Creating frames by morphing

So, say I wanted to stretch a clip to twice its normal duration, and I wanted to create additional frames to make it fit with the surrounding footage. Obviously I'd have to do it by way of morphing as opposed to interlacing. I know it involves Avisynth maybe, but... I dunno, trying to work it out just confuses me massively. Does anyone know how it works, can they step me through it?

Change the numerator/denumerator values to achieve the desired output fps.  This 60000/1001 for example will give you 59.94 fps.  25/1 will give you 25 fps, etc.    Mileage might vary.

numerator=60000

denumerator=1001

source=avisource()

super=source.MSuper()

backward_vec= MAnalyse(super,isb=true)

forward_vec= MAnalyse(super,isb= false)

interpolated= source.MFlowFps(super, backward_vec, forward_vec, num=numerator, den= denumerator, ml=100)

return(interpolated)

I... have no clue how to get that working. How do I put that in a script? I'm terribly confused.

It sounds like you should go check out the wiki page for avisynth and start from the ground up.  They have tutorials etc. for you to work with there. It was confusing to me too in the beginning.