Template-matching based adaptive block vector resolution (ABVR) in IBC

1 . A method of video decoding performed in a video decoder, the method comprising:

receiving a video bitstream including coding information of a current block, the coding information indicating that an intra block copy (IBC) mode is applied to the current block; and

based on the IBC mode being applied to the current block, obtaining first adaptive block vector resolution (ABVR) information included in the coding information from the received video bitstream;

determining that the first ABVR information indicates that a plurality of BV precisions is associated with a block vector (BV) of the IBC mode;

reordering the plurality of BV precisions associated with the BV of the current block based on template matching (TM) differences between a template region of the current block and each of a plurality of template regions of reference blocks;

selecting a particular BV precision from the plurality of reordered BV precisions by the TM differences; and

reconstructing the current block based at least on the selected particular BV precision.

2 . The method of claim 1 , wherein the reordering further comprises:

determining the TM differences between the template region of the current block and each of the template regions of the reference blocks of the current block associated with the plurality of BV precisions, the template region of the current block including samples over a top side and on a left side of the current block; and

reordering the plurality of BV precisions based on the TM differences between the template region of the current block and the template regions of the reference blocks of the current block in an ascending order.

3 . The method of claim 1 , wherein:

the first ABVR information includes first precision index information that indicates the particular BV precision corresponding to a minimum TM difference among the TM differences between the template region of the current block and the template regions of the reference blocks of the current block, and

the selecting includes selecting the particular BV precision from the plurality of reordered BV precisions that corresponds to the minimum TM difference according to the first precision index information.

4 . The method of claim 1 , wherein the selecting further comprises:

based on the IBC mode being applied to the current block and the first ABVR information indicating that the particular BV precision corresponds to a minimum TM difference among the TM differences, selecting the particular BV precision from the plurality of reordered BV precisions corresponding to the minimum TM difference among the TM differences between the template region of the current block and the template regions of the reference blocks of the current block.

5 . The method of claim 4 , wherein the selecting further comprises:

based on the IBC mode being applied to the current block and the first ABVR information indicating that the particular BV precision does not correspond to the minimum TM difference,

selecting the particular BV precision from the plurality of reordered BV precisions based on first precision index information included in the coding information that indicates the particular BV precision corresponding to a second minimum difference among the TM differences between the template region of the current block and the template regions of the reference blocks of the current block.

6 . The method of claim 1 , wherein the reordering further comprises:

based on the first ABVR information indicating that a predetermined BV precision is excluded from the plurality of BV precisions,

reordering a subset of the plurality of BV precisions that excludes the predetermined BV precision based on TM differences between the template region of the current block and template regions of a subset of the reference blocks of the current block that excludes a predetermined reference block corresponding to the predetermined BV precision in an ascending order.

7 . The method of claim 6 , wherein the selecting further comprises:

selecting the particular BV precision from the plurality of reordered BV precisions based on first precision index information included in the coding information that indicates the particular BV precision corresponding to a minimum TM difference among the TM differences between the template region of the current block and the template regions of the subset of the reference blocks of the current block.

8 . The method of claim 1 , wherein the selecting further comprises:

based on the first ABVR information indicating that the one of the plurality of BV precisions does not correspond to a minimum TM difference among the TM differences, determining whether second ABVR information of the coding information indicates that the plurality of BV precisions is ordered based on a pre-defined sequence; and

based on the second ABVR information indicating that the plurality of BV precisions is ordered according to the pre-defined sequence, selecting the particular BV precision from the plurality of BV precisions in the pre-defined sequence based on second precision index information that is included in the coding information and indicates which one of the plurality of BV precisions is selected.

9 . The method of claim 1 , wherein the selecting further comprises:

based on the first ABVR information indicating that ABVR is enabled such that the plurality of BV precisions is ordered according to a pre-defined sequence, determining whether second ABVR information of the coding information indicates that the plurality of BV precisions is reordered based on the TM differences; and

based on the second ABVR information being determined as indicating that the plurality of BV precisions is reordered based on the TM differences, selecting the particular BV precision from the plurality of reordered BV precisions that corresponds to a minimum difference among the TM differences between the template region of the current block and the template regions of the reference blocks of the current block.

10 . The method of claim 9 , wherein the selecting further comprises:

based on the first ABVR information indicating that the ABVR is enabled, determining whether the second ABVR information of the coding information indicates that the plurality of BV precisions is reordered based on the TM differences; and

based on the second ABVR information being determined as indicating that the plurality of BV precisions is not reordered based on the TM differences, selecting the particular BV precision from the plurality of BV precisions in a pre-defined sequence based on second precision index information that indicates which one of the plurality of BV precisions is selected.

11 . An apparatus, the apparatus comprising:

processing circuitry configured to:

receive a video bitstream including coding information of a current block, the coding information indicating that an intra block copy (IBC) mode is applied to the current block; and

based on the IBC mode being applied to the current block, obtain first adaptive block vector resolution (ABVR) information included in the coding information from the received video bitstream;

determine that the first ABVR information indicates that a plurality of BV precisions is associated with a block vector (BV) of the IBC mode;

reorder the plurality of BV precisions associated with the BV of the current block based on template matching (TM) differences between a template region of the current block and each of a plurality of template regions of reference blocks;

select a particular BV precision from the plurality of reordered BV precisions by the TM differences; and

reconstruct the current block based at least on the selected particular BV precision.

12 . The apparatus of claim 11 , wherein the processing circuitry is configured to:

determine the TM differences between the template region of the current block and each of the template regions of the reference blocks of the current block associated with the plurality of BV precisions, the template region of the current block including samples over a top side and on a left side of the current block; and

reorder the plurality of BV precisions based on the TM differences between the template region of the current block and the template regions of the reference blocks of the current block in an ascending order.

13 . The apparatus of claim 11 , wherein:

the first ABVR information includes first precision index information that indicates the particular BV precision corresponding to a minimum TM difference among the TM differences between the template region of the current block and the template regions of the reference blocks of the current block, and

the processing circuitry is configured to:

select the particular BV precision from the plurality of reordered BV precisions that corresponds to the minimum TM difference according to the first precision index information.

14 . The apparatus of claim 11 , wherein the processing circuitry is configured to:

based on the IBC mode being applied to the current block and the first ABVR information indicating that the particular BV precision corresponds to a minimum TM difference among the TM differences, select the particular BV precision from the plurality of reordered BV precisions corresponding to the minimum TM difference among the TM differences between the template region of the current block and the template regions of the reference blocks of the current block.

15 . The apparatus of claim 14 , wherein the processing circuitry is configured to:

based on the IBC mode being applied to the current block and the first ABVR information indicating that the particular BV precision does not correspond to the minimum TM difference,

select the particular BV precision from the plurality of reordered BV precisions based on first precision index information included in the coding information that indicates the particular BV precision corresponding to a second minimum difference among the TM differences between the template region of the current block and the template regions of the reference blocks of the current block.

16 . The apparatus of claim 11 , wherein the processing circuitry is configured to:

based on the first ABVR information indicating that a predetermined BV precision is excluded from the plurality of BV precisions,

reorder a subset of the plurality of BV precisions that excludes the predetermined BV precision based on TM differences between the template region of the current block and template regions of a subset of the reference blocks of the current block that excludes a predetermined reference block corresponding to the predetermined BV precision in an ascending order.

17 . The apparatus of claim 16 , wherein the processing circuitry is configured to:

select the particular BV precision from the plurality of reordered BV precisions based on first precision index information included in the coding information that indicates the particular BV precision corresponding to a minimum TM difference among the TM differences between the template region of the current block and the template regions of the subset of the reference blocks of the current block.

18 . The apparatus of claim 11 , wherein the processing circuitry is configured to:

based on the first ABVR information indicating that the one of the plurality of BV precisions does not correspond to a minimum TM difference among the TM differences, determine whether second ABVR information of the coding information indicates that the plurality of BV precisions is ordered based on a pre-defined sequence; and

based on the second ABVR information indicating that the plurality of BV precisions is ordered according to the pre-defined sequence, select the particular BV precision from the plurality of BV precisions in the pre-defined sequence based on second precision index information that is included in the coding information and indicates which one of the plurality of BV precisions is selected.

19 . The apparatus of claim 11 , wherein the processing circuitry is configured to:

based on the first ABVR information indicating that ABVR is enabled such that the plurality of BV precisions is ordered according to a pre-defined sequence, determine whether second ABVR information of the coding information indicates that the plurality of BV precisions is reordered based on the TM differences; and

based on the second ABVR information being determined as indicating that the plurality of BV precisions is reordered based on the TM differences, select the particular BV precision from the plurality of reordered BV precisions that corresponds to a minimum difference among the TM differences between the template region of the current block and the template regions of the reference blocks of the current block.

20 . The apparatus of claim 19 , wherein the processing circuitry is configured to:

based on the first ABVR information indicating that the ABVR is enabled, determine whether the second ABVR information of the coding information indicates that the plurality of BV precisions is reordered based on the TM differences; and

based on the second ABVR information being determined as indicating that the plurality of BV precisions is not reordered based on the TM differences, select the particular BV precision from the plurality of BV precisions in a pre-defined sequence based on second precision index information that indicates which one of the plurality of BV precisions is selected.