I'm testing an embedded Ryzen R1505G w/ Vega 3 graphics using the ROHQ performance madvr profile. If I start MC and begin playback, the first video I watch plays back fine. In fact, they all play fine (720p-4K, no dropped frames) using the balanced profile and other more demanding scaling algos (up to Jinc), but I am using the default ROHQ performance settings to eliminate hardware bottlenecks as I debug this problem. I have also tested w/ and w/o hardware acceleration, although hardware acceleration is practically a requirement on such a low-powered machine.
The problem arises after I stop playback or exit the full screen display, the next time I play a video or re-enter full-screen display mode the video is choppy and drops frames. If I restart MC, the same behavior ensues: the first video plays fine and then subsequently it starts dropping frames after I stop and restart playback or exit and reenter display view.
This is similar to the problems I was having on my GTX 1060-powered HTPC w/ HDR videos getting stuck in HDR mode. It seems that madvr isn't fully releasing GPU resources when playback is stopped or full-screen display mode exits, until MC is restarted. On my powerful discrete GPU rig this didn't have a noticeable impact on performance (just the HDR color settings) but on my low-powered Ryzen box it is causing performance problems. Using alternative media players w/ and w/o madvr do not cause this problem and all of my media plays back fine even with more demanding scaling algos in those programs.
During playback my GPU sits at about 65% utilization and my CPU is around 30% w/ HA.
Windows 10 version: 21H1 19043.1147
Driver version: 21.20.21.01-210722a-369924E-RadeonSoftware
MC version: 28.0.44