Harmonized local illumination compensation and modified inter coding tools
A method for video processing is provided to include: determining, based on an inheritance rule, whether to use a local illumination compensation (LIC) mode for a conversion between a current block of a video region of a video and a coded representation of the video, and performing the conversion based on the determining. The LIC mode includes using a linear model of illumination changes in the current block during the conversion. The inheritance rule specifies to inherit a use of the LIC mode from a base merge candidate of an ultimate motion vector expression (UMVE) mode, and the UMVE mode includes using a motion vector expression that includes a base merge candidate and motion vector differences utilized to refine the motion information of the base merge candidate.
1. A method for video processing, comprising:
determining, based on an inheritance rule, whether to use a local illumination compensation (LIC) mode for a conversion between a current block of a video region of a video and a bitstream of the video, and
determining to use a local illumination compensation (LIC) tool and a sub-block based affine coding mode exclusive of each other, and
determining to use the local illumination compensation (LIC) tool and a triangular prediction mode (TPM) exclusive of each other; and
performing the conversion based on the determining,
wherein the inheritance rule specifies to inherit a use of the LIC mode from a base merge candidate of an ultimate motion vector expression (UMVE) mode, and
wherein the UMVE mode comprises using a motion vector expression that includes a base merge candidate and motion vector differences utilized to refine motion information of the base merge candidate.
2. The method of claim 1 , wherein LIC parameters are derived based on neighboring samples of a current coding unit (CU) of the video.
3. The method of claim 2 , wherein the LIC parameters are derived for blocks on boundaries of the video region that are coded in the UMVE mode.
4. The method of claim 1 , wherein LIC parameters are inherited from the base merge candidate for blocks inside the video region.
5. The method of claim 1 , wherein an LIC flag is signaled explicitly in the UMVE mode.
6. The method of claim 1 , wherein the LIC tool includes using a linear model of illumination changes in the current block during the conversion.
7. The method of claim 1 , wherein the determining determines that the LIC tool is disabled in the conversion due to that the current block is coded with the sub-block based affine coding mode.
8. The method of claim 1 , wherein the TPM includes dividing the video region into at least two non-rectangular portions for the conversion.
9. The method of claim 1 , wherein the determining determines that the triangular prediction mode is enabled and the conversion is performed by disabling the LIC tool.
10. The method of claim 1 , wherein a LIC flag of a TPM merge candidate is inherited from a spatial or temporal block or other motion candidates.
11. The method of claim 10 , wherein the other motion candidates include HMVP (History-based Motion Vector Prediction) candidates.
12. The method of claim 1 , wherein a LIC flag of a TPM merge candidate is inherited from some spatial or temporal blocks.
13. The method of claim 1 , wherein an LIC flag of a TMP merge candidate is set to false.
14. The method of claim 1 , wherein the performing of the conversion includes generating the bitstream from the current block.
15. The method of claim 1 , wherein the performing of the conversion includes generating the current block from the bitstream.
16. An apparatus in a video system comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:
determine, based on an inheritance rule, whether to use a local illumination compensation (LIC) mode for a conversion between a current block of a video region of a video and a bitstream of the video, and
determine to use a local illumination compensation (LIC) tool and a sub-block based affine coding mode exclusive of each other, and
determine to use the local illumination compensation (LIC) tool and a triangular prediction mode (TPM) exclusive of each other; and
perform the conversion based on the determining,
wherein the inheritance rule specifies to inherit a use of the LIC mode from a base merge candidate of an ultimate motion vector expression (UMVE) mode, and
wherein the UMVE mode comprises using a motion vector expression that includes a base merge candidate and motion vector differences utilized to refine motion information of the base merge candidate.
17. The apparatus of claim 16 , wherein LIC parameters are derived based on neighboring samples of a current coding unit (CU) of the video.
18. A non-transitory computer-readable storage medium storing instructions that cause a processor to:
determine, based on an inheritance rule, whether to use a local illumination compensation (LIC) mode for a conversion between a current block of a video region of a video and a bitstream of the video, and
determine to use a local illumination compensation (LIC) tool and a sub-block based affine coding mode exclusive of each other, and
determine to use the local illumination compensation (LIC) tool and a triangular prediction mode (TPM) exclusive of each other; and
perform the conversion based on the determining,
wherein the inheritance rule specifies to inherit a use of the LIC mode from a base merge candidate of an ultimate motion vector expression (UMVE) mode, and
wherein the UMVE mode comprises using a motion vector expression that includes a base merge candidate and motion vector differences utilized to refine motion information of the base merge candidate.
19. 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, based on an inheritance rule, whether to use a local illumination compensation (LIC) mode for a conversion between a current block of a video region of a video and a bitstream of the video, and
determining to use a local illumination compensation (LIC) tool and a sub-block based affine coding mode exclusive of each other, and
determining to use the local illumination compensation (LIC) tool and a triangular prediction mode (TPM) exclusive of each other; and
generating the bitstream based on the determining,
wherein the inheritance rule specifies to inherit a use of the LIC mode from a base merge candidate of an ultimate motion vector expression (UMVE) mode, and
wherein the UMVE mode comprises using a motion vector expression that includes a base merge candidate and motion vector differences utilized to refine motion information of the base merge candidate.
20. The apparatus of claim 17 , wherein the LIC parameters are derived for blocks on boundaries of the video region that are coded in the UMVE mode.