  This paper describes the subjective experiments and subsequent analysis
carried out to validate the application of one of the most robust and
influential video quality metrics, Video Multimethod Assessment Fusion (VMAF),
to 360VR contents. VMAF is a full reference metric initially designed to work
with traditional 2D contents. Hence, at first, it cannot be assumed to be
compatible with the particularities of the scenario where omnidirectional
content is visualized using a Head-Mounted Display (HMD). Therefore, through a
complete set of tests, we prove that this metric can be successfully used
without any specific training or adjustments to obtain the quality of 360VR
sequences actually perceived by users.
