When we express sizes, how do we distinguish between encoded size, visible size, and natural size. From what I understand:

• coded size: the resolution of the encoded picture, always a multiple of the macroblock size (eg. 1920x1088).
• visible region: the region of the coded picture that is valid image data (eg. 1920x1080@0,0).
• natural size: the intended display size assuming square display pixels (that is, after applying the pixel aspect ratio).