We've seen the issues of limited subtitles and more when folk compare playing on a tablet or PC versus the HDTV.
It appears you are about to learn more about DLNA and its limitations.
I'm using Plex Media Server on my PC running Ubuntu 12.04. It works fine when I stream movie directly from PC to my LG TV. Sometime I stream the same movie to my iPad. And here I noticed the difference. If movie has subtitles or different languages being on iPad client I could select that movie, then select small 'i' icon and it allows me to select another language or modify subtitles. When I watching the same movie on my LG smart TV using Media Link utility it does not have the option to modify those settings. I tried to check it on my Ubuntu server but also didn't find that option?
Could someone please explain me if it could be changed on Ubuntu side and what is the procedure?