Patent ID: 8265150

Claim:
A picture decoding apparatus which decodes, on a block-by-block basis, a picture that is coded and included in a coded signal, the picture decoding apparatus comprising: a variable length decoding unit configured to: decode a frame weighting factor that is coded and included in the coded signal, and to generate a field weighting factor from the decoded frame weighting factor, in the case where the picture has a frame structure and is coded such that switching between frame coding and field coding of a block included in the picture is adaptively performed; decode a frame weighting factor that is coded and included in the coded signal, in the case where the picture has a frame structure and is coded such that frame coding is performed on all blocks included in the picture; and decode a field weighting factor that is coded and included in the coded signal, in the case where the picture has a field structure and is coded such that field coding is performed on all blocks included in the picture; a motion compensation unit configured to: generate a predictive image by scaling pixel values of a reference frame to which the block refers using the decoded frame weighting factor, in the case where the picture has a frame structure and is coded such that switching between frame coding and field coding of a block included in the picture is adaptively performed and the block included in the picture is frame coded, and to generate a predictive image by scaling pixel values of a reference field to which the block refers using the generated field weighting factor, in the case where the picture has a frame structure and is coded such that switching between frame coding and field coding of a block included in the picture is adaptively performed and the block is field coded; generate a predictive image by scaling pixel values of a reference frame to which the block refers using the decoded frame weighting factor, in the case where all blocks included in the picture is frame coded; and generate a predictive image by scaling pixel values of a reference field to which the block refers using the decoded field weighting factor, in the case where all blocks included in the picture is field coded; and an adding unit configured to reconstruct the picture using the generated predictive image.