Equirectangular Projection Oriented Intra Prediction for 360-Degree Video Coding

360-degree videos have drawn increasing attention from both industry and research communities with the popularity of virtual reality applications. The 360-degree video is originally represented as a sphere and able to provides omnidirectional view. Equirectangular projection is widely applied to convert the 360-degree video from the 3D sphere to a 2D plane for the purposes of compression and storage. However, the content of the projected video is distorted, which brings challenges for the conventional video coding methods. In this paper, a novel intra prediction algorithm is proposed for 360-degree video coding. The proposed algorithm tries to handle the distortion by adapting the process of intra prediction to spherical domain. The proposed algorithm is implemented in High Efficiency Video Coding (HEVC) test model HM16.16. Experimental results show that the proposed algorithm brings 0.2% BD-rate reduction on average for 360-degree video coding.