Research On Inter/Intra Prediction And Optimization Techniques In HEVC

HEVC (High Efficiency Video Coding) is a new video coding standard that is joint-ly developed by VCEG and MPEG. HEVC adopts the same hybrid video coding as its predecessor H.264/AVC, but each coding tool is improved and enhanced. In compari-son to H.264/AVC, approximately50%bitrate reduction is achieved for equal perceptual quality. In HEVC, the inter/intra prediction, encoder complexity and its optimization techniques are very important for its compression efficiency and practical application-s. This dissertation focuses on the inter/intra prediction and optimization techniques in HEVC. The main contributions are as follows:1. The "competition" based motion vector prediction in HEVC test model HM1.0is investigated. Then a novel motion vector predictor selection algorithm is proposed. The proposed algorithm can effectively prune the candidates list, therefore the num-ber of bits for coding the predictor index is reduced and coding efficiency of motion vector is improved.2. A novel control-points representation and differential coding method for affine mo-tion model is proposed. By exploiting the spatial correlation between adjacent coding blocks, motion vectors at control points can be predicted and thus efficient-ly coded. Four new affine prediction modes are designed and embedded into the HEVC test model HM1.0. In comparison to the original HM1.0coder, significant bitrate reduction is achieved.3. While the flexible block structure and more choices of prediction modes in HEVC provide better coding performance, it dramatically increases the encoder complex-ity. To solve this problem, a novel fast bottom-up pruning algorithm is proposed to reduce the number of mode decision process, and a new fast intra mode deci-sion algorithm is proposed. When the two algorithms are both adopted, about40%encoding time saving is achieved with only0.77%average bitrate increase.