A demultiplexing apparatus for obtaining and demultiplexing multiplexed data where contents of a digital copyrighted work are multiplexed starting with a header of the multiplexed data, wherein the multiplexed data is made in a way that plural pairs of a content storage box for storing a part of the multiplexed contents and related information storage box for storing information relating to the part of the contents are connected to each other and that the total duration information for specifying total duration needed for playback of all of the contents is contained in the header, and the multiplexed data consists of either a first part or a first part and a second part each including one or more said pairs, depending on the contents, the total duration information indicates time duration needed for playback of the contents contained in the first part in the case where the multiplexed data consists of the first part, and the total duration information consists of a first duration information which indicates duration needed for playback of the contents contained in the first part and second duration information which indicates (i) duration needed for playback of all the contents contained in the first part and the second part or (ii) that the duration is unknown in the case where the multiplexed data consists of the first part and the second part, the demultiplexing apparatus comprising: a data obtainment unit operable to obtain the multiplexed data; a demultiplexing processing unit operable to demultiplex, for each pair, the multiplexed data obtained by the data obtainment unit; a total duration specification unit operable to specify the total duration based on the total duration information contained in the header of the multiplexed data obtained by the data obtainment unit; and a display unit operable to display the total duration specified by the total duration specification unit, the total duration specification unit judges whether the multiplexed data obtained in the data obtainment unit consists of the first part, or the first part and the second part, the total duration specification unit specifies duration indicated by the total duration information as the total duration in the case where it judges that the multiplexed data consists of the first part, the total duration specification unit further judges whether duration needed for playback of all the contents contained in the second part is unknown or not based on the second duration information in the case where it judges that the multiplexed data consists of the first part and the second part, the total duration specification unit specifies the total duration by adding the duration indicated by the first duration information to the duration indicated by the second duration information in the case where it judges that the duration is known, the total duration specification unit judges that it is impossible to specify the total duration in the case where it judges that the duration is unknown, and the display unit notifies that the total duration is unknown in the case where the total duration specification unit judges that it is impossible to specify the total duration. a data obtainment unit operable to obtain the multiplexed data; a demultiplexing processing unit operable to demultiplex, for each pair, the multiplexed data obtained by the data obtainment unit; a total duration specification unit operable to specify the total duration based on the total duration information contained in the header of the multiplexed data obtained by the data obtainment unit; and a display unit operable to display the total duration specified by the total duration specification unit, the total duration specification unit judges whether the multiplexed data obtained in the data obtainment unit consists of the first part, or the first part and the second part, the total duration specification unit specifies duration indicated by the total duration information as the total duration in the case where it judges that the multiplexed data consists of the first part, the total duration specification unit further judges whether duration needed for playback of all the contents contained in the second part is unknown or not based on the second duration information in the case where it judges that the multiplexed data consists of the first part and the second part, the total duration specification unit specifies the total duration by adding the duration indicated by the first duration information to the duration indicated by the second duration information in the case where it judges that the duration is known, the total duration specification unit judges that it is impossible to specify the total duration in the case where it judges that the duration is unknown, and the display unit notifies that the total duration is unknown in the case where the total duration specification unit judges that it is impossible to specify the total duration.