Generic segment-wise DC for 3D-HEVC depth intra coding

In 3D extension of HEVC (High Efficiency Video Coding), namely, 3D-HEVC, segment-wise DC coding (SDC) was adopted to more efficiently represent the depth residual for Intra coded depth blocks. Instead of coding pixel-wise residual as in HEVC, SDC codes one DC residual value for each segment of a Prediction Unit (PU) and skips transform and quantization. SDC was originally proposed for only a couple of modes, including the DC mode, Planar mode and depth modeling mode (DMM), which has an arbitrary straight line separation of a PU. This paper proposes a generic SDC method that applies to the conventional angular Intra modes. For each depth prediction unit coded with Intra prediction mode, encoder can adaptively choose to code pixel-wise residual or segment-wise residual to achieve better compression efficiency. Experimental results show that proposed method can reduce the total bit rate by about 1% even though the depth views altogether consumes relatively low percentage of the total bit rate.