I created a "quick & dirty" tutorial for how to create slow motion from interlaced video using two instances of Vegas, Debugmode's Frameserver, AVISynth, VFAPIConv, and a slow motion script that uses a free motion estimation plug-in called MVTools2.
It may sound complicated, but the tutorial is only three minutes long, and it takes a lot less time than that to actually create the video once the various free tools have been downloaded and installed.

Here's one of two scripts that I use for interlaced video slow motion:
I have other scripts that operate quite a bit faster, but this one is likely to have the fewest problems.
It may sound complicated, but the tutorial is only three minutes long, and it takes a lot less time than that to actually create the video once the various free tools have been downloaded and installed.

Here's one of two scripts that I use for interlaced video slow motion:
loadplugin("C:\Program Files\AviSynth 2.5\plugins\MVTools\mvtools2.dll")
source=AVISource("E:\frameserver.avi").KillAudio().assumetff()
final=ApplyInterlacedFilter(source,"SlowMo").assumefps(29.97,false)
return final
function ApplyInterlacedFilter(clip v1, string filter)
{
v2 = separatefields(v1)
selecteven(v2)
even = Eval(filter)
selectodd(v2)
odd = Eval(filter)
interleave(even,odd)
return weave()
}
function SlowMo(clip thisclip)
{
super = MSuper(thisclip,pel=2)
backward_vectors = MAnalyse(super,blksize=8, overlap=2, isb = true, search=3)
forward_vectors = MAnalyse(super,blksize=8, overlap=2, isb = false, search=3)
# num=60000 produces 50% slow motion; 120000 produces 25% slow motion, etc.
MFlowFps(thisclip,super,backward_vectors, forward_vectors, num=60000, den=1001, ml=100)
}
I have other scripts that operate quite a bit faster, but this one is likely to have the fewest problems.