Abstract: Provided is a video encoding method including: calculating a difference value between a rate-distortion (R-D) cost of a first coefficient level from among coefficient levels of a sub-block and an R-D cost of a second coefficient level adjacent to the first coefficient level by using a distortion difference calculated by using an integer of the first coefficient level and an integer of the second coefficient level and a rate variation between the first coefficient level and the second coefficient level; selecting one of the integer values of the first and second coefficient levels as a modified value of the first coefficient level based on the difference value; and outputting the modified value of the first coefficient level.

Abstract: Provided is a method of encoding an image, the method including determining a scanning sequence for transforming one or more sub-blocks included in a transformation block to be identical to a sequence of quantizing the one or more sub-blocks; determining a sub-block for transformation from among the one or more sub-blocks according to the determined scanning sequence; and performing transformation by applying one or more transformation matrixes with respect to the sub-block for transformation.

Abstract: Disclosed is a video data decoding method comprising receiving a bitsream comprising encoded image information; decoding an image based on the encoded image information and obtaining luma data allocated to luma channels comprising a plurality of channels and chroma data allocated to a chroma channel comprising one channel from data generated by decoding the image; merging the obtained luma data as luma data having one component; splitting the obtained chroma data into chroma data having a plurality of components; and reconstructing the image based on the luma data having one component generated by merging the obtained luma data and the split chroma data having the plurality of components.

Abstract: Provided are a method and apparatus for determining a merge mode by using motion information of a previous prediction unit. The method of determining a merge mode includes obtaining a merge mode cost of a lower depth based on a merge mode cost of a coding unit of an upper depth obtained by using motion information of a merge mode of the coding unit of the upper depth corresponding to a merge mode of the coding unit of the lower depth.

Abstract: A video encoding method includes: receiving an image; up-sampling the received image; and changing a sample value of an up-sampling region included in the up-sampled image and encoding the up-sampled image by using the changed sample value, wherein the up-sampling region is a region inserted into the received image by the up-sampling.

Abstract: Provided are a method and an apparatus for determining an intra prediction mode. The method includes: splitting a maximum coding unit into coding units of a first size; acquiring an edge direction of each of the coding units of the first size; grouping adjacent coding units of the first size based on uniformity of edge directions of the adjacent coding units of the first size; determining a size range of coding units to be applied to intra prediction on the intra prediction coding unit group; performing the intra prediction on the intra prediction coding unit group by using coding units having sizes included in the determined size range; and determining a coding unit for the intra prediction and an intra prediction mode of the coding unit by comparing costs according to the performed intra prediction on the coding units having the sizes included in the size range.

Abstract: Provided are a method and apparatus for encoding a video and a method and apparatus for decoding a video. The method of encoding includes: determining, for a current block, bidirectional motion estimation information comprising an L0 motion vector, an L1 motion vector, an L0 reference vector, and an L1 reference picture by performing bidirectional motion estimation on the current block; determining whether to use the determined bidirectional motion estimation information as prediction information of the current block based on whether the L0 reference picture and the L1 reference picture are the same and based on a difference value between the L0 motion vector and the L1 motion vector; and in response to determining to use the determined bidirectional motion estimation information as the prediction information of the current block, encoding the determined bidirectional motion estimation information as the prediction information of the current block.

Abstract: Provided are a method and a device for encoding a video to improve an intra prediction processing speed, and a method and a device for decoding the video. The method for encoding a video performs parallel intra prediction and includes: obtaining, by using pixels of peripheral blocks processed prior to a plurality of adjacent blocks, reference pixels used for intra prediction of each of the plurality of adjacent blocks; performing, by using the obtained reference pixels, intra prediction in parallel for each of the plurality of adjacent blocks; and adding reference pixel syntax information to a bitstream.

Abstract: The method for encoding data includes: receiving data; determining one quantizer from among a plurality of quantizers having a same quantization step size and different offset values; and transmitting an indicator and a quantized coefficient related to the determined quantizer. The method for decoding data includes: receiving an indicator and a quantized coefficient related to a quantizer; determining one de-quantizer from among a plurality of de-quantizers by using the indicator; and acquiring reconstructed data by de-quantizing the quantized coefficient by using the determined de-quantizer.

Abstract: Provided is a method for encoding and decoding a motion picture frame, which achieve natural picture conversion of frames near an Instantaneous Decoding Refresh-I (IDR-I) frame. The decoding method includes: decoding a first frame which is a P frame that is to be displayed last among a plurality of P frames that are to be displayed before an IDR-I frame is displayed; decoding the IDR-I frame; decoding a second frame which is a P frame that is to be displayed first among a plurality of P frames that are to be displayed after the IDR-I frame is displayed; and maintaining a reference frame stored in a buffer, for decoding the first frame until the second frame is decoded. Therefore, by allowing frames near an IDR-I frame to access reference frames stored in a buffer, natural picture conversion is possible, and accordingly smooth picture conversion without flickering is possible.

Abstract: A motion vector predicting method and apparatus for predicting motion vectors in image coding and decoding, including predicting a motion vector of each small block in a macro block divided into at least one small block. The method may include selecting at least one small block, where a motion vector can be estimated, using motion vector information of adjacent small blocks, and includes simultaneously performing a motion vector prediction of the selected small block. By reducing a 16-operation process, conventionally required for processing a macro block with 4×4 blocks, into an 11-operation process, the image coding and decoding processing times can be reduced without using a complicated motion vector predicting apparatus.

Abstract: Methods and apparatuses for encoding and decoding data. The method for encoding data includes: receiving data; determining one quantizer from among a plurality of quantizers having a same quantization step size and different offset values; and transmitting an indicator and a quantized coefficient related to the determined quantizer. The method for decoding data includes: receiving an indicator and a quantized coefficient related to a quantizer; determining one de-quantizer from among a plurality of de-quantizers by using the indicator; and acquiring reconstructed data by de-quantizing the quantized coefficient by using the determined de-quantizer.

Abstract: A method and apparatus for determining a prediction mode which is used during encoding of a current block is provided. In the method and apparatus, a prediction mode candidate group to be used for the current block is determined based on a prediction mode for a block positioned at the same location on a reference picture as a location of the current block encoded, predictive coding is performed on the current block by using predictive modes included in the prediction mode candidate group. Thus, image prediction efficient is improved, and the time and number of calculations required for prediction mode determination are reduced.

Abstract: A method and apparatus for generating user preference data regarding the color characteristic of an image is provided where a preference image comprises an image converted to have a color characteristic that a user prefers with respect to a predetermined reference image, a preference value comprises a color characteristic value of the preference image, and a reference value comprises a color characteristic value of the reference image. The method for generating user preference data comprises (a) obtaining an image color characteristic value of a preference image and a reference image, (b) generating {preference value, reference value} which corresponds to a pair of the preference value and the reference value, and (c) generating the pair {preference value, reference value} as preference meta-data having at least one feature block.

Abstract: An apparatus for providing image metadata includes an input unit, an image metadata decoding unit, and an image color temperature converting unit. The input unit receives an input image, metadata corresponding to the color temperature of the input image, and color temperature information preferred by a user. The image metadata decoding unit calculates a color temperature corresponding to the metadata. The image color temperature converting unit converts the color temperature of the input image using the color temperature calculated by the image metadata decoding unit and the color temperature information preferred by a user.

Abstract: A method and apparatus for generating user preference data regarding the color characteristic of an image and a method and apparatus for converting image color preference using the method and apparatus is provided. The method for generating user preference data comprises (a) obtaining an image color characteristic value of a preference image and a reference image, (b) generating {preference value, reference value} which corresponds to a pair of the preference value and the reference value, and (c) generating the pair {preference value, reference value} as preference meta-data having at least one feature block.

Abstract: Provided is a method for encoding and decoding a motion picture frame, which achieve natural picture conversion of frames near an Instantaneous Decoding Refresh-I (IDR-I) frame. The decoding method includes: decoding a first frame which is a P frame that is to be displayed last among a plurality of P frames that are to be displayed before an IDR-I frame is displayed; decoding the IDR-I frame; decoding a second frame which is a P frame that is to be displayed first among a plurality of P frames that are to be displayed after the IDR-I frame is displayed; and maintaining a reference frame stored in a buffer, for decoding the first frame until the second frame is decoded. Therefore, by allowing frames near an IDR-I frame to access reference frames stored in a buffer, natural picture conversion is possible, and accordingly smooth picture conversion without flickering is possible.

Abstract: A method of and apparatus for encoding and/or decoding an image are provided, in which motion estimation and compensation are performed by using a reference background image and a reference object image extracted from an input image frame. In the method and apparatus, a background image of each of input image frames is used, and a background area which any one image frame lacks is updated by using a background image of another image frame. In this way, a reference background image is generated and stored, and an object image in each image frame is stored as a reference object image. Then, by using the stored reference background images and reference object images, motion estimation and compensation are performed, thereby increasing encoding efficiency.

Abstract: A method and an apparatus for converting the color temperature of metadata and a method and an apparatus for providing image metadata are provided. The apparatus for providing image metadata includes an input unit, an image metadata decoding unit, and an image color temperature converting unit. The input unit receives an input image, metadata corresponding to the color temperature of the input image, and color temperature information preferred by a user. The image metadata decoding unit calculates a color temperature corresponding to the metadata. The image color temperature converting unit converts the color temperature of the input image using the color temperature calculated by the image metadata decoding unit and the color temperature information preferred by a user.

Abstract: A method and an apparatus for converting the color temperature of metadata and a method and an apparatus for providing image metadata are provided. The apparatus for providing image metadata includes an input unit, an image metadata decoding unit, and an image color temperature converting unit. The input unit receives an input image, metadata corresponding to the color temperature of the input image, and color temperature information preferred by a user. The image metadata decoding unit calculates a color temperature corresponding to the metadata. The image color temperature converting unit converts the color temperature of the input image using the color temperature calculated by the image metadata decoding unit and the color temperature information preferred by a user.