CPC H04N 19/186 (2014.11) [H04N 19/119 (2014.11); H04N 19/136 (2014.11); H04N 19/176 (2014.11); H04N 19/52 (2014.11); H04N 19/55 (2014.11)] | 20 Claims |
1. A method of processing video data, comprising:
determining, during a conversion between a current video unit of a video which comprises a luma block and at least one chroma block and a bitstream of the video, that motion vectors of control points for the luma block based on an affine mode;
dividing the luma block into luma sub-blocks, wherein each luma sub-block has a second size;
dividing a chroma block of the at least one chroma block into chroma sub-blocks, wherein each chroma sub-block has a first size;
determining a luma motion vector for each luma sub-block based on the motion vectors of the control points;
deriving a chroma motion vector for each chroma sub-block based on luma motion vectors of multiple luma sub-blocks and a color format of the current video unit; and
reconstructing the luma block based on the luma motion vector of each luma sub-block;
wherein the chroma block comprises at least one first chroma group and the first chroma group includes two or four chroma sub-blocks according to the color format of the current video unit, and wherein motion vectors of the chroma sub-blocks included in the first chroma group are same, and
wherein predicted samples of the chroma block are derived using the chroma sub-blocks having the first size equal to the second size in a case that a color format applied for the luma block and the chroma block is 4:2:0 or 4:2:2.
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