Abstract: An apparatus of post-processing a reconstructed image is discussed. The apparatus according to an embodiment includes a deblocking filter for determining a boundary strength for each 4-sample edge which is a prediction edge or a transform edge and lies on 8×8 sample grid, determining whether deblocking filtering is applied on the 4-sample edge or not using the boundary strength and a boundary quantization parameter, and filtering the 4-sample edge if the deblocking filtering is applied on the 4-sample edge; and a sample adaptive offset adder for, if a sample adaptive offset type indicates an edge offset, generating an edge index of a current sample, generating an edge offset corresponding to the edge index to the current sample, and adding the edge offset to the current sample.

Abstract: Provided is a method of post-processing a reconstructed image. The method according to an embodiment includes determining a boundary strength for each 4-sample edge which is a prediction edge or a transform edge and lies on 8×8 sample grid, determining whether deblocking filtering is applied on the 4-sample edge or not using the boundary strength and a boundary quantization parameter, filtering the 4-sample edge if the deblocking filtering is applied on the 4-sample edge, and applying an edge offset if a sample adaptive offset (SAO) type indicates an edge offset.

Abstract: A method is provided for decoding an image. An advanced motion vector prediction (AMVP) candidate list is constructed using available motion vector candidates of a left motion vector candidate, an above motion vector candidate and a temporal motion vector candidate. A motion vector predictor is selected among motion vector candidates of the AMVP candidate list using an AMVP index. A motion vector is generated using the motion vector predictor and a differential motion vector. A prediction block is generated using the motion vector and a reference picture index. A quantized block is inversely quantized using a quantization parameter to generate a transformed block and inversely transform the transformed block to generate a residual block. A reconstructed block is generated using the prediction block and the residual block.

Abstract: Provided is a method that derives a chroma intra prediction mode of a prediction unit, determines a size of a current chroma block using luma transform size information, generates a chroma prediction block of the current chroma block using the chroma intra prediction mode, generates a chroma residual block of the current chroma block using the chroma intra prediction mode and a chroma quantization parameter, generates a chroma reconstructed block adding the chroma prediction block and the chroma residual block, and the chroma quantization parameter is generated using a luma quantization parameter and information indicating the relationship between the luma quantization parameter and the chroma quantization parameter. Therefore, the coding efficiency is improved by adjusting the chroma quantization parameter per picture. Also, the amount of bits for transmitting the luma and chroma quantization parameters is reduced by encoding the luma quantization parameter using neighboring luma quantization parameters.

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 coding apparatus according to an embodiment includes an intra prediction unit configured to generate a prediction block using an intra prediction mode; an inter prediction unit configured to generate a prediction block using motion information; a transform unit configured to transform residual signals generated an original block and the prediction block to generate a transformed block; a quantization unit configured to quantize the transformed block using a quantization parameter to generate a quantized block; a scanning unit configured to determine a scan pattern and applying the scan pattern to the quantized block to generate one-dimensional coefficient information; and an entropy coding unit configured to entropy-code the one-dimensional coefficient information.

Abstract: An apparatus for generating a residual block according to an embodiment includes an entropy decoding unit configured to decode residual signals to generate quantized coefficient components; an inverse scanning unit configured to determine an inverse scan pattern and generate a quantized block using the inverse scan pattern; an inverse quantization unit configured to derive a quantization parameter and inversely quantize the quantized block using the quantization parameter to generate a transformed block; and an inverse transform unit configured to inversely transform the transformed block to generate a residual block.

Abstract: A method is provided of decoding video data using a merge mode. A merge list is constructed using available spatial and temporal merge candidates. A merge candidate on the merge list corresponding to a merge index is determined as motion information of a current prediction unit. A predicted block of the current prediction unit is generated using the motion information. A transformed block is generated by inverse-quantizing a block of quantized coefficients using a quantization parameter. A residual block is generated by inverse-transforming the transformed block. A reconstructed block is generated using the predicted block and the residual block.

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 using a merge mode can include constructing a merge candidate list using available spatial and temporal merge candidates, obtaining motion information using a merge index and the merge candidate list, deriving a prediction block using the motion information, inverse-quantizing a quantized block using a quantization parameter and a quantization matrix to generate a transform block, and inverse-transforming the transform block to generate a residual block, and generating a reconstructed block using the prediction block and the residual block.

Abstract: An image decoding method in a merge mode, can include constructing a merge candidate list using available spatial and temporal merge candidates, and deriving motion information using a merge index and the merge candidate list; generating a prediction block using the motion information; generating a quantization block by inverse-scanning quantized coefficient components according to a diagonal scan, inverse-quantizing the quantization block using a quantization parameter and a quantization matrix, and inverse transforming the inversely-quantized quantization block to generate a residual block; and deriving a reconstructed block using the prediction block and the residual block.

Abstract: Provided is a method that derives a chroma intra prediction mode of a prediction unit, determines a size of a current chroma block using luma transform size information, generates a chroma prediction block of the current chroma block using the chroma intra prediction mode, generates a chroma residual block of the current chroma block using the chroma intra prediction mode and a chroma quantization parameter, generates a chroma reconstructed block adding the chroma prediction block and the chroma residual block, and the chroma quantization parameter is generated using a luma quantization parameter and information indicating the relationship between the luma quantization parameter and the chroma quantization parameter. Therefore, the coding efficiency is improved by adjusting the chroma quantization parameter per picture. Also, the amount of bits for transmitting the luma and chroma quantization parameters is reduced by encoding the luma quantization parameter using neighboring luma quantization parameters.

Abstract: Provided is a method that derives a chroma intra prediction mode of a prediction unit, determines a size of a current chroma block using luma transform size information, generates a chroma prediction block of the current chroma block using the chroma intra prediction mode, generates a chroma residual block of the current chroma block using the chroma intra prediciton mode and a chroma quantization parameter, generates a chroma reconstructed block adding the chroma prediction block and the chroma residual block, and the chroma quantization parameter is generated using a luma quantization parameter and information indicating the relationship between the luma quantization parameter and the chroma quantization parameter. Therefore, the coding efficiency is improved by adjusting the chroma quantization parameter per picture. Also, the amount of bits for transmitting the luma and chroma quantization parameters is reduced by encoding the luma quantization parameter using neighboring luma quantization parameters.

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: Provided is an apparatus that derives a luma intra prediction mode and a chroma intra prediction mode, determines a size of a luma transform unit and a size of a chroma transform unit using luma transform size information, adaptively filters the reference pixels of a current luma block based on the luma intra prediction mode and the size of the luma transform unit, generates prediction blocks of the current luma block and the current chroma block and generates a residual luma residual block and a chroma residual block. Therefore, the distance of intra prediction becomes short, and the amount of coding bits required to encode intra prediction modes and residual blocks of luma and chroma components is reduced and the coding complexity is reduced by adaptively encoding the intra prediction modes and adaptively filtering the reference pixels.

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 is provided for decoding video data in a merge mode. A quantized block is generated by inverse-scanning quantized coefficient components. A transformed block is generated by inverse-quantizing the quantized block using a quantization parameter. A residual block is generated by inverse-transforming the transformed block. A merge list is constructed using available spatial and temporal merge candidates. A merge candidate is set on the merge list specified by a merge index as motion information of a current prediction unit. A prediction block of the current prediction unit is generated using the motion information. A reconstructed block is generated using the prediction block and the residual block.