 What
makes DVDs so much better than VHS videocassettes?
What's
the difference between Dolby Surround, Dolby Digital 5.1, and
DTS?
What
is a dual-layered DVD?
What's
the difference between widescreen and anamorphic?
What
about the pan-and-scan and full-frame (or full-screen)
formats?
What's
the difference between "close-captioned" and
"subtitled"?
Why
do some DVDs require flipping from one side to the
other?
What's
the difference between PAL and NTSC?
What
is region encoding?
What
is Regional Code Enhancement (RCE)?
Can
I play imported DVDs on my player?
What
is progressive-scan technology?
How
can a DVD offer parental control or parental locking of potentially
offensive material?
Can
I play DVD-ROM materials on my DVD player?
What's
a "fully loaded DVD"?
What
does "THX certified" mean?
What
is "Infinifilm"?
What
is "Superbit"?
What
are test discs?
What
are "Easter eggs"?
What makes DVDs so
much better than VHS videocassettes?
Two words: data
capacity. Although a DVD (short for "digital versatile disc" or "digital
video disc") looks identical to a compact disc, the format uses much
smaller and more compact digital "pits" in its physical structure. And
compared to a CD, it is capable of storing up to 25 times as much digital
information--up to 17 gigabytes of data on a double-sided, dual-layered
DVD (see the following question for more on sides and layers). Most movies
can easily fit onto a single-sided, single-layer DVD (which can hold 4.7
gigabytes of data), allowing ample room for additional soundtrack options,
language tracks, filmmaker commentaries, and subtitles, as well as bonus
features such as deleted scenes, featurettes, biographies, and interviews.
And because DVD is an all-digital format, it offers superior sound clarity
and picture resolution, which are enjoyable even on a modest budget but
can be best appreciated with a state-of-the-art home-theater system.
What's the
difference between Dolby Surround, Dolby Digital 5.1, and
DTS?
Dolby Surround (also Dolby Pro Logic) is the
surround-sound format most commonly found on video cassettes and laser
discs (and many DVDs). It refers to a nondiscrete sound format in which
four channels (left, right, center, and surround) are combined into two
channels and decoded back (by Pro Logic receivers) into the original four
surround channels of your home-theater speaker system.
Dolby Digital 5.1 is a discrete-channel surround-sound format
consisting of five distinctly separate channels (left front, left rear,
right front, right rear, and center), plus a subwoofer channel (the .1 in
5.1) to provide deeper, fuller bass. And while not all DVD movies offer a
Dolby Digital 5.1 soundtrack, an increasing number of them do, and you
will definitely notice and appreciate the difference. (Side note: Dolby
Digital AC-3, a sound process introduced in the laser disc format,
translates original two-channel stereo sources into simulated 5.1-channel
output. It is less frequently used on DVD.)
DTS (Digital Theater Systems) is an impressive digital surround-sound
system first introduced in theaters with the release of Jurassic
Park in 1993. DVDs encoded with a DTS soundtrack require a DVD player
and stereo receiver equipped with DTS-processing capability. Preferred by
avid videophiles, DTS demands more data space on a DVD (often sacrificing
bonus features), but many believe the audio quality to be superior to that
of Dolby Digital 5.1-channel surround sound.
What is
a dual-layered DVD?
A DVD can hold digital information on
both sides of the disc and in two sandwiched layers on each side. A
dual-layered disc can, for example, offer a movie in both widescreen and
full-screen (or pan-and-scan) formats, and your DVD player can switch from
one layer to another with a barely perceptible interruption in playback.
Dual-layered DVDs are also useful for holding longer films (such as
Titanic and Saving Private Ryan) or video games that exceed
the capacity of a single layer.
Most DVDs will be properly labeled to indicate if they are
dual-layered. (You can also identify a dual-layered DVD by its
golden-colored data side, as opposed to the shiny silver of a
single-layered disc.) There are two types of dual-layered DVDs--PTP and
OTP (also known as RSDL). The PTP (or "parallel track path") configuration
allows a DVD player's laser to switch easily from layer to layer to access
features like multiple menus, pop-up information, and other special
effects. The OTP (for "opposite track path") configuration is more
commonly referred to as RSDL (for "reverse spiral dual layer"), meaning
that the DVD laser reads the first (top) layer outward from the center of
the disc, then switches to the second (bottom) layer and continues to read
the disc inward from the outer edge. On most DVD players, viewers will
experience a slight pause as the player's laser switches from the top to
bottom layer. In most cases, this pause is very brief and should not
compromise the viewing experience.
What's the
difference between widescreen and anamorphic?
These terms
are often confused, but they're not interchangeable. On a standard
widescreen DVD, the disc is encoded with both the widescreen movie and the
black bars (at the top and bottom of the picture) that are necessary to
properly fit the movie onto a standard 4:3 ratio TV screen. (In other
words, precious data storage is required to generate the black bars.) On
an anamorphic DVD, the widescreen movie is compressed to fit a standard
4:3 TV screen, then decompressed by your player, which generates the black
bars at top and bottom to accommodate the widescreen image. Anamorphic
widescreen is best appreciated by those who own widescreen (16:9) video
monitors, because this allows the entire anamorphic image to fill the
screen at full resolution, with no black bars. (Consequently, the issue of
widescreen vs. anamorphic will become less important as widescreen video
monitors become the accepted norm.)
What about the
pan-and-scan and full-frame (or full-screen) formats?
The
pan-and-scan technique is used to fit widescreen movies onto a standard
4:3 TV screen, so named because the image is often cropped (sacrificing
picture detail from the edges) and then "panned" across to reveal actors
or details that don't fit into the narrower frame. Fortunately, this
method has grown less common as DVD has offered more widescreen viewing
options. The full-frame format is used for films (often but not
exclusively older films) that were shot in the 4:3 screen ratio (or, more
accurately, the 1.33:1 aspect ratio most common in Hollywood's golden
age). On home video and DVD, these films actually include some frame
detail that would normally be masked off in theatrical exhibition, but
you're seeing essentially the same image shown in theaters. Full-frame can
also refer to a film (for example, Stuart Little) that has been
reformatted (often but not always with panning and scanning) from its
theatrical format (typically 1.85:1) to fill a standard TV screen.
What's the
difference between "close-captioned" and "subtitled"?
Simply
put, closed captions consist of onscreen text specifically intended for
hearing-impaired viewers, and they provide scene- and character-specific
references to sound (e.g. "phone rings" or "crowd laughing") and music, in
addition to dialogue. In contrast, subtitles are just as you would see on
a foreign-language film, i.e., direct transcriptions or translations of
spoken dialogue only. On most DVDs, closed captions and subtitles are seen
only when they are selected as options from a specified onscreen menu.
Why do some DVDs
require flipping from one side to the other?
"Flippers" are
DVDs that divide their content over both sides of the disc, resulting in
actual interruption of playback. They are relatively rare, but they still
exist (the first DVD release of GoodFellas is a regrettable
example). Although dual-layered DVDs are capable of holding four hours of
material on each side, some DVDs favor two-sided configuration (allowing
less data compression) over one-sided, dual-layered formatting.
Fortunately, data compression has improved, and one-movie "flippers" are
now exceedingly rare. (Other discs, such as the four-disc set of the
original Outer Limits TV series, maximize their capacity with
dual-layering on both sides, but none of the content is compromised or
interrupted by this configuration, hence they are not, strictly speaking,
"flippers.")
What's the difference between PAL
and NTSC?
There are two television display systems in
commercial use: PAL (common in Europe and parts of Asia) delivers a
scanning/frame rate of 25 frames per second, while NTSC (used in the U.S.
and Canada) delivers a scanning/frame rate of 29.97 frames per second.
Currently there are no DVD players that convert from PAL to NTSC or vice
versa. However, many PAL DVD players are able to display NTSC video on
televisions that support what is known as the 60-Hz PAL system. For all
DVD players in the U.S. and Canada, NTSC is the exclusive system in use.
(For more information, see our video
and DVD formats page.)
What is
region encoding?
Because DVD is subject to the same issues
of piracy and market sharing that govern the entire video industry, region
encoding was introduced to set geopolitical boundaries for compatibility
of DVDs and players. For instance, a DVD encoded for Region 1 can be
played only on a Region 1 (U.S. and Canada) DVD player.
There are six land-based global DVD regions, and two other
non-geographical regions (one for "reserved" purposes and one for
international venues like airplanes and cruise ships). DVD manufacturers
can encode their product to play in any combination of regions. The vast
majority of DVDs are Region 1 or 2 compatible, and many DVDs are "all
region"--suitable for playback on any player, anywhere. (For a complete
chart of international DVD regions, see our video
and DVD formats page.)
While numerous methods have emerged to illegally bypass region encoding
with "hacked" DVD players capable of playing DVDs from any region, movie
studios have also increased their efforts to protect their regional
copyrights with advanced DVD security coding.
What is Regional Code Enhancement
(RCE)?
Regional Code Enhancement (RCE) is different from
region encoding. Introduced by several major studios in 2000, RCE is
digital code added to Region 1 DVDs (for use in the U.S. and Canada) to
prevent them from being played on a "region-free" DVD player. (This was
primarily intended to curtail the use of region-free players in Region 1.)
A disc with RCE will automatically check a DVD player's region code
setting, and if the disc detects a region-free player, it will refuse to
play (typically accompanied by an onscreen warning). In the interest of
copyright protection and market-share equity, RCE was introduced to ensure
that DVDs released in each region will play only on DVD players sold in
the same designated region.
Can I play imported DVDs on my
player?
The short answer is, probably not. The vast majority
of DVD users in North America own Region 1 DVD players that will
not play imported DVDs. Imported DVDs (i.e. DVDs with different
region coding than the region you're living in) will play only on a
"region-free" DVD player, or a player that has been set (or switched) to
play DVDs from that specific region. Region-free DVD players are not sold
through traditional retail markets.)
What is progressive-scan
technology?
For use with HDTV-enabled
televisions, a progressive-scan DVD player provides a superior,
filmlike picture by creating its images differently than conventional
televisions, which use "interlaced scanning." The conventional process
creates its picture by drawing around 400 horizontal lines twice per
frame: once for the even-numbered lines and once for the odd-numbered
lines, interlacing about 30 times per second. Progressive-scan DVD players
scan from top to bottom in one fluid pass, making it harder to discern a
picture's individual scan lines, which increases resolution while
minimizing distortion and flickering. See
all progressive-scan DVD players available at Amazon.com.
How
can a DVD offer parental control or parental locking of potentially
offensive material?
DVDs encoded with the parental lock
feature can be edited to skip over offensive or adult-oriented material
during playback--sort of like turning an R-rated movie into a PG-13, and
so on. If a DVD is encoded with this capability (check the packaging to
make sure), your DVD player's internal rating system can be set to
different levels of parental control, typically accessed via the player's
set-up menu. (For example, the parental lock feature on the Galaxy
Quest DVD can be used to automatically edit out brief use of mature
language and a violent scene involving frightening aliens.)
Can I play DVD-ROM materials on
my DVD player?
Probably not. Most DVD players are not able
to access DVD-ROM materials, which are coded differently for use (in most
cases) on a personal computer. (This is most often because DVD-ROM
features include materials accessible only on the Internet.) As DVD
players, computers, and TV monitors continue to become compatible or
hybrid components, the ability to access DVD-ROM content will become more
flexible from platform to platform.
What's a
"fully loaded DVD"?
Fully loaded is simply a phrase
coined by Amazon.com (and adopted elsewhere) to indicate that a DVD
contains an abundance of bonus features and supplemental materials. There
are different varieties of fully loaded DVDs, but they all offer the same
added value of additional content to enhance the main feature (i.e. a
movie, documentary, etc.). See
Amazon.com's Fully Loaded DVD Store.
What
does "THX certified" mean?
Many people mistakenly believe
that THX is an audio format, but it's not. Rather, THX is a patented
quality-control program created by Lucasfilm to ensure consistently high
quality in acoustics and sound systems approved for theatrical and
home-theater use. If you see the THX logo on a DVD, it means that the
audio tracks on the disc have been subjected to stringent THX standards
throughout the mastering process and will perform best on home-theater
systems using THX-certified equipment. If your home theater does not
include THX-certified equipment (amplifier, speakers, etc.), the high
standard of THX cannot be fully appreciated.
What is
"Infinifilm"?
Infinifilm DVDs were introduced in 2001 by New
Line Home Video to promote its most feature-enhanced titles. Infinifilm is
a trademarked name for New Line DVDs with such advanced features as
pop-ups that direct the viewer to bonus features and supplemental
materials, readily accessed during playback of a movie. Essentially,
Infinifilm DVDs use their uniquely presented capabilities to exploit the
versatility of the DVD format. The pop-up option is now used by other
studios to access DVD extras. See a list of Infinifilm
DVDs available at Amazon.com.
What is
"Superbit"?
Superbit DVDs were first offered by Columbia
Home Video in 2001, and Superbit is an exclusive Columbia trademark.
Essentially, Superbit DVDs reserve all of their data storage capacity for
movies that have been digitally mastered at a higher bit-sampling rate,
thus requiring less compression of the data. Bonus features, animated
menus, and other supplemental materials are sacrificed in favor of
best-available quality of picture and sound. Additional language tracks
are also sacrificed in favor of one DTS audio track. The subtle advantages
of Superbit DVDs are best enjoyed on high-end home theater systems with
DTS capability and progressive-scan monitors (which further enhance
picture quality). See a list of Superbit
DVDs available at Amazon.com.
What are
test discs?
Test discs are DVDs specifically designed to
optimize the audio and video performance of your home-theater system.
These discs adhere to the stringent standards of the audio and video
industries, providing test materials (color bars, sound checks, contrast
charts, etc.) and detailed instructions, guiding home-theater enthusiasts
to adjust their systems, according to exacting industry tests, to achieve
their maximum potential with the DVD format. Examples of these highly
specialized (and typically higher-priced) DVDs include Ultimate
DVD Platinum and Sound
& Vision Home Theater Tune-Up.
What are
"Easter eggs"?
As their name implies, Easter eggs are hidden
surprises, frequently disguised as mysterious logos, symbols, or unlabeled
buttons on a DVD content menu. An Easter egg can be any kind of bonus
feature or supplemental material that is not specifically listed in a
DVD's table of contents. Because they are not identified in any obvious
way, they must be discovered by using the DVD remote to jump around on
menus where they might be hidden. These eggs can include something as
trivial as an outtake or as essential as a completely different version of
the film. The only way to find them is to thoroughly locate and select all
of the functional buttons--labeled or not--on a DVD's menus.
Jeff Shannon is a Seattle-based freelance writer
focusing primarily on films and filmmakers. |
