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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'








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