Research Of Wireless Vedio Communication Based On MPEG-4

With the development of wireless and broadband IP telecommunication technologies, multimedia communication progresses rapidly and lots of video services come to the stage. MPEG-4, international video compression standard adapting Wireless video transmission conforms to developing trend of modern video compression , has lead the research in related fields.First of all, this paper has analyzed the theory for digital video based on the MPEG-4, MPEG-4 Simple Visual Profile to wireless video communication are presented and video encoder pattern based on the MPEG-4 Simple Visual Profile has been achieved. Afterwards the paper has emphasized two key techniques in MPEG-4 encoder: Motion Estimation and DCT, analyzed MPEG-4 error resilience.Motion Estimation and DCT take the largest time in all parts of MPEG-4 encoder. In this paper, the coding methods are studied to increase coding speed. Firstly, The paper has concluded some typical ME algorithm, Afterwards realized diamond search arithmetic which isrecommend by ISO, then improved DS. Secondly, to DCT a novel method detecting all-zero motion vector and DCT coefficients in advance is proposed, which can greatly improve the coding speed. Lastly, the implementation of MPEG-4 video codec based on wireless MMX technology is discussed. Some methods of instruction and algorithm optimization are proposed according to the architecture and instructions. The video codec optimized with the methods can meet the requirement of the application of wireless video communication.At the same time, we go deep into the research of the technology about error resilience for video transmission based on the MPEG-4, some available methods about error correcting code are presented, then proposes a low-complexity architecture of MPEG-4 error resilience mode, which reduce availably the system cost of error resilience processing. Compressed video can be transmitted efficiently through wireless channel by these methods.