VHS tape top/bottom borders shift up/down?

[rubiks-dude]

I have a dilemma, I'm currently restoring a VHS tape that has borders on the top and bottom that shift up and down throughout the video by as much as 15px in either direction. It happens about every frame, although not necessarily to that extent every time, and there are 37k frames in total. So manually going through each frame to account for every difference is not a viable option. The options as I see it are:

1. One-size crop it all away and lose part of the picture in the process.

2. Crop part of it away, keeping the borders, but only about a third or fourth of what they were before.

3. Crop none of it, keep the borders.

Looking for some advice on which solution would be preferable in this situation, or if there's another option.

I should mention, the actual picture does not jiggle up and down, just the borders. So it's not a TBC issue or anything, it's just a flaw of the video itself that the borders aren't stable.

[traal]

For viewing on a CRT: #3, because the borders were probably hidden behind the TV's bezel anyway.

For digital viewing: #1, assuming the changing borders are distracting.

If the picture is mostly static, with the camera mounted on a tripod, you could paste borders from good frames onto bad ones to avoid losing resolution while minimizing distracting artifacts.

Some sort of AI fill might work well here.

[Selur]

share a short sample if you want suggestions

[lordsmurf]

Sample needed.

[Aya_Rei]

As others have said, a sample is needed. Strange how it only affects the borders, and I'm assuming the head switching noise on the bottom too.

I've come across a video8 tape where the head switching noise and top of frame do quickly move up and down, but that only happened during a part of the tape that was extremely shaky. As in, the footage was of the cameraman rushing through the woods at fast speed. The internal TBC of the camcorder didn't help to fully keep that section of the footage steady, it was just that shaky.

[latreche34]

Unless the captured file has undergone some kind of de-shaking filter to eliminate the hand shaking of the camcorder that usually adds black space when the frame is out of the safe area I don't see how this happens on a normal tape capture.

[Hushpower]

Quote:

So manually going through each frame to account for every difference is not a viable option.

If I'm reading the issue correctly, that would never work because you'd have black edging coming and going.

You can either crop 15px off the top and bottom to remove the jumpy stuff (with requisite side cropping to maintain the display ratio) or cover the top and bottom jumpy edges with black borders and keep the same frame size. Borders would look OK if applied to the whole of the jumpy portion.

[rubiks-dude]

Quote:

Originally Posted by Selur

share a short sample if you want suggestions

Quote:

Originally Posted by lordsmurf

Sample needed.

Quote:

Originally Posted by Aya_Rei

As others have said, a sample is needed.

Quote:

Originally Posted by latreche34

Unless the captured file has undergone some kind of de-shaking filter to eliminate the hand shaking of the camcorder that usually adds black space when the frame is out of the safe area I don't see how this happens on a normal tape capture.

Quote:

Originally Posted by Hushpower

If I'm reading the issue correctly, that would never work because you'd have black edging coming and going.

Uploaded an example. I spliced together two scenes from the unfiltered capture to showcase how much it can be off by.

[Hushpower]

Thanks for the sample. I see what you mean. That's a bummer, because the borders are actually burnt into the image with the video part changes vertical position. The first scene the light part) looks to be about 6 pixels taller overall than the second purple scene, and the end of the purple scene looks like it is a couple of pixels less-tall than the first part. A nightmare!

I see a few options:
1/ Crop each scene individually so that you have only the active picture, no bars, then resave it. If there are many scene changes, that will become tedious, and I'd only do it in a video editor. This will retain as much of the active video as possible. Example Vid 1 attached.

2/ Apply a simple crop across the whole video with VDub; you'll lose the top few pixels and bottom pixels depending on which scene you're looking at. Example Vid 2 attached. You won't notice what's missing when you play it. Can you tell the difference between 1 and 2?

2A/You can add black borders back in if you wish (VDub). Attached Vid 3. Not the bets option though because the actual video part is longer than 4:3 and so fills more of the screen without the top and bottom borders.

Examples 1 and 2 are non-standard frames size; I'm not sure what the original is supposed to be but these play correctly in VLC, my Android and TV.

[rubiks-dude]

Quote:

Originally Posted by Hushpower

Thanks for the sample. I see what you mean. That's a bummer, because the borders are actually burnt into the image with the video part changes vertical position. The first scene the light part) looks to be about 6 pixels taller overall than the second purple scene, and the end of the purple scene looks like it is a couple of pixels less-tall than the first part. A nightmare!

I see a few options:
1/ Crop each scene individually so that you have only the active picture, no bars, then resave it. If there are many scene changes, that will become tedious, and I'd only do it in a video editor. This will retain as much of the active video as possible. Example Vid 1 attached.

2/ Apply a simple crop across the whole video with VDub; you'll lose the top few pixels and bottom pixels depending on which scene you're looking at. Example Vid 2 attached. You won't notice what's missing when you play it. Can you tell the difference between 1 and 2?

2A/You can add black borders back in if you wish (VDub). Attached Vid 3. Not the bets option though because the actual video part is longer than 4:3 and so fills more of the screen without the top and bottom borders.

Examples 1 and 2 are non-standard frames size; I'm not sure what the original is supposed to be but these play correctly in VLC, my Android and TV.

Thanks for taking the time out to look and provide those examples. The og capture was 720x480 with 8px left/right borders cropped out to make it 704x480.

Yeah #1 would probably be too tedious, it's about the length of a standard anime episode (25ish minutes) with quite a few scene changes. Between #1 and #2, I'm leaning more towards the latter because definitely while viewing the video, it's not as apparent how much is getting cropped off. My only hold up is that I know how much is getting cropped off.

Using method #2, I included pictures (CropResizePic1,2,3) of how many pixels would get cut using CropResize. In some scenes, character faces even end up getting cut off. Just spitballing, but a solution that's a combination of #1 and #2 may be necessary. A general, less extreme one-size crop with manual adjustments for scenes that get cropped too much or too little. The problem with that method is maintaining the correct aspect ratio and pillarboxing between scenes. If certain scenes require different amounts of cropping, I'll end up with wonky borders.

Regarding method #2a, yeah I'd probably not use that method. If I were to do that, I'd probably just leave the borders as they are in the video.

On the one hand, I want to find a good solution for this, but on the other, a part of me wants to say screw it and either one-size crop all of it, or crop none of it and just keep it as is.

[traal]

It appears to be a letterboxed video, and the picture position within the 4:3 frame only changes occasionally, not every frame. And if the sample is any indication, it doesn't change by much.

Try cropping the minimal amount from the top and bottom that never cuts off any of the picture.