HDR & colour
HLG (Hybrid Log-Gamma)
The broadcast HDR format from BBC/NHK used by TV channels and YouTube; no metadata.
What is it?
HLG is an HDR curve designed for live television: it is backwards-compatible with SDR displays and needs no metadata. Used by BBC iPlayer, Sky, YouTube HDR, many cameras and sports broadcasts. Older HDR10-only displays and projectors often do not understand HLG and show a flat, washed-out picture.
Why it matters with the HDfury Vertex²
The HDfury Vertex² can translate HLG into HDR10 in real time — it injects HDR10 (PQ) metadata so a display without HLG support switches into its HDR mode — or simply strip the HLG flag. It also does this automatically only when the connected display lacks HLG in its EDID.
How to use it on the Vertex²
Web server → HDR/DV → tick 'Use custom HDR for TX0 and TX1 when input is HLG' (always) or '…when input is HLG and display has no HLG support' (automatic). Set EOTF to SMPTE ST 2084 in the custom metadata. 'Disable output HDR when input is HLG' removes the flag instead.
Related terms
- HDR10 — The baseline HDR format: 10-bit, PQ curve, BT.2020 with static metadata.
- EOTF / PQ (SMPTE ST 2084) — The brightness curve of HDR: PQ for HDR10/Dolby Vision, HLG for broadcast, gamma for SDR.
- HDR metadata: MaxCLL, MaxFALL, mastering display — The numbers inside an HDR10 signal that tell a display how bright the content is.