A moving picture decoding apparatus, method, and medium for decoding a current block are provided. A first candidate is derived from a first motion vector that has been used to decode a first block. The first block is adjacent to the current block. A first index identifying a reference picture to be selected for decoding the current block is decoded. A second candidate having a second motion vector that includes a non-zero value is derived. The non-zero value is assigned to the reference picture. A selected candidate is selected from a plurality of candidates, including the first candidate and the second candidate. A second index identifying the selected candidate is decoded. The current block is decoded using the selected candidate. The second candidate includes the non-zero value of the reference picture, with the reference picture being selected from a plurality of referable reference pictures.

A moving picture decoding apparatus, method, and medium for decoding a current block are provided. A first candidate is derived from a first motion vector that has been used to decode a first block. The first block is adjacent to the current block. A first index identifying a reference picture to be selected for decoding the current block is decoded. A second candidate having a second motion vector that includes a non-zero value is derived. The non-zero value is assigned to the reference picture. A selected candidate is selected from a plurality of candidates, including the first candidate and the second candidate. A second index identifying the selected candidate is decoded. The current block is decoded using the selected candidate. The second candidate includes the non-zero value of the reference picture, with the reference picture being selected from a plurality of referable reference pictures.

Obtaining one or more motion vector predictor candidates includes: (a1) generating a motion vector predictor candidate, based on motion vectors of first adjacent blocks adjacent to a block to be processed in a first direction; and (a2) generating a motion vector predictor candidate, based on motion vectors of second adjacent blocks adjacent to the block to be processed in a second direction, and step (a2) includes: determining whether the first adjacent blocks include an inter-predicted block; and searching for a motion vector on which scaling processing can be performed from among the motion vectors of the second adjacent blocks when it is determined that the first adjacent blocks do not include an inter-predicted block, and executing, when the motion vector on which scaling processing can be performed is obtained in the search, scaling processing on the motion vector obtained in the search.

Obtaining one or more motion vector predictor candidates includes: (a1) generating a motion vector predictor candidate, based on motion vectors of first adjacent blocks adjacent to a block to be processed in a first direction; and (a2) generating a motion vector predictor candidate, based on motion vectors of second adjacent blocks adjacent to the block to be processed in a second direction, and step (a2) includes: determining whether the first adjacent blocks include an inter-predicted block; and searching for a motion vector on which scaling processing can be performed from among the motion vectors of the second adjacent blocks when it is determined that the first adjacent blocks do not include an inter-predicted block, and executing, when the motion vector on which scaling processing can be performed is obtained in the search, scaling processing on the motion vector obtained in the search.

A video processing method is disclosed to include: generating one or more initial predictions for a sub-block of a current video block of the video; refining the one or more initial predictions to generate a final prediction block using a prediction refinement with optical flow (PROF) procedure by calculating motion vector differences based on variables having a bit width not exceeding a predetermined maximum bit width; and performing a conversion between the current video block and a coded representation of the video using the variables having the bit width not exceeding the predetermined maximum bit width.

An example video coding device is configured to: code a first set of motion information for a current block of video data partitioned into a first partition and a second partition according to a non-rectangular partition mode, the first set of motion information referring to a reference picture list and being associated with the first partition; after coding the first set of motion information, code a second set of motion information for the current block referring to the reference picture list and that is associated with the second partition; in response to the first set of motion information and the second set of motion information both referring to the reference picture list, store the second set of motion information for the current block; and predict subsequent motion information of a subsequent block of the video data that neighbors the current block using the stored second set of motion information.

A video decoding apparatus is provided. The video decoding apparatus includes a parameter decoding circuit, a prediction parameter derivation circuit, a motion compensation circuit, and a weighted prediction circuit to derive weight coefficients.

A video decoding apparatus is provided. The video decoding apparatus includes a parameter decoding circuit, a prediction parameter derivation circuit, a motion compensation circuit, and a weighted prediction circuit to derive weight coefficients.

Sub-block merge motion field is combined with triangle partitioning and geometric partitioning modes to further give coding and decoding schemes flexibility. In at least one embodiment, a flag is used to signal if sub-block merge candidates are used in place of regular merge candidates. In another embodiment, regular merge candidates are replaced by sub-block merge candidates. In another embodiment, at least one motion field is stored. In another embodiment, all sub-block merge candidates or only sub-block temporal motion vector predictors or only affine predictors are considered.

A motion vector refinement apparatus includes a storage device, a reference block fetch circuit, and a processing circuit. The reference block fetch circuit fetches a forward reference block and a backward reference block according to at least specified motion vectors (MVs) of a current block, and stores the forward reference block and the backward reference block into the storage device. The processing circuit derives a first reference block from the forward reference block and a second reference block from the backward reference block, calculates at least one accumulated pixel difference (APD) value for at least one block pair each having a first block found in the first reference block and a second block found in the second reference block, and determines an offset setting for motion vector refinement of the specified MVs according to the at least one APD value.