Abstract: When an encoding mode corresponding to one of blocks to be encoded into which an image is divided by a block dividing part 2 is an inter encoding mode which is a direct mode, a motion-compensated prediction part 5 selects a motion vector suitable for generation of a prediction image from one or more selectable motion vectors and also carries out a motion-compensated prediction process on the block to be encoded to generate a prediction image by using the motion vector, and outputs index information showing the motion vector to a variable length encoding part 13, and the variable length encoding unit 13 variable-length-encodes the index information.

Abstract: When an encoding mode corresponding to one of blocks to be encoded into which an image is divided by a block dividing part 2 is an inter encoding mode which is a direct mode, a motion-compensated prediction part 5 selects a motion vector suitable for generation of a prediction image from one or more selectable motion vectors and also carries out a motion-compensated prediction process on the block to be encoded to generate a prediction image by using the motion vector, and outputs index information showing the motion vector to a variable length encoding part 13, and the variable length encoding unit 13 variable-length-encodes the index information.

Abstract: When an intra prediction parameter indicates a horizontal prediction process, an intra prediction unit adds a value proportional to a change in a horizontal direction of the luminance values of pixels adjacent to the top of each block, which is a unit for prediction process of a coding block, to the luminance value of a pixel adjacent to the left of the block to set a result of the addition as a predicted value of a prediction image, whereas when the intra prediction parameter indicates a vertical prediction process, the intra prediction unit adds a value proportional to a change in a vertical direction of the luminance values of pixels adjacent to the left of the block to the luminance value of the pixel adjacent to the top of the block to set the result of the addition as a predicted value of the prediction image.

Abstract: When removing a block distortion occurring in a local decoded image, a loop filtering part 11 of an image coding device carries out a filtering process on each of signal components (a luminance signal component and color difference signal components) after setting the intensity of a filter for removing the block distortion for each of the signal components according to a coding mode (an intra coding mode or an inter coding mode) selected by a coding controlling part 1.

Abstract: When carrying out an average prediction, an intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor also sets a filter coefficient to ½, associated with the intermediate prediction value for a target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with an adjacent pixel adjacent to an upper side or a left side of the target pixel. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.

Abstract: When an intra prediction parameter indicates a horizontal prediction process, an intra prediction unit adds a value proportional to a change in a horizontal direction of the luminance values of pixels adjacent to the top of each block, which is a unit for prediction process of a coding block, to the luminance value of a pixel adjacent to the left of the block to set a result of the addition as a predicted value of a prediction image, whereas when the intra prediction parameter indicates a vertical prediction process, the intra prediction unit adds a value proportional to a change in a vertical direction of the luminance values of pixels adjacent to the left of the block to the luminance value of the pixel adjacent to the top of the block to set the result of the addition as a predicted value of the prediction image.

Abstract: An encoding controlling unit 3 selects one transformation block size which provides an optimal degree of encoding efficiency from a set of transformation block sizes which are determined in accordance with an encoding mode 7, and includes the transformation block size selected thereby in optimal compression parameters 20a to notify the transformation block size to a transformation/quantization unit 19, and the transformation/quantization unit 19 divides an optimal prediction differential signal 13a into blocks having the transformation block size included in the optimal compression parameters 20a, and carries out a transformation and quantization process on each of the blocks to generate compressed data 21.

Abstract: When removing a block distortion occurring in a local decoded image, a loop filtering part 11 of an image coding device carries out a filtering process on each of signal components (a luminance signal component and color difference signal components) after setting the intensity of a filter for removing the block distortion for each of the signal components according to a coding mode (an intra coding mode or an inter coding mode) selected by a coding controlling part 1.

Abstract: When carrying out an average prediction, an intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor also sets a filter coefficient to ¾, associated with the intermediate prediction value for a target pixel at the upper end of the block other than the target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with the adjacent pixel adjacent to the upper side of the target pixel at the upper end of the block. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.

Abstract: When carrying out an average prediction, the intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor sets a filter coefficient to ½, associated with the intermediate prediction value for a target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with an adjacent pixel adjacent to an upper side or a left side of the target pixel. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.

Abstract: An intra-scene and inter-scene adaptive coding unit 6 converts an MPEG-2 video bit stream into a slave stream by using both coded data which is included in the coded data about scene video units in a master stream recorded in a data recording unit 2 and for which alternative coded data to be used for prediction reference has not been retrieved by an inter-scene prediction determining unit 5, and coded data retrieved by the inter-scene prediction determining unit 5 for the prediction reference.

Abstract: Disclosed is an image decoding method including a step of variable-length-decoding coded data multiplexed into a bitstream to acquire compressed data associated with a coding block, a reference image restriction flag indicating whether or not to restrict a significant reference image area which is an area on a reference image which can be used for the motion-compensated prediction, and motion information and a motion-compensated prediction step of carrying out a motion-compensated prediction process on the coding block on the basis of the motion information to generate a prediction image, in which the motion-compensated prediction step includes a step of when the prediction image includes a pixel located outside the significant reference image area, carrying out a predetermined extending process to generate the prediction image on the basis of the reference image restriction flag by using the motion information.

Abstract: When carrying out an average prediction, an intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor also sets a filter coefficient to ¾, associated with the intermediate prediction value for a target pixel at the left end of the block other than the target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with the adjacent pixel adjacent to the left side of the target pixel at the left end of the block. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.

Abstract: When generating a prediction image of a color difference signal, an intra prediction unit 4 carries out an intra prediction process on a target block to be encoded of a color difference signal by using the same intra prediction parameter as that which the intra prediction unit 4 uses when carrying out an intra prediction process on a target block to be encoded of a luminance signal, or carries out the intra prediction process on the target block to be encoded of the color difference signal by applying an average prediction to the target block to be encoded. A variable length encoding unit 13 variable-length-encodes a flag showing whether the intra prediction unit 4 uses the same intra prediction parameter as that used for the luminance signal.

Abstract: When carrying out an average prediction, an intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor also sets a filter coefficient to ¾, associated with the intermediate prediction value for a target pixel at the left end of the block other than the target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with the adjacent pixel adjacent to the left side of the target pixel at the left end of the block. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.

Abstract: When an encoding mode corresponding to one of blocks to be encoded into which an image is divided by a block dividing part 2 is an inter encoding mode which is a direct mode, a motion-compensated prediction part 5 selects a motion vector suitable for generation of a prediction image from one or more selectable motion vectors and also carries out a motion-compensated prediction process on the block to be encoded to generate a prediction image by using the motion vector, and outputs index information showing the motion vector to a variable length encoding part 13, and the variable length encoding unit 13 variable-length-encodes the index information.

Abstract: When carrying out an average prediction, an intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor also sets a filter coefficient to ¾, associated with the intermediate prediction value for a target pixel at the upper end of the block other than the target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with the adjacent pixel adjacent to the upper side of the target pixel at the upper end of the block. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.

Abstract: When carrying out an average prediction, the intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor sets a filter coefficient to ½, associated with the intermediate prediction value for a target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with an adjacent pixel adjacent to an upper side or a left side of the target pixel. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.

Abstract: When carrying out an average prediction, an intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor also sets a filter coefficient to ½, associated with the intermediate prediction value for a target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with an adjacent pixel adjacent to an upper side or a left side of the target pixel. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.

Abstract: When carrying out an average prediction, an intra predictor carries out a filtering process on target pixels of the intra prediction located at an upper end and a left end of the block, the filtering process using an intermediate prediction value, which is an average value of adjacent pixels of the block, and at least one adjacent pixel of the target pixel. The intra predictor also sets a filter coefficient to ¾, associated with the intermediate prediction value for a target pixel at the left end of the block other than the target pixel at an upper left corner of the block, and sets a filter coefficient to ¼, associated with the adjacent pixel adjacent to the left side of the target pixel at the left end of the block. As a result, prediction errors locally occurring can be reduced, and the image quality can be improved.