Patent ID: 7113523

Claim:
A data multiplexing device comprising: a plurality of buffer memories which store a plurality of packet data strings constituting a plurality of data elements constructed in the form of transport stream packets; a multiplexing means which has a switch means for switching said buffer memories and which time-division multiplexes said plurality of packet data strings to provide an output by sequentially time-division switching said buffer memories with said switch means, wherein said transport stream packets comprise a scramble key extract means for extracting from the multiplexed data a scramble key corresponding to each data element and a descramble means for descrambling the transport stream packet for each data element contained in the multiplexed data by using a scramble key extracted by the scramble key extract means, such that each data element can be descrambled separately by descrambling the transport stream packet for each data element corresponding to a scramble key by using the scramble key; and a switch control means which selects, according to an input rate for said packet data strings, said plurality of buffer memories switchable by said switch means, wherein the input rate is a bit rate used as an index in reference to an amount of encoded bits generated by an encoding controller.