The present invention provides an information recording medium in which an access unit including basic data and extension data is recorded, so as to allow a decoder that decodes only basic data to process the access unit which includes the basic data and the extension data for the next generation.The information recording medium is an information recording medium on which a stream including plural TS packets is recorded, and includes a first access unit which has a first packet that includes basic data as well as a second packet which includes extension data related to the basic data, the basic data being data that can be decoded in a completed state without using the extension data and the extension data being data for improving the quality of data generated from the basic data; wherein the first packet and the second packet are assigned with time stamps indicating relative times at which the first packet and the second packet are respectively inputted to buffers, so that a buffer model of a first decoder does not fail and a buffer model of a second decoder does not fail, the first decoder decoding only the basic data, and the second decoder decoding the basic data and the extension data.