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US 11,902,529 B2Granted
Syntax for signaling cross-component video coding
AssigneesBeijing Bytedance Network Technology Co., Ltd., Bytedance Inc.
InventorsYang Wang, Li Zhang, Kai Zhang, Hongbin Liu, Yue Wang
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Abstract
A method of video processing is provided to include determining, for a conversion between a video block of a video and a bitstream of the video, a parameter of a cross-component linear model (CCLM) for the video block according to a rule, and performing the conversion based on the determining, and wherein the rule specifies to use a variable representing a neighbouring luma sample in the determining of the parameter of the CCLM only in case that the variable has a certain value.
Claims18
A method for processing video data, comprising:
- determining, for a conversion between a first chroma block of a first video picture of a video and a bitstream of the video, that a cross-component linear model (CCLM) prediction mode is applied to the first chroma block,
- determining, a parameter of a CCLM for the first chroma block according to a rule,
- deriving, in the CCLM prediction mode, prediction samples of the first chroma block based on the CCLM and parameters of the CCLM, and
- performing the conversion based on prediction samples of the first chroma block,
- wherein the rule specifies that the parameter of the CCLM is determined based on neirghbouring chroma samples of the first chroma block and first variables representing neighbouring luma samples of a first luma block corresponding to the first chroma block,
- wherein the rule further specifies that the first variables are set equal to neighbouring luma samples of the first luma block when a value of a second variable indicates that a neighbouring block is available and the first variables are set equal to valid samples when the value of the second variable indicates the neighbouring block is not available,
- wherein when the value of the second variable indicates the neighbouring block is available, the first variables denoted as pY [x] [y] are set equal to a reconstructed neighbouring above luma sample prior to a deblocking filter process at a location (xTbY+x, yTbY+y), and a maximum of x is equal to SubWidthC*Max(numSampT, nTbW)−1,
- where (xTbY, yTbY) denotes a top-left position of the first luma block, x and y are integers, nTbW denotes a width of the first chroma block, SubWidthC is a width scale factor obtained according to a chroma format of the first video picture, and numSampT denotes a number of available neighbouring chroma samples in the CCLM prediction mode,
- wherein the neighbouring block indicated by the second variable is a neighbouring chroma block covering a neighbouring above location of the first luma block.
6 more elements
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, for a conversion between a first chroma block of a first video picture of a video and a bitstream of the video, that a cross-component linear model (CCLM) prediction mode is applied to the first chroma block,
- determine, a parameter of a CCLM for the first chroma block according to a rule,
- derive, in the CCLM prediction mode, prediction samples of the first chroma block based on the CCLM and parameters of the CCLM, and
- perform the conversion based on prediction samples of the first chroma block,
- wherein the rule specifies that the parameter of the CCLM is determined based on neirghbouring chroma samples of the first chroma block and first variables representing neighbouring luma samples of a first luma block corresponding to the first chroma block,
- wherein the rule further specifies that the first variables are set equal to neighbouring luma samples of the first luma block when a value of a second variable indicates that a neighbouring block is available and the first variables are set equal to valid samples when the value of the second variable indicates the neighbouring block is not available,
- wherein when the value of the second variable indicates the neighbouring block is available, the first variables denoted as pY [x] [y] are set equal to a reconstructed neighbouring above luma sample prior to a deblocking filter process at a location (xTbY+x, yTbY+y), and a maximum of x is equal to SubWidthC*Max(numSampT, nTbW)−1,
- where (xTbY, yTbY) denotes a top-left position of the first luma block, x and y are integers, nTbW denotes a width of the first chroma block, SubWidthC is a width scale factor obtained according to a chroma format of the first video picture, and numSampT denotes a number of available neighbouring chroma samples in the CCLM prediction mode,
- wherein the neighbouring block indicated by the second variable is a neighbouring chroma block covering a neighbouring above location of the first luma block.
6 more elements
A non-transitory computer-readable storage medium storing instructions that cause a processor to:
- determine, for a conversion between a first chroma block of a first video picture of a video and a bitstream of the video, that a cross-component linear model (CCLM) prediction mode is applied to the first chroma block,
- determine, a parameter of a CCLM for the first chroma block according to a rule,
- derive, in the CCLM prediction mode, prediction samples of the first chroma block based on the CCLM and parameters of the CCLM, and
- perform the conversion based on prediction samples of the first chroma block,
- wherein the rule specifies that the parameter of the CCLM is determined based on neirghbouring chroma samples of the first chroma block and first variables representing neighbouring luma samples of a first luma block corresponding to the first chroma block,
- wherein the rule further specifies that the first variables are set equal to neighbouring luma samples of the first luma block when a value of a second variable indicates that a neighbouring block is available and are set equal to valid samples when the value of the second variable indicates the neighbouring block is not available,
- wherein when the value of the second variable indicates the neighbouring block is available, the first variables denoted as pY [x] [y] are set equal to a reconstructed neighbouring above luma sample prior to a deblocking filter process at a location (xTbY+x, yTbY+y), and a maximum of x is equal to SubWidthC*Max(numSampT, nTbW)−1,
- where (xTbY, yTbY) denotes a top-left position of the first luma block, x and y are integers, nTbW denotes a width of the first chroma block, SubWidthC is a width scale factor obtained according to a chroma format of the first video picture, and numSampT denotes a number of available neighbouring chroma samples in the CCLM prediction mode,
- wherein the neighbouring block indicated by the second variable is a neighbouring chroma block covering a neighbouring above location of the first luma block.
6 more elements
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 a cross-component linear model (CCLM) prediction mode is applied to a first chroma block of a first video picture of the video,
- determining, a parameter of a CCLM for the first chroma block according to a rule,
- deriving, in the CCLM prediction mode, prediction samples of the first chroma block based on the CCLM and parameters of the CCLM, and
- generating the bitstream based on prediction samples of the first chroma block,
- wherein the rule specifies that the parameter of the CCLM is determined based on neirghbouring chroma samples of the first chroma block and first variables representing neighbouring luma samples of a first luma block corresponding to the first chroma block,
- wherein the rule further specifies that the first variables are set equal to neighbouring luma samples of the first luma block when a value of a second variable indicates that a neighbouring block is available and are set equal to valid samples when the value of the second variable indicates the neighbouring block is not available,
- wherein when the value of the second variable indicates the neighbouring block is available, the first variables denoted as pY [x] [y] are set equal to a reconstructed neighbouring above luma sample prior to a deblocking filter process at a location (xTbY+x, yTbY+y), and a maximum of x is equal to SubWidthC*Max(numSampT, nTbW)−1,
- where (xTbY, yTbY) denotes a top-left position of the first luma block, x and y are integers, nTbW denotes a width of the first chroma block, SubWidthC is a width scale factor obtained according to a chroma format of the first video picture, and numSampT denotes a number of available neighbouring chroma samples in the CCLM prediction mode,
- wherein the neighbouring block indicated by the second variable is a neighbouring chroma block covering a neighbouring above location of the first luma block.
6 more elements
Dependencies are inferred from the claim text.