Addition:

You may also want to change the user running the container, e.g

  --user=1001:1001 

For hardware transcoding on the server, you also need to give the container access to your GPU, e.g.

  --device=/dev/dri:/dev/dri

And check that the user running the process has the proper permissions:

  $ ls -la /dev/dri 

https://github.com/linuxserver/docker-jellyfin#hardware-acce...