When you export from ddo you choose a Calibration profile to export with. Awhile back I noticed that the profile is backed by script that has instructions with how to pack the output files. If the frostbite engine team was willing to share how they packed things I would guess that making calibration profile would probably…
That B channel doesn't look like a metallic mask to me. Frostbite takes as input base color, metallic, AO, and a specular tweak map that can suppress Fresnel reflections below .25 linear and maps to semiconductor base reflectivity above .8 linear or so. To me it looks like R for the specular texture is metallic, G is the…