Geometry-Corrected Deblocking Filter for 360° Video Coding using Cube Representation

In 360° video, a complete scene is captured, as it can be seen from a single point in any direction. Since the captured 360 images are spherical, they cannot be converted to planar images without introducing geometric distortions. The nature of these distortion depends on the used projection format.This paper introduces an approach to reduce artifacts occurring when encoding 360° video which has been projected to the faces of a cube. In order to achieve this, the operation of the deblocking filter is modified such that the correct pixels with respect to the 3D geometry are used for filtering of edges.The method is evaluated on the set of sequences defined by the Joint Call for Proposals on Video Compression with Capability beyond HEVC. While the method has almost no impact on the objective coding performance, the visual quality is still clearly enhanced. Edges of the cube, previously visible as coding artifacts, are mostly removed with the proposed method.