question on slow motion using mvtools

[mgh]

I used the following function to get slow motion

Function slowdown( clip clip, int c ) {
# c is the slowdown factor
fn=FramerateNumerator (clip)
fd=FramerateDenominator(clip)
b=fd*c
source=assumefps(clip,fn,b).killaudio()
backward_vec = source.MVAnalyse(isb = true, truemotion=true, pel=2, idx=1)
forward_vec = source.MVAnalyse(isb = false, truemotion=true, pel=2, idx=1)
cropped = source.crop(4,4,-4,-4) # by half of block size 8
backward_vec2 = cropped.MVAnalyse(isb = true, truemotion=true, pel=2, idx=2)
forward_vec2 = cropped.MVAnalyse(isb = false, truemotion=true, pel=2, idx=2)
return source.MVFlowFps2(backward_vec,forward_vec,backward_vec2,forward_vec2,num=fn,den=fd,idx=1,idx2=2)
}

To my surprise, I found that the script also did excellent denoising.
Could one get temporal denoising without blending of frames by using above function as follows?

slowdown(2)
selectodd()
assumefps(original fps)

[foxyshadis]

Look just a little further and you'll find MVDegrain1 & 2, which take care of all the particulars for you. ;)

[mgh]

Have been using mvdegrain2 for some time now. My tests had shown approx.10 to 15 % improvement in compressibility with mvdegrain1 and approx. 25 % with mvdegrain2.

I made an addition to my earlier script as follows

Function cleanmv( clip clip, int c ) {
fn=FramerateNumerator (clip)
fd=FramerateDenominator(clip)
b=fd*c
d=c/2
d=int(d)
source=assumefps(clip,fn,b).killaudio()
backward_vec = source.MVAnalyse(isb = true, truemotion=true, pel=2, idx=1)
forward_vec = source.MVAnalyse(isb = false, truemotion=true, pel=2, idx=1)
cropped = source.crop(4,4,-4,-4) # by half of block size 8
backward_vec2 = cropped.MVAnalyse(isb = true, truemotion=true, pel=2, idx=2)
forward_vec2 = cropped.MVAnalyse(isb = false, truemotion=true, pel=2, idx=2)
vid=source.MVFlowFps2(backward_vec,forward_vec,backward_vec2,forward_vec2,num=fn,den=fd,idx=1,idx2=2)
vid=selectevery(vid,c,d)
vid=assumefps(vid,fn,fd)
return vid
}

Tried the function with values of the parameter from 2 to 10. Still to check compressibility, but it seems to be better at removing artefacts such as grainy edges than mvdegrain 1 &2 and much faster.