insert1_torres.f4v(

The difference between and insert and an overlay is that in an overlay the video that you are putting in cuts into the other video. When you insert a clip, the clip gets longer and adds in the new clip wherever you have inserted it. The insert will most likely make the final product longer while the overlay will just cut in and wherever you put in the clip, the old stuff from the other clip will erase, or not show. Instead the new overlayed clip will show.

overlay1torres.f4v

This is an example of an overlay. You use this to put in another clip to cut into the other clip without really making in longer.