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Mechanical television

mechanicalelectromechanical televisionBaird System
Video was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) systems which were later replaced by flat panel displays of several types. Video technology was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) television systems, but several new technologies for video display devices have since been invented.
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, to scan the scene and generate the video signal, and a similar mechanical device at the receiver to display the picture.

Flat-panel display

flat panel displayflat panelflat panel displays
Video was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) systems which were later replaced by flat panel displays of several types.
Flat-panel displays are electronic viewing technologies used to enable people to see content (still images, moving images, text, or other visual material) in a range of entertainment, consumer electronics, personal computer, and mobile devices, and many types of medical, transportation and industrial equipment.

Cathode-ray tube

CRTcathode ray tubecathode ray tubes
Video was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) systems which were later replaced by flat panel displays of several types. Video technology was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) television systems, but several new technologies for video display devices have since been invented.
An image is produced by controlling the intensity of each of the three electron beams, one for each additive primary color (red, green, and blue) with a video signal as a reference.

Video tape recorder

videotape recorderVTRvideo recorder
Charles Ginsburg led an Ampex research team developing one of the first practical video tape recorder (VTR).
A video tape recorder (VTR) is a tape recorder designed to record and playback video and audio material on magnetic tape.

Videotape

videocassettevideo tapevideo cassette
In 1951 the first video tape recorder captured live images from television cameras by converting the camera's electrical impulses and saving the information onto magnetic video tape.
Videotape is magnetic tape used for storing video and usually sound in addition.

Videocassette recorder

VCRvideo cassette recorderVCRs
However, prices gradually dropped over the years; in 1971, Sony began selling videocassette recorder (VCR) decks and tapes into the consumer market.
A videocassette recorder, VCR, or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other source on a removable, magnetic tape videocassette, and can play back the recording.

Digital video

videodigitalDV
The use of digital techniques in video created digital video, which allows higher quality and, eventually, much lower cost than earlier analog technology. Pixels on computer monitors are usually square, but pixels used in digital video often have non-square aspect ratios, such as those used in the PAL and NTSC variants of the CCIR 601 digital video standard, and the corresponding anamorphic widescreen formats.
Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data.

Video quality

qualityfull reference metricmodels
Deinterlacing cannot, however, produce video quality that is equivalent to true progressive scan source material. Video quality can be measured with formal metrics like Peak signal-to-noise ratio (PSNR) or through subjective video quality assessment using expert observation.
Video quality is a characteristic of a video passed through a video transmission/processing system, a formal or informal measure of perceived video degradation (typically, compared to the original video).

Television

TVtelevisedtelevisions
Video technology was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) television systems, but several new technologies for video display devices have since been invented.
In 1907, Russian scientist Boris Rosing used a CRT in the receiving end of an experimental video signal to form a picture.

Deinterlacing

deinterlacedeinterlacedDe-interlacing
A procedure known as deinterlacing can optimize the display of an interlaced video signal from an analog, DVD or satellite source on a progressive scan device such as an LCD television, digital video projector or plasma panel.
Both video and photographic film capture a series of frames (still images) in rapid succession; however, television systems read the captured image by serially scanning the image sensor by lines (rows).

Scan line

scanlinescan linesscanlines
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.
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.

Rec. 601

ITU-R BT.601BT.601CCIR
Pixels on computer monitors are usually square, but pixels used in digital video often have non-square aspect ratios, such as those used in the PAL and NTSC variants of the CCIR 601 digital video standard, and the corresponding anamorphic widescreen formats.
601 or BT.601 (or its former name, CCIR 601''') is a standard originally issued in 1982 by the CCIR (an organization which has since been renamed as the International Telecommunication Union – Radiocommunication sector) for encoding interlaced analog video signals in digital video form.

NTSC

analog30panalogue broadcasting
PAL standards (Europe, Asia, Australia, etc.) and SECAM (France, Russia, parts of Africa etc.) specify 25 frame/s, while NTSC standards (USA, Canada, Japan, etc.) specify 29.97 frame/s.
NTSC color encoding is used with the System M television signal, which consists of 30⁄1.001 (approximately 29.97) interlaced frames of video per second.

Broadcasting

broadcastbroadcasterbroadcasters
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media.
Television broadcasting (telecast), experimentally from 1925, commercially from the 1930s: an extension of radio to include video signals.

Ampex

Ampex CorporationAmpex HS-100 modelAmpex Records
Charles Ginsburg led an Ampex research team developing one of the first practical video tape recorder (VTR).
Starting in the early 1950s, RCA, Bing Crosby and others tried to record analog video on very fast-moving magnetic tape.

YCbCr

YC B C R Y'CbCrcolor matrix
There are several such representations in common use: YIQ is used in NTSC television, YUV is used in PAL television, YDbDr is used by SECAM television and YCbCr is used for digital video.
YCbCr, Y′CbCr, or Y Pb/Cb Pr/Cr, also written as YC B C R or Y'C B C R, is a family of color spaces used as a part of the color image pipeline in video and digital photography systems.

Line doubler

line doublingde-interlacingdisplaying each line of pixels twice
When displaying a natively interlaced signal on a progressive scan device, overall spatial resolution is degraded by simple line doubling—artifacts such as flickering or "comb" effects in moving parts of the image which appear unless special signal processing eliminates them.
A line doubler is a device used to deinterlace video signals prior to display.

Subjective video quality

psycho-visual optimizationsratings obtained by human viewerssubjective quality assessment
Video quality can be measured with formal metrics like Peak signal-to-noise ratio (PSNR) or through subjective video quality assessment using expert observation.
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 and therefore related to the field of Quality of Experience.

Display device

displayvideo monitorbezel
Video technology was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) television systems, but several new technologies for video display devices have since been invented.
2-dimensional displays that cover a full area (usually a rectangle) are also called video displays, since it is the main modality of presenting video.

Optical disc

optical mediaoptical data storagedisc
Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, and network streaming.
The LaserDisc format stored analog video signals for the distribution of home video, but commercially lost to the VHS videocassette format, due mainly to its high cost and non-re-recordability; other first-generation disc formats were designed only to store digital data and were not initially capable of use as a digital video medium.

Digital cinematography

digitallydigital filmdigital
, with the increasing use of high-resolution video cameras with improved dynamic range and color gamuts, and high-dynamic-range digital intermediate data formats with improved color depth, modern digital video technology is converging with digital film technology.
While there is no clear technical distinction that separates the images captured in digital cinematography from video, the term "digital cinematography" is usually applied only in cases where digital acquisition is substituted for film acquisition, such as when shooting a feature film.

Magnetic tape

tapetapesanalog tape
Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, and network streaming.
Many saw the potential of making the same improvements in recording the video signals used by television.

Video clip

online videovideo clipsclips
Many analog and digital recording formats are in use, and digital video clips can also be stored on a computer file system as files, which have their own formats.
Video clips are short clips of video, usually part of a longer recording.

Video coding format

video compression formatvideo compression standardvideo compression
In addition to the physical format used by the data storage device or transmission medium, the stream of ones and zeros that is sent must be in a particular digital video coding format, of which a number are available (see List of video coding formats).
A video coding format (or sometimes video compression format) is a content representation format for storage or transmission of digital video content (such as in a data file or bitstream).

Motion compensation

motion estimationmotion compensatedmotion-compensated
Likewise, temporal redundancy can be reduced by registering differences between frames; this task is known as interframe compression, including motion compensation and other techniques.
In reference to a video file, this means much of the information that represents one frame will be the same as the information used in the next frame.