Sorry by media info I was thinking what Kodi understood not what mediainfo the separate program reports.
Pi and vero and very different at the hardware level. I think one of the issues is that Vero currently outputs on HDMI, S/PDIF and analogue simultaneously. The sorts of signals each of those can handle are different but they all come from the same buffer. It could be that switching them on and off independently would give us greater control of the format for each.
Looking at your discussion here, Iād like to add one thought: Wouldnāt the best scenario be that signals from 2.0 up to 7.1 could be sent as they are to an AVR as to what the AVRās capabilities are. So, if an AVR can handle up to 7.1 signals, but just has 5.1 channels attached (which would apply to my usecase), the downmixing of a 7.1 signal to my real 5.1 speakers should be done by the AVR, not the Vero! ā Not: Iām sending you 5.1ā even if itās a 7.1 signal.
But the question here would be: Is the Vero 4k somehow able to detect whether the AVR can handle a maximum of 5.1 speakers or 7.1 speaker? Or is this irrelevant as (nearly) all AVRs with HDMI input can handle DTS-HD MA and DolbyTrueHD and therefore 7.1 signal processing by design (despite maybe only being able to drive 5.1 speakers) with following downmixing?
This thought of mine would also have implications for this:
Not only the downmixing of e.g. 7.1 to 5.1 or even to 2.0 should be handled by the AVR (when sending via HDMI at least), but the upmixing as well: in this example from the 5.1 signal to the 7.1 layout. But this would, of course, only be possible, if there are no blank channels sent by the Vero 4k. With blank channels an AVR cannot activate the upmixing logic as it thinks a 7.1 signal is coming in (which wouldnāt need upmixing) despite 2 of the channels carrying no audio information.
So, this would answer @Brozzieās question:
And yes, obviously, no strange noises or sounds should ever be sent by the Vero 4k on any (blank) channels at any time! This would be reffering to @grahamhās reply:
I think we are all on the same page. My remark about āeven if itās a 7.1 signalā is because I believe the hardware can only send 2 or eight channels. Maybe I should have said āeven if I seem to be sending you eight channelsā
Itās irrelevant to a point.
For example, if you only have a 5.1 setup, you should still enable DTS-HD and have the 7.1 track sent to the AV, because its post-processing will be better than any downmixing that Kodi can do.
That was basically what I wanted to sayā¦ and what I also thought to be true. 
I donāt know, if this threadās first priority is about perfect channel mapping as to not sending any blank channels in any way ever (or rather not having strange sounds and having the existing channels mapped to the correct physical speaker channels), but I had discussed this with @sam_nazarko at some point. I asked him whether the above (sending true 2.0, 3.0, 4.0, 5.1, 6.1, 7.1 channels via HDMI) could be achievable. To my understanding he wanted to look into it at some pointā¦ But Iām not sure, if it could even be done.
But as Iāve outlined (due to loss of upmixing capabilities by the AVR, also in combination with upmixing to more than 7.1 speakers: Neural:X, Dolby Upmixer, Auromatic) that it would be nice to get rid of blank channels for layouts higher than 2.0 entirely. That would be my wish and has been mentioned by others, tooā¦ Donāt know, if it could be done.
For the short-term, it would be good to stabilise the currently proposed improvements so they can be included in the next update. In other words: 2.1 and 7.1 should sound correct.
Ok, seems legit. Just wanted to bring up my wish here in the thread once as, I think, @Brozzie also mentioned this in some way before:
But obviously itās also not my top wish on the wishlist and I donāt want to push it to be a priorityā¦ 
To my understanding, the channel mapping itself should be working flawlessly with the fix by @sam_nazarko via HDMI (in contrast to what @grahamh described about the RPiās behaviour), itās ājustā about strange noises being sent every now and then AND about no sound via S/PDIF while the fix is applied at this point. Right?
Thatās probably I2S being unmuted too early before clock is set properly. Will try and reproduce some pops / clicks.
Did I miss that?
Thatās the reason, as I understood, why the fix by Sam hasnāt been implemented in the official updatesā¦ It fixes the mappping via HDMI, but breaks S/PDIF output at least for some users.
But the fix obviously isnāt perfect yet: the strange sounds some experience every now and then.
OK, thanks, Iāll check that out. Probably lose analogue as well.
Not enough to work out what the issue was completely; but Iāll send the details through on Slack.
I connected my Vero 4K and my Sony AVR with a TOSLINK cable and a direct HDMI connection to my TV (audio is always muted on TV).
With the workaround in place
Iām not sure whether this is normal behavior since the warning/hint
Nevertheless the log set of the test AC3 5.1 via S/PDIF, 7.1 speaker setting and mapping to multi LPCM:
https://paste.osmc.tv/xuvezizosa
Log set of the test AC3 5.1 via S/PDIF, 2.0 speaker setting and mapping to multi LPCM:
https://paste.osmc.tv/jowolikiju
Hmm. It looks like Kodi is telling the hardware there are only 2 channels and downmixing.
Thanks again.
Correct. You can only get 5.1 via AC3 or DTS via SPDIF.
Otherwise you get two channels, no LFE. For SPDIF, itās best to use AC3 transcoding.
Sam
So then, in summary, Iāve to say all works as designed with the workaround except
For me the thread September update breaks 5.1 Audio is extreme puzzling where a few people talk about different sound problems with no concrete data like logs and there are even users fighting with their local environment but not with an issue by the OSMC player. This thread seems to be the root cause of the general uncertainty but with current state of information it is valid to question what are real and what are phantom problems in that thread.
Splitted a separate thread Vero 4k, S/PDIF Audio, AC-3 Transcoding Flag Missing? to clarify this for the Vero 4K.
My recently purchased Vero 4k is having the problem of the original poster: AAC 5.1 audio plays as stereo, although the AVR says multi-channel PCM.
Since this thread seems to have evolved to also discuss other audio problems, should there be a separate bug report to track the progress of this specific issue? I havenāt been able to find one in the bug tracker. And it is kind of important for a media player to be able to play surround sound 
Itās being worked onā¦ The problem is known.
