vertical shaking

[fbs]

How can I prevent my video from shaking up/down? it's a VHS PAL-M rip... it's interlaced but I'm analyzing each field

these are consecutive frames:

one:
http://img503.imageshack.us/img503/3487/oneic3.jpg

two:
http://img503.imageshack.us/img503/6360/twoml4.jpg

three:
http://img209.imageshack.us/img209/406/threeil7.jpg

I think it would be simple for a filter to detect and stabilize it.. I tried DePan but it didn't work at all because whenever there's camera motion, it tries to move the image :(

[Tack]

I can't tell by these stills, but if the "shaking" you're talking about is by one line, this is a normal consequence of interlacing. Use a decent deinterlacer like yadif.

[IanB]

720x240 Looks like you have individual fields. 59.94 FPS as well ???

Weave() them to get full height frames again, then proceed with normal interlaced video. i.e. SmartBob/Deinterlace etc.

[fbs]

it is jumpy only sometimes.. not the whole clip.. so it's not because it's interlaced.. the second shot I posted is like 6 pixels up.. and one and three are ok.
open them side-by-side on a image editor and check it..

[foxyshadis]

Recapturing with a better tape deck would be the simplest. Alternately, you can use depan (or mvdepan) to try to correct these shifts, but it can be a bit uncontrollable sometimes.

[grannyGeek]

you could maybe try a VirtualDub filter.
DeShaker is pretty good, it's designed to combat camera shakes.
http://www.guthspot.se/video/deshaker.htm