I just installed a Quadro P620 in my Plex server and got transcoding to work with 4k HDR movies. The server is running Unraid, and my player is the Android app on a Hisense TV running Android TV natively. The account I'm using with both the server and the client has a Plex Pass.

Now I'm trying to watch a HEVC 4K HDR movie (Your Name) in Japanese with subtitles.

The subs are PGS, with a lot of effects (following the screen, replacing text on a phone/sheet of paper, etc) so converting them to SRT would lose a lot of charm. But when I'm transcoding, the movie buffers every 10-15 seconds.

I get that I need to transcode the movie/subtitles and transcoding is hard on the GPU, but what I don't understand is that GPU Statistics is giving me a pretty low usage from Plex when transcoding.

GPU load never goes over 10%, memory usage is at around 40%. The encoder stays under 20% and the decoder under 10% at all time.

Is there a reason why I can't max the GPU usage if I'm always buffering?

I also tried to use Kodi with the Plex for Kodi plugin to get direct play with the PGS subtitles but it didn't work.

Thanks for any help/information you can give me!

My last resort will be to hard-code the subtitles but I would love to try to make transcoding work before.

EDIT: Both Plex on Android TV and Plex on the Firestick support direct play with PGS subs, after re-installing the app Plex stopped trying to burn the subs in the movie. Now I can direct play the movie on my 4K TV and transcode 100% on GPU for my 1080p and the subs are sent as sidecar.