Octagonal Mapping Scheme for Panoramic Video Encoding
Chengjia Wu, Haiwu Zhao, Xiwu Shang · IEEE Transactions on Circuits and Systems for Video Technology · 2018
As modern video coding standards are not designed to code panoramic videos, the pixels on the sphere need to be sampled onto a rectangle, and this process is called mapping. The mapping schemes generally include two steps: sampling points on sphere and arranging points into one compression-friendly rectangular frame. Traditional mapping schemes including equirectangular and cubic mapping have high sampling density on some sampling areas, which result in wasted pixels. In this letter, we propose a novel octagonal mapping scheme, which can decrease the oversampling areas and arrange points into an octagon. The octagon can be reshaped and rearranged into a rectangle before encoding. Experimental results demonstrate that the proposed mapping scheme saves more bitrates, compared to the existing mapping schemes.