The present invention relates to a multiplexer, a multiplexing method, a program, and a recording medium, whereby TS packets encoded with different encoding methods can be multiplexed. In the event of multiplexing each TS packet of a BS audio TS 173 wherein a BS audio ES 171 encoded with a first encoder is subjected to TS packetizing, and each TS packet of an HQ audio TS 183 wherein an HQ audio ES 181 encoded with a second encoder is subjected to TS packetizing, a control unit assumes a first virtual decoder capable of decoding a BS audio ES alone, and a second virtual decoder capable of decoding an HQ audio ES alone, and determines TS packets to be multiplexed based on an elementary buffer of each virtual decoder, a data transfer rate for the elementary buffer, and multiplexing constraints for random access. The present invention can be applied to a multiplexer configured to multiplex TS packets.