Mix Audio Input and Audio from Video

Hey there,
I want to mix the sound coming from the input of an external soundcard with the audio from a video I’m playing in an oF app. I didn’t really find a way to do this. Any suggestions? Or could you recommend an external software mixer (that is ideally via OSC for example from the app)?
Ah, this needs to work on a Windows machine!

EDIT: In Audio Hijack on Mac this would look like this. Essentially I only want to control the volume slider of the input device from my app.

No ideas?