Abstract: An image decoding device includes: a motion compensation predictor configured to generate a prediction image signal of a prediction target block based on information about a motion vector in a unit of the block and a reference frame; an overlapped block motion compensator carrying out an overlapped block motion compensation process of correcting the prediction image signal of the prediction target block by subjecting the prediction image signal of the prediction target block and a prediction image signal generated based on information about a motion vector and a reference frame of an adjacent block of the prediction target block to weighted averaging; and a determinator determining whether the overlapped block motion compensation process is applied to the prediction target block or not. The determinator determines application of the overlapped block motion compensation process to the prediction target block, when unidirectional prediction is applied to the adjacent block.

Abstract: An image decoding device includes: a prediction signal generation unit that generates a prediction signal by intra prediction, wherein in a block to which intra sub-partitions are applied, the prediction signal generation unit refers to a pixel of a decoded block adjacent to the block when generating prediction signals of all sub-blocks in the block.

Abstract: An image decoding device (200) including a circuit that controls decoding of syntax for controlling a boundary width of a division mode of a sequence to be decoded.

Abstract: An image decoding device (200) includes a circuit that selects the motion vector candidates from among motion vectors of neighboring blocks of a block to be decoded based on the control information.

Abstract: In an image decoding device (200) according to the present invention, a blending unit (243) blends, in a case where all of a geometric partitioning mode, overlapped block motion compensation, and luma mapping with chroma scaling are valid for a current block, and the geometric partitioning mode includes inter prediction and intra prediction, luma-mapped luma components of the motion compensation sample, the overlapped block motion compensation sample, and the intra prediction sample to generate a prediction sample for a luma component of the current block.

Abstract: An image decoding device includes: a motion compensation predictor configured to generate a prediction image signal of a prediction target block based on information about a motion vector in a unit of the block and a reference frame; an overlapped block motion compensator carrying out an overlapped block motion compensation process of correcting the prediction image signal of the prediction target block by subjecting the prediction image signal of the prediction target block and a prediction image signal generated based on information about a motion vector and a reference frame of an adjacent block of the prediction target block to weighted averaging; and a determinater determining whether the overlapped block motion compensation process is applied to the prediction target block or not. The determinater determines application of the overlapped block motion compensation process to the prediction target block, when unidirectional prediction is applied to the adjacent block.

Abstract: An image decoding device according to the present invention includes a circuit, wherein the circuit: derives motion information for a geometric partitioning mode to generate a motion compensation sample; and derives an intra prediction mode for the geometric partitioning mode to generate an intra prediction sample, the circuit: derives a plurality of the intra prediction modes on the basis of adjacent reference samples or adjacent reference blocks adjacent to the block to be decoded, and selects, with use of a signaled index, one or a plurality of intra prediction modes from an intra prediction mode candidate list including the plurality of derived intra prediction modes to generate the intra prediction sample.

Abstract: In an image decoding device according to the present invention, a circuit: decodes control information and a quantized value; obtains a decoded transform coefficient by performing inverse quantization on the decoded quantized value; obtains a decoded prediction residual by performing inverse transform on the decoded transform coefficient; generates a first predicted sample based on a decoded sample and the decoded control information; accumulates the decoded sample; generates a second predicted sample based on the accumulated decoded sample and the decoded control information; generates a third predicted sample by weighted averaging using one of weighting coefficients limited based on the decoded control information for at least one of the first predicted sample or the second predicted sample; and obtains the decoded sample by adding the decoded prediction residual and the third predicted sample.

Abstract: In an image decoding device (200) according to the present invention, a circuit: decodes control information and a quantized value; obtains a decoded transform coefficient by performing inverse quantization on the decoded quantized value; obtains a decoded prediction residual by performing inverse transform on the decoded transform coefficient; generates a first predicted sample based on a decoded sample and the decoded control information; accumulates the decoded sample; generates a second predicted sample based on the accumulated decoded sample and the decoded control information; generates a third predicted sample by weighted averaging using weighting coefficients which are uniquely selected from among a plurality of weighting coefficients based on indirect control information for at least one of the first predicted sample or the second predicted sample; and obtains the decoded sample by adding the decoded prediction residual and the third predicted sample.

Abstract: An image decoding device according to the present invention includes a circuit and a buffer, wherein the circuit executes: a first process that derives motion information for a geometric partitioning mode to generate a motion compensation sample; and a second process that derives an intra prediction mode for the geometric partitioning mode to generate an intra predicted sample, the buffer that stores or outputs prediction information including motion information or an intra prediction mode of a coding block to which the geometric partitioning mode is applied, and a prediction type capable of determining whether inter prediction or intra prediction is applied, the first process: controls whether or not to derive motion information by bi-prediction on a basis of a predetermined condition, generates the motion compensation sample using the derived motion information, and stores the motion information in the buffer.

Abstract: In an image decoding device (200) according to the present invention, a circuit: decodes control information and a quantized value; obtains a decoded transform coefficient by performing inverse quantization on the decoded quantized value; obtains a decoded prediction residual by performing inverse transform on the decoded transform coefficient; generates a first predicted sample based on a decoded sample and the decoded control information; accumulates the decoded sample; generates a second predicted sample based on the accumulated decoded sample and the decoded control information; prepares a plurality of weighting coefficients by which a width of a division boundary is different for at least one of the first predicted sample or the second predicted sample, and generates a third predicted sample in which the width of the division boundary is controlled by weighted averaging; and obtains the decoded sample by adding the decoded prediction residual and the third predicted sample.

Abstract: An image decoding device includes a circuit, wherein the circuit applies overlapped block motion compensation to a sub-block facing a block boundary of a block to be decoded to which a geometric partitioning mode including inter prediction or intra prediction is applied.

Abstract: An image decoding device according to the present invention includes a circuit, wherein the circuit controls decoding of syntax that specifies whether or not merge with motion vector difference is applied to a partitioned region 0, which is partitioned in a geometric partitioning mode of a decoding target block, in accordance with a value of syntax that specifies whether or not a prediction mode of the partitioned region 0 is an intra prediction mode.

Abstract: In an image decoding device according to the present invention, a merge candidate in a merge list of the normal merge mode is configured to be generated and stored by a spatial merge candidate, a temporal merge candidate, a non-adjacent merge candidate, a history merge candidate, a pairwise merge candidate, or a zero merge candidate, and a decoding unit (210) is configured to specify the merge candidate from zeroth to fourth merge candidates in the merge list based on syntax (mmvd_cand_idx) transmitted from an image encoding device (100).

Abstract: In an image decoding device according to the present invention, a circuit (241/242): derives motion information for a geometric partitioning mode to generate a motion compensation sample; and derives an intra prediction mode for the geometric partitioning mode to generate an intra-predicted sample; and a buffer (244) stores or outputs prediction information including motion information or an intra prediction mode of a block to be decoded to which the geometric partitioning mode is applied and a prediction type with which whether inter prediction or intra prediction has been applied can be determined.

Abstract: An image decoding device includes a decoding unit configured to decode a first syntax for controlling possibility of application of a geometric partitioning mode of a decoding target sequence, and to control whether to decode a second syntax for controlling possibility of application of an intra prediction mode to the geometric partitioning mode of the decoding target sequence according to a value of the first syntax.

Abstract: An image decoding device includes: a prediction signal generation unit that generates a prediction signal by intra prediction, wherein in a block to which intra sub-partitions are applied, the prediction signal generation unit refers to a pixel of a decoded block adjacent to the block when generating prediction signals of all sub-blocks in the block.

Abstract: An image decoding device (200) includes: an inverse transform unit (220B/220C) configured to generate a prediction residual signal by inverse transform, the inverse transform unit (220B/220C) is configured to control a method of decoding a secondary transform index of a target block according to information indicating a position where a non-zero coefficient is generated in the target block.

Abstract: An image decoding device (200) includes: a merge unit (241A2) configured to apply geometric block partitioning merge to a target block divided in a rectangular shape, wherein the merge unit (241A2) includes: a merge mode specifying unit (241A21) configured to specify whether or not the geometric block partitioning merge is applied; a geometric block partitioning unit (241A22) configured to specify a geometric block partitioning pattern and further perform geometric block partitioning on the target block divided in the rectangular shape by using the specified geometric block partitioning pattern; and a merge list construction unit (241A23) configured to construct a merge list for the target block subjected to the geometric block partitioning and decode motion information.

Abstract: An image decoding device according to the present invention including a decoding unit configured to decode first syntax that controls transmission precision of a merge with motion vector difference in a sequence of a decoding target, wherein the value of the first syntax being “1” specifies that both fractional precision and integer precision could be used as the transmission precision of the merge with motion vector difference in the sequence of the decoding target, and the value of the first syntax being “0” specifies that the first syntax uses fractional precision as the transmission precision of a merge with motion vector difference in the sequence of the decoding target.