video = avisource("finalrenderhuffy.avi")
v1 = video.trim(firstframe,lastframe) #first part of video that doesn't have noise
v2 = video.trim(firstframe,lastframe) #part that has noise
v3 = video.trim(firstframe,lastframe) #next part that doesn't have noise
return v1 + v2 + v3
so basically if you can't follow that, you are separating the parts that you don't want to smooth out with the ones you do... then applying only the smoothing filters to those and then adding them all together.
or you could do all your smoothing to the source itself so you don't have to do any smoothing on the final render.