AVS Coding Algorithm Implementation And Optimizing Based On Fixed-Point DSP

AVS standard is digital audio/video encoding and decoding technologies national standard made in China independently,the second part——video is made for meeting moving image compression in the applications such as adapting to digital video broadcasting,digital storage media,network streaming media,multimedia communication and so on.The subject researched on the part realized in real time based on DSP platform.The text introduced the principle of AVS coding algorithm and the key technologies,the structure and feature of the chip of DM6446,the ARM subsystem and video subsystem,especially introduced DSP subsystem and instruction set summarized by myself and the design of the method of floated-point division based on fixed-point chip,discussed the principle of intra encoding,the method and related program design,optimizing the functions which was consuming much time in AVS algorithm in linear assemble language, improving efficiency of intra coding and so on.The subject researched on realizing AVS algorithm in real time based on the fixed-point chip of TMS320DM6446,mainly finished the task as following:①Having finished floated-point division(including:float and double division)based on the hardware platform,on the equivalent precision with C language,instruction cycles have reduced 18.2%(float)and 39.3%(double) independly;②Having realized two key modules in AVS algorithm——intra coding module,ICT and anti-ICT transforms,quantization and dequantization module based on TMS320DM6446.Including programming and optimizing in C language,and optimizing in linear assemble;③Having optimized functions which was consuming much time in AVS algorithm in linear assemble language,such as SATD and SAD,1/4 pixel interpolation,ICT and anti-ICT transforms,quantization and dequantization, improving efficiency of intra coding further;④By readjusting the structure of the whole program reasonably,making good use of memory resource,having realized transplantation of AVS algorithm. After running on the hardware platform of TMS320DM6446,having got the AVS stream of QCIF formate and frame rate of 13.49fps;after encoder encoding, the average SNR of luma was more than 38.5dB,the average SNR of chroma U and V may get up to more than 41.5dB.