VHS horizontal bounce

[rds11]

My local NBC , back in 1994, sometimes would have the picture switching a few pixels left or right, and then coming back to its place a few frames later. This is not a VCR issue, nor TBC, has I've tried a number of different VCRs, and a number of TBC, and all the captures have the exact same issues at exactly the same frames. Moreover, other recordings I did at the same time, but on other networks, are fine.

I've tried a number of stabilization scripts in avisynth without success. Right now, my solution is to look at the video, find when the ''bounces'' occur, find which fields need to be moved back into place and use something like ClipClop to replace each field, one by one, with the same one but with a cut / addborders done in order to correctly align with the rest of the video.

I've attached a example. Anyone has any idea how to stabilize the video ? Or at the very least, identify which frames do not have the same black margins to the Left and right as the other frames ?

[Selur]

Maybe I'm missing the problem.
I don't see it, seems to work fine with:

AssumeTFF()
QTGMC()

(used BestSource as source filter)

Cu Selur

[Alwyn]

Selur, could you please encode using H264 or other common codec. VDub2.0 won't open AV1.

Using my main NLE to open that AV1, the effect/bounce is obvious: frame 14>15 of your MP4. Watch the subtitle move right.

[Selur]

Ah, do you mean the shift between index 37 and 38?
Looks like parts of the image got compressed/stretched, like parts were lost during transmission and got compensated by the decoder.
Here's what happens if you:
a. separate the clip into fields
b. apply Stab
c. re-interlace it
d. de-interlace it
e. crop
that seems to lessen the effect a bit.
To get rid of such frames, you probably will have to replace them with interpolated frames.

Cu Selur

Ps.: Looking at the fields, separated and stacked vertically makes it easier to see the problem.

[rds11]

To illustrate the issue, in the attachment, the frame moves about 2 pixels to the right on frame 19, then goes back starting at frame 62. Moves again o the right at frame 811 and goes back at frame 898. Moves again at frame 1056 and goes back into place at frame 1074.