Interactions between sub-block based intra block copy and different coding tools

1. A method of processing video data, comprising:

determining, for a conversion between a current block of a video and a bitstream of the video, that the current block is split into multiple sub-blocks, wherein each of the multiple sub-blocks is coded in the bitstream using a corresponding coding technique according to a pattern; and

performing the conversion based on the determining;

wherein the pattern specifies that a first sub-block of the multiple sub-blocks is coded using a sub-block-based intra-block copy (sbIBC) coding technique in which reference samples from a video region are used.

2. The method of claim 1 , wherein the pattern specifies that a second sub-block of the multiple sub-blocks is coded by using one selected from the group consisting of:

an intra prediction coding technique in which samples from the same sub-block are used;

a palette coding technique in which a palette of representative pixel values is used; and

an inter coding technique in which temporal information is used.

3. The method of claim 1 , wherein the pattern specifies that a first sub-block of the multiple sub-blocks is coded using an intra prediction coding technique in which samples from the same sub-block are used.

4. The method of claim 3 , wherein the pattern specifies that a second sub-block of the multiple sub-blocks is coded using a palette coding technique in which a palette of representative pixel values is used or using an inter coding technique in which temporal information is used.

5. The method of claim 1 , wherein a history-based table of motion candidates for a sub-block temporal motion vector prediction mode remains same for the conversion in case the pattern of one or more coding techniques applies to the current block, the history-based table of motion candidates determined based on motion information in past conversions.

6. The method of claim 1 , wherein, in case the pattern specifies that at least one sub-block of the multiple sub-blocks is coded using the IBC coding technique, one or more motion vectors for the at least one sub-block are used to update a history-based table of motion candidates for an IBC sub-block temporal motion vector prediction mode, the history-based table of motion candidates determined based on motion information in past conversions.

7. The method of claim 1 , wherein, in case the pattern specifies that at least one sub-block of the multiple sub-blocks is coded using the inter coding technique, one or more motion vectors for the at least one sub-block are used to update a history-based table of motion candidates for a non-IBC sub-block temporal motion vector prediction mode, the history-based table of motion candidates determined based on motion information in past conversions.

8. The method of claim 1 , wherein usage of a filtering process in which boundaries of the multiple sub-blocks are filtered is based on usage of the at least one coding technique according to the pattern.

9. The method of claim 8 , wherein the filtering process filtering boundaries of the multiple sub-blocks is applied in case the at least one coding technique is applied.

10. The method of claim 1 , wherein a second coding technique is disabled for the current block for the conversion according to the pattern.

11. The method of claim 1 , wherein usage of the at least one coding technique according to the pattern is signaled in the bitstream.

12. The method of claim 11 , wherein the at least one coding technique comprises the modified IBC coding technique, and the modified IBC coding technique is indicated in the bitstream based on an index value indicating a candidate in a motion candidate list.

13. The method of claim 1 , wherein motion information of the multiple sub-blocks of the current block is used as a motion vector predictor for a conversion between a subsequent block of the video and the bitstream.

14. The method of claim 1 , wherein motion information of the multiple sub-blocks of the current block is disallowed to be used for a conversion between a subsequent block of the video and the bitstream.

15. The method of claim 1 , wherein the determining that the current block is split into the multiple sub-blocks coded using the at least one coding technique is based on whether a motion candidate is a candidate is applicable for a block of video or a sub-block within the block.

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

17. The method of claim 1 , wherein the conversion includes decoding the current video 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:

determine, for a conversion between a current block of a video and a bitstream of the video, that the current block is split into multiple sub-blocks, wherein each of the multiple sub-blocks is coded in the bitstream using a corresponding coding technique according to a pattern; and

perform the conversion based on the determining;

wherein the pattern specifies that a first sub-block of the multiple sub-blocks is coded using a sub-block-based intra-block copy (sbIBC) coding technique in which reference samples from a video region are used.

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 that the current block is split into multiple sub-blocks, wherein each of the multiple sub-blocks is coded in the bitstream using a corresponding coding technique according to a pattern; and

generating the bitstream based on the determining;

wherein the pattern specifies that a first sub-block of the multiple sub-blocks is coded using a sub-block-based intra-block copy (sbIBC) coding technique in which reference samples from a video region are used.