Abstract: In an image down-sampling transcoding method, by reducing an MPEG SP (simple profile) video bit stream having a CIF (Common Intermediate Format) size into a half in image size in a pixel domain, the video bit stream is converted into a H.264 BP (Baseline Profile) video stream having a QCIF (Quarter CIF) size. Accordingly, it is possible to down-sample an image from MPEG-4 to H.264 at a high speed.

Abstract: A method of encoding multi-view video using camera parameters and a method of decoding multi-view video using the camera parameters are provided. The method of encoding multi-view video using the camera parameters includes detecting the camera parameters from each of a plurality of video data input from a multi-view camera in predetermined video units, and adaptively encoding each of the plurality of the video data according to whether each video data has the camera parameters. Accordingly, it is possible to increase the efficiency of compressing video without degrading video quality.

Abstract: Methods and devices are provided for down-sampling an image from H.264 to MPEG-4 at a high speed. The method for converting a first macro block having a first format into a second macro block having a second format includes: (a) determining a block mode of the second macro block and converting the first macro block into the second macro block with the determined block mode, when the number of intra macro blocks included in the first macro block satisfies a first condition; (b) determining a block mode of the second macro block and converting the first macro block into the second macro block with the determined block mode, when the number for inter macro blocks included in the first macro block satisfies a second condition; and (c) re-adjusting a motion vector of the second macro block, after the conversion of the first macro block into the second macro block is finished.

Abstract: Provided are a motion estimation device and method adaptive to change in illumination. The motion estimation method includes the steps of: generating a current frame pattern block and a reference frame pattern block for a reference frame block; calculating the sum of absolute differences (SAD) for candidate pattern blocks and determining the candidate pattern block corresponding to the SAD satisfying a predetermined condition among the calculated SAD as a motion vector; encoding the current frame block, and adding flag information indicating the addition of a mean pixel value applied to the encoded current frame block and identification information on the encoding mode as header information corresponding to the encoded current frame block.

Abstract: There are provided selective prediction encoding and decoding methods and selective prediction encoding and decoding devices. The selective prediction encoding device selects and performs one of an AC/DC prediction encoding method and an intra prediction encoding method which corresponds to the smaller of code amount from AC/DC prediction and an amount of AVC intra coding, records information indicating the selected encoding method in a header of a bit stream, and transmits the bit stream to the selective prediction decoding device. The selective prediction decoding device decodes the transmitted bit stream by the use of a decoding process corresponding to the information recorded in the header. Accordingly, it is possible to improve compression ratio and image quality by using the selective prediction encoding and decoding methods.

Abstract: A method, medium, and apparatus predicting direct mode motion of a multi-angle moving picture on a temporal and spatial basis. The method may include locating a block to which a co-located block of a block for which coding is sought makes reference with a motion vector, calculating a forward motion vector and a backward motion vector by making reference to pictures of an adjacent camera that exists in a direction parallel to a direction corresponding to the motion vector when a reference picture is not taken by the same camera as the picture to which the block for which coding is sought belongs, and calculating forward and backward reference blocks of the block for which coding is sought by applying weights to the calculated motion vectors. Therefore, the moving picture can be coded/decoded by locating motion vectors of previous and subsequent pictures without predicting motion, reducing calculation and performance time.

Abstract: The present invention discloses an encoding apparatus using a Discrete Cosine Transform (DCT) scanning, which includes: a mode selection means for selecting an optimal mode for intra prediction; an intra prediction means for performing intra prediction onto video inputted based on the mode selected in the mode selection means; a DCT and quantization means for performing DCT and quantization onto residual coefficients of a block outputted from the intra prediction means; and an entropy encoding means for performing entropy encoding onto DCT coefficients acquired from the DCT and quantization by using a scanning mode decided based on pixel similarity of the residual coefficients.

Abstract: A data transmitter transmitting a data packet containing identifier information including a kind of data, a sequence of data, and/or a packet generating sequence. A receiver extracting a packet number and the identifier information for an error-receipt occurring data packet based upon the identifier information recorded in a header of the packet, generating retransmission control information, such as retransmission times and priority, based on the extracted packet number and the identifier information and transmitting the retransmission control information to the transmitter of the packet. The retransmitting the error-occurring data packet according to the received retransmission control information. The number of retransmissions and the retransmission priority can be varied according to characteristics of the transmitted data, so that retransmissions is suitable for the characteristics of the data and to more stably receive the data that is more influential to the restoration of the data.

Abstract: A signal adaptive filtering method for reducing blocking effect and ringing noise, a signal adaptive filter, and a computer readable medium. The signal adaptive filtering method capable of reducing blocking effect and ringing noise of image data when a frame is composed of blocks of a predetermined size includes the steps of: (a) generating blocking information for reducing the blocking effect and ringing information for reducing the ringing noise, from coefficients of predetermined pixels of the upper and left boundary regions of the data block when a frame obtained by deconstructing a bitstream image data for inverse quantization is an intraframe; and (b) adaptively filtering the image data passed through inverse quantization and inverse discrete cosine transform according to the generated blocking information and ringing information. Therefore, the blocking effect and ringing noise can be eliminated from the image restored from the block-based image, thereby enhancing the image restored from compression.

Abstract: A method of and apparatus for encoding and decoding a signal by illumination change compensated motion estimation are provided. The apparatus for encoding a signal by illumination change compensated motion estimation includes: an illumination change compensation unit performing compensation for an illumination change by performing a differential calculation between each pixel value of a current block and the means pixel value of a reference block indicated by a motion vector of the current block and the mean pixel value of the reference block; a residual signals generation unit generating residual signals based on the blocks in which illumination change compensation is performed; and an illumination changed amount prediction unit performing differential pulse code modulation (DPCM) based on the illumination change amount prediction value by reflecting the closeness between neighboring blocks in which illumination change occurs.

Abstract: Provided are a method of and apparatus for lossless video encoding and decoding, in which a differential residual block generated by calculating a difference between pixels of a residual block resulting from interprediction is encoded, thereby improving the compression rate. The method of lossless video encoding includes performing interprediction between a reference frame and a current frame in units of a predetermined-size block to generate a predicted block of a current block to be encoded, generating a residual block composed of residual signals corresponding to differences between pixels of the predicted block and the current block, calculating differences between the residual signals of the residual block in a predetermined direction and generating a differential residual block based on the calculated differences, and performing entropy-encoding on the differential residual block.

Abstract: Provided are an apparatus for multi-stage transforming a plurality of unit blocks in multi-dimension that can improve compression efficiency of video data by collecting Discrete Cosine Transforming (DCT) coefficients of neighboring blocks and performing an additional transformation based on the DCT coefficients of an original picture and a differential picture. The method includes the steps of: performing a Discrete Cosine Transform (DCT) on inputted picture data and selecting R blocks of a predetermined size from DCT picture data, where R is a natural number equal to or greater than 2; arranging DCT coefficients of each of the selected R blocks according to each frequency in one-dimension; and performing one-dimensional transformation again on the DCT coefficients arranged in one-dimension.

Abstract: Provided are a filtering method and apparatus for removing blocking artifacts and ringing noise. The filtering method includes transforming video data on a block-by-block basis, and detecting the presence of an edge region in the video data by checking the distribution of values obtained by the transformation. Accordingly, it is possible to completely remove blocking artifacts and/or ringing noise by more effectively detecting the presence of an edge region in video data.

Abstract: A transcoding method and apparatus and a motion vector interpolation method. The transcoding method and apparatus convert moving picture data from one encoding format to another encoding format. The transcoding method includes (a) decoding an image coded in a first encoding method and then obtaining encoding mode information and motion vector information of each block of the image; (b) selecting at least one of available encoding modes of a second encoding method based on the encoding mode information of each block of the decoded image; and (c) performing a motion estimation process on each block of the decoded image in the at least one selected encoding mode and then determining an optimal encoding mode for each block of the decoded image based on the motion estimation result(s).

Abstract: An apparatus and method of transceiving a bit stream, by which a video bit stream is stably transmitted by the effective use of two logic channels when communication is established by the two logic channels during transmission of the video bit stream in a communication network, is provided. In this method, a source is encoded into a bit stream using a predetermined type of coding. Then, the encoded bit stream is transmitted to each communication protocol layer, while the header of each communication protocol layer is added to a payload. The header is transmitted separately from the bit stream.

Abstract: Provided is an apparatus and method for encoding and decoding using alternative transform units according to the correlation of residual signals. The video encoding apparatus includes a first transforming unit for performing discrete cosine transform (DCT), first quantization, first inverse quantization, and inverse DCT on a block basis onto residual coefficients generated after intra frame prediction or inter frame prediction; a second transforming unit for performing discrete sine transform (DST), second quantization, second inverse quantization, and inverse DST on a block basis onto the residual coefficients; a selecting unit for selecting one having a high compression rate between the first and second transforming units for each block through performing rate-distortion optimization; and a flag marking unit for recording information about the selected transforming unit at a flag bit provided on a macroblock basis.

Abstract: Provided is a multiple camera system, and more particularly, a method and apparatus for processing hopping default views in an apparatus for encoding/decoding video streams of multiple view positions. The encoding apparatus for the multiple camera system includes an encoder for receiving video signals of multiple view positions, and encoding the video signals based on a predetermined default Group of Pictures (GoP); a default GoP selector for providing the default GoP information to the encoder; and a multiplexer for multiplexing the encoded video signals and sequentially outputting only the default GoP.

Abstract: Provided are a filtering method and apparatus for removing blocking artifacts and ringing noise. The filtering method includes transforming video data on a block-by-block basis, and detecting the presence of an edge region in the video data by checking the distribution of values obtained by the transformation. Accordingly, it is possible to completely remove blocking artifacts and/or ringing noise by more effectively detecting the presence of an edge region in video data.

Abstract: Provided is a video encoding and decoding method and apparatus using pixel-based prediction. A pixel-based video encoding apparatus includes a block prediction unit, a residual image generation unit, a pixel prediction unit, and an entropy-coding unit. The block prediction unit performs temporal or spatial prediction between a reference image and a current image in order to generate a prediction block corresponding to a current block to be encoded. The residual image generation unit generates a residual image block composed of a residual signal corresponding to a difference between pixels of the prediction block and pixels of the current block.

Abstract: A data transmitter transmitting a data packet containing identifier information including a kind of data, a sequence of data, and/or a packet generating sequence. A receiver extracting a packet number and the identifier information for an error-receipt occurring data packet based upon the identifier information recorded in a header of the packet, generating retransmission control information, such as retransmission times and priority, based on the extracted packet number and the identifier information and transmitting the retransmission control information to the transmitter of the packet. The retransmitting the error-occurring data packet according to the received retransmission control information. The number of retransmissions and the retransmission priority can be varied according to characteristics of the transmitted data, so that retransmissions is suitable for the characteristics of the data and to more stably receive the data that is more influential to the restoration of the data.