Some of those answers are known

The frame rate is 50fps so at top speed the fastest players can run 30cm (if there is a fast defender running the other way then up to 60cm margin of error).

Offside is from when the player kicks (makes contact) with the ball but due to the above framerate that point almost always happens in between frames. For the Pukki goal the ball had left Mario's foot by about a yard.

The line is one pixel wide so thickness doesn't matter. They just bulk it out for TV.

Biggest problem is none of these but the fact the operator has to guess the furthest forward part of two players bodies and then also the lowest point (for centre of gravity to draw the line). For both there have been clear mistakes for some of these marginal calls.

There's also a problem with the camber of the pitch. According to the premier league website they mapped each pitch before the season started but they will obviously change in places over the season.

Posted By: Kangol Canary, Dec 30, 13:55:11