Hybrid Log-Gamma is a backwards-compatible high dynamic range standard that was jointly developed by the BBC and NHK. Instead of starting with an HDR signal, HLG begins with a standard dynamic range (SDR) signal. But what is HLG? Does your TV have it? And why should you care if it does? The best place to start is with HDR (High Dynamic Range): a video. Hybrid Log-Gamma (HLG) is a backwards-compatible high dynamic range (HDR) standard that. Multiple HDR formats can exist in a single TV. Hybrid log gamma, or HLG, is another kind of high dynamic range (HDR), similar to HDR10 and Dolby Vision.