this was c&p
Hey all, so I recently got a Dolby Atmos sound bar (with eARC!) and attempted to play one of the Atmos trailers with VLC on my HTPC, and was surprised to find that the sound bar was not receiving the Atmos information. I knew that Atmos content worked, because when I played the same file with the built-in Windows TV & Film app I saw the word "ATMOS" flash by on my sound bar (its a HW-Q90R for reference). So of course I went to Google to try and figure out what the issue was, but was surprised to see there wasn't a solution readily available; most people recommended using a different media player (not an option for me, I love VLC) or enabling HDMI pass through, but this wasn't enough for me (and most other people) to get Atmos working. Luckily I was able to get it working in VLC 3.0.8, so I figured I would post my solution here for other people googling for a solution like myself. Here are the settings you need to change:

Go to Preferences > All > Audio > Output modules

Change "Audio output module" to "Windows Multimedia Device output"

Go to the "MMDevice" settings

Change the "Output back-end" to "Windows Audio Session API output"

Set "HDMI/SPDIF audio passthrough" to "Enabled"

You should be all set! Remember you need to download the Atmos app from the Windows Store first.

Hope this help ones that play atmos