Hi,
This app seems to have the same problem as here for the Android app:
"TrueHD Atmos file -> Emby server -> lan -> LG C9 -> Emby TV app -> eArc HDMI -> Marantz SR5015 -> displays DD+ and not "Atmos" on info
Yet it CAN work because (all the same with Plex):
Same TrueHD file -> Plex server -> lan -> LG C9 -> Plex TV app -> eARC -> AVR -> DOES display "Atmos" on info
So it appears that Emby transcodes the TrueHD audio to D