Ok. For reasons I can’t explain I had to update my nVidia drivers to the latest, and now both Labyrinth and Da Vinci Code playback fine.
now a bit of a rant:
I can’t explain why every other video I’ve ripped with DeUHD had no issues at all; only what I ripped with MakeMKV. Makes no sense to me whatsoever.
the downside of course is nVidia and Microsoft can’t get their s**t together and produce a consistent experience. I was on nVidia 385.69 and everything worked perfectly (excepting the recent rips with MakeMKV): Video went into Full Screen Exclusive Mode, 3D MVC decoding worked, HDR worked. Stopping video playback and everything was restored properly including turning HDR back off since it looks like ass on the desktop.
With the new nVidia drivers, HDR does not disengage any longer once i playback an HDR encoded movie. Worse there seems to be some random instability if I move from 3D MVC movie back to a 4K movie, JRiver/Madvr seem to lock up at a black screen with the JRiver playback menu flickering.
I’m also convinced the latest HD Audio driver from nVidia has done something to low frequency (bass). Hopefully I can compensate and re-adjust crossover and volume on the sub.
hate updating drivers.