@Stax76 wanted to post an update on the FFMPEG demux to core. It does not work correctly, it results in an error dropping from 7.1 to 5.1 core.
Here is a logfile.
https://pastebin.com/C9rXVgzP
https://i.imgur.com/W7HywQ1.png
These are the settings that I used. The source was a 7.1, that FFMPEG command will automatically reduce a DTS 7.1 (of any variant) and a DTS 5.1 (of any variant) to DTS 5.1. If the source is a DTS 2.0 of any kind, it will reduce to core but keep the same channels.
I don't know but the channel/sample rate selection should be greyed out if it's effecting the command. I don't know if it is, however, I tried the command by setting the channel to original and 5.1 and both threw an error.
This is running the command manually
https://pastebin.com/XShARNGX
I think it's due to the fact that StaxRip is outputting to a .wav file. I don't know if that's required at all what so ever.
Either way, let me know if you need any more information. Thanks as usual!