Power and speed-efficient code transformation of multimedia algorithms for RISC processors

The upcoming multimedia processing applications will require high memory bandwidth. We estimate that a software reference implementation of an MPEG-4 video decoder typically requires 200 Mtransfers/s to memory to decode 1 CIF (352×288) video object plane (VOP) at 30 frames/s. This imposes a high penalty in terms of power but also performance. However, we also show that we can heavily improve on the memory accesses and data transfers, without sacrificing speed (even gaining about 10% on cache misses and cycles for a DEC Alpha), by aggressive code transformations. For this purpose, we have applied an extended version of our data transfer and storage exploration methodology, partly supported in the ATOMIUM environment, which was originally developed for custom hardware implementations