Picture decoding device, picture decoding method, picture decoding program, receiving device, receiving method, and receiving program

Abstract

In a case where a partition mode in which luma signals are partitioned horizontally and vertically is set when an intra prediction of a picture signal is made in units of minimal coding blocks set in advance, an intra prediction unit is configured to make an intra prediction of a chroma signal in units of prediction blocks of the intra prediction of chroma signals within the minimal coding block set in accordance with a chroma format. A second bitstream constructing unit constructs a bitstream of information relating to a luma intra prediction mode of a prediction block of luma signals and information relating to a chroma intra prediction mode of a prediction block of chroma signals.

What is claimed is: 
     
         1 . A picture decoding device that decodes information relating to an intra prediction mode and performs intra prediction decoding of a picture signal including a luma signal and a chroma signal in units of blocks, the picture decoding device comprising:
 a bitstream decoding unit configured to decode information relating to the prediction mode of the coding block and decode a syntax element relating to a luma intra prediction mode of the first prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the second prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the third prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the fourth prediction block of luma signals, and subsequently decode a syntax element relating to a chroma intra prediction mode of the prediction block of chroma signals that is located at a reference position that is the same as the position of the first prediction block of luma signals from a bitstream in which coding information relating to the intra prediction modes is arranged within the coding block and accordingly acquire the luma intra prediction modes of the first to fourth prediction blocks of luma signals and the chroma intra prediction mode of the prediction block of chroma signals, in a case where a partition mode in which a coding block of luma signals is partitioned horizontally and vertically is derived;   a luma signal intra prediction unit that, in a case where the partition mode is set, is configured to set the first to fourth prediction blocks of luma signals acquired by partitioning luma signals of the coding block horizontally and vertically and predict a luma signal based on a decoded neighboring block of luma signals in accordance with each of the luma intra prediction mode;   a chroma signal intra prediction unit configured to set the prediction block of chroma signals without partitioning chroma signals of the coding block and predict a chroma signal based on a decoded neighboring block of chroma signals in accordance with a chroma intra prediction mode in a case where the partition mode is set,   wherein the chroma signal intra prediction unit is configured to set a value indicating the chroma intra prediction mode of the prediction block of chroma signals within the coding block to be equal to a value indicating the luma intra prediction mode of the first prediction block of luma signals within the coding block, in a mode of setting the chroma intra prediction mode depending on the luma intra prediction mode,   wherein the chroma signal intra prediction unit is configured to set a value indicating vertical prediction in which a prediction direction is a vertical direction as one of predefined values of the chroma intra prediction mode of the prediction block of the chroma signals, when the chroma intra prediction mode is not set in accordance with the luma intra prediction mode,   wherein the bitstream decoding unit, the luma signal intra prediction unit, and the chroma signal intra prediction unit are implemented using hardware, memory storing firmware, or a computer with software.   
     
     
         2 . A picture decoding method for decoding information relating to an intra prediction mode and performing intra prediction decoding of a picture signal including a luma signal and a chroma signal in units of blocks, the picture decoding method comprising:
 a bitstream decoding step of decoding information relating to the prediction mode of the coding block and decoding a syntax element relating to a luma intra prediction mode of the first prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the second prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the third prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the fourth prediction block of luma signals, and subsequently decoding a syntax element relating to a chroma intra prediction mode of the prediction block of chroma signals that is located at a reference position that is the same as the position of the first prediction block of luma signals from a bitstream in which coding information relating to the intra prediction modes is arranged within the coding block and accordingly acquiring the luma intra prediction modes of the first to fourth prediction blocks of luma signals and the chroma intra prediction mode of the prediction block of chroma signals, in a case where a partition mode in which a coding block of luma signals is partitioned horizontally and vertically is derived;   a luma signal intra prediction step of, in a case where the partition mode is set, setting the first to fourth prediction blocks of luma signals acquired by partitioning luma signals of the coding block horizontally and vertically and predicting a luma signal based on a decoded neighboring block of luma signals in accordance with each of the luma intra prediction mode;   a chroma signal intra prediction step of setting the prediction block of chroma signals without partitioning chroma signals of the coding block and predicting a chroma signal based on a decoded neighboring block of chroma signals in accordance with a chroma intra prediction mode in a case where the partition mode is set,   wherein the chroma signal intra prediction step sets a value indicating the chroma intra prediction mode of the prediction block of chroma signals within the coding block to be equal to a value indicating the luma intra prediction mode of the first prediction block of luma signals within the coding block, in a mode of setting the chroma intra prediction mode depending on the luma intra prediction mode,   wherein the chroma signal intra prediction step sets a value indicating vertical prediction in which a prediction direction is a vertical direction as one of predefined values of the chroma intra prediction mode of the prediction block of the chroma signals, when the chroma intra prediction mode is not set in accordance with the luma intra prediction mode,   wherein the bitstream decoding step, the luma signal intra prediction step, and the chroma signal intra prediction step are performed using hardware, memory storing firmware, or a computer with software.   
     
     
         3 . A non-transitory recording medium on which a picture decoding program for decoding information relating to an intra prediction mode and performing intra prediction decoding of a picture signal including a luma signal and a chroma signal in units of blocks is stored, the picture decoding program causing a computer to execute:
 a bitstream decoding step of decoding information relating to the prediction mode of the coding block and decoding a syntax element relating to a luma intra prediction mode of the first prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the second prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the third prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the fourth prediction block of luma signals, and subsequently decoding a syntax element relating to a chroma intra prediction mode of the prediction block of chroma signals that is located at a reference position that is the same as the position of the first prediction block of luma signals from a bitstream in which coding information relating to the intra prediction modes is arranged within the coding block and accordingly acquiring the luma intra prediction modes of the first to fourth prediction blocks of luma signals and the chroma intra prediction mode of the prediction block of chroma signals, in a case where a partition mode in which a coding block of luma signals is partitioned horizontally and vertically is derived;   a luma signal intra prediction step of, in a case where the partition mode is set, setting the first to fourth prediction blocks of luma signals acquired by partitioning luma signals of the coding block horizontally and vertically and predicting a luma signal based on a decoded neighboring block of luma signals in accordance with each of the luma intra prediction mode;   a chroma signal intra prediction step of setting the prediction block of chroma signals without partitioning chroma signals of the coding block and predicting a chroma signal based on a decoded neighboring block of chroma signals in accordance with a chroma intra prediction mode in a case where the partition mode is set,   wherein the chroma signal intra prediction step sets a value indicating the chroma intra prediction mode of the prediction block of chroma signals within the coding block to be equal to a value indicating the luma intra prediction mode of the first prediction block of luma signals within the coding block, in a mode of setting the chroma intra prediction mode depending on the luma intra prediction mode,   wherein the chroma signal intra prediction step sets a value indicating vertical prediction in which a prediction direction is a vertical direction as one of predefined values of the chroma intra prediction mode of the prediction block of the chroma signals, when the chroma intra prediction mode is not set in accordance with the luma intra prediction mode.   
     
     
         4 . A receiving device that performs intra prediction decoding of a picture signal including a luma signal and a chroma signal in units of blocks by receiving a bitstream in which a picture is coded and decoding information relating to an intra prediction mode, the receiving device comprising:
 a receiving unit configured to receive a bitstream in which the bitstream acquired by coding a picture is packetized;   a restoration unit configured to restore the original bitstream by performing a packet process of the received packetized stream;   a bitstream decoding unit configured to decode information relating to the prediction mode of the coding block and decode a syntax element relating to a luma intra prediction mode of the first prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the second prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the third prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the fourth prediction block of luma signals, and subsequently decode a syntax element relating to a chroma intra prediction mode of the prediction block of chroma signals that is located at a reference position that is the same as the position of the first prediction block of luma signals from a bitstream in which coding information relating to the intra prediction modes is arranged within the coding block and accordingly acquire the luma intra prediction modes of the first to fourth prediction blocks of luma signals and the chroma intra prediction mode of the prediction block of chroma signals, in a case where a partition mode in which a coding block of luma signals is partitioned horizontally and vertically is derived;   a luma signal intra prediction unit that, in a case where the partition mode is set, is configured to set the first to fourth prediction blocks of luma signals acquired by partitioning luma signals of the coding block horizontally and vertically and predict a luma signal based on a decoded neighboring block of luma signals in accordance with each of the luma intra prediction mode;   a chroma signal intra prediction unit configured to set the prediction block of chroma signals without partitioning chroma signals of the coding block and predict a chroma signal based on a decoded neighboring block of chroma signals in accordance with a chroma intra prediction mode in a case where the partition mode is set,   wherein the chroma signal intra prediction unit is configured to set a value indicating the chroma intra prediction mode of the prediction block of chroma signals within the coding block to be equal to a value indicating the luma intra prediction mode of the first prediction block of luma signals within the coding block, in a mode of setting the chroma intra prediction mode depending on the luma intra prediction mode,   wherein the chroma signal intra prediction unit is configured to set a value indicating vertical prediction in which a prediction direction is a vertical direction as one of predefined values of the chroma intra prediction mode of the prediction block of the chroma signals, when the chroma intra prediction mode is not set in accordance with the luma intra prediction mode,   wherein the receiving unit, the restoration unit, the bitstream decoding unit, the luma signal intra prediction unit, and the chroma signal intra prediction unit are implemented using hardware, memory storing firmware, or a computer with software.   
     
     
         5 . A receiving method for performing intra prediction decoding of a picture signal including a luma signal and a chroma signal in units of blocks by receiving a bitstream in which a picture is coded and decoding information relating to an intra prediction mode, the receiving device comprising:
 a receiving step of receiving a bitstream in which the bitstream acquired by coding a picture is packetized;   a restoration step of restoring the original bitstream by performing a packet process of the received packetized stream;   a bitstream decoding step of decoding information relating to the prediction mode of the coding block and decoding a syntax element relating to a luma intra prediction mode of the first prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the second prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the third prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the fourth prediction block of luma signals, and subsequently decoding a syntax element relating to a chroma intra prediction mode of the prediction block of chroma signals that is located at a reference position that is the same as the position of the first prediction block of luma signals from a bitstream in which coding information relating to the intra prediction modes is arranged within the coding block and accordingly acquiring the luma intra prediction modes of the first to fourth prediction blocks of luma signals and the chroma intra prediction mode of the prediction block of chroma signals, in a case where a partition mode in which a coding block of luma signals is partitioned horizontally and vertically is derived;   a luma signal intra prediction step of, in a case where the partition mode is set, setting the first to fourth prediction blocks of luma signals acquired by partitioning luma signals of the coding block horizontally and vertically and predicting a luma signal based on a decoded neighboring block of luma signals in accordance with each of the luma intra prediction mode;   a chroma signal intra prediction step of setting the prediction block of chroma signals without partitioning chroma signals of the coding block and predicting a chroma signal based on a decoded neighboring block of chroma signals in accordance with a chroma intra prediction mode in a case where the partition mode is set,   wherein the chroma signal intra prediction step sets a value indicating the chroma intra prediction mode of the prediction block of chroma signals within the coding block to be equal to a value indicating the luma intra prediction mode of the first prediction block of luma signals within the coding block, in a mode of setting the chroma intra prediction mode depending on the luma intra prediction mode,   wherein the chroma signal intra prediction step sets a value indicating vertical prediction in which a prediction direction is a vertical direction as one of predefined values of the chroma intra prediction mode of the prediction block of the chroma signals, when the chroma intra prediction mode is not set in accordance with the luma intra prediction mode,   wherein the receiving step, the restoration step, the bitstream decoding step, the luma signal intra prediction step, and the chroma signal intra prediction step are performed using hardware, memory storing firmware, or a computer with software.   
     
     
         6 . A non-transitory recording medium on which a receiving program for performing intra prediction decoding of a picture signal including a luma signal and a chroma signal in units of blocks by receiving a bitstream in which a picture is coded and decoding information relating to an intra prediction mode, the receiving program causing a computer to execute:
 a receiving step of receiving a bitstream in which the bitstream acquired by coding a picture is packetized;   a restoration step of restoring the original bitstream by performing a packet process of the received packetized stream;   a bitstream decoding step of decoding information relating to the prediction mode of the coding block and decoding a syntax element relating to a luma intra prediction mode of the first prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the second prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the third prediction block of luma signals, a syntax element relating to a luma intra prediction mode of the fourth prediction block of luma signals, and subsequently decoding a syntax element relating to a chroma intra prediction mode of the prediction block of chroma signals that is located at a reference position that is the same as the position of the first prediction block of luma signals from a bitstream in which coding information relating to the intra prediction modes is arranged within the coding block and accordingly acquiring the luma intra prediction modes of the first to fourth prediction blocks of luma signals and the chroma intra prediction mode of the prediction block of chroma signals, in a case where a partition mode in which a coding block of luma signals is partitioned horizontally and vertically is derived;   a luma signal intra prediction step of, in a case where the partition mode is set, setting the first to fourth prediction blocks of luma signals acquired by partitioning luma signals of the coding block horizontally and vertically and predicting a luma signal based on a decoded neighboring block of luma signals in accordance with each of the luma intra prediction mode;   a chroma signal intra prediction step of setting the prediction block of chroma signals without partitioning chroma signals of the coding block and predicting a chroma signal based on a decoded neighboring block of chroma signals in accordance with a chroma intra prediction mode in a case where the partition mode is set,   wherein the chroma signal intra prediction step sets a value indicating the chroma intra prediction mode of the prediction block of chroma signals within the coding block to be equal to a value indicating the luma intra prediction mode of the first prediction block of luma signals within the coding block, in a mode of setting the chroma intra prediction mode depending on the luma intra prediction mode,   wherein the chroma signal intra prediction step sets a value indicating vertical prediction in which a prediction direction is a vertical direction as one of predefined values of the chroma intra prediction mode of the prediction block of the chroma signals, when the chroma intra prediction mode is not set in accordance with the luma intra prediction mode.