A method and system for decoding and storing encoded control data delivered via the horizontal overscan area of a video signal. An interactive device such as an interactive toy performs behavior defined by control data that can be encoded into a video signal that can be broadcast or played-back from video tape. The interactive device is equipped with a non-volatile memory that permits the control data to be stored for performance subsequent to the transmission session (e.g., a televised program). The interactive device also may be equipped to perform behavior during the transmission session. The control data is delivered as a series of control data words that include genus codes and sequence codes. Genus codes identify the interactive device to which the data word is directed, so that a particular interactive device will respond (i.e., perform behavior) only in accordance with the control data words including the appropriate genus code. Because video transmissions are subject to video signal deterioration, error grading is used to minimize the effect of such signal deterioration. During a given control data transmission session, control data words will be repeated, so that an interactive device receives several control data words with the same sequence number. Based on the relative gradings, the interactive device will replace previously received control data words of lower quality than subsequently received data words having the same sequence number.