PCM outputs as Stereo

[TMCsw 268]

Actually PCM is an Uncompressed digital stream of individual channels. (analog to digital conversion)

It is true that the outdated DVD's can only deliver 2 channels (stereo) and nanny devices can only handle 2 PCM channels.

Most of today’s AVR’s can receive and output/amplify these channels(5.1+) to the appropriate seekers.

For myself my fire Cube is now passing thru all DTS and Dolby types (I was sure it was previously decoding them to PCM a few months ago)

But my TCL TV will only decode them to PCM (6 channels max) but my AVR will receive this and does a decent job of (somehow) making it sound in the neighbourhood. (but I use the cube because it' better)

Of course PCM results in a high data rate and the HDMI path must support it.

But this probably doesn’t help the OP's (DTS vs. Dolby) problem,

[Tophicles 40]

8 hours ago, visproduction said:

PCM is considered to only be stereo, as far as I know.  I think you may be expecting that PCM is available in surround.

 https://www.sony.com/electronics/support/articles/00025143

 

Nope. It plays in 7.1 in other apps. Same file. Same firestick. 

[visproduction 360]

I see that PCM also seems to be listed as surround.  I have not seen that used before.  I wonder if the Firestick is just expecting to see a different audio file type before it turns surround on.  

Your Denon screen shows PCM 5.1 and output to Dolby 7.1.  Does it just create the missing 2 channels?  Maybe that setting is throwing it off and it defaults back to Stereo.

[TMCsw 268]

 

off-topic -- TL;DR

45 minutes ago, visproduction said:

Your Denon screen shows PCM 5.1 and output to Dolby 7.1.  Does it just create the missing 2 channels?

Yes it is but that is because I have set to do so (5.1 → 7.1).It is receiving a PCM 5.1 stream and using DSP to enhance it. (There was a time when DSP sucked (comb filters etc.) )

I really don’t know how it works but there must somehow be a channel ID (l,r,c,sr...) embedded in each PCM channel.

As I said I normally use my Fire Cube as it does pass-through..

The only time(s) I use the TCL is because it handles ATSC 3.0 c./w DRM and one of the channels broadcasts FHD with DV(HDR)