Frame rate control (FRC) or temporal dithering is a method for achieving greater

color depth Color depth, 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 a pixel, the concept can be defined as bit ...

particularly in

liquid-crystal display A liquid-crystal display (LCD) is a flat-panel display or other Electro-optic modulator, electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liq ...

s. Older, cheaper, or faster LCDs, especially those using TN, often represent colors using only 6

bit The bit is the most basic unit of information in computing and digital communication. 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 as ...

s per RGB color, or 18 bit in total, and are unable to display the 16.78 million color shades (24-bit truecolor) that contemporary signal sources like

graphics card A graphics card (also called a video card, display card, graphics accelerator, graphics adapter, VGA card/VGA, video adapter, display adapter, or colloquially GPU) is a computer expansion card that generates a feed of graphics output to a displa ...

video game console A video game console is an electronic device that Input/output, outputs a video signal or image to display a video game that can typically be played with a game controller. These may be home video game console, home consoles, which are generally ...

set-top box A set-top box (STB), also known as a cable converter box, cable box, receiver, or simply box, and historically television decoder or a converter, is an information appliance device that generally contains a Tuner (radio)#Television, TV tuner inpu ...

es, and

video camera A video camera is an optical instrument that captures videos, as opposed to a movie camera, which records images on film. Video cameras were initially developed for the television industry but have since become widely used for a variety of other ...

s can output. Instead, they use a temporal

dither Dither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dither is routinely used in processing of both digital audio and video data, and is ofte ...

ing method that combines successive colors in the same pixel to simulate the desired shade. This is distinct from, though can be combined with, spatial dithering, which uses nearby pixels at the same time. FRC cycles between different color shades within each new frame to simulate an intermediate shade. This can create a potentially noticeable 30 Hz (half frame rate) flicker. Temporal dithering tends to be most noticeable in darker tones, while spatial dithering appears to make the individual pixels of the LCD visible. TFT panels available in 2020 often use FRC to display 30-bit deep color or

HDR10 HDR10 Media Profile, more commonly known as 'HDR10'', is an open high-dynamic-range video (HDR) standard announced on 27 August 2015, by the Consumer Electronics Association. It is the most widespread HDR format. HDR10 is not Backward compatibil ...

with 24-bit color panels. Temporal dithering is also implemented in software, for if the display itself does not, as for instance

GPU A graphics processing unit (GPU) is a specialized electronic circuit designed for digital image processing and to accelerate computer graphics, being present either as a discrete video card or embedded on motherboards, mobile phones, personal ...

drivers from both

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational corporation and technology company headquartered in Santa Clara, California and maintains significant operations in Austin, Texas. AMD is a hardware and fabless company that de ...

and

Nvidia Nvidia Corporation ( ) is an American multinational corporation and technology company headquartered in Santa Clara, California, and incorporated in Delaware. Founded in 1993 by Jensen Huang (president and CEO), Chris Malachowsky, and Curti ...

provide the option, enabled by default on some platforms. This method is similar in principle to

field-sequential color system A field-sequential color system (FSC) is a color television system in which the primary color information is transmitted in successive images and which relies on the human vision system to fuse the successive images into a color picture. One field ...

by CBS and other sequential methods, such as used for grays in DLP, and also colors in single-chip 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 The refresh rate, also known as vertical refresh rate, vertical scan rate or vertical frequency in reference to terminology originating with the cathode-ray tubes (CRTs), is the number of times per second that a raster-based display device displa ...

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 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 ...

. 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.

References

{{reflist Display technology

See also

References