field bob filter in VirtualDub

[kurczaczak]

I have bob deinterlaced 50fps video. The image is shaking vertically one pixel, so I tried using "field bob" filter. The problem is that the video isn't perfect and field order isn't always top, bottom, top, bottom and on, sometimes top/bottom field frame is after another top/bottom field frame, so the filter gets lost and sometimes introduces even more shaking, which is unacceptable.

Fortunately, my video has a few black lines in the very bottom and that value seems to be constant within whole video and different by one for bottom and top field frames, so it's easy to tell whether given frame is top or bottom.

So is there any filter that would look for top field frames and shift them by one line down?

[jagabo]

If you still have the original interlaced video go back and use a smart bob filter like QTGMC() in AviSynth.

[kurczaczak]

That's the problem - I don't.

[jagabo]

Try QTGMC(InputType=1) in AviSynth.

But after a simple bob some edges bounce up while others bounce down between frames. For example, here's a still, near horizontal line:



And after a simple Bob() in AviSynth (slowed to 2 fps for clarity):



Some parts of the line move up, other parts down, between frames. So you can't just shift a field up or down.