is of the form X=Ai, Y=Ej. The warped reference for each macroblock is exactly the same shape and next to each other (no overlap). But, concept-wise only the zoom-center is scaled exactly the same as the picture and rest of them are distored (perspective distortion). So how exactly the global compensation helps in this scenario while using the same parameters A and E for all the macroblocks. Thanks, Kasturi