I’m running both plex and jellyfin on the same server with same media and same tv box. My hardware setup is ok, I have surround audio with plex on my avr via toslink. I’m trying to transition to jellyfin but I need to iron these out. Audio in jellyfin is stereo only. In my jellyfin server I have audio set to max 5.1 channels, on the android tv app the audio is set to direct. When I start a movie with plex the avr receives signal and switches to dolby digital or dts mode. When I start playback with jellyfin with the same media the avr switches to stereo. I cannot find any other settings to tweak. Please let me know what am I missing.
What happens on other clients? And how many channels does the source audio track have?
I dont have other client with surround audio system to test this. My test is that the very same movie has surround sound in plex hence my settings in android and on the avr are right.
Did you try disabling audio transcoding?