I posted something similar in the IOS forum but this is probably a better place to ask for help.
I have PMS installed on a NAS - a WD PR2100. I have an ATV3 and i use it to play PMS movies via airplay, using the IOS app on my iPhone.
In the original release (that came with my NAS), PMS would always down mixed 5.1 audio to stereo. I upgraded to a later release, and it worked! In all supplemental releases however, it is back to transcoding 5.1 audio to stereo again. This happens regardless of the source format - DD, DTS or AAC, it simply won't output 5.1 audio.
I've tried reverting to the release where it worked, but the issue remains. I suspect a later release edited the config files on my NAS to dictate that airplay or ATV3 should have audio down mixed to stereo, and it's somehow not being updated or reverted when i install another release.
So my question is - does anyone have a fix for this?
Follow up question
i have a feeling i may be able to edit the config files if i can gain access to the root files on my NAS via SSH - applying a fix similar to this: http://forums.plex.tv/discussion/241257/no-more-dolby-digital-in-atv-option-in-pms-plexconnect/p1 however i've not done this before.