PURPOSE: To make upper and lower multiple signals inconspicuous and to reduce interference by obtaining a difference between adjacent picture elements in a horizontal direction to be difined as an auxiliary signal and multiplexing the auxiliary signal on upper and lower non-picture parts.

CONSTITUTION: A VLPF 102 extracts only the vertical low frequency components of input video signals and supplies them to a 3/4 compression circuit 104. The circuit 104 compresses valid scanning lines from 480 to 360 by thinning out the scanning lines of low frequency signals from 4 to 3 and supplies them to a switch 106. On the other hand, a VHPF 103 extracts only vertical high frequency components and supplies them to a 1/4 compression circuit and they are supplied to a difference circuit 200 as the auxiliary signals for which the valid scanning lines are compressed from 480 to 120. The switch 106 is switched to an (a) side and supplies main picture signals supplied from the circuit 104 to an output terminal 107 when video signals are the main pictures of a center part and is switched to a (b) side and supplies difference signals from the circuit 200 to the terminal 107 at the time of the upper and lower non-picture parts. Then, when signals outputted from the terminal 107 are projected to a present receiver, letter-box pictures whose upper and lower parts are turned to the non-picture parts are obtained.