I have so many issues with the RX6900XT and all are related to HDMI somehow.
I am trying to watch movies from my PC connected to LG OLED via HDMI 2.1 and using madVR to auto detect movie framerate which is usually 24p results in No HD audio at all. No TrueHD, no DTS-HD MA, no Atmos and no DTS:X.
It also happens if I set the system's refresh rate to anything lower than 100hz using ANY media player.
Only when I set refresh rate to 100 or 120hz, I get HD audio fine.
I connect the GPU to the TV then TV to AVR using eARC.
I always use bitstreaming and had no issues with the same exact setup with GTX 1070Ti GPU I upgraded from. I am using MPC-HC with Lav Filters and madVR but the same issue happens with PowerDVD and DVDFab Player and Movies&TV Windows 10 app so it is definitely the RX6900XT.
Anybody has the same issue?
Other issues I have with HDMI 2.1 are here:
https://community.amd.com/t5/drivers-software/rx6900xt-hdmi-2-1-issues/m-p/470047#M143932