I am not able to get movies to play 5.1 surround using the latest Plex Media Player. I am running 1.9.6 server version and 2.1.1 for the media player. The movies are all ripped to m4v using handbrake and have AAC and AC3 Passthru tracks. The server is running on a Mac Mini connected to my receiver via optical cable. I have tried all combinations of direct play and streaming on the server but cannot get the Pasthru track to work. These files all play fine using OpenPHT. What am I missing or is this just not possible for the PMP?
Put PMP into its āfullscreen TVā mode
(only possible on the main page using this icon: )

Then click on your user name, pick
Settings - Audio
select
Device Type = Optical (S/PDIF)
and put a checkmark into the boxes Dolby Digital and/or DTS
(depending on what your receiver supports over optical input)
That was it Thank you
this worked for me as well on a my mac mini using Mini-TOSLink out. Surround worked back in the day but stopped a year+ ago . Nothing in the settings would fix it, the mac was set to digital out and VLC plays surround fine. But going into TV mode first and settings as per OttoKernerās post I found the audio Device Type set to āBasicā. Set it āOptical (S/PDIF)ā as per this article and it worked at last!!
Then for an encore I went into the TV mode Video settings and turned off the forced zoom, at last I can see the sides of movies! another setting I couldnāt get right from regular mode.
