There is provided with a video display apparatus comprising: a receiving
unit configured to receive a composite video image generated from a
plurality of video sources; a display unit configured to display the
received composite video image; an area manager configured to store area
information pieces; a position specification unit configured to specify a
position on the composite video image; an area selection unit configured
to select an area information piece from the area information pieces; an
area display unit configured to provide information indicating the area
represented by the selected area information piece to the display unit so
as to superpose the information on the displayed composite video image;
an area change unit configured to change the information; an area
information update unit configured to update the selected area
information piece; and a transmission unit configured to transmit an
update control signal containing the area information piece after update.