Study On Key Algorithms And Software Hardware Co-design Of H.264

As the newest video coding standard, H.264 receives widespread concern for its excellent compression performance, high image quality and a good network of affinity, so H.264 has a wide application in the network video transmission, digital high-definition video, and so on.H.264 coding algorithm includes many coding techniques and many complex calculations, which limits the coding speed and the application of H.264. And also, H.264 is in constant development.Therefore, the research and improvement of H.264 coding algorithm and the implementation of H.264 encoder have a great significance.This paper introduces the h.264 standard coding algorithms and the parts of inter-frame prediction and CAVLC entropy coding are optimized. Inter-prediction is composed by two parts-Motion estimation and Motion compensation. Motion estimation, as one of the key algorithm, determines the efficiency of inter prediction.In this paper, combining the characteristics of video motion pictures, one optimized method is proposed for motion estimation. CAVLC entropy coding, as the final step of encoder, uses a lossless encoding method and plays a key role in compressing code stream. Through our research, we find some defects of CAVLC. In this paper, combining the characteristics of coded bits and the process of CAVLC entropy coding, the CAVLC entropy coding algorithm is improved to save more encoded bits and to reduce the transmission bandwidth.Experimental results by different video sequence show that the improved methods can save about 16% ME time on average and can achieve 24.2% ME time saving at best. For CAVLC, the optimized methods can also reduce the encoded bit stream.This paper also discusses the realization of video capture system based on H.264 encoder. Based on SOPC technology, this paper use NiosⅡprocessor, Avalon Bus and flexible custom component to design video capture module, software-hardware interface module and hardware accelerating module and finally implement the H.264 video capture system. The pipelined DCT transform and quantization module, and the Hardware CAVLC module, which are used as custom component to accelerate the video capture system, are also introduce in detail.The entire design is vertified on Altera DE2 platform and has a good application prospect.