If you have ever heard of a "garbage matte", the Cookie Cutter compositor works the same way.

A cookie cutter is a grayscale image that defines what video source should be displayed. White represents one video source and black the other video source. If it is gray, then it is a blend of the two videos.

A cookie sutter image can be a PICT, JPEG, GIF or Photoshop image. The ideal size for the cookie is 720 X 540. An alternate size is 640 X 480, which is the same aspect ratio (4:3), but not at the full DV width (720 pixels).

Invert Image reverse the mapping of the overlay image to white and base clip to black

This tool is very versatile tool and can be used in lots of different ways. It is a simple way to create “outlines” for video within a shape. For example, a cookie image of large text and an overlay video of flames can produce text filled with fire.