The Design And Implementation Of The MPEG-4 Encoding Technology Based On DSP

Video code is the technology of multimedia communication, which not only affects the bandwidth, but also affects the image quality. With the development of multimedia technology and network applications, data compression becomes more important, in which the video code is the kernel. Many multimedia compression and coding standards progress are perfect continuously.MPEG-4 plays an important role in the multimedia field. Due to its object-based idea, it has the virtue of high compression ratio, scalability, inter-activity with users and so on. The excellent performances and low price of Blackfin series DSP of ADI Corporation makes it be focused more and more attention. In this thesis, some methods to realize the MPEG-4 on BF561 to realize the real-time compress image data based on the characters of ADSP-BF561 are studied.In this thesis, firstly, the video compression principal is introduced , the reason that uses BF561 is explained, and the core technologies of MPEG-4 are analyzed. Based on the prior work, a scheme of MPEG-4 SP encoder has been proposed, The flow chart, and MPEG-4 SP video compress function with the C language procedure in the VC++ environment is carried out. Secondly, DCT and Motion Estimation algorithm are studied in detail, the correlation of the motion vectors and the early stop criterion are analyzed, an roved diamond search algorithm for block-matching motion estimation based on estimation has been proposed. Due to the characters of ADSP-BF561 dual cores DSP, a parallel algorithm based on the Macro block is designed. Finally the characters of hardware are considered, the optimization of memory, MA controlling and code has been discussed for the encoder. The efficiency of encoder is greatly improved with these optimizations, the MPEG-4 coding rate has arrived at 30frame/s, which can get a perfect result.