Standard-dynamic-range video (SDR video) is a video technology which represents light intensity based on the brightness, contrast and color characteristics and limitations of a cathode ray tube (CRT) display. SDR video is able to represent a video or picture's colors with a maximum luminance around 100 cd/m², a black level around 0.1 cd/m² and Rec.709 / sRGB color gamut. It uses the gamma curve as its electro-optical transfer function.

The first CRT television sets were manufactured in 1934 and the first color CRT television sets were manufactured in 1954. The term "standard-dynamic-range video" was adopted to distinguish SDR video from high-dynamic-range video (HDR video), a new technology that was developed in the 2010s to overcome SDR's limits.

Conventional gamma curves:

The linear part of the conventional gamma curve was used to limit camera noise in low light video but is no longer needed with high dynamic range (HDR) cameras. An example of a conventional gamma curve would be Rec. 601:

${\displaystyle E={\begin{cases}4.500L&L<0.018\\1.099L^{0.45}-0.099&L\geq 0.018\end{cases}}}$

ITU-R Recommendation BT.1886 describe the reference EOTF of SDR. It's a gamma curve representing the response of CRT to video signal. It has been published by ITU in 2011.

A transfer function that is closer to Weber's law allows for a larger dynamic range, at the same bit depth, than a conventional gamma curve. HDR standards such as hybrid log–gamma (HLG) and SMPTE ST 2084 allow for a larger dynamic range by using a different transfer function. HLG is compatible with SDR displays.

In some cases the term SDR is also used with a meaning including the standard color gamut (i.e. Rec. 709 / sRGB color primaries). HDR uses wide color gamut (WCG) such as Rec. 2020 or DCI-P3 color primaries.