An image decoding method according to the present document comprises the steps of: acquiring inter prediction mode information from encoded information; constructing a motion vector predictor candidate list of a current block on the basis of the inter prediction mode information; deriving a motion vector of the current block on the basis of the motion vector predictor candidate list; and generating prediction samples of the current block on the basis of the motion vector.

Computer processor hardware receives zone information specifying multiple elements of a rendition of a signal belonging to a zone. The computer processor hardware also receives motion information associated with the zone. The motion information can be encoded to indicate to which corresponding element in a reference signal each of the multiple elements in the zone pertains. For each respective element in the zone as specified by the zone information, the computer processor hardware utilizes the motion information to derive a corresponding location value in the reference signal; the corresponding location value indicates a location in the reference signal to which the respective element pertains.

Computer processor hardware receives zone information specifying multiple elements of a rendition of a signal belonging to a zone. The computer processor hardware also receives motion information associated with the zone. The motion information can be encoded to indicate to which corresponding element in a reference signal each of the multiple elements in the zone pertains. For each respective element in the zone as specified by the zone information, the computer processor hardware utilizes the motion information to derive a corresponding location value in the reference signal; the corresponding location value indicates a location in the reference signal to which the respective element pertains.

A video processing method includes generating, for a conversion between a current block of a video and a bitstream representation of the video, a motion vector for the current block; invoking a weighted prediction processing tool or a second processing tool in a mutually exclusive manner; and performing the conversion according to the invoking. The invoking of the second processing tool comprises refining the motion vector.

Provided is a video decoding method including: obtaining a first motion vector indicating a first reference block of a current block in a first reference picture and a second motion vector indicating a second reference block of the current block in a second reference picture; obtaining a parameter related to pixel group unit motion compensation of the current block, based on at least one of information of the parameter related to the pixel group unit motion compensation and a parameter related to an image including the current picture; generating a prediction block by performing, with respect to the current block, block unit motion compensation based on the first motion vector and the second motion vector and performing the pixel group unit motion compensation based on the parameter related to the pixel group unit motion compensation; and reconstructing the current block. Here, a pixel group may include at least one pixel.

Provided is a video decoding method including: obtaining a first motion vector indicating a first reference block of a current block in a first reference picture and a second motion vector indicating a second reference block of the current block in a second reference picture; obtaining a parameter related to pixel group unit motion compensation of the current block, based on at least one of information of the parameter related to the pixel group unit motion compensation and a parameter related to an image including the current picture; generating a prediction block by performing, with respect to the current block, block unit motion compensation based on the first motion vector and the second motion vector and performing the pixel group unit motion compensation based on the parameter related to the pixel group unit motion compensation; and reconstructing the current block. Here, a pixel group may include at least one pixel.

A method for inter-coding video is provided in which transmission bandwidth requirements associated with second motion vectors for bi-directional temporal prediction is reduced. In the method motion vector information for only one of the two motion vectors for bi-directional temporal prediction can be transmitted together with information on how to derive or construct the second motion vector. Thus, rather than sending express information regarding two motion vectors, express information related to only one motion vector along with information related to reconstruction/derivation of the second motion vector is transmitted, thus reducing bandwidth requirements and increasing coding efficiency.

Disclosed is a method for decoding a current block in a current picture included in a high-level layer performed based on a reference picture included in a low-level layer and having a different resolution. A prediction mode for the current block, a decoded residual signal, and decoding information for the current block, are obtained. When the prediction mode is the inter-prediction, a prediction signal for the current block is generated based on the decoding information. A reconstructed block is then generated by adding the prediction signal to the residual signal. Filtering is then performed for correcting the different resolution that is applied to a reference block included in the reference picture such that the different resolution matches a resolution of the current block.

Disclosed is a method for decoding a current block in a current picture included in a high-level layer performed based on a reference picture included in a low-level layer and having a different resolution. A prediction mode for the current block, a decoded residual signal, and decoding information for the current block, are obtained. When the prediction mode is the inter-prediction, a prediction signal for the current block is generated based on the decoding information. A reconstructed block is then generated by adding the prediction signal to the residual signal. Filtering is then performed for correcting the different resolution that is applied to a reference block included in the reference picture such that the different resolution matches a resolution of the current block.

Methods and apparatus for processing of video are described. The processing may include video encoding, decoding, or transcoding. One example video processing method includes performing a conversion between a video including one or more pictures including one or more subpictures and a bitstream of the video. The bitstream conforms to a format rule that specifies that a subpicture cannot be a random access type of subpicture in response to the subpicture not being a leading subpicture of an intra random access point subpicture. The leading subpicture precedes the intra random access point subpicture in output order.