Abstract: A method can include decoding residual signals to generate quantized coefficient components; determining an inverse scan pattern and generating a quantized block using the inverse scan pattern; deriving a quantization parameter and inversely quantizing the quantized block using the quantization parameter to generate a transformed block; and inversely transforming the transformed block to generate a residual block, in which when the quantization parameter is a chroma quantization parameter, the chroma quantization parameter is generated using a luma quantization parameter and an offset parameter indicating a relationship between the luma quantization parameter and the chroma quantization parameter, the luma quantization parameter is derived using a differential quantization parameter and a quantization parameter predictor, and the differential quantization parameter is generated by entropy decoding, and parameters are set according to certain conditions.

Abstract: An image coding method can include generating a prediction block using an intra prediction mode; generating a prediction block using motion information; transforming residual signals generated using an original block and the prediction block to generate a transformed block; quantizing the transformed block using a quantization parameter to generate a quantized block; determining a scan pattern and applying the scan pattern to the quantized block to generate one-dimensional coefficient information; and entropy-coding the one-dimensional coefficient information, in which the residual signals are transformed in transform unit, a transform type used for transforming the residual signals of luma component is determined by a prediction mode and a size of the transform unit, and a transform type used for transforming the residual signals of chroma components is a DCT-based integer transform, and the quantization parameter is a luma quantization parameter, and a differential quantization parameter is generated by sub

Abstract: An image decoding apparatus can include a prediction mode decoding module for deriving luma intra prediction mode and chroma intra prediction mode; a prediction size determining module for determining a size of a luma transform unit and a size of a chroma transform unit; a reference pixel generating module for generating a reference pixel when at least one reference pixel is unavailable; a reference pixel filtering module for adaptively filtering a reference pixel of a current luma block based on the luma intra prediction mode and the size of the luma transform unit, wherein a reference pixel of a current chroma block is not filtered; a prediction block generating module for generating prediction blocks of the current luma block and the current chroma block; and a residual block generating module for generating a luma residual block and a chroma residual block.

Abstract: An apparatus can include a prediction mode decoding module configured to derive a luma intra prediction mode and a chroma intra prediction mode; a prediction size determining module configured to determine a size of a luma transform unit and a size of a chroma transform unit using transform size information; a reference pixel generating module configured to generate referential pixels if at least one reference pixel is unavailable; a reference pixel filtering module configured to adaptively filter the reference pixels of a current luma block based on the luma intra prediction mode and the size of the luma transform unit, and not to filter the reference pixels of a current chroma block; a prediction block generating module configured to generate prediction blocks of the current luma block and the current chroma block; a residual bock generating module configured to generate a luma residual block and a chroma residual block; and an adder.

Abstract: An apparatus for decoding an image can include an inverse scanning module for generating a quantized block by applying an inverse scan pattern to significant flags, coefficient sign and coefficient levels respectively; an inverse quantization module for generating a quantization parameter predictor, adding the quantization parameter predictor to a differential quantization parameter to generate a quantization parameter and inversely quantizing the quantized block using the quantization parameter; an inverse transform module for inversely transforming the inversely quantized block to restore a residual block; an intra prediction module for generating a prediction block; an adder for generating a reconstructed block using the residual block and the prediction block, in which certain types of scans are used based on a size of a transform unit and various parameters are set according to availability conditions.

Abstract: Provided is a method that de-multiplexes a bit stream to extract intra prediction mode information and residual signals, restores an intra prediction mode of a current prediction unit using the intra prediction information and intra prediction modes of prediction units adjacent to the current prediction unit, generates reference pixels using one or more available reference pixel if there exist unavailable reference pixels of the prediction unit, adaptively filters the reference pixels based on the restored intra prediction mode, generates a prediction block using the restored intra prediction mode and the reference pixels, decodes the residual signal to generating a residual block, and generates a reconstructed block using the prediction block and the residual block. Accordingly, additional bits resulted from increase of a number of intra prediction mode are effectively reduced. Also, an image compression ratio can be improved by generating a prediction block similar to an original block.

Abstract: Provided is an apparatus for decoding an image. The apparatus restores a plurality of sub-blocks by applying a scan pattern determined according to the intra prediction mode of the current block on the quantization coefficient sequence and restores the quantized transform block by applying a scan pattern determined according to the intra prediction mode of the current block on the plurality of sub-blocks. Therefore, it is possible to reduce the amount of coding bits and computing resources required to decode a current prediction block.

Abstract: Provided is a method that de-multiplexes a bit stream to extract intra prediction mode information and residual signals, restores an intra prediction mode of a current prediction unit using the intra prediction information and intra prediction modes of prediction units adjacent to the current prediction unit, generates reference pixels using one or more available reference pixel if there exist unavailable reference pixels of the prediction unit, adaptively filters the reference pixels based on the restored intra prediction mode, generates a prediction block using the restored intra prediction mode and the reference pixels, decodes the residual signal to generating a residual block, and generates a reconstructed block using the prediction block and the residual block. Accordingly, additional bits resulted from increase of a number of intra prediction mode are effectively reduced. Also, an image compression ratio can be improved by generating a prediction block similar to an original block.

Abstract: An image decoding method can include deriving luma intra prediction mode and chroma intra prediction mode, wherein the luma intra prediction mode is derived by using a prediction mode index, a mode group indicator, and an MPM (Most Probable Mode) group including three intra prediction modes; determining a size of a luma transform unit and a size of a chroma transform unit; generating a reference pixel when at least one of reference pixels is unavailable; adaptively filtering a reference pixel of a current luma block based on the luma intra prediction mode and the size of luma transform unit; generating prediction blocks of a current chroma block and the current luma block using the adaptively filtered reference pixel; generating residual blocks of the current chroma block and the current luma block; and generating a reconstructed block by adding the residual blocks and the prediction blocks.

Abstract: An apparatus for decoding an image in intra prediction can include an inverse scanning module generating a quantized block by applying an inverse scan pattern to significant flags, coefficient signs and coefficient levels; an inverse quantization module generating a quantization parameter predictor, adding the quantization parameter predictor to a differential quantization parameter to generate a quantization parameter and inversely quantizing the quantized block using the quantization parameter; an inverse transform module inversely transforming the inversely quantized block to restore a residual block; an intra prediction module generating a prediction block; and an adder generating a reconstructed block using the residual block and the prediction block, in which when a size of a transform unit is equal to or smaller than 8×8, the inverse scan pattern is a horizontal scan for a vertical mode and a predetermined number of intra prediction modes having closest direction to the vertical mode, the inverse scan

Abstract: Provided is an apparatus for decoding an image. The apparatus restores a plurality of sub-blocks by applying a scan pattern determined according to the intra prediction mode of the current block on the quantization coefficient sequence and restores the quantized transform block by applying a scan pattern determined according to the intra prediction mode of the current block on the plurality of sub-blocks. Therefore, it is possible to reduce the amount of coding bits and computing resources required to decode a current prediction block.

Abstract: A method of reconstructing video data using a merge mode can include constructing a merge list using available spatial and temporal merge candidates; determining a merge candidate on the merge list corresponding to a merge index as motion information of a current prediction unit; generating a predicted block of the current prediction unit using the motion information; generating a transformed block by inverse-quantizing a block of quantized coefficients using a quantization parameter; generating a residual block by inverse-transforming the transformed block; and generating a reconstructed block using the predicted block and the residual block, in which when the current prediction unit is a second prediction unit partitioned by asymmetric partitioning, the spatial merge candidate corresponding to a first prediction unit partitioned by the asymmetric partitioning is excluded from the merge list, and a motion vector of the temporal merge candidate is determined depending on a position of the current prediction u

Abstract: A method for decoding an image in intra prediction, includes generating two-dimensional quantized block by applying an inverse scan pattern to significant coefficients, sign flags and levels respectively; generating a quantization parameter predictor; adding the quantization parameter predictor and a differential quantization parameter to generate quantization parameter; inversely quantizing the quantized block using the quantization parameter; inversely transforming the inversely quantized block to restore a residual block; generating a prediction block; and generating a reconstructed block using the residual block and the prediction block.

Abstract: An image decoding method includes deriving an intra prediction mode using three intra prediction modes which are determined by left and above intra prediction modes of a current prediction unit; generating a prediction block according to the intra prediction mode; generating a residual block using the intra prediction mode; and generating a reconstructed block using the prediction block and the residual block, wherein the intra prediction mode is derived by constructing a Most Probable Mode (MPM) group including three intra prediction modes determined based on the left intra prediction mode and the above intra prediction mode, by setting an intra prediction mode of the MPM group specified by a prediction mode index as the intra prediction mode of the current prediction unit if a mode group indicator indicates the MPM group, and by determining the intra prediction mode of the current prediction unit if the mode group indicator does not indicate the MPM group.

Abstract: A method for decoding chroma image can include deriving a chroma intra prediction mode of a prediction unit using a corresponding luma intra prediction mode; determining a size of a current chroma block using luma transform size information; generating a chroma prediction block of the current chroma block; 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, in which the chroma quantization parameter is generated using a luma quantization parameter determined per quantization unit and information indicating the relationship between the luma quantization parameter and the chroma quantization parameter, the size of the quantization unit is one of allowable sizes of a coding unit, and a minimum size of the quantization unit is determined per picture and a parameter for specifying the minimum size of the quantization uni

Abstract: A method of decoding video data in uni-directional prediction by a decoding apparatus can include deriving, by the decoding apparatus, a reference picture index and a motion vector of a current prediction unit; generating, by the decoding apparatus, a prediction block of the current prediction unit using the reference picture index and the motion vector; generating, by the decoding apparatus, a quantized block by inversely scanning quantized coefficient components; generating, by the decoding apparatus, a transformed block by inversely quantizing the quantized block using a quantization parameter; generating, by the decoding apparatus, a residual block by inversely transforming the transformed block; and generating, by the decoding apparatus, reconstructed pixels using the prediction block and the residual block, in which prediction pixels of the prediction block are generated using an interpolation filter selected based on the motion vector, the interpolation filter being a 7-tap filter if the motion vector

Abstract: A method of encoding an image in an advanced motion vector prediction (AMVP) mode can include determining motion information of a current block, and generating a prediction block of the current block using the motion information; transforming the residual block to generate a transformed block; quantizing the transformed block using a quantization parameter and a quantization matrix to generate a quantized block; scanning quantized coefficient components of the quantized block; and entropy-coding the scanned coefficient components of the quantized block, in which the motion information is encoded by performing the sub-steps of constructing an AMVP list using available motion vector candidates of a left motion vector candidate, an above motion vector candidate and a temporal motion vector candidate; selecting a motion vector predictor among motion vector candidates of the AMVP candidate list; and generating a differential motion vector by subtracting the motion vector predictor from the motion vector.

Abstract: A method for generating a prediction block in intra prediction, includes restoring a mode group indicator and a prediction mode index; constructing a most probable mode (MPM) group including three intra prediction modes of a current block; determining an intra prediction mode specified by the intra prediction mode index in the MPM group as the intra prediction mode of the current block if the mode group indicator indicates the MPM group, and deriving the intra prediction mode of the current block using the prediction mode index and the three intra prediction modes of the MPM group if the mode group indicator does not indicate the MPM group; determining a size of the prediction block based on transform size information; determining whether all reference pixels of the current block are available; generating reference pixels if one or more reference pixels of the current block are unavailable; adaptively filtering the reference pixels based on the intra prediction mode and the size of the current block; and gene

Abstract: A method of decoding video data using quantized coefficient components and inter prediction information can include extracting quantized coefficient components and inter prediction information from a received bit stream; applying an inverse scan pattern to the quantized coefficient components to generate a quantized block having a size of a transform unit; generating a quantization parameter per quantization unit which is a unit for deriving a quantization parameter and inverse-quantizing the quantized block to generate a transformed block; generating a residual block by inverse-transforming the transformed block; deriving motion information and generating a prediction block; and generating a reconstructed block by using the residual block and the prediction block.

Abstract: Provided is an image decoding apparatus that restores a quantized transform block by inversely scanning 1D quantized coefficients, inversely quantizes the quantized transform block using a quantization step size, inversely transforms the transform block to generate a residual block, and generates a prediction block according to an intra prediction mode. When a size of the transform block is 8×8, the quantized transform block is divided into a plurality of sub-blocks, and the plurality of sub-blocks and coefficients of each sub-block are scanned using a same scan pattern determined according to the intra prediction mode. When the intra prediction mode is a horizontal mode, the scan pattern is a vertical scan.