Auto Layout In Objective-C Can Somebody explain it?

This has to do with the checkbox that he mentions labeled "Constrain to margins". With Interface Builder, you need to select if you want the constraints you set to be relative to the margins that iOS sets or if you want it set to the edges of the screen. iOS automatically selects margins for you to make sure that elements never get pushed up against the edge of screen and look weird, but that isn't always what you want. The default that is set when you bring up that constraints view in Interface Builder is to add constraints relative to the margins, which are closer to the content than the edges of the screen. Thus, the numbers representing the distance of the constraint will be smaller than if the box was unchecked. If you'll notice, Pasan unchecked this box a few seconds earlier in the video, but that checkbox resets every time you open that popover, so even though the numbers were bigger when he closed it at first, they were smaller again when he opened it the next time