Research And Implementation Of MPEG-4 Video Codec Based On The TMS320DM642

Responding to multimedia technology rapidly developing and application domain promptly enlarging, many multimedia compression and code standards progress and perfect continuously. Among them, 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, interactivity with users and so on. For these reasons, MPEG-4 indicates the tendency of the multimedia compression and coding technology. Along with further research of video technology, specially the need of low bit rate wireless video communication application, the embedded video system using MPEG-4 video standards will inevitably be able to widely apply to each domain, the application prospect is exceptionally board.This paper introduces the development of present video compression code technology and the function and new characteristic of international video compression code standard MPEG-4, analyzes the principle and method that realizes the MPEG-4 video code from the elementary theory angle, fully studies the key algorithms of MPEG-4 standard, including the motion estimation, the motion compensation, DCT, quantification and so on, the algorithms which consume too much time is improved. In block match part, improves the diamond search algorithm and introduces the zero motion vector estimatios to reduce the search quantity.Carries on the optimization to the H.263 quantification technology,a intra-frame quantification search table that can avoid the division operation is constructed. Introduces the entire zero DCT macro block estimation algorithm to avoid some unnecessary DCT.Then in view of the DSP software and hardware characteristic, proposes the realization and optimized plan of the video encoder including the improvement to DCT,quantification and using EDMA smartly and so on. Simultaneously this paper according to the theory of MPEG-4 decoding, analyzes the essential technology of VLD, RLD, IQ, IDCT, motion compensation in the decoding, and implements the software prototype of decoder. Fully uses the DSP/BIOS function and TI RF-5(Reference Framework 5) to get the configuration of overall system application program, has completed the MPEG-4 codec software design as well as the DSP implementation.