Patent ID: 8379726
Filing Date: 2013-02-19
Classification: H04N

Abstract:
1. A coding apparatus that applies coding to an image signal in a prediction mode and in units of an image area which conform to a predetermined coding scheme, and outputs the coded image signal, comprising: storage means for storing information used for coding an image area to be currently coded in a direct prediction mode that predicts motion information of an image area to be coded by referring to motion information of a previously coded image area; deriving means for deriving motion information of the image area in the direct prediction mode by referring to the information stored in the storage means; selecting means for selecting a prediction mode for coding the image area to be coded, in accordance with the motion information derived by the deriving means; setting means for setting a constraint of using, as the direct prediction mode, a prediction mode that derives motion information of the image area to be coded only by referring to, within a picture in which the image area to be coded is located, motion information of an image area to which the coding has been applied; and determining means for determining whether or not one or more pieces of information is necessary for the deriving means to derive motion information of an image area to which the coding has not been applied, from coding information applied in the prediction mode selected by the selecting means to the image area to be coded, in accordance with the constraint set by the setting means, and storing only information that is determined to be necessary to derive motion information, into the storage means, wherein the necessary information being stored comprises information as to whether or not the value of an anchor motion vector is ±1 or less, but excludes the specific value of the anchor motion vector.