Abstract: The method includes receiving a signal to insert a data effect into a digitally encoded, framed data stream, retrieving a data effect having the same format as that of the data stream, detecting a first data stream frame boundary, inserting the data effect into the data stream at the first data stream frame boundary, detecting a second data stream frame boundary, and resuming the data stream at the second data stream frame boundary. If the data stream can be of more than one format, the format of the data stream can first be determined. The apparatus includes a processor and a multiplexor. The multiplexor is used for inserting the data effect into the data stream. The processor is used for detecting data stream frame boundaries, retrieving from a memory a data effect having the format of the data stream, and transmitting the formatted data effect to the multiplexor. The data stream may be an audio stream formatted in MPEG format (including MPEG-1, MPEG-2, MP3, MPEG-4), AC-3 format (including 2-channel, 5.