Generalized parallelization methodology for video coding

Abstract

This paper describes a generalized parallelization methodology for mapping video coding algorithms onto a multiprocessing architecture, through systematic task decomposition, scheduling and performance analysis. It exploits data parallelism inherent in the coding process and performs task scheduling base on task data size and access locality with the aim to hide as much communication overhead as possible. Utilizing Petri-nets and task graphs for representation and analysis, the method enables parallel video frame capturing, buffering and encoding without extra communication overhead. The theoretical speedup analysis indicates that this method offers excellent communication hiding, resulting in system efficiency well above 90%. A H.261 video encoder has been implemented on a TMS320C80 system using this method, and its performance was measured. The theoretical and measured performances are similar in that the measured speedup of the H.261 is 3.67 and 3.76 on four PP for QCIF and 352×240 video, respectively. They correspond to frame rates of 30.7 frame per second (fps) and 9.25 fps, and system efficiency of 91.8% and 94% respectively. As it is, this method is particularly efficient for platforms with small number of parallel processors.