IMAGE INTRA-PREDICTION MODE ESTIMATION DEVICE, IMAGE ENCODING DEVICE, IMAGE DECODING DEVICE, AND ENCODED IMAGE DATA THAT ADAPTIVELY DECIDES THE NUMBER OF ESTIMATED PREDICTION MODES TO BE ESTIMATED

摘要

A coding device and a decoding device are configured to include an estimated prediction mode deciding section (122a) including: a reference block selecting section (1223a) for selecting a reference block for use in estimating an intra-prediction mode for a subject block; an estimating number deciding section (1222a) for deciding an estimating number of estimated values to be estimated for the intra-prediction mode; and an estimated prediction mode deriving section (1221a) for estimating, based on a reference block, the estimating number of estimated values of the prediction mode.

主权项

1. A decoding device for decoding a coded data of a digital image constituted by a plurality of blocks, comprising:
a selecting circuit configured to select one or more adjacent blocks for a subject block, which is a subject for the decoding; a deriving circuit for deriving on the basis of a prediction mode(s) of the one or more adjacent blocks, an estimated prediction mode(s) to be estimated as an estimated value in intra-prediction mode estimation; a prediction mode decoding circuit for decoding, from the coded data, a prediction mode to be used in generation of a predicted image of the subject block, the prediction mode decoding circuit performing the decoding based on the estimated prediction mode(s) derived by the deriving circuit; and a predicted image generating circuit for generating a predicted image of the subject block, based on the prediction mode, the prediction mode decoding circuit decoding, for each of the plurality of blocks, a flag indicating whether or not an estimated prediction mode included in the group consisting of one or more estimated prediction modes for the block is identical with the prediction mode for the block, in a case where the flag is 1, the prediction mode decoding circuit designating the prediction mode of the subject block by (a) decoding an identifier mpm_idx and (b) referring to the identifier mpm_idx from among the one or more estimated prediction modes included in the group, and in a case where the flag is 0, the prediction mode decoding circuit designating the prediction mode of the subject block by (a′) decoding rem_bits and (b′) referring to the rem_bits from among prediction modes which are not included in the group.