A method for decoding a picture from a bitstream. The picture comprising a number of units, and the picture being partitioned into a number of spatial segments by a partition structure. The method includes decoding one or more code words in the bitstream; determining that the partition structure is uniform based on the one or more code words; determining the number of spatial segments based on the one or more code words; determining a segment unit size; and deriving the sizes and/or locations for spatial segments in the picture from the one or more code words. Deriving the sizes and/or locations for spatial segments in the picture comprises a first loop over the number of spatial segments in a first dimension or direction. A number of remaining segment units in the first dimension or direction to be segmented is calculated inside the first loop.

A method of processing video data. The method includes selecting an in-loop filter from a plurality of neural network (NN) filter model candidates, wherein the plurality of NN filter model candidates are based on a reconstructed quality level of a video unit, and performing a conversion between a video media file comprising the video unit and a bitstream based on the in-loop filter selected. A corresponding video coding apparatus and non-transitory computer readable medium are also disclosed.

A video decoding method according to the present document comprises a step of deriving a modified transform coefficient, and the step of deriving the transform coefficient may comprise the steps of: determining whether an LFNST can be applied to the height and width of a current block on the basis of the tree type and color format of the current block; parsing an LFNST index if the LFNST can be applied; and deriving the modified transform coefficient on the basis of the LFNST index and an LFNST matrix.

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video decoding includes processing circuitry. The processing circuitry determines an initial block vector for predicting a current block in a current coding tree unit (CTU) in response to the current block being predicted in an intra block copy (IBC) mode. The processing circuitry performs template matching based on the initial block vector to determine a refined block vector that points to a reference block in a same picture as the current block, and reconstructs the current block based on the reference block.

A method of video processing is described. The method includes determining, for a conversion between a video region of a video and a coded representation of the video, an intra coding characteristic of the video region based on a color format of the video according to a rule; and performing the conversion according to the intra coding characteristic.

A method, device, and non-transitory computer-readable medium for decoding an encoded video bitstream using at least one processor, including, obtaining from the encoded video bitstream a first flag indicating that reference picture resampling is enabled for coded video sequence (CVS); determining a value of a second flag indicating whether a picture resolution is changed in the CVS; based on the value of the second flag indicating that the picture resolution is changed in the CVS, decoding the CVS using the reference picture resampling for spatial scalability and adaptive resolution change (ARC); and based on the value of the second flag indicating that the picture resolution is not changed in the CVS, decoding the CVS using the reference picture resampling for the spatial scalability, and without using the reference picture resampling for the ARC.

A method of video processing includes performing a conversion between a video unit of a video and a coded representation of the video using at least a video picture. Only one of a subpicture coding mode or a resolution-changing coding mode is enabled for the video unit. The subpicture coding mode is a mode in which the video picture is divided into multiple subpictures, and the resolution-changing coding mode is a mode in which a resolution of the video picture is adjusted during the conversion.

Control over encoding of a quantization parameter is appropriately enabled with not only square sub-blocks but also rectangular sub-blocks by using a quantization control size adaptively according to a shape of sub-blocks, with the result that coding efficiency is improved.

Methods, systems, apparatus for video processing are described. The processing may include encoding, decoding or transcoding. One example video processing method includes performing a conversion between a video and a bitstream of the video according to a rule, and wherein the rule specifies that a syntax field is included to specify whether a reference picture list information is present or not in a video unit level of an instantaneous decoding refresh picture.

In an image processing device (i.e. encoder or decoder), the number of loop filter stages is lowered by combining bilateral loop filtering (or Hadamard loop filtering) with either sample Adaptive Offset Filtering (SAO) or Adaptive Loop Filtering (ALF). This avoids the implementation problems associated with too many loop filter stages and provides approximately the same compression efficiency gain as having separate loop filter stages.