I’ve tried using various subtitles other than SRT that are listed on the Infuse website and the player doesn’t detect any of them as subtitle tracks.
I’ve tried:
MICRODVD
SSA/ASS
TXT (various)
SUB (various)
Just a quick note, many subtitle formats unfortunately use the same file extensions, so the “SUB” listed on the main page could be anything from the MPSub format to the Subviewer format (both of which I’ve tried) and there are far too many that export to TXT for me to even list. It might help to list the full format name instead of the file extension in those cases.
Using the most recent version of Infuse on Apple TV (7.8.4), I’m unsure how to find out if I’m using DLNA or UPnP but I’m using whatever the default is with SMB shares.