Low power memory storage and transfer organization for the MPEG-4 full pel motion estimation on a multimedia processor

Abstract

Data transfers and storage are crucial cost factors in multimedia systems. Systematic methodologies are needed to obtain dramatic reductions in terms of power, area and cycle count. Upcoming multimedia processing applications will require high memory bandwidth. In this paper, we estimate that a software reference implementation of an MPEG-4 video encoder typically requires five Gtransfers/s to main memory for a simple profile level L2. This shows a clear need for optimization and the use of intermediate memory stages. By applying our ACROPOLIS methodology, developed mainly to relieve this data access bottleneck, we have arrived at an implementation which needs a factor 65 less background accesses. In addition, we also show that we can heavily improve on the memory transfers, without sacrificing speed (even gaining about 10% on cache misses and cycles for a DEC Alpha), by aggressive source code transformations.