Patent ID: 9743113
Date: 2017-08-22
CPC Classifications: H04N

Claim:
1. A video predictive decoding method executed by a video predictive decoding device, comprising: an input step of inputting (i) picture data in a compressed form for reproduction of a target picture [k], the picture data resulting from execution of predictive coding, using a first set of reference pictures, on the target picture[k] and (ii) buffer description information BD[k] in a compressed form which describes the first set of reference pictures used to predictively encode the target picture[k], wherein the first set of reference pictures are described in the buffer description information BD[k]with their identification numbers relative to identification numbers of a second set of reference pictures described in buffer description information BD[m] which are used to reproduce another target picture[m] different from the target picture[k]; a reconstruction step of decoding the picture data to reproduce the target picture[k]; a picture storage step of storing the reproduced target picture[k] as a reference picture to be used for decoding of a subsequent target picture; and a buffer management step of controlling the picture storage step, the buffer management step comprising: prior to reproduction of the target picture[k], referencing the buffer description information BD[m] to restore the identification numbers of the first set of reference pictures described in the buffer description information BD[k]; decoding the target picture[k] using the first set of reference pictures of the buffer description information BD[k] whose identification numbers are restored; and controlling the picture storage step on the basis of the decoded buffer description information BD[k], wherein referencing the buffer description information BD[m] to restore the identification numbers of the first set of reference pictures described in the buffer description information BD[k] comprises: restoring an index m identifying the buffer description information BD[m]; restoring a value of deltaBD representing a difference between identification numbers of corresponding reference pictures described in the buffer description information BD[m] and the buffer description information BD[k], restoring a plurality of flags ibd_flag[j] each adapted to take multiple values one of which is indicative of both: restoring the identification numbers of the first set of the reference pictures described in the buffer description information BD[k] based on the restored index m, the restored value of deltaBD and the restored flags ibd_flag[j], and wherein, when the ibd_flag[j] takes a value that indicates that an identification number of the j-th reference picture described in the buffer description information BD[m] is used for restoring an identification number of a reference picture described in the buffer description information BD[k], a deltaPOC[i] that is an identification number of an i-th reference picture described in the buffer description information BD[k] is derived by adding a value of the deltaBD to a value of deltaPOC[j] that is an identification number of the j-th reference picture described in the buffer description information BD[m].