N17056, Algorithm descriptions of projection format conversion and video quality metrics in 360Lib Version 4

The Joint Video Exploration Team (JVET) of ITU-T VCEG (Q6/16) and ISO/IEC MPEG (JTC 1/SC 29/WG 11) is studying the potential need to include 360-degree video coding technologies in a future video coding standard. The JVET has established a 360Lib software package that can perform projection format conversion between various projection formats as a standalone conversion tool, or in combination with encoding and decoding using HM or JEM reference software. Among the projection formats 360Lib supports, viewport generation using rectilinear projection is also included. Further, 360Lib supports a number of objective 360-degree video quality metrics. This document describes the algorithms used for projection format conversion and video quality metrics in the 360Lib-4.0 software release.