Video is an electronic medium for the recording,

copying Copying is the duplication of information or an artifact based on an instance of that information or artifact, and not using the process that originally generated it. With analog forms of information, copying is only possible to a limited degree o ...

, playback,

broadcasting Broadcasting is the distribution (business), distribution of sound, audio or video content to a dispersed audience via any electronic medium (communication), mass communications medium, but typically one using the electromagnetic spectrum (radio ...

, 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 (the ...

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 el ...

. 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 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 (oscilloscope), pictur ...

(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 li ...

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 is ...

, 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 ...

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 magne ...

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

(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 device A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...

s have since been invented. Video was originally exclusively a

live Live may refer to: Arts, entertainment, and media Films * ''Live!'' (2007 film), 2007 American film * ''Live'' (2014 film), a 2014 Japanese film *'' ''Live'' (Apocalyptica DVD) Music *Live (band), American alternative rock band * List of albums ...

technology.

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 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 use ...

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). O ...

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, videocassett ...

. 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 Videotape is magnetic tape ...

(VCR) decks and tapes into the

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

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 kin ...

in 1997, and later the

Blu-ray Disc The Blu-ray Disc (BD), often known simply as Blu-ray, is a Digital media, 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 c ...

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

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

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 In the field of professional broadcasting, an end-to-end workflow (from ingest to playout) is called ''tapeless'' when part, or all of it, is made without any use of audio tape recorders or videotape machines; video and audio sources being inges ...

. 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 conv ...

is in the process of relegating analog video to the status of a

legacy technology In computing, a legacy system is an old method, technology, computer system, or application program, "of, relating to, or being a previous or outdated computer system", yet still in use. Often referencing a system as "legacy" means that it paved ...

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 signals, like sound and light. It is measured either as a ratio or as a base-1 ...

and color gamuts, 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 intermediate ...

data formats with improved

color depth Color depth or colour depth (see spelling differences), 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 ...

, has caused digital video technology to converge with film technology. the usage of digital cameras in

Hollywood Hollywood usually refers to: * Hollywood, Los Angeles, a neighborhood in California * Hollywood, a metonym for the cinema of the United States Hollywood may also refer to: Places United States * Hollywood District (disambiguation) * Hollywood, ...

has surpassed use of film cameras.

Characteristics of video streams

Number of frames per second

Frame rate Frame rate (expressed in or FPS) is the frequency (rate) at which consecutive images (frames) are captured or displayed. The term applies equally to film and video cameras, computer graphics, and motion capture systems. Frame rate may also be ca ...

'', 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 ...

progressive Progressive may refer to: Politics * Progressivism, a political philosophy in support of social reform ** Progressivism in the United States, the political philosophy in the American context * Progressive realism, an American foreign policy par ...

. 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 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 of ...

and

CRT CRT or Crt may refer to: Science, technology, and mathematics Medicine and biology * Calreticulin, a protein *Capillary refill time, for blood to refill capillaries *Cardiac resynchronization therapy and CRT defibrillator (CRT-D) * Catheter-re ...

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 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 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 signalling (telecommunication), signal and projects the corresponding image on a projection screen using a lens (optics), lens system. Video projectors use a very bright ultra-high-per ...

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 dist ...

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 geometry, 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 par ...

, 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 The Academy ratio of 1.375:1 (abbreviated as 1.37:1) is an aspect ratio of a frame of 35 mm film when used with 4-perf pulldown.Monaco, James. ''How to Read a Film: The Art, Technology, Language, History and Theory of Film and Media''. Rev. ...

) 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 smal ...

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 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 cin ...

. 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 entrepreneurs ...

, 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 Snapchat is an American multimedia instant messaging app and service developed by Snap Inc., originally Snapchat Inc. One of the principal features of Snapchat is that pictures and messages are usually only available for a short time before the ...

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

Color model and depth

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: typically

YIQ YIQ is the color space used by the analog NTSC color TV system, employed mainly in North and Central America, and Japan. ''I'' stands for ''in-phase'', while ''Q'' stands for ''quadrature'', referring to the components used in quadrature amplitud ...

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. His ...

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 Urugua ...

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-diffe ...

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

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 (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 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 dist ...

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 Commu ...

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 delivers maximum quality, but at a very high

data rate Data rate and data transfer rate can refer to several related and overlapping concepts in communications networks: Achieved rate * Bit rate, the number of bits that are conveyed or processed per unit of time ** Data signaling rate or gross bit 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 storage or transmission. Algorithms may take advantage of visual perception and the statistical properties of image data to provide superior r ...

. 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

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

, used for

, Blu-ray and satellite television, 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 tec ...

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

Stereoscopic

Stereoscopic Stereoscopy (also called stereoscopics, or stereo imaging) is a technique for creating or enhancing the depth perception, illusion of depth in an image by means of stereopsis for binocular vision. The word ''stereoscopy'' derives . Any stere ...

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. They have existed in some form since 1915, but had been largely relegated to a niche in the motion pict ...

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 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 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 (see List of video connectors). A given physical link can carry certain display standards that specify a particular refresh rate,

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

video clip Video clips refer to mostly short videos, most of the time called memes, which are short videos of silly jokes and funny clips, most of the time coming from movies or any entertainment videos such as YouTube. The term is also used more loosely to ...

s can also be stored on a

computer file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...

as files, which have their own formats. In addition to the physical format used by the

data storage device Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are conside ...

or transmission medium, the stream of ones and zeros that is sent must be in a particular digital video coding format, of which a number are available.

Analog video

Analog video is a video signal represented by one or more

analog signal An analog signal or analogue signal (see spelling differences) is any continuous signal representing some other quantity, i.e., ''analogous'' to another quantity. For example, in an analog audio signal, the instantaneous signal voltage varies c ...

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 withi ...

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

and

it is called

composite video Composite video is an analog video signal format that carries standard-definition video (typically at 525 lines or 625 lines) as a single channel. Video information is encoded on one channel, unlike the higher-quality S-Video (two channels) a ...

. Analog video may be carried in separate channels, as in two channel S-Video (YC) and multi-channel component video formats. Analog video is used in both consumer and professional television production applications. Composite-video-cable.jpg,

Composite video Composite video is an analog video signal format that carries standard-definition video (typically at 525 lines or 625 lines) as a single channel. Video information is encoded on one channel, unlike the higher-quality S-Video (two channels) a ...

(single channel RCA) Close-up_of_S-video_female_connector.jpg, S-Video
(2-channel YC) Component-cables.jpg, Component video
(3-channel YPbPr) SCART_20050724_002.jpg, SCART 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 now ...

3.5mm.jpg,

TRRS A phone connector, also known as phone jack, audio jack, headphone jack or jack plug, is a family of electrical connectors typically used for analog signal, analog audio signals. A plug, the Gender of connectors and fasteners, male connect ...

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 (SDI), Digital Visual Interface (DVI), High-Definition Multimedia Interface (HDMI) and DisplayPort Interface. BNC_connector_%28male%29.jpg, Serial digital interface (SDI) Dvi-cable.jpg, Digital Visual Interface (DVI) HDMI-Connector.jpg, HDMI Displayport-cable.jpg, DisplayPort

Transport medium

Video can be transmitted or transported in a variety of ways including wireless terrestrial television 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 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 systems ...

, SMPTE 2022 and SMPTE 2110.

Display standards

Digital television

Digital television broadcasts use the

and other video coding formats and include: *

ATSC Advanced Television Systems Committee (ATSC) standards are an American set of standards for digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard and, like that ...

– United States, Canada, Mexico, Korea *

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) ...

(DVB) – Europe *

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

–

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

** ISDB-Tb – uses the MPEG-4 video coding format – Brazil, Argentina * Digital Multimedia Broadcasting (DMB) – Korea

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 HDTV system, with design efforts going back to 1979. It used dot-interlacing and digital video co ...

(MUSE) – Japan *

– United States, Canada,

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

– Europe, Asia, Oceania ** PAL-M – PAL variation, Brazil ** PAL-N – PAL variation, Argentina, Paraguay and Uruguay ** PALplus – PAL extension, Europe *

RS-343 Here is a list of American Electronic Industries Alliance (EIA) Standards. The EIA ceased operations on February 11, 2011, but the former sectors continue to serve the constituencies of EIA. EIA designated ECA to continue to develop standards f ...

(military) *

– France, former Soviet Union, Central Africa *

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 mostl ...

CCIR System G CCIR System G is an analog broadcast television system used in many countries. There are several systems in use and letter G is assigned for the European UHF system which is also used in the majority of Asian and African countries. (However some ...

CCIR System H CCIR System H is an analog broadcast television system primarily used in Belgium, the Balkans and Malta on the UHF bands. Specifications Some of the important specs are listed below.Reference Data for Radio Engineers, ITT Howard W.Sams Co., N ...

* CCIR System I *

CCIR System M CCIR System M, sometimes called 525–line, monochrome NTSC or NTSC-M, is the analog broadcast television system approved by the FCC (upon recommendation by the National Television Systems Committee - NTSC) for use in the United States since ...

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 standards 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 distribution of 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. *

2" Quadruplex videotape 2-inch quadruplex videotape (also called 2″ quad video tape or quadraplex) was the first practical and commercially successful analog recording video tape format. It was developed and released for the broadcast television industry in 1956 by A ...

(

1956) *

VERA Vera may refer to: Names *Vera (surname), a surname (including a list of people with the name) *Vera (given name), a given name (including a list of people and fictional characters with the name) **Vera (), archbishop of the archdiocese of Tarrag ...

( BBC experimental format ca. 1958) * 1" Type A videotape (

) * 1/2" EIAJ (1969) * U-matic 3/4" ( Sony) * 1/2" Cartrivision ( Avco) * VCR, VCR-LP, SVR * 1" Type B videotape (

Robert Bosch GmbH Robert Bosch GmbH (; ), commonly known as Bosch and stylized as BOSCH, is a German multinational engineering and technology company headquartered in Gerlingen, Germany. The company was founded by Robert Bosch in Stuttgart in 1886. Bosch is 9 ...

) * 1" Type C videotape (

, Marconi and Sony) *

Betamax Betamax (also known as Beta, as in its logo) is a consumer-level analog recording and cassette format of magnetic tape for video, commonly known as a video cassette recorder. It was developed by Sony and was released in Japan on May 10, 1975, ...

(Sony) * VHS (

JVC JVC (short for Japan Victor Company) is a Japanese brand owned by JVCKenwood corporation. Founded in 1927 as the Victor Talking Machine Company of Japan and later as , the company is best known for introducing Japan's first televisions and for ...

) *

Video 2000 Video 2000 (also known as V2000, with the tape standard Video Compact Cassette, or VCC) is a consumer videocassette system and analogue recording standard developed by Philips and Grundig to compete with JVC's VHS and Sony's Betamax video techn ...

( Philips) * 2" Helical Scan Videotape (

IVC IVC can refer to: Places *Invercargill Airport, New Zealand, IATA code * Ivory Coast, UNDP country code *Oflag IV-C, a German World War II prisoner-of-war camp in Colditz Castle Education *Impington Village College *Irvine Valley College *Imperia ...

) * 1/4" CVC ( Funai) * Betacam (Sony) * HDVS (Sony) * Betacam SP (Sony) *

Video8 The 8mm video format refers informally to three related videocassette formats. These are the original Video8 (analog recording) format and its improved successor Hi8 (analog video and analog audio but with provision for digital audio), as well as ...

( Sony) (1986) * S-VHS (

) (1987) * VHS-C (

) *

Pixelvision The PXL2000 is a toy camcorder produced by Fisher-Price in 1987. Designed for maximal economy, it records extremely low-resolution monochrome video and audio, all to compact audio cassette. It was on the market for one year with about 400,0 ...

(

Fisher-Price Fisher-Price 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. The company was founded in 1930 during the Great Depressio ...

) * UniHi 1/2" HD (Sony) *

Hi8 The 8mm video format refers informally to three related videocassette formats. These are the original Video8 (analog recording) format and its improved successor Hi8 (analog video and analog audio but with provision for digital audio), as well as ...

(Sony) (mid-1990s) * W-VHS (

) (1994) Digital video tape recorders offered improved quality compared to analog recorders. *

Betacam IMX 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. All ...

( Sony) * D-VHS (

) *

D-Theater D-VHS is a digital video recording format developed by JVC, in collaboration with Hitachi, Matsushita, and Philips. The "D" in D-VHS originally stood for "Data", but JVC renamed the format as "Digital VHS". Released in 1998, it uses the same ph ...

* D1 ( Sony) * D2 ( Sony) * D3 * D5 HD * D6 ( Philips) * Digital-S D9 (

) *

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. All ...

( Sony) *

Digital8 Digital8 (or Di8) is a consumer digital recording videocassette for camcorders based on the 8 mm video format developed by Sony, and introduced in 1999. The Digital8 format is a combination of the earlier analog Hi8 tape transport with the dig ...

( Sony) * DV (including DVC-Pro) * HDCAM ( Sony) * HDV * ProHD (

) *

MicroMV MicroMV is a proprietary videotape format introduced in October 2001 by Sony. It is the smallest videotape format — 70% smaller than MiniDV or about the size of two US quarter coins; it is also smaller than a Digital8 or DV cassette and slig ...

* MiniDV Optical storage mediums offered an alternative, especially in consumer applications, to bulky tape formats. *

( Sony) * China Blue High-definition Disc (CBHD) *

(was

Super Density Disc The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital media, 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 ...

DVD Forum The DVD Forum is an international organization composed of hardware, software, media and production companies that use and develop the DVD and formerly HD DVD formats. It was initially known as the DVD Consortium when it was founded in 1995. H ...

) * Professional Disc * Universal Media Disc (UMD) ( Sony) *

Enhanced Versatile Disc The enhanced versatile disc (EVD) is an optical-medium-based digital audio/video format, developed by Beijing E-World (a multi-company partnership including SVA, Shinco, Xiaxin, Yuxing, Skyworth, Nintaus, Malata, Changhong, and BBK Electronics), ...

(EVD, Chinese government-sponsored) * HD DVD ( NEC and Toshiba) *

HD-VMD Versatile Multilayer Disc (VMD or HD VMD) was a high-capacity red-laser optical disc technology designed by New Medium Enterprises, Inc. VMD was intended to compete with the blue-laser Blu-ray Disc and HD DVD formats and had an initial capacity ...

* Capacitance Electronic Disc *

Laserdisc The LaserDisc (LD) is a home video format and the first commercial optical disc storage medium, initially licensed, sold and marketed as DiscoVision, MCA DiscoVision (also known simply as "DiscoVision") in the United States in 1978. Its diam ...

(

MCA MCA may refer to: Astronomy * Mars-crossing asteroid, an asteroid whose orbit crosses that of Mars Aviation * Minimum crossing altitude, a minimum obstacle crossing altitude for fixes on published airways * Medium Combat Aircraft, a 5th gene ...

and Philips) *

Television Electronic Disc Television Electronic Disc (TeD) is a discontinued video recording format, released in 1975 by Telefunken and Teldec. The format used flexible foil discs, which spun at 1,500 rpm on a cushion of air. TeD never gained wide acceptance, and co ...

( Teldec and Telefunken) * VHD (

)

Digital encoding formats

A video codec is software or hardware that compresses and decompresses

. In the context of video compression, '' codec'' is a portmanteau of ''encoder'' and ''decoder'', while a device that only compresses is typically called an ''

encoder Encoder may refer to: Electronic circuits * Audio encoder, converts digital audio to analog audio signals * Video encoder, converts digital video to analog video signals * Simple encoder, assigns a binary code to an active input line * Priority e ...

'', and one that only decompresses is a ''decoder''. The compressed data format usually conforms to a standard video coding format. The compression is typically lossy, 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. * CCIR 601 (

) *

H.261 H.261 is an ITU-T video compression standard, first ratified in November 1988. It is the first member of the H.26x family of video coding standards in the domain of the ITU-T Study Group 16 Video Coding Experts Group (VCEG, then Specialists Gro ...

(

) *

H.263 H.263 is a video compression standard originally designed as a low-bit-rate compressed format for videotelephony. It was standardized by the ITU-T Video Coding Experts Group (VCEG) in a project ending in 1995/1996. It is a member of the H.26x fam ...

(

) * H.264/MPEG-4 AVC (

+ ISO) * H.265 *

M-JPEG Motion JPEG (M-JPEG or MJPEG) is a video compression format in which each video frame or interlaced field of a digital video sequence is compressed separately as a JPEG image. Originally developed for multimedia PC applications, Motion JPE ...

( ISO) * MPEG-1 ( ISO) *

(

+ ISO) *

( ISO) *

Ogg Ogg is a free, open container format maintained by the Xiph.Org Foundation. The authors of the Ogg format state that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high-quality d ...

- Theora * VP8- WebM * VC-1 ( SMPTE)

References

External links

* *
Programmer's Guide to Video Systems: in-depth technical info on 480i, 576i, 1080i, 720p, etc.

Format Descriptions for Moving Images
{{Authority control Digital television Film and video technology High-definition television Display technology Television terminology History of television Media formats Articles containing video clips

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