In a method and a device for encoding or decoding an image according to the present invention, motion information for bidirectional prediction of a current block may be derived on the basis of an inter mode previously defined in the device for encoding or decoding an image, and inter prediction may be performed on the current block on the basis of the motion information, wherein the motion information for bidirectional prediction is adjusted to be motion information for unidirectional prediction according to the predefined inter mode.

In a method and a device for encoding or decoding an image according to the present invention, motion information for bidirectional prediction of a current block may be derived on the basis of an inter mode previously defined in the device for encoding or decoding an image, and inter prediction may be performed on the current block on the basis of the motion information, wherein the motion information for bidirectional prediction is adjusted to be motion information for unidirectional prediction according to the predefined inter mode.

A decoding device includes a controller classifying a bitstream as a first bitstream and a second bitstream based on a plurality of blocks defined by a matrix and included in a frame, a first decoder including a first processor performing decoding on the first bitstream and outputting first decoding data and a first memory, a second decoder including a second processor performing decoding on the second bitstream and outputting second decoding data and a second memory, a first buffer transmitting the first decoding data to the second memory, and a second buffer transmitting the second decoding data to the first memory. The first processor controls the second memory to store the first decoding data, and the second processor controls the first memory to store the second decoding data.

A method for processing a video includes performing a conversion between a current block of visual media data and a corresponding coded representation of the visual media data, wherein the conversion of the current block includes determining whether a use of one or both of a bi-directional optical flow (BIO) technique or a decoder-side motion vector refinement (DMVR) technique to the current block is enabled or disabled, and wherein the determining the use of the BIO technique or the DMVR technique is based on a cost criterion associated with the current block.

A video decoder, encoder, and corresponding methods for processing video data for an image block and a particular reference picture index to predict the image block are disclosed that utilize adaptive weighting of reference pictures to enhance video compression, where a decoder includes a reference picture weighting factor unit for determining a weighting factor corresponding to the particular reference picture index; an encoder includes a reference picture weighting factor assignor for assigning a weighting factor corresponding to the particular reference picture index; and a method for decoding includes receiving a reference picture index with the data that corresponds to the image block, determining a weighting factor for each received reference picture index, retrieving a reference picture for each index, motion compensating the retrieved reference picture, and multiplying the motion compensated reference picture by the corresponding weighting factor to form a weighted motion compensated reference picture.

A video decoder, encoder, and corresponding methods for processing video data for an image block and a particular reference picture index to predict the image block are disclosed that utilize adaptive weighting of reference pictures to enhance video compression, where a decoder includes a reference picture weighting factor unit for determining a weighting factor corresponding to the particular reference picture index; an encoder includes a reference picture weighting factor assignor for assigning a weighting factor corresponding to the particular reference picture index; and a method for decoding includes receiving a reference picture index with the data that corresponds to the image block, determining a weighting factor for each received reference picture index, retrieving a reference picture for each index, motion compensating the retrieved reference picture, and multiplying the motion compensated reference picture by the corresponding weighting factor to form a weighted motion compensated reference picture.

Disclosed is a video signal processing method comprising the steps of: acquiring a merge index which indicates a candidate for prediction of a current block among a plurality of candidates for the prediction of the current block, which are included in a merge candidate list; acquiring motion information of the current block on the basis of motion information corresponding to the candidate indicated by the merge index; when the motion information of the current block includes a plurality of motion vectors corresponding to a list of different reference pictures, comparing picture order count (POC) differences between each of the reference pictures corresponding to the plurality of motion vectors and the current picture including the current block; correcting the plurality of motion vectors on the basis of a result of the comparison; and reconstructing the current block on the basis of the plurality of corrected motion vectors.

Disclosed is a video signal processing method comprising the steps of: acquiring a merge index which indicates a candidate for prediction of a current block among a plurality of candidates for the prediction of the current block, which are included in a merge candidate list; acquiring motion information of the current block on the basis of motion information corresponding to the candidate indicated by the merge index; when the motion information of the current block includes a plurality of motion vectors corresponding to a list of different reference pictures, comparing picture order count (POC) differences between each of the reference pictures corresponding to the plurality of motion vectors and the current picture including the current block; correcting the plurality of motion vectors on the basis of a result of the comparison; and reconstructing the current block on the basis of the plurality of corrected motion vectors.

In general, encoding or decoding a picture part can involve determining a spatiotemporal motion vector predictor (STMVP) candidate for a merge mode of operation from spatial motion vector candidates taken from spatial positions around a current coding unit (CU) and a temporal motion vector candidate, where at least one embodiment involves determining the STMVP candidate based on considering at most two spatial positions and based on an average of at least two of the spatial and temporal motion vector candidates.

In some aspects, the disclosure is directed to methods and systems for reducing memory utilization and increasing efficiency during affine merge mode for versatile video coding by utilizing motion vectors stored in a motion data line buffer for a prediction unit of a second coding tree unit neighboring a first coding tree unit to derive control point motion vectors for the first coding tree unit.