Abstract: Provided are a filtering method and apparatus for removing blocking artifacts and/or ringing noise. The filtering apparatus includes (a) performing one-dimensional discrete cosine transform (1D DCT) on video data on a block-by-block basis in a horizontal or vertical direction; (b) performing 1D DCT in the other direction of (a) and quantization on at least one of 1D DCT coefficients for a pixel obtained by performing 1D-DCT on the video data, the pixel being selected according to pixel position; and (c) generating filtering information based on the quantized pixel coefficient obtained from (b). According to the filtering method and apparatus, it is possible to reduce the amount of calculation when obtaining filtering information to remove the blocking artifacts and/or ringing noise.

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: Provided are a motion estimation device and method adaptive to change in illumination.

Abstract: Provided are method and device for down-sampling an image from H.264 to MPEG-4 at a high speed. The image down-sampling transcoding 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: 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: 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 wireless packetization apparatus for transmitting and/or receiving multimedia data including video data in a radio transmitting/receiving system, and a method thereof are provided. According to the present invention, error resilience can be increased by adding error protection codes to one portion and a plurality of portions of multimedia-related header information, respectively, when multimedia data such as video data requiring real time or low delay are transmitted and received in a wireless environment, and a packet drop rate can thereby be reduced. Also, information can be more precise recovered by inserting length identifier and length information on an information region into the header.

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: A wireless packetization apparatus for transmitting/receiving multimedia data including video data in a radio transmitting/receiving system, and a method thereof are provided. According to the present invention, error resilience can be increased by adding an error detection code and a corruption indication flag to header information on a radio link protocol (RLP) layer when multimedia data such as video data requiring real time or low delay is transmitted and received in a wireless environment, and a packet drop rate can be thereby reduced.

Abstract: A variable length coding method and apparatus is provided. The variable length coding method includes the steps of (a) selecting predetermined macroblocks from among the previous macroblocks of a macroblock to be coded in a current frame, (b) analyzing the occurrence statistics of symbols with respect to the selected macroblocks, (c) resetting a mapping relationship based on the analyzed occurrence statistics of symbols, and (d) variable length coding a current macroblock based on the reset mapping relationship. The variable length coding method dynamically varies the mapping relationship between symbols and bit patterns based on the occurrence statistics of the symbols, thereby reducing the amount of bits generated when coding images of the same picture quality.

Abstract: Motion estimation of a macro block in inter16×16, inter16×8, and inter8×16 modes is performed and a determination of whether to further perform motion estimation in a P8×8 mode is made. Motion estimation in P8×8 mode is either omitted or performed and one mode is determined according to a rate distortion cost of the respective modes. Spatial prediction encoding may then be performed or omitted based on comparing the rate distortion cost of the one mode with a predetermined value. Accordingly, by selectively omitting variable block motion estimation and spatial prediction encoding which are the most complicated operations in an H.264 encoder, determining an encoding mode is rapidly performed such that encoding speed increases.

Abstract: A transcoding method, medium, and apparatus for transforming a coded video format into another coded video format. The transcoding method includes decoding a bitstream encoded using a first coding method to output data in a pixel domain and motion vector and macroblock information for each of macroblock of the bitstream, and performing motion compensation using the motion vector and macroblock information to encode the data in the pixel domain using a second coding method.

Abstract: An encoding method for wireless transceiving of multimedia data including video data, and an encoding device therefor are provided. The encoding method includes (a) generating a length field representing the number of bits of a payload, (b) generating an error correction code by performing error correction coding with respect to the length field, and (c) inserting the length field and the error correction code during radio link protocol (RLP) framing. The encoding method reduces overhead when multimedia data including video data is transmitted and received under the radio environment, and increases error robustness, thereby improving the quality of an image.

Abstract: A motion vector (MV) search method including: searching for an integer-pixel MV among integer pixels and choosing an integer pixel corresponding to the integer-pixel MV; searching for a half-pixel MV among half pixels around the chosen integer pixel and choosing a half pixel corresponding to the half-pixel MV; and searching, when the half pixel is chosen, for a quarter-pixel MV among only specified quarter pixels disposed between the chosen integer pixel and the chosen half pixel and around the chosen half pixel and choosing a quarter pixel corresponding to the quarter-pixel MV.

Abstract: A terminal that supports signaling used in the transmission and reception of the Moving Picture Experts Group (MPEG)-4 data. The terminal includes a video codec for performing video coding/decoding, an audio codec for performing audio coding/decoding, a multiplexer for performing multiplexing on encoded data, and a system controller for performing signaling for negotiating the terminal capability.

Abstract: A wireless communication system for video packet transmission is provided. The wireless transmission system includes a video encoder for encoding a video signal on a block-by-block basis, and a degree of importance determiner for determining the degree of importance of video data encoded in each block from predetermined parameters. The wireless transmission system also includes a data transmission determiner for determining the transmission priority, or whether to transmit the encoded video data, on the basis of at least the amount of encoded video data to be transmitted per unit time the wireless channel conditions, and the degree of importance of the encoded video data. Furthermore, the wireless transmission system includes a video data packetizing unit for packetizing the video data determined to be transmitted, and a wireless transmitter for wirelessly transmitting packetized 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.

Abstract: Provided are a filtering method and apparatus for removing blocking artifacts and/or ringing noise. The filtering apparatus includes (a) performing one-dimensional discrete cosine transform (1D DCT) on video data on a block-by-block basis in a horizontal or vertical direction; (b) performing 1D DCT in the other direction of (a) and quantization on at least one of 1D DCT coefficients for a pixel obtained by performing 1D-DCT on the video data, the pixel being selected according to pixel position; and (c) generating filtering information based on the quantized pixel coefficient obtained from (b). According to the filtering method and apparatus, it is possible to reduce the amount of calculation when obtaining filtering information to remove the blocking artifacts and/or ringing noise.

Abstract: A variable length coding method and apparatus is provided. The variable length coding method includes the steps of analyzing the occurrence statistics of symbols with respect to previous frames, generating a mapping table for variably mapping input symbols to bit patterns based on the analyzed occurrence statistics of the input symbols, resetting the mapping relationship between symbols and bit patterns based on the generated mapping table, and variable length coding a current frame based on the reset mapping relationship. The variable length coding method efficiently reduces the number of bits generated by dynamically varying the mapping between input symbols and bit patterns depending on the occurrence statistics of the input symbols.

Abstract: A loop-filtering method for reducing quantization effect generated when an image data is encoded and decoded, and an apparatus therefor. The loop-filtering method includes the steps of extracting a flag indicating whether the image data requires loop-filtering using the distribution of inverse quantized coefficients (IQCs) of an inverse quantized image data and a motion vector indicating the difference between the previous frame and the current frame. The image data corresponding to the flag is then filtered by a predetermined method if the extracted flag indicates a need for the loop-filtering. Using the flags and an adaptive filter reduces the quantization effect and is useful to reduce the amount of computation required for the filtering. Also, the filtering can be performed through parallel processing without multiplication and division, so that the complexity of hardware can be reduced.