How do I convert 60fps progressive to 29.96fps interlaced?

[Supremus]

I am trying to convert a 60fps 720x480 Flash animation to a 29.97fps 720x480 interlaced MPEG2 video. So far I have come up with the following AVIsynth script, but it doesn't quite do the job...

AssumeFrameBased
SeparateFields
SelectEvery(2,0)
Weave()

The animation does end up as 30 fps interlaced, but the fields are a bit buggered. It looks like I would need to shift one of the fields/frames up a line, as everything has gone sort of double-pixel, probably due to the fact that weave used the same vertical lines for each interlaced field.

So it looks like my script is a bit incomplete. Does anybody have any suggestions, or perhaps even a guide on how to do this? I tried searching for something on the subject, but I couldn't seem to find anything.

[bugster]

Can't help with your avisynth script, but why not convert it to 29.976fps progressive?

[Supremus]

I need the extra smooth motion of interlaced.