Various embodiments for calculating a motion vector predictor for decoding a motion vector of a current block are provided. The motion vector is selected from a candidate list. When a motion vector used for coding a first block spatially adjacent to the current block in a current picture is useable for coding the current block, one or more first candidates is added to the candidate list based on the motion vector used for coding the first block. A second candidate is added to the candidate list based on a motion vector used for coding a second block within a first collocated picture. When a total number of available candidates in the candidate list is less than a predetermined number, a third candidate is added to the candidate list based on a motion vector used for coding a third block within a second collocated picture.

A method of visual media processing includes determining whether to use an affine adaptive motion vector resolution (AMVR) technique on visual media data relying on a control information related to the affine AMVR technique in a bitstream representation of the visual media data, wherein the control information is included or excluded from the bitstream representation based on a rule; and performing a conversion between the visual media data and the bitstream representation of the visual media data.

A method of visual media processing includes determining whether to use an affine adaptive motion vector resolution (AMVR) technique on visual media data relying on a control information related to the affine AMVR technique in a bitstream representation of the visual media data, wherein the control information is included or excluded from the bitstream representation based on a rule; and performing a conversion between the visual media data and the bitstream representation of the visual media data.

An image decoding method according to the present document may comprise the steps of: deriving an inter prediction mode from encoded information; configuring reference picture lists, deriving motion information comprising reference picture indexes for symmetric motion vector differences (SMVD); and generating prediction samples on the basis of the motion information, wherein the reference picture indexes for SMVD can be derived on the basis of short-term reference pictures included within the reference picture lists.

An image decoding method according to the present document may comprise the steps of: deriving an inter prediction mode from encoded information; configuring reference picture lists, deriving motion information comprising reference picture indexes for symmetric motion vector differences (SMVD); and generating prediction samples on the basis of the motion information, wherein the reference picture indexes for SMVD can be derived on the basis of short-term reference pictures included within the reference picture lists.

An image decoding method and apparatus according to an embodiment may extract, from a bitstream, a quantization coefficient generated through core transformation, secondary transformation, and quantization; generate an inverse-quantization coefficient by performing inverse quantization on the quantization coefficient; generate a secondary inverse-transformation coefficient by performing secondary inverse-transformation on a low frequency component of the inverse-quantization coefficient, the secondary inverse-transformation corresponding to the secondary transformation; and perform core inverse-transformation on the secondary inverse-transformation coefficient, the core inverse-transformation corresponding to the core transformation.

An image decoding method and apparatus according to an embodiment may extract, from a bitstream, a quantization coefficient generated through core transformation, secondary transformation, and quantization; generate an inverse-quantization coefficient by performing inverse quantization on the quantization coefficient; generate a secondary inverse-transformation coefficient by performing secondary inverse-transformation on a low frequency component of the inverse-quantization coefficient, the secondary inverse-transformation corresponding to the secondary transformation; and perform core inverse-transformation on the secondary inverse-transformation coefficient, the core inverse-transformation corresponding to the core transformation.

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video decoding includes processing circuitry that decodes prediction information for a plurality of first blocks in a current coded picture that is a part of a coded video sequence. The prediction information indicates that the plurality of first blocks is coded in a local illumination compensation (LIC) mode. The processing circuitry selects a neighboring region for each of the plurality of first blocks. The selected neighboring region and the respective first block form a second block. The processing circuitry performs an inter prediction for the plurality of second blocks in parallel. The processing circuitry determines a set of LIC parameters for each of the plurality of first blocks based on the selected neighboring region of the respective first block and reconstructs the plurality of first blocks based on the sets of LIC parameters.

A system and method for video compression divides colors of all pixel points of a target video frame into R, G, and B values, and all pixels are placed in a three-dimensional coordinate system to establish a correspondence between each pixel point and the coordinate position. Fuzzy recombination and division are performed on all pixel blocks and pixel points with similar RGB values are divided into pixel blocks to obtain a first target pixel block. Pixel blocks with same RGB values but with coordinates which are not close to the first target pixel block are extracted and divided to obtain a second target pixel block. An area enveloping the second target pixel block is extracted, and vector changes of all dynamic pixel points on the enveloping line are traversed and analyzed to determine a minimum compression change block for compression process.

A system and method for video compression divides colors of all pixel points of a target video frame into R, G, and B values, and all pixels are placed in a three-dimensional coordinate system to establish a correspondence between each pixel point and the coordinate position. Fuzzy recombination and division are performed on all pixel blocks and pixel points with similar RGB values are divided into pixel blocks to obtain a first target pixel block. Pixel blocks with same RGB values but with coordinates which are not close to the first target pixel block are extracted and divided to obtain a second target pixel block. An area enveloping the second target pixel block is extracted, and vector changes of all dynamic pixel points on the enveloping line are traversed and analyzed to determine a minimum compression change block for compression process.