Coordinated Video Timings (CVT; ''VESA-2013-3 v1.2'') is a standard by
VESA
VESA (), formally known as Video Electronics Standards Association, is an American technical standards organization for computer display standards. The organization was incorporated in California in July 1989To retrieve the information, searc ...
which defines the timings of the
component video signal. Initially intended for use by
computer monitor
A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls.
The di ...
s and
video card
A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer mo ...
s, the standard made its way into consumer
televisions
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 advertising, ...
.
The parameters defined by standard include
horizontal blanking
Horizontal blanking interval refers to a part of the process of displaying images on a computer monitor or television screen via raster scanning. CRT screens display images by moving beams of electrons very quickly across the screen. Once the beam ...
and
vertical blanking interval
In a raster scan display, the vertical blanking interval (VBI), also known as the vertical interval or VBLANK, is the time between the end of the final visible line of a frame or field and the beginning of the first visible line of the next fra ...
s,
horizontal frequency and
vertical frequency (collectively,
pixel clock
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 sm ...
rate or video
signal bandwidth
Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to ''passband bandwidth'' or ''baseband bandwidth''. ...
), and
horizontal/
vertical sync
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, phase and frequency of an analog s ...
polarity.
The standard was adopted in 2002 and superseded the
Generalized Timing Formula Generalized Timing Formula is a standard by VESA which defines exact parameters of the component video signal for analogue VGA display interface.
The video parameters defined by the standard include horizontal blanking (retrace) and vertical bla ...
.
Reduced blanking
CVT timings include the necessary pauses in picture data (known as "blanking intervals") to allow CRT displays to reposition their electron beam at the end of each
horizontal scan line, as well as the
vertical repositioning necessary at the end of each
frame
A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent.
Frame and FRAME may also refer to:
Physical objects
In building construction
*Framing (con ...
. CVT also specifies a mode ("CVT-R") which significantly reduces these blanking intervals (to a period insufficient for CRT displays to work correctly) in the interests of saving video signal bandwidth when modern displays such as
LCD monitor
A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in cont ...
s are being used, since such displays typically do not require these pauses in the picture data.
In revision 1.2, released in 2013, a new "Reduced Blanking Timing Version 2" mode was added which further reduces the horizontal blanking interval from 160 to 80 pixels, increases pixel clock precision from ±0.25 MHz to ±0.001 MHz, and adds the option for a 1000/1001 modifier for ATSC/NTSC video-optimized timing modes (e.g. 59.94 Hz instead of 60.00 Hz or 23.976 Hz instead of 24.000).
CEA-861-H will introduce RBv3.
Bandwidth
See also
*
Extended display identification data Extended Display Identification Data (EDID) and Enhanced EDID (E-EDID) are metadata formats for display devices to describe their capabilities to a video source (e.g. graphics card or set-top box). The data format is defined by a standard published ...
References
External links
VESA free standards- includes free CVT 1.2 timings spreadsheet
Video signal
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