[Discussion] Are the spleeter models multisource or one-vs-all?

Hey thanks for making this available. Very cool project.

Lots of papers train one model per source for each MUSDB18 instrument source. Is Spleeter the same way? For instance, does `spleeter:4stems` have one model for `vocals`, one for `bass`, one for `drums`, and one for `other` (a set of OVA models)? Or are they all multisource models (i.e., one model outputs 4 source estimates)?

I looked through the code and I couldn't find any obvious either way.

Thanks again!
-e