| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem of intra-prediction mode encoding in which the same probability model is set to all blocks causing a low efficiency. <P>SOLUTION: A predicted direction difference calculation section 904 calculates a predicted direction difference of in-screen prediction modes of a plurality of reference blocks used for in-screen prediction of a decoding object block. A priority mode determination section 903 determines a priority prediction mode of the decoding object block on the basis of the in-screen prediction modes of the plurality of reference blocks used for calculating the predicted direction difference and the predicted direction difference. A decoding tree selection section 905 selects one decoding tree, in which a code string having a code length shorter than that of other prediction modes is allocated to the priority prediction mode, depending on the calculated predicted direction difference, from a plurality of decoding trees prepared depending on the predicted direction difference, to decode the in-screen prediction mode of the decoding object block. A variable-length decoding section 906 decodes the in-screen prediction mode of the decoding object block according to the selected decoding tree. <P>COPYRIGHT: (C)2013,JPO&INPIT |
