CPC H04N 19/132 (2014.11) [H04N 19/105 (2014.11); H04N 19/11 (2014.11); H04N 19/124 (2014.11); H04N 19/136 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/593 (2014.11); H04N 19/70 (2014.11); H04N 19/80 (2014.11)] | 15 Claims |
1. A method for processing video data, comprising:
determining, for a conversion between a chroma block of a video and a bitstream of the video, a parameter of a cross-component linear model for the chroma block according to a rule; and
performing the conversion based on the determining,
wherein the rule specifies that the parameter of the cross-component linear model is determined based on neighbouring chroma samples of the chroma block and down-sampled collocated luma samples derived based on variables representing neighbouring luma samples of a luma block corresponding to the chroma block,
wherein the rule further specifies that when a color format of the chroma block is 4:2:0, the down-sampled collocated luma samples is derived further based on at least one of a value of a first syntax element and a value of a first variable, wherein the first syntax element is included in the bitstream indicating whether chroma sample positions are vertically shifted relative to corresponding luma sample position, and the first variable indicates whether the chroma block locates at a boundary of a coding tree unit comprising the chroma block,
wherein the rule further specifies that when the color format of the chroma block is 4:2:2, the down-sampled collocated luma samples is derived without considering the value of the first syntax element,
wherein the rule further specifies that when the value of the first variable indicates that the chroma block locates at the boundary of the coding tree unit comprising the chroma block, the down-sampled collocated luma samples is derived using a same filter, regardless of the value of the first syntax element, for the chroma block having the color format of 4:2:0 and the chroma block having the color format of 4:2:2, and
wherein the rule further specifies that when the value of the first variable indicates that the chroma block does not locate at the boundary of the coding tree unit comprising the chroma block and the color format of the chroma block is 4:2:0, the down-sampled collocated luma samples are obtained using different filters in response to the first syntax element having different values.
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