will the nvidia shield direct play when using synology 918+ as server and shield as client?

I am asking this question because i read all different things about transcoding. I want to use my synology 918+ as Plex server. The shield i want to use as a client. I want to play HD and 4K movies WITH subtitles (srt, vob or PGS) i read that when using subs in Plex the server always has to transcode. But my NAS cant handle this at this moment (now i am using a PS3 for client)
So i am wondering.. if i will buy a shield and use that as s client instead of my PS3. Will that work. And will i be able to direct play that content?
Thanks in advance