HLG live TV issues


I just started using LiveTV with my Vero 4K+. The backend is a Tvheadend server with DVB-S2 tuners.

One thing which does not work in Kodi is HLG (Tvheadend HTSP Client addon). When I am watching UHD channels with HLG the picture is way too dark (see SES UHD Channel on Astra 19.2E for a FreeTV demo of this effect). I think Kodi/OSMC is not detecting the HLG flag in the stream correctly.

One of the problems might be the fact that my display only supports plain HDR10, it does not have HLG support. So I would have expected that tone mapping would kick in, or did I get this wrong? From my understanding there are basically three options what OSMC/Kodi could do when handling HLG:

  • Trigger HLG mode of display (if supported)
  • On-thy-fly conversion of HLG metadata to HDR10 metadata and trigger HDR mode on display (if HDR10 is supported). Not sure if a conversion is even possible or if tone-mapping to HDR10 would be required here as well.
  • Tone-map to SDR

Is any of this implemented yet? Is this supposed to work right now?

BTW: HDR10 playback is working just fine within OSMC. It properly triggers HDR mode on my TV.

My OSMC version is 2022.03-1

OSMC 2022.03-1 does not have support for some HLG streams. There’s a patch to fix this but it didn’t make it into the release. Would you be interested in testing this for us?

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Hi @grahamh,

yes, I’d like to test the patch if it could really help me in my situation. What exactly does it do? Does it tone-map to SD or does it tone-map to HDR10 in my case (my display does not support HLG)?

Ok I’ll need to make a kernel for you in a standard package. If your display does HDR10 it should convert HLG to HDR10, otherwise HLG->SDR. Since my TV does both I can’t test the HLG->HDR10 conversion.

I’ve added you to a PM where we are testing a new video stack.
You’ll need to test via USB or SD card installation, but it should work well.