An apparatus for synchronizing the initiation of the playback of packetized multimedia data received asynchronously in each receiver in a system, and for synchronizing the real time playback in a plurality of receivers in the system, from the transmitter over a wired communications medium. The clocks in the transmitter encoder and the receiver decoders operate asynchronously but at substantially the same rate. Initiation of playback is synchronized according to the arrival time of a first received data packet having a zero-valued retransmit number. Real time playback among a plurality of receivers is synchronized according to a measured time difference between an operating rate of the encoder and an operating rate of the decoder.