Abstract: Techniques for implementing video processing techniques are described. In one example implementation, a method of video processing includes determining, for a conversion between a current block of a video coded using a combined inter and intra prediction (CIIP) coding technique and a bitstream representation of the video, an intra-prediction mode of the current block independently from an intra-prediction mode of a neighboring block. The CIIP coding technique uses an intermedia inter prediction value and an intermedia intra prediction value to derive a final prediction value of the current block. The method also includes performing the conversion based on the determining.

Abstract: A method for visual media processing includes performing a conversion between a current video unit of a visual media data and a bitstream representation of the current video unit. The bitstream representation is configured according to a format rule. The format rule specifies a level of a video segment at which one or more syntax elements indicative of a scaling factor by which a chroma residual is scaled for coding the current video unit is selectively included in the bitstream representation.

Abstract: Devices, systems and methods for encoding and decoding digital video using a look-up tables (LUTs) containing motion candidates are described. In a representative aspect, a method of video processing includes maintaining one or more tables, wherein at least one table of the one or more tables is associated with one or more entries, deriving, based on a first set of motion candidates in the at least one table, a second set of motion candidates, and performing, based on the second set of motion candidates, a conversion between a current block of a video and a bitstream representation of the video.

Abstract: A method of video processing is provided to include determining, for a conversion between a video block of a video and a bitstream of the video, a parameter of a cross-component linear model (CCLM) for the video block according to a rule, and performing the conversion based on the determining, and wherein the rule specifies to use a variable representing a neighbouring luma sample in the determining of the parameter of the CCLM only in case that the variable has a certain value.

Abstract: A method of video processing is provided to include: performing a conversion between a video including one or more video regions including one or more luma blocks and one or more chroma blocks and a coded representation of the video according to a rule; wherein the rule specifies that a chroma block from the one or more chroma blocks having a size M×N is disallowed to be represented in the coded representation using an intra mode or an intra block copy mode, wherein M and N are integers that indicate a width and a height of the chroma block, respectively; wherein the intra mode includes encoding the chroma block based on previously encoded or reconstructed video blocks, and wherein the intra block copy mode includes encoding the chroma block using at least a block vector pointing to a video frame containing a video region.

Abstract: Devices, systems and methods for sub-block based prediction are described. In a representative aspect, a method for video encoding includes partitioning, based on a first rule, a luma component of a block of video data into a first set of sub-blocks. The method also includes partitioning, based on a second rule, a first chroma component of the block of video data into a second set of sub-blocks. The first and the second set of sub-blocks include different numbers of sub-blocks. The method also includes performing a subsequent motion prediction based on the first and the second set of sub-blocks.

Abstract: Techniques for implementing adaptive loop filtering are described. One example method of video processing includes making a first determination, for a conversion between a video unit of a video and a bitstream of the video, a first luma adaptive loop filter (ALF) boundary across which a luma adaptive loop filter is selectively applied to a luma component of the video unit and a second luma ALF boundary; making a second determination, from the second luma ALF boundary, a chroma ALF boundary across which a chroma adaptive loop filter is selectively applied for a chroma component of the video unit; and performing the conversion based on the first determination and the second determination.

Abstract: Techniques for implementing adaptive loop filtering are described. One example method of video processing includes making a first determination, for a conversion between a video unit of a video and a bitstream of the video, a first luma adaptive loop filter, ALF, boundary across which a luma adaptive loop filter is selectively applied to a luma component of the video unit and a second luma ALF boundary; making a second determination, from the second luma ALF boundary, a chroma ALF boundary across which a chroma adaptive loop filter is selectively applied for a chroma component of the video unit; and performing the conversion based on the first determination and the second determination.

Abstract: A method of video processing is described. The method includes determining, for a conversion between a current video block of a video and a coded representation of the video, whether a certain partitioning scheme is allowed for the current video block according to a rule that depends on a coding mode type used for representing the current video block in the coded representation and a dimension of the current video block; and performing the conversion based on the determining.

Abstract: A method for video processing is provided to include: performing a conversion between a current video block of a video and a coded representation of current video block, wherein the conversion uses a coding mode in which the current video block is constructed based on a first domain and a second domain and/or chroma residue is scaled in a luma-dependent manner, and wherein information used for the coding mode is signaled in a parameter set that is different from a sequence parameter set (SPS), a video parameter set (VPS), a picture parameter set (PPS), or an adaptation parameter set (APS) used for carrying adaptive loop filtering (ALF) parameters.

Abstract: A method of video processing includes determining, for a conversion between a picture of a video that includes one or more blocks and a bitstream representation of the video, whether a virtual boundary is enabled for a block within the picture for a filtering process based on a rule related to a relationship between a bottom boundary of the block and the picture. The method also includes performing the conversion based on the determining.

Abstract: A method of video processing is provided that includes performing a conversion between a block of a video and a bitstream of the video. The bitstream conforms to a formatting rule specifying that a size of a merge estimation region (MER) is indicated in the bitstream and the size of the MER is based on a dimension of a video unit. The MER comprises a region used for deriving a motion candidate for the conversion.

Abstract: Methods, systems, and devices for coding or decoding video wherein the picture partition mode is based on block size are described. An example method for video processing includes using a dimension of a virtual pipeline data unit (VPDU) used for a conversion between a video comprising one or more video regions comprising one or more video blocks and a bitstream representation of the video to perform a determination of whether a ternary-tree (TT) or a binary tree (BT) partitioning of a video block of the one or more video blocks is enabled, and performing, based on the determination, the conversion, wherein the dimension is equal to VSize in luma samples, wherein dimensions of the video block are CtbSizeY in luma samples, wherein VSize=min(M, CtbSizeY), and wherein M is a positive integer.

Abstract: Devices, systems and methods for digital video coding, which include sub-block based inter prediction methods, are described. An exemplary method for video processing includes determining, for a conversion between a current block of video and a bitstream representation of the video, a maximum number of candidates in a sub-block based merge candidate list and/or whether to add sub-block based temporal motion vector prediction (SbTMVP) candidates to the sub-block based merge candidate list based on whether temporal motion vector prediction (TMVP) is enabled for use during the conversion or whether a current picture referencing (CPR) coding mode is used for the conversion, and performing, based on the determining, the conversion.

Abstract: A method of video processing is provided. The method includes: determining, for a conversion between a first video block of a video and a bitstream of the video, that a merge mode with motion vector differences is applied into the first video block; and performing the conversion based on the determining, where the merge mode includes motion vector expression to derive motion information of the first video block, where the motion vector expression includes a first parameter representing a motion vector difference and a second parameter indicating a base candidate from a base candidate list, where the first parameter includes a first motion magnitude and a first motion direction, and where the base candidate list is based on a first merge candidate list for a merge mode which is constructed for the first video block during the conversion.

Abstract: Video processing methods, systems and appratrus are described. One example method includes performing a conversion between a video block of a video and a bitstream of the video using a palette mode in which samples of the video block are represented using a palette of representive color values. A size of the palette of the video block is determined based on whether a local dual tree is applied for the conversion.

Abstract: Methods, systems, and devices related to sub-block based motion prediction in video coding are described. In one representative aspect, a video processing method includes partitioning a video block into a first set of sub-blocks according to a first pattern, partitioning the video block into a second set of sub-blocks according to a second pattern, in which at least one sub-block in the second set has a different size than a sub-block in the first set, and determining a prediction block corresponding to a combination of a first intermediate prediction block that is predictively generated from the first set of sub-blocks and a second intermediate prediction block that is predictively generated from the second set of sub-blocks.

Abstract: A method for regenerating different types of copper-containing aluminum alloys using aluminum alloy scrap from aeronautical industry includes detecting a chemical composition of said aluminum alloy scrap and optionally adding a suitable amount of a metal or alloy additive according to a composition requirement of a target aluminum-copper alloy, thereby obtaining a mixture of aluminum alloy scrap and metal or alloy additive; vacuum smelting the mixture of aluminum alloy scrap and metal or alloy additive in a vacuum furnace, wherein impurities are removed and an aluminum alloy solution is formed; filtering the aluminum alloy solution using a filter to obtain a melt comprising a target aluminum alloy composition; and casting the target aluminum alloy composition from said melt.

Abstract: A method for video processing includes performing a conversion between a current video block of a video and a bitstream representation of the current video block using a matrix based intra prediction (MIP) mode, where the conversion includes performing the upsampling operation in which the final prediction block is determined by using a reduced prediction block of the current video block and by using reconstructed neighboring samples of the current video block according to a rule, and where the reduced prediction block is obtained by performing the matrix vector multiplication operation on reduced boundary samples of the current video block.

Abstract: A video processing method for efficient affine merge motion vector derivation is disclosed. In one aspect, a video processing method is provided to include partitioning a current video block into sub-blocks; deriving, for each sub-block, a motion vector, where the motion vector for each sub-block is associated with a position for that sub-block according to a position rule; and processing a bitstream representation of the current video block using motion vectors for the sub-blocks.