The Development Of AVS Source Decoder Base On TMS320DM642

AVS(Advanced coding of audio and video) is the audio and video standard of our Chinese intellectual property right. At the same bit rate, its performance is higher than MPEG-2 standard, and equals to H.264. In the domain of video and audio, it is necessary for us to develop our own video and audio standard because of the high patent expense of MPEG-2 and H.264.The limited processing capability of the CPU, which also needs high speed decoding, makes it essential to develop the high efficient video decoder, which is the key for the success of the multimedia operation.In recent years, the television system has experienced great development from the analog black-white television to the analog colored television and the digital television. At present, the television system has stepped into the transmissive period from analog television to digital television. The huge digital television market has brought the enormous potential opportunity for the development of the digital television equipment.In this paper, an idea about realizing a completely programmable digital television source coder based on generic DSP is realized. Acccording to the processing capability of the current generic DSP, this paper successfully designs and develops the software system of digital television source decoder which is based on the generic DSP—TMS320DM642. This software system realizes the input of transport stream and develops the video displaying. In addition, high-speed data exchange between on-chip and off-chip memory space is implemented successfully with software means. This system can also act as image-capturing and image-matching system.The key algorithms of the digital television source decoder—transport stream de -multiplex, video decoding, has been deeply researched and concretely realized. In order to enhance the performance of source decoder, various kinds of methods have been adapted to optimize these codes, especially the variable length decoding, IDCT (Inverse Discrete Cosine Transform) and motion compensation coded in assemble language. Then the performance of the source decoder is enhanced.The experimentations have showed that the scheme offered in this paper can implement the functions of digital SDTV (Standard Definition Television) source decoder. For the limitation of TMS320DM642 processor's capacity, the digital HDTV (High Definition Television) source decoder could not been realized. However, with the development of DSP, the completely programmable solution of HDTV source decoder with single chip of generic DSP will be feasible.