I have several shows with built in subtitles rather than external subtitle files. I'm using the Emby Roku app to play these titles. I've noticed that when a file is direct play, I can select subtitles but the subtitles never actually appear.
I understand PGS subtitles will trigger transcoding so they can be burned in. I'm fine with that however it seems there is no option to prefer that over direct play. It seems since the Roku is capable of direct playing these titles that is what Emby has