Method and apparatus for block vector signaling and derivation in intra picture block compensation

1. A method of video decoding for a video decoder, comprising:

acquiring a current picture from a coded video bitstream;

determining whether a current block in the current picture is coded in an intra block copy mode;

in response to the determination that the current block is coded in the intra block copy mode, determining whether a current block vector of the current block is one of (i) a signaled block vector and (ii) a derived block vector; and

in response to determining that the current block vector is the derived block vector:

(i) selecting a region in the reference picture, the region divided into a plurality of locations,

(ii) determining a difference between a template and each of the plurality of locations in the region,

(iii) deriving the current block vector based on a displacement vector between the current block and a location in the region having a minimum difference with the template with respect to each other location in the region,

(iv) selecting a reference block in the current picture based on the derived current block vector, and

(v) decoding the current block based on at least one characteristic of the reference block.

2. The method of claim 1 , wherein determining whether the current block vector is one of the signaled block vector and the derived block vector further includes selecting a candidate block from a merge candidate list that indicates that the current block is the derived block vector.

3. The method of claim 2 , wherein the selected candidate block that indicates that the current block is the derived block vector is inserted after each neighboring block included in the merge candidate list.

4. The method of claim 2 , wherein the selected candidate block that indicates that the current block is the derived block vector is inserted at a beginning of the merge candidate list.

5. The method of claim 2 , wherein the selecting the region is based on an index included in the merge candidate list.

6. The method of claim 2 , wherein the selected candidate that indicates that the current block vector is derived includes a block vector predictor of a neighboring block of the current block included in the candidate list, and wherein the selecting the region in the reference picture is based on the block vector predictor.

7. The method of claim 2 , wherein the selected candidate that indicates that the current block vector is the derived clock vector includes a block vector predictor of a temporal block of the current block included in the candidate list, and wherein the selecting the region in the reference picture is based on the block vector predictor.

8. The method of claim 1 , wherein the current block vector is determined as being one of the signaled block vector and the derived block vector based on a flag included in the coded video bitstream.

9. The method of claim 1 , the method further comprising:

in response to determining that the current block vector is the signaled block vector, creating a predictor list that includes a block vector predictor of each neighboring block of the current block in a merge candidate list that is encoded in the intra block copy mode;

selecting a block vector predictor from the block vector predictor list;

selecting a reference block in the current picture based on the selected block vector predictor; and

decoding the current block based on at least one characteristic of the reference block.

10. The method of claim 9 , wherein the predictor list further includes a block vector predictor of each temporal block in the merge candidate list that is encoded in the intra block copy mode.

11. A video decoder for video decoding, comprising:

processing circuitry configured to:

acquire a current picture from a coded video bitstream,

determine whether a current block in the current picture is coded in an intra block copy mode,

in response to the determination that the current block is coded in the intra block copy mode, determine whether a current block vector of the current block is one of (i) a signaled block vector and (ii) a derived block vector, and

in response to the determination that the current block vector is the derived block vector:

(i) select a region in the reference picture, the region divided into a plurality of locations,

(ii) determine a difference between a template and each of the plurality of locations in the region,

(iii) derive the current block vector based on a displacement vector between the current block and a location in the region having a minimum difference with the template with respect to each other location in the region,

(iv) select a reference block in the current picture based on the derived current block vector, and

(v) decode the current block based on at least one characteristic of the reference block.

12. The video decoder of claim 11 , wherein the determination whether the current block vector is one of the signaled block vector and the derived block vector further includes the processing circuitry configured to select a candidate block from a merge candidate list that indicates that the current block is the derived block vector.

13. The video decoder of claim 12 , wherein the selected candidate block that indicates that the current block is the derived block vector is inserted after each neighboring block included in the merge candidate list.

14. The video decoder of claim 12 , wherein the selected candidate block that indicates that the current block is the derived block vector is inserted at a beginning of the merge candidate list.

15. The video decoder of claim 12 , wherein the selection of the region is based on an index included in the merge candidate list.

16. The video decoder of claim 12 , wherein the selected candidate that indicates that the current block vector is derived includes a block vector predictor of a neighboring block of the current block included in the candidate list, and wherein the selection of the region in the reference picture is based on the block vector predictor.

17. The video decoder of claim 12 , wherein the selected candidate that indicates that the current block vector is the derived clock vector includes a block vector predictor of a temporal block of the current block included in the candidate list, and wherein the selection of the region in the reference picture is based on the block vector predictor.

18. The video decoder of claim 11 , wherein the current block vector is determined as being one of the signaled block vector and the derived block vector based on a flag included in the coded video bitstream.

19. The video decoder of claim 11 , wherein the processing circuitry is further configured to:

in response to the determination that the current block vector is the signaled block vector, create a predictor list that includes a block vector predictor of each neighboring block of the current block in a merge candidate list that is encoded in the intra block copy mode,

select a block vector predictor from the block vector predictor list,

select a reference block in the current picture based on the selected block vector predictor, and

decode the current block based on at least one characteristic of the reference block.

20. A non-transitory computer readable medium having instructions stored therein, which when executed by a processor in a video decoder causes the processor to execute a method comprising:

acquiring a current picture from a coded video bitstream;

determining whether a current block in the current picture is coded in an intra block copy mode;

in response to the determination that the current block is coded in the intra block copy mode, determining whether a current block vector of the current block is one of (i) a signaled block vector and (ii) a derived block vector; and

in response to determining that the current block vector is the derived block vector:

(i) selecting a region in the reference picture, the region divided into a plurality of locations,

(ii) determining a difference between a template and each of the plurality of locations in the region,

(iii) deriving the current block vector based on a displacement vector between the current block and a location in the region having a minimum difference with the template with respect to each other location in the region,

(iv) selecting a reference block in the current picture based on the derived current block vector, and

(v) decoding the current block based on at least one characteristic of the reference block.