Video is an

electronic Electronic may refer to: *Electronics, the science of how to control electric energy in semiconductor * ''Electronics'' (magazine), a defunct American trade journal *Electronic storage, the storage of data using an electronic device *Electronic co ...

medium for the recording, copying, playback,

broadcasting Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum ( radio waves), in a one-to-many model. Broadcasting beg ...

, and display of moving

visual The visual system comprises the sensory organ (the eye) and parts of the central nervous system (the retina containing photoreceptor cells, the optic nerve, the optic tract and the visual cortex) which gives organisms the sense of sight (th ...

media Media may refer to: Communication * Media (communication), tools used to deliver information or data ** Advertising media, various media, content, buying and placement for advertising ** Broadcast media, communications delivered over mass e ...

. Video was first developed for

mechanical television Mechanical television or mechanical scan television is a television system that relies on a mechanical scanning device, such as a rotating disk with holes in it or a rotating mirror drum, to scan the scene and generate the video signal, and a si ...

systems, which were quickly replaced by cathode-ray tube (CRT) systems which, in turn, were replaced by

flat panel display A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment. Flat-panel displays are thin, lightweight, provide better l ...

s of several types. Video systems vary in

display resolution The display resolution or display modes of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution ...

, aspect ratio,

refresh rate The refresh rate (or "vertical refresh rate", "vertical scan rate", terminology originating with the cathode ray tubes) is the number of times per second that a raster-based display device displays a new image. This is independent from frame rate ...

, color capabilities and other qualities. Analog and digital variants exist and can be carried on a variety of media, including

radio broadcast Radio broadcasting is transmission of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radio sta ...

, magnetic tape,

optical disc In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data (bits) in the form of pits and lands on a special material, often aluminum, on one of its flat surfaces. ...

computer files A computer file is a computer resource for recording data in a computer storage device, primarily identified by its file name. Just as words can be written to paper, so can data be written to a computer file. Files can be shared with and transf ...

, and network streaming.

History

Analog video

Video technology was first developed for

systems, which were quickly replaced by cathode-ray tube (CRT)

television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...

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 Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name AMPEX is a portmanteau, created by its founder, which stands for Alexander M. Poniatoff Excellence.AbramsoThe History ...

research team developing one of the first practical

video tape recorder A video tape recorder (VTR) is a tape recorder designed to record and playback video and audio material from magnetic tape. The early VTRs were open-reel devices that record on individual reels of 2-inch-wide (5.08 cm) tape. They were u ...

s (VTR). In 1951, the first VTR captured live images from

television camera A professional video camera (often called a television camera even though its use has spread beyond television) is a high-end device for creating electronic moving images (as opposed to a movie camera, that earlier recorded the images on film). ...

s by writing the camera's electrical signal onto magnetic

videotape Videotape is magnetic tape used for storing video and usually sound in addition. Information stored can be in the form of either an analog or digital signal. Videotape is used in both video tape recorders (VTRs) and, more commonly, videocasse ...

. Video recorders were sold for US$50,000 in 1956, and videotapes cost US$300 per one-hour reel. However, prices gradually dropped over the years; in 1971, Sony began selling

videocassette recorder A videocassette recorder (VCR) or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other source on a removable, magnetic tape videocassette, and can play back the reco ...

(VCR) decks and tapes into the consumer market.

Digital video

Digital video is capable of higher quality and, eventually, much lower cost than earlier analog technology. After the invention of the

DVD The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind ...

in 1997, and later the Blu-ray Disc in 2006, sales of videotape and recording equipment plummeted. Advances in computer technology allows even inexpensive

personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...

s and

smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...

s to capture, store, edit and transmit digital video, further reducing the cost of

video production Video production is the process of producing video content for video. It is the equivalent of filmmaking, but with video recorded either as analog signals on videotape, digitally in video tape or as computer files stored on optical discs, hard dri ...

, allowing program-makers and broadcasters to move to tapeless production. The advent of

digital broadcasting Digital broadcasting is the practice of using digital signals rather than analogue signals for broadcasting over radio frequency bands. Digital television broadcasting (especially satellite television) is widespread. Digital audio broadcasting i ...

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. The development of high-resolution video cameras with improved

dynamic range Dynamic range (abbreviated DR, DNR, or DYR) is the ratio between the largest and smallest values that a certain quantity can assume. It is often used in the context of Signal (electrical engineering), signals, like sound and light. It is measured ...

and

color gamut In color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain ''complete subset'' of colors. The most common usage refers to the subset of colors which can be accurately represented in a given ci ...

s, along with the introduction of high-dynamic-range

digital intermediate Digital intermediate (typically abbreviated DI) is a motion picture finishing process which classically involves digitizing a motion picture and manipulating the color and other image characteristics. Definition and overview A digital intermediat ...

data formats with improved color depth, has caused digital video technology to converge with film technology. the usage of

digital cameras A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile devices ...

in Hollywood has surpassed use of film cameras.

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 (''frame/s'') for old mechanical cameras to 120 or more frames per second for new professional cameras.

PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

standards (Europe, Asia, Australia, etc.) and

SECAM SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''color sequential with memory''), is an analog color television system that was used in France, some parts of Europe and Africa, and Russia. It was one of th ...

(France, Russia, parts of Africa etc.) specify 25 frame/s, while

NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...

standards (USA, Canada, Japan, etc.) specify 29.97 frame/s. Film is shot at the slower frame rate of 24 frames per second, which slightly complicates the process of transferring a cinematic motion picture to video. The minimum frame rate to achieve a comfortable illusion of a

moving image A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...

is about sixteen frames per second.

Interlaced vs progressive

Video can be

interlaced Interlaced video (also known as interlaced scan) is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. This ...

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 A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction *Framing (con ...

. Interlacing retains detail while requiring lower

bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

compared to progressive scanning. In interlaced video, the horizontal

scan line A scan line (also scanline) is one line, or row, in a raster scanning pattern, such as a line of video on a cathode ray tube (CRT) display of a television set or computer monitor. On CRT screens the horizontal scan lines are visually discernible ...

s of each complete frame are treated as if numbered consecutively, and captured as two ''fields'': an ''odd field'' (upper field) consisting of the odd-numbered lines and an ''even field'' (lower field) consisting of the even-numbered 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 (half-frames) per second. When displaying a natively interlaced signal on a progressive scan device, overall spatial resolution is degraded by simple

line doubling A line doubler is a device or algorithm used to deinterlace video signals prior to display on a progressive scan display. The main function of a deinterlacer is to take an interlaced video frame which consists of 60 two-field interlaced fields ...

—artifacts 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 Deinterlacing is the process of converting interlaced video into a non-interlaced or Progressive scan, progressive form. Interlaced video signals are commonly found in analog television, digital television (HDTV) when in the 1080i format, some D ...

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 Liquid-crystal-display televisions (LCD TVs) are television sets that use liquid-crystal displays to produce images. They are, by far, the most widely produced and sold television display type. LCD TVs are thin and light, but have some disadvantag ...

, digital

video projector A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. Video projectors use a very bright ultra-high-performance lamp (a special mercury arc lamp), X ...

or plasma panel. Deinterlacing cannot, however, produce video quality that is equivalent to true progressive scan source material.

Aspect ratio

Aspect ratio describes the proportional relationship between the width and height of video screens and video picture elements. All popular video formats are

rectangular In Euclidean plane geometry, a rectangle is a quadrilateral with four right angles. It can also be defined as: an equiangular quadrilateral, since equiangular means that all of its angles are equal (360°/4 = 90°); or a parallelogram containin ...

, and so can be described by a ratio between width and height. The ratio width to height for a traditional television screen is 4:3, or about 1.33:1. High definition televisions use an aspect ratio of 16:9, or about 1.78:1. The aspect ratio of a full 35 mm film frame with soundtrack (also known as the Academy ratio) is 1.375:1.

Pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the ...

s on computer monitors are usually square, but pixels used in digital video often have non-square aspect ratios, such as those used in the PAL and NTSC variants of the

CCIR 601 ITU-R Recommendation BT.601, more commonly known by the abbreviations Rec. 601 or BT.601 (or its former name CCIR 601) is a standard originally issued in 1982 by the Comité consultatif international pour la radio, CCIR (an organization, ...

digital video standard, and the corresponding anamorphic widescreen formats. The 720 by 480 pixel raster uses thin pixels on a 4:3 aspect ratio display and fat pixels on a 16:9 display. The popularity of viewing video on mobile phones has led to the growth of

vertical video A vertical video is a video created either by a camera or computer that is intended for viewing in portrait mode, producing an image that is taller than it is wide. It thus sits in opposition to the multiple horizontal formats normalised by ci ...

. Mary Meeker, a partner at Silicon Valley venture capital firm

Kleiner Perkins Caufield & Byers Kleiner Perkins, formerly Kleiner Perkins Caufield & Byers (KPCB), is an American venture capital firm which specializes in investing in incubation, early stage and growth companies. Since its founding in 1972, the firm has backed entrepreneur ...

, 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 Snapchat’s are watched in their entirety nine times more frequently than landscape video ads.

Color model and depth

The

color model A color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components. When this model is associated with a precise description of how the compon ...

the video color representation and maps encoded color values to visible colors reproduced by the system. There are several such representations in common use: typically YIQ is used in NTSC television,

YUV YUV is a color model typically used as part of a color image pipeline. It encodes a color image or video taking human perception into account, allowing reduced bandwidth for chrominance components, compared to a "direct" RGB-representation. H ...

is used in PAL television,

YDbDr YDbDr, sometimes written YDBDR, is the colour space used in the SECAM analog terrestrial colour television broadcasting standard (adopted in France and some countries of the former Eastern Bloc) and PAL-N (adopted in Argentina, Paraguay and Urugu ...

is used by SECAM television and

YCbCr YCbCr, Y′CbCr, or Y Pb/Cb Pr/Cr, also written as YCBCR or Y′CBCR, is a family of color spaces used as a part of the color image pipeline in video and digital photography systems. Y′ is the luma component and CB and CR are the blue-diff ...

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 Chroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for color differences than for luminance. It is u ...

(e.g., 4:4:4, 4:2:2, 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 (4:2:2) or 75% using 4-pixel blocks (4:2:0). 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 signal-to-noise ratio Peak signal-to-noise ratio (PSNR) is an engineering term for the ratio between the maximum possible power of a signal and the power of corrupting noise that affects the fidelity of its representation. Because many signals have a very wide dynamic ...

(PSNR) or through

subjective video quality Subjective video quality is video quality as experienced by humans. It is concerned with how video is perceived by a viewer (also called "observer" or "subject") and designates their opinion on a particular video sequence. It is related to the fiel ...

assessment using expert observation. Many subjective video quality methods are described in the

ITU-T The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Comm ...

recommendation BT.500. One of the standardized methods 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)

Uncompressed video Uncompressed video is digital video that either has never been compressed or was generated by decompressing previously compressed digital video. It is commonly used by video cameras, video monitors, video recording devices (including general-purp ...

delivers maximum quality, but at 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 In video coding, a group of pictures, or GOP structure, specifies the order in which intra- and inter-frames are arranged. The GOP is a collection of successive pictures within a coded video stream. Each coded video stream consists of successive ...

(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 Intra-frame coding is a data compression technique used within a video frame, enabling smaller file sizes and lower bitrates, with little or no loss in quality. Since neighboring pixels within an image are often very similar, rather than storing ...

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 Motion compensation in computing, is an algorithmic technique used to predict a frame in a video, given the previous and/or future frames by accounting for motion of the camera and/or objects in the video. It is employed in the encoding of video d ...

and other techniques. The most common modern compression standards are MPEG-2, used for

Blu-ray The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of st ...

and

satellite television Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna comm ...

, and MPEG-4, used for

AVCHD AVCHD (Advanced Video Coding High Definition) is a file-based format for the digital recording and playback of high-definition video. It is H.264 and Dolby AC-3 packaged into the MPEG transport stream, with a set of constraints designed around t ...

, 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 light-polarizing filters 90 degrees off-axis from each other on two video projectors. These separately polarized channels are viewed wearing eyeglasses with matching polarization filters. *

Anaglyph 3D Anaglyph 3D is the stereoscopic 3D effect achieved by means of encoding each eye's image using filters of different (usually chromatically opposite) colors, typically red and cyan. Anaglyph 3D images contain two differently filtered colored ...

where one channel is overlaid with two color-coded layers. This left and right layer technique is occasionally used for network broadcast or recent anaglyph releases of 3D movies on DVD. Simple red/cyan 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 An active shutter 3D system (a.k.a. alternate frame sequencing, alternate image, AI, alternating field, field sequential or eclipse method) is a technique of displaying stereoscopic 3D images. It works by only presenting the image intended for t ...

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 Virtual reality (VR) is a simulated experience that employs pose tracking and 3D near-eye displays to give the user an immersive feel of a virtual world. Applications of virtual reality include entertainment (particularly video games), e ...

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 (see

List of video connectors This is a list of physical RF and video connectors and related video signal standards. By signal standard Physical connectors D-subminiature family DVI-related DIN/Mini-DIN Others See also *Computer display standard Computer dis ...

). A given physical link can carry certain display standards that specify a particular refresh rate,

, and

color space A color space is a specific organization of colors. In combination with color profiling supported by various physical devices, it supports reproducible representations of colorwhether such representation entails an analog or a digital represen ...

. Many analog and digital

recording format A recording format is a format for encoding data for storage on a storage medium. The format can be container information such as sectors on a disk, or user/audience information (content) such as analog stereo audio. Multiple levels of encodi ...

s 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 coding format A video coding format (or sometimes video compression format) is a content representation format for storage or transmission of digital video content (such as in a data file or bitstream). It typically uses a standardized video compression algori ...

, of which a number are available.

Analog video

Analog video is a video signal represented by one or more analog signals. Analog color video signals include luminance, brightness (Y) and

chrominance Chrominance (''chroma'' or ''C'' for short) is the signal used in video systems to convey the color information of the picture (see YUV color model), separately from the accompanying luma signal (or Y' for short). Chrominance is usually represente ...

(C). When combined into one channel, as is the case, among others with

and

it is called composite video. Analog video may be carried in separate channels, as in two channel

S-Video S-Video (also known as separate video, Y/C, and erroneously Super-Video ) is an analog video signal format that carries standard-definition video, typically at 525 lines or 625 lines. It encodes video luma and chrominance on two separate chan ...

(YC) and multi-channel

component video Component video is an analog video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video (CAV) information that is transmitted or stored as three separate signals. Compo ...

formats. Analog video is used in both consumer and professional

television production A television show – or simply TV show – is any content produced for viewing on a television set which can be broadcast via over-the-air, satellite, or cable, excluding breaking news, advertisements, or trailers that are typically placed be ...

applications. Composite-video-cable.jpg, Composite video
(single channel RCA) Close-up_of_S-video_female_connector.jpg,

(2-channel YC) Component-cables.jpg,

Component video Component video is an analog video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video (CAV) information that is transmitted or stored as three separate signals. Compo ...

(3-channel

YPbPr YPbPr or Y'PbPr, also written as , is a color space used in video electronics, in particular in reference to component video cables. YPBPR is gamma corrected YCBCR color space (it is not analog YUV that was used for analog TV, though component ...

) SCART_20050724_002.jpg,

SCART SCART (also known as or , especially in France, 21-pin EuroSCART in marketing by Sharp in Asia, Euroconector in Spain, EuroAV or EXT, or EIA Multiport in the United States, as an EIA interface) is a French-originated standard and associated 2 ...

Vga-cable.jpg,

VGA Video Graphics Array (VGA) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the PC industry within three years. The term can no ...

3.5mm.jpg, TRRS D4_video_connector.jpg, D-Terminal

Digital video

Digital video signal formats have been adopted, including serial digital interface (SDI),

Digital Visual Interface Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a com ...

(DVI),

High-Definition Multimedia Interface High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller ...

(HDMI) and

DisplayPort DisplayPort (DP) is a digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). It is primarily used to connect a video source to a display device su ...

Interface. BNC_connector_%28male%29.jpg, Serial digital interface (SDI) Dvi-cable.jpg,

(DVI) HDMI-Connector.jpg,

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controlle ...

Displayport-cable.jpg,

Transport medium

Video can be transmitted or transported in a variety of ways including wireless

terrestrial television Terrestrial television or over-the-air television (OTA) is a type of television broadcasting in which the signal transmission occurs via radio waves from the terrestrial (Earth-based) transmitter of a TV station to a TV receiver having an ante ...

as an analog or digital signal, coaxial cable in a closed-circuit system as an analog signal. Broadcast or studio cameras use a single or dual coaxial cable system using serial digital interface (SDI). See

for information about physical connectors and related signal standards. Video may be transported over networks and other shared digital communications links using, for instance, MPEG transport stream,

SMPTE 2022 SMPTE 2022 is a standard from the Society of Motion Picture and Television Engineers (SMPTE) that describes how to send digital video over an IP network. Video formats supported include MPEG-2 and serial digital interface The standard was introduc ...

and

SMPTE 2110 SMPTE 2110 is a suite of standards from the Society of Motion Picture and Television Engineers (SMPTE) that describes how to send digital media over an IP network. SMPTE 2110 is intended to be used within broadcast production and distribution fac ...

Display standards

Digital television

Digital television Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative adva ...

broadcasts use the MPEG-2 and other

s and include: * ATSC – United States,

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

* Digital Video Broadcasting (DVB) –

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

* ISDB – Japan **

ISDB-Tb ISDB-T International, or SBTVD, short for Sistema Brasileiro de Televisão Digital ( en, Brazilian Digital Television System), is a technical standard for digital television broadcast used in Brazil, Argentina, Peru, Botswana, Chile, Honduras, Ve ...

– uses the MPEG-4 video coding format –

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

* Digital Multimedia Broadcasting (DMB) –

Analog television

Analog television broadcast standards include: * Field-sequential color system (FCS) – US, Russia; obsolete *

Multiplexed Analogue Components Multiplexed Analogue Components (MAC) was an analog television standard where luminance and chrominance components were transmitted separately. This was an evolution from older color TV systems (such as PAL or SECAM) where there was interferen ...

(MAC) – Europe; obsolete * Multiple sub-Nyquist sampling encoding (MUSE) – Japan *

–

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, Japan ** EDTV-II "Clear-Vision" - NTSC extension, Japan *

–

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

Oceania Oceania (, , ) is a geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern and Western hemispheres, Oceania is estimated to have a land area of and a population of around 44.5 million ...

PAL-M PAL-M is the analogue TV system used in Brazil since 19 February 1972. At that time, Brazil was the first South American country to broadcast in colour. Colour TV broadcast began on 19 February 1972, when the TV networks Globo and Bandeirantes t ...

– PAL variation,

PAL-N Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

– PAL variation,

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...

and

Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...

PALplus PALplus (or ''PAL+'') is an analogue television broadcasting system aimed to improve and enhance the PAL format by allowing 16:9 (or 1.77:1) aspect ratio broadcasts, while remaining compatible with existing television receivers, defined by Internat ...

– PAL extension,

* RS-343 (military) *

–

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

, former

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

Central Africa Central Africa is a subregion of the African continent comprising various countries according to different definitions. Angola, Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, the Republic of the Congo ...

CCIR System A CCIR System A was the 405-line analog broadcast television system adopted in the UK and Ireland. System A service started in 1936 and was discontinued in 1985. Specifications Some of the important specs are listed below. A frame is the t ...

CCIR System B CCIR System B (originally known as the "Gerber Standard") was the 625-line VHF analog broadcast television system which at its peak was the system used in most countries. It's usually associated with CCIR System G for UHF broadcasts. It is most ...

* CCIR System G * CCIR System H *

CCIR System I CCIR System I is an analogue broadcast television system. It was first used in the Republic of Ireland starting in 1962 as the 625-line broadcasting standard to be used on VHF Band I and Band III, sharing Band III with 405-line System A signals ...

* CCIR System M 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 metadata and synchronization information. 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

Computer display standard Computer display standards are a combination of aspect ratio, display size, display resolution, color depth, and refresh rate. They are associated with specific expansion cards, video connectors and monitors. History Various computer displa ...

s specify a combination of aspect ratio, display size, display resolution, color depth, and refresh rate. A

list of common resolutions This article lists computer monitor screen resolutions that are defined by standards or in common use. Most of them use certain preferred numbers. Computer graphics ; Pixel aspect ratio (PAR): The horizontal to vertical ratio of each pixel. ; ...

is available.

Recording

Early television was almost exclusively a live medium with some programs recorded to film for distribution of historical purposes using

Kinescope Kinescope , shortened to kine , also known as telerecording in Britain, is a recording of a television program on motion picture film, directly through a lens focused on the screen of a video monitor. The process was pioneered during the 194 ...

. The analog

was commercially introduced in 1951. The following list is in rough chronological order. All formats listed were sold to and used by broadcasters, video producers or consumers; or were important historically. * 2" Quadruplex videotape (

1956) * VERA (

BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...

...

History

Analog video

Digital video

Characteristics of video streams

Number of frames per second

Interlaced vs progressive

Aspect ratio

Color model and depth

Video quality

Video compression method (digital only)

Stereoscopic

Formats

Analog video

Digital video

Transport medium

Display standards

Digital television

Analog television

Computer displays

Recording

Digital encoding formats

See also

References

External links