Originally Posted by muzikologist
Gotcha. I wasn't aware that the X1X's Atmos output could shift from lossless to lossy. Just experimented with some Blu-rays and I did manage to get lossless Atmos from Game of Thrones season 1 (regular 1080p Blu-ray) via the CX/Vertex2.
When the Xbox is connected directly to the Anthem MRX 1120, the Atmos soundtracks for the UHD Blu-rays One Amazing Day and Spider-Man: Homecoming are also reported as lossless, but the lossless indicator does not show up when those discs are played on the Xbox connected to the CX/Vertex2. I don't know why that should be (if it's got anything to do with 4K vs. 1080p Blu-rays, for instance).
As for games, I tried Ori: Will of the Wisps, in which the lossless Atmos indicator does not show up whether the Xbox is connected to the TV or the AVR. Does anyone know of any lossless Atmos-enabled Xbox games? I wonder whether only on-disc Atmos is lossless on the X1X.
Just to be clear, the MRX 1120's display reads "Atmos" for all the above. I can only tell the difference between lossy and lossless by pressing the info button and cycling through to the page with sample rate (which is always 48KHz) and bit rate (which either reads "Lossless" or is left blank, which I assume means it is lossy).
The Xbox can pass lossless from BR’s
There will never be lossless games or streaming content.
TrueHD will only exist on UHD BR... and you cannot real time encode in Dolby TrueHD.
All streaming and gaming Atmos are DD+... it is then passed either as :
The original Dolby Digital + stream, which is a lossy codec (Netflix, Amazon, Disney + etc from tv or streaming device apps..)
Dolby PCM MAT... used by AppleTV and Xbox One for example... when using those devices for streaming playback or gaming, the Atmos is decoded and system sounds/voice assistants/etc are mixed in... PCM is a lossless format, but the Dolby Atmos of the original source comes from a lossy soundtracks when using these devices.
Streaming from a home network (BR/UHD BR rips) are a separate thing...