video this article is about the storage and reproduction medium for their content and production see film for other uses see video disambiguation for the use of video in wikipedia articles see wikipediacreation and usage of media files play media in a video team members share the challenges of mars science laboratorys curiosity final minutes to landing on the surface of mars video is an electronic medium for the recording copying playback broadcasting and display of moving visual media video was first developed for mechanical television systems which were quickly replaced by cathode ray tube crt systems which were later replaced by flat panel displays of several types video systems vary in display resolution aspect ratio refresh rate color capabilities and other qualities analog and digital variants exist and can be carried on a variety of media including radio broadcast magnetic tape optical discs computer files and network streaming history see also history of television video technology was first developed for mechanical television systems which were quickly replaced by cathode ray tube crt television systems but several new technologies for video display devices have since been invented video was originally exclusively a live technology charles ginsburg led an ampex research team developing one of the first practical video tape recorder vtr in 1951 the first video tape recorder captured live images from television cameras by converting the cameras electrical impulses and saving the information onto magnetic video tape video recorders were sold for us 50000 in 1956 and videotapes cost us 300 per onehour reel the use of digital techniques in video created digital video which allows higher quality and eventually much lower cost than earlier analog technology after the invention of the dvd in 1997 and bluray disc in 2006 sales of videotape and recording equipment plummeted advances in computer technology allows even inexpensive personal computers and smartphones to capture store edit and transmit digital video further reducing the cost of video production allowing programmakers and broadcasters to move to tapeless production the advent of digital broadcasting and the subsequent digital television transition is in the process of relegating analog video to the status of a legacy technology in most parts of the world as of 2015 with the increasing use of highresolution video cameras with improved dynamic range and color gamuts and highdynamicrange digital intermediate data formats with improved color depth modern digital video technology is converging with digital film technology characteristics of video streams number of frames per second frame rate the number of still pictures per unit of time of video ranges from six or eight frames per second frames for old mechanical cameras to 120 or more frames per second for new professional cameras pal standards europe asia australia etc and secam france russia parts of africa etc specify 25 frames while ntsc standards usa canada japan etc specify 2997 frames interlaced vs progressive video can be interlaced or progressive in progressive scan systems each refresh period updates all scan lines in each frame in sequence when displaying a natively progressive broadcast or recorded signal the result is optimum spatial resolution of both the stationary and moving parts of the image interlacing was invented as a way to reduce flicker in early mechanical and crt video displays without increasing the number of complete frames per second interlacing retains detail while requiring lower bandwidth compared to progressive scanning in interlaced video the horizontal scan lines of each complete frame are treated as if numbered consecutively and captured as two fields an odd field upper field consisting of the oddnumbered lines and an even field lower field consisting of the evennumbered lines analog display devices reproduce each frame effectively doubling the frame rate as far as perceptible overall flicker is concerned when the image capture device acquires the fields one at a time rather than dividing up a complete frame after it is captured the frame rate for motion is effectively doubled as well resulting in smoother more lifelike reproduction of rapidly moving parts of the image when viewed on an interlaced crt display ntsc pal and secam are interlaced formats abbreviated video resolution specifications often include an i to indicate interlacing for example pal video format is often described as 576i50 where 576 indicates the total number of horizontal scan lines i indicates interlacing and 50 indicates 50 fields halfframes per second when displaying a natively interlaced signal on a progressive scan device overall spatial resolution is degraded by simple line doublingartifacts such as flickering or comb effects in moving parts of the image which appear unless special signal processing eliminates them a procedure known as deinterlacing can optimize the display of an interlaced video signal from an analog dvd or satellite source on a progressive scan device such as an lcd television digital video projector or plasma panel deinterlacing cannot however produce video quality that is equivalent to true progressive scan source material aspect ratio comparison of common cinematography and traditional television green aspect ratios aspect ratio describes the proportional relationship between the width and height of video screens and video picture elements all popular video formats are rectangular and so can be described by a ratio between width and height the ratio width to height for a traditional television screen is 43 or about 1331 high definition televisions use an aspect ratio of 169 or about 1781 the aspect ratio of a full 35mm film frame with soundtrack also known as the academy ratio is 13751 pixels on computer monitors are usually square but pixels used in digital video often have nonsquare aspect ratios such as those used in the pal and ntsc variants of the ccir 601 digital video standard and the corresponding anamorphic widescreen formats the 720 by 480 pixel raster uses thin pixels on a 43 aspect ratio display and fat pixels on a 169 display the popularity of viewing video on mobile phones has led to the growth of vertical video mary meeker a partner at silicon valley venture capital firm kleiner perkins caufield byers highlighted the growth of vertical video viewing in her 2015 internet trends report growing from 5 of video viewing in 2010 to 29 in 2015 vertical video ads like snapchats are watched in their entirety nine times more frequently than landscape video ads color model and depth example of uv color plane y value05 the color model the video color representation and maps encoded color values to visible colors reproduced by the system there are several such representations in common use yiq is used in ntsc television yuv is used in pal television ydbdr is used by secam television and ycbcr is used for digital video the number of distinct colors a pixel can represent depends on color depth expressed in the number of bits per pixel a common way to reduce the amount of data required in digital video is by chroma subsampling eg 444 422 etc because the human eye is less sensitive to details in color than brightness the luminance data for all pixels is maintained while the chrominance data is averaged for a number of pixels in a block and that same value is used for all of them for example this results in a 50 reduction in chrominance data using 2 pixel blocks 422 or 75 using 4 pixel blocks 420 this process does not reduce the number of possible color values that can be displayed but it reduces the number of distinct points at which the color changes video quality video quality can be measured with formal metrics like peak signaltonoise ratio psnr or through subjective video quality assessment using expert observation many subjective video quality methods are described in the itut recommendation bt500 one of the standardized method is the double stimulus impairment scale dsis in dsis each expert views an unimpaired reference video followed by an impaired version of the same video the expert then rates the impaired video using a scale ranging from impairments are imperceptible to impairments are very annoying video compression method digital only video compression uncompressed video delivers maximum quality but with a very high data rate a variety of methods are used to compress video streams with the most effective ones using a group of pictures gop to reduce spatial and temporal redundancy broadly speaking spatial redundancy is reduced by registering differences between parts of a single frame this task is known as intraframe compression and is closely related to image compression likewise temporal redundancy can be reduced by registering differences between frames this task is known as interframe compression including motion compensation and other techniques the most common modern compression standards are mpeg2 used for dvd bluray and satellite television and mpeg4 used for avchd mobile phones 3gp and internet stereoscopic stereoscopic video for 3d film and other applications can be displayed using several different methods two channels a right channel for the right eye and a left channel for the left eye both channels may be viewed simultaneously by using lightpolarizing filters 90 degrees offaxis from each other on two video projectors these separately polarized channels are viewed wearing eyeglasses with matching polarization filters anaglyph 3d where one channel is overlaid with two colorcoded layers this left and right layer technique is occasionally used for network broadcast or recent anaglyph releases of 3d movies on dvd simple redcyan plastic glasses provide the means to view the images discretely to form a stereoscopic view of the content one channel with alternating left and right frames for the corresponding eye using lcd shutter glasses that synchronize to the video to alternately block the image to each eye so the appropriate eye sees the correct frame this method is most common in computer virtual reality applications such as in a cave automatic virtual environment but reduces effective video framerate by a factor of two formats different layers of video transmission and storage each provide their own set of formats to choose from for transmission there is a physical connector and signal protocol video connection standard below a given physical link can carry certain display standards that specify a particular refresh rate display resolution and color space many analog and digital recording formats are in use and digital video clips can also be stored on a computer file system as files which have their own formats in addition to the physical format used by the data storage device or transmission medium the stream of ones and zeros that is sent must be in a particular digital video compression format of which a number are available analog video analog video is a video signal transferred by an analog signal an analog color video signal contains luminance brightness y and chrominance c of an analog television image when combined into one channel it is called composite video as is the case among others with ntsc pal and secam analog video may be carried in separate channels as in two channel svideo yc and multichannel component video formats analog video is used in both consumer and professional television production applications composite videosingle channel rca svideo2channel yc component video3channel rgb scart vga trrc dterminal digital video digital video signal formats with higher quality have been adopted including serial digital interface sdi digital visual interface dvi highdefinition multimedia interface hdmi and displayport interface though analog video interfaces are still used and widely available there exist different adaptors and variants serial digital interface sdi digital visual interface dvi hdmi displayport transport medium video can be transmitted or transported in a variety of ways wireless broadcast as an analog or digital signal coaxial cable in a closed circuit system can be sent as analog interlaced 1 volt peak to peak with a maximum horizontal line resolution up to 480 broadcast or studio cameras use a single or dual coaxial cable system using a progressive scan format known as sdi serial digital interface and hdsdi for high definition video the distances of transmission are somewhat limited depending on the manufacturer the format may be proprietary sdi has a negligible lag and is uncompressed there are initiatives to use the sdi standards in closed circuit surveillance systems for higher definition images over longer distances on coax or twisted pair cable due to the nature of the higher bandwidth needed the distance the signal can be effectively sent is a half to a third of what the older interlaced analog systems supported video connectors cables and signal standards see list of video connectors for information about physical connectors and related signal standards video display standards further information display technology digital television further information broadcast television systems new formats for digital television broadcasts use the mpeg2 video coding format and include atsc united states canada mexico korea digital video broadcasting dvb europe isdb japan isdbtb uses the mpeg4 video coding format brazil argentina digital multimedia broadcasting dmb korea analog television further information broadcast television systems analog television broadcast standards include fcs usa russia obsolete mac europe obsolete muse japan ntsc united states canada japan pal europe asia oceania palm pal variation brazil argentina palplus pal extension europe rs343 military secam france former soviet union central africa an analog video format consists of more information than the visible content of the frame preceding and following the image are lines and pixels containing synchronization information or a time delay this surrounding margin is known as a blanking interval or blanking region the horizontal and vertical front porch and back porch are the building blocks of the blanking interval computer displays see computer display standard for a list of standards used for computer monitors and comparison with those used for television recording formats before video tape phonovision kinescope analog tape formats a vhs video cassette tape in approximate chronological order all formats listed were sold to and used by broadcasters video producers or consumers or were important historically vera 2 quadruplex videotape ampex 1956 vera bbc experimental format ca 1958 1 type a videotape ampex 12 eiaj 1969 umatic 34 sony 12 cartrivision avco vcr vcrlp svr 1 type b videotape robert bosch gmbh 1 type c videotape ampex marconi and sony betamax sony vhs jvc video 2000 philips 2 helical scan videotape ivc 14 cvc funai betacam sony hdvs sony betacam sp sony video8 sony 1986 svhs jvc 1987 vhsc jvc pixelvision fisherprice unihi 12 hd sony hi8 sony mid1990s wvhs jvc 1994 digital tape formats betacam imx sony dvhs jvc dtheater d1 sony d2 sony d3 d5 hd d6 philips digitals d9 jvc digital betacam sony digital8 sony dv including dvcpro hdcam sony hdv prohd jvc micromv minidv optical disc storage formats bluray disc sony china blue highdefinition disc cbhd dvd was super density disc dvd forum professional disc universal media disc umd sony discontinued enhanced versatile disc evd chinese governmentsponsored hd dvd nec and toshiba hdvmd capacitance electronic disc laserdisc mca and philips television electronic disc teldec and telefunken vhd jvc digital encoding formats see also video codec and list of codecs ccir 601 itut h261 itut h263 itut h264mpeg4 avc itut iso h265 mjpeg iso mpeg1 iso mpeg2 itut iso mpeg4 iso oggtheora vp8webm vc1 smpte standards system a system b system g system h system i system m general audio list of video topics video clips video editing videography video format analog television cable television color space color television digital television digital video interlaced progressive scan satellite television telecine television timecode video codec video usage closedcircuit television fulldome video optical feedback video art interactive video video production video projector video synthesizer video sender video teleconference video screen recording screencast bandicam wikimedia commons has media related to video library resources about video resources in your library video as arts at curlie video as media production at curlie programmers guide to video systems indepth technical info on 480i 576i 1080i 720p etc format descriptions for moving images wwwdigitalpreservationgov vteanalog video standards rf connector composite video svideo yc component video ypbpr rgb vtebroadcast video formatstelevisionanalog525 lines system m ntsc ntscj palm 625 lines pal system b system d system g system h system i system k paln palplus secam system b system d system g system k system l secaml audio btsc mts eiaj nicam sap soundinsyncs zweikanalton a2igr hidden signals captioning cgmsa epg gcr pdc teletext vbi veil vit vitc wss xds historical pre1940 mechanical television 180line 405line system a 441line 819line mac muse digitalinterlaced sdtv 480i 576i hdtv 1080i progressive ldtv 1seg 240p 288p edtv 480p 576p hdtv 720p 1080p uhdtv 2160p 4320p mpeg2 standards atsc dvb isdb dtmb dvb 3dtv mpeg4 avc standards atsc a72 dmb dtmb dvb sbtvd 1seg hevc standards atsc 30 audio ac3 51 ac4 dts mpeg1 audio layer ii mpeg multichannel pcm lpcm aac heaac mpegh 3d audio hidden signals afd broadcast flag captioning cpcm epg teletext technical issues 149 compromise broadcastsafe digital cinema dci display motion blur moving image formats mpeg transport stream reverse standards conversion standards conversion television transmitter video on demand video processing widescreen signaling templates analogue tv topics vtevideo storage formatsvideotapeanalog quadruplex 1956 vera 1958 ampex 2 inch helical vtr 1961 sony 2 inch helical vtr 1961 type a 1965 cv2000 1965 akai 1967 umatic 1969 eiaj1 1969 cartrivision 1972 philips vcr 1972 vcord 1974 vx 1974 betamax 1975 ivc 1975 type b 1976 type c 1976 vhs 1976 vk 1977 svr 1979 video 2000 1980 cvc 1980 vhsc 1982 m 1982 betacam 1982 video8 1985 mii 1986 svhs 1987 svhsc 1987 hi8 1989 ruvi 1998 digital d1 1986 d2 1988 d3 1991 dct 1992 digital betacam 1993 d5 1994 digitals d9 1995 betacam sx 1996 digital8 1999 micromv 2001 high definition sony hdvs 1984 unihi 1984 wvhs 1994 hdcam 1997 dvhs 1998 d6 hdtv vtr 2000 hdv 2003 hdcam sr 2003 videodiscanalog phonovision 1927 ampexhs 1967 ted 1975 laserdisc 1978 ced 1981 vhd 1983 laserfilm 1984 cd video 1987 vsd 1990 digital vcd 1993 moviecd 1996 dvd 1996 minidvd c 1996 dvdvideo 1997 cvd 1998 svcd 1998 evd 2003 pvd personal video disc 2003 hvd highdefinition versatile disc 2004 umd 2004 fvd 2005 high definition muse hivision ld 1994 vmd 2006 hd dvd 2006 brd bdbluray disc 2006 minibd c 2006 hvd holographic versatile disc 2007 cbhd china blue highdefinition disc 2008 uhd brd ultra hd bluray disc 2016 virtualmedia agnostic dv 1995 dvcpro 1995 dvcam 1996 dvcpro50 1997 dvcpro hd 2000 tapeless camcutter editcam 1995 xdcam 2003 mod 2005 avchd 2006 avcintra 2006 tod 2007 iframe 2009 xavc 2012 solid state p2 2004 sxs 2007 microp2 2012 video recorded to film kinescope 1947 electronicam kinescope 1950s electronic video recording 1967 vtevideo digital distribution platforms digital library streaming media video on demand free 56com 7plus 9now abc iview aparat acfun afreecatv all 4 arte boutique bbc iplayer bilibili blinkbox breakcom brightcove buzznet canalplay chicken pork adobo dailymotion daum dittotv facebook watch the film detective filmon flickr fotki france tv pluzz funimation funny or die funshion gogcom gyao hitchhike tv hoopla hotstar hunter tv iqiyi itv hub iwant le lightbox liveleak mango tv medicitv metacafe mixer my5 mytf1 vod myvideo naver neulion the newsmarket niconico noggin oneworldtv ora tv overdrive inc pandora tv picturebox films pluto tv popcornflix pptv putlocker rt player rumble rutube schooltube showroom sky go smashcasttv sohu sony crackle sony liv spirit show network spuul starlight networks steam streamworks international stv player svt play talktalk tv tank top tv tapp tv teachertube teaching channel telly inc theplatform toon goggles trilulilu tubi tudou tv uol tvigle tvnz ondemand tvplayer tvyo twitchtv uktv play ultraviolet vbox7 veoh vevo viddsee viewster viki vimeo virgin media player viu voddler vudu vqqcom vyrt wistia wuaki xfinity streampix xunlei kankan yahoo view youku youtube yupptv zattoo sports fox sports go nbl tv watchespn pornographic pornerbros pornhub pornmd pornotube redtube xhamster xtube xvideos youporn paid acorn tv animelab britbox cbs all access crave crunchyroll curiositystream dc universe disney fandangonow fandor the film detective fullscreen hbo now hillsong channel now hooq hulu icflix iflix kocowa mubi netflix now tv playstation video playster prime video rooster teeth first shahid showmax showtime shudder sky on demand stan starz vidangel watchtoku youtube premium live television directv now foxtel now localbtv playstation vue sling tv tvplayer youtube tv sports br live dazn eleven sports espn nbc sports gold ufc fight pass rental purchase amazon video google play movies tv itunes store movies anywhere nintendo eshop playstation store vudu microsoft store microsoft movies tv wrestling all japan pro wrestling tv big japan pro wrestling core club wwn chikaratopia czw studios ddt universe dragon gate network global wrestling network honor club new japan prowrestling world stardom world wwe network wwnlive discontinued azubu bbc store blip blogtv cinemanow daisuki dramafever fearnet filmstruck flixster google video hitboxtv imeem imesh intel appup joost justintv kazaa lovefilm megavideo muzutv nintendo channel nintendo video nokia store openfilm plus7 presto quickflix redbox revver seeso shomi sony entertainment network stage6 super deluxe touchvision triton trooptube twango total access impact wrestling vdio vessel viddler vidme vine vongo warner archive instant weshow windows media center wwe classics on demand yahoo screen vtedata compression methodslosslessentropy type unary arithmetic asymmetric numeral systems golomb huffman adaptive canonical modified range shannon shannonfano shannonfanoelias tunstall universal expgolomb fibonacci gamma levenshtein dictionary type byte pair encoding deflate snappy lempelziv lz77 lz78 lz1 lz2 lzfse lzjb lzma lzo lzrw lzs lzss lzw lzwl lzx lz4 brotli zstandard other types bwt ctw delta dmc mtf paq ppm rle audioconcepts bit rate average abr constant cbr variable vbr companding convolution dynamic range latency nyquistshannon theorem sampling sound quality speech coding subband coding codec parts alaw law acelp adpcm celp dpcm fourier transform lpc lar lsp mdct psychoacoustic model wlpc imageconcepts chroma subsampling coding tree unit color space compression artifact image resolution macroblock pixel psnr quantization standard test image methods chain code dct ezw fractal klt lp rle spiht wavelet videoconcepts bit rate average abr constant cbr variable vbr display resolution frame frame rate frame types interlace video characteristics video quality codec parts lapped transform dct deblocking filter motion compensation theory entropy kolmogorov complexity lossy quantization ratedistortion redundancy timeline of information theory compression formats compression software codecs vteindependent productionreading alternative comics alternative manga fanzine webcomic business webtoon minicomic coops djinshi conventions printers shops self publishing small press amateur press association audio independent music record label netlabel opensource label radio station pirate radio cassette culture djin music lofi music tracker mod music podsafe musical instruments circuit bending experimental musical instrument videoamateur home movies amateur film amateur pornography fan film machinima professional independent animation cinema of transgression independent film exploitation film guerrilla filmmaking b movie golden age 50s 60s70s 80spresent z movie midnight movie lowbudget film no budget film no wave cinema double feature software cowboy coding demoscene free software opensource software software cracking unofficial patch warez scene video games indie gamesdevelopmentdevelopers homebrew fangame djin soft mod opensource video game rom hack fooddrinks independent soft drink homebrewing microbrewery other indie art amateur photography mail art nave art outsider art visionary environment indie rpg independent circuit wrestling independent tv station general indie design do it yourself diy ethic djin make magazine maker faire social peertopeer processes 