High-speed moving picture coding using adaptively load balanced multiprocessor system

Abstract

A multiprocessor system for high-speed processing of hybrid picture coding algorithms such as H.261, MPEG or digital HDTV is presented in this study. Using a combination of a highly parallel 32-bit microprocessor, DCT and motion estimation function specific devices, a new processing module is designed for a high-performance coding system. We constructed the motion picture coder using the geometrical parallel processing technique since a single module alone cannot perform hybrid encoding algorithms at high speed, and also analyzed the processing time and communication overhead. Theoretical calculations and experimental results show that the efficiency of geometrical parallel processing system falls off as the difference of the computational amount among regions allocated to each processing module increases. An adaptive load balancing technique is proposed to resolve this performance degradation in geometrical partitioning which results from unbalanced processing time between regions. In the proposed algorithm, load estimation using DCT coefficients and load reallocation using the linear programming method are employed for optimal load balancing so that each processing module has a balanced processing time. A more balanced processing time is obtained using the adaptive load balancing technique compared to the method using only geometrical partitioning. This results in an increase of overall efficiency.