Patent ID: 7747140
Filing Date: 2010-06-29
Classification: G11B,H04N

Abstract:
1. A playback method 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 attribute information used for decoding said access point P-picture, said picture attribute information specifying a reference picture which is necessary to decode a next access point P-picture; said method comprising steps of: identifying a video information unit which includes a start picture to display, in the case of starting playback from said start picture; reading said picture attribute information to identify said reference picture which is necessary to decode a closest access point P-picture preceding said start picture; storing said reference picture in a buffer unit using said attribute information; decoding said reference picture; decoding said access point P-picture using decoded reference picture; and decoding said start picture using decoded 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.