Filter for a black border artifact in a high-contrast scene

[a11thatjas]

I am using Hybrid 2026.03.21.1 to post-process video captures from very old VHS and VHS-C home videos (20 to 30 years old). I captured the videos using a Philips VR960 VCR connected via S-Video to an I-O Data GV-USB2 coupled with AmaRecTV Ver3.10 on a Windows 11 machine. I used HuffYUV 2.1.1 to encode lossless interlaced video. I have had good success with many of the Hybrid vapoursynth filters for color, grain, artifacts and sharpening.

I have one video that has what appears to be luma/contrast artifacts in various scenes. The bright sunlight on a figure who is in front of a medium background produces a heavy black line between the brightly lit figure and the background. It is not a huge deal but if I could find a filter that would fix some of it, that would be great. I have tried nearly every vapoursynth filter. The best result I've had is from DeHalo_Alpha though it adds blur to an already blurry old video and only modestly lightens the dark line. I have attached one example screenshot with a red line around the area in question. This is after deinterlacing the video with vapoursynth though the artifact is also in the interlaced version. I have not applied any filters to the screenshot.

Thoughts on this?

   

[Selur]

DeHalo_Alpha would be the first thing I would try. (you got both bright and dark halos)
I can look at it if you can share link (i.e. mediafire, googledrive,..) a short sample of the unprocessed source. (like you would feed it to Hybrid, so not deinterlaced or otherwise filtered)

Cu Selur

Ps.: BlindDehalo restricted with some EdgeMask is another approach I would try.
PPs.: you might also want to move the dehalo filters further up the filter order.