I just opened an issue on GitHub: https://github.com/MichaIng/DietPi/issues/3152
FeatHub votings look fine, we’ll have a look soon.
Awesome. Thank you. 
For reference: https://github.com/MichaIng/DietPi/issues/3152
moved to 6.32 
unfortunately priorities shifted. Probably next version it might be in 
I made it possible for jellyfin to transcode using GPU with VAAPI. So I think I should let you know my experience.
Originally, I just want to setup a ffmpeg-webui (GitHub - Sub-7/FFmpegUI: FFmpegUI is a graphical web interface for the famous FFmpeg.), and this script offers an hardware-acceleration-option with VAAPI, I just ran the script and found that I can transcode movies through the webui using gpu fastly. When transcoding, I noticed that the cpu consuming is low in htop and gpu consuming is high in intel_gpu_top.
After that, I found that my jellyfin could use hardware transcoding normally. My device is an intelNUC.
I will be glad if this can help you a little
Not far away anymore https://github.com/MichaIng/DietPi/pull/3687