Hi
As things stand this plugin forces the S16N format, for reasons I'm not too sure about. There was a TODO comment, so I guess it never got looked at, although it seems quite a trivial change to me.
Anyway, I've modified it to work with any format - after all, surely it's up to the audio setup callback to reject/accept the format it has been passed?
I'm not going to make a git patch on this occasion, it's not my usual development environment so it's fiddly to create these patches and in all honesty I've yet to get any patch accepted (my fault, I'm sure!), but here is a link to the file in case it's of use to anyone. It's from the vlc-3.0 branch, but I shouldn't think it's changed much if at all for 4.0.
https://www.dropbox.com/s/79xiwgdhuvovew0/amem.c?dl=0
Cheers
Oliver