Fast inter-mode decision strategy for HEVC on depth videos

Multiview video employs the utilization of both texture and depth video information from different angles to create a 3D video for more realistic view of a scene. Unlike texture, depth video is a gray scale map that represents the distance between the camera and 3D points in a scene. Existing multiview video coding (MVC) techniques including 3D-High Efficiency Video Coding (HEVC) standard encode both texture and depth videos jointly by exploiting texture video information for the corresponding depth video coding (DVC) to reduce computational time as the texture and depth videos have motion similarity in representing the same scene. This strategy has two limitations: (i) more bits and computational time might be required due to the large residuals for the misalignment between depth and texture edges and (ii) switching between different views may require more times due to the increased dependency between texture and depth. In this paper, we propose an independent DVC technique using HEVC (a video coding standard for single view) so that we can improve the rate distortion (RD) performance and reduce computational time by improving switching speed. For this, we use motion features to reduce a number of motion estimation (ME) and motion compensation (MC) modes in HEVC. As we use motion feature which is the underlying criteria for selecting different modes in the standard and then we select a subset of modes which can provide almost the same RD performance. Experimental outcomes reveal a reduction of 48% encoding time of HEVC encoder with similar RD performance and better interactivity.