A method of video processing is provided. The method includes: determining, for a conversion between a current video block of a video and a coded representation of the video, a mode of operation of an UMVE mode; and performing the conversion based on the determining, wherein the current video block is coded with an affine merge mode and motion vector differences in the affine UMVE mode, and wherein one or more fields in the coded representation correspond to the mode of operation, and wherein the one or more fields include: a list size field that indicates a size of a base affine merge candidate list for an affine merge mode with prediction offsets that is used by the UMVE mode, or a table field that signals a distance table or a direction table for the affine merge mode with prediction offsets.

A video codec can involve encoding and decoding picture information and first and second flags, wherein the encoding or decoding of the picture information is based on a coding mode indicated by the first flag or the second flag, and the first flag indicates a subblock merge mode and the second flag indicates an inter affine prediction mode, and the encoding or decoding of the first flag uses CABAC coding based on a first probability model and encoding or decoding of the second flag uses CABAC coding based on a second probability model.

An image encoding/decoding method and apparatus are provided. An image decoding method includes obtaining inter prediction information of a current block and wraparound information from a bitstream, and generating a prediction block of the current block based on the inter prediction information and the wraparound information. The wraparound information may include a first flag specifying whether wraparound motion compensation is enabled for a current video sequence including the current block. The first flag may have a first value specifying that the wraparound motion compensation is disabled, based on that one or more subpicture, which is coded independently and has a width different from a width of a current picture, is present in the current video sequence.

An image encoding/decoding method and apparatus are provided. An image decoding method includes obtaining inter prediction information of a current block and wraparound information from a bitstream, and generating a prediction block of the current block based on the inter prediction information and the wraparound information. The wraparound information may include a first flag specifying whether wraparound motion compensation is enabled for a current video sequence including the current block. The first flag may have a first value specifying that the wraparound motion compensation is disabled, based on that one or more subpicture, which is coded independently and has a width different from a width of a current picture, is present in the current video sequence.

An example device for coding point cloud data includes a memory configured to store point cloud data; and one or more processors implemented in circuitry and configured to: determine whether inter prediction data is coded for a current node of an octree of the point cloud data; determine whether planar mask data is coded for the current node; when at least one of the inter prediction data or the planar mask data is coded for the current node, avoid coding a single occupancy value for the current node, the single occupancy value indicating whether only a single sub-node of the current node includes a point; and code the current node. The processors may also be configured to determine a context for entropy coding the planar mask data according to planar mask data for a collocated node in a reference frame when the planar mask data is coded.

An example device for coding point cloud data includes a memory configured to store point cloud data; and one or more processors implemented in circuitry and configured to: determine whether inter prediction data is coded for a current node of an octree of the point cloud data; determine whether planar mask data is coded for the current node; when at least one of the inter prediction data or the planar mask data is coded for the current node, avoid coding a single occupancy value for the current node, the single occupancy value indicating whether only a single sub-node of the current node includes a point; and code the current node. The processors may also be configured to determine a context for entropy coding the planar mask data according to planar mask data for a collocated node in a reference frame when the planar mask data is coded.

Methods are provided for inter-prediction candidate index coding independent of the construction of the corresponding inter-prediction candidate list, i.e., a merging candidate list or an advanced motion vector predictor list. A maximum allowed number of inter-prediction candidates for an inter-prediction candidate list is used for encoding the inter-prediction candidate index in an encoded bit stream. The maximum allowed number may be pre-determined or may be selected by the encoder and encoded in the bit stream. A decoder may then decode the index using the maximum allowed number of inter-prediction candidates independent of the construction of the corresponding inter-prediction candidate list.

Methods are provided for inter-prediction candidate index coding independent of the construction of the corresponding inter-prediction candidate list, i.e., a merging candidate list or an advanced motion vector predictor list. A maximum allowed number of inter-prediction candidates for an inter-prediction candidate list is used for encoding the inter-prediction candidate index in an encoded bit stream. The maximum allowed number may be pre-determined or may be selected by the encoder and encoded in the bit stream. A decoder may then decode the index using the maximum allowed number of inter-prediction candidates independent of the construction of the corresponding inter-prediction candidate list.

Devices, systems and methods for constructing low-complexity non-adjacent merge candidates are described. In a representative aspect, a method for video processing includes receiving a current block of video data, selecting, based on a rule, a first non-adjacent block that is not adjacent to the current block, constructing a first merge candidate comprising motion information based on the first non-adjacent block, identifying a second non-adjacent block that is not adjacent to the current block and different from the first non-adjacent block, based on determining that the second non-adjacent block fails to satisfy the rule, refraining adding a second merge candidate derived from the second non-adjacent block, constructing a merge candidate list based on the first non-adjacent block, and decoding the current block based on the merge candidate list.

A method of visual media processing includes determining whether to use an affine adaptive motion vector resolution (AMVR) technique on visual media data relying on a control information related to the affine AMVR technique in a bitstream representation of the visual media data, wherein the control information is included or excluded from the bitstream representation based on a rule; and performing a conversion between the visual media data and the bitstream representation of the visual media data.