480i represents 720 pixels displayed across a screen horizontally and 480 pixels down a screen vertically. This arrangement yields 480 horizontal lines, which are, in turn, displayed alternately. In other words, all the odd lines are displayed, then followed by all the even lines.
480p represents 720 pixels displayed across the screen horizontally and 480 pixels down the screen vertically. This arrangement yields 480 horizontal lines on the screen, which are, in turn, displayed progressively, or each line displayed following another.
