Abstract: A moving image decoding method is provided for generating a prediction image using an intra-frame prediction mode. The moving image decoding method includes deriving a first parameter and a second parameter by using a sampled luminance value down-sampled according to a chrominance format and the intra-frame prediction mode; and deriving the prediction image by using the first parameter and the second parameter, wherein: the first parameter is derived by: deriving a logarithmic value of a luminance difference value, deriving a first value by right-shifting a second value related to the luminance difference value by the logarithmic value, and using a third value acquired by multiplying a fourth value by a chrominance difference value, wherein the fourth value is determined from a reference table by using the first value, and the second parameter is derived by using the first parameter.

Abstract: A load in processing of searching for a motion vector is reduced. In order to solve the problem described above, a motion vector derivation apparatus according to one aspect of the present invention that derives a motion vector to be referred to for generating a prediction image to be used for coding or decoding of a video includes a motion vector search unit configured to search for a motion vector on a prediction unit basis through matching processing. The motion vector search unit is configured to stop search of the motion vector, depending on whether or not a conditional expression according to a pixel bit-depth is satisfied.

Abstract: A video decoding apparatus is a video decoding apparatus for deriving a prediction image by using a reference picture included in a reference picture list.

Abstract: Provided is a video decoding apparatus for decoding coded data of a tile group in which a picture is split into rectangular regions, the tile group being composed of segments, the video decoding apparatus including: a header decoder configured to decode the number of tiles, a WPP enabled flag, and a slice enabled flag indicating whether segments in a target tile group are rectangular tiles, CTU rows, or slices from a tile group header, wherein the header decoder is configured to decode only one of the number of tiles being two or more, the WPP enabled flag being 1, and the slice enabled flag being 1 in one tile group.

Abstract: To achieve a reduction in the amount of coding taken in the use of an asymmetric partition and to implement efficient encoding/decoding processes exploiting the characteristics of the asymmetric partition. In a case that a CU information decoding unit decodes information for specifying an asymmetric partition (AMP; Asymmetric Motion Partition) as a partition type, an arithmetic decoding unit is configured to decode binary values by switching between arithmetic decoding that uses contexts and arithmetic decoding that does not use contexts in accordance with the position of the binary values.

Abstract: A video decoding apparatus including a parameter decoding circuit, a prediction parameter derivation circuit, a motion compensation circuit, and a weighted prediction circuit is provided. The parameter decoding circuit is configured to decode a flag and a syntax element. The prediction parameter derivation circuit is configured to derive inter prediction parameters. The motion compensation circuit is configured to generate interpolation images based on the inter prediction parameters and reference pictures. The weighted prediction circuit is configured to derive the weight coefficients using the syntax element, and generate a prediction image using the interpolation images and the weight coefficients. When the flag indicates that the weighted prediction information is present in the slice header, the weighted prediction circuit sets a variable NumWeightL1 indicating a number of weights for a reference picture list 1 to be equal to a value of a variable NumRefIdxActive[1] derived from the slice header.

Abstract: Object There is the problem in the related art that the relationship between a patch size which is a unit of processing of a neural network and the sizes of input and output pictures is not clearly defined.

Abstract: A moving image decoding method for deriving a prediction image of a chrominance image by using a luminance image is provided. The method derives a first luminance value and a first chrominance value corresponding to a first position, and derives a second luminance value and a second chrominance value corresponding to a second position. The method further derives a first difference value between the first and second luminance values, and derives a second difference value between the first and second chrominance values. The method sets a shift value to a first threshold based on a comparison between the first threshold and a third value, being calculated by adding a first specified value to a first value, derived by using the first difference value, and then subtracting a second value, derived by using the second difference value, from an addition result, and derives the prediction image by using the shift value.

Abstract: An image decoding apparatus includes: a first filter unit configured to apply a first filter to an image (a luminance image and a chrominance image); a second filter unit configured to apply a second filter to an output image of the first filter; a filter set derivation unit configured to decode a filter coefficient from coded data; and a third filter unit configured to apply a third filter to an output image of the second filter by using the filter coefficient. In a case that the third filter unit performs filter processing for the luminance image by using a luminance output image of the second filter, the third filter unit performs processing of clipping an amount of change of a pixel value through the filter processing within a prescribed range of value.

Abstract: According to an aspect of the present disclosure, an image decoding apparatus for decoding information specifying a neural network includes: header decoding circuitry that decodes an input tensor identification parameter specifying a process for deriving an input tensor input for a post filter of the neural network. The input tensor identification parameter is a parameter related to a color component channel.

Abstract: A video decoding apparatus includes a matrix reference pixel derivation unit that derives, as a reference image, an image obtained by downsampling an image adjacent to a top side and a left side of a target block, a mode derivation unit that derives a candidate list of prediction modes used for a target block according to the reference image and a size of the target block, a prediction processing parameter derivation unit that derives a prediction processing parameter used to derive a prediction image according to the candidate list, a matrix intra prediction mode indicator, and the size of the target block, a matrix prediction image derivation unit that derives a prediction image based on an element of the reference image and the prediction processing parameter, and a matrix prediction image interpolation unit that derives the prediction image or an image obtained by interpolating the prediction image, as a prediction image.

Abstract: Delay based on WPP processing is reduced. An image decoding apparatus (31) includes: a prediction image generation unit (308) by using decoded data from a first position to a second position, the first position being, in a CTU row immediately above a CTU row including a target CTU, identical to a position of the target CTU, the second position being a position one CTU forward relative to the first position; and an entropy decoding unit (301) that performs decoding of the target CTU by using the decoded data from the first position to the second position, the first position being, in the CTU row immediately above the CTU row including the target CTU, identical to the position of the target CTU, the second position being a position one CTU forward relative to the first position.

Abstract: In a case that a scaling value of neural network filter strength is set equal to 0, a decoded image before a deblocking filter is output, and thus block noise occurs. In a case that luma and chroma parameters are not taken into consideration, processing for an image of multiple transfer functions and chroma parameters is not appropriately performed. In a unit of a prescribed block, by using a parameter indicating a degree of application of the NN filter, an image after the deblocking filter and an image after an NN filter are combined using a different ratio of the images. Filter processing of a luma image is switched based on a luma parameter, and filter processing of a chroma image is switched based on a chroma parameter.

Abstract: Memory required during decoding is reduced. A video image decoding device (1) is equipped with main direction deriving means (1453A) that references a prediction mode definition DEFPM(1), and from a prediction mode number, derives a main direction of a prediction direction corresponding to a prediction mode, and a gradient deriver (1453B) that references a gradient definition table DEFANG(1), and derives a gradient of the prediction direction.

Abstract: A video decoding apparatus includes matrix reference pixel derivation circuitry that derives reference samples by using top neighboring samples and left neighboring samples of a current block, weight matrix derivation circuitry that derives a weight matrix, matrix prediction image derivation circuitry that derives a prediction image, and matrix prediction image interpolation circuitry that derives a predicted image by using the prediction image. A size index is derived according to a value of a target block width and a value of a target block height. A prediction size is derived using the size index. In a case that a first condition, that both the value of the transform block width and the value of the transform block height are equal to 4, is true, the size index is set equal to 0 and the prediction size is set equal to 4.

Abstract: A video decoding apparatus is a video decoding apparatus for deriving a prediction image by using a reference picture included in a reference picture list.

Abstract: An image decoding apparatus and an image coding apparatus that reduce complexity of high image quality processing are implemented. The image decoding apparatus includes an inter prediction parameter decoding processing unit that includes processing of, regarding two motion vectors, modifying the two motion vectors from an error of two prediction images. In a case that neither of the two prediction images is a case of weighted prediction, the processing of modifying the two motion vectors is performed.

Abstract: In a case that two reference picture lists are selected with one index value, the reference picture lists may not be determinable depending on the number of two reference picture list structures. Provided is a prediction unit that decodes a reference picture list structure including multiple reference picture lists and selects two reference picture lists from the reference picture list structure for each picture or for each slice. The prediction unit selects two reference picture lists with one index value depending on the number of two reference picture list structures.

Abstract: A prediction image generation is provided. First and second luminance values corresponding, respectively, to first and second positions on a luminance image are derived. First and second chrominance values corresponding, respectively, to first and second positions on a chrominance image are derived. First and second difference values indicate, respectively, a first difference between the first and second luminance values and a second difference between the first and second chrominance values. A shift value is derived for a shift operation and a first parameter is derived by using the first and second difference values, and a second parameter is derived by using the second luminance value, the second chrominance value, the first parameter, and the shift value according to a formula. The shift value is set to a first threshold if a value derived by using the first and second difference values is less than the first threshold.

Abstract: A coding device and a decoding device are configured to include an estimated prediction mode deciding section (122a) including: a reference block selecting section (1223a) for selecting a reference block for use in estimating an intra-prediction mode for a subject block; an estimating number deciding section (1222a) for deciding an estimating number of estimated values to be estimated for the intra-prediction mode; and an estimated prediction mode deriving section (1221a) for estimating, based on a reference block, the estimating number of estimated values of the prediction mode.