Variable frequency shifter and scan-line straightener

[alexh110]

Could anyone advise whether there exists an AviSynth filter that can apply a variable amount of frequency shift along each scan-line?

Ideally I would like to be able to calculate the amount of shift by tracking the central frequency of the chroma signal in the image (i.e. the avi file has been sourced from unfiltered composite PAL footage).

Also is there a filter which can straighten scan-lines that have become curved, and restore the correct line-structure?

If these don't exist, is there any C++ code anywhere which could be modified to this purpose?

[Wilbert]

Also is there a filter which can straighten scan-lines that have become curved
Could you post a screenshot of what you are trying to correct?

[alexh110]

I don't have one at the moment I'm afraid.
It does exist; I just haven't been given it yet.

[zilog jones]

Are you talking about time base correction? I've seen some VirtualDub plugins for this, but they weren't very accurate (especially when there was something black at the side of the screen).