Ill make this new thread, my old problem is now solved thanks to some help here and some luck I guess
New Problem is that I do not get ATMOS setting available in the Apple TV settings.
1. Samsung TV (model 2016) 75KS8005 --> HDMI Arc --> Samsung HW-N850 Soundbar. (This was with the HDMI-cable provided with the soundbar)
I have changed soundformat on TV to Bitstream and Dolby Vision
I have enabled UHD Enhanced Color Depth on the HDMI port (or whatever the name was :p)
- Apple TV 4k --> HDMI --> Soundbar
Settings is viewed like this, https://i.imgur.com/oDRPWoZ.jpg. (And I can only choose Dolby Digital 5.1 or stereo here when auto is not picked)
- PC --> HDMI --> Soundbar
When playing Dolby Atmos things from the Windows 10 app (Dolby Atmos) the soundbar shows "Dolby Atmos" So it does work here.
Any ideas why its not working from the Apple TV? Could it maybe be the HDMI-cable that is not sufficient? I did read on an apple site that you do need a HDMI cable that has this text on it "Compatible Dolby Vision". Is that correct?