Image Codec Based On Multi-platform Technology

This paper's background is scientific research task supported by Beijing Eucation Committee ~ developing image web server based on DSP, and author's study and realization of coding and decoding digital image is introduced on PC and DSP platforms. Firstly this paper introduces significance of image coding, theory of image coding, international criterion of image coding, and then introduces the features of c6000s DSP and environment of software developing. Realizing JPEG compression encoder in C language on PC after studying JPEG criterion. But the purpose is to realize image coding by hardware, so the program modified must be transplanted to DSP. Mostly file operation is modified to memory operation of DSP. Embeded image web server is designed and realized, using C6711 and RCM3200.JPEG code is transplanted from PC to DSP. From much research and experiment, five frames, with 720*576 and YUV2:1:1 are compressed every minute. On RCM3200 platform, active refurbishing web with CGI function is developed.Images with different compression ratio are gained by modify the Q (quality) parameter during the experiment applied on this image process platform. Results of the experiment imply that decline of the image quality is unconspicuous when the Q parameter ranges from 100 to 30. When the Q parameter is set to 25, the image quality drops distinctly. Then a conclusion is drew that Q parameter should be set about 50 to obtain both acceptable image quality and compression ratio.