Efficient multiview video plus depth coding for 3D-HEVC based on complexity classification of the treeblock

Abstract

High efficiency video coding standard-based 3D video (3D-HEVC) has been extended from HEVC to improve the coding efficiency of multiview video plus depth (MVD). Similar to the joint model of HEVC, a computationally expensive exhaustive mode decision is performed to find the least rate-distortion cost for each treeblock in 3D-HEVC. Furthermore, additional coding tools have been added to 3D-HEVC for improving the coding efficiency of the dependent texture video and depth map. Those tools achieve the highest possible coding efficiency, but also bring a significant computational complexity which limits 3D-HEVC from real-time applications. In order to reduce computational complexity, we propose an efficient multiview video plus depth coding algorithm for 3D-HEVC that adaptively utilizes the complexity classification of the treeblock. The coding complexity model of a treeblock is first analyzed according to the prediction mode and coding mode from the corresponding treeblocks in the reference views. Based on the complexity classification model of the treeblock, we propose two efficient low-complexity approaches, including fast mode size decision and adaptive motion search range selection. Extensive experimental results demonstrate that the proposed MVD coding algorithm can achieve the average computational saving about 60.1% with negligible rate-distortion performance loss in comparison with the original 3D-HEVC encoder.