HLG

HLG (Hybrid Log-Gamma, developed by the BBC and NHK, 2016) is an HDR transfer function that is relative and backward-compatible: its lower range looks correct on an ordinary SDR display, so a single broadcast signal serves both HDR and SDR sets without separate feeds. That convenience makes HLG the favourite for live broadcast. It contrasts with PQ, which is absolute — a PQ code value maps to a specific nit level, while HLG’s values are relative to the display’s capability. Both are HDR encodings that pair with the wide Rec.2020 gamut inside the Rec.2100 container; you grade to one or the other depending on the deliverable.

First used in: 3.6 · HDR grading