The Pass Through Lower Boundary register specifies the lower boundary (exclusively) of pass through window.
IMPORTANT: Note that in pass through window registers, the left and top boundaries are inclusive while the right and bottom are exclusive. For example, to pass though a top-left 720P window, these four registers should be set to (0, 0, 1280, 720), respectively, rather than (0, 0, 1279, 719).