Fast Intra-Mode Decision Algorithm for Virtual Reality 360 Degree Video Based on Decision Tree and Texture Direction

摘要

Virtual reality 360-degree video is now widely used in various fields. However, the huge amount of data caused by its high resolution increases the coding complexity. While the existing video coding framework, such as HEVC, is not optimized according to the characteristics of virtual reality video, in order to accelerate the speed of intra-mode decision process in video coding, a new algorithm is proposed in this paper. Each virtual reality 360-degree video frame is divided into two regions, namely the pole region and the equatorial region. The number of candidate modes in the pole region is reduced in advance according to the statistical distribution pattern of the modes, and intra-mode in the equatorial region is determined by the cart decision tree using the texture contrast of the coding unit. The experimental results show that compared with the original HM 16.20, the proposed algorithm can save the coding time by 28.3%, while only increasing the bd-rate by 0.612%.