Video coding using intra sub-partition coding mode
A method of video coding comprises independently generating a respective intra prediction for each of a plurality of corresponding sub-partitions. Each respective intra prediction is generated using a plurality of reference samples from a current coding block. Illustratively, no reconstructed sample from a first sub-partition of the plurality of corresponding sub-partitions is used to generate a respective intra prediction for any other sub-partition of the plurality of corresponding sub-partitions, and each of the plurality of corresponding sub-partitions has a width less than or equal to 2.
1. A method of video encoding, comprising:
performing an intra prediction for a plurality of sub-partitions of a coding block in a Intra Sub-Partition (ISP) mode in response to determining that the plurality of sub-partitions meet first conditions for the intra prediction, wherein the coding block has a square shape or a rectangular shape,
wherein performing the intra prediction for the plurality of sub-partitions of the coding block comprises:
merging at least two sub-partitions of the plurality of sub-partitions into one prediction region for the intra prediction, and
generating predicted samples for the one prediction region in the intra prediction based on a plurality of reference samples of the coding block adjacent to the one prediction region,
wherein the first conditions comprise that the plurality of sub-partitions are a plurality of vertical sub-partitions and each of the sub-partitions has a width less than or equal to 2.
2. The method of claim 1 , wherein no reconstructed sample from one sub-partition of the at least two sub-partitions is used to perform the intra prediction for any other sub-partition of the at least two sub-partitions.
3. The method of claim 1 , further comprising:
generating a set of predicted samples for the plurality of vertical sub-partitions using a vertical prediction mode with a mode index larger than 50.
4. The method of claim 1 , further comprising performing the intra prediction for samples in the one prediction region independently and in parallel.
5. The method of claim 1 , wherein the plurality of sub-partitions includes a last sub-partition, and the method further comprises signaling a coefficients block flag (CBF) value for the last sub-partition.
6. The method of claim 5 , wherein the plurality of sub-partitions includes a last sub-partition, and the method further comprises inferring a coefficients block flag (CBF) value for the last sub-partition at an encoder.
7. The method of claim 6 , wherein the coefficients block flag (CBF) value is inferred as one or zero.
8. The method of claim 1 , wherein multiple prediction samples for the intra prediction are generated in parallel for the plurality of sub-partitions.
9. An apparatus of video encoding, comprising:
one or more processors;
a non-transitory computer-readable memory storing instructions executable by the one or more processors,
wherein the one or more processors are configured to:
perform an intra prediction for a plurality of sub-partitions of a coding block in a Intra Sub-Partition (ISP) mode in response to determining that the plurality of sub-partitions meet first conditions for the intra prediction, wherein the coding block has a square shape or a rectangular shape,
wherein performing the intra prediction for the plurality of sub-partitions of the coding block comprises:
merging at least two sub-partitions of the plurality of sub-partitions into one prediction region for the intra prediction, and
generating predicted samples for the one prediction region in the intra prediction based on a plurality of reference samples of the coding block adjacent to the one prediction region,
wherein the first conditions comprise that the plurality of sub-partitions are a plurality of vertical sub-partitions and each of the sub-partitions has a width less than or equal to 2.
10. The apparatus of claim 9 , wherein no reconstructed sample from one sub-partition of the at least two sub-partitions is used to perform the intra prediction for any other sub-partition of the at least two sub-partitions.
11. The apparatus of claim 9 , wherein, the one or more processors are further configured to:
generate a set of predicted samples for the plurality of vertical sub-partitions using a vertical prediction mode with a mode index larger than 50.
12. The apparatus of claim 9 , wherein, the one or more processors are further configured to: perform the intra prediction for the plurality of vertical sub-partitions independently and in parallel.
13. The apparatus of claim 9 , wherein the plurality of sub-partitions includes a last sub-partition, and the method further comprises signaling a coefficients block flag (CBF) value for the last sub-partition.
14. The apparatus of claim 13 , wherein the plurality of sub-partitions includes a last sub-partition, and the method further comprises inferring a coefficients block flag (CBF) value for the last sub-partition at an encoder.
15. The apparatus of claim 14 , wherein the coefficients block flag (CBF) value is inferred as one or zero.
16. A non-transitory computer readable storage medium storing a bitstream generated by the encoding method comprising:
performing an intra prediction for a plurality of sub-partitions of a coding block in a Intra Sub-Partition (ISP) mode in response to determining that the plurality of sub-partitions meet first conditions for the intra prediction, wherein the coding block has a square shape or a rectangular shape,
wherein performing the intra prediction for the plurality of sub-partitions of the coding block comprises:
merging at least two sub-partitions of the plurality of sub-partitions into one prediction region for the intra prediction, and
generating predicted samples for the one prediction region in the intra prediction based on a plurality of reference samples of the coding block adjacent to the one prediction region,
wherein the first conditions comprise that the plurality of sub-partitions are a plurality of vertical sub-partitions and each of the sub-partitions has a width less than or equal to 2.
17. The non-transitory computer readable storage medium of claim 16 , wherein no reconstructed sample from one sub-partition of the at least two sub-partitions is used to perform the intra prediction for any other sub-partition of the at least two sub-partitions.
18. The non-transitory computer readable storage medium of claim 16 , wherein the encoding operations further comprises:
generating a set of predicted samples for the plurality of vertical sub-partitions using a vertical prediction mode with a mode index larger than 50.
19. The non-transitory computer readable storage medium of claim 16 , wherein the encoding operations further comprises:
performing the intra prediction for the plurality of vertical sub-partitions independently and in parallel.
20. The non-transitory computer readable storage medium of claim 16 , wherein the encoding operations further comprises: signaling a coefficients block flag (CBF) value for a last sub-partition in the plurality of sub-partitions.