[Warner306]

I will check which hardware decoding I'm using. Which one is recommended?

Can anyone tell me what's going here? This happens when I try to play 4K mkv via Mpc-HC or Kodi. As soon as playback stops, everything is back to normal. 1080p files play without any issue.

I'm using Nvidia 1050 card with latest drivers. Output is going to JVC projector. Projector automatically goes to HDR mode so I'm guessing it has to something MadVr settings? 

 You didn't know that all HDR video looks like that?

If you are using D3D11 Native hardware decoding, try DXVA2 (copy-back) instead. I can't remember if this fixed it, but I have seen the pink wave before. It looks like bad video decoding, to me.

 It depends on the hardware. Use the one that works.

Yes, bad hardware decoding can corrupt the entire screen during playback. The image is usually green, not pink, but it is the same idea.

If it is not that, then I would suspect a driver bug is the problem. If this PC was upgraded and not new, you need to run a utility like DDU to clean the old drivers and install fresh, new ones. You should also be using the most recent version of madVR. There is a chance that madVR is at fault, but it is not likely if you are using anything besides D3D11 Native decoding. If D3D11 Native is not working, then it is definitely madVR as D3D11 Native was coded in madVR as part of the decoding process. One of the available decoding options should work.