A lot of the problem has to do with the microphone(s) in the video camera(assuming it's a stereo model). In my experience the microphones seem to pick up what's
BEHIND the camera more readily than they do what's in front of it! Some early Video-8 tape-based mono analogue cameras had a provision for an external microphone to be plugged in. A microphone with a good, long lead back to the camera would avoid much of the problems you're trying to remove. Why havent these newer generation of digital cameras got this feature? It would be of greater use than the manufacturers realise!
Other than this I can only suggest you go with the other ideas already expresses here. I cannot see the original post for some reason as when I look, I get a big, blue text saying "This page can't be displayed!