Here's the summary for the wikipedia article you mentioned in your comment:

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.

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Oh, cool. Another gimmick that we are going to be fighting about which standard to use for the next few decades, making terabytes of libraries seem obsolete, and another convenient excuse for the manufacturers to discontinue old models and keep the TV prices up despite offering no real improvements and manufacturing costs and quality dropping to the floor. Nice.