# US 12,113,984 B2 · Motion vector derivation between color components > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,113,984 B2 - Document ID: US12113984B2 - Status: Granted - Kind: B2 - Application number: 17/831,958 - Filed: 2022-06-03 - Published: 2022-09-29 - Granted: 2024-10-08 - Earliest claimed: 2020-01-02 - Assignees: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Applicants: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Inventors: Kai Zhang; Li Zhang; Hongbin Liu; Yue Wang - Web page: https://patentgrep.com/patent/US12113984B2 ## CPC - H04N 19/137: Motion inside a coding unit, e.g. average field, frame or block difference - H04N 19/54: using feature points or meshes - H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction - H04N 19/119: Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/186: the unit being a colour or a chrominance component - H04N 19/52: by predictive encoding - H04N 19/573: Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction - H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method for video processing is provided to comprise: dividing a video block of a first color component to obtain a first set sub-blocks of the first color component; dividing a corresponding video block of a second color component to obtain a second set of sub-blocks of a second color component; deriving one or more motion vectors of the first set of sub-blocks based on one or more motion vectors of the second set of sub-blocks; and performing, based on the one or more motion vectors of the first set and second set of sub-blocks, a conversion between the video block and a coded representation of the video. ## Claims ### Claim 1 A method of processing video data, comprising: determining, during a conversion between a current video unit of a video and a bitstream of the video, that motion vectors of control points for a luma block of the current video unit based on an affine mode, and wherein the current video unit comprises the luma block and a chroma block; dividing the luma block into luma sub-blocks; dividing the chroma block into chroma sub-blocks; determining a luma motion vector for each luma sub-block based on the motion vectors of the control points, and determining a chroma motion vector for each chroma sub-block; and reconstructing the luma block based on the luma motion vector of each luma sub-block; wherein a color format of the current video unit is 4:2:0, the chroma block comprises at least one chroma group, and four chroma sub-blocks included in a same chroma group correspond to four luma sub-blocks; and the four chroma sub-blocks included in the same chroma group share a same chroma motion vector which is derived based two luma motion vectors of two corresponding luma sub-blocks at diagonal or anti-diagonal positions. ### Claim 2 (depends on 1) The method of claim 1, wherein a top-left one of the four luma sub-blocks has motion vector MV0, and a bottom-right one of the four luma sub-blocks has motion vector MV1, and wherein the same chroma motion vector is derived based on applying a scaling factor to an intermediate motion vector MV*, and the MV* is derived based on the MV0 and the MV1. ### Claim 3 (depends on 2) The method of claim 2, wherein the intermediate motion vector MV* is derived based on applying an offset-based averaging operation on the MV0 and the MV1. ### Claim 4 (depends on 3) The method of claim 3, wherein the intermediate motion vector MV*=Shift(MV0+MV1,1), wherein Shift(x,1)=(x+offset)>>1, offset is equal to 0 or 1, and wherein >>represents a right shift operation. ### Claim 5 (depends on 1) The method of claim 1, wherein a number of the control points is 2. ### Claim 6 (depends on 1) The method of claim 1, wherein the control points include a top-left control point and a top-right control point. ### Claim 7 (depends on 1) The method of claim 1, wherein a number of the control points is 3. ### Claim 8 (depends on 1) The method of claim 1, wherein the control points include a top-left control point, a top-right control point and a bottom-left corner control point. ### Claim 9 (depends on 1) The method of claim 1, further comprising: reconstructing the chroma block based on the motion vectors of the chroma sub-blocks. ### Claim 10 (depends on 1) The method of claim 1, wherein the conversion includes encoding the current video unit into the bitstream. ### Claim 11 (depends on 1) The method of claim 1, wherein the conversion includes decoding the current video unit from the bitstream. ### Claim 12 An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to: determine, during a conversion between a current video unit of a video and a bitstream of the video, that motion vectors of control points for a luma block of the current video unit based on an affine mode, and wherein the current video unit comprises the luma block and a chroma block; divide the luma block into luma sub-blocks; divide the chroma block into chroma sub-blocks; determine a luma motion vector for each luma sub-block based on the motion vectors of the control points, and determining a chroma motion vector for each chroma sub-block; and reconstruct the luma block based on the luma motion vector of each luma sub-block; wherein a color format of the current video unit is 4:2:0, the chroma block comprises at least one chroma group, and four chroma sub-blocks included in a same chroma group correspond to four luma sub-blocks; and the four chroma sub-blocks included in the same chroma group share a same chroma motion vector which is derived based two luma motion vectors of two corresponding luma sub-blocks at diagonal or anti-diagonal positions. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein a top-left one of the four luma sub-blocks has motion vector MV0, and a bottom-right one of the four luma sub-blocks has motion vector MV1, and wherein the same chroma motion vector is derived based on applying a scaling factor to an intermediate motion vector MV*, and the MV* is derived based on the MV0 and the MV1. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the intermediate motion vector MV* is derived based on applying an offset-based averaging operation on the MV0 and the MV1. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the intermediate motion vector MV*=Shift (MV0+MV1,1), wherein Shift(x,1)=(x+offset)>>1, offset is equal to 0 or 1, and wherein >>represents a right shift operation. ### Claim 16 (depends on 12) The apparatus of claim 12, wherein a number of the control points is 2. ### Claim 17 (depends on 12) The apparatus of claim 12, wherein the control points include a top-left control point and a top-right control point. ### Claim 18 (depends on 12) The apparatus of claim 12, wherein a number of the control points is 3. ### Claim 19 A non-transitory computer-readable storage medium storing instructions that cause a processor to: determine, during a conversion between a current video unit of a video and a bitstream of the video, that motion vectors of control points for a luma block of the current video unit based on an affine mode, and wherein the current video unit comprises the luma block and a chroma block; divide the luma block into luma sub-blocks; divide the chroma block into chroma sub-blocks; determine a luma motion vector for each luma sub-block based on the motion vectors of the control points, and determining a chroma motion vector for each chroma sub-block; and reconstruct the luma block based on the luma motion vector of each luma sub-block; wherein a color format of the current video unit is 4:2:0, the chroma block comprises at least one chroma group, and four chroma sub-blocks included in a same chroma group correspond to four luma sub-blocks; and the four chroma sub-blocks included in the same chroma group share a same chroma motion vector which is derived based two luma motion vectors of two corresponding luma sub-blocks at diagonal or anti-diagonal positions. ### Claim 20 A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises: determining, that motion vectors of control points for a luma block of a current video unit of the video based on an affine mode, and wherein the current video unit comprises the luma block and a chroma block; dividing the luma block into luma sub-blocks; dividing the chroma block into chroma sub-blocks; determining a luma motion vector for each luma sub-block based on the motion vectors of the control points, and determining a chroma motion vector for each chroma sub-block; reconstructing the luma block based on the luma motion vector of each luma sub-block to obtain reconstructed luma block; and generating the bitstream at least based on the reconstructed luma block; wherein a color format of the current video unit is 4:2:0, the chroma block comprises at least one chroma group, and four chroma sub-blocks included in a same chroma group correspond to four luma sub-blocks; and the four chroma sub-blocks included in the same chroma group share a same chroma motion vector which is derived based two luma motion vectors of two corresponding luma sub-blocks at diagonal or anti-diagonal positions.