Image decoding apparatus and image coding apparatus
View Patent ↗An image decoding apparatus ( 31 ) includes a CT information decoding unit ( 10 ) configured, in each coding tree, to decode a constraint flag indicating whether or not to constrain decoding a prediction unit, and a CU decoding unit ( 20 ) configured, in the coding tree, to decode a prediction unit in a coding node to be decoded first and to not decode a prediction unit in another coding node, in a case that the constraint flag indicates constraint of decoding the prediction unit. According to the present invention, it is possible to reduce a coding amount of PU and complexity of coding/decoding an image while maintaining a split with a high degree of freedom by CT split (QT split and BT split).
1. An image decoding apparatus for decoding a picture, the image decoding apparatus comprising:
information decoding circuitry that
decodes a syntax element for specifying a prescribed size in a sequence parameter set, and
determines whether or not a size of a current coding unit is greater than the prescribed size, wherein:
the prescribed size is used for determining whether prediction information of the current coding unit is reused or not,
in a case that the size of the current coding unit is greater than the prescribed size, the information decoding circuitry derives prediction information as derived prediction information, and
otherwise, the information decoding circuitry does not derive prediction information and reuses the derived prediction information.
2. An image decoding method for decoding a picture, the image decoding method comprising:
decoding a syntax element for specifying a prescribed size in a sequence parameter set;
determining whether or not a size of a current coding unit is greater than the prescribed size;
in a case that the size of the current coding unit is greater than the prescribed size, deriving prediction information as derived prediction information; and
otherwise, not deriving prediction information and reusing the derived prediction information, wherein
the prescribed size is used for determining whether prediction information of the current coding unit is reused or not.
3. An image encoding apparatus for encoding a picture, the image encoding apparatus comprising:
information encoding circuitry that
encodes a syntax element for specifying a prescribed size in a sequence parameter set, and
determines whether or not a size of a current coding unit is greater than the prescribed size, wherein:
the prescribed size is used for determining whether prediction information of the current coding unit is reused or not,
in a case that the size of the current coding unit is greater than the prescribed size, the information encoding circuitry derives prediction information as derived prediction information, and
otherwise, the information encoding circuitry does not derive prediction information and reuses the derived prediction information.