Is there any specific mtu or mss config for jellyfin?

[TheDreadPirate]

I see a lot of transcoding for the external connections. What are your server specs? Hardware and operating system.

I also see Jellyfin Mobile as the phone client. Have you tried Swiftfin? Its a more up-to-date iOS client. Also, 10.8.11 is out and has some fixes. Both for bugs and for security issues.

Can you also share your ffmpeg log with us? Use https://sourceb.in/ instead of pastebin. Found out pastebin is blocked here at my work, so hard to follow up on these.