Yamaha receiver always shows PCM with audio passthrough

[napper1237]

Hi all

I've had a couple of other threads on the go regarding related elements of my setup (all new to me).

QNAP TS-451
Android Box (Himedia H8 Octacore)
Yamaha RX-V583 receiver
5.1.2 Speakers
Optoma Projector

The QNAP sits merrily on my network and everything's CAT6.
The Himedia is also on the network and into the receiver with HDMI 2.0.

On the box - KODI 17 Krypton, Plex, SPMC as options.

My question is this:
With any of the above three media apps whether using audio passthrough or local decoding, the Yamaha always shows the input signal as being PCM 2/0/---, 44.1 kHz sample rate.

The receiver can be set to Straight (apparently playing source as it comes) or DSurround (Surround decoder). With Straight the amp is only ever displaying front L R and SW, with DSurr all 8 channels light up (input signal still reads PCM 2/0/---) .

Does anyone know these Yamaha receivers and know whether this is correct please? Am I actually getting the ATMOS channels in either of these two modes?
secondly if I let the Android box do the work will the amp receive all 8 channels and output them correctly? If so which mode. (I suspect 'Straight' for this one and DSurround for the passthrough but not sure).

I have read many threads regarding the display of PCM and so far am being told that it's correct but having spent the cash on the upfirers I want to know it's working as it should (to be honest I'm not blown away like some people appear to be by the Dolby theater demos)

Thanks

[napper1237]

Update....confirmed that the Yam DSurround setting is merely an upmix to 7.1. Sooo...the receiver is only getting PCM 2...