"fill screen" video playback option does not work on iPhone X
When using the tap gesture to switch to fullscreen playback on iPhone X, the aspect ratio of the displayed video changes, but the letter box remains the same. When using the aspect ratio button to switch to "fill screen" aspect ratio, nothing happens at all.
See also: https://forum.videolan.org/viewtopic.php?f=36&t=143734 and https://forum.videolan.org/viewtopic.php?f=36&t=143991