Every 4th frame is repeated, causing jerky playback

[gosens]

(Originally posted to TMPGenc forum but perhaps someone can suggest an Avisynth solution.)

I am encoding a DVB (satellite) source MPEG-2 file, 4:3, 29.97 fps, Progressive... it is 1970's sports film.

I use TMPGenc Plus 2.58.44.152 to encode the file using avisynth.

I have made many successful DVDs in this method, but this particular film has a problem in 10-to-20-minute chunks where a frame will be duplicated 4 frames later (ie. 1,2,3,4,1,5,6,7,8,5,9,10...) making a jerky/flickered playback. The rest of the file is fine.

I've tried setting my de-interlace filter to true, false, and removed it completely; I also tried setting TFF instead of the usual BFF; none of these worked.

The source material is ok, scanning it through dvd2avi is also fine, but through TMPGenc it is not. Scanning the frames in TMPGenc - MPEG Setting/GOP Structure/"Force picture type setting" shows the problem even before encoding.

The avisynth file I'm using is below.

Using the D2V file directly (without avisynth) showed a similar problem but in this case it was as if a half-interlaced frame was coped in 4 frames later (presumably the avisynth filter fixes the de-interlaced part by copying the rest of the frame forward, or something like that).

If anyone has any ideas about this, I'd appreciate your help.

Thanks.
gosens

Here's the avisynth filter:

movie="1975.d2v"
MPEG2Source(movie)
FieldDeinterlace(blend=false)
GripCrop(352,480)
GripSize(resizer="BicubicResize")
GripBorders()
converttoyuy2()

[stickboy]

Can you cut the MPEG2 file and post a small snippet?

[gosens]

I have to attach links for download since the 30-second clips are too large filesize.

http://lordstanley.asitechinc.com/encoded.zip
(2.5 MB)

http://lordstanley.asitechinc.com/unencoded.zip
(4.5 MB)

Linked are encoded and unencoded versions of a clip showing a "transition point" from smooth to jerky.

It appears the camera subtly fades out and comes back in as if they used different sources to piece together the film. It is always progressive, film but at the beginning of each section there are some ntsc frames.

If I begin encoding during a jerky section, it comes out smooth. It's only if I encode from before the transition point that the film turns jerky, as if it got something confused at that transition point.

thanks for any help.
gosens