Abstract: Disclosed are apparatus and methods for synchronized interleaving of multimedia data arriving from distinct sources. The invention independently buffers the incoming data streams and determines the amount of presentation time associated with each data element or byte of each data stream. The invention then draws data from the buffers at varying rates that reflect these differences, continuously presenting the withdrawn data to an interleaving module at data-streaming rates that reflect equivalent presentation-time rates. The invention also includes means for disabling synchronization when one type of data is streamed at a particularly high or low rate, resulting in buffer overload (with either the high-rate data or all data other than that transferred at the low rate).