Abstract: An image decoding method is provided which includes reconstructing an intra prediction mode group indicator and a prediction mode index of a current block, constructing a first group using valid intra prediction modes of left and top blocks, and determining the intra prediction mode corresponding to the prediction mode index and the intra prediction mode group indicator. Therefore, by causing the first group to include modes having a high possibility of being equal to the prediction mode of the current block on the basis of the valid intra prediction modes of the left and top blocks of the current block and determining the intra prediction mode group indicator and the prediction mode index to be encoded using the first group, it is possible to reduce an amount of information of the intra prediction mode to be encoded.

Abstract: An image decoding method is provided which includes reconstructing an intra prediction mode group indicator and a prediction mode index of a current block, constructing a first group using valid intra prediction modes of left and top blocks, and determining the intra prediction mode corresponding to the prediction mode index and the intra prediction mode group indicator. Therefore, by causing the first group to include modes having a high possibility of being equal to the prediction mode of the current block on the basis of the valid intra prediction modes of the left and top blocks of the current block and determining the intra prediction mode group indicator and the prediction mode index to be encoded using the first group, it is possible to reduce an amount of information of the intra prediction mode to be encoded.

Abstract: An image decoding method is provided which includes reconstructing an intra prediction mode group indicator and a prediction mode index of a current block, constructing a first group using valid intra prediction modes of left and top blocks, and determining the intra prediction mode corresponding to the prediction mode index and the intra prediction mode group indicator. Therefore, by causing the first group to include modes having a high possibility of being equal to the prediction mode of the current block on the basis of the valid intra prediction modes of the left and top blocks of the current block and determining the intra prediction mode group indicator and the prediction mode index to be encoded using the first group, it is possible to reduce an amount of information of the intra prediction mode to be encoded.

Abstract: An image decoding method is provided which includes reconstructing an intra prediction mode group indicator and a prediction mode index of a current block, constructing a first group using valid intra prediction modes of left and top blocks, and determining the intra prediction mode corresponding to the prediction mode index and the intra prediction mode group indicator. Therefore, by causing the first group to include modes having a high possibility of being equal to the prediction mode of the current block on the basis of the valid intra prediction modes of the left and top blocks of the current block and determining the intra prediction mode group indicator and the prediction mode index to be encoded using the first group, it is possible to reduce an amount of information of the intra prediction mode to be encoded.

Abstract: An image decoding device includes a processor, and a non-transitory computer-readable medium having stored thereon instructions that, when executed, cause the processor to perform a method that use quantization parameters of left and above coding units to derive a quantization parameter predictor used for generating a residual block.

Abstract: An image decoding device includes a processor, and a non-transitory computer-readable medium having stored thereon instructions that, when executed, cause the processor to perform a method that use quantization parameters of left and above coding units to derive a quantization parameter predictor used for generating a residual block.

Abstract: An image decoding device includes a processor, and a non-transitory computer-readable medium having stored thereon instructions that, when executed, cause the processor to perform a method that use quantization parameters of left and above coding units to derive a quantization parameter predictor used for generating a residual block.

Abstract: An image decoding device includes a processor, and a non-transitory computer-readable medium having stored thereon instructions that, when executed, cause the processor to perform a method that use quantization parameters of left and above coding units to derive a quantization parameter predictor used for generating a residual block.

Abstract: A method of decoding an intra prediction mode, can include reconstructing an intra prediction mode group indicator and a prediction mode index, constructing an MPM group including three intra prediction modes using valid intra prediction modes of left and top blocks of the current block, determining an intra prediction mode of the MPM group corresponding to the prediction mode index as the intra prediction mode of the current block when the intra prediction mode group indicator indicates that the intra prediction mode of the current block belongs to the MPM group and determining the intra prediction mode of the current block using the prediction mode index and the three intra prediction modes of the MPM group when the intra prediction mode group indicator indicates that the intra prediction mode of the current block does not belong to the MPM group.

Abstract: An image decoding device is provided which includes an intra prediction module for reconstructing an intra prediction mode and creating a prediction block of a current block or a sub block, an inverse scanning module for converting residual signals into a quantization block, an inverse quantization module for inversely quantizing the quantization block, and an inverse transform module for inversely-transforming the inversely-quantized block. A quantization parameter predictor for deriving the quantization parameter is created using quantization parameters of a left coding unit and a top coding unit of a current coding unit. Therefore, it is possible to improve image quality by adaptively adjusting a quantization parameter of a current block depending on the size of a coding unit and enhance compression efficiency of an image by effectively encoding/decoding the quantization parameter to reduce the number of bits required for transmitting the quantization parameter.

Abstract: A method of decoding an intra prediction mode, can include reconstructing an intra prediction mode group indicator and a prediction mode index, constructing an MPM group including three intra prediction modes using valid intra prediction modes of left and top blocks of the current block, determining an intra prediction mode of the MPM group corresponding to the prediction mode index as the intra prediction mode of the current block when the intra prediction mode group indicator indicates that the intra prediction mode of the current block belongs to the MPM group and determining the intra prediction mode of the current block using the prediction mode index and the three intra prediction modes of the MPM group when the intra prediction mode group indicator indicates that the intra prediction mode of the current block does not belong to the MPM group.

Abstract: An intra prediction mode decoding method includes reconstructing an intra prediction mode group indicator and a prediction mode index, constructing an MPM group including three intra prediction modes using valid intra prediction modes of left and top blocks of the current block, determining the intra prediction mode corresponding to the prediction mode index in the intra prediction group corresponding to the intra prediction mode group indicator, and assigning the lowest mode numbers to non-directional modes. Therefore, it is possible to reduce the amount of information for encoding the intra prediction mode of the current block by using intra prediction modes having higher possibility of being equal to the intra prediction mode of the current block. Also, it is possible to reduce the amount of information by assigning lowest mode numbers to the non-directional modes.

Abstract: An intra prediction mode decoding method includes reconstructing an intra prediction mode group indicator and a prediction mode index, constructing an MPM group including three intra prediction modes using valid intra prediction modes of left and top blocks of the current block, determining the intra prediction mode corresponding to the prediction mode index in the intra prediction group corresponding to the intra prediction mode group indicator, and assigning the lowest mode numbers to non-directional modes. Therefore, it is possible to reduce the amount of information for encoding the intra prediction mode of the current block by using intra prediction modes having higher possibility of being equal to the intra prediction mode of the current block. Also, it is possible to reduce the amount of information by assigning lowest mode numbers to the non-directional modes.

Abstract: A method for encoding an intra prediction mode according to the present invention selects an intra prediction mode for a current block, determines the number of valid MPM candidates by checking the validity of MPM candidates of the current block, and if the number of valid MPM candidates is less than a previously set number, adds additional intra prediction modes as MPM candidates. MPM candidates can be adaptively added on the basis of the directionality of valid MPM candidates. Additionally, during the encoding of residual intra prediction modes, residual intra prediction modes are realigned on the basis of the directionality of valid MPM candidates. Accordingly, the present invention minimizes the information for encoding the intra prediction mode of the current block by adding MPM candidates or realigning the residual intra prediction modes on the basis of the directionality of valid MPM candidates.

Abstract: An image decoding method is provided which includes reconstructing an intra prediction mode group indicator and a prediction mode index of a current block, constructing a first group using valid intra prediction modes of left and top blocks, and determining the intra prediction mode corresponding to the prediction mode index and the intra prediction mode group indicator. Therefore, by causing the first group to include modes having a high possibility of being equal to the prediction mode of the current block on the basis of the valid intra prediction modes of the left and top blocks of the current block and determining the intra prediction mode group indicator and the prediction mode index to be encoded using the first group, it is possible to reduce an amount of information of the intra prediction mode to be encoded.

Abstract: An image decoding method is provided which includes reconstructing an intra prediction mode group indicator and a prediction mode index of a current block, constructing a first group using valid intra prediction modes of left and top blocks, and determining the intra prediction mode corresponding to the prediction mode index and the intra prediction mode group indicator. Therefore, by causing the first group to include modes having a high possibility of being equal to the prediction mode of the current block on the basis of the valid intra prediction modes of the left and top blocks of the current block and determining the intra prediction mode group indicator and the prediction mode index to be encoded using the first group, it is possible to reduce an amount of information of the intra prediction mode to be encoded.

Abstract: An image decoding method is provided which includes reconstructing an intra prediction mode group indicator and a prediction mode index of a current block, constructing a first group using valid intra prediction modes of left and top blocks, and determining the intra prediction mode corresponding to the prediction mode index and the intra prediction mode group indicator. Therefore, by causing the first group to include modes having a high possibility of being equal to the prediction mode of the current block on the basis of the valid intra prediction modes of the left and top blocks of the current block and determining the intra prediction mode group indicator and the prediction mode index to be encoded using the first group, it is possible to reduce an amount of information of the intra prediction mode to be encoded.

Abstract: An image decoding method is provided which includes reconstructing an intra prediction mode group indicator and a prediction mode index of a current block, constructing a first group using valid intra prediction modes of left and top blocks, and determining the intra prediction mode corresponding to the prediction mode index and the intra prediction mode group indicator. Therefore, by causing the first group to include modes having a high possibility of being equal to the prediction mode of the current block on the basis of the valid intra prediction modes of the left and top blocks of the current block and determining the intra prediction mode group indicator and the prediction mode index to be encoded using the first group, it is possible to reduce an amount of information of the intra prediction mode to be encoded.

Abstract: A method for encoding an intra prediction mode according to the present invention selects an intra prediction mode for a current block, determines the number of valid MPM candidates by checking the validity of MPM candidates of the current block, and if the number of valid MPM candidates is less than a previously set number, adds additional intra prediction modes as MPM candidates. MPM candidates can be adaptively added on the basis of the directionality of valid MPM candidates. Additionally, during the encoding of residual intra prediction modes, residual intra prediction modes are realigned on the basis of the directionality of valid MPM candidates. Accordingly, the present invention allows the information for encoding the intra prediction mode of the current block to be minimized by adding MPM candidates or realigning the residual intra prediction modes on the basis of the directionality of valid MPM candidates.

Abstract: An intra prediction mode decoding method includes reconstructing an intra prediction mode group indicator and a prediction mode index, constructing an MPM group including three intra prediction modes using valid intra prediction modes of left and top blocks of the current block, determining the intra prediction mode corresponding to the prediction mode index in the intra prediction group corresponding to the intra prediction mode group indicator, and assigning the lowest mode numbers to non-directional modes. Therefore, it is possible to reduce the amount of information for encoding the intra prediction mode of the current block by using intra prediction modes having higher possibility of being equal to the intra prediction mode of the current block. Also, it is possible to reduce the amount of information by assigning lowest mode numbers to the non-directional modes.