This hasn’t been discussed in this forum for a while so I thought I’d get a discussion going in case there was any reasoning behind this, as I could not find any.
I’ve been waiting patiently for two years. The LG TV Plex app correctly sends multichannel audio from FLACs (from my music library) to my receiver but the SHIELD Plex app still sends stereo despite the SHIELD adding native support for multichannel FLAC a long time ago.
PlexforKodi on the SHIELD supports it. But it doesn’t support Watch Together and it is complicated to get Dolby Vision up and running.
I would love native support for multichannel flac from my Plex music library. It’s the only thing I’ve been waiting for. I update my Plex every week just for a taste of this but I am always disappointed.
Please add support for this. I have a large DVD-Audio collection I want to play back on my SHIELD.
I had the same issue with 5.1 FLAC’s. I got around it by creating a video in Microsoft Video Editor. I created some slides with Album Cover, Track, Artist and Album info and added them into MVE. I then put the tile time length the same as the length of the audio file and then added the next one etc till I got a video the same length as the album. I then appended the FLACS one after another in MKVToolNix and then merged the two files together. Added the chapters in MKVToolNix and it works fine. Yes it is a video with 5.1 sound but I have had great success with my Pink Floyd SACD’s (Converted to 24/96 FLAC).
Been having a think about your current 5.1 FLAC issue.
I was annoyed that there was no gapless playback with FLAC files on a lot of clients with Plex so I bought a Raspberry Pi 3B+ and DAC and made a media streamer using the free moOde software. Maybe you could do the same for to solve your problem. I think all you would need is a Pi 3A (about £20 UKP here in the UK) and use the HDMI to connect to your amp. You wouldn’t need a DAC as the amp would do all the processing for you.
Might be something to look into as a cheap stop gap (or in my case a solution to a problem that would never be solved). Once plex gets it’s act together you can use it for something else afterwards.