H.264 .mkv with DVD Subs - Direct Play

[thbkk]

I just want to understand, why transcodung is needed for DVDSUBS. I changed all settings that Transcoding won't be used because my hardware is only a Raspi4. But some Movies aren't playing because of Subs. So I disabled Subs and then it works. I've seen that DVDSubs are the problem.
With Kodi, VLC it works. 

Why does jellyfin has a problem with direct play and DVDSUBS?