On an optical disk, video object sets (VTST_VOBS) to be reproduced and
video title set information (VTSI) serving as management information on
the video object sets have been stored. In each video object set
(VTST_VOBS), many data cells, each containing video, audio, and
sub-picture data, are arranged Management information of program chains,
which are combinations of programs to be reproduced one after another,
has been written in a video title set PGC table (VTS_PGCIT). By referring
to the program chain table (VTS_PGCIT) according to the user's input, the
playback order of program chains can be changed, enabling the program
chains to be reproduced one after another in various modes.