I'm in need of help guys.
I'm making a music video at the moment and I want to make an effect where there will be disturbing white lines like electricty showing up in the middle of the screen every now and then.
But that's not it...Also, when the electricity starts showing up, I want the lines that are crossing the screen to take the footage with them, moving the footage left and right in the spot where the lines show up.
It's really difficult to explain but I can't find an example of the effect I want to make anywhere but kind of like a surveilance camera when it gets disturbed by something.
as far as making things random, you'll want to search around for random and wiggle expressions. you should be able to use those in both position and opacity (maybe scale too) to create random lines.
here's a page from motionscript.com that has an expression for looping random moving lines (note, you may want to read some of the preceeding pages, too).
if you precomp the white lines, you can use them as a displacement map (in the effect of the same name) on the footage layer to distort the footage.
you might also check out twitch from videocopilot.net. it seems like it will do what you are looking for in one effect, without needing to use expressions. andrew has a few tutorials that demonstrate it too.