OpenMax Based MPEG4 SP Video Decoder for ARM926EJ-S Platform

Abstract

This work designed an embedded MPEG-4 simple profile video decoder with OpenMax API standard. OpenMAX API has two advantages; exploiting prominent features of the target architecture and avoiding compatibility problems. The target platform is SMDK2450 with ARM926EJ-S CPU. The decoder is first developed in C with XViD as reference, followed by plugging of OpenMAX defined modules and optimizations using ARM assembly language. Exploiting DSP features, fixed point arithmetic, lookup tables, multiple 32-bit loads, and avoiding pipeline stalls by proper ordering of instructions are among the prominent optimization techniques. At each optimization step, we measured Mega Cycles Per Second (MCPS), decoding time, frame rate and SNR. The experimental results with a VGA sized input bitstream shows a final frame rate of about 27.23 fps. Comparing to initial implementation, the frame rate is improved by about 80%.