Method and apparatus for overlaying two video signals using an input-lock

摘要: Disclosed is a method and apparatus for combining first second video signals to produce composite signal display. First sources generate signals. A chroma key circuit included comparing each pixel of the with preselected color generating logic indicating whether or not matches color. An input lock map stores when field data in state provides on an output line thereof state. frame buffer selectively receives (1) complement (2) The operative store which comprised plurality selected pixels from have corresponding that indicate they do match correspond locations matched