Fast bi-partition mode selection for 3D HEVC depth intra coding

This paper proposes a fast mode decision algorithm for 3D High Efficiency Video Coding (3D-HEVC) depth intra coding. In the current 3D-HEVC design, it is observed that for most of the cases, full Rate-Distortion (RD) cost search of Bi-partition mode could be skipped since most coding units (CUs) of depth map are very flat or smooth while Bi-partition modes are designed for CUs with edge or sharp transition. Using the rough RD cost value calculated by HEVC Rough Mode Decision as a selection threshold, we propose a fast Bi-partition modes selection algorithm to speed up the encoding process. The test result for the proposed fast algorithm reports 34.4% encoding time saving with 0.3% bitrate increasing on synthesized view for All-Intra test case. Moreover, by simply varying the selection threshold, we can make a tradeoff between encoding time saving and bitrate loss based on the requirement of different applications.