transcoding with gpu

Hello everyone, I have been tinkering with Jellyfin for a while now, but this is my first visit here.


I seemed to have hit a problem that I find hard to solve, involving transcoding with the help of the GPU. I’ve been searching this forum but could not find a thread discussing the same problem.


My setup is:
Hp elitedesk mini 800 G4 met intel UHD Graphics 630
Proxmox with Jellyfin running in an unprivileged LXC container
Qnap TS-253D containing the video files in a shared folder
LG tv with WEBOS and Jellyfin client


The gpu is passed trough to proxmox and bound to the LXC container.
As such, the setup works. The command intel_gpu_top shows that the gpu is working and the film does start to play (before the transcoding the film did not play).
BUT: After about 15 minutes the screen froze. Different attempts to restart the film did not succeed. After I rebooted the LXC container. The film continued where it was halted, but a few minutes later it froze again.

Anybody an idea of what could cause it?