Check if porting is correct : ChubbyRain for VapourSynth

[bebs]

Here is my port from ChubbyRain (http://avisynth.nl/index.php/ChubbyRain)

Original code :
# http://avisynth.nl/index.php/ChubbyRain

function ChubbyRain(clip c, int "th", int "radius", bool "show", bool "interlaced")
{

th = default(th,10)
radius = default(radius,3)
show = default(show,false)
interlaced = default(interlaced, false)

c = interlaced==true? c.separatefields() : c

u = c.utoy()
v = c.vtoy()

uc = u.mt_convolution(horizontal="1",vertical="1 -2 1",Y=3,U=0,V=0)
vc = v.mt_convolution(horizontal="1",vertical="1 -2 1",Y=3,U=0,V=0)

cc = c.mt_convolution(horizontal="1",vertical="1 2 1",Y=2,U=3,V=3).temporalsoften(radius,0,255,2,2)

rainbow = mt_lutxy(uc,vc,Yexpr=string("x y + "+string(th)+" > 256 0 ?")).pointresize(c.width,c.height).mt_expand(y=3,u=-128,v=-128)

overlay(c,cc,mask=rainbow)

output = show==true? rainbow : interlaced==true? last.weave() : last

return output

}


My port :
def ChubbyRain(clip, th = 10, radius = 3 , show= False, interlaced = False, tff = True):
core = vs.get_core()
if interlaced is True:
res = core.std.SeparateFields(clip=clip, tff=tff)
else:
res = clip

y = core.std.ShufflePlanes(res, planes=0, colorfamily=vs.GRAY)
u = core.std.ShufflePlanes(res, planes=1, colorfamily=vs.GRAY)
v = core.std.ShufflePlanes(res, planes=2, colorfamily=vs.GRAY)

uc = core.std.Convolution(u, [1,-2,1], mode = "v")
vc = core.std.Convolution(v, [1,-2,1], mode = "v")


ucc = core.std.Convolution(u, [1,2,1], planes=0, mode = "v")
vcc = core.std.Convolution(v, [1,2,1], planes=0, mode = "v")

cc = core.std.ShufflePlanes([y,ucc,vcc], planes=[0, 0, 0], colorfamily=vs.YUV)
cc = core.focus.TemporalSoften(cc, radius=radius,luma_threshold=0, chroma_threshold=255 ,scenechange=2 , mode=2)

expr = "x y + " + str(th) + " > 256 0 ?"

rainbow = core.std.Expr([uc,vc],expr)
rainbow = core.resize.Point(rainbow, res.width, res.height)
rainbow = core.generic.Maximum(rainbow)

resfinal = core.std.MaskedMerge(res, cc, rainbow)
#resfinal = Overlay(clipa=res, clipb=cc, mask=rainbow)

if show is True:
output = rainbow
else:
if interlaced is True:
output = core.std.DoubleWeave(resfinal,tff=tff)
output = core.std.SelectEvery(output, 2, 0)
else:
output = resfinal

return output


Is this correct ?
Some rainbow are not catch but i don't understand why