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 (3032, 3036 to 3038) 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 (30373) configured to search for a motion vector on a prediction unit basis through matching processing. The motion vector search unit (30373) 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 mechanism is provided that implements video coding and decoding such that only a specific partial image region on a screen can be independently decoded. A video decoding apparatus (31) according to an aspect of the present invention configures, in intra prediction, inter prediction, loop filter processing, or the like, a partial image region in a picture, handles a region outside the partial image region in a similar manner to a region outside the picture, and does not apply such restriction to a non-partial image region other than the partial image region in the picture.

Abstract: An image decoding apparatus is implemented that can suppress a decrease in coding efficiency in a case that a high compression rate is achieved. The image decoding apparatus includes a parameter decoder, and the parameter decoder decodes a skip flag indicating whether a skip mode is applied, and in a case that the skip flag does not indicate the skip mode, decodes a merge flag indicating whether a merge mode is applied, and in a case that the merge flag does not indicate the merge mode, decodes an MMVD flag indicating whether an MMVD mode is applied.

Abstract: According to an embodiment, an encoding device includes a deriving unit and an encoding unit. The deriving unit is configured to derive a first reference value based on fixed point precision representing roughness of a weighting factor that is used for multiplying a reference image. The encoding unit is configured to encode a first difference value that is a difference value between the weighting factor and the first reference value and the fixed point precision. The weighting factor is included in a first range of predetermined bit precision having the first reference value at approximate center. The first difference value is in the predetermined range.

Abstract: A method of dividing an input image signal into pixel blocks, and performing inter-prediction on the divided pixel blocks. This method includes selecting predicted motion information from a motion information buffer storing motion information in an encoded region, and predicting motion information of an encoding target block by using the predicted motion information. The method further includes acquiring representative motion information from a plurality of items of motion information in an encoded region in accordance with first information indicating a method of selecting the predicted motion information, thereby obtaining only the representative motion information.

Abstract: An encoding apparatus according to an embodiment includes a specifying unit, a first encoder and a second encoder. The specifying unit specifies a first original image signal included in an original image signal. The first encoder generates base image encoded data obtained by encoding the first original image signal by inter-frame prediction using a reference image signal. The second encoder generates standard encoded data obtained by encoding a second original image signal serving as the original image signal other than the first original image signal by the inter-frame prediction based on the base image encoded data.

Abstract: In a case of referring to information between pictures by means of inter prediction, the entire picture needs to be decoded even in a case of decoding a small region. In a case of referring to information within a picture by means of intra prediction, referring to information across a tile boundary is not possible. In a case that a pixel pointed by a sub-block level motion vector of a target block that is calculated by scaling based on an available motion vector acquired from a spatial neighboring block or a temporal neighboring block is not present within a tile sequence, a process of replacing the pixel value with a pixel value within the tile sequence is performed. In a case of referring to a pixel outside of a tile by means of intra prediction, a process of replacing the pixel value with that of a pixel within the tile is performed.

Abstract: An encoding device includes: an index setting unit that sets an index that represents information of a reference image and a weighting factor; an index reconfiguring unit that predicts a reference value of the weighting factor, wherein the reference value indicates a factor to be set if a difference of pixel value between a reference image and a target image to be encoded is less than or equal to a specific value; and an entropy encoding unit that encodes a difference value between the weighting factor and the reference value.

Abstract: An encoding device includes an index setting unit that sets an index that represents information of a reference image and a weighting factor. An index reconfiguring unit predicts a reference value of the weighting factor. The reference value indicates a factor to be set if a difference of pixel value between a reference image and a target image to be encoded is less than or equal to a specific value. An entropy encoding unit encodes a difference value between the weighting factor and the reference value.

Abstract: An apparatus includes an inter prediction unit configured to decode multiple reference picture list structures and to select one reference picture list structure from the multiple reference picture list structures on a per picture basis or on a per slice basis, wherein in the multiple reference picture list structures, the number of all reference pictures is one or more.

Abstract: A prediction image generation method is provided. The method derives a down-sampled luminance image and a down-sampled neighboring luminance image by down-sampling the luminance image of a target block and a neighboring luminance image based on information related to a down-sampling and indicating one of a plurality of position relationships between at least one luma pixel and a chroma pixel. The method derives a neighboring chrominance image, parameters derived from the down-sampled neighboring luminance image and the neighboring chrominance image, and the prediction image by using the down-sampled luminance image and the parameters. The position relationships include that a position of the chroma pixel is identical to a position of one of the at least one luma pixel and that the position of the chroma pixel is located in an intermediate of two of the at least one luma pixel on a left side of a 2×2 luma pixel block.

Abstract: In a scheme in which only a part of one picture is intra-predicted and the rest of the region is inter-predicted, generation of a significant code amount and generation of a delay can be avoided in a specific picture. However, because only a part of the picture is coded by means of the intra prediction, coding efficiency is deteriorated as compared to an I picture in which the entire picture is coded by means of the intra prediction. A picture is split into a restricted region and a non-restricted region. Prediction is performed by using an intra prediction in which only a pixel of the restricted region is referred to or an inter prediction in which a restricted reference region of a reference picture is referred to for a block of the restricted region. Prediction is performed by using the intra prediction in which a decoded pixel in the picture is referred to or the inter prediction in which the reference picture is referred to for the block of the non-restricted region.

Abstract: According to one embodiment, an image encoding method includes selecting a motion reference block from an already-encoded pixel block. The method includes selecting an available block including different motion information from the motion reference block, and selecting a selection block from the available block. The method includes generating a predicted image of the encoding target block using motion information of the selection block. The method includes encoding a prediction error between the predicted image and an original image. The method includes encoding selection information identifying the selection block by referring to a code table decided according to a number of the available block.

Abstract: The coding efficiency and the amount of processing can be further improved in methods that use the correlation between spatial and temporal directions to estimate parameters that are required for predictions. In LM prediction that predicts pixel values of chrominance, based on pixel values of luminance, an index for a filter that downsamples a luminance image is adaptively signalled.

Abstract: To suppress an overhead of a flag indicating a motion compensation filter. A motion compensation filter apparatus includes a motion compensation filter unit configured to switch a filter to apply on a full sample image in a certain unit, and an MC filter parameter derivation unit configured to select a switching unit for filter switching by the motion compensation filter unit.

Abstract: An adaptive motion vector prediction unit configured to adaptively perform spatial prediction that performs prediction using a motion vector around a target block and temporal prediction that performs prediction using a motion vector of a collocated picture is included, and in the temporal prediction performed by the adaptive motion vector prediction unit, the collocated picture to be referred to is designated on a per picture basis, and a reference list is designated on a per slice basis.

Abstract: According to an embodiment, a decoding device includes an acquiring unit configured to acquire first format information, encoded data, and first filter information, the first format information indicating a resolution of a color-difference component of the encoded data; a decoding unit configured to decode the encoded data to obtain a decoded image; and a converting unit configured to convert a color-difference formal of the decoded image represented by a first color-difference format by using a filter identified by the filter information.

Abstract: An encoding device includes an index setting unit that sets an index that represents information of a reference image and a weighting factor, and an index reconfiguring unit that predicts a reference value of the weighting factor. The reference value indicates a factor to be set if a difference of pixel value between a reference image and a target image to be encoded is less than or equal to a specific value. The encoding device also includes an entropy encoding unit that encodes a difference value between the weighting factor and the reference value.

Abstract: A video encoding apparatus is a video encoding apparatus for subjecting a video image to motion compensated prediction coding, comprising an acquisition module to acquire available blocks of blocks having motion vectors from encoded blocks adjacent to a to-be-encoded block and number of the available blocks, an acquisition/selection module to select one selection block from the encoded available blocks, a selection information encoder to encode selection information specifying the selection block using a code table corresponding to the number of available blocks, and an image encoder to subject the to-be-encoded block to motion compensated prediction coding using a motion vector of the selection block.

Abstract: A slice or a tile can be decoded in a single picture, without reference to information outside of a target slice or outside of a target tile. However, there are problems in that in order to decode some regions of a video in a sequence, the entire video needs to be reconstructed, and in that the slice and the tile coexist in the single picture, and the slices include an independent slice and dependent slice, causing the coding structure to be complex. In the present invention, a flag indicating whether a shape of a slice is rectangular or not is decoded, and in a case that the flag indicates that the shape of the slice is rectangular, a position and a size of the slice that is rectangular are not changed in a period of time of referring to a same SPS. The slice that is rectangular is decoded independently without reference to information of another slice. As described above, introducing the slice that is rectangular instead of the tile can simplify the coding structure that is complex.