| 摘要 |
PROBLEM TO BE SOLVED: To provide an image decoding device that selects and uses a conversion base corresponding to a prediction mode.SOLUTION: An image decoding device includes a decoding unit 402, a setting unit 411, a conversion unit 405, and an adding unit 406. The decoding unit decodes a conversion coefficient to be decoded from accumulated decoding data. The setting unit sets the combination of a vertical conversion matrix and a horizontal conversion matrix corresponding to the prediction mode on the basis of a predetermined relationship according to a prediction image creation method. The conversion unit uses the set conversion matrix to perform vertical conversion and horizontal conversion to the conversion coefficient and obtains a prediction error. The adding unit creates a decoded image on the basis of the prediction error. The combination is either one of the combination of first conversion matrices or the combination of second conversion matrices different from the first conversion matrix. The combination of second conversion matrices is set in a plurality of intra-prediction modes each corresponding to diagonal lower right prediction, vertical right prediction, and horizontal lower prediction. |
