Backward view synthesis prediction using virtual depth map for multiview video plus depth map coding

View synthesis prediction has been studied as an efficient inter-view prediction scheme. Existing view synthesis prediction schemes fall into two types according to the pixel warping direction. While backward warping based view synthesis prediction enables block-based processing, forward warping based view synthesis prediction can handle occlusions properly. This paper proposes a two-step warping based view synthesis prediction; a virtual depth map is first generated by forward warping, and then prediction signals are generated by block-based backward warping using the virtual depth map. The technique of backward-warping-aware depth inpainting is also proposed. Experiments show that the proposed VSP scheme can achieve the decoder runtime reductions of about 37% on average with slight bitrate reductions relative to the conventional forward warping based VSP. Compared to the conventional backward warping based VSP, the proposed method reduces the bitrate for the synthesized views by up to 2.9% and about 2.2% on average.