Rec. 2100
ITU-R Recommendation BT.2100, more commonly known by the abbreviations Rec. 2100 or BT.2100, introduced high-dynamic-range television (HDR-TV) by recommending the use of the perceptual quantizer (PQ [SMPTE ST 2084]) or hybrid log–gamma (HLG) transfer functions instead of the traditional "gamma" previously used for SDR-TV. It defines various aspects of HDR-TV such as display resolution (HDTV and UHDTV), frame rate, chroma subsampling, bit depth, color space, color primaries, white point, and transfer function.