Implementation And Optimization Of AVS Decoder On PC Platform

The first Chinese audio-video coding standard AVS ("Information Technology Advanced Audio and Video Coding" standards)is the basis standard in digital audio and video industry, it possesses independent intellectual property rights and has reached the international advanced level both in technique and in performance. AVS standard is established mainly for compression requirements of the moving image with large size and high-quality in the application of digital TV broadcasting, digital storage media, network communications, stream media and multimedia communication. The MMXTM technology which developed by Intel Corporation is the extension for the Intel architecture (IA) instruction set. The single instruction multiple data technology is adopted in this technology and multipe data elements is treated in parallel, which can largely improve treating performance of the application program on the two or three dimensional graphics and images, thus improving running speed of the multimedia and communication software. Aiming at the realization and optimization of the AVS Video decoding algorithm on the PC platform, the content and major research achievements in this paper are as follows:Firstly, the key technologies and features of AVS standard are analized and application of the multimedia instruction in the area of video and image are introduced in this paper. According to a serious of performance analysis on the AVS reference decoder and combining with advantages of current popularized decoder, the C language realizing scheme confirming with the AVS standard decoding algorithm is designed at the same time.Secondly, the key technology and characteristics of the intra decoding algorithm is studied emphatically, among which entropy decoding,intra prediction and loop filter algorithm is improved, integrated code of the I frame decoder is programed at the same time, full I frame decoder is realized, test on the new decoder is got, and comparison and analysis is made with reference decoder in detail. The results showed that speed of the new decoder is improved three times than that of the reference decoder, and the new decoder can realize real-time decoding.Finally, the MMXTM technology and its applications in the video compression algorithm are discussed in the paper, and programming essentials of the MMXTM technology are deeply studied. According to analyse on time consuming modules in the new decoder, parts which can be optimized based on the multimedia instruction are confirmed, and the inverse transform module, loop filter module and intra prediction module is developed and realized based on the SIMD instruction. Comprehensive testing results show that optimizing program by using the MMX can further improve decoder speed without changing image qualtiy. To sum up, the research content in this paper almost covers all main links in realizing the AVS decoding algorithm on the PC platform, which provides effective references for further performing of the decoder function and realizing of the SD and HD decoding on the PC platform.