Abstract: Provided is a method derives a reference picture index and a motion vector of a current prediction unit, generates a prediction block of the current prediction unit using the reference picture index and the motion vector, generating a residual block by inverse-scan, inverse-quantization and inverse transform, and generates reconstructed pixels using the prediction block and the residual block. Prediction pixels of the prediction block is generated using an interpolation filter selected based on the motion vector. Accordingly, the coding efficiency of the motion information is improved by including various merge candidates. Also, the computational complexity of an encoder and a decoder is reduced by selecting different filter according to location of the prediction pixels determined by the motion vector.

Abstract: Provided is a method that derives an intra prediction mode of a prediction unit, selects an inverse scan pattern of a current transform unit among a diagonal scan, a vertical scan and a horizontal scan based on the intra prediction mode and a size of the transform unit, and generates a quantized block by inversely scanning significant flags, coefficients signs and coefficient levels according to the selected inverse scan pattern. If the transform unit is larger than a predetermined size, multiple subsets are generated and inversely scanned. Therefore, the amount of coding bits of the residual block is reduced by determining the scan pattern based on the size of the transform unit and the intra prediction mode, and by applying the scan pattern to each subset. Also, the signaling bits decreases by generating MPM group adaptively according to the neighboring intra prediction 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 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: Provided is a method derives a reference picture index and a motion vector of a current prediction unit, generates a prediction block of the current prediction unit using the reference picture index and the motion vector, generating a residual block by inverse-scan, inverse-quantization and inverse transform, and generates reconstructed pixels using the prediction block and the residual block. Prediction pixels of the prediction block is generated using an interpolation filter selected based on the motion vector. Accordingly, the coding efficiency of the motion information is improved by including various merge candidates. Also, the computational complexity of an encoder and a decoder is reduced by selecting different filter according to location of the prediction pixels determined by the motion vector.

Abstract: An apparatus is provided for decoding video data in a merge mode. The apparatus comprises an inter prediction unit configured to derive motion information of a current coding unit and generate a prediction block using the motion information, wherein the motion information is derived using a merge index and a merge candidate list constructed using available spatial and temporal merge candidates. The apparatus further comprises an inverse-quantizing unit configured to inverse-quantize a quantized block by using a quantization parameter, an inverse transform unit configured to generate a residual block by inverse-transforming the inverse-quantized block, and an adder configured to generate a reconstruct block by adding the residual block and the prediction block.

Abstract: An apparatus for post-processing a reconstructed image is discussed.

Abstract: A method is provided for deriving an intra prediction mode for a current prediction unit. The method includes entropy decoding a mode group indicator and a prediction mode index, constructing a most probable mode (MPM) group using intra prediction modes of a left block and an above block, wherein the MPM group includes three intra prediction modes, determining whether the mode group indicator indicates the MPM group, determining an intra prediction mode specified by the prediction mode index among the three intra prediction modes in the MPM group as the intra prediction mode of the current prediction unit when the mode group indicator indicates the MPM group, and deriving the intra prediction mode of the current prediction unit using the prediction mode index and the three intra prediction modes in the MPM group when the mode group indicator does not indicate the MPM group.

Abstract: An image encoding apparatus is presented. A differential quantization parameter is generated by subtracting a quantization parameter predictor from a quantization parameter, and is entropy-coded. If two or more quantization parameters are available among a left quantization parameter, an above quantization parameter and a previous quantization parameter of a current coding unit, the quantization parameter predictor is generated using two available quantization parameters determined according a predetermined order, and if only one quantization parameter is available, the available quantization parameter is set as the quantization parameter predictor. A transform type for inversely transforming the residual signals is selected among a discrete cosine transform (DCT)-based integer transform and a discrete sign transform (DST)-based integer transform based on a prediction mode and a size of a transform unit.

Abstract: The invention provides a method of decoding video data in merge mode, comprising: constructing a merge candidate list using available spatial and temporal merge candidates; deriving motion information using a merge index; generating a prediction block using the motion information; generating a residual block by inverse-quantizing the quantized block using a quantization parameter and by inverse-transforming the inverse quantized block; and generating a reconstructed block using the residual block and the prediction block, wherein the quantization parameter is generated per quantization unit and a minimum size of the quantization unit is adjusted per picture. Therefore, the coding efficiency of motion information by selecting predictor of motion information one among neighboring blocks and a temporal block.

Abstract: An apparatus is provided for encoding an image in an advanced motion vector prediction (AMVP) mode. The apparatus includes an inter prediction unit configured to determine motion information of a current block, and generating a prediction block of the current block using the motion information, a transform unit configured to transform the residual block to generated a transformed block, a quantization unit configured to quantize the transformed block using a quantization parameter and a quantization matrix to generate a quantized block, a scanning unit configured to for scan quantized coefficient components of the quantized block, and an entropy coding unit configured to perform entropy-coding on the scanned coefficient components of the quantized block. The quantization parameter is determined per a quantization unit and is encoded using a quantization parameter predictor. The quantization parameter predictor is generated by averaging two quantization parameters.

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: 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.

Abstract: A method for decoding an image is discussed. The method can include generating a residual block; reconstructing an intra prediction mode group indicator and a prediction mode index of a prediction unit; constructing a first group including three intra prediction modes using available intra prediction modes of left and top blocks of the prediction unit; determining the intra prediction mode corresponding to the prediction mode index in the first group as the intra prediction mode of the prediction unit when the intra prediction mode group indicator indicates the first group; generating a prediction block on the basis of the determined intra prediction mode of the prediction unit; generating a reconstructed block using the residual block and the prediction block; and performing deblocking filtering on a reconstructed picture.

Abstract: A method for decoding chroma image is discussed. The method includes deriving a chroma intra prediction mode of a prediction unit; determining a size of a current chroma block using luma transform size information; generating a chroma prediction block of the current chroma block using the chroma intra prediction mode; generating a chroma residual block of the current chroma block using the chroma intra prediction mode and a chroma quantization parameter; and generating a chroma reconstructed block adding the chroma prediction block and the chroma residual block.

Abstract: Provided is a method generates an edge index of a current sample, and applies an edge offset corresponding to the edge index to the current sample. The edge index is generated using the differences between a current sample and two neighboring samples determined by an edge offset type. Accordingly, the difference between original samples and reconstructed samples are effectively reduced by generating the optimum edge index. Also, the quantity of bits required for reducing the differences are reduced by fixing the sign of offset to positive or negative.

Abstract: A method of generating a reconstructed block is provided. A mode group indicator and a prediction mode index are entropy-decoded. A quantized block is inversely quantized using a quantization parameter and a quantization matrix to generate a transform block. The transform block is inversely transformed to generate a residual block. A Most Probable Mode (MPM) group including three intra prediction modes is constructed using a left intra prediction mode and an above intra prediction mode of a current prediction unit. An intra prediction mode of the current prediction unit is derived using the mode group indicator and the prediction mode index. Reference pixels of a current block are adaptively filtered according to a size of a transform unit and the intra prediction mode. The prediction block is generated according to the intra prediction mode. The reconstructed block is generated using the prediction block and the residual block.

Abstract: Provided is a method that derives an intra prediction mode of a prediction unit, determines a size of a current block using transform size information, generates a prediction block of the current block according to the intra prediction mode, generating a residual block of the current block according to the intra prediction mode and generating a reconstructed block of the current block using the prediction block and the residual block. The sizes of the prediction block and the residual block are set equal to a size of a transform unit. Therefore, the distance of intra prediction becomes short, and the amount of coding bits of residual block is reduced by generating a prediction block very similar to original block. Also, the signaling bits required to signal intra prediction mode decrease by generating MPM group adaptively according to the neighboring intra prediction modes.

Abstract: Provided is a method that derives an intra prediction mode of a prediction unit, determines a size of a current block using transform size information, generates a prediction block of the current block according to the intra prediction mode, generating a residual block of the current block according to the intra prediction mode and generating a reconstructed block of the current block using the prediction block and the residual block. The sizes of the prediction block and the residual block are set equal to a size of a transform unit. Therefore, the distance of intra prediction becomes short, and the amount of coding bits of residual block is reduced by generating a prediction block very similar to original block. Also, the signaling bits required to signal intra prediction mode decrease by generating MPM group adaptively according to the neighboring intra prediction modes.

Abstract: Provided is a method that derives an intra prediction mode of a prediction unit, determines a size of a current block using transform size information, generates a prediction block of the current block according to the intra prediction mode, generating a residual block of the current block according to the intra prediction mode and generating a reconstructed block of the current block using the prediction block and the residual block. The sizes of the prediction block and the residual block are set equal to a size of a transform unit. Therefore, the distance of intra prediction becomes short, and the amount of coding bits of residual block is reduced by generating a prediction block very similar to original block. Also, the signaling bits required to signal intra prediction mode decrease by generating MPM group adaptively according to the neighboring intra prediction modes.

Abstract: A method of post-processing a reconstructed image is discussed. The method according to an embodiment includes determining that a deblocking filtering process is performed per slice; when it is determined that the deblocking filtering process is performed, applying the deblocking filtering process to the slice; and applying an edge offset if a sample adaptive offset (SAO) type indicates an edge offset.