Abstract: A video decoding method performed by a decoding apparatus includes the steps of: deriving control points (CP) for a current block; acquiring movement vectors for the CPs; deriving a sample unit movement vector in the current block on the basis of the acquired movement vectors; and deriving a prediction sample for the current block on the basis of the sample unit movement vector. According to the present invention, it is possible to effectively perform, through sample unit motion vectors, inter-prediction not only in a case where an image in the current block is plane-shifted but also in a case where there are various image distortions.

Abstract: A video decoding method comprises: deriving L0 and L1 motion vectors of a current block; deriving decoder-side motion vector refinement (DMVR) flag information indicating whether to apply a DMVR to the current block; when the DMVR flag information indicates that the DMVR is to be applied to the current block, deriving refined L0 and L1 motion vectors based on the L0 and L1 motion vectors by applying the DMVR to the current block; deriving prediction samples of the current block based on the refined L0 and L1 motion vectors; and generating reconstructed samples of the current block based on the predicted samples, wherein deriving DMVR flag information comprises deriving the DMVR flag information by applying the DMVR to the current block when the height of the current block is 8 or more, and when the values of L0 and L1 luma weighted prediction flag information are both 0.

Abstract: According to a disclosure of the present document, when the type of inter-prediction of a current block is indicated as biprediction, weight index information for a candidate within a merge candidate list or a sub-block merge candidate list may be derived, and coding efficiency may be increased.

Abstract: An image decoding method according to the present disclosure includes deriving a history-based motion vector prediction (HMVP) buffer for a current block, deriving motion information of the current block based on an HMVP candidate included in the HMVP buffer, generating prediction samples for the current block based on the motion information, and generating reconstructed samples based on the prediction samples, and the HMVP buffer is initialized when processing a first-ordered CTU in a CTU row in which a current CTU is located, and the current block is included in the current CTU.

Abstract: An image decoding method according to the present document may comprise the steps of: deriving an inter prediction mode from encoded information; configuring reference picture lists, deriving motion information comprising reference picture indexes for symmetric motion vector differences (SMVD); and generating prediction samples on the basis of the motion information, wherein the reference picture indexes for SMVD can be derived on the basis of short-term reference pictures included within the reference picture lists.

Abstract: An image decoding method performed by a decoding apparatus according to the present disclosure includes determining whether to use an advanced temporal motion vector predictor (ATMVP) candidate of sub-block unit for a current block, specifying a corresponding block corresponding to the current block in a reference picture based on a motion vector for a spatial neighboring block of the current block when the ATMVP candidate of the sub-block unit is used, deriving the ATMVP candidate of the sub-block unit for the current block based on motion vectors of sub-block unit of the corresponding block, constructing a merge candidate list including the ATMVP candidate of the sub-block unit for the current block, generating prediction samples of the current block by deriving motion vectors of the sub-block unit for the current block based on the merge candidate list and reconstructing a current picture based on the prediction samples of the current block.

Abstract: An image decoding method according to the present document includes obtaining motion prediction information for a current block from a bitstream, generating an affine MVP candidate list for the current block, deriving CPMVPs for CPs of the current block based on the affine MVP candidate list, deriving CPMVDs for the CPs of the current block based on the motion prediction information, deriving CPMVs for the CPs of the current block based on the CPMVPs and the CPMVDs, and deriving prediction samples for the current block based on the CPMVs.

Abstract: Disclosed are an intra-prediction mode-based image processing method and a device therefor. Particularly, a method for processing an image on the basis of an intra-prediction mode may comprise the steps of: configuring a reference sample to be used for prediction of a current block on the basis of width information and height information of the current block when the current block is a non-square block; deriving an intra-prediction mode of the current block; and generating a prediction sample of the current block by using the reference sample on the basis of the intra-prediction mode of the current block.

Abstract: The present invention discloses a method for encoding/decoding a video signal and an apparatus for the method. More specifically, a method for decoding a video signal comprises generating a residual block of a current block by performing entropy decoding on the video signal; if size of the current block is smaller than a predetermined first size, parsing a transform skip flag which indicates whether a transform skip is applied to the current block; determining whether to parse a primary transform flag which indicates whether a primary transform is applied to the current block; if it is determined to parse the primary transform flag, parsing the primary transform flag; and if the primary transform flag indicates that a primary transform is applied to the current block, generating a primary inverse transformed transform block of the current block by performing a primary inverse transform to the residual block.

Abstract: According to the disclosure of the present document, when the inter prediction type of a current block indicates biprediction, weight index information for candidates in a merge candidate list or a sub-block merge candidate list can be derived, and thus coding efficiency can be increased.

Abstract: A method by which a decoding device performs image decoding, according to the present document, comprises the steps of: deriving a reference block on the basis of a motion shift; determining whether a subblock temporal motion vector predictor (sbTMVP) candidate is available, on the basis of whether the reference block is a current picture referencing (CPR) block; deriving motion information about a current block on the basis of the sbTMVP candidate when the sbTMVP candidate is available; generating prediction samples on the basis of the motion information; and generating a restored picture on the basis of the prediction samples, wherein the sbTMVP candidate is determined to be unavailable with respect to the reference block which is the CPR block.

Abstract: A video processing method according to an embodiment of the present disclosure includes obtaining motion information and bi-directional prediction weight information for inter prediction of a current block, deriving a prediction sample of the current block based on the motion information and the bi-directional prediction weight information, and updating an HMVP candidate list based on a history-based motion vector predictor (HMVP) candidate including the motion information and the bi-directional prediction weight information. The motion information includes a first reference index and a first motion vector related to a first reference picture and a second reference index and a second motion vector related to a second reference picture. The bi-directional prediction weight information may be used to derive a first weight value applied to a first prediction sample from the first reference picture and a second weight value applied to a second prediction sample from the second reference picture.

Abstract: According to the disclosure of the present document, when the inter prediction type of a current block indicates biprediction, weight index information for candidates in a merge candidate list or a sub-block merge candidate list can be induced or derived, and coding efficiency can be increased.

Abstract: An image decoding method includes: deriving an L0 motion vector and a L1 motion vector of the current block; deriving prediction samples of the current block based on the L0 motion vector and the L1 motion vector; and generating reconstructed samples of the current block based on the prediction samples. Deriving the prediction samples includes applying bi-directional optical flow (BDOF) to the current block based on whether the condition for applying BDOF to the current block is satisfied, and the application condition of the BDOF includes a condition whereby the values of L0 luma weighted prediction flag information and L1 luma weighted prediction flag information are both zero, where the a value of each of the L0 luma weighted prediction flag information and L1 luma weighted prediction flag information being 0 represents that a weight factor for each of a L0 and L1 prediction luma components does not exist, respectively.

Abstract: A decoding method performed by a decoding device according to the present document comprises: a step for determining the prediction mode of a current block on the basis of information on a prediction mode acquired from a bitstream; a step for deriving movement information on the current block on the basis of the prediction mode; a step for generating prediction samples of the current block on the basis of the movement information; and a step for generating reconstructed samples on the basis of the prediction samples, wherein the step for determining the prediction mode may include a step for acquiring a regular merge flag from the bitstream on the basis of a combined inter-picture merge and intra-picture prediction (CIIP) available flag that indicates whether or not a CIIP is available.

Abstract: A method for image decoding performed by a decoding apparatus according to the present disclosure comprises the steps of: deriving an ATMVP candidate for a current block; deriving merge candidates for the current block; deriving prediction samples for the current block on the basis of the merge candidates and the ATMVP candidate; and deriving reconstruction samples for the current block on the basis of the prediction samples, wherein the ATMVP candidate is a spatial neighboring block spatially adjacent to the current block.

Abstract: An image decoding method performed by a decoding apparatus includes the operations: deriving a correspondence block corresponding to the current block of the current picture, the correspondence block being located in a co-located picture; deriving a movement vector of the correspondence block; scaling the movement vector of the correspondence block based on a first temporal distance and second temporal distance, the first temporal distance being the difference between the POC values of the co-located picture and POC values of the reference picture of the correspondence block, and the second temporal distance being the difference between the POC values of the co-located picture and POC values of the current picture containing the current block; deriving the movement vector updated based on the scaled movement vector and location of the current block; and deriving a movement vector of the current block based on the updated movement vector.

Abstract: According to an embodiment disclosed in the present document, it is possible to derive a history-based motion vector prediction (HMVP) buffer for a current block based on a history, and to derive motion information of the current block based on an HMVP candidate included in the HMVP buffer, thereby increasing inter prediction efficiency.

Abstract: The present invention relates to a method for encoding and decoding images, wherein, if bi-prediction is applied, a weight for a merge candidate is derived, thereby improving the image compression efficiency, and making it possible to efficiently configure a motion vector candidate. A merge candidate list of the current block is produced on the basis of inter-prediction information, and the candidate includes a configured affine merge candidate. If the configured affine merge candidate is produced on the basis of a combination of control points including CP0, weight index information regarding the configured affine merge candidate is produced on the basis of weight index information regarding CP0. If the configured affine merge candidate is produced on the basis of a combination of control points excluding CP0, weight index information regarding the configured affine merge candidate is derived on the basis of weight index information regarding CP1.

Abstract: An image decoding method performed by a decoding apparatus according to the present disclosure comprises the steps of: decoding, on the basis of a bitstream, an affine flag that indicates whether affine prediction is applicable to a current block and a sub-block TMVP flag that indicates whether a temporal motion vector predictor based on a sub-block of the current block is usable; determining whether to decode a predetermined merge mode flag that indicates whether to apply a predetermined merge mode to the current block, on the basis of the decoded affine flag and the decoded sub-block TMVP flag; deriving prediction samples of the current block on the basis of the determining of whether to decode the predetermined merge mode flag; and generating reconstructed samples of the current block based on the prediction samples of the current block.