Disclosed is a system and method that provides rate controlled insertion of asynchronous data into a synchronous stream in a broadcast system. A calculation of the transmission time for an asynchronous data file is determined from the file size, available data transfer rate, redundancy transmission factor, bandwidth scale factor and connect time latency. Transmission time may be employed to schedule transmission of asynchronous data for use at a predetermined time. Transmission time for multiple files may be combined to determine a transmission start time for a first file such that a last asynchronous file is transmitted by a predetermined time.