Transmitting data packets received from a non-constant delay medium includes storing the data packets in a buffer (Fig 2, Ref 48), determining a play-out schedule (Fig 2, Ref 78) for the data packets based on timing information in the data packets, and transmitting the data packets from the buffer in accordance with the play-out schedule. Two of the data packets may contain time stamps and the play-out schedule may be determined based on a difference between the time stamps.