Here's a trick I'd like to share with you. After shooting a relatively lo-light interview, I got back to the edit suite to find noise bars and hum all over the picture. Here's what I did to minimise it, which is effectively using phase cancellation as a de-noiser. Warning - this will ONLY work with a relatively static interviewee. First, edit your interview content onto the top track of 4 video layers. Advance the mark in point on your source clip by 3 frames, then edit onto the bottom video track. Repeat for the next 2 video tracks (so we have 3 layers that are 3,6 and 9 frames ahead of our top track. Apply a 50% superimpose effect on tracks 2 + 3. Then cut a soft edge mask out for the interviewee on the top track (video 4). The varied phase relationship between the video tracks cancels out a huge percent of the picture noise - try it, it saved this interview for me!