remember that fft3d can go temporal (in several ways too... bt=0 is my favourite but one has to be very careful with sigmas).
btw, i find that this is a good one for speed:
frfun3b(6,6,3)
degrainmedian()
i noticed a tendency toward "salt and pepper" jaggies when subsampling is increased, but following with degrainmedian will reduce those (this is more for the encoder's benefit than the viewer).
good filter - i can't wait to see the bollocks optimised out of it and a temporal mode introduced
. with motion-compensation it could be a real noise killer, but i'd only use it on really big frame sizes because it appears to eat details for lunch if abused.