Coordinated Video Timings

Coordinated Video Timings (VESA-2013-3 v1.2[1]) is a standard by VESA which defines the timings of the component video signal. Initially intended for use by computer monitors and video cards, the standard made its way into consumer televisions.

The parameters defined by standard include horizontal blanking and vertical blanking intervals, horizontal frequency and vertical frequency (collectively, pixel clock rate or video signal bandwidth), and horizontal/vertical sync polarity.

History

The standard was adopted in 2002 and superseded the Generalized Timing Formula.

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. 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 monitors are being used, since such displays typically do not require these pauses in the picture data. This mode is only defined for vertical frequency of 60 Hz in revision 1.1.

In revision 1.2, released in 2013, a new RB2 mode has been added which further reduces blanking interval and allows for unlimited vertical refresh rates, 4K/5K/8K resolutions, 0.001 MHz pixel clock precision, and 1000/1001 modifier for ATSC/NTSC video timing modes.

Bandwidth

Example data rates required by various display resolutions using common timing methods in Gbit/s
Resolution × color depth @ frame rate CVT CVT-RCVT-R2 CEA-861-F
1280 × 720 @ 60 Hz 1.79 1.54 1.45 1.78
1920 × 1080 @ 60 Hz 4.15 3.33 3.20 3.56
2560 × 1440 @ 60 Hz 5.80 5.63 -
3840 × 2160 @ 30 Hz 6.18 7.13
3840 × 2160 @ 60 Hz 12.54 14.26
5120 × 2880 @ 60 Hz 22.18 -
7680 × 4320 @ 30 Hz 24.82 28.51
7680 × 4320 @ 60 Hz 49.65 57.02
For 24-bit RGB and YCbCr 4:4:4 × 24  bpp color encodings.
Multiply by 1.25, 1.5, or 2 to calculate bandwidth for 30/36/48 bit bpp, divide by 1.5 for YCbCr 4:2:2, divide by 2 for YCbCr 4:2:0.

See also

References

  1. ↑ http://www.vesa.org/vesa-standards/standards-summaries/

External links


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