Research On Inter Prediction Algorithm And All-zero Block Detection Of AVS Video Coding

For the increasing demand of multimedia information, the multimedia technology is developing very quickly. As the core of multimedia technology, video processing technology is quick developing too. A large number of video data has put forward a very high demand of transmission bandwidth and storage space, so the video codec technology which encodes and decodes the video sequence has become one of the hot issues of the research and industrial application. AVS (Advanced Audio-Video Coding-Decoding Standard) video standard is developed by the Audio Video Coding Standard Working Group of China, which is one of the most advanced video compression standards available and has the own intellectual property rights. AVS has low complexity, high compression ratio, high image quality, wide application range, low patent cost. This paper carries out AVS video encode optimization in aspects of structural adjustment, source code optimization and optimized implementation of core algorithm. These lead to obvious raise in encoding efficiency.An introduction is given which is about the encode principle and encode flow of AVS video codec standard, together with the key technologies, including inter prediction, intra prediction, sub-pixel interpolation, transform and quantization, loop filter and entropy coding, etc. The comparison between AVS and H.264/AVC which is the most popular video codec standard abroad is given. Then, based on the reference software rm52j provided by AVS video codec technology standard group, we do the structural and source code introduction, which will provide foundation for the following algorithm improvement and code implement.Rate distortion optimization mode decision is used in AVS standard. All the modes of inter prediction will be traversed, which results in severely time-consuming. A fast inter prediction mode decision algorithm based on the time and texture characteristic of macroblocks. Speed improvement is very obvious for both video with fixed background and fast-motion video. This algorithm can save the coding time obviously while maintaining the coding performance.According to the characteristic of integral transform, this paper uses an efficient all-zero block determination rule for 8×8 integral discrete Cosine transform and the corresponding threshold. All-zero detection is one of the common optimization methods oriented towards low bit rate video coding, especially when combined with inter mode prediction based on skip blocks prediction. By using the algorithm the time would be reduced greatly which taken by implementing transform, quantization, inverse transform, inverse quantization and block reconstruction with negligible loss of PSNR and increment of bit rate. Using all zero block detection algorithm in motion estimation will reduce the times of motion search, improve motion estimation efficiency and enhance the encode performance.