1. A method of determining a video window displayed on a display screen, comprising: receiving a video frame formed of a plurality of pixels and including a real image within a background that is substantially synthetic; characterizing a luminance distribution of a plurality of regions of the video frame, where each region includes substantially the same number of pixels; evaluating locations of edges of the video window by identifying evaluation rectangles having a plurality of regions in which there is a transition in a luminance distribution associated with an edge between the real image and the background that is substantially synthetic; and storing edge location information corresponding to an estimate of a size and location of the video window.