In order to allow the generation of a time stamp in consideration of a frame skip even in the case where the frame skip is generated, a PES generation section of a multiplexer detects the number of skipped frames by analyzing elementary video streams output from a video encoder to determine a PTS on the basis of the time difference between frames calculated on the basis of the number of skipped frames. Then, a frame to which a PTS is to be placed with the above stream analysis is cut out to insert the PTS into a PES header of this frame to be transmitted to the transmission channel.