Video processing engine overlay filter scaler

The present invention is directed to an Video Processing Engine that is an Overlay Filter Scaler (OFS) having a memory to memory video signal processor decoupled from the display that is better able to meet the feature requirements of a computer graphics system while simplifying the design. The memory-to-memory operation of the video signal processor also facilitates the display of more than one video stream by allowing processed images to be placed in the primary graphics buffers for display. This is particularly useful in video conferencing applications, and for displaying multiple live "thumbnails" of various video feeds. In addition, the signal processor can be used as a graphics anti-aliasing filter by having it process 2-D and 3-D computer graphics images before they are written to the primary display buffer. Similarly, the signal processor can also be used as a "stretch-blitter", to expand or contract graphics as needed.