An Adaptive CU Depth Selection Mechanism Based on Visual Sensitivity for HEVC Inter Coding

High Efficiency Video Coding (HEVC) is the latest video coding standard. It aims to provide significant improvement of compression performance with considerable increment of computational complexity, compared with all exiting video coding standards. In this paper, we propose an adaptive CU depth selection mechanism (ACDSM) for inter mode decision. To avoid unnecessary CU partition by rate distortion optimization with Lagrange multiplier, an adaptive CU depth is derived from spatial homogeneity based on visual sensitivity, intensity gradient filter and the temporal stationarity characteristics of video objects, in ACDSM mechanism. Experimental results demonstrate that the proposed algorithm provides averagely 32.93% encoding time reduction while maintaining the same level of perceptual visual quality, compared with HEVC test mode (HM 10.0) encoder with low-delay configurations.