Pre-decision strategy for coded/non-coded MBs in MPEG4

There are a limited number of MIPS (million instructions per second) available for the MPEG4 encoder on an embedded system. In these limited number of MIPS, we want to achieve the maximum possible frame rate, while maintaining the PSNR of the encoded video. There are several parts of the video encoding process that can be optimized for high quality, high compression ratio and fast encoding speed. We study motion estimation, which is the most computationally intensive part of encoding. We study a novel criterion, the mean removed MAD (MR-MAD) for block matching, which is an improvement over the mean of absolute differences, MAD. We then incorporate MR-MAD into our criterion for decision between coded/non-coded blocks and propose an efficient algorithm that performs well in terms of speed with a small cost in quality and the bit rate for different kinds of motion sequences. We have implemented these optimizations in a MPEG-4 framework and the results are encouraging.