Abstract
Various map projection methods are proposed to convert a VR omnidirectional video to a 2D planar video, including Mercator, Equirectangular, Equal-area, Cube projections. The BD-rate comparison of the different map projections has been conducted. However, the performance of the map projections has not been compared using different codec, like widely-used x265 and x264 encoders. In this paper, both x265 and x264 are used to test the performance among the map projections, while S-PSNR is set as metric to calculate the BDrate between H.265 and H.264. Results show that the rate savings of H.265 over H.264 varies from 36.4% to 40.8% in different map projections and Equal-area has lowest bitrate savings of H.265 over H.264. What is more, this paper verifies the performance of the different map projections. Equal-area has the best performance while Mercator has intolerable performance. Last but not least, Equal-area has more bitrate savings relative to Equirectangular using x264 compared with x265.
Li Song
Professor, IEEE Senior Member
Professor, Doctoral Supervisor, the Deputy Director of the Institute of Image Communication and Network Engineering of Shanghai Jiao Tong University, the Double-Appointed Professor of the Institute of Artificial Intelligence and the Collaborative Innovation Center of Future Media Network, the Deputy Secretary-General of the China Video User Experience Alliance and head of the standards group.