CPC H04N 19/132 (2014.11) [H04N 19/105 (2014.11); H04N 19/117 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/30 (2014.11); H04N 19/80 (2014.11)] | 20 Claims |
1. A method of processing video data, comprising:
determining, for a conversion between a current video block of a video that is a chroma block and a bitstream of the video, a corresponding luma block for the current video block, wherein a color format for the current video block and the corresponding luma block is 4:2:0, and a cross-component linear model is applied for the current video block;
generating down-sampled inside luma samples of the corresponding luma block;
generating down-sampled above neighboring luma samples of the corresponding luma block, wherein different down-sampled filtering schemes are used to generate the down-sampled above neighboring luma samples based on a position of the corresponding luma block, and wherein in response to the position of the corresponding luma block meeting a first position rule, a first down-sampled filtering scheme is used to generate the down-sampled above neighboring luma samples, and wherein the first position rule is that a top boundary of the corresponding luma block is overlapping with a top boundary of a current luma coding tree block (CTB) including the corresponding luma block, and wherein only one above luma sample row and a horizontal 3-tap filter are used to generate the down-sampled above neighboring luma samples in the first down-sampled filtering scheme;
deriving parameters of the cross-component linear model at least based on the down-sampled above neighboring luma samples;
generating predicted chroma samples of the current video block based on the parameters of the cross-component linear model and the down-sampled inside luma samples; and
performing the conversion based on the predicted chroma samples,
wherein the only one above luma sample row is adjacent to the corresponding luma block; and
wherein in response to the position of the corresponding luma block not meeting the first position rule, a second down-sampled filtering scheme is used to generate the down-sampled above neighboring luma samples.
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