The hybrid log–gamma transfer function is a transfer function jointly developed by the BBC and NHK for high dynamic range display. It is backward compatible with the transfer function of SDR. It was approved as ARIB STD-B67 by the Association of Radio Industries and Businesses. It is also defined in ATSC 3.0, Digital Video Broadcasting UHD-1 Phase 2, and International Telecommunication Union Rec. 2100.
HLG is an HDR format that uses the HLG transfer function, BT.2020 color primaries and a bitdepth of 10-bit. HLG was designed to be backward compatible with SDR UHDTV.
