Rotation : 90°

[radpopl]

BestSource doesn't rotate such MP4 files.
Ultimately, they should appear as vertical videos.
Should I send you an example (privately)?

Width                          : 1 920 pixels
Height                         : 1 080 pixels
Display aspect ratio           : 16:9
Rotation                       : 90°

[myrsloik]

Right, I don't expose that to VS. The required rotation/flipping is only reported in the API. I probably should apply it automatically.

[myrsloik]

What you need to do is exposed in the FlipVertical, FlipHorizontal and Rotation properties already.