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Video CD
(aka VCD, VideoCD, View
CD, Compact Disc digital video) is a standard
digital format for storing video on a Compact Disc. VCDs are playable in
dedicated VCD players, nearly all personal computers, most modern
DVD-Video players, and some video game consoles.
The VCD standard was created in
1993 by Sony, Philips, Matsushita, and JVC and is referred to as the White
Book standard.
Technical
specifications
VCD display resolution is 352 ×
240 pixels (NTSC) or 352 × 288 pixels (PAL), approximately one quarter of
full TV resolution (720 × 480 and 720 × 576 respectively). VCD video is in
MPEG-1 format, and the video bitrate is required to be 1150 kilobits per
second. Audio is encoded as MPEG Layer 2 (MP2) at 224 kbit/s. Overall
picture quality is intended to be comparable to VHS video, though visual
artifacts may be noticeable in some cases. Poorly compressed video in VCD
tends to be of lower quality than VHS video, but exhibiting blocky
artifacts rather than analog noise. 352 horizontal pixels was chosen
because it approximates the resolution of a broadcast video signal,
assuming a 5 MHz bandwidth. Any more than this would be wasted in the RF
modulator, which was the usual means of video input for domestic
television receivers at that time.
Since the overall bit rate of
VCD is approximately equal to the bit rate of an ordinary audio CD, the
length of video that can be stored is similar to that of a CD; but since
VCDs are recorded in Mode 2, which throws away a layer of
error-correction, an 80-minute 700 MB CD can hold nearly 800 MB of
information. The extra space gained allows extra bits to be devoted to the
video image, improving the picture quality. Unfortunately, the missing
error correction also makes the VCD very susceptible to scratches and
fingerprints. Also, variable bitrate encoding (VBR) can be used to make
non-standard VCDs that hold two hours or more and play in ordinary DVD/VCD
players.
Similar
formats
Designed to squeeze the most out of a CD is
the DVCD or Double VCD where a non-standard CD is overburned to include up
to 100 minutes of video. This format is seen only in China and the DVCDs
are playable on many DVD or VCD players though some CD-ROM drives and
players have problems reading these CDs mostly because the groove spacing
is outside specifications and the laser servo is unable to track
it.
A variant of the standard Video
CD encoding known as KVCD is also supported by most (but not all)
standalone DVD players. Not actually a standard as such, KVCD is really
nothing more than a template for the ubiqitous TMPGenc MPEG 1/2 encoder.
As well as VBR encoding, KVCD also uses a reduced audio bitrate and a
'magic' quantization matrix to allow more than two hours of surprisingly
good quality video on one CD. Players known to have trouble with these are
mainly confined to older ones which are often fussy about standards
compliance. The same scenario applies to the SKVCD (or KSVCD) which does
much the same thing as KVCD, but uses MPEG2 and adds some luxuries such as
multiple audio streams and chapters. Most current standalone players now
support (K)SVCD, as the format has been endorsed by Philips, the custodian
of all the CD standards.
Adoption
While never gaining a foothold in the
United States, Europe or Japan, commercial VCDs are very popular
throughout Asia (except Japan) because of the low price of the players,
their tolerance of high humidity (a notable problem for VCRs), and the
lower-cost media. Ease of duplication and the negligible cost of the media
gave rise to widespread unauthorized copying in these
areas.
Available long before DVD-Video,
digital VideoCD might have replaced analog VHS as the dominant home video
format in United States by the mid-1990s. However, because VCDs have
virtually no inherent copy prevention, the format was actively and
sucessfully squashed in the US by the feature film industry. Subsequently,
the US entertainment industry refused to support DVD-Video until it
incorporated multiple layers of copy prevention, holding up DVD-Video's
release to the general public for several years.
The advent of recordable CDs,
inexpensive recorders, and compatible DVD players spurred VCD acceptance
in the US in the late 1990s and early 2000s. However, DVD burners and
DVD-Video recorders were available by that time, and equipment and media
costs for making DVD-Video fell rapidly. DVD-Video, with its longer run
time and much higher quality, quickly overshadowed VCD.
With the advent of CD burners
becoming standard on home PCs, plus the wide availablity of low-cost
MPEG-1 capture devices, VCD was the first digital video recording format
that was widely available to consumers. However, many DVD players made
before 2003-2004 could not read recordable (CD-R) media, and this limited
the compatibility of VCD. Almost every modern stand-alone DVD-Video player
can play VideoCDs burned on recordable media.
Many commercial Video CDs of
blockbuster Hollywood, Bollywood and other Asian movies and television
series are not widely available in the Western countries; however, they
are available in certain ethnic communities and several commercial web
sites (although quality and authenticity may sometimes be questionable).
These VCDs are often produced and sold in Asian countries such as India,
Hong Kong, Mainland China, Thailand, Malaysia and the Philippines. In many
Asian countries, major Hollywood studios have licensed companies to
officially produce and distribute the VCDs, such as MCA in India, ERA of
Hong Kong or Sunny Video in Malaysia, HVN in both Malaysia and Singapore,
as well as VIVA Video, Magnavision, and The Video to C in the Philippines.
Legal Video CDs can often be found in established video stores and major
book outlets in most Asian countries.
Due to relative small storage
capacity, feature-length films sold on VCD are usually divided into two or
three discs and television series may come in a box set package with
multiple discs. In both cases, most films run at roughly 60 minutes per
VCD, before viewers are prompted to change discs. In many Asian movies,
subtitles are not removable on standard VCDs, unlike
DVDs.
VCD is gradually being replaced
by DVD, which offers most of the same advantages to Asian buyers as VCD,
as well as a much better quality picture (higher resolution with less
digital compression artifacts) and sound (often in Dolby Digital and/or
DTS), due to its larger storage capacity.
VCD does however have a few
points in its favor :
- Like VHS and unlike
DVD-Video, the VCD format has no region coding apart from the difference
between NTSC and PAL TV systems, which means that discs can be played on
any compatible machine worldwide. - Some titles available on VCD may
not be available on DVD and/or VHS in the prospective buyer's region. -
They are much cheaper than DVDs. The DVD of a film may cost anywhere from
three to nine times as much as the VCD. On the other hand, VCDs do not
come with the bonus features like that of DVDs, such as choice of
language, (removable) subtitles, chapters, deleted scenes, theatrical and
television previews, interviews, outtakes and production notes. - VCD
is also a very popular format for karaoke in East Asia, where picture
quality concern is not paramount.
These factors may ensure a
steady market for VCDs for many years to come.
Wikipedia information about
Video CD. This article is licensed under the GNU Free Documentation License . It uses material
from the Wikipedia article 'Video CD'
© Copyright disc-formats.guidechart.com 2008, All rights reserved.
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