Kodi 18.9 + FireTV 4k/nVidia Shield + HLG - does it work ?
I recently downloaded BBC's Perfect Planet rip, which is HDR in HLG format.
If I put these mkv files on USB stick and play back through TV set's (Samsung 2018 QE55Q9FN) built-in media player, then it correctly plays it as HLG HDR content (I can verify it through Picture->Expert Settings in TV's menu - HLG EOTF is being displayed).
However if I try to play back these files via Kodi 18.9, running either on FireTV stick 4K or on nVidia Shield 2017, the content is played back as SDR only (TV says BT.1886 EOTF is being used).
Content looks darker, no HDR effects and there's slight greenish tint.
Fire TV stick and Shield are connected to TV set via Onkyo TX-RZ740 A/V receiver which, of course supports HDMI 2.0b/HLG.
HLG content on these two Android plays back fine though - some YouTube HDR movies are encoded as HLG and they play back fine as HLG on TV.
Long story short - is this Kodi limitation/does Kodi 18.9 support playing back HLG content on Android boxes ?
Correction: Youtube HLG videos do not work on Shield, they are displayed as SDR. So Shield probably does not support HLG (?).
But they do work on FireTV Stick 4K - A/V receiver displays "HLG" pop-up as well as EOTF/Gamma setting in TV set's meny switches to HLG.
What does that question have to do with Tvheadend? You should probably ask that in a Kodi forum, chances to get an answer there are much higher.