Dolby TrueHD and Dolby MAT with or without Atmos should work. Sounds like (pun intended) you're running on ARC instead of eARC. Is there an eARC setting in your AVR? What model is it? Are you using a HDMI cable "with Ethernet"?So I just did some more testing with the Shield connected directly to my LG CX with eARC and passthrough enabled and yes can confirm no DTS/DTS-HD and for that matter no Dolby TrueHD/Atmos either. So this means that I can't take advantage of Xbox One X ALLM and VRR support AND get Atmos at the same time as that would require connecting the console directly to the TV (ALLM and VRR options are greyed out when connected to the AVR) and since LG in their infinite wisdom decided to annex support for lossless audio from their CX televisions.