To set permissions on the QNAP, ssh into the NAS as issue a chmod on /dev/dri/*.
Right now I have it set to 777 which is probably overkill. Eventually I will try to do this a little better, adding a video group, adding plex to it, putting /dev/dri/* in that group, and changing permissions to 770, or perhaps less. Not sure right now what the minimum required permissions are, but that would be the target.
Also not sure about making this change persist across reboots, but I think it is a matter is issuing the necessary commands in an autorun.sh located in the /tmp/config directory. Also not 100% sure of this, but that’s where I am today.
Not everything supports HW transcoding, so you need to look at the Plex dashboard to see what is HW vs. SW transcoding during playback.
If you are transcoding say 7.1 ATMOS down to 2-Channel audio it uses the CPU (not GPU) which on smaller boxes (if you have say the i3 version) can be taxing.
Subtitles (depending on how you are doing them) will use CPU transcoding. Using a video container NOT supported by the embedded GPU will use CPU transcoding.
