Design And Implementation Of Fast Intra Prediction Encoder Based On HEVC

The HEVC(High efficiency Video Coding)is a new video coding standard which is developed by ITU?T and ISO/IEC in 2013.Compared with H.264 coding standard,it can reduce the code rate of 50% under the same video quality.Intra coding is one of the core modules of coding standard and it aims to eliminate the spatial redundancy in frame.Compared with H.264/AVC,the HEVC intra coding algorithm uses a more flexible partition structure and up to 35 intra prediction modes to further reduce the code rate of intra coding.However,it has higher computational complexity and it is hard to work at real?time,which limits the application of HEVC standard.Therefore,the research of HEVC make great scenes.In this thesis,the correlation between image features and intra coding is analyzed.A fast intra coding algorithm for HEVC is proposed,and the design and implementation of intra encoder are carried out for the algorithm.The main works of this paper includes:(1)A fast division algorithm for intra coding tree unit(CTU)quadtree is proposed.This algorithm reduces the number of Rate Distortion Cost computation by advance division of coding unit(CU)and early termination of CU division.(2)A fast intra prediction mode selection method for prediction unit(PU)is proposed,which uses the correlation between the texture features and the optimal prediction mode to quickly select the candidate mode for prediction.By using this method,the computation of 35 kinds of HAD cost can be avoided.(3)Finally,the hardware implementation of the HEVC intraframe encoder is studied.A two?stage pipeline hardware structure is designed.The first stage is the prediction acceleration unit.In this stage,for the proposed two fast algorithm,parallel method is used to extract image features,then the CTU quadtree division advance decision and PU prediction mode rough selection are performed.The second stage is the intra encode unit.Based on the calculation results of the first level,the rate distortion optimization method is used to get the final division methods of CTU quadtree and best PU prediction mode.Then,encoder completes the coding of CTU.The results show that the designed intra encoder can meet the real?time encoding requirement of 1080p@30fps video at 600 MHz clock frequency.