Patent ID: 7310373

Claim:
A picture decoding method for decoding a target picture, said method including a decoding step of performing predictive decoding on the target picture with reference to an already-decoded picture, wherein, in the decoding step, when the target picture is a P picture which is capable of being predictive-decoded in a P-mode decoding, the target picture is predictive-decoded with reference to an already-decoded I or P picture but without referring to any already-decoded B picture, and when the target picture is a B picture which is capable of being predictive-decoded in a B-mode decoding, reference pictures for the B picture are designated from candidate pictures, wherein the candidate pictures can include one or more B pictures which are located between forward and backward I or P pictures closest to the target picture, the forward and backward I or P pictures closest to the target picture, and one or more I or P pictures other than the forward and backward I or P pictures closest to the target picture, but cannot include one or more B pictures which are not located between the forward and backward I or P pictures closest to the target picture.