Image decoding method, image coding method, image decoding apparatus, image coding apparatus, program, and integrated circuit

Abstract

An image coding method decodes a coded stream which is generated by inter prediction coding a moving picture and includes processing units and a header of such units, the processing units including at least one processing unit divided in a hierarchy, the hierarchy including: a highest hierarchical layer in which a coding unit is a largest processing unit; and a lower hierarchical layer in which a prediction unit exists. The method comprises: identifying, by parsing hierarchy depth information stored in the header and indicating a hierarchical layer higher than a lowest hierarchical layer in which a smallest prediction unit exits, a hierarchical layer which is indicated by the hierarchy depth information or a hierarchical layer higher than the indicated hierarchical layer, the hierarchical layer having a prediction unit that stores an adaptive motion vector resolution switch flag necessary for decoding; and decoding the prediction unit, using the flag.