FPGA-based msb-first bit-serial variable block size motion estimation processor

H.264/AVC is the latest video coding standard adopting variable block size, quarter-pixel accuracy, motion vector prediction and multi-reference frames for motion estimation. These new features result in much higher computation requirements than previous coding standards. In this paper we propose a novel most significant bit (MSB) first bit-serial architecture for full-search block matching (FSBM) variable block size motion estimation. Since the nature of MSB-first processing enables early termination of the sum of absolute difference (SAD) calculation, the average hardware performance can be enhanced. The architecture has been simulated, synthesized and implemented on a Xilinx Virtex-II XC2V6000 FPGA. The maximum frequency achieved is 340 MHz and the throughput rate is around 18674 macroblocks per second within a -16 to 15 search range. The resource utilization is 3345 LUTs and it can encode CIP resolution video in real time.