I have a 29.97 fps AVI which has a five frame pattern - 3 progressive frames followed by 2 progressive (but blurry in the motion parts) frames.

From all I have read, I assume that this video started as FILM, was telecined to 29.97, and then was deinterlaced.

Since I want to convert to SVCD, I would sure like to get it back to 23.976 so I can have more bitrate per frame. But, since it has been deinterlaced, that makes it harder to IVTC, right? Reconstructing a single blurry frame from the 2 blurry frames would be something, but what is the best way to do that? (I am familiar with frameserving from VDub, and with using AVISynth scripts, if someone could just suggest an ideal filter)

I am wondering, though, if the blurriness (deinterlacing) I see is, in fact, the result of post-processing by the video codec. If this were the case, then if I could only access the un-messed-with frames, I could do a proper IVTC and get perfect progressive frames back, right? I know that MPEG-2 codecs will usually deinterlace, but I do not know about MPEG-1 or AVI codecs. The video in this case is using the DIVX PRO 5.02 codec. Thanks for any advice.