How do I center resized window in fullscreen mode?

[Ayabara]

When I view video clips I like to do it in full screen mode with black edges around it. When I enter fullscreen mode the video fills the screen (or is not resized if I choose that option). Then I use the resize function to make it smaller, and it places itself in the top left corner of my screen.

Is there a way to make the video be in the center of my screen. Can I open a video, zoom to 123,5% and then enter a full screen mode where I see my video at 123,5% of the original size, with black background around it?