Separates stereo_band_mix() into the intensity and MS stereo cases
Separates stereo_band_mix() into the intensity and MS stereo cases

mumble-voip/celt-0.11.0,oneman/opus-oneman,oneman/opus-oneman,Distrotech/celt,dezelin/celt,dezelin/celt,mumble-voip/celt-0.11.0,mumble-voip/celt-0.11.0,dezelin/celt,Distrotech/celt,Distrotech/celt,oneman/opus-oneman