One embodiment of the present invention provides an apparatus that facilitates compression of video data in a computer system by performing the time-consuming task of computing the difference between successive frames of video data. Thus, one embodiment of the present invention can be characterized as an apparatus for compressing video data. This apparatus includes a video input port, for receiving video data for a current video frame, and a video input buffer, for storing video data from the video input port. The apparatus additionally includes a previous frame buffer, for storing at least a portion of a previous video frame, as well as an operation unit, for performing an operation between video data from the video input buffer and video data from the previous frame buffer. The embodiment also includes a result buffer coupled to the operation unit, for storing the result of an operation from the operation unit.