Research And Implementation Of Real-time MPEG-4 Video Coding And Decoding Software System

The MPEG-4 video compression standard has been paid much attention in research and application, for its high openness, flexibility and efficiency. This thesis work mainly focuses on discussing its capability and implementing its solution in low bit-rate video applications.The block-based model for motion estimation and compensation forms the basis of almost all video standards, for example MPEG-1, MPEG-2, MPEG-4, and MPEG-4 part 10. First this dissertation analyzes and compares current latest motion estimation algorithms, including the Three Step Searching algorithm, 2-D Logarithm Searching algorithm, Diamond Searching algorithm, etc. The Motion Vector Field Adaptive Searching Technology (MVFAST) can even further reduce its searching points and gain higher PSNR than previous algorithms. MVFAST is adopted in this software video coding and decoding system.Second, a high parallel-pipelined VLSI architecture for MPEG-4 motion estimation is proposed in this paper, searching for the best match to the reference block by full search block matching algorithm to enhance the video quality. It possesses the characteristics of low embedded memory, low clock rate with high accuracy, and flexibility to adapt different search window size, aiming at both mobile applications and high-definition fields. Full search block matching algorithm has been mapped onto this architecture using an optimized processing element array that has the ability to evaluate the motion vectors of CIF video real-timely at 8 MHZ clock rate with only 5 Kb embedded memory. The proposed architecture has been prototyped, simulated and synthesized for 0.35 um CMOS technology using FUJITSU CE66 cells. The prototyped architecture consumes 190.3 mW with 3.3 V supply voltage and has core area of 5.52 mm2 with 5 layers of metal. It largely improves the performance to more than 33 times faster with only 34.6% more silicon area cost than the reference motion estimation architecture of MPEG-4 Part 9.Finally, an MPEG-4 based Real-time Video Compression Software System is created, which is optimized by MVFAST motion estimation, Integer DCT, and predicting of zero quantization blocks, to obtain near 100 Compression Ratio (CR) and real-time coding and decoding speed, in the condition of acceptable video quality. It is an integrated digital video remote transmission system and can be applied in remote surveillances, net camera, portable applications, etc.