Method and apparatus for improved sub-block partitioning intra sub-partitions coding mode
A method of video decoding performed by a video decoder includes receiving a coded video bitstream including a current picture. The method further includes determining a block size of a current block coded in the intra sub-partition (ISP) coding mode. The method further includes determining a direction and number of partitions of the current block based on the determined block size. The method further includes decoding the current block based on the determined direction and number of partitions of the current block.
1. A method of video decoding performed by a video decoder, comprising:
receiving a coded video bitstream including a current picture;
determining a block size of a rectangular current block coded in an intra sub-partition (ISP) coding mode;
determining a direction and number of partitions of the rectangular current block based on a width and a height of the rectangular current block indicated by the determined block size; and
decoding the rectangular current block based on the determined direction and number of partitions of the rectangular current block,
wherein the rectangular current block is partitioned into one of (i) K vertically split partitions and (ii) L horizontally split partitions, and
wherein at least one of K and L are greater than 4 such that a number of partitions of the rectangular current block coded in the ISP coding mode is greater than 4.
2. The method according to claim 1 , wherein when the width of the rectangular current block is larger than the height of the rectangular current block, K is greater than L.
3. The method according to claim 1 , wherein when the height of the rectangular current block is larger than the width of the rectangular current block, K is smaller than L.
4. The method of claim 3 , wherein when the block size of the rectangular current block is 4×N and N is greater than 8, K and L are dependent on N.
5. The method according to claim 2 , wherein when the block size of the rectangular current block is N×4 and N is greater than 8, K and L are dependent on N.
6. The method of claim 1 , wherein when the width of the rectangular current block is greater than a threshold, a number of vertical partitions is based on the width of the rectangular current block.
7. The method of claim 1 , wherein when the height of the rectangular current block is greater than a threshold, a number of horizontal partitions is based on the height of the rectangular current block.
8. The method of claim 1 , wherein a context model used to entropy encode the direction of the partitioning of the rectangular current block is selected based on the determined block size.
9. The method of claim 1 , wherein a context model used to entropy encode the direction of the partitioning of the rectangular current block is selected based on a partitioning direction of one or more neighboring blocks that are coded in the ISP coding mode.
10. A video decoder for video decoding, comprising:
processing circuitry configured to:
receive a coded video bitstream including a current picture,
determine a block size of a rectangular current block coded in an intra sub-partition (ISP) coding mode,
determine a direction and number of partitions of the rectangular current block based on a width and a height of the rectangular current block indicated by the determined block size, and
decode the rectangular current block based on the determined direction and number of partitions of the rectangular current block,
wherein the rectangular current block is partitioned into one of (i) K vertically split partitions and (ii) L horizontally split partitions, and
wherein at least one of K and L are greater than 4 such that a number of partitions of the rectangular current block coded in the ISP coding mode is greater than 4.
11. The video decoder according to claim 10 , wherein when a width of the rectangular current block is larger than the height of the rectangular current block, K is greater than L.
12. The video decoder according to claim 10 , wherein when the height of the rectangular current block is larger than the width of the rectangular current block, K is smaller than L.
13. The video decoder of claim 12 , wherein when the block size of the rectangular current block is 4×N and N is greater than 8, K and L are dependent on N.
14. The video decoder according to claim 11 , wherein when the block size of the rectangular current block is N×4 and N is greater than 8, K and L are dependent on N.
15. 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 a block size of a rectangular current block coded in an intra sub-partition (ISP) coding mode;
determining a direction and number of partitions of the rectangular current block based on a width and a height of the rectangular current block indicated by the determined block size; and
decoding the rectangular current block based on the determined direction and number of partitions of the rectangular current block,
wherein the rectangular current block is partitioned into one of (i) K vertically split partitions and (ii) L horizontally split partitions, and
wherein at least one of K and L are greater than 4 such that a number of partitions of the rectangular current block coded in the ISP coding mode is greater than 4.