ITU-R BT.1886
ITU-R BT.1886 is the reference EOTF of SDR-TV. It is a gamma 2.4 transfer function (a power law with a 2.4 exponent) considered as a satisfactory approximation of the response characteristic of CRT to electrical signal. It has been standardized by ITU in March 2011. It is used for Rec. 709 (HD-TV) and Rec. 2020 (UHD-TV).[1][2]
Definition
BT.1886 EOTF is as follows:[1]
where
![{\displaystyle L=a(\max[(V+b),0])^{\gamma }}](https://wikimedia.org/api/rest_v1/media/math/render/svg/4d09af5b1c1542de78c9fe0fbea0e78fd89bebb2)
- is the screen luminance, in cd/m2.
- is the input video signal level, in the range .
- is the exponent of the power function and equal to 2.4
- is the variable for user gain (legacy “contrast” control)
- is the variable for user black level lift (legacy “brightness” control)
- is the screen luminance for white, in cd/m2.
- is the screen luminance for black, in cd/m2.
![{\displaystyle \left[0,1\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/c57121c2b6c63c0b2f38eb96b1f7a543b5d1c522)
According to ITU, for a better match, can be set to 0.1 for moderate black level settings (e.g. 0.1 cd/m2) or to 0 for lower black levels (e.g. 0.01 cd/m2).[1]
An alternative EOTF has also been provided by ITU for the cases a more precise match of CRT characteristics is required.[1]
See also
References
- ^ a b c d "BT.1886 : Reference electro-optical transfer function for flat panel displays used in HDTV studio production". www.itu.int. Retrieved 2021-11-07.
- ^ "BT.2020 : Parameter values for ultra-high definition television systems for production and international programme exchange". www.itu.int. Retrieved 2021-11-07.