Method and apparatus for signaling predictor candidate list size
A method of video decoding includes receiving a coded video bitstream including a current picture. The method further includes determining whether a current block included in the current picture is coded in intra block copy (IBC) mode. The method further includes, in response to the current block being coded in the IBC mode, determining a number of IBC predictor candidates associated with the current block. The method further includes constructing an IBC predictor candidate list having a size corresponding to the number of IBC predictor candidates. The method further includes selecting a block vector predictor from the IBC predictor candidate list. The method further includes decoding a block vector associated with the current block using the block vector predictor. The method further includes decoding the current block in accordance with the block vector.
1. A method of video decoding, comprising:
receiving a coded video bitstream including a current picture;
determining whether a current block included in the current picture is coded in an intra block copy (IBC) mode;
in response to determining that the current block is coded in the IBC mode, determining a number of IBC predictor candidates associated with the current block by (1) calculating a value max(M, min(MaxNumMergeCand, N)), wherein MaxNumMergeCand is equal to a number of candidates in a merge mode list, M is a predetermined integer, and N is a predetermined integer greater than M, and (2) setting the number of IBC predictor candidates to the calculated value;
constructing an IBC predictor candidate list having a size corresponding to the determined number of IBC predictor candidates;
selecting a block vector predictor from the IBC predictor candidate list, wherein when the size of the IBC predictor candidate list is equal to 1, a motion vector predictor index for the IBC mode is not signaled;
decoding a block vector associated with the current block using the block vector predictor; and
decoding the current block in accordance with the block vector.
2. The method according to claim 1 , wherein, in the step of determining the number of IBC predictor candidates, M is 2.
3. The method according to claim 2 , wherein, in the step of determining the number of IBC predictor candidates, N is 5.
4. A video decoder for performing video decoding, comprising:
processing circuitry configured to:
receive a coded video bitstream including a current picture,
determine whether a current block included in the current picture is coded in intra block copy (IBC) mode,
in response to determining that the current block is coded in the IBC mode, determine a number of IBC predictor candidates associated with the current block by (1) calculating a value max(M, min(MaxNumMergeCand, N)), wherein MaxNumMergeCand is equal to a number of candidates in a merge mode list, M is a predetermined integer, and N is a predetermined integer greater than M, and (2) setting the number of IBC predictor candidates to the calculated value,
construct an IBC predictor candidate list having a size corresponding to the determined number of IBC predictor candidates, wherein when the size of the IBC predictor candidate list is equal to 1, a motion vector predictor index for the IBC mode is not signaled,
select a block vector predictor from the IBC predictor candidate list,
decode a block vector associated with the current block using the block vector predictor, and
decode the current block in accordance with the block vector.
5. The video decoder according to claim 4 , wherein, in determining the number of IBC predictor candidates, M is 2.
6. The video decoder according to claim 5 , wherein, in determining the number of IBC predictor candidates, N is 5.
7. 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:
receiving a coded video bitstream including a current picture;
determining whether a current block included in the current picture is coded in intra block copy (IBC) mode;
in response to determining that the current block is coded in the IBC mode, determining a number of IBC predictor candidates associated with the current block by (1) calculating a value max(M, min(MaxNumMergeCand, N)), wherein MaxNumMergeCand is equal to a number of candidates in a merge mode list, M is a predetermined integer, and N is a predetermined integer greater than M, and (2) setting the number of IBC predictor candidates to the calculated value;
constructing an IBC predictor candidate list having a size corresponding to the determined number of IBC predictor candidates, wherein when the size of the IBC predictor candidate list is equal to 1, a motion vector predictor index for the IBC mode is not signaled;
selecting a block vector predictor from the IBC predictor candidate list;
decoding a block vector associated with the current block using the block vector predictor; and
decoding the current block in accordance with the block vector.
8. The non-transitory computer readable medium according to claim 7 , wherein, in the step of determining the number of IBC predictor candidates, M is 2.
9. The non-transitory computer readable medium according to claim 8 , wherein, in determining the number of IBC predictor candidates, N is 5.