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"VCD" redirects here. For other uses, see VCD (disambiguation).
This article is about the all-digital \'Video CD\' format. For the earlier (and less successful) analog/digital hybrid, see CD Video.
| Video CD | |
 | |
| Media type | optical disc |
|---|---|
| Encoding | MPEG-1 video + audio |
| Capacity | up to 800 MiB |
| Read mechanism | 780 nm wavelength semiconductor laser |
| Developed by | Sony & Philips |
| Usage | audio and data storage |
Video CD (aka VCD, 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, most modern DVD-Video players, personal computers, and some video game consoles.
The VCD standard was created in 1993Hardware and Software Get an Early Start, Sony, <http://www.sony.net/Fun/SH/1-21/h5.html>. Retrieved on 13 February 2008 Super Video Compact Disc, A Technical Explanation (PDF), Philips System Standards and Licensing, 1998, pp. 2, <http://www.xp-media.com/svcd.pdf>. Retrieved on 13 February 2008 by Sony, Philips, Matsushita, and JVC and is referred to as the White Book standard.
Contents |
Overall picture quality is intended to be comparable to VHS video. Poorly compressed VCD video can sometimes be lower quality than VHS video, but VCD exhibits block artifacts rather than analog noise, and does not deteriorate further with each use, which may be preferable.
352x240 (or SIF) resolution was chosen because it is half the vertical, and half the horizontal resolution of NTSC video. 352x288 is similarly one quarter PAL/SECAM resolution. This approximates the (overall) resolution of an analog VHS tape, which, although it has double the number of (vertical) scan lines, has a much lower horizontal resolution.
VCD video is mostly compatible with the DVD-Video standard, except for any video encoded at 23.976 frames per second. The DVD-Video standard requires video to be encoded at either 25 or 29.97 frames per second.
As with most CD-based formats, VCD audio is incompatible with the DVD-Video standard due to a difference in frequency; DVDs require 48 kHz, whereas VCDs use 44.1 kHz.
Video CDs are authored (or "burned") using the Mode 2/XA format, allowing roughly 800 megabytes of VCD data to be stored on one 80 minute CD (versus 700 megabytes when using Mode 1). This, combined with the net bitrate of VCD video and audio, means that almost exactly 80 minutes of VCD content can be stored on an 80 minute CD, 74 minutes of VCD content on a 74 minute CD, and so on. This was done in part to ensure compatibility with existing CD drive technology, specifically the earliest "1 × speed" CD drives.
The VCD standard also features the option of DVD-quality slide shows of still images, at resolutions of 704x480 (NTSC) or 704x576 (PAL) along with audio.
XVCD (eXtended Video CD) is the name generally given to any format that stores MPEG-1 video on a compact disc in Mode 2/XA, at VCD resolution, but does not strictly follow the VCD standard.
A normal VCD is encoded to MPEG-1 at a constant bit rate (CBR), so all scenes are required to use exactly the same data rate, regardless of complexity. However, video on an XVCD is typically encoded at a variable bit rate (VBR), so complex scenes can use a much higher data rate for a short time, while simpler scenes will use lower data rates.
To further reduce the data rate without significantly reducing quality, the size of the GOP can be increased, a different MPEG-1 quantization matrix can be used, the maximum data rate can be exceeded, and the bit rate of the MP2 audio can be reduced. These changes can be advantageous for those who want to either maximize video quality, or use fewer discs.
KVCD (K Video Compression Dynamics) is a XVCD variant that requires the use of a proprietary quantization matrix, available for non-commercial use. KVCD is notable because the specification recommends a non-standard resolution of 528x480 or 528x576. KVCD discs encoded at this resolution are only playable by computers with CD-ROM drives, and a small number of DVD players.DVD Compatibility Chart, February 25, 2007, <http://www.kvcd.net/portal/articles.php?lng=en&pg=19>. Retrieved on 22 February 2008
DVCD or Double VCD is a method to accommodate longer videos on a CD. A non-standard CD is overburned to include up to 100 minutes of video. However, some CD-ROM drives and players have problems reading these CDs, mostly because the groove spacing is outside specifications and the player\'s laser servo is unable to track it.
While never gaining a foothold in the United StatesMeyer, Scot (April 26, 2001), Versatile Video CD\'s Get a Foothold in U.S., New York Times, <http://query.nytimes.com/gst/fullpage.html?res=9B07E2DD1439F935A15757C0A9679C8B63&sec=&spon=&pagewanted=all>. Retrieved on 12 February 2008 commercial VCDs are common in Europe,Biersdorfer, J. D. (February 8, 2001), Q & A; Another Ingredient In Alphabet Soup: VCD, New York Times, <http://query.nytimes.com/gst/fullpage.html?res=9C06E1D81631F93BA35751C0A9679C8B63&scp=1&sq=VCD&st=nyt>. Retrieved on 12 February 2008 and extremely popular throughout AsiaYoshida, Junko (December, 1999), Video CD: China one, West zero, EE Times, <http://www.eetimes.com/special/special_issues/millennium/milestones/baichuan.html>. Retrieved on 12 February 2008 (except Japan), with 8 million VCD players sold in China in 1997 alone,Leopold, George & Yoshida, Junko (January 13, 1999), Chinese supplier preps low-cost digital TVs for U.S. market, EE Times, <http://www.eetimes.com/story/OEG19990113S0009>. Retrieved on 12 February 2008 and more than half of all Chinese households owning at least one VCD player by 2005.Chinese families double their incomes in 10 years, China Daily, January 12, 2005, <http://www.chinadaily.com.cn/english/doc/2005-01/12/content_408150.htm>. Retrieved on 12 February 2008
This popularity is, in part, because most households did not already own VHS players when VCDs were introduced, 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.Rosenthal, Elisabeth (November 25, 2001), Counterfeiters Turn Magic Into Cash, New York Times, <http://query.nytimes.com/gst/fullpage.html?res=9E06EED7133AF936A15752C1A9679C8B63&sec=&spon=&pagewanted=2>. Retrieved on 12 February 2008 Smith, Craig S. (December 12, 2000), A Tale of Piracy: How the Chinese Stole the Grinch, New York Times, <http://query.nytimes.com/gst/fullpage.html?res=9A01E0DD123FF931A25751C1A9669C8B63&sec=&spon=&pagewanted=all>. Retrieved on 12 February 2008 Faison, Seth (March 28, 1998), China Turns Blind Eye to Pirated Disks, New York Times, <http://query.nytimes.com/gst/fullpage.html?res=9401E1D7143BF93BA15750C0A96E958260&sec=&spon=&pagewanted=all>. Retrieved on 12 February 2008
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. In addition 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 VCDs burned on recordable media.
Many commercial Video CDs of blockbuster Hollywood, Bollywood, Manilawood 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 Pakistan, Hong Kong, India, Mainland China, Thailand, Malaysia, Indonesia and the Philippines. In many Asian countries, major Hollywood studios (and Asian home video distributors) have licensed companies to officially produce and distribute the VCDs, such as MCA Home Video in Pakistan, ERA of Hong Kong or Sunny Video in Malaysia, Vision in Indonesia, Excel Home Videos in India, Berjaya-HVN and InnoForm Media 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 relatively small storage capacity, feature-length films sold on VCD are usually divided into two or three discs and television series may come in a boxed set package with multiple discs. In both cases, most films run at roughly 60 minutes per VCD, before viewers are prompted to change discs. However, there are also VCD players that have built-in CD changers which provide a queue of several discs. Subtitles are found on many Asian VCDs, and unlike DVDs, cannot be removed.
In areas where VCD was formerly very popular, it is now in decline, due to being supplanted by DVD, which offers most of the same advantages, as well as better picture qualityLow DVD Prices to Drive up Sales, People\'s Daily, September 05, 2001, <http://english.peopledaily.com.cn/english/200109/05/eng20010905_79358.html>. Retrieved on 12 February 2008 (higher resolution with less digital compression artifacts) due to its larger storage capacity and 6-speaker surround sound (often in Dolby Digital and/or DTS). However, VCD has simultaneously seen significant new growth in emerging economies like India, Indonesia, South America, Russia and Africa as a low-cost alternative to DVD. Overall, the popularity of VCD is actually increasing.ESS Technology, Inc. 2003 Annual Report (PDF), ESS Technology, 2004, pp. 3, <http://www.esstech.com/IR/Archive_PDF/03bus.pdf>. Retrieved on 17 February 2008
VCD does have a few advantages over DVD-Video:
| Video storage formats | |||||
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| Magnetic tape |
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| Optical disc |
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| Videodisc |
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| Solid state |
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| Other non-volatile storage |
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| TV recording |
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This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia
