Put a name to this video glitch? What causes it?

[Hessian]

As mentioned, I'm just taking my first steps in to Analogue to DV Capture and Restoration. I started with an old VHS I had lying around that I could afford to break and I'm getting a glitch that I don't know how to describe or what causes it? Bad VCR, bad tape, bad capture?

Every few frames there's a knurling type pattern.




It's a mass produced tape from 1991, played on a Sony SLV-E700, in to a Hauppauge USB-Live2, being captured with WinTV (if any of that helps).

[jagabo]

Those are bad dot crawl artifacts. I suspect you see them mostly with high motion and only in colored areas. They are easy to filter out in static sequences.

[Hessian]

Yes it appears more so on blocks of colour.

So unless I get a VCR with S-Video out, then it's an inevitable result?

[jagabo]

Yes, you'll need a VCR with S-video out to avoid it. You can use some software filters to reduce it. Try the DotCrawl Comb filter for VirtualDub. Or DeCrawl or CheckMate in AviSynth. Can you upload a short sample?

[Hessian]

Here's a 30 second sample of the raw footage. The screenshots above were after I'd cropped and encoded it, but presumably the raw video is of more use:
https://mega.co.nz/#!R0ZRxbBR!L9iJunOwTI1rKCdwJ06GSSbKN9ITBpAfH2BSKXh_K7g

[jagabo]

Now that I've seen it in a video file, it's not dot crawl. It's some kind of herringbone noise. I don't know what's causing it. Can you try a different VCR?

You also have a terrible time base problem which is causing the frame to wiggle left/right all the time. That may be the cause of the herringbone noise too.

And finally, the video has been through an NTSC to PAL conversion with field blending. This can be mostly repaired in AviSynth with SRestore.

[Hessian]

It's some kind of herringbone noise. I don't know what's causing it. Can you try a different VCR?

I don't have access to another VCR at the moment, I am regularly checking second-hand listings and auctions sites for something suitable. The VCR has an OPC (Optimum Picture Control) would it be best to turn this off?

You also have a terrible time base problem which is causing the frame to wiggle left/right all the time. That may be the cause of the herringbone noise too.

I've ordered an AVT-8710 TBC, which will presumably help a little?

The video has been through an NTSC to PAL conversion with field blending.

I don't intend on restoring this video to any length any way so that's not a problem, it was merely a test. But that's interesting to know, I can perhaps keep an eye out for similar symptoms on other videos.

[manono]

I've ordered an AVT-8710 TBC, which will presumably help a little?

No. That has a full-frame TBC which may also be useful to you. What you need for the horizontal wiggles is a line TBC, found either in an S-VHS player with one built in, or in a pass-through device such as a DVD recorder with one. Read here to learn about the differences:

http://www.digitalfaq.com/forum/video-restore/2251-tbc-time-base.html