Intra block copy with triangular partitions

1. A method of processing video data, comprising:

making a determination, for a conversion between a block of a video and a bitstream of the block, that an intra block copy (IBC) mode is applied to multiple sub-regions of the block, wherein the block is split into two or multiple triangular or wedgelet sub-regions; and

performing the conversion based on the determination,

wherein, in the IBC mode, prediction samples are derived from blocks of sample values of a same decoded slice as determined by block vectors;

wherein, when one block is split into the multiple sub-regions, intermediate prediction blocks are generated using information of each sub-region, and wherein a final prediction block is obtained based on a weighted average of the intermediate prediction blocks.

2. The method of claim 1 , wherein the block is split into four triangular sub-regions by applying both a diagonal split and an anti-diagonal split to the block.

3. The method of claim 1 , wherein the block is split into two wedgelet sub-regions with predetermined shapes.

4. The method of claim 1 , wherein, when the block is split into the multiple sub-regions, all of the multiple sub-regions are coded with the IBC mode, and wherein at least two of the multiple sub-regions are coded with different motion vectors (MVs).

5. The method of claim 1 , wherein, when the block is split into the multiple sub-regions, at least one of the multiple sub-regions is coded with the IBC mode, and another one is coded with a non-IBC mode.

6. The method of claim 1 , wherein the method is applied to one or more components of the block.

7. The method of claim 6 , wherein, when the method is applied to one color component and not applied to an other color component, a corresponding block in the other color component is coded as a whole block without splitting.

8. The method of claim 1 , wherein the IBC mode is treated as an inter mode and combined intra-inter prediction (CIIP) weights are applied to combine intra prediction and IBC prediction.

9. The method of claim 1 , wherein, when the method is applied, motion information of one sub-region is stored as motion information of the block as a whole.

10. The method of claim 1 , wherein, when the method is applied, motion information of sub-regions is stored for each basic unit, and wherein a basic unit has a minimum coding unit (CU) size.

11. The method of claim 1 , wherein, when the method is applied, an IBC history-based motion vector prediction (HMVP) table cannot be updated.

12. The method of claim 1 , wherein one or more motion vectors for IBC-coded sub-regions are used to update an IBC history-based motion vector prediction (HMVP) table.

13. The method of claim 1 , wherein, when the method is applied, a non-IBC history-based motion vector prediction (HMVP) table cannot be updated.

14. The method of claim 1 , wherein, when the method is applied, one or more motion vectors for inter-coded sub-regions are used to update a non-IBC history-based motion vector prediction (HMVP) table.

15. The method of claim 1 , wherein in-loop filtering process for the block depends on usage of the method.

16. The method of claim 1 , wherein the conversion includes encoding the block of the video into the bitstream.

17. The method of claim 1 , wherein the conversion includes decoding the block from the bitstream.

18. 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:

make a determination, for a conversion between a block of a video and a bitstream of the block, that an intra block copy (IBC) mode is applied to multiple sub-regions of the block, wherein the block is split into two or multiple triangular or wedgelet sub-regions; and

perform the conversion based on the determination,

wherein, in the IBC mode, prediction samples are derived from blocks of sample values of a same decoded slice as determined by block vectors;

wherein, when one block is split into the multiple sub-regions, intermediate prediction blocks are generated using information of each sub-region, and wherein a final prediction block is obtained based on a weighted average of the intermediate prediction blocks.

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:

making a determination that an intra block copy (IBC) mode is applied to multiple sub-regions of a block of the video, wherein the block is split into two or multiple triangular or wedgelet sub-regions; and

generating the bitstream based on the determination,

wherein in the IBC mode, prediction samples are derived from blocks of sample values of a same decoded slice as determined by block vectors;

wherein, when one block is split into the multiple sub-regions, intermediate prediction blocks are generated using information of each sub-region, and wherein a final prediction block is obtained based on a weighted average of the intermediate prediction blocks.

20. The apparatus of claim 18 , wherein the conversion includes decoding the block from the bitstream.