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59-837: ReGIS was first introduced on the VT125 in July 1981, followed shortly thereafter by the VK100 "GIGI" which combined the VT125 display system with composite video output and a BASIC interpreter. Later versions of the VT series included ReGIS, often with color support as well. This included the VT240 and 241 and the VT330 and 340 . ReGIS is also supported by a small number of terminal emulator systems. ReGIS replaced an earlier system known as waveform graphics that had been introduced on

118-427: A 405 , 525 or 625 line interlaced black and white or color signal, on a single channel, unlike the higher-quality S-Video (two channels) and the even higher-quality YPbPr (three channels). A yellow RCA connector is typically used for composite video, with the audio being carried on separate additional L/R RCA connectors. In professional settings, or on devices that are too small for an RCA connector, such as

177-435: A macrograph and then recalled using the @ operator. Up to 10,000 characters of code can be stored in the macros, each named with a single letter. The advantage is that the series of operations in the macro can be invoked by sending only two characters over the serial port, as opposed to the entire sequence of commands. This code enters ReGIS mode and uses the S command to erase the screen with (E) and then turns on

236-580: A 5-pin DIN connector for audio. The BNC connector, in turn, post dated the PL-259 connector featured on first-generation VCRs. Video cables are 75 ohm impedance, low in capacitance. Typical values run from 52 pF/m for an HDPE -foamed dielectric precision video cable to 69 pF/m for a solid PE dielectric cable. The active image area of composite and s-video signals are digitally stored at 720x576i25 PAL and 720x480i29.7 (or 720x488) pixels. This does not represent

295-459: 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 , SMPTE 2022 and SMPTE 2110 . Digital television broadcasts use

354-524: A digital camera, other types of connectors can be used. Composite video is also known by the initials CVBS for Composite Video Baseband Signal or Color, Video, Blanking and Sync , or is simply referred to as SD video for the standard-definition television signal it conveys. There are three dominant variants of composite video signals, corresponding to the analog color system used ( NTSC , PAL , and SECAM ), but purely monochrome signals can also be used. A composite video signal combines, on one wire,

413-433: 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 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,

472-439: A new location, and uses the "F"ill command to wrap a "C"ircle. The fill command could wrap any number of commands within its parentheses, allowing it to fill complex shapes. It also allowed the inclusion of a "temporary write" that allowed the programmer to set the fill style within the fill, and abandon it as soon as it ended. Composite video Composite video is an baseband analog video format that typically carries

531-442: A number is available. Analog video is a video signal represented by one or more analog signals . Analog color video signals include luminance (Y) and chrominance (C). When combined into one channel, as is the case among others with NTSC , PAL , and SECAM , 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 formats. Analog video

590-438: A particular refresh rate, display resolution , and color space . Many analog and digital recording formats are in use, and digital video clips can also be stored on a computer file system as files, which have their own formats. In addition to the physical format used by the data storage device or transmission medium, the stream of ones and zeros that is sent must be in a particular digital video coding format , for which

649-433: 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 led an Ampex research team to develop one of the first practical video tape recorders (VTR). In 1951, the first VTR captured live images from television cameras by writing

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708-507: 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 ) is 1.375:1. Pixels on computer monitors are usually square, but pixels used in digital video often have non-square aspect ratios, such as those used in

767-407: A sampled signal and losslessly reproduces composite video signals using PCM encoding of the analog signal on the magnetic tape . With the advent of affordable higher sampling speed analog to digital converters, realtime composite to YUV sampled digital sampling has been possible since the 1980s and raw waveform sampling and software decoding since the 2010s. A number of so-called extensions to

826-425: A signal from an analog modulator. However, composite video has an established market for both devices that convert it to channel 3/4 outputs , as well as devices that convert standards like VGA to composite, therefore it has offered opportunities to repurpose older composite monitors for newer devices. The process of modulating RF with the original video signal, and then demodulating the original signal again in

885-402: A signal in (roughly) composite format: LaserDiscs and type C videotape for example store a true composite signal modulated, while consumer videotape formats (including VHS and Betamax ) and commercial and industrial tape formats (including U-matic ) use modified composite signals FM encoded (generally known as color-under ). The professional D-2 videocassette format digitally storing

944-605: A single command. The interpreter is not case sensitive. Some ReGIS terminals support color, using a series of registers. These can be set with the S command using a variety of color input styles. s(m3(r100g0b0)) sets color register ("map") 3 to "r"ed using the RGB color system, while s(m3(h120l50s100)) does the same using the HLS system. The W command likewise sets a wide variety of different styles, mostly for masking, fills and brushes. Finally, ReGIS allows commands to be stored into

1003-456: Is in rough chronological order. All formats listed were sold to and used by broadcasters, video producers, or consumers; or were important historically. Digital video tape recorders offered improved quality compared to analog recorders. Optical storage mediums offered an alternative, especially in consumer applications, to bulky tape formats. A video codec is software or hardware that compresses and decompresses digital video . In

1062-455: 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

1121-517: 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 that appear unless special signal processing eliminates them. A procedure known as deinterlacing can optimize

1180-527: Is reduced by registering differences between parts of a single frame; this task is known as intraframe compression and is closely related to image compression . Likewise, temporal redundancy can be reduced by registering differences between frames; this task is known as interframe compression , including motion compensation and other techniques. The most common modern compression standards are MPEG-2 , used for DVD , Blu-ray, and satellite television , and MPEG-4 , used for AVCHD , mobile phones (3GP), and

1239-422: 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. Video can be interlaced or progressive . In progressive scan systems, each refresh period updates all scan lines in each frame in sequence. When displaying

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1298-445: Is the generic Device Control String (DCS) used in the VT series of terminals and is also used for a variety of other commands. The digit following the DCS is optional and specifies a mode, in this case, mode 0. Mode 0 is the default and picks up drawing where it left off, 1 resets the system to a blank slate, and 2 and 3 are the same as 0 and 1, but leave a single line of text at the bottom of

1357-502: Is used in NTSC television, YUV is used in PAL television, YDbDr is used by SECAM television, and YCbCr is used for digital video. The number of distinct colors a pixel can represent depends on the color depth expressed in the number of bits per pixel. A common way to reduce the amount of data required in digital video is by chroma subsampling (e.g., 4:4:4, 4:2:2, etc.). Because the human eye

1416-440: Is used in both consumer and professional television production applications. Digital video signal formats have been adopted, including serial digital interface (SDI), Digital Visual Interface (DVI), High-Definition Multimedia Interface (HDMI) and DisplayPort Interface. Video can be transmitted or transported in a variety of ways including wireless terrestrial television as an analog or digital signal, coaxial cable in

1475-494: The Latin video (I see). Video developed from facsimile systems developed in the mid-19th century. Early mechanical video scanners, such as the Nipkow disk , were patented as early as 1884, however, it took several decades before practical video systems could be developed, many decades after film . Film records using a sequence of miniature photographic images visible to the eye when

1534-499: The MPEG-2 and other video coding formats and include: Analog television broadcast standards include: 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

1593-537: The VT55 and later used on the VT105 . DEC normally provided backward compatibility with their terminals, but in this case, the waveform system was simply dropped when ReGIS was introduced. ReGIS consists of five primary drawing commands and a selection of status and device control commands. ReGIS mode is entered by specifying the escape code sequence ESC P 0 p , and exited with ESC \ . The sequence ESC P

1652-459: The AM and FM bands. A gated and filtered signal derived from the color subcarrier , called the burst or colorburst , is added to the horizontal blanking interval of each line (excluding lines in the vertical sync interval ) as a synchronizing signal and amplitude reference for the chrominance signals. In NTSC composite video, the 3.58 MHz burst signal is inverted in phase (180° out of phase) from

1711-463: The Internet. Stereoscopic video for 3D film and other applications can be displayed using several different methods: 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

1770-489: 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 . Mary Meeker , a partner at Silicon Valley venture capital firm Kleiner Perkins Caufield & Byers , highlighted

1829-516: The TV, introduces losses including added noise or interference. For these reasons, it is best to use composite connections instead of RF connections if possible for live signals and sample the source FM RF signal for recorded formats. Some video equipment and modern televisions have only RF input. Video#Analog video Video is an electronic medium for the recording, copying , playback, broadcasting , and display of moving visual media . Video

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1888-459: The Y coordinates are "folded" so odd and even coordinates are the same location on the screen. Later models, starting with the VT240 and VT241, provide the full 480 pixel vertical resolution. The coordinate system can also be set by the user. Coordinates can be pushed or pulled from a stack, and every command allows the stack to be used as a parameter, the B parameter pushes the current coordinates on

1947-450: The building blocks of the blanking interval. 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. Early television was almost exclusively a live medium, with some programs recorded to film for historical purposes using Kinescope . The analog video tape recorder was commercially introduced in 1951. The following list

2006-425: The camera's electrical signal onto magnetic videotape . 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 (VCR) decks and tapes into the consumer market . Digital video is capable of higher quality and, eventually, a much lower cost than earlier analog technology. After

2065-460: The chrominance and luminance components of the signal. This is usually seen when chrominance is transmitted with high bandwidth, and its spectrum reaches into the band of the luminance frequencies. Comb filters are commonly used to separate signals and eliminate these artifacts from composite sources. S-Video and component video avoid this problem as they maintain the component signals physically separate. Most home analog video equipment record

2124-553: The commercial introduction of the DVD in 1997 and later the Blu-ray Disc in 2006, sales of videotape and recording equipment plummeted. Advances in computer technology allow even inexpensive personal computers and smartphones to capture, store, edit, and transmit digital video, further reducing the cost of video production and allowing programmers and broadcasters to move to tapeless production . The advent of digital broadcasting and

2183-461: The composite video signal is typically connected using an RCA connector, normally yellow. It is often accompanied with red and white connectors for right and left audio channels respectively. BNC connectors and higher quality coaxial cable are often used in professional television studios and post-production applications. BNC connectors were also used for composite video connections on early home VCRs , often accompanied by either RCA connector or

2242-438: The context of video compression, codec is a portmanteau 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 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

2301-509: The display of an interlaced video signal from an analog, DVD, or satellite source on a progressive scan device such as an LCD television , digital video projector , or plasma panel. Deinterlacing cannot, however, produce video quality that is equivalent to true progressive scan source material. Aspect ratio 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

2360-688: The entire composite signal. This can then be comb-filtered or chroma-decoded to a color image on a standard computer or via DAC played back to a TV. Composite is no longer the universal standard it once was for consumers after the digital era began phasing out analog CRT displays and virtually all consumer devices moved to using HDMI . Modified versions of composite such as 960H (960x576) are still in wide use for CCTV systems today in consumer use alongside fpv drones . Some devices, such as videocassette recorders (VCRs), video game consoles , and home computers output composite video. This may then be converted to FM RF with an RF modulator that generates

2419-445: 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

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2478-441: 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 mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) television systems. Video was originally exclusively live technology. Live video cameras used an electron beam, which would scan

2537-466: The growth of vertical video viewing in her 2015 Internet Trends Report – growing from 5% of video viewing in 2010 to 29% in 2015. Vertical video ads like Snapchat 's are watched in their entirety nine times more frequently than landscape video ads. The color model 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

2596-447: The harmonics in the baseband luma signal, rather than both being in separate continuous frequency bands alongside each other in the frequency domain. The signals may be separated using a comb filter . In other words, the combination of luma and chrominance is indeed a frequency-division technique, but it is much more complex than typical frequency-division multiplexing systems like the one used to multiplex analog radio stations on both

2655-432: 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

2714-406: The modulated color signal overlaps that of the baseband signal, and separation relies on the fact that frequency components of the baseband signal tend to be near harmonics of the horizontal scanning rate, while the color carrier is selected to be an odd multiple of half the horizontal scanning rate; this produces a modulated color signal that consists mainly of harmonic frequencies that fall between

2773-622: The number of distinct points at which the color changes. Video quality can be measured with formal metrics like peak signal-to-noise ratio (PSNR) or through subjective video quality assessment using expert observation. Many subjective video quality methods are described in the ITU-T 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

2832-660: The proper carrier (often for channel 3 or 4 in North America , channel 36 in Europe ). Sometimes this modulator is built into the product (such as video game consoles, VCRs, or the Atari , Commodore 64 , or TRS-80 CoCo home-computers), is an external unit powered by the computer ( TI-99/4A ), or with an independent power supply. Because of the digital television transition most television sets no longer have analog television tuners but DVB-T and ATSC digital ones. They therefore cannot accept

2891-408: The reference subcarrier. In PAL, the phase of the 4.43 MHz color subcarrier alternates on successive lines. In SECAM, no colorburst is used since phase information is irrelevant. The combining of component signals to form the composite signal does the same, causing a checkerboard video artifact known as dot crawl . Dot crawl is a defect that results from crosstalk due to the intermodulation of

2950-436: The same video. The expert then rates the impaired video using a scale ranging from "impairments are imperceptible" to "impairments are very annoying." Uncompressed video 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

3009-451: The screen for entering commands. All drawing is based on an active pen location. Any command that moves the pen leaves it there for the next operation, similar to the operation of a mechanical plotter . The coordinate system is 0 to 799 in the X axis, and 0 to 479 in Y, with 0,0 in the upper left. In early implementations such as the VK100 and VT125, the actual device resolution is 240 pixels, so

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3068-403: The stack, and E pops it back off again. Coordinates can be specified in absolute or relative terms; There are four main drawing commands and three control commands; Each of these commands uses the various coordinate modes in different ways, and some have additional parameters that are enclosed in parentheses. Commands can be followed by one or more parameters, allowing continued drawing from

3127-455: The subsequent digital television transition 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 and color gamuts , along with the introduction of high-dynamic-range digital intermediate data formats with improved color depth , has caused digital video technology to converge with film technology. Since 2013,

3186-562: The use of digital cameras in Hollywood has surpassed the use of film cameras. Frame rate , the number of still pictures per unit of time of video, ranges from six or eight frames per second ( frame/s ) for old mechanical cameras to 120 or more frames per second for new professional cameras. PAL standards (Europe, Asia, Australia, etc.) and SECAM (France, Russia, parts of Africa, etc.) specify 25 frame/s, while NTSC standards (United States, Canada, Japan, etc.) specify 29.97 frame/s. Film

3245-420: The video information required to recreate a color picture, as well as line and frame synchronization pulses. The color video signal is a linear combination of the luminance (Y) of the picture and a chrominance subcarrier which carries the color information (C), a combination of hue and saturation . Details of the combining process vary between the NTSC, PAL and SECAM systems. The frequency spectrum of

3304-514: The visible TV image can be transmitted using composite video. Since TV screens hide the vertical blanking interval of a composite video signal, these take advantage of the unseen parts of the signal. Examples of extensions include teletext , closed captioning , information regarding the show title, a set of reference colors that allows TV sets to automatically correct NTSC hue maladjustments, widescreen signaling (WSS) for switching between 4:3 and 16:9 display formats, etc. In home applications,

3363-455: The visible cursor with (C1) . P[100,440] moves the pen to 100,440 absolute. V(B),[+100,+0],[+0,-10],[-100,+0],(E) draws a series of lines, first pushing the current pen location onto the stack with (B) , then drawing three lines using relative coordinates, and then using (E) to pop the previously saved location off the stack and draw to it. The result is a rectangle 100 by 10 pixels in size. P[500,300],F(C[+100]) then moves to

3422-475: The whole signal. Hardware typically samples at four times the color subcarrier frequency (4fsc) that includes the vertical blanking interval (VBI). Only commercial video capture devices used in broadcast output images with the extra VBI space. Direct sampling with high-speed ADCs and software time base correction has allowed projects like the open-source CVBS-Decode to create a D-2 like 4fsc stream that preserves and allows full presentation and inspection of

3481-526: Was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems, which, in turn, were replaced by flat-panel displays of several types. Video systems vary in display resolution , aspect ratio , refresh rate , color capabilities, and other qualities. Analog and digital variants exist and can be carried on a variety of media, including radio broadcasts , magnetic tape , optical discs , computer files , and network streaming . The word video comes from

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