According to disclosure of the present document, an LMCS procedure can be used for blocks having various block tree structures, and memories used in the LMCS procedure can be reduced (limited).

According to disclosure of the present document, an LMCS procedure can be used for blocks having various block tree structures, and memories used in the LMCS procedure can be reduced (limited).

A coding tool set enablement scheme allows one or more coding tools to be used in the encoding or decoding of video data based on one or more characteristics related to the video. In one embodiment, some coding tools are enabled for block sizes below a particular threshold. In another embodiment, a group of coding tools are enabled based on one flag for blocks having a particular characteristic. In another embodiment, these flags are included in a bitstream with the video. In another embodiment, at least one of the flags are inferred to enable some coding tools.

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.

A video decoding method according to the present disclosure includes the steps of: generating a merge candidate list for a current block; determining a merge candidate for the current block among merge candidates included in the merge candidate list; deriving an offset vector for the current block; and deriving a motion vector for the current block by adding the offset vector to a motion vector of the merge candidate.

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video decoding includes receiving circuitry and processing circuitry. For example, the processing circuitry decodes prediction information of a current block in a current picture from a coded video bitstream. The prediction information is indicative of an inter prediction mode with a potential usage of a refinement technique based on a first reference picture and a second reference picture. Then, the processing circuitry determines whether a first equal weighting condition of chroma components from the first reference picture and the second reference picture is satisfied. In response to a failure to satisfy the first equal weighting condition of the chroma components from the first reference picture and the second reference picture, the processing circuitry disables the refinement technique in a reconstruction of a sample in the current block.

A video decoding method includes determining, based on an area of a current block, whether a multi-prediction combination mode for predicting the current block by combining prediction results obtained according to a plurality of prediction modes is applied to the current block, when the multi-prediction combination mode is applied to the current block, determining the plurality of prediction modes to be applied to the current block, generating a plurality of prediction blocks of the current block, according to the plurality of prediction modes, and determining a combined prediction block of the current block, by combining the plurality of prediction blocks according to respective weights.

A video coding or decoding method includes using history-based motion vector prediction (HMVP) for conversion between multiple video blocks including a current block of video and a bitstream representation of the multiple video blocks such that for a uni-predicted block that for which a single reference picture is used for motion compensation, refraining from updating a look-up table for HMVP candidates for the uni-predicted block. The video coding or decoding method further includes performing the conversion using look-up tables for the multiple video blocks.

A video coding or decoding method includes using history-based motion vector prediction (HMVP) for conversion between multiple video blocks including a current block of video and a bitstream representation of the multiple video blocks such that for a uni-predicted block that for which a single reference picture is used for motion compensation, refraining from updating a look-up table for HMVP candidates for the uni-predicted block. The video coding or decoding method further includes performing the conversion using look-up tables for the multiple video blocks.

Apparatus for video decoding includes processing circuitry that decodes prediction information of a current block in a current picture from a coded video bitstream. The prediction information indicates an inter prediction mode. The processing circuitry determines one of decoder-side motion vector refinement (DMVR) and a bi-directional optical flow (BDOF) is enabled based on whether (i) weighted prediction is applied for luma components of the current block and (ii) weighted prediction is applied for chroma components of the current block. The processing circuitry reconstructs a sample in the current block based on whether the one of the DMVR and the BDOF is determined as enabled. The one of the DMVR and the BDOF is disabled responsive to at least one of (i) the weighted prediction being applied for the luma components of the current block and (ii) the weighted prediction being applied for the chroma components of the current block.