A system and method for providing ancillary data over compressed multimedia packets. Ancillary data may be added to encoded or compressed packets without increasing the bandwidth required to transmit the packets over a transmission medium. After transmission, the ancillary data can be recovered and the packets restored to their original form without any loss of data or damage to original content. The ancillary data can be presented to a user on-demand, or in response to an event. The content of the ancillary data can also be correlated to the type of event that initiated the delivery or to the content of the encoded or compressed packets.