I would like to start off by saying that I have been using Libreelec for many years and very rarely have any issues whatsoever. It's a fantastic piece of software and I would like to thank everyone who contributes to the development.
My setup for the last few years was only capable of playing DD 5.1 so I was setting Kodi to output 2.0 and then selecting to re-encode everything to DD 5.1. This was fantastic and meant that I could play all of my media regardless of the sound format.
Recently, I have upgraded my soundbar to one that supports Dolby Atmos and Multi Channel PCM via eARC. It sounds SO much better and I'm really pleased with it. I changed the audio settings within Kodi to output 5.1 and selected TrueHD capable receiver but left all the DTS options disabled. This way I can get TrueHD or Dolby Atmos when available and if the source is DTS-HDMA or AAC then it outputs Multi Channel PCM. Perfect! That's exactly what I was hoping it would do.
This was working when I first set it up and tested a few different files to ensure everything played OK. Since then I have noticed a random problem. Sometimes when I play a file with DTS-HDMA or AAC 6 channel audio, Kodi will only output the FR and FL channels. There is no surround sound and crucially there is no centre channel so there is no dialogue! This doesn't happen every time - it seems to be random. I have to reboot my Intel NUC once, twice or sometimes three times before it will output the full 6 channels. When it starts working, everything is fine for the duration of that particular file. Dolby TrueHD, EAC3 and Dolby Atmos always play correctly.
I assume it's not a common problem so it may be a problem with my hardware or my particular installation of Libreelec. I don't have any additional add-ons installed, I like to keep things as simple as possible.
When I first upgraded the soundbar I was running version 12.0.2 but I have since updated to 12.2.1 but my particular issue remains.
I don't think any of my settings are wrong because when it eventually decides to work, it's perfect.
Obviously this is a little frustrating so I would be very grateful for any suggestions of what may be going wrong here.