Convert HLG video to HDR10?

tikker · September 4, 2021

Since neither my Nvidia Shield 2019 nor Plex seem to support HLG, I was wondering if there was a way to map it to HDR10. I found a tool that helps convert HDR10 to HLG (https://github.com/wswartzendruber/hlg-tools), but I'd like to convert HLG to HDR10. I guess it's the reverse process and I'll need to somehow generate a "backwards" LUT?

wswartzendruber · March 31, 2022

It's unfortunate that your devices don't support HLG playback. I suppose that could change as broadcast HDR picks up steam. I know the latest Roku supports HLG at the hardware level.

Anyway, converting from HLG to HDR10/PQ is a fairly straightforward process as far as the math goes. There's really only one LUT that's needed. If you're still interested, I can try to dig one up for you.

Principally, converting from HLG to HDR10/PQ only serves to limit the video. White HDR10/PQ has more dynamic range potential, each video is mastered for a very specific viewing environment. HLG was designed for videos to be viewed in arbitrary conditions and therefore with arbitrary display brightnesses. This is something a lot of technical sites don't mention.