Video coding apparatus and video coding method

Abstract

A video coding apparatus including a dividing part that outputs the coding target picture divided for each coding unit (basic CU); a prediction processor that generates a prediction image by performing one of intra prediction and inter-screen prediction; a difference calculator that generates a difference image by calculating a difference between the generated prediction image and an image corresponding to the prediction image in the coding target picture; a residual coder that generates a residual coefficient by performing transform processing and quantization processing on the generated difference image; an integration unit that integrates a plurality of basic CUs included in an N×N-pixel region into one new CU, and a code string generator that generates a code string corresponding to the post-integration new CU by performing variable-length coding and arithmetic coding on coding information and the residual coefficient.

1 - 12 . (canceled) 
     
     
         13 . A video coding apparatus that codes a current picture to generate a code string, the video coding apparatus comprising:
 a block practitioner which, in operation, divides the current picture into a plurality of blocks, the plurality of blocks including a first block and a second block;   a residual coder which, in operation, generates a residual coefficient by calculating a difference between a prediction image which is generated for each of the plurality of blocks and the current picture; and   a code string generator which, in operation, generates the code string based on the residual coefficient, wherein:   the code string generator provides a common header information to both the first block and the second block, when a prediction information of the first block is the same as a prediction information of the second block, and   the code string generator provides a prediction information of the first block as a header information of the first block to the first block and provides a prediction information of the second block as a header information of the second block to the second block, when the prediction information of the first block is different from the prediction information of the second block.   
     
     
         14 . A decoding method for decoding an image, on a block-by-block basis, from a coded stream, the decoding method comprising:
 determining, for a first block, whether a common prediction information or a block prediction information is used for generating a prediction image for the first block;   generating, when the first block is included in a group unit that is bigger than the first block, a prediction image corresponding to the first block using the common prediction information, the group unit including at least the first block and a second block, the common prediction information being used for all blocks included in the group unit;   generating, when the first block is not included in the group unit, a prediction image corresponding to the first block using the block prediction information included in the first block; and   generating a decoded image corresponding to the first block using the prediction image and a residual coefficient, the residual coefficient being included in the first block regardless of whether or not the first block is included in the group unit.   
     
     
         15 . A decoding apparatus for decoding an image, on a block-by-block basis, from a coded stream, the decoding apparatus comprising:
 a processor; and   a non-transitory memory having stored thereon executable instructions, which when executed, cause the processor to perform:   reading a first information corresponding to a quantization parameter, the first information being used for a plurality of blocks included in a picture;   determining, using a second information of a current picture including a current block and a third information of the current block included in the current picture, whether or not a fourth information corresponding to a quantization parameter of a current unit is used for the current block, the second information being an information on a picture-by-picture basis and the third information not being an information on a picture-by-picture basis; and   decoding, when the fourth information is determined to be used for the current block, the current block by using the first information and the fourth information,   wherein the fourth information is used for all of a plurality of blocks included in the current unit.