Randomly accessible visual information recording medium and recording method, and reproducing device and reproducing method

A playback apparatus for reproducing video data recorded on a medium, said video data comprising a plurality of video units which each include an intra coded I-picture, a predictive coded P-picture including a group of blocks predicted from one picture and a bidirectionally-predictive coded B-picture including a group of blocks predicted from two pictures, at least one of said video units including an access point P-picture coded by motion compensation prediction using an I-picture located at the beginning of a video unit or a selected preceding P-picture, wherein a P-picture or a B-picture following said access point P-picture is coded without referring to any picture located before said access point P-picture, said medium containing picture structure data used for accessing said access point P-picture, said picture structure data including picture type information indicating type of each picture included in each of said video units;

• said apparatus comprising:
• means for identifying a video information unit which includes a start picture to display, in the case of starting playback from said start picture;
• means for accessing said picture structure data and reading said picture type information to identify said access point P-picture included in said video information unit and said I-picture or said selected preceding P-picture used for coding said access point P-picture;
• means for accessing a closest access point P-picture preceding said start picture and said I-picture or said selected preceding P-picture used for coding said access point P-picture according to said picture type information;
• means for decoding said I-picture or said P-picture used for coding said access point P-picture;
• means for decoding said access point P-picture using decoded I-picture or P-picture as a reference picture;
• and
• means for decoding said start picture using said closest access point P-picture as a reference picture, wherein said start picture is decoded without referring to any picture located before said access point P-picture.