A method of and apparatus for modifying a video signal such that a video picture can be reproduced on a television receiver in response to the modified video signal, but if the modified video signal is transmitted and then recorded on a video signal recorder, an accurate video picture cannot be reproduced if that recorded modified video signal subsequently is played back. The vertical blanking interval containing one set of equalizing pulses followed by a set of vertical synchronizing pulses followed by another set of equalizing pulses is modified by replacing a portion of the vertical synchronizing pulses and a portion of the set of equalizing pulses following the vertical synchronizing pulses with simulated equalizing pulses in at least some of the vertical blanking intervals. The amplitude and frequency of the simulated equalizing pulses are equal to that of the actual equalizing pulses.In one embodiment, the modified video signal is transmitted via, for example, cable or RF transmission. In another embodiment, the modified video signal is recorded on a master recording medium. If the master recording medium subsequently is reproduced, the resulting, reproduced modified video signal can be transmitted for video display. However, if a copy of the master recording medium is made, an accurate video picture cannot be reproduced from subsequent reproduction of the copy medium.