Synology DS415+, Plex Server 1.5.5.3634
Since a couple of weeks/versions any video with dts audio is suddenly unplayable on iOS and tvOS devices. On iOS the yellow circle spins endlessly, on tvOS the activity wheel spins for a while then the screen shows a thumbnail of the video with a replay button.
On the other hand videos with dts audio are playing fine in the web player in Safari on macOS Sierra. The cpu load on the synology is at 50%, so I assume this is not a server issue but an iOS/tvOS problem.


Above Status screenshots when playing a dts video on an iPhone (not working) and in Plex Web (working). The difference is the transcoding: for iOS the server transcodes to AC3, for the web player to AAC.
I tried every combination of preferences but to no avail.
Anyone else having this problem? What do you need (logs, screenshots) to help?
EDIT: Playback of dts videos on Sony PS3 is working, on Fire TV it’s not working …