Tearing: is fixing it a lost cause?
 

I'm trying to salvage a video from 35 years ago, but it has some major tearing/flagging/whatever you want to call it at the top for the first few minutes before it mostly settles down into more of a minor strip along the top. I should mention this video is a dub, so that may be part of the issue right there; maybe even the WHOLE issue. I'm thinking this might be less a defect with the current tape than it is an accurate recording of what it was being fed decades ago, because the things recorded before and after it (regular broadcast recordings) aren't skewed at all.

I'm thinking there's no fixing it during capture. I've tried it in two regular vhs decks and two svhs decks, and this is about the best I could get. Adjusting the tracking had no effect, other than making everything worse. Playing with the JVC settings (calibration, stabilizer, etc) had no real effect.

I'm probably looking at something crazy like having to manually tweak individual still frames in Photoshop to truly fix it, which I don't care enough to do, but I thought I'd ask in case there was some (relatively) simple fix or filter or something! :)

Since it isn't a first generation tape (you mention that it is a dub), it might not be possible to totally correct, but my guess is that a DMR-ES10 in passthrough mode will help some or possibly fix it completely if used as a passthrough device. The only way to really correct that appropriately would be at the time of capture, so I wouldn't capture a bunch of tapes that way and expect to be able to fix it later with filters.

The other question would be if any of the VCRs you're using have a line TBC present and turned on? That alone can often resolve the issue without needing to use an ES10.

There's a good thread here on the actual settings you'd want to use on the ES10. You do need a remote to change some of those settings I believe:
https://forum.videohelp.com/threads/...15-DMR-ES25%29

One of the vcrs is a JVC HR S7800U, so it has a TBC, which certainly helps, but it might be overmatched. I was looking at getting an ES10, even ordered a remote for it, but ended up getting the JVC instead. At least if I ever do get the ES10, I'll have a remote ready! :P