Information storage medium, method and apparatus for reproducing information from the information storage medium and a recording apparatus and recording method for recording video data on the information storage medium

摘要

In an optical disk, a number of video object units arranged consecutively are recorded. The video object unit contains a navigation pack and video packs following the navigation pack, the navigation pack having address information and a picture category relating to a reference picture, the picture category being determined in compliance with the importance level in respect to the reference picture. A sequence of the packets constitutes a stream of nal units classified into a first group of the nal units contributing to produce the reference picture and a second group of the nil unit not contributing to produce the reference picture. In a nal header of the nal unit, reference item information is described that the nal unit belongs to the first group and contributes to produce the reference picture and a type of the payload, the reference item information indicates the priority of the nal unit.