Adjacent field blend restoration possible?

[LigH]

I have some rather old videos with a strange kind of preprocessing, apparently someone ruined the material by trying to fix deinterlacing artifacts in the wrong way.

According to my analysis, each field of these videos contains a blend of two fields of a previously progressive original content. In a Bob analysis I see a short and a large temporal jump alternating, but every field has a blend.

T0 := (T0+B0)/2
B0 := (B0+T1)/2
T1 := (T1+B1)/2
B1 := (B1+T2)/2

I do not have any experience with blend restoration filters (like SRestore), so I have to ask you, is any of them capable to improve such material?

[wonkey_monkey]

In a Bob analysis I see a short and a large temporal jump alternating

Can you post a longer sequence of Tx/Bx to understand what that means?

Or a sample...

[LigH]

I can't share it easily due to the private content.

But I measured again and came to a different conclusion. It is NTSC material, 720×480, 30000/1001 fps. But it appears to be recorded at progressive 60000/1001 fps, then blended to 30000/1001 fps instead of interlaced separately. I got confused by alternating distances of moving elements in the Bob result.

For a moment I wondered it if was once HD, scaled down to SD, but it has a 4:3 DAR and looks washed out like VHS or similar analogue magnetic tape video.

So I guess there will not be any chance to separate blends which have no repeating pattern. It was messed up and I don't really understand how. Maybe it was filmed with a "short shutter", that could be the reason why the fields are so distinct.

[johnmeyer]

It is impossible to help without a sample. This could be a scaling issue, which requires one set of tools. It could be improper resizing of material that was originally interlaced (even though your video is now progressive). If could be an NTSC to PAL conversion.

It could be ...

[LigH]

Two small snippets:

cropped (https://www.ligh.de/tmp/Crop.mp4) (all borders are multiples of at least 32)
cropped and bobbed (https://www.ligh.de/tmp/Crop_Bob.mp4)

watchable frame-by-frame in e.g. VirtualDub2.