xineliboutput and VDPAU so I assume what you actually mean by mkv is being able to play back HD or greater content using VDPAU for decoding and xineliboutput to get the decoded frames to your tv.
Correct, my 4K mkv files are using H.265 codecs, HD files are using H.264.
Since dumping Nvidia I haven't kept up with what their current cards capabilities are so I can't advise on an Nvidia card that does HEVC/h265. My NUC handles it great though! ;)
I didn't understand which player/plugin you advise in VDR.
- MPlayer was very good but no longer works...
- Media Player in Xineliboutput is convenient but little buggy under VDPAU...
I originally used mplayer, then mplayer2, and lastly mpv player. The vdr-mplayer plugin + mpv player has worked great. All you have to do to switch from mpv is just change your mplayer.sh (or whatever you call your player script) from using the mplayer bin to mpv bin.