Q&A is for both v2.0x and v2.5x, but not everything was updated when v2.5 came
I don't use spatialsmoother and spatial soften so I can't comment on that. For analog capture I use (only included the smoothing):
convolution3d(preset="vhsBQ")
or with two captures from different broadcastings:
clip1=avisource(1.avi)
clip2=avisource(2.avi)
Layer(clip1,clip2,"fast").convolution3d(preset="movieHQ")