The VideoLAN Forums

"Force subtitle position" has no effect in full screen
What to do?

If subs are hard coded then they'll stay in the position the author intended regardless of what you do.

If you're adding subs to a video then use the option in the Subtitles / OSD menu to force a position. For example, if you want subs on top of the video adding 600px to the "Force subtitle position" menu should achieve that goal. You'll need to save the setting and then exit / restart before you play the video.

I expected the subtitle position in "zoom original" to be in the same proportional position when in "fullscreen".
But this is not the case, in both cases it is how many pixels from the bottom.
So this is not a bug, it is a feature working in a different way than I expected.
Now I understand!