[HELP] Alternating scanline horizontal shift / diagonal striping on VHS dub

[Finnish_Digitize_Assoc]

   
I'm struggling with a nasty artifact on transfer that I haven't been able to fix cleanly in Hybrid, and I've attached a short 2-second raw cut from the original capture.

• Format: PAL 576i, Interlaced TFF, ProRes 422
  

The tape is a generation copy: the customer originally dubbed camcorder footage (most likely Hi8, possibly VHS-C) onto a VHS tape. This is the only cassette in the entire customer batch with this problem, so the artifact was definitely baked in during that original analog dubbing.

Across the entire frame, every other scanline is shifted horizontally left or right, creating a prominent diagonal striping / herringbone pattern over the whole picture. QTGMC does its job properly removing the VHS tape's own interlacing in motion, but this diagonal striping originating from the previous tape remains fully in the video. I've already tested QTGMC in TFF, BFF, and mixed modes.

I also tried using the decrawl tools in Hybrid, but couldn't get them to touch this pattern and wasn't sure how to configure them for it. Neat Video only removes it if pushed so hard that it turns the entire video into mush. I even spent days testing different models and settings in Topaz Video AI, but it just turns faces into waxy zombies.

Is there any AviSynth or VapourSynth filter in Hybrid that can target and realign or filter out this baked-in alternating scanline shift without destroying the rest of the image?

Best Regards
Finnish Digitization Association

[Selur]

Busy today and probably tomorrow, but what you can try for the diagonal lines:

• Enable Frame->Resize->Resizer->NNEDI3
  
• Enable Frame->Resize->Lower resolution before resize with 'bicubic', '2' and only 'height'
  
• Enable DeNoise->QTGMC->Input Type 3
  
• Move QTGMC in the FilterOrder behind the resize
  

Will think about it some more over the weekend.

Cu Selur

Ps.: https://forum.videohelp.com/threads/3726...onal-lines. https://forum.videohelp.com/threads/3987...ne-removal might be interessting

[Finnish_Digitize_Assoc]

Quick update on the clip. When I originally tried to resize the height to 288 directly in ''Lower resolution before resize'', the entire video rendered bright green.
Probably the GUI resize broke chroma subsampling etc.

To bypass that, I unchecked resize in the GUI completely and put this directly into Filtering -> VapourSynth -> Custom:
clip = core.resize.Bilinear(clip, width=720, height=288)
clip = core.resize.Bilinear(clip, width=720, height=576)

DeNoise -> QTGMC

• Preset: Slower
  
• Input type: 3
  
• Sharpness: 0.0
  
• Final temporal smoothing: 2
  

This gave the best result so far: the baked-in comb lines are completely gone, with the only tradeoff being that the image gets slightly softer vertically because of the downscale.

picture of the result:
   

[Selur]

Green: Doesn't happen here, so it's probably one of the small bugs I fixed in a dev version.
About the smoothing, try using chaning the settings in NNEDI3 and may be sharpen in QTGMC.

Cu Selur