An information recording medium capable of converting a stream including seamless connection, which is recorded in a constrained format allowing format conversion from a first format (MPEG-TS) to a second format (MPEG-PS), into a second stream, and an apparatus and method for recording information in the information recording medium. The constrained format is provided for enabling conversion froma first format (for example, MPEG transport stream) to a second format (for example, MPEG program stream). According to the constrained format, when the connection information of the playback portionindicates a seamless playback, the system stream immediately before a seamless connection point ends with a complete data management unit (Capsule).