Random "jitter" using QTGMC / Avisynth+

[lv2race]

I recently built a new PC and installed Avisynth+ 64 bit and put all the associated filters in the Plugins64+ folder. The computer is running Windows 11.
Previously, on an older PC, I was using Avisynth 32 bit and Windows 7. On the old PC I did many VHS conversions without any issues using a Panasonic AG-1980. For the new PC I just tried out a JVC SR-V10U.

My current workflow for the new VHS conversions from a ~ 1989 RCA Camcorder using VHS tapes is: JVC SR-100 > DataVideo TBC-1000 > ATI AIW on PC running XP > Avisynth on PC running Windows 11.

The changes from my original successful workstream are going from a Panasonic to JVC VCR, AviSynth 32 bit to AviSynth+ 64 bit, and Windows 7 to Windows 11.

The problem I have is when running QTGMC the video randomly has what I'm calling "jitter", meaning it will go in reverse one frame and then move forward. The captured video plays back smoothly. For troubleshooting I took an old Panasonic capture and ran it through Avisynth+ and the jitter doesn't exist, leaning me towards a problem with the JVC VCR. I tried multiple captures with the JVC, with TBC on/off, video calibration on/off, etc., and they all exhibit this problem. I've also installed all the latest filters as near as I can tell.

My Avisynth+ script:

ffmpegsource2("B:\clip.avi")
ConvertToYV12(interlaced=true)
AssumeTFF()
QTGMC("Fast")

Attached is the original capture clip, and the clip with QTGMC where the problem occurs.

Any thoughts?

[poisondeathray]

The captured video plays back smoothly.

It does not

The problem is your source. Nothing to do with QTGMC

If you AssumeTFF() with Bob() or SeparateFields() and advance you can see the problem in clip.avi

[lv2race]

Understood, thanks. Confirms it's the VCR. Appreciate the quick feedback.