What causes these artefacts on capture and is it possible to fix?

[raebow]

I have had some VHS tapes professionally captured and deinterlaced to 50fps.

This is not the first time I had attempted this but with a different company, and the results were unsatisfactory in most regards, however it does mean I have a file I can look at for some reference when I send tapes elsewhere to test.

Anyway I got my captures back recently and the quality seems generally good except intermittently the picture will judder up and down (they are old so ok that’s expected) but then this weird stairstep/aliasing appears over the image. The past captures from a different company were 25fps and this image problem wasn’t present on them.

Here is an example:

[Attachment 87729 - Click to enlarge]

Now it does seem to happen only when the picture judders, if the picture is stable the picture looks normal and fine.


Would appreciate thoughts. I am not sure if I should continue with them, go elsewhere or ask them to do something specific to see if it improves it.

[davexnet]

Some kind of deinterlacing artifacts. Post a sample direct from your 50 FPS captures, something showing some steady movement