A method of transmitting timing critical data via an asynchronous channel without changing any datum to be transmitted. The timing critical data can be an MPEG transport stream. The asynchronous channel can be a computer or telephone network, a digital storage media such as a digital VCR, or a digital interface. The method involves tagging each transmission unit of the data stream, before inputting to the channel, with timing information, and using the timing information at the output end of the channel to recreate the proper data timing, Various schemes are described for packing the timing information tags with each or a plurality of transmission units.