Frame rate control (FRC) is a method for achieving greater
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 ...
in
TFT LCD displays.
Older
TN panels represented colors using only 6
bit
The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented a ...
s per RGB color, or 18 bit in total, and were unable to display the 16.78 million color shades (24-bit
truecolor) that display devices like
graphics 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 moni ...
s,
video game consoles,
tablet computers and
set-top boxes can output. Instead, they could use a
dithering method that combines adjacent pixels to simulate the desired shade. As of 2021, most TN panels are capable of displaying 24-bit color without any form of dithering.
FRC is a form of temporal dithering which cycles between different color shades with each
new frame to simulate an intermediate shade. This can create a potentially noticeable 30 Hz (half frame rate) flicker. FRC tends to be most noticeable in darker tones, while dithering appears to make the individual pixels of the LCD visible. TFT panels available in 2020 often used FRC to display
30-bit deep color or
HDR10 with 24-bit color panels.
This method is similar in principle to
field-sequential color system by CBS and other sequential color methods such as used in
Digital Light Processing (DLP).
In the demonstration video green and cyan-green are mixed both statically (for reference) and by rapidly alternating. A display with a
refresh rate of at least 60hz is recommended for this video. Pausing the video shows that the perceived color of the bottom-right square during playback is different from the color seen in any individual
frame. In an LCD display that uses FRC the colors that are alternated between would be more similar than those in the demonstration video, further reducing the flicker effect.
See also
*
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 ...
*
LCD television
References
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Display technology