jf 10.10.7 Ugreen 4800 plus - Playback failed due to a fatal player error

[fisao]

Hello everyone, 

I have not found a solution to my exact problem in the search functon of this forum and am therefore starting this new thread

I have the following error: 
"Playback Error Playback failed due to a fatal player error."

on the following setup: 
jellyfin 10.10.7 on Ugreen DXP4800plus (32GB RAM)
running the stock OS (UGOS I believe) in version 1.5.0.2628
installed via Docker image 

my file setup is: 
Cache

/config/cache

Logs

/config/log

Metadata

/config/data/metadata

Transcodes

/config/cache/transcodes

Web
/usr/share/jellyfin/web

and I have attached the latest log output for the last three attempts.

- the playback error seems to only occur on x265 HEVC 10bit files 
- when hardware encoding is enabled, for all file formats -> always immediate fail 
- when hardware encoding is disabled -> transcode starts, but is understandably very laggy, so not a solution unfortunately

the cpu on the machine is (I believe):
- Intel Pentium Gold 8505 4400 5 Cores 6 threads with 32 GB of RAM (because I had it available, it is of course overkill)

I see that ffmpeg is exiting with an 187, but I am not knowlegeable enough to understand why in this case

I would be immensely grateful if anybody could give me some pointers as to what could be done to remedy the situation

Please let me know if any additional information that I could provide could help, thank you very much if you can