|
== Техническо описание ==
=== Видео ===
* Разделителна способност:
** [[NTSC]]: 352x240
** [[PAL]]/[[SECAM]]: 352x288
=== Аудио ===
* стерео (два канала), с честота 44.1 Khz
Предимството на VCD е в липсата на аналогов шум и това, че носителят не остарява и не губи качество след многократно възпроизвеждане.
== Източници ==
<!-- == Technical specifications ==
===Container===
In a VCD, the audio and video streams are [[Multiplexing#Video_processing|multiplexed]] in an [[MPEG-PS]] container.
===Video===
* Codec: [[MPEG-1]]
* Resolution:
** [[NTSC]]: 352x240
** [[PAL]]/[[SECAM]]: 352x288
* [[Aspect Ratio]]:
** [[NTSC]]: 107:80 (0.3% difference from 4:3)
** [[PAL]]/[[SECAM]]: 4:3
* Framerate:
** [[NTSC]]: 29.97 ''or'' 23.976 frames per second
** [[PAL]]/[[SECAM]]: 25 frames per second
* Bitrate: 1,150 [[kilobit]]s per second
** Rate Control: [[constant bitrate]]
Overall picture quality is intended to be comparable to [[VHS]] video.
Poorly [[Video compression|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.
352x240 (or [[Source Input Format|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, which must use [[3:2 pulldown]].
===Audio===
* Codec: [[MPEG-1#Part_3:_Audio|MPEG-1 Audio Layer II]]
* Frequency: 44,100 [[hertz]] (44.1 kHz)
* Output: Dual channel or [[stereo]]
* Bitrate: 224 [[kilobit]]s per second
** Rate Control: [[Constant bitrate]]
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.
===Other information===
{{trivia|date=February 2009}}
Video CDs are [[Optical disc authoring|authored]] using the [[CD-ROM XA|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 still images/slide shows with audio, at resolutions of 704x480 (NTSC) or 704x576 (PAL/SECAM). Version 2.0 also adds the [[playback control]] (PBC), featuring a simple menu like DVD-video.
== Similar formats ==
=== CD-i Digital Video ===
Shortly before the advent of White Book VCD, Philips started releasing movies in the [[Green Book (CD-interactive standard)|Green Book]] [[CD-i]] format. While these used a similar format (MPEG-1), due to minor differences between the standards these discs are not compatible with VCD players. Philips' CD-i players with the Full Motion Video MPEG-1 decoder cartridge would play both formats. Only a few CD-i DV titles were released before the company switched to proper VCD format for publishing movies.
=== XVCD ===
'''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 [[Group of pictures|GOP]] can be increased, a different MPEG-1 [[quantization (image processing)#Quantization_matrices|quantization matrix]] can be used, the maximum data rate can be exceeded, and the bit rate of the MP2 audio can be reduced (or even the use of MP3 audio instead of MP2 audio). These changes can be advantageous for those who want to either maximize video quality, or use fewer discs.
=== KVCD ===
'''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.<ref>{{Citation | title = DVD Compatibility Chart | date= February 25, 2007 | url = http://www.kvcd.net/portal/articles.php?lng=en&pg=19 | accessdate = 2008-02-22 }}</ref> KVCDs of commercial films are commonly distributed as [[optical disc image|disc image]]s on [[peer-to-peer]] networks.{{Fact|date=April 2008}}
=== DVCD ===
'''DVCD''' or Double VCD is a method to accommodate longer videos on a CD. A non-standard CD is [[overburn]]ed 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.
== Adoption ==
===In North America===
The advent of [[CD-R|recordable CDs]], inexpensive recorders, and compatible DVD players spurred VCD acceptance in the US in the late 1990s and early 2000s.<ref name=nytfoothold>{{Citation | first = Scot | last = Meyer | title = Versatile Video CD's Get a Foothold in U.S. | date=April 26, 2001 | publisher = [[New York Times]] | url = http://query.nytimes.com/gst/fullpage.html?res=9B07E2DD1439F935A15757C0A9679C8B63&sec=&spon=&pagewanted=all | accessdate = 2008-02-12 }}</ref> 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 areas that could afford it. In addition many early DVD players could not read recordable (CD-R) media,<ref>{{Citation | first = Hugh | last = Bennett | title = DVD-ROM and CD-R: the compatibility question answered - includes related article on reading mixed media | date= March, 1998 | publisher = [[Emedia Professional]] | url = http://findarticles.com/p/articles/mi_m0FXG/is_n3_v11/ai_20324077 | accessdate = 2008-04-26 }}</ref> and this limited the compatibility of home-made VCDs. Almost every modern stand-alone DVD-Video player can play VCDs burned on recordable media.
===In Asia===
The VCD format is very popular throughout [[Asia]]<ref>{{Citation | first = Junko | last = Yoshida | title = Video CD: China one, West zero | date=December, 1999 | publisher = [[EE Times]] | url = http://www.eetimes.com/special/special_issues/millennium/milestones/baichuan.html | accessdate = 2008-02-12 }}</ref>
(except Japan), with 8 million VCD players sold in China in 1997 alone,<ref>{{Citation | first = George | last = Leopold | first2 = Junko | last2 =Yoshida | title = Chinese supplier preps low-cost digital TVs for U.S. market | date=January 13, 1999 | publisher = [[EE Times]] | url = http://www.eetimes.com/story/OEG19990113S0009 | accessdate = 2008-02-12 }}</ref>
and more than half of all Chinese households owning at least one VCD player by 2005.<ref>{{Citation | title = Chinese families double their incomes in 10 years | date=January 12, 2005 | publisher = [[China Daily]] | url = http://www.chinadaily.com.cn/english/doc/2005-01/12/content_408150.htm | accessdate = 2008-02-12 }}</ref>
VCDs are often produced and sold in Asian countries such as [[China]], [[Taiwan]], [[Hong Kong]], [[Singapore]], [[Malaysia]], [[Thailand]], [[Burma]], [[Indonesia]], [[Philippines]], [[India]] and [[Pakistan]]. In many Asian countries, major Hollywood studios (and Asian home video distributors) have licensed companies to officially produce and distribute the VCDs, such as [[Music Corporation of America|MCA Home Video]] in [[Pakistan]], ERA of Hong Kong or Sunny Video in Malaysia, Vision in Indonesia, CVD International and Pacific Marketing and Entertainment Group in Thailand, 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.
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.<ref name=nytfoothold/> Western sources have cited counterfeiting as a principal concern of VCD users.<ref>{{Citation | first = Elisabeth | last = Rosenthal | title = Counterfeiters Turn Magic Into Cash | date=November 25, 2001 | publisher = [[New York Times]] | url = http://query.nytimes.com/gst/fullpage.html?res=9E06EED7133AF936A15752C1A9679C8B63&sec=&spon=&pagewanted=2 | accessdate = 2008-02-12 }}</ref><ref name=nytgrinch>{{Citation | first = Craig S. | last = Smith | title = A Tale of Piracy: How the Chinese Stole the Grinch | date=December 12, 2000 | publisher = [[New York Times]] | url = http://query.nytimes.com/gst/fullpage.html?res=9A01E0DD123FF931A25751C1A9669C8B63&sec=&spon=&pagewanted=all | accessdate = 2008-02-12 }}</ref><ref>{{Citation | first = Seth | last = Faison | title = China Turns Blind Eye to Pirated Disks | date=March 28, 1998 | publisher = [[New York Times]] | url = http://query.nytimes.com/gst/fullpage.html?res=9401E1D7143BF93BA15750C0A96E958260&sec=&spon=&pagewanted=all | accessdate = 2008-02-12 }}</ref>
In Asia, the use of VCDs as carriers for [[karaoke]] music is very common.
===In India===
VCD is popular among the [[Bollywood]] industry, many Indian movies being sold on VCD which allowed even poor families to afford them. However, because of Bollywood's rapidly increasing popularity, there are high demands for optional subtitles in other languages to be included with the movie along with "bonus" material like its competitor, [[Hollywood]], this is causing Bollywood to depend more strictly on DVD.
===In Burma===
In Burma, VCDs are the medium of an underground video network that largely stays beneath the sights of [[Military of Burma|the military regime]], although VCD trends are reported on by expatriate newspapers. Popular videos include Buddhist monks speaking out against the regime<ref>http://www.irrawaddy.org/article.php?art_id=9343</ref> and comedy skits ruthlessly mocking military leaders.<ref>http://www.irrawaddy.org/article.php?art_id=9716</ref> It is reported that even soldiers watch the VCDs in their barracks.<reF>http://www.irrawaddy.org/article.php?art_id=14093</ref>
===Worldwide trends===
VCD's growth has slowed in areas that can afford [[DVD-Video]], which offers most of the same advantages, as well as better picture quality<ref>{{Citation | title = Low DVD Prices to Drive up Sales | date=September 05, 2001 | publisher = [[People's Daily]] | url = http://english.peopledaily.com.cn/english/200109/05/eng20010905_79358.html | accessdate = 2008-02-12 }}</ref>
(higher resolution with fewer digital compression artifacts) due to its larger storage capacity. However, VCD has simultaneously seen significant new growth in emerging economies like [[India]], [[Indonesia]], [[South America]] and [[Africa]] as a low-cost alternative to DVD. As of 2004, the worldwide popularity of VCD was increasing.<ref>{{Citation | title = ESS Technology, Inc. 2003 Annual Report (PDF) | year = 2004 | publisher = [[ESS Technology]] | url = http://www.esstech.com/IR/Archive_PDF/03bus.pdf |format=PDF| pages = 3 | accessdate = 2008-02-17 }}</ref><ref>{{Citation | title = ESS product to vie with VCD players | date=August 10, 2004 | publisher = [[People's Daily]] | url = http://english.peopledaily.com.cn/200408/10/eng20040810_152444.html | accessdate = 2008-04-01 }}</ref>
===Compared with DVD===
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 [[Box set|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.
VCD does have a few advantages over DVD-Video:
* The VCD format has no [[region coding]], so discs can be played on any compatible machine worldwide. Many VCD players can compensate for the differing frame rate and pixel count between NTSC and PAL/SECAM TV systems.
* Some titles available on VCD may not be available on DVD and/or VHS in the prospective buyer's region.<ref>[http://www.vcdgallery.com/help.htm VCD Help & FAQ - what is a vcd] from vcdgallery.com Retrieved on 24 April 2008</ref>
==Software support==
Video CDs are not popular in the US and Europe, so its support is limited among mainstream software. [[Windows Media Player]] prior to version 9 and [[Quicktime player]] do not support playing VCD directly, though they can play the DAT files (stored under \MPEGAV for video and audio data) reliably. [[Windows Vista]] added native support of VCD like DVD-Video and can launch preferred application upon inserting.
== See also ==
* [[Laserdisc]] - The larger analog predecessor to Video CD
* [[CD Video]] - A 1980s format combining the [[laserdisc]] and the [[CD]]
* [[Super Video CD]] (SVCD) - A direct successor to Video CD
* [[DVD]] - A higher capacity and much more successful follow-up to Video CD
* [[cDVD]] - (AKA Mini-DVD), DVD video on a CD
* [[DcVD]] - A non-standard MPEG-1 format for the Sega Dreamcast video game console
* [[MovieCD]] - A proprietary 1990s format using the ''MotionPixels'' codec
* [[Blu-ray]] - A new type of disc that allows much more data
== References ==
{{reflist|2}}
== Външни връзки ==
* [http://www.ip.philips.com/licensing/licensingprogramshistory/history_videocdplayer_joint.html Patent History Video CD Player] - published by [[Philips]] 2003
* [http://www.ip.philips.com/licensing/licensingprogramshistory/history_videocddisc_joint.html Patent History Video CD Disc] - published by [[Philips]] 2003
* [http://www.videohelp.com/vcd What is VCD?] - from VideoHelp.com
* [http://www.vcdhelp.com/ VCD Help]
* [http://www.vcdgallery.com/help.htm How Do You Play VCDs?]
* [http://www.mireth.com/wt/v530.html How to Play VCD on Mac/Windows computer, DVD Player] - from Mireth Technology
* [http://www.Doom9.org/index.html?/mpg/vcdsvcd_faq.htm VCD / SVCD / miniDVD FAQ] - from Doom9.org
{{Homevid}}
-->
==Източници==
<references/>
| 