According to one embodiment of the present document, a (decoded) picture can be split into sub-pictures. Information related to the sub-pictures can be acquired by means of a decoding device, and a decoding procedure can be performed on the basis of the information related to the sub-pictures. In one embodiment, the decoding device can determine, on the basis of the information about the sub-pictures, the location in which information related to locations of virtual boundaries for in-loop filtering is signaled.

According to one embodiment of the present document, a (decoded) picture can be split into sub-pictures. Information related to the sub-pictures can be acquired by means of a decoding device, and a decoding procedure can be performed on the basis of the information related to the sub-pictures. In one embodiment, the decoding device can determine, on the basis of the information about the sub-pictures, the location in which information related to locations of virtual boundaries for in-loop filtering is signaled.

According to embodiment(s) of the present document, computational overhead and complexity can be reduced by using a 0th-order exponential Golomb coding scheme (ue(v)) for procedures of parsing syntax elements/information about absolute values of luma/chroma ALF filter coefficients. In addition, coding using ue(v) can be efficiently performed by fixing the range of values of the information about the absolute values of the luma/chroma ALF filter coefficients.

According to embodiment(s) of the present document, computational overhead and complexity can be reduced by using a 0th-order exponential Golomb coding scheme (ue(v)) for procedures of parsing syntax elements/information about absolute values of luma/chroma ALF filter coefficients. In addition, coding using ue(v) can be efficiently performed by fixing the range of values of the information about the absolute values of the luma/chroma ALF filter coefficients.

Methods and devices are provided for reducing the decoding latency introduced by LMCS. In one method, during decoding of a coding unit (CU), a plurality of reconstructed luma samples is selected from a first pre-determined region neighboring to a second pre-determined region where the CU is located, an average of the plurality of reconstructed luma samples is calculated, and the average of the plurality of reconstructed luma samples is used directly, without any clipping, in deriving a chroma residual scaling factor for decoding the CU.

Methods and devices are provided for reducing the decoding latency introduced by LMCS. In one method, during decoding of a coding unit (CU), a plurality of reconstructed luma samples is selected from a first pre-determined region neighboring to a second pre-determined region where the CU is located, an average of the plurality of reconstructed luma samples is calculated, and the average of the plurality of reconstructed luma samples is used directly, without any clipping, in deriving a chroma residual scaling factor for decoding the CU.

Methods, devices and systems for video coding and encoding, which include conforming to constraints on collocated pictures, are described. One example method of video processing includes performing a conversion between a video including a current picture and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that the bitstream includes a flag for disabling a use of a temporal motion vector prediction tool for the current picture based on whether a reference picture in a decoded picture buffer has a spatial resolution and a scaling window offset that are identical to that of the current picture.

Methods, devices and systems for video coding and encoding, which include conforming to constraints on collocated pictures, are described. One example method of video processing includes performing a conversion between a video including a current picture and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that the bitstream includes a flag for disabling a use of a temporal motion vector prediction tool for the current picture based on whether a reference picture in a decoded picture buffer has a spatial resolution and a scaling window offset that are identical to that of the current picture.

A down-sample video coding system is provided. A decoding system receives to be decoded data from a bitstream for one or more pictures of a video. Each picture includes pixels having different color components. The decoding system receives up-down-sampling parameters that are applicable to a current video unit in the received data. The up-down-sampling parameters include different subsets for different color components. The decoding system decodes the data to reconstruct the current video unit. The decoding system up-samples the reconstructed current video unit according to the up-down-sampling parameters. The different color components of the current video unit are up-sampled according to different subsets of the up-down-sampling parameters.

A down-sample video coding system is provided. A decoding system receives to be decoded data from a bitstream for one or more pictures of a video. Each picture includes pixels having different color components. The decoding system receives up-down-sampling parameters that are applicable to a current video unit in the received data. The up-down-sampling parameters include different subsets for different color components. The decoding system decodes the data to reconstruct the current video unit. The decoding system up-samples the reconstructed current video unit according to the up-down-sampling parameters. The different color components of the current video unit are up-sampled according to different subsets of the up-down-sampling parameters.