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

Abstract

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 Bipartition 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 AllIntra 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.

Early determination of intra mode and segment-wise DC coding for depth map based on hierarchical coding structure in 3D-HEVC

“…Gu et al skipped DMMs by using the information in rough mode decision [18]. An adaptive mode selection method [19] was raised as an improved version of method [18]. A threshold method was used to early skip DMMs when the variance is bigger than that threshold [20].…”

Fast Depth Intra Mode Decision Based on Mode Analysis in 3D Video Coding

“…In addition, 3D-HEVC adopted several advanced prediction methods for the segment-wise DC coding (SDC) [6], and a depth intra skip mode (DIS) [7], which also cause some complexity. Many fast encoding algorithms were developed to reduce the complexity of the intra coding [8][9][10][11][12][13][14][15] and inter coding [16][17][18] in 3D-HEVC. In particular, there are two research categories to reduce the encoding complexity of the mode decision process in the depth intra coding [8][9][10][11][12][13][14][15].…”

“…For example, the optimum DMM wedgelet is determined through an exhaustive search process [5]. Fast algorithms proposed in [8,9] adaptively skip this full DMM search in flat and smooth regions. A fast algorithm proposed in [10] simplifies wedgelet candidates, based on the corresponding texture information.…”

Low complexity intra mode decision algorithm for 3D-HEVC

“…An adaptive mode selection method is presented in [7] to improve the 3D-HEVC depth intra coding based on the correlation between the best intra prediction and the smallest rough-RD cost value. In [8], a fast technique based on Simplified Edge Detector (SED) to reduce the complexity of the depth intra coding.…”

“…Recently, a number of fast algorithms have been proposed to reduce the computational complexity of 3D-HEVC intra coding [7][8][9][10][11][12]. An adaptive mode selection method is presented in [7] to improve the 3D-HEVC depth intra coding based on the correlation between the best intra prediction and the smallest rough-RD cost value.…”