Neither is exactly what you want to do, but the techniques are the same. You just need to read between the lines a little bit.
Now, your video source files can help you get really close, or can get squarely in the way. It might help for you to tell us what your video source files are. Be VERY specidic, as .AVI is but a wrapper, and doesn't tell us anything.
If you have AfterEffects, it will also give you much more power, but it can be done in PrP.