Intra sub-partitions related intra coding
Systems, methods, and instrumentalities may be used for decoding and/or encoding a coding unit (CD), An intra-prediction mode for a CD may be determined. A split mode may be determined based on the intra-prediction mode, to generate a plurality of sub-partitions in the CU. A prediction for a first sub-partition of the plurality of sub-partitions in the CU may be based on a reference sample in a second sub-partition of the plurality of sub-partitions in the CU. The CU may be decoded and/or encoded, for example, based on the determined split mode.
1. An apparatus for video decoding, comprising one or more processors, wherein the one or more processors are configured to:
determine an intra-prediction mode for a coding block;
infer a split mode based on the intra-prediction mode to generate a plurality of sub-partitions in the coding block, wherein a prediction for a first sub-partition of the plurality of sub-partitions in the coding block is based on a reference sample in a second sub-partition of the plurality of sub-partitions in the coding block, and wherein the split mode is inferred to be a vertical split mode based on a condition that the intra-prediction mode indicates that the coding block is to be decoded based on a plurality of reference samples adjacent to a left boundary of the coding block; and
decode the coding block based on the inferred split mode.
2. The apparatus of claim 1 , wherein the one or more processors are further configured to:
determine an intra-prediction mode for a second coding block; and
based on a condition that the intra-prediction mode indicates that the second coding block is to be decoded based on a second plurality of reference samples is adjacent to a top boundary of the second coding block, infer a horizontal split mode for the second coding block.
3. The apparatus of claim 1 , wherein the one or more processors are further configured to:
determine an intra-prediction mode for a second coding block; and
based on a condition that the intra-prediction mode indicates that the second coding block is to be decoded based on a first plurality of reference samples adjacent to a top boundary of the second coding block and based on a second plurality of reference samples adjacent to a left boundary of the second coding block, the infer a split mode for the second coding block based on a determination of whether the first plurality of reference samples is more than the second plurality of reference samples.
4. The apparatus of claim 1 , wherein the one or more processors are configured to:
partition the coding block into the plurality of sub-partitions based on the inferred split mode; and
reconstruct the second sub-partition comprising the reference sample based on a plurality of samples in a reference coding block.
5. The apparatus of claim 1 , wherein an intra sub-partition (ISP) is enabled for the coding block.
6. An apparatus for video encoding, comprising one or more processors, wherein the one or more processors are configured to:
determine an intra-prediction mode for a coding block;
determine a split mode based on the intra-prediction mode to generate a plurality of sub-partitions in the coding block, wherein a prediction for a first sub-partition of the plurality of sub-partitions in the coding block is based on a reference sample in a second sub-partition of the plurality of sub-partitions in the coding block, and wherein a vertical split mode is determined based on a condition that the intra-prediction mode indicates that the coding block is to be decoded based on a plurality of reference samples adjacent to a left boundary of the coding block; and
encode the coding block based on the determined split mode.
7. The apparatus of claim 6 , wherein the one or more processors are configured to:
generate a residual based on the coding block; and
include the residual in a bitstream without including an indication of the determined split mode in the bitstream.
8. The apparatus of claim 6 , wherein the one or more processors are configured to:
partition the coding block into the plurality of sub-partitions based on the determined split mode; and
reconstruct the second sub-partition comprising the reference sample based on a plurality of samples in a reference coding block.
9. The apparatus of claim 6 , wherein an intra sub-partition (ISP) is enabled for the coding block.
10. A method for video decoding, comprising:
determining an intra-prediction mode for a coding block;
inferring a split mode based on the intra-prediction mode to generate a plurality of sub-partitions in the coding block, wherein a prediction for a first sub-partition of the plurality of sub-partitions in the coding block is based on a reference sample in a second sub-partition of the plurality of sub-partitions in the coding block, and wherein a vertical split mode is inferred based on a condition that the intra-prediction mode indicates that the coding block is to be decoded based on a plurality of reference samples adjacent to a left boundary of the coding block; and
decoding the coding block based on the inferred split mode.
11. The method of claim 10 further comprising:
determining an intra-prediction mode for a second coding block; and
based on a condition that the intra-prediction mode indicates that the second coding block is to be decoded based on a second plurality of reference samples adjacent to a top boundary of the second coding block, inferring a horizontal split mode for the second coding block.
12. The method of claim 10 , wherein the method further comprises:
determining an intra-prediction mode for a second coding block; and
determining, based on the intra-prediction mode, whether the second coding block is to be decoded based on a first plurality of reference samples adjacent to a left boundary of the second coding block, based on a second plurality of reference samples adjacent to a top boundary of the second coding block, or based on at least one of the first plurality of reference samples and at least one of the second plurality of reference samples; and
inferring a split mode for the second coding block based on the determination of whether the second coding block is to be decoded based on the first plurality of reference samples adjacent to the left boundary of the second coding block, based on the second plurality of reference samples adjacent to the top boundary of the second coding block, or based on at least one of the first plurality of reference samples and at least one of the second plurality of reference samples.
13. The method of claim 10 , wherein the method further comprises:
partitioning the coding block into the plurality of sub-partitions based on the inferred split mode; and
reconstructing the second sub-partition comprising the reference sample based on a plurality of samples in a reference coding block.
14. A method for video encoding, comprising:
determining an intra-prediction mode for a coding block;
determining a split mode based on the intra-prediction mode to generate a plurality of sub-partitions in the coding block, wherein a prediction for a first sub-partition of the plurality of sub-partitions in the coding block is based on a reference sample in a second sub-partition of the plurality of sub-partitions in the coding block, and wherein a vertical split mode is determined based on a condition that the intra-prediction mode indicates that the coding block is to be decoded based on a plurality of reference samples adjacent to a left boundary of the coding block; and
encoding the coding block based on the determined split mode.
15. The method of claim 14 , wherein the method further comprises bypassing sending an indication of the determined split mode.
16. The method of claim 14 , wherein the method further comprises:
partitioning the coding block into the plurality of sub-partitions based on the determined split mode; and
reconstructing the second sub-partition comprising the reference sample based on a plurality of samples in a reference coding block.
17. The method of claim 14 , wherein an intra sub-partition (ISP) is enabled for the coding block.
18. A non-transitory, computer readable medium comprising computer-executable instructions for causing one or more processors to perform the method of claim 10 .