I just read the update to the post saying that the issue has been narrowed down to the NTFS driver. I haven’t used NTFS on linux since the NTFS fuse driver was brand new and still wonky as hell something like 15 years ago, so I don’t know much about it.
However, it sounds like the in kernel driver was still pretty fresh in 5.15, so doing as you have suggested and trying out a 6.5 kernel instead is a pretty good call.
The most impressed I’ve been with hardware encoding and decoding is with the built in graphics on my little NUC.
I’m using a NUC10i5FNH which was only barely able to transcode one vaguely decent bitrate stream in software. It looked like passing the hardware transcoding through to a VM was too messy for me so I decided to reinstall linux straight on the hardware.
The hardware encoding and decoding performance was absolutely amazing. I must have opened up about 20 jellyfin windows that were transcoding before I gave up trying and called it good enough. I only really need about 4 maximum.
The graphics on the 10th generation NUC’s is the same sort of thing that is on the 9th gen and 10th gen desktop cpu’s, so if you have and intel cpu with onboard graphics give it a try.
It’s way less trouble than the last time I built a similar setup with NVidia. I haven’t tried a Radeon card yet, but the jellyfin docs are a bit more negative about AMD.