Patent ID: 8798447

Claim:
A playback method for reproducing a video information stream recorded on a medium, said video information stream comprising a plurality of video information units each of which includes an intra coded I-picture, a predictive coded P-picture and a bidirectionally-predictive coded B-picture, said video information stream including a first video information stream representing a primary video sequence, a second video information stream representing secondary video sequence which is presented with said primary video sequence and an access point map which includes access point information and I-picture size information of said first video information stream and said second video information stream; said method comprising steps of: identifying a closest one of I-pictures preceding a start picture corresponding to a start point of playback for said first video information stream and a second video information stream; locating a position of identified I-picture for said first video information stream and said second video information stream by referring to said access point map; and decoding said identified I-picture for said first video information stream and said second video information stream; wherein in a case of performing trick play, positions of I-pictures used for trick play, which are selected in accordance with a playback speed, are derived by referring to said access point map.