Moving picture coding device, moving picture coding method, and moving picture coding program, and moving picture decoding device, moving picture decoding method, and moving picture decoding program
In a moving picture coding device that further divides a first block acquired by dividing each picture of a moving picture into a predetermined size into one or a plurality of second blocks and codes the moving picture in units of blocks, a quantization parameter calculation unit calculates a quantization parameter of the second block. A predictive quantization parameter deriving unit derives a predictive quantization parameter of the second block by using the quantization parameter of one or a plurality of third blocks that are neighboring to the second block. The predictive quantization parameter deriving unit derives the predictive quantization parameter of the second block by using a quantization parameter of a fourth block coded before the second block in a case where the third block neighboring to the second block is located at a position beyond a boundary of the first block.
1. A moving picture decoding device that decodes a bitstream in which moving pictures are coded by partitioning a first block, which is obtained by partitioning each picture of the moving pictures into predetermined sizes, into one or a plurality of second blocks, the device comprising:
a decoding unit configured to extract size information of a block to derive a predictive quantization parameter and extract a differential quantization parameter of the second block by decoding the bitstream;
a predictive quantization parameter deriving unit configured to derive a predictive quantization parameter of the second block using quantization parameters of a third block adjacent to the left of the second block and a fourth block adjacent to the top of the second block; and
a quantization parameter generation unit configured to generate a quantization parameter of the second block by adding the differential quantization parameter of the second block and the predictive quantization parameter of the second block, wherein
(a) when the size of the second block is equal to or larger than the size specified in the extracted size information to derive a predictive quantization parameter or the second block is a block located at a left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter, the predictive quantization parameter deriving unit sets the quantization parameter of the third block as a first quantization parameter when the third block is at a position not beyond a boundary of the first block, sets a quantization parameter of a fifth block decoded immediately before the second block in a decoding order as the first quantization parameter when the third block is at a position beyond the boundary of the first block so as to set the first quantization parameter having a non-zero value regardless of the position for the boundary of the first block, sets the quantization parameter of the fourth block as a second quantization parameter when the fourth block is at a position not beyond the boundary of the first block, sets the quantization parameter of the fifth block as the second quantization parameter when the fourth block is at a position beyond the boundary of the first block so as to set the second quantization parameter having a non-zero value regardless of the position for the boundary of the first block, and derives an average of the first and second quantization parameters as the predictive quantization parameter of the second block regardless of the position of the third block or the fourth block, or both the third and fourth blocks, with respect to the boundary of the first block, and wherein
(b) when the size of the second block is smaller than the size specified in the extracted size information to derive a predictive quantization parameter and the second block is a block other than the block located at the left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter, the predictive quantization parameter deriving unit uses as the predictive quantization parameter of the second block the predictive quantization parameter derived in the block located at the left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter that includes the second block.
2. A moving picture decoding method of decoding a bitstream in which moving pictures are coded by partitioning a first block, which is obtained by partitioning each picture of the moving pictures into predetermined sizes, into one or a plurality of second blocks, the method comprising:
a decoding step of extracting size information of a block to derive a predictive quantization parameter and extracting a differential quantization parameter of the second block by decoding the bitstream;
a predictive quantization parameter deriving step of deriving a predictive quantization parameter of the second block using quantization parameters of a third block adjacent to the left of the second block and a fourth block adjacent to the top of the second block; and
a quantization parameter generation step of generating a quantization parameter of the second block by adding the differential quantization parameter of the second block and the predictive quantization parameter of the second block, wherein
(a) when the size of the second block is equal to or larger than the size specified in the extracted size information to derive a predictive quantization parameter or the second block is a block located at a left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter, the predictive quantization parameter deriving step sets the quantization parameter of the third block as a first quantization parameter when the third block is at a position not beyond a boundary of the first block, sets a quantization parameter of a fifth block decoded immediately before the second block in a decoding order as the first quantization parameter when the third block is at a position beyond the boundary of the first block so as to set the first quantization parameter having a non-zero value regardless of the position for the boundary of the first block, sets the quantization parameter of the fourth block as a second quantization parameter when the fourth block is at a position not beyond the boundary of the first block, sets the quantization parameter of the fifth block as the second quantization parameter when the fourth block is at a position beyond the boundary of the first block so as to set the second quantization parameter having a non-zero value regardless of the position for the boundary of the first block, and derives an average of the first and second quantization parameters as the predictive quantization parameter of the second block regardless of the position of the third block or the fourth block, or both the third and fourth blocks, with respect to the boundary of the first block, and wherein
(b) when the size of the second block is smaller than the size specified in the extracted size information to derive a predictive quantization parameter and the second block is a block other than the block located at the left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter, the predictive quantization parameter deriving step uses as the predictive quantization parameter of the second block the predictive quantization parameter derived in the block located at the left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter that includes the second block.
3. A non-transitory recording medium having a moving picture decoding program for decoding a bitstream in which moving pictures are coded by partitioning a first block, which is obtained by partitioning each picture of the moving pictures into predetermined sizes, into one or a plurality of second blocks, the program causing a computer to execute:
a decoding step of extracting size information of a block to derive a predictive quantization parameter and extracting a differential quantization parameter of the second block by decoding the bitstream;
a predictive quantization parameter deriving step of deriving a predictive quantization parameter of the second block using quantization parameters of a third block adjacent to the left of the second block and a fourth block adjacent to the top of the second block; and
a quantization parameter generation step of generating a quantization parameter of the second block by adding the differential quantization parameter of the second block and the predictive quantization parameter of the second block, wherein
(a) when the size of the second block is equal to or larger than the size specified in the extracted size information to derive a predictive quantization parameter or the second block is a block located at a left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter, the predictive quantization parameter deriving step sets the quantization parameter of the third block as a first quantization parameter when the third block is at a position not beyond a boundary of the first block, sets a quantization parameter of a fifth block decoded immediately before the second block in a decoding order as the first quantization parameter when the third block is at a position beyond the boundary of the first block so as to set the first quantization parameter having a non-zero value regardless of the position for the boundary of the first block, sets the quantization parameter of the fourth block as a second quantization parameter when the fourth block is at a position not beyond the boundary of the first block, sets the quantization parameter of the fifth block as the second quantization parameter when the fourth block is at a position beyond the boundary of the first block so as to set the second quantization parameter having a non-zero value regardless of the position for the boundary of the first block, and derives an average of the first and second quantization parameters as the predictive quantization parameter of the second block regardless of the position of the third block or the fourth block, or both the third and fourth blocks, with respect to the boundary of the first block, and wherein
(b) when the size of the second block is smaller than the size specified in the extracted size information to derive a predictive quantization parameter and the second block is a block other than the block located at the left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter, the predictive quantization parameter deriving step uses as the predictive quantization parameter of the second block the predictive quantization parameter derived in the block located at the left top corner within the block of the size specified in the extracted size information to derive a predictive quantization parameter that includes the second block.