Research On Fast Intra Coding Algorithm In Video Coding Standard H.266/VVC

As an information carrier with a huge amount of data,the compression and transmission of video has always been a research hotspot.In recent years,with the continuous enrichment and development of video applications,the demand for high-definition video is also increasing.The widely used third generation video coding standard,such as HEVC and AVS2,can no longer meet the future market demand.Under this background,the International Organization for Standardization proposed a new generation of video coding standard named as Versatile Video Coding(VVC).VVC introduces many new technologies with excellent compression performance in each module.The introduction of new technology improves the video compression performance of VVC,but also increases the coding complexity sharply at the same time,which limits the application of VVC in scenes such as real-time video coding.The current research on the complexity of VVC coding is not sufficient,and the number of relevant references is limited.Therefore,the research on the fast algorithm for VVC is of great significance.This paper mainly studies the fast algorithm of VVC intra coding process,which mainly involves the process of block partition and mode selection.VVC introduces a new quadtree with nested multi-type tree(QTMTT)structure in the block partition process.This makes the coding units(CUs)in VVC have more flexible shapes and sizes.In mode selection process,VVC increases the number of intra mode from 35 in HEVC to 67,in order to better fit the image texture.These improvements not only improve the performance of VVC intra prediction compression,but also increase the complexity of intra prediction.In order to solve this problem,we propose a fast algorithm using texture information,statistical information and historical coding information in the block partition and intra mode decision module in this paper,which significantly reduces the coding complexity.As for intra block partition module,we propose a Fast GLCM-based Intra Block Partition(GLCM-IBP)algorithm.First,the texture information of CU is extracted and the texture direction is determined by GLCM.Then the binary tree and ternary tree partitions with low possibility are pruned to speed up intra block partition process.The GLCM-IBP algorithm is integrated and tested on the VVC reference software platform VTM-2.0.The test results show that the algorithm can reduce the encoding time by 34.99%on average with little affect on bitrate performance,and the performance is significantly better than the state-of-the-art algorithm.As for intra mode decision module,we propose a Fast Intra Mode Decision Algorithm based on Historical Coding Information(HFIMD).We first analyze the relationship between the first pattern of RDO list(marked as Mode_rdo)and the Most Probable Mode(MPM)list,calculate the distribution probability of the best prediction mode in the RDO list.Then the length of the RDO list is reduced based on the historical attribution information of the best prediction mode.The code integration and performance test is carried out on VTM-2.0.The test results show that the bitrate performance loss of HFIMD algorithm is low,and the encoding time is reduced by 18.48%.Finally,GLCM-IBP algorithm and HFIMD algorithm are jointly tested.The test results show that the proposed algorithm can reduce the encoding time by 44.12%on average with little affect on bitrate performance compared with VTM-2.0.The performance of the proposed algorithm is significantly better than the state-of-the-art algorithms,and the proposed algorithm has good robustness and high encoding time saving efficiency.