Is there a way to get posterized look - basically a reduced number of colours I think. I can't find such a filter in the VideoFX set but thought maybe there's a way to achieve that look...
David
You can do this with color curves to some degree. Add several points and use the curve handles to make a "stairstep" curve. If you can get the line segments to be as close to horizontal & vertical as possible you'll end up with posterization. The fewer steps you have the fewer colors will be in the output.
You can get some weirder looks by separating the curves into separate red/green/blue lines and making different steps for each.
...to skin this cat. VDub has some filters that do things similar to what you're asking -- look at virtualdub.org and use satish's frameserver plugin. Pixelan's stuff might be able to help you in this regard, as well.