Abstract: A video decoding apparatus using an intra prediction, includes: a decoder to decode a bitstream to thereby extract residual signals; an inverse quantizer to inversely quantize the residual signals; an inverse transformer to inversely transform the inversely quantized residual signals; an intra predictor to predict a current block from a plurality of neighboring blocks of the current block; and an adder to add the inversely transformed residual signals to the predicted pixels in the predicted block, wherein the intra predictor includes a weighted pixel calculator to calculate a plurality of weighted pixel values of pixels selected in the neighboring blocks by applying weights to the pixels selected in the neighboring blocks, the weights being decided variably based on a position of a current pixel to be predicted in the current block; and a pixel predictor to derive a predicted pixel value of the current pixel using the weighted pixel values.

Abstract: A method for decoding a residual block, includes: obtaining residual data from encoded data; identifying one or more conditions for enabling an inverse quantization and an inverse transform; skipping both of the inverse quantization and the inverse transform for the obtained residual data to thereby reconstruct a residual block directly from the obtained residual data, when the one or more identified conditions indicate skipping of both the inverse quantization and the inverse transform; inversely quantizing the obtained residual data and skipping the inverse transform for the inversely quantized residual data to thereby reconstruct a residual block using the inverse-quantized residual data, when the one or more identified conditions indicate skipping of the inverse transform; and inversely quantizing the obtained residual data and inversely transforming the inversely quantized residual data to thereby reconstruct a residual block using the inverse transformed residual data.

Abstract: The present disclosure relates to an apparatus and method for encoding/decoding videos using prediction direction change and selective encoding. The present disclosure provides a video encoding apparatus that encodes the current block of a video, comprising a rectangle encoder for dividing and then successively encoding the current block at input into rectangular block units to output a rectangularly encoded bitstream; a square encoder for encoding the current block at input in square block units to output a squarely encoded bitstream; and an encoding selector for calculating the encoding costs of the rectangularly encoded bitstream and the squarely encoded bitstream so as to output the bitstream with a minimum encoding cost. According to the present disclosure, the prediction accuracy may be increased when encoding or decoding videos so that video encoding efficiency can be improved.

Abstract: An apparatus for decoding a current motion vector of a current block in a current frame from a bitstream, includes: a differential motion vector decoder to reconstruct a differential motion vector by decoding an encoded differential motion vector included in the bitstream; and a motion vector reconstructor to select one or more motion vector prediction candidates to predict the current motion vector, determine a predicted motion vector among the one or more motion vector prediction candidates, and reconstruct the current motion vector of the current block by adding the predicted motion vector to the differential motion vector.

Abstract: An image encoding and decoding method comprising: a coefficient calculator for calculating adaptive interpolation filter coefficient of a current frame; an image encoder for interpolating reference frames using the adaptive interpolation filter coefficient of the current frame and encoding the current frame using the interpolated reference frames; a filter flag encoder for generating and encoding a coefficient-inserted flag or coefficient non-inserted flag as a filter flag according to the adaptive interpolation filter coefficient of the current frame; a coefficient encoder for encoding the adaptive interpolation filter coefficient of the current frame when the filter flag is a coefficient-inserted flag; and a bit stream generator for generating and outputting a bit stream, which includes the encoded current frame and encoded filter flag, and further includes encoded adaptive interpolation filter coefficient of the current frame when the filter flag is the coefficient-inserted flag.

Abstract: The present disclosure relates to an intra prediction method and apparatus and an image encoding/decoding method and apparatus using the same. The disclosure provides the intra prediction apparatus that predicts the pixel values of respective pixels in a current block by weight-averaging the pixel values of one or more adjacent pixels in neighboring blocks to the current block according to the distances between each pixel in the current block and the adjacent pixel(s). According to the disclosure, the current block to be encoded can be predicted more accurately so that the encoding efficiency is improved by reducing the difference between the original block and the predicted block, and thereby video compression efficiency can be improved.

Abstract: A method and an apparatus for encoding a motion vector, and a method and an apparatus for encoding/decoding an image using the same are disclosed. The apparatus includes: a prediction candidate selector for selecting one or more motion vector prediction candidates; a predicted motion vector determiner for determining a PMV among the one or more motion vector prediction candidates; and a differential motion vector encoder for calculating a differential motion vector encoder for calculating a DMV by subtracting the predicted motion vector having been determined, from the current motion vector, and encoding the d having been calculated. The apparatus encodes a motion vector by using the prediction motion vector which is more accurately predicted, and reduces an amount of bits required for encoding information of the predicted motion vector, thereby improving the compression efficiency.

Abstract: An image encoding/decoding method and apparatus using coefficients of an adaptive interpolation filter are disclosed including: a coefficient calculator for calculating adaptive interpolation filter coefficient of a current frame; an image encoder for interpolating reference frames using the adaptive interpolation filter coefficient of the current frame and encoding the current frame using the interpolated reference frames; a filter flag encoder for generating and encoding a coefficient-inserted flag or coefficient non-inserted flag as a filter flag according to the adaptive interpolation filter coefficient of the current frame; a coefficient encoder for encoding the adaptive interpolation filter coefficient of the current frame when the filter flag is a coefficient-inserted flag; and a bit stream generator for generating and outputting a bit stream, which includes the encoded current frame and encoded filter flag, and further includes encoded adaptive interpolation filter coefficient of the current frame whe

Abstract: A method and an apparatus for image encoding/decoding are disclosed. The apparatus includes: a block decomposer for decomposing a current block into a plurality of sub-blocks; and an intra prediction encoder for performing an intra prediction encoding by referring to already encoded and decoded adjacent pixel information of each sub-block, based on an intra prediction mode equal to an intra prediction mode of the current block, thereby generating a bit stream for the current block. In image encoding and image decoding, when a current block to be encoded or decoded is predicted, the disclosed method and apparatus can improve the accuracy of the prediction, which can provide an image with a satisfactory reproduction quality by improved coding efficiency.

Abstract: The present disclosure relates to a method and an apparatus for motion vector encoding/decoding through estimations of multiple motion vectors, and to a method and an apparatus for video encoding/decoding using the same. The disclosure provides a motion vector encoding apparatus including a motion vector estimator for estimating a plurality of motion vectors with estimating one of the plurality of motion vectors as a motion vector of a current block and estimating the remaining motion vectors by one or more predefined estimation criteria in agreement with a video decoding apparatus; and a motion information encoder for encoding motion information generated by using the plurality of motion vectors. According to the disclosure, estimations are enabled by using more accurate motion vectors while reducing the bit rate for encoding the motion vectors leading to an improvement of the compressing efficiency.

Abstract: The present disclosure relates to a video encoding/decoding apparatus, and apparatus and method for adaptive overlapped block motion compensation by variable units for same. The apparatus and the method for adaptive overlapped block motion compensation by variable units, according to the present disclosure, when conducting a motion compensation, enable an encoder to perform an adaptive overlapped block motion compensation for a plurality of predetermined scan modes and sampling modes, and enable the encoder to calculate the computation volume occurring in said compensation and residual pixel energy, estimate the performance for each mode based on the calculation, determine an optimum scan mode and an optimum sampling mode, thus enabling a decoder to perform a motion compensation with optimum performance and less computing volume based on the determined mode.

Abstract: The present disclosure relates to a method and an apparatus for encoding/decoding a color image or video. The video encoding apparatus encodes a luminance component block for a current block of an image, performs a selection of a color format among a plurality of color formats to encode a chrominance component block for the current block of the image according to the color format upon selection, and generates and outputs a bitstream including the encoded luminance component block, the encoded chrominance component block, and information on the selected color format. The disclosure enables an improvement in compression performance by allowing encoding and decoding one video component image in various color formats.

Abstract: A method and an apparatus for image encoding/decoding are disclosed. The apparatus includes: a block decomposer for decomposing a current block into a plurality of sub-blocks; and an intra prediction encoder for performing an intra prediction encoding by referring to already encoded and decoded adjacent pixel information of each sub-block, based on an intra prediction mode equal to an intra prediction mode of the current block, thereby generating a bit stream for the current block. In image encoding and image decoding, when a current block to be encoded or decoded is predicted, the disclosed method and apparatus can improve the accuracy of the prediction, which can provide an image with a satisfactory reproduction quality by improved coding efficiency.

Abstract: The present disclosure relates to a method and an apparatus for motion vector encoding/decoding through estimations of multiple motion vectors, and to a method and an apparatus for video encoding/decoding using the same. The disclosure provides a motion vector encoding apparatus including a motion vector estimator for estimating a plurality of motion vectors with estimating one of the plurality of motion vectors as a motion vector of a current block and estimating the remaining motion vectors by one or more predefined estimation criteria in agreement with a video decoding apparatus; and a motion information encoder for encoding motion information generated by using the plurality of motion vectors. According to the disclosure, estimations are enabled by using more accurate motion vectors while reducing the bit rate for encoding the motion vectors leading to an improvement of the compressing efficiency.

Abstract: The present disclosure relates to method and apparatus for block mode encoding/decoding and a method and apparatus for video encoding/decoding using the same. The disclosure provides a block mode encoding apparatus that predicts the block mode of a current block and encodes the block mode of the current block depending on whether the block mode of the current block is same as the block mode predicted, to output encoded mode information. The disclosure can reduce the quantity of bits used to encode information on the block mode, thus enhancing the efficiency of video compression.

Abstract: An apparatus and a method for video encoding/decoding using predictability of an intra-prediction mode are disclosed. The apparatus for encoding a video of the present disclosure includes: an intra-prediction mode determiner for determining an encoder prediction mode which is an intra-prediction mode of a current block of the video; an encoder for encoding a residual block generated by subtracting, from the current block, a predicted block generated by predicting the current block according to the encoder prediction mode; a mode information generator for generating mode information according to whether or not a video decoding apparatus is able to predict the encoder prediction mode; and an encoded data generator for generating encoded data including the encoded residual block and the mode information. The present disclosure can enhance compression in video encoding/decoding by using intra-prediction to predict the video with a minimum necessary bit rate.

Abstract: An apparatus and a method for video encoding/decoding using predictability of an intra-prediction mode are disclosed. The apparatus for encoding a video of the present disclosure includes: an intra-prediction mode determiner for determining an encoder prediction mode which is an intra-prediction mode of a current block of the video; an encoder for encoding a residual block generated by subtracting, from the current block, a predicted block generated by predicting the current block according to the encoder prediction mode; a mode information generator for generating mode information according to whether or not a video decoding apparatus is able to predict the encoder prediction mode; and an encoded data generator for generating encoded data including the encoded residual block and the mode information. The present disclosure can enhance compression in video encoding/decoding by using intra-prediction to predict the video with a minimum necessary bit rate.

Abstract: The present disclosure relates to an apparatus and method for determining an adaptive filter tap to encode a wavelet transform coefficient, a wavelet transform apparatus and a method using the same, and a recording medium for the same, wherein the filter tap is determined rendering the high-band energy to be minimized, based not only on whether an edge is present but also on the edge location so as to adaptively determine the filter tap for an efficient coding of the wavelet transform coefficient. Therefore, the disclosure is able to prevent ringing artifacts and increase coding efficiency while maintaining clear definition on the edges.

Abstract: The present disclosure relates to an intra prediction method and apparatus and an image encoding/decoding method and apparatus using the same. The disclosure provides the intra prediction apparatus that predicts the pixel values of respective pixels in a current block by weight-averaging the pixel values of one or more adjacent pixels in neighboring blocks to the current block according to the distances between each pixel in the current block and the adjacent pixel(s). According to the disclosure, the current block to be encoded can be predicted more accurately so that the encoding efficiency is improved by reducing the difference between the original block and the predicted block, and thereby video compression efficiency can be improved.

Abstract: The present disclosure relates to a wavelet transform apparatus and method based on a prediction-update lifting scheme, and an adaptive prediction apparatus and method and a recording medium for the same. The disclosure comprises the steps of: setting first updated even polyphase samples influenced when being updated from corresponding odd polyphase samples, setting plural candidate groups for prediction direction based on the set first updated even polyphase samples, selecting a first prediction direction from the candidate groups to minimize the energy in a high band, obtaining a first prediction value based on the first prediction direction and the updated even polyphase samples corresponding to the first prediction direction, and obtaining residual odd polyphase samples by deducting the first prediction value from the corresponding odd polyphase samples.