive, if equipped with a hardware or software MPEG-2 decoder.
DVD: How should I clean and care for DVDs? Since DVDs are read by a
laser, they are resistant—to a point—to fingerprints, dust, smudges, and
scratches. However, surface contaminants and scratches can cause data errors. On
a video player, the effect of data errors ranges from minor video artifacts to
frame skipping to complete unplayability. So it's a good idea to take care of
your discs. In general treat them the same way as you would a CD.
Your player can't be harmed by a scratched or dirty disc, unless there are
globs of nasty substances on it that might actually hit the lens. Still, it's
best to keep your discs clean, which will also keep the inside of your player
clean. Never attempt to play a cracked disc, as it could shatter and damage the
player. It probably doesn't hurt to leave the disc in the player (even if it's
paused and still spinning), but leaving it running unattended for long periods
of time is not advisable.
In general, there's no need to clean the lens on your player, since the air
moved by the rotating disc keeps it clean. However, if you commonly use a lens
cleaning disc in your CD player, you may want to do the same with your DVD
player. I recommend only using a cleaning disc designed for DVD players, since
there are minor differences in lens positioning.
Handle only at the hub or outer edge. Don't touch the shiny surface with your
popcorn-greasy fingers.
Store in a protective case when not in use. Do not bend the disc when taking
it out of the case, and be careful not to scratch the disc when placing it in
the case or in the player tray.
Make certain the disc is properly seated in the player tray before you close
it.
Keep away from radiators/heaters, hot equipment surfaces, direct sunlight
(near a window or in a car during hot weather), pets, small children, and other
destructive forces. Magnetic fields have no effect on DVDs.
Coloring the outside edge of a DVD with a green marker makes no difference in
video or audio quality. Data is read based on pit interference at 1/4 of the
laser wavelength, or less than 165 nanometers. A bit of dye that on average is
more than 3 million times farther away is not going to affect anything.
DVD, Cleaning and repairing DVDs: If you notice problems when playing
a disc, you may be able to correct them with a simple cleaning.
- Do not use strong cleaners, abrasives, solvents, or acids.
- With a soft, lint-free cloth, wipe gently in only a radial direction (a
straight line between the hub and the rim). Since the data is arranged
circularly on the disc, the micro scratches you create when cleaning the
disc (or the nasty gouge you make with the dirt you didn't see on your
cleaning cloth) will cross more error correction blocks and be less likely
to cause unrecoverable errors).
- Don't use canned or compressed air, which can be very cold and may
thermally stress the disc.
- For stubborn dirt or gummy adhesive, use water, water with mild soap, or
isopropyl alcohol. As a last resort, try peanut oil. Let it sit for about a
minute before wiping it off.
- There are commercial products that clean discs and provide some protection
from dust, fingerprints, and scratches. Cleaning products labeled for use on
CDs work as well as those that say they are for DVDs.
If you continue to have problems after cleaning the disc, you may need to
attempt to repair one or more scratches. Sometimes even hairline scratches can
cause errors if they just happen to cover an entire ECC block. Examine the disc,
keeping in mind that the laser reads from the bottom.
WE REPAIR DVD, PLAYSTATION, AND ALL OPTICAL DISCS
... ASK FOR PRICES.
Interactive Menus often consist of the Chapter Index
and links to other features on the disc. Selecting them on the Menu can
instantly access these extras. The extras may include performers’ bios, movie
previews, behind the scenes and virtual playrooms. Interactive Menus may also
allow you to select certain settings for the movie, such as language.
Generations of DVD: What's the difference between first, second, and third
generation DVD? There is no good answer to this question, since you'll get a
different response from everyone you ask. The terms "2nd generation"
and "3rd generation" are used refer both to DVD-Video players and to
DVD-ROM drives. In general, they simply mean newer versions of basic DVD
playback systems. The terms haven't been used (yet) to refer to DVD systems that
can record, play video games, or so on.
According to some people, second-generation DVD players came out in the fall
of 1997 and third-generation players are those that came out in the beginning of
1998. According to others, the second generation of DVD will be
"high-definition" players that won't come out until 2003 or so. There
are many confusing variations between these extremes, including the viewpoint
that DTS-compatible players or DIVX players or progressive-scan players
constitute the third generation.
Things are a little more clear cut on the PC side, where second generation
(DVD II) usually means 2x DVD-ROM drives that can read CD-Rs, and third
generation (DVD III) usually means 5x (or sometimes 2x or 4.8x or 6x) DVD-ROM
drives, a few of which can read DVD-RAMs, and some of which are RPC2 format. See
section 4.2
for more speed info.
LFE: Low Frequency Effects; name given to the dedicated subwoofer
channel in Dolby Digital and DTS audio formats.
Multi-angle: What better way to enjoy an adult movie than play
cameraman? You choose the angle while you watch. Some DVDs offer nine different
viewing angles. Multi-angle is the ultimate use of DVD technology. This feature, however, does not mean that you may change angles throughout
the entire movie. Multi-angle scenes have an icon on the screen to let you know
that you can change angles.
Parental Lock: Allows you to deny playback of discs or scenes through
player mechanisms supported by disc specific content.
Recording on DVD:
Short Answer: No. (Not in this century, however this century is almost over.)
Long answer: The minimum requirement for reproducing audio and video on DVD is
an MPEG video stream and a PCM audio track. (Other streams such as Dolby Digital
audio, MPEG audio, and subpicture are not necessary for the simplest case.)
Basic DVD control codes are also needed. At the moment it's difficult in real
time to encode the video and audio, combine them with DVD-V info, and write the
whole thing to DVD. Even if you could do all this in a home recorder, it would
be extremely expensive. Prices for DVD production systems are dropping from
millions of dollars to thousands of dollars, but they won't be in the <$500
range for home use for several years yet. In June 1997, Hitachi demonstrated a
home DVD video recorder containing a DVD-RAM drive, a hard disk drive (as a
buffer), two MPEG-1 encoders, and an MPEG-2 decoder. No production date was
mentioned. It's possible the first home DVD recorders will require a digital
source of already-compressed audio and video, such as DBS.
Other obstacles: Price of blank discs initially will be $30 and up. The first
generation of recordable media will hold less than 3/4 as much as prerecorded
discs. Real-time compression requires higher bit rates for decent quality,
lowering capacity even more. MPEG-2 compression works much better with
high-quality source, so recording from VHS or broadcast/cable may not give very
good results (unless the DVD recorder has prefilters, which raises the cost).
[Glossary,
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