A configuration is realized in which a packet delimiter can be discriminated from an MMTP packet string including MMT format data, and a packet can be selectively acquired and reproduced. The MMT format data is input through a broadcast wave or the like, a packet length of an MMT protocol (MMTP) packet including the MMT format data is acquired, and recording data in which an additional header storing the acquired packet length is set before the MMTP packet, is generated, and is recorded in an information recording medium. A reproducing device is capable of discriminating a delimiter of each MMTP packet, according to the packet length of the MMTP packet, read from the additional header, is capable of acquiring reproducing data, for example, image data, from the selected packet, and is capable of decoding and reproducing the acquired data.