[Marcos]

I use to try and guess at a perfect square by eye, using the Video Calibration in the System Prefs. Problem is it has a black background that gives you no reference.

It is a lot easier to calibrate the pixel ratio when you're paused inside of a video with the same aspect ratio as your TV. Then it will be much easier to match the black borders on the top and bottom of the image with the edges of your TV.

[langmarker]

Or you can just use a tape measure.

[elupus]

Hardly any TV have perfect aspect ratio anyway. So if you use a tape measure, you will get black bars since the video doesn't match the TV.

It's just silly to get it that accurate. Imho, make it reasonably square, turn up allowed aspect ratio error in settings so xbmc tries to fill the screen even if the aspect is a little bit off.