By the time DVD ("Digital Video Disc" or "Digital Versatile Disc")
was introduced to the American public in March 1997, years of research and
development had preceded its arrival as the "next generation" format of home
entertainment. Consumer electronics manufacturers and movie studios established
an industry-wide DVD-video standard in 1996; and by the end of 1997, DVD
players had set sales records and well over 500 DVD movie titles had been
released, with the rate of new releases rapidly increasing from that point
forward.
A DVD is identical in thickness (1.2 millimeters) and diameter (120
millimeters or 4.7 inches) to a standard Compact Disc, but that's where the
similarities end. The DVD's storage capacity is seven times that of a CD, with
a 4.7-gigabyte capacity on a single-side/single-layer DVD. That's the
data-storage equivalent of a 133-minute movie, thus allowing 95 percent of all
movies to fit comfortably on a single-layer DVD, eliminating the need for
"flipping" the disc and leaving extra room for multiple audio, language, and
subtitle tracks; bonus materials; menu screens; and other features unique to
DVD. This capacity is nearly doubled (8.5 GB) on a single-side/dual-layer DVD,
and quadrupled (17 GB) on a double-side/dual-layer DVD, allowing DVD to
flourish not only as a movie-lover's format, but as an amazingly flexible
medium (DVD-ROM) for high-definition computer games and multimedia
applications. In short, this makes DVD the home entertainment and multimedia
format of the new millennium.
Why should I bother with DVD?
Don't worry--you won't have to trash your VCR if you don't want to.
But the vastly improved audio and video quality of DVD, along with its
durability and flexibility (no rewinding, instant scene access, etc.) makes VHS
pale in comparison. You don't need an upgraded home-theater system (unless DVD
makes you want one!); and affordable DVD players are compatible with CDs, while
some "combo" models allow the playback of DVDs, CDs, and laserdiscs. With all
major movie studios now supporting the format, the selection of current and
classic movies on DVD (along with music videos, opera, documentaries ... you
name it!) is rapidly expanding, along with outlets for DVD sales and rentals.
From big screen to little disc (a basic primer)
Videophiles and laserdisc loyalists will debate the pros and cons of
DVD for years, but one thing is certain: the process of transferring a movie to
DVD is highly advanced and designed to deliver the highest quality of audio and
video available. For every video format (VHS, laserdisc, and DVD), the process
begins with "telecine" (TEL-a-sin-ee), but the procedures for DVD adhere to
much higher standards. The telecine process begins when light is passed through
the film (frame by frame, with exacting precision) and strikes an array of
semiconductors that convert the light into electrical signals. That information
is then digitally transferred to High Definition video (HD), which is capable
of picture resolution nearly equal to that of the original film.
The HD master can be color-corrected and further checked to match the
original film (a process often involving the film's director and
cinematographer). Then its massive data capacity must be compressed via MPEG-2
encoding (developed by the Motion Picture Experts Group, or MPEG), which
produces a varying rate of transferred data to exploit similarities from one
film frame to the next. Less data is required for redundant details while more
data is reserved for complex details such as rain, smoke, crowd scenes, etc.
(This process leads to image-quality debates between laserdisc and DVD
fanatics, due to the idiosyncrasies of MPEG-2 compression, but DVD maintains a
definite edge in picture resolution.)
The MPEG-2 digital video transfer is later synchronized with all the
audio elements (soundtracks and language or commentary tracks) and then
combined on a specialized computer called a "multiplexer," along with all the
potential elements of DVD, including subtitles, menu files, chapter stops,
closed-captioning, parental-control information, regional encoding, and
copy-protection. This digitally combined information is then recorded onto a
tape drive, which is then checked for signal integrity, further inspected for
quality control, and finally used as the data source from which a master DVD
can be made for unlimited duplication.
What does it all mean?
Don't let the techno-babble fool you--find a local consumer outlet
and test-drive DVD for yourself, and remember how readily the public traded in
their vinyl records for music CDs. The same phenomenon appears to be happening
with DVD, although VHS videotapes are far too entrenched in the market to
disappear anytime soon. However, as it becomes clear that DVD will avoid the
niche-market fate of laserdiscs to become the accepted format for home
entertainment, DVD--with its convenience, affordable cost, and superior
performance--speaks for itself.