[NiteBike]

Long time user, new forum account

The current issue I am working on is making everything in my desktop setup play nicely with my LG C2 television (model OLED42C2PUA)
This is a pretty sweet TV with an OLED panel that operates a full 4K DolbyVision picture @ 120Hz.

Of course, 120Hz is pretty new so I believe I may be running into issues with my GPU talking to the TV and properly negotiating capabilities.
I have a Sapphire NITRO+ Radeon RX 5700 XT 8GB for GPU at the moment. It is self-reporting HDMI version 2.0, so the connection to the TV is simply not fast enough to do 4K+HDR+120FPS.
I have verified all cabling is HDMI 2+ capable using an Xbox Series X (which is new enough to output the full bandwidth signal, unlike my PC).

Ideally, I like to just leave Windows driving this TV at the highest quality 60 HZ signal possible at all times if I can. I'm not honestly sure what that would be, given the panoply of color formats and bit depths and stuff available to use.

Currently, if I have HDR turned on with my LG TV and I launch Kodi, it seems to not understand that it's in HDR mode. If I play a video file with HDR10 (BT.2020 colorspace), the first run of the file results in super blown-out video output until I hit stop.
When the player is stopped, Kodi then switches Windows' HDR mode off for the TV. If I re-run the same video file a second time without doing anything else, Kodi trips Windows' HDR mode back On and plays the video file, which then displays correctly.

I'm feeling especially confused about the option "Use 10 bit for SDR" found in Settings>System>Display and how that comes into this (if at all).

When it comes to SDR playback, if I'm looking for "best visual quality", would I want the higher quality 10-bit video surface going out to a display which has HDR turned on?
Also, along similar lines, since I like to make Kodi look fancy, wouldn't I want to run the menu / library stuff in HDR10 if possible?

Hopefully I haven't missed something super obvious regarding this stuff 🤷

[CrystalP]

There is a correction in v21 for the AMD problem of blown out picture when the display is already in HDR mode, so the first playback will work and you can keep the TV in HDR mode at all times if you want.

People who care about calibration and accuracy let Kodi switch Windows HDR mode on/off since HDR and SDR can be calibrated on the TV separately and more accurately that way.

SDR will play even when the screen is in HDR, but it is tonemapped (expanded in that case), so a little transformed.
Same with the GUI, it's not actual HDR but tonemapped SDR. It looks a bit different, it's up to you which you prefer. Eventually the GUI will show thumbnails and other elements in true HDR but we're not there yet.

In v20 "Use 10 bit for SDR" matters a bit if you're tone mapping HDR to SDR, but that's not your situation. For SDR, the effect borders on placebo (you can't create 2 extra bits of precision out of thin air - there may be a slight difference for SDR encoded in 10 bit hevc/avc for example, but it's not like it's preserving original 10 bit data).

Except for gaming you probably don't need run the screen @120Hz just because you can. It creates additional load on the GPU. The GUI is plenty fluid already at 60HZ, but it's up to you.