Hi, thanks for the reply. So for example, "Avatar (2009) 3D-SBS.mkv" is one such video. To clarify -- it is a 3D movie and recognised as 3D, but Skybox treats it as a VR 180º video so the frame is stretched all the way to the top and bottom of the field of view, rather than being in a rectangle of the correct aspect ratio.
If I change it manually the player now seems to remember the right selection in the future for that movie, which is cool, but I'm just not sure why it isn't picking it up in the first place.
Thanks
PJC