Abstract: Provided are an inter prediction method and a motion compensation method. The inter prediction method includes: performing inter prediction on a current image by using a long-term reference image stored in a decoded picture buffer; determining residual data and a motion vector of the current image generated via the inter prediction; and determining least significant bit (LSB) information as a long-term reference index indicating the long-term reference image by dividing picture order count (POC) information of the long-term reference image into most significant bit (MSB) information and the LSB information.

Abstract: Provided are a method and apparatus for determining quantization parameter for a quantization and an inverse quantization performed during a video encoding and decoding. The quantization parameter determination method includes determining transformation units of at least one size included in a coding unit; determining a default quantization parameter of the coding unit; reducing a quantization parameter of a transformation unit that is greater than a predetermined size, to be less than the default quantization parameter; and increasing a quantization parameter of a transformation unit that is less than a predetermined size, to be greater than the default quantization parameter.

Abstract: Provided are methods and apparatuses for encoding and decoding an image. The method of encoding includes: determining a maximum size of a buffer to decode each image frame by a decoder, a number of image frames to be reordered, and latency information of an image frame having a largest difference between an encoding order and a display order from among image frames that form an image sequence, based on an encoding order the image frames that form the image sequence, an encoding order of reference frames referred to by the image frames, a display order of the image frames, and a display order of the reference frames; and adding, to a mandatory sequence parameter set, a first syntax indicating the maximum size of the buffer, a second syntax indicating the number of image frames to be reordered, and a third syntax indicating the latency information.

Abstract: Provided are an image processing apparatus and an image processing method. The image processing method includes: obtaining a reference block a having a first resolution and a differential block having the first resolution; transforming a resolution of a prediction block having the first resolution and a resolution of the differential block having the first resolution in order to generate a prediction block having a second resolution and a differential block having the second resolution, the prediction block having the first resolution and the differential block having the first resolution being generated based on a pixel value of the reference block having the first resolution; and synthesizing the generated prediction block having the second resolution and the generated differential block having the second resolution in order to generate a target block having the second resolution.

Abstract: A method and apparatus for multiplexing and de-multiplexing video data. The method of multiplexing the video data involves syntax to a header of transmission unit data that is used to multiplex a clean random access (CRA) picture used in a random access, wherein the predetermined syntax indicates a reproduction status of the CRA picture, i.e., normal reproduction or reproduction according to a random access.

Abstract: Provided are a method and an apparatus for encoding and decoding motion information of a current prediction unit that is motion-predicted. The image encoding method includes: obtaining a first reference picture list, a second reference picture list, and a combination reference picture list which is a combination of reference pictures included in the first reference picture list and reference pictures included in the second reference picture list; and encoding a reference syntax indicating a motion prediction mode and a reference picture used in encoding a current prediction unit based on a number of possible cases of a unidirectional motion prediction mode and a number of possible cases of a bidirectional motion prediction mode.

Abstract: A method for estimating a boundary between a background and a user object in a video, in which the user object is segmented from the background is provided. The initial object contour is estimated in a first video frame for object segmentation, and color probability density functions are estimated for the user object and the background segmented from the first video frame. An edge strip with a predetermined width is generated in a current frame based on an object contour of a previous frame, and a coherence probability density function of the edge strip is estimated. The user object is segmented in the current frame by energy minimization.

Abstract: A method and apparatus for estimating the contour of a user object in a moving picture during video communications so that a personal background image is not provided during video communications. Information about center coordinates as well as a size of a face of the user object is extracted from a moving picture frame. Edges are extracted from the moving picture frame, and a boundary of a head of the user object is estimated using a semicircle. The boundaries of left and right shoulders and left and right arms of the user object are estimated using second-order function graphs that overlap a largest portion of the edges. An entire contour of the user object is estimated according to the boundaries of the head, the left and right shoulders, and the left and right arms of the user object.

Abstract: A method and apparatus for decoding video data that is encoded by bit rate control to keep a bandwidth of a bit stream in a predetermined range are provided. The encoded video data is decoded, picture quality estimation information is estimated, the estimation including information about a bit stream size of a decoded video frame, the number of fragmented macro blocks included in the video frame, and the number of skip-mode macro blocks included in the video frame, the picture quality of the video data is determined based on a correlation between picture quality estimation information and SNR, and the video data is output by applying a picture quality improving algorithm to the video data, if the determined picture quality is lower than a predetermined level.

Abstract: An apparatus for reproduction of an image frame in an image receiving system is disclosed. The apparatus includes a demultiplexer for restoring a received signal to a decodable bitstream and generating start information of each image frame of the bitstream, and an image decoder for decoding the bitstream restored by the demultiplexer, thereby generating a reproducible I frame or P frame, which is an image frame; an image reproduction time uniformity processing module for buffering each image frame output from the image decoder, and then outputting the buffered I frame or P frame while delaying the I frame or P frame based on the start information of each image frame provided by the demultiplexer according to a preset delay time. The present delay time has been preset to be greater than a processing time period required for decoding of an I frame and to be less than a time interval between image frames in the image bitstream.

Abstract: A method and apparatus for error concealment in decoding of a moving picture. The method includes the steps of determining an erroneous macro block in a present frame when the moving picture is decoded, finding a first macro block having a highest similarity to the erroneous macro block and a second macro block having a next highest similarity to the erroneous block in a previous frame by comparing adjacent pixels of respective blocks in the previous frame with adjacent pixels of the erroneous block in the present frame; and replacing the erroneous block by using an average between the found macro blocks having the highest similarity and the second highest similarity to thereby conceal the erroneous macro block. The apparatus includes a parser, an entropy decoder, an inverse quantizer, an inverse converter, and a concealment unit that uses motion compensation from a previous frame to correct a macro block in a current frame.

Abstract: A method and apparatus for reproducing data are provided. The method and apparatus involve receiving a first signal for marking a desired reproduction position in media data; storing reproduction information for reproducing the media data from the desired reproduction position without searching for reference data in the media data; and reproducing the media data by using the reproduction information if a second signal is received so as to request the media data to be reproduced from the desired reproduction position.

Abstract: An image intra prediction method and image intra prediction apparatus and a decoding apparatus and a decoding method using the image intra prediction method are provided. The image intra prediction method includes: backing up boundary pixel values adjacent to a block that is to be decoded; correcting the boundary pixel values adjacent to the block that is to be decoded based on correlations between the boundary pixels and pixels adjacent to the boundary pixels; predicting a block that is to be decoded according to an intra mode, from among a plurality of intra modes, based on the corrected boundary pixel values; and restoring the boundary pixel values from the backed-up values.

Abstract: Provided are an image processing apparatus and an image processing method. The image processing method includes: obtaining a reference block a having a first resolution and a differential block having the first resolution; transforming a resolution of a prediction block having the first resolution and a resolution of the differential block having the first resolution in order to generate a prediction block having a second resolution and a differential block having the second resolution, the prediction block having the first resolution and the differential block having the first resolution being generated based on a pixel value of the reference block having the first resolution; and synthesizing the generated prediction block having the second resolution and the generated differential block having the second resolution in order to generate a target block having the second resolution.

Abstract: Provided is a multichannel video reception apparatus of a mobile communication terminal for digital broadcasting. An RF processor receives a broadcast signal of a digital broadcast service via an antenna. A baseband processor processes the received broadcast signal in a baseband. A controller controls the RF processor and the baseband processor to receive the broadcast signal including video frames of a main channel and a sub-channel. A memory stores a program code, reference data, and updatable user data, for an operation of the controller. A video processor receives the video frames of the main channel and the sub-channel, decodes the latest key frame of the sub-channel if a key frame of the main channel occurs while decoding the video frames of the main channel, and after decoding the key frame of the sub-channel, decodes the frames of the main channel. A display divides the decoded video signal into a main-channel image and a sub-channel image and separately displays the images.

Abstract: Disclosed is a method for depacketization of multimedia packet data, the method comprising: a context-aware step of parsing and recording a start code, which can identify each frame, in a first portion of a payload of a real-time transport protocol (RTP) packet; and a step of performing depacketization according to each packet by using the start code.

Abstract: A terminal with a keypad enables a user to input an alphabet character through the keypad at high speed without modification of the keypad. The terminal comprises receiving a first input character in an alphabet input mode; waiting for a key input for at least one second input character succeeding the first input character; upon receiving a key input for the second input character, searching for a priority table in which a displaying order of a succeeding alphabet character is designated; and controlling a displaying order of the second input character according to the priority table.

Abstract: A method is provided for constructing a video frame in a video signal processing apparatus using multi-core processing, in which multiple macro blocks are generated from a video signal on a predetermined unit basis, and a video frame is constructed by combining the generated multiple macro blocks with header information. The video frame includes one correlation information field for recording information about correlations between the multiple macro blocks, and the one correlation information field is located in front of the multiple macro blocks constituting the video frame.

Abstract: A play-out apparatus and method for switching a channel in a digital multimedia broadcasting receiver are provided which can decrease a delay occurring in a channel switching time. A demultiplexer demultiplexes a signal received from a transmitter and outputs video data. A time stamp adapter changes a time stamp for indicating a play-out time of the video data such that the video data can be immediately output from a playback buffer without a Coder-Decoder (CODEC) delay, and outputs the video data including the changed time stamp. The playback buffer buffers and outputs the video data output from the time stamp adapter according to the changed time stamp. A video decoder decodes and outputs the video data output from the playback buffer according to the changed time stamp. A display unit plays the decoded video data out.

Abstract: A method and apparatus for estimating the contour of a user object in a moving picture during video communications so that a personal background image is not provided during video communications. Information about center coordinates as well as a size of a face of the user object is extracted from a moving picture frame. Edges are extracted from the moving picture frame, and a boundary of a head of the user object is estimated using a semicircle. The boundaries of left and right shoulders and left and right arms of the user object are estimated using second-order function graphs that overlap a largest portion of the edges. An entire contour of the user object is estimated according to the boundaries of the head, the left and right shoulders, and the left and right arms of the user object.