Method and apparatus for video coding

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

receiving coded information of a current block from a coded video bitstream;

determining dimension information and partition information of the current block based on the coded information, the dimension information indicating at least one of a height, a width, and a size of the current block, the coded information indicating a binary tree (BT) depth of a coding unit (CU) partition of the current block;

determining a partition mode of the current block as one of an intra sub-partition (ISP) mode and a coding unit partition based on the dimension information and the partition information of the current block, wherein the determining the partition mode of the current block comprises determining whether the partition mode is not the ISP mode based on (i) the height or the width of the current block compared to a first value and the BT depth, or (ii) the height or the width of the current block compared to a second value, the size of the current block compared to a third value, and the BT depth, wherein the first value is equal to 8 pixels for a 2×N ISP partition, and 4 pixels for a 1×N ISP partition, the second value is 8 pixels, and the third value is 32 luma samples; and

decoding the current block based on the determined partition mode of the current block.

2. The method of claim 1 , wherein the determining the partition mode of the current block further comprises:

determining that the partition mode is not the ISP mode along a vertical direction of the current block in response to (i) the width of the current block being larger than the first value and the BT depth plus two being equal to or less than a maximum allowed BT depth, or (ii) the width of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth.

3. The method of claim 1 , wherein the determining the partition mode of the current block further comprises:

determining that the partition mode is not the ISP mode along a horizontal direction of the current block in response to (i) the height of the current block being larger than the first value and the BT depth plus two being equal to or less than a maximum allowed BT depth, or (ii) the height of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth.

4. The method of claim 1 , wherein the determining the partition mode of the current block further comprises:

determining a first condition that includes one of (i) the width of the current block being larger than the first value and the BT depth plus two being equal to or less than a maximum allowed BT depth, and (ii) the width of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth;

determining a second condition that includes one of (i) the height of the current block being larger than the first value and the BT depth plus two being equal to or less than the maximum allowed BT depth, and (ii) the height of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth;

determining a corresponding context model from a set of context models in response to each of:

(i) both the first condition and the second condition being true,

(ii) one of the first condition and the second condition being true, and

(iii) none of the first condition and the second condition being true; and

determining the partition mode of the current block according to the corresponding context model.

5. The method of claim 1 , wherein the determining the partition mode of the current block further comprises:

determining a first condition that includes one of (i) the width of the current block being larger than the first value and the BT depth plus two being equal to or less than a maximum allowed BT depth; and (ii) the width of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than a maximum allowed BT depth;

determining a second condition that includes one of (i) the height of the current block being larger than the first value and the BT depth plus two being equal to or less than the maximum allowed BT depth, and (ii) the height of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth;

determining a corresponding context model from a set of context models in response to each of:

(i) both the first condition and the second condition being false, and

(ii) at least one of the first condition and the second condition being true; and

determining the partition mode of the current block according to the corresponding context model.

6. The method of claim 1 , wherein the determining the partition mode of the current block further comprises:

determining that the partition mode is not the ISP mode along one of a horizontal direction and a vertical direction of the current block based on a ratio of the height and the width of the current block.

7. The method of claim 1 , wherein the decoding the current block comprises:

partitioning the current block into square sub-blocks in the ISP mode.

8. A method for video decoding in an encoder, comprising:

determining dimension information and partition information of a current block in a current picture of a video, the dimension information indicating at least one of a height, a width, and a size of the current block, and the partition information indicating a binary tree (BT) depth of a coding unit partition of the current block; and

generating signaling information for the current block based on the dimension information and the partition information, wherein

the signaling information indicates that a partition mode of the current block is not a intra sub-partition (ISP) mode along a vertical direction of the current block based on one of (i) the width of the current block being larger than a first value and the BT depth plus two being equal to or less than a maximum allowed BT depth, and (ii) the width of the current block being larger than a second value, the size of the current block being equal to a third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth; and

the signaling information indicates that the partition mode of the current block is not the ISP mode along a horizontal direction of the current block based on one of (i) the height of the current block being larger than the first value and the BT depth plus two being equal to or less than the maximum allowed BT depth, and (ii) the height of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth.

9. The method of claim 8 , wherein the first value is 8 pixels, the second value is 8 pixels, and the third value is 32 luma samples.

10. A decoder apparatus for video decoding, comprising:

processing circuitry configured to:

receive coded information of a current block from a coded video bitstream;

determine dimension information and partition information of the current block based on the coded information, the dimension information indicating at least one of a height, a width, and a size of the current block, the coded information indicating a binary tree (BT) depth of a coding unit (CU) partition of the current block;

determine a partition mode of the current block as one of an intra sub-partition (ISP) mode and a coding unit partition based on the dimension information and the partition information of the current block, wherein the determination of the partition mode of the current block determines whether the partition mode is not the ISP mode based on (i) the height or the width of the current block compared to a first value and the BT depth, or (ii) the height or the width of the current block compared to a second value, the size of the current block compared to a third value, and the BT depth, wherein the first value is equal to 8 pixels for a 2×N ISP partition, and 4 pixels for a 1×N ISP partition, the second value is 8 pixels, and the third value is 32 luma samples; and

decode the current block based on the determined partition mode of the current block.

11. The decoder apparatus of claim 10 , wherein the processing circuitry is further configured to:

determine that the partition mode is not the ISP mode along a vertical direction of the current block in response to (i) the width of the current block being larger than the first value and the BT depth plus two being equal to or less than a maximum allowed BT depth, or (ii) the width of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth.

12. The decoder apparatus of claim 10 , wherein the processing circuitry is further configured to:

determine that the partition mode is not the ISP mode along a horizontal direction of the current block in response to (i) the height of the current block being larger than the first value and the BT depth plus two being equal to or less than a maximum allowed BT depth, or (ii) the height of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth.

13. The decoder apparatus of claim 10 , wherein the processing circuitry is further configured to:

determine a first condition that includes one of (i) the width of the current block being larger than the first value and the BT depth plus two being equal to or less than a maximum allowed BT depth, and (ii) the width of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth;

determine a second condition that includes one of (i) the height of the current block being larger than the first value and the BT depth plus two being equal to or less than the maximum allowed BT depth, and (ii) the height of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth;

determine a corresponding context model from a set of context models in response to each of:

(i) both the first condition and the second condition being true,

(ii) one of the first condition and the second condition being true, and

(iii) none of the first condition and the second condition being true; and

determine the partition mode of the current block according to the corresponding context model.

14. The decoder apparatus of claim 10 , wherein the processing circuitry is further configured to:

determine a first condition that includes one of (i) the width of the current block being larger than the first value and the BT depth plus two being equal to or less than a maximum allowed BT depth; and (ii) the width of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than a maximum allowed BT depth;

determine a second condition that includes one of (i) the height of the current block being larger than the first value and the BT depth plus two being equal to or less than the maximum allowed BT depth, and (ii) the height of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth;

determine a corresponding context model from a set of context models in response to each of:

(i) both the first condition and the second condition being false, and

(ii) at least one of the first condition and the second condition being true; and

determine the partition mode of the current block according to the corresponding context model.

15. The decoder apparatus of claim 10 , wherein the processing circuitry is further configured to:

determine that the partition mode is not the ISP mode along one of a horizontal direction and a vertical direction of the current block based on a ratio of the height and the width of the current block.

16. The decoder apparatus of claim 10 , wherein the processing circuitry is further configured to:

partition the current block into square sub-blocks in the ISP mode.

17. An encoder apparatus, comprising:

processing circuitry configured to:

determine dimension information and partition information of a current block in a current picture of a video, the dimension information indicating at least one of a height, a width, and a size of the current block, and the partition information indicating a binary tree (BT) depth of a coding unit partition of the current block; and

generate signaling information for the current block based on the dimension information and the partition information, wherein

the signaling information indicates that a partition mode of the current block is not a intra sub-partition (ISP) mode along a vertical direction of the current block based on one of (i) the width of the current block being larger than a first value and the BT depth plus two being equal to or less than a maximum allowed BT depth, and (ii) the width of the current block being larger than a second value, the size of the current block being equal to a third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth; and

the signaling information indicates that the partition mode of the current block is not the ISP mode along a horizontal direction of the current block based on one of (i) the height of the current block being larger than the first value and the BT depth plus two being equal to or less than the maximum allowed BT depth, and (ii) the height of the current block being larger than the second value, the size of the current block being equal to the third value, and the BT depth plus one being equal to or less than the maximum allowed BT depth.

18. The encoder apparatus of claim 17 , wherein the first value is 8 pixels, the second value is 8 pixels, and the third value is 32 luma samples.