function step7slow(clip base, bool "preview", int "in", int "out",
	\ int "initspd", int "transpda", int "transpdb", int "slowspd",
	\ int "buffa", int "buffb", int "thresh", bool "debug") {
	prv = default(preview, false)
	dbg = default(debug, false)
	in =  default(in,  0)
	out = default(out, 0)
	initspd  = default(initspd, 1)
	transpda = default(transpda, 2)
	transpdb = default(transpdb, 3)
	slowspd  = default(slowspd, 4)
	inc1 =      round(default(buffa, 6))
	inc2 = inc1+round(default(buffb, 6))
	thresh = default(thresh, 0)
	
	clipa =         changespeed(base, 0,        in,       initspd,  thresh, prv, dbg)
	clipb = nofirst(changespeed(base, in,       in+inc1,  transpda, thresh, prv, dbg))
	clipc = nofirst(changespeed(base, in+inc1,  in+inc2,  transpdb, thresh, prv, dbg))
	clipd = nofirst(changespeed(base, in+inc2,  out-inc2, slowspd,  thresh, prv, dbg))
	clipe = nofirst(changespeed(base, out-inc2, out-inc1, transpdb, thresh, prv, dbg))
	clipf = nofirst(changespeed(base, out-inc1, out,      transpda, thresh, prv, dbg))
	clipg = nofirst(changespeed(base, out,      0,        initspd,  thresh, prv, dbg))
	return clipa+clipb+clipc+clipd+clipe+clipf+clipg
}

function nofirst(clip base) {
	return trim(base, 1, 0)
}

function changespeed(clip base, int in, int out, int factor, int thresh, bool prv, bool debug)
{
	in = in*factor
	out = out*factor
	frate = round(base.framerate)

	base = prv?Bob(base) : LeakKernelBob(base, 0, threshold=thresh)
	base = assumefps(base, frate)
	# compensate for bob doubling
	factoradj = factor/2.0
	
	# speed label currently tied to previewing
	base = debug ? base.subtitle(string(factor)+"x SlowMo") : base
		
	backward_vec  = prv?nop(): base.MVAnalyse(isb = true, truemotion=true, pel=2, idx=1)
	forward_vec   = prv?nop(): base.MVAnalyse(isb = false, truemotion=true, pel=2, idx=1)
	cropped       = prv?nop(): base.crop(4,4,-4,-4)
	backward_vec2 = prv?nop(): cropped.MVAnalyse(isb = true, truemotion=true, pel=2, idx=2)
	forward_vec2  = prv?nop(): cropped.MVAnalyse(isb = false, truemotion=true, pel=2, idx=2)

	newfps = round(frate*factoradj)
	base = prv? changefps(base, newfps) : MVFlowFps2(base, backward_vec,forward_vec,backward_vec2,forward_vec2,num=newfps,idx=1,idx2=2)
	base = assumefps(base, frate)

	base = trim(base, in, out)
	
	return base
}