A method of content substitution involves receiving an ordered stream of packets containing content marked by a first packet identifier (PID) and one or more substitute content portions marked by one or more secondary PIDs, where the number and placement of packets marked by secondary PIDs ahead of packets marked by the first PID in the stream is retained during transmission of the ordered stream of packets; the ordered stream of packets have an odd or even number of packets with the PIDs after a packet with a first PID; initiating processing for display or storage of content contained in packets having the first PID; initiating processing for display or storage of content contained in packets having a selected secondary PID that meets a substitution criterion; and either deleting or processing the content having the first PID depending upon a number of received intervening packets having secondary PIDs that reside between the packets having the first PID and the packets having the selected secondary PID that meets the substitution criterion, where deleting or processing is determined by whether the number of packets is an odd or an even number. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.