Abstract: An information recording medium includes a lead-in area and a data area for storing contents information. The lead-in area includes a first lead-in information area and a second lead-in information area. The first lead-in information area corresponds to a first playback mode. The second lead-in information area corresponds to a second playback mode different from the first playback mode. The first lead-in information area has a first depth and is designed for storing lead-in information related to the contents information stored in the data area. The second lead-in information area includes pre-pits having a second depth greater than the first depth. The pre-pits represent predetermined information, such as information of copyright protection, related to the contents information stored in the data area.

Abstract: Video data pieces are classified into groups according to prescribed rules. A cut number assigned to each of the groups is decided on the basis of the length or lengths of a video data piece or pieces in each of the groups and the number of the video data piece or pieces in each of the groups. A cut or cuts are extracted from the video data piece or pieces in each of the groups. Regarding each of the groups, the number of the extracted cut or cuts is equal to the decided cut number. Digest data is generated from the extracted cuts for all the groups.