Selective use of adaptive in-loop color-space transform and other video coding tools
A method of video processing is provided. The method includes: determining, for a conversion between a current video unit of a video and a coded representation of the video, that applicability of a first coding tool and a second coding tool is mutually exclusive; and performing the conversion based on the determining, wherein the first coding tool corresponds to an adaptive color space transformation (ACT) tool; wherein use of the ACT tool comprises: converting, during encoding, a representation of a visual signal from a first color domain to a second color domain, or converting, during decoding, a representation of a visual signal from the second color domain to the first color domain.
1. A method of processing video data, comprising:
making a first determination, for a conversion between a current video unit of a video and a bitstream of the video, that applicability of a first coding mode and a second coding mode is mutually exclusive, wherein, for an encoding operation, the first coding mode converts visual signals from a first color domain to a second color domain, or for a decoding operation, the first coding mode converts the visual signals from the second color domain to the first color domain; and
performing the conversion based on the first determination;
wherein when the first coding mode is enabled, a third coding mode is allowed to be enabled for a luma component of the current video unit and disabled for a chroma component of the current video unit;
wherein in the third coding mode, differences between quantized residuals derived with an intra prediction and predictors of the quantized residuals are presented in the bitstream.
2. The method of claim 1 , further comprising:
making a second determination, for the conversion, whether the first coding mode is applied to the current video unit based on a tree partitioning structure used for the current video unit; and
performing the conversion further based on the second determination.
3. The method of claim 2 , wherein the first coding mode is not applied for the current video unit when a chroma component and a luma component have different partitioning structures for the current video unit.
4. The method of claim 2 , wherein usage of the first coding mode is conditionally included in the bitstream based on the tree partitioning structure used for the current video unit.
5. The method of claim 4 , wherein a single syntax element that indicates usage of the first coding mode is not included in the bitstream when a chroma component and a luma component have different partitioning structures for the current video unit.
6. The method of claim 4 , wherein signalling of indication of usage of the first coding mode is skipped when a chroma component and a luma component have different partitioning structures for the current video unit.
7. The method of claim 1 , wherein when the first coding mode is enabled for the current video unit, the second coding mode is disabled for the current video unit, or when the second coding mode is enabled for the current video unit, the first coding mode is disabled for the current video unit.
8. The method of claim 7 , wherein the second coding mode uses a linear mode to derive prediction values of a chroma component of the current video unit from a luma component of the current video unit.
9. The method of claim 7 , wherein the second coding mode splits the current video unit into multiple sub-regions, and the multiple sub-regions share a same intra mode.
10. The method of claim 7 , wherein when the first coding mode is enabled, a fourth coding mode is enabled both for a luma component and a chroma component of the current video unit.
11. The method of claim 10 , wherein the fourth coding mode uses a piecewise linear mode to map a luma component between different domains, and a scaling coefficient derived based on reconstructed luma samples to scale a chroma residue.
12. The method of claim 10 , wherein the fourth coding mode splits a transform region into multiple transform sub-regions and only one transform sub-region has a non-zero residual sample, and wherein a size of the transform sub-region having the non-zero residual sample is smaller than or equal to other transform sub-regions.
13. The method of claim 1 , wherein in the third coding mode, prediction samples are derived by performing a boundary down-sampling operation on reference samples based on a size of the current video unit, followed by a matrix vector multiplication operation, and selectively followed by an up-sampling operation.
14. The method of claim 1 , wherein the conversion includes encoding the current video unit into the bitstream.
15. The method of claim 1 , wherein the conversion includes decoding the current video unit from the bitstream.
16. 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:
determining, for a conversion between a current video unit of a video and a bitstream of the video, that applicability of a first coding mode and a second coding mode is mutually exclusive, wherein, for an encoding operation, the first coding mode converts visual signals from a first color domain to a second color domain, or for a decoding operation, the first coding mode converts the visual signals from the second color domain to the first color domain; and
performing the conversion based on the determining;
wherein when the first coding mode is enabled, a third coding mode is allowed to be enabled for a luma component of the current video unit and disabled for a chroma component of the current video unit;
wherein in the third coding mode, differences between quantized residuals derived with an intra prediction and predictors of the quantized residuals are presented in the bitstream.
17. A non-transitory computer-readable storage medium storing instructions that cause a processor to:
determining, for a conversion between a current video unit of a video and a bitstream of the video, that applicability of a first coding mode and a second coding mode is mutually exclusive, wherein, for an encoding operation, the first coding mode converts visual signals from a first color domain to a second color domain, or for a decoding operation, the first coding mode converts the visual signals from the second color domain to the first color domain; and
performing the conversion based on the determining;
wherein when the first coding mode is enabled, a third coding mode is allowed to be enabled for a luma component of the current video unit and disabled for a chroma component of the current video unit;
wherein in the third coding mode, differences between quantized residuals derived with an intra prediction and predictors of the quantized residuals are presented in the bitstream.
18. 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, for a current video unit of the video, that applicability of a first coding mode and a second coding mode is mutually exclusive, wherein, for an encoding operation, the first coding mode converts visual signals from a first color domain to a second color domain, or for a decoding operation, the first coding mode converts the visual signals from the second color domain to the first color domain; and
generating the bitstream based on the determining;
wherein when the first coding mode is enabled, a third coding mode is allowed to be enabled for a luma component of the current video unit and disabled for a chroma component of the current video unit;
wherein in the third coding mode, differences between quantized residuals derived with an intra prediction and predictors of the quantized residuals are presented in the bitstream.