Adaptive search range by depth variant decaying weights for HEVC inter texture coding

Emerging high-efficiency video coding (HEVC) outperforms H.264 by a gain of 50% bitrate reduction while maintaining almost the same perceptual quality. However, it induces higher coding complexity due to its adoption of recursive block partitioning mechanism in motion estimation (ME) with a fixed search range. For an objective of reducing the computational burden in HEVC, this paper proposes an adaptive search range algorithm by using depth map information. With the aid of depth intensity variations among neighboring blocks, associated weights to the neighboring blocks are derived. The proposed weighted sum of the motions from the neighboring blocks is formulated to provide a suitable search range for each block. The simulation results demonstrated that proposed adaptive search range is compatible to not only full-search (FS) but also fast Test Zone Search (TZS) in HEVC. The proposed algorithm could reduce significant coding time on average with negligible rate-distortion degradation.