HDMI eARC is required to get Dolby TrueHD/Dolby Atmos audio from Blu-ray discs. But you might be able to get Dolby Digital from Dolby-encoded discs and DTS Digital Surround audio from DTS-encoded discs.

What model Blu-ray player do you have? Do you have a PS4 Pro? What model switcher are you using? What specific Blu-ray(s) are you testing?

On the projector, make sure to set the Digital Output setting to Bitstream.

On the PS4, set Audio Format (Priority) to Bitstream (Dolby) for Dolby-encoded discs and Bitstream (DTS) for DTS-encoded discs. After you start the Blu-ray, press Option on the controller and go to Settings > Audio Format > and select Bitstream (Direct).

Hi

Yes I got the Sony UBP-X700 4K UHD Blu-ray Player Multiregion  and the PS4 PRO and a Nvidia shield Pro running through a mrocioa hdmi switch 4k

But got my projector running the ARC running down to the sonos ARC from hdmi 1 (This how i can get it to work) mrocioa switch is running up to thr projector in to hdim 2. It works with the NVIDIA SHIELD but not the PS4 or Blu-ray there are all running through the mrocioa switch,  The mrocioa a got eARC on it on Hdmi 1 but can not get it to work? Thanks for getting back to me 

Dave44

Sorry yes the movie I was testing was Mad Max 3D that as a Dolby Atmos on it

Adjust your settings to this:

Optoma CinemaX settings

Digital Output - Bitstream

PS4 settings

Audio Format (Priority) - Bitstream (Dolby)

After you start the Blu-ray, press Option on the controller and go to Settings > Audio Format and select Bitstream (Direct).

Sony UBP-X700 settings

Digital Audio Output - Auto
BD Secondary Audio - Off
Audio DRC - Off
Downmix - Surround

If these settings don’t change anything, remove the Mrocioa switch and connect the PS4 and Sony UBP-X700 directly to the projector individually to see if it makes a difference.

Ok I will give it go tomorrow morning, I'm at work at the moment  

I will keep you updated 

Thanks 

Dave44

I done the setting now I'm getting dolby digital 5.1 on PS4 and the blu ray player 

I'm very happy with this.  Still sounds amazing it's better than my Denon Avr-X2700H I think  

 Again thank you for your help 

Dave44

I done a full test now with the new settings that you gave me,  when put a blu ray dice in that's in the PS4 or the UBP-X700 I get 5.1 digital  I'm happy with that. 

the funny thing is when I put a 3D the same movie it came out stereo pcm. 

I'm going to do what you said go in to the project and see what I get. 

The movie I'm testing is mad max Fury Road 

Try changing the audio setting on the disc menu to Dolby TrueHD rather than Dolby Atmos.

I will have a look! I think it all depends on the disc if it got Dolby TrueHD, I got a lot of DTS HD 7.1 and Dolby Atmos discs. I will have to go through them and have a look and see what I got and have a play 

If you are playing a DTS-encoded disc, you need to change the settings on the PS4 to this:
 

PS4 settings

Audio Format (Priority) - Bitstream (DTS)

After you start the Blu-ray, press Option on the controller and go to Settings > Audio Format and select Bitstream (Direct)

These settings should result in seeing “DTS Digital Surround” in the Sonos app.