An apparatus and method for controlling viewing of video programs. The apparatus includes a signal unit for receiving and processing a video signal, a decoding unit for decoding a grade code of a video program contained in the video signal, a key input unit for receiving control data from a user wherein...http://www.google.com.au/patents/US6175718?utm_source=gb-gplus-sharePatent US6175718 - Apparatus and method for controlling viewing of video signals
