Patent ID: 7822120

Claim:
A moving picture coding method executed by a moving picture coding apparatus, for coding a moving picture with motion compensation using a motion vector, the moving picture coding apparatus including a storage area for storing at least one motion vector used in motion compensation of a current picture to be coded, the moving picture being a sequence of pictures, each of the pictures being made up of a plurality of blocks, the method comprising: a step of generating limitation information indicating a limitation on an amount of motion vector data to be stored in the storage area in the case where the at least one motion vector used in the motion compensation of the current picture to be coded is stored, in the storage area, for use when a picture to be coded after the current picture to be coded is coded in direct mode; a step of coding the generated limitation information; a step of judging whether the current picture to be coded is a top field or a bottom field, in the case where the current picture to be coded is one of the fields of an interlaced picture, the fields being composed of the top field and the bottom field; and a step of (i) storing, into a top field storage area, the at least one motion vector used in motion compensation of the current picture to be coded, the top field storage area having a storage amount that is limited according to the limitation information, in the case where the current picture to be coded is judged to be the top field, and (ii) storing, into a bottom field storage area, the at least one motion vector used in motion compensation of the current picture to be coded, the bottom field storage area having a storage amount that is limited according to the limitation information, in the case where the current picture to be coded is judged to be the bottom field, wherein the top field storage area and the bottom field storage area are included in the storage area.