Video is an electronic medium for the recording,

copying Copying is the duplication of information or an wiktionary:artifact, artifact based on an instance of that information or artifact, and not using the process that originally generated it. With Analog device, analog forms of information, copying is ...

, playback,

broadcasting Broadcasting is the data distribution, distribution of sound, audio audiovisual content to dispersed audiences via a electronic medium (communication), mass communications medium, typically one using the electromagnetic spectrum (radio waves), ...

, and display of moving

visual The visual system is the physiological basis of visual perception (the ability to detect and process light). The system detects, transduces and interprets information concerning light within the visible range to construct an image and buil ...

media Media may refer to: Communication * Means of communication, tools and channels used to deliver information or data ** Advertising media, various media, content, buying and placement for advertising ** Interactive media, media that is inter ...

. Video was first developed for

mechanical television Mechanical television or mechanical scan television is an obsolete television system that relies on a mechanism (engineering), mechanical scanning device, such as a rotating disk with holes in it or a rotating mirror drum, to scan the scene and ...

systems, which were quickly replaced by

cathode-ray tube A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms on an oscilloscope, a ...

(CRT) systems, which, in turn, were replaced by flat-panel displays of several types. Video systems vary in

display resolution The display resolution or display modes of a digital television, computer monitor, or other 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 resoluti ...

aspect ratio The aspect ratio of a geometry, geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side—the ratio of width to height, when the rectangl ...

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

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic ...

optical disc An optical disc is a flat, usuallyNon-circular optical discs exist for fashion purposes; see shaped compact disc. disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid o ...

computer files A computer file is a resource for recording data on a computer storage device, primarily identified by its filename. Just as words can be written on paper, so too can data be written to a computer file. Files can be shared with and transferred b ...

, and network streaming.

Etymology

The word ''video'' comes from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

verb ''video,'' meaning to see or ''videre''. And as a noun, "that which is displayed on a (television) screen,"

History

Analog video

Video developed from facsimile systems developed in the mid-19th century. Early mechanical video scanners, such as the Nipkow disk, were

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

ed as early as 1884, however, it took several decades before practical video systems could be developed, many decades after

film A film, also known as a movie or motion picture, is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, emotions, or atmosphere through the use of moving images that are generally, sinc ...

. Film records using a sequence of miniature photographic images visible to the eye when the film is physically examined. Video, by contrast, encodes images electronically, turning the images into analog or digital electronic signals for transmission or recording. Video technology was first developed for

systems, which were quickly replaced by

(CRT)

television Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...

systems. Video was originally exclusively live technology. Live video cameras used an electron beam, which would scan a photoconductive plate with the desired image and produce a voltage signal proportional to the brightness in each part of the image. The signal could then be sent to televisions, where another beam would receive and display the image.

Charles Ginsburg Charles Paulson Ginsburg (July 27, 1920 – April 9, 1992) was an American engineer and the leader of a research team at Ampex which developed one of the first practical videotape recorders. Biography Ginsburg was born on July 27, 1920, in San ...

led an

Ampex Ampex Data Systems Corporation is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name ''AMPEX'' is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excell ...

research team to develop 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 signal, 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. ...

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 filmstoc ...

s by writing the camera's electrical signal onto magnetic

videotape Videotape is magnetic tape used for storing video and usually Sound recording and reproduction, sound in addition. Information stored can be in the form of either an analog signal, analog or Digital signal (signal processing), digital signal. V ...

. Video recorders were sold for $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 AV sources and can play back the recording after rewinding. The use of a VCR to reco ...

(VCR) decks and tapes into the

consumer market A consumer is a person or a group who intends to order, or use purchased goods, products, or services primarily for personal, social, family, household and similar needs, who is not directly related to entrepreneurial or business activities. Th ...

Digital video

Digital video is capable of higher quality and, eventually, a much lower cost than earlier analog technology. After the commercial introduction of the DVD in 1997 and later the

Blu-ray Disc Blu-ray (Blu-ray Disc or BD) is a Digital media, digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of ...

in 2006, sales of videotape and recording equipment plummeted. Advances in

computer A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...

technology allow even inexpensive

personal computer A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ...

s and

smartphone A smartphone is a mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as multi ...

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. 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 drives, SSDs, ...

and allowing programmers and broadcasters to move to tapeless production. The advent of digital broadcasting and the subsequent

digital television transition The digital television transition, also called the digital switchover (DSO), the analogue switch/sign-off (ASO), the digital migration, or the analogue shutdown, is the process in which older analogue television broadcasting technology is con ...

are 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 Dynamics (from Greek δυναμικός ''dynamikos'' "powerful", from δύναμις ''dynamis'' " power") or dynamic may refer to: Physics and engineering * Dynamics (mechanics), the study of forces and their effect on motion Brands and ent ...

and color gamuts, along with the introduction of high-dynamic-range digital intermediate data formats with improved

color depth Color depth, also known as bit depth, is either the number of bits used to indicate the color of a single pixel, or the number of bits used for each color component of a single pixel. When referring to a pixel, the concept can be defined as bit ...

, has caused digital video technology to converge with film technology. the use of

digital camera A digital camera, also called a digicam, is a camera that captures photographs in Digital data storage, digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film or film stock. Dig ...

s in Hollywood has surpassed the use of film cameras.

Characteristics of video streams

Number of frames per second

Frame rate Frame rate, most commonly expressed in frame/s, or FPS, is typically the frequency (rate) at which consecutive images (Film frame, frames) are captured or displayed. This definition applies to film and video cameras, computer animation, and moti ...

'', 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 for new professional cameras. PAL standards (Europe, Asia, Australia, etc.) and

SECAM SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''sequential colour memory''), is an analog color television system that was used in France, Russia and some other countries or territories of Europe and Africa. ...

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

NTSC NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170. In 1953, a second ...

standards (United States, Canada, Japan, etc.) specify 29.97 frame/s. Film is shot at a 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 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. Th ...

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 the 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 Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations o ...

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 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, the overall spatial resolution is degraded by simple line doubling—artifacts, such as flickering or comb effects in moving parts of the image, 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, VHS, Laserdisc, digital television (HDTV) when in the 1080 ...

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 A liquid-crystal-display television (LCD TV) is a television set that uses a liquid-crystal display to produce images. It is by far the most widely produced and sold type of television display. LCD TVs are thin and light, but have some disadvanta ...

, digital

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

, or plasma panel. Deinterlacing cannot, however, produce

video quality Video quality is a characteristic of a video passed through a video transmission or processing system that describes perceived video degradation (typically compared to the original video). Video processing systems may introduce some amount of disto ...

that is equivalent to true progressive scan source material.

Aspect ratio

Aspect ratio The aspect ratio of a geometry, geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side—the ratio of width to height, when the rectangl ...

describes the proportional relationship between the width and height of video screens and video picture elements. All popular video formats are rectangular, and this can be described by a ratio between width and height. The ratio of 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 The Academy ratio of 1.375:1 (abbreviated as 1.37:1) is an aspect ratio (image), aspect ratio of a film frame, frame of 35 mm movie film, 35 mm film when used with negative pulldown, 4-perf pulldown.Monaco, James. ''How to Read a Film: The A ...

) is 1.375:1.

Pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...

s on computer monitors are usually square, but pixels used in

digital video Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises ...

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 organizati ...

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. 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 Reportgrowing 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 In color science, 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 ...

uses 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 YIQ is the color space used by the analog NTSC color TV system. ''I'' stands for ''in-phase'', while ''Q'' stands for ''quadrature'', referring to the components used in quadrature amplitude modulation. Other TV systems used different color spa ...

is used in NTSC television, YUV is used in PAL television,

YDbDr YDbDr, sometimes written YD_BD_R, is the colour space used in the SECAM (adopted in France and some countries of the former Eastern Bloc) analog colour television broadcasting standard. It is very close to YUV (used on the PAL system) and it ...

is used by SECAM television, and

YCbCr YCbCr, Y′CbCr, also written as YCBCR or Y′CBCR, is a family of color spaces used as a part of the color image pipeline in digital video and digital photography, photography systems. Like YPbPr, YPBPR, it is based on RGB primaries; the two ...

is used for digital video. The number of distinct colors a pixel can represent depends on the

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 Chrominance, chroma information than for luma (video), luma information, taking advantage of the human visual system's lower acuity for color differences t ...

(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 the 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 Video quality is a characteristic of a video passed through a video transmission or processing system that describes perceived video degradation (typically compared to the original video). Video processing systems may introduce some amount of disto ...

can be measured with formal metrics like peak signal-to-noise ratio (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 fie ...

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

ITU-T The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...

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-pur ...

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 (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 Image compression is a type of data compression applied to digital images, to reduce their cost for computer data storage, storage or data transmission, transmission. Algorithms may take advantage of visual perception and the statistical properti ...

. 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 ...

and other techniques. The most common modern compression standards are

MPEG-2 MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression methods ...

, used for DVD, Blu-ray, 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.ITU Radio Regulations, Section IV. Radio Stations and Systems ...

, and

MPEG-4 MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related ...

, used for AVCHD, mobile phones (3GP), and the Internet.

Stereoscopic

Stereoscopic video for

3D film 3D films are motion pictures made to give an illusion of three-dimensional solidity, usually with the help of special glasses worn by viewers. 3D films were prominently featured in the 1950s in American cinema and later experienced a worldwide r ...

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

, where one channel is overlaid with two color-coded layers. This left and right layer technique is occasionally used for network broadcasts 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 that synchronize to the video to alternately block the image for each eye, so the appropriate eye sees the correct frame. This method is most common in computer

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

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). 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 represe ...

. Many analog and digital recording formats are in use, and

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 Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted form ...

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 of digital video content, such as in a data file or bitstream. It typically uses a standardized video compression algorithm, most commonly based on ...

, for which a number is available.

Analog video

Analog video is a video signal represented by one or more

analog signal An analog signal (American English) or analogue signal (British and Commonwealth English) is any continuous-time signal representing some other quantity, i.e., ''analogous'' to another quantity. For example, in an analog audio signal, the ins ...

s. Analog color video signals include

luminance Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls wit ...

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

, PAL, and

, it is called composite video. Analog video may be carried in separate channels, as in two-channel S-Video (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, TV program (), or simply a TV show, is the general reference to any content produced for viewing on a television set that is broadcast via over-the-air, satellite, and cable, or distributed digitally on streaming plat ...

applications. Composite-video-cable.jpg, Composite video
(single channel RCA) Close-up_of_S-video_female_connector.jpg, S-Video
(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) SCART_20050724_002.jpg,

SCART SCART (also known as or , especially in France, 21-pin EuroSCART in marketing by Sharp Corporation, 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 ...

Vga-cable.jpg, VGA 3.5mm.jpg, TRRS D4_video_connector.jpg, D-Terminal

Digital video

Digital video Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises ...

signal formats have been adopted, including

serial digital interface Serial digital interface (SDI) is a family of digital video Interface (computing), interfaces first standardized by SMPTE (The Society of Motion Picture and Television Engineers) in 1989. For example, ITU-R BT.656 and SMPTE 259M define digital ...

(SDI), Digital Visual Interface (DVI), High-Definition Multimedia Interface (HDMI) and

DisplayPort DisplayPort (DP) is a digital interface used to connect a video source, such as a Personal computer, computer, to a display device like a Computer monitor, monitor. Developed by the Video Electronics Standards Association (VESA), it can also car ...

Interface. BNC_connector_%28male%29.jpg,

Serial digital interface Serial digital interface (SDI) is a family of digital video Interface (computing), interfaces first standardized by SMPTE (The Society of Motion Picture and Television Engineers) in 1989. For example, ITU-R BT.656 and SMPTE 259M define digital ...

(SDI) Dvi-cable.jpg, Digital Visual Interface (DVI) HDMI-Connector.jpg,

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gam ...

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 content is signal transmission, transmitted via radio waves from the terrestrial (Earth-based) transmitter of a TV station to a TV rece ...

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

(SDI). See List of video connectors 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 MPEG transport stream (MPEG-TS, MTS) or simply transport stream (TS) is a standard digital container format for transmission and storage of audio, video, and Program and System Information Protocol (PSIP) data. It is used in broadcast syst ...

, SMPTE 2022 and SMPTE 2110.

Display standards

Digital television

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

broadcasts use the

and other

s and include: * ATSC – United States,

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Korea Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically Division of Korea, divided at or near the 38th parallel north, 3 ...

Digital Video Broadcasting Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) o ...

(DVB) –

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

ISDB Integrated Services Digital Broadcasting (ISDB; Japanese: , ''Tōgō dejitaru hōsō sābisu'') is a Japanese broadcasting standard for digital television (DTV) and digital radio. ISDB supersedes both the NTSC-J analog television system and ...

–

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

** ISDB-Tb – uses the MPEG-4 video coding format –

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Digital multimedia broadcasting Digital multimedia broadcasting (DMB) is a digital radio transmission technology developed in South Korea as part of the national information technology, IT project for sending multimedia such as TV, radio and datacasting to mobile devices s ...

(DMB) –

Analog television

Analog television Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, instantaneous phase and frequency, ...

broadcast standards include: * Field-sequential color system (FCS) – US, Russia; obsolete * Multiplexed Analogue Components (MAC) – Europe; obsolete *

Multiple sub-Nyquist sampling encoding MUSE (Multiple sub-Nyquist Sampling Encoding), commercially known as Hi-Vision (a contraction of HIgh-definition teleVISION) was a Japanese analog high-definition television system, with design efforts going back to 1979. Traditional interlaced v ...

(MUSE) – Japan *

–

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

** EDTV-II Clear-Vision - NTSC extension, Japan * PAL –

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Oceania Oceania ( , ) is a region, geographical region including Australasia, Melanesia, Micronesia, and Polynesia. Outside of the English-speaking world, Oceania is generally considered a continent, while Mainland Australia is regarded as its co ...

** PAL-M – PAL variation,

** PAL-N – PAL variation,

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

and

Uruguay Uruguay, officially the Oriental Republic of 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 the Río de la Plata to the south and the A ...

** PALplus – PAL extension,

* RS-343 (military) *

–

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, former

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

Central Africa Central Africa (French language, French: ''Afrique centrale''; Spanish language, Spanish: ''África central''; Portuguese language, Portuguese: ''África Central'') is a subregion of the African continent comprising various countries accordin ...

* CCIR System A * CCIR System B * CCIR System G * CCIR System H * CCIR System I * 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 dis ...

s specify a combination of aspect ratio, display size, display resolution, color depth, and refresh rate. A list of common resolutions is available.

Recording

Early television was almost exclusively a live medium, with some programs recorded to film for historical purposes using Kinescope. 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. * VERA (

BBC The British Broadcasting Corporation (BBC) is a British public service broadcaster headquartered at Broadcasting House in London, England. Originally established in 1922 as the British Broadcasting Company, it evolved into its current sta ...

experimental format ca. 1952) * 2" Quadruplex videotape (

1956) * 1" Type A videotape (

) * 1/2" EIAJ (1969) * U-matic 3/4" (

Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...

) * 1/2" Cartrivision ( Avco) * VCR, VCR-LP, SVR * 1" Type B videotape ( Robert Bosch GmbH) * 1" Type C videotape (

, Marconi and

) * 2" Helical Scan Videotape ( IVC) (1975) *

Betamax Betamax (also known as Beta, and stylized as the Greek letter Beta, β in its logo) is a discontinued consumer analog Videotape, video cassette recording format developed by Sony. It was one of the main competitors in the videotape format war ag ...

(Sony) (1975) * VHS ( JVC) (1976) * Video 2000 (

Philips Koninklijke Philips N.V. (), simply branded Philips, is a Dutch multinational health technology company that was founded in Eindhoven in 1891. Since 1997, its world headquarters have been situated in Amsterdam, though the Benelux headquarter ...

) (1979) * 1/4" CVC ( Funai) (1980) *

Betacam Betacam is a family of half-inch professional videocassette products developed by Sony in 1982. In colloquial use, ''Betacam'' singly is often used to refer to a Betacam camcorder, a Betacam tape, a Betacam video recorder or the format itself. ...

(Sony) (1982) * VHS-C ( JVC) (1982) * HDVS (Sony) (1984) * Video8 (

) (1986) * Betacam SP (Sony) (1987) *

S-VHS S-VHS, the common initialism for Super VHS, is an analog video cassette format introduced by JVC in 1987 as an improved version of the VHS (Video Home System) format. S-VHS improved image quality by increasing the bandwidth of the luminance ...

( JVC) (1987) * Pixelvision (

Fisher-Price Fisher-Price, Inc. is an American company that produces educational toys for infants, toddlers and preschoolers, headquartered in East Aurora, New York, East Aurora, New York (state), New York. It was founded in 1930 during the Great Depression ...

) (1987) * UniHi 1/2" HD (1988) * Hi8 (Sony) (mid-1990s) * W-VHS ( JVC) (1994) Digital video tape recorders offered improved quality compared to analog recorders. * Betacam IMX (

) * D-VHS ( JVC) * D-Theater * D1 (

) * D2 (

) * D3 * D5 HD * D6 (

) *

Digital-S Digital-S, later known as D-9, is a professional digital videocassette format created by JVC in 1995. It is a direct competitor to Sony's Digital Betacam. Its name was changed to D-9 in 1999 by the SMPTE. It was used to a small extent in Eu ...

D9 ( JVC) *

Digital Betacam Betacam is a family of half-inch professional videocassette products developed by Sony in 1982. In colloquial use, ''Betacam'' singly is often used to refer to a Betacam camcorder, a Betacam tape, a Betacam video recorder or the format itself. ...

(

) * Digital8 (

) * DV (including DVC-Pro) * HDCAM (

) * HDV * ProHD ( JVC) * MicroMV * MiniDV Optical storage mediums offered an alternative, especially in consumer applications, to bulky tape formats. *

(

) * China Blue High-definition Disc (CBHD) * DVD (was

Super Density Disc 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 kin ...

, DVD Forum) * Professional Disc * Universal Media Disc (UMD) (

) * Enhanced Versatile Disc (EVD, Chinese government-sponsored) *

HD DVD HD DVD (short for High Density Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video.

(

NEC is a Japanese multinational information technology and electronics corporation, headquartered at the NEC Supertower in Minato, Tokyo, Japan. It provides IT and network solutions, including cloud computing, artificial intelligence (AI), Inte ...

and

Toshiba is a Japanese multinational electronics company headquartered in Minato, Tokyo. Its diversified products and services include power, industrial and social infrastructure systems, elevators and escalators, electronic components, semiconductors ...

) * HD-VMD * Capacitance Electronic Disc *

Laserdisc LaserDisc (LD) is a home video format and the first commercial optical disc storage medium. It was developed by Philips, Pioneer Corporation, Pioneer, and the movie studio MCA Inc., MCA. The format was initially marketed in the United State ...

( MCA and

) * Television Electronic Disc ( Teldec and

Telefunken Telefunken was a German radio and television producer, founded in Berlin in 1903 as a joint venture between Siemens & Halske and the ''AEG (German company), Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ("General electricity company"). Prior to ...

) * VHD ( JVC) *

Video CD Video CD (abbreviated as VCD, and also known as Compact Disc Digital Video), (not to be confused with CD Video which is a type of Laserdisc) is a home video format and the first format for distributing films on standard optical discs. The f ...

Digital encoding formats

A video codec is

software Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital comput ...

or hardware that compresses and decompresses

. In the context of video compression, ''

codec A codec is a computer hardware or software component that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder o ...

'' is a

portmanteau In linguistics, a blend—also known as a blend word, lexical blend, or portmanteau—is a word formed by combining the meanings, and parts of the sounds, of two or more words together.

of ''encoder'' and ''decoder'', while a device that only compresses is typically called an '' encoder'', and one that only decompresses is a ''decoder''. The compressed data format usually conforms to a standard

. The compression is typically

lossy In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...

, meaning that the compressed video lacks some information present in the original video. A consequence of this is that decompressed video has lower quality than the original, uncompressed video because there is insufficient information to accurately reconstruct the original video. *

(

) * H.261 (

) * H.263 (

) * H.264/MPEG-4 AVC (

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

) * H.265 * M-JPEG (

) *

MPEG-1 MPEG-1 is a Technical standard, standard for lossy compression of video and Audio frequency, audio. It is designed to compress VHS-quality raw digital video and CD audio down to about 1.5 Mbit/s (26:1 and 6:1 compression ratios respectively ...

(

) *

(

) *

(

) * Ogg-

Theora Theora is a free lossy video compression format. It was developed by the Xiph.Org Foundation and distributed without licensing fees alongside their other free and open media projects, including the Vorbis audio format and the Ogg contai ...

VP8 VP8 is an open format, open and royalty-free Video coding format, video compression format released by On2 Technologies in 2008. Initially released as a Proprietary software, proprietary successor to On2's previous VP7 format, VP8 was released a ...

WebM WebM is an audiovisual media file format. It is primarily intended to offer a royalty-free alternative to use in the HTML video and the HTML audio elements. It has a sister project, WebP, for images. The development of the format is sponsored by ...

* VC-1 (

SMPTE The Society of Motion Picture and Television Engineers (SMPTE) (, rarely ), founded by Charles Francis Jenkins in 1916 as the Society of Motion Picture Engineers or SMPE, is a global professional association of engineers, technologists, and e ...

)

References

External links

Format Descriptions for Moving Images
{{Authority control Digital television High-definition television Display technology Television terminology History of television Media formats Data compression

Etymology

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

See also

References

External links