Patent ID: 8270492

Claim:
A moving picture decoding device for decoding a plurality of pictures constituting a moving image, the moving picture decoding device comprising: a mode extracting unit which extracts, as an extracted encoding mode, an encoding mode for each target block of the plurality of pictures; a reference judgment unit which, when a target block of one picture of the plurality of pictures is decoded in the extracted encoding mode and the extracted encoding mode is a first encoding mode, judges whether or not a reference picture, for a decoded picture which is in a vicinity of the one picture of the plurality of pictures in terms of a display time, is usable, the first encoding mode requiring the target block of the one picture to be decoded using the reference picture and a reference motion vector for the decoded picture; a decoding unit which (i) decodes the target block of the one picture using the reference picture for the decoded picture and in the first encoding mode, when the reference judgment unit judges that the reference picture is usable, and (ii) decodes the target block of the one picture in a mode different from the first encoding mode requiring the target block of the one picture to be decoded using the reference picture, when the reference judgment unit judges that the reference picture is not usable; and a picture storage unit which stores a decoded picture each time a picture of the plurality of pictures is decoded by the decoding unit, wherein each picture of the plurality of pictures includes a reference picture list identifying one or more pictures of the plurality of pictures that can be referred to when decoding is performed in the first encoding mode, and wherein the reference judgment unit judges that the reference picture is usable when the reference picture is stored in the picture storage unit, regardless of whether or not the reference picture is identified by the reference picture list of the one picture of the plurality of pictures as a picture that can be referred to when the decoding is performed in the first encoding mode.