Intra sub partitions for video encoding and decoding combined with multiple transform selection, matrix weighted intra prediction or multi-reference-line intra prediction
In an encoding apparatus or a decoding apparatus, an encoding method or decoding method combines various coding tools with intra sub partitioning mode in which a coding unit is split in multiple sub partitions. At least one embodiment particularly aims at the selection of primary transforms among a set of multiple transforms for video encoding or decoding of intra sub block partitions. At least one embodiment particularly aims at intra coding using Matrix-Based Intra Prediction mode combined with Intra Sub Partition mode. At least one embodiment particularly aims at intra coding using Multi-Reference-Line intra prediction mode combined with Intra Sub Partition mode.
1. A method comprising:
obtaining information representative of a block of a video, wherein the block is coded using an intra-sub partition mode and the block is partitioned into sub partitions;
obtaining a syntax element representative of a reference line index, wherein the syntax element is signaled at the block level;
partitioning the block into sub partitions;
selecting a single reference line based on the reference line index;
for each of the sub partitions, predicting samples of the sub partitions based on applying a 2D matrix and 1D vector to a vector based on averaged samples of the single reference line;
applying an inverse transform to the sub partitions; and
decoding the block;
wherein the single reference line is selected from among multiple reference lines adjacent to a top line of the block or to a left column of the block and is used to predict all the sub partitions of the block.
2. A method comprising, for a block of a video coded using an intra-sub partition mode:
partitioning the block into sub partitions;
selecting a single reference line from among multiple reference lines adjacent to a top line of the block or to a left column of the block;
for each of the sub partitions, predicting samples of the sub partitions based on applying a 2D matrix and 1D vector to a vector based on averaged samples of the single reference line;
applying a transform to the sub partitions; and
encoding the block and signaling information, wherein the block is coded in intra-sub partition mode and the signaling information comprises a syntax element representative of a reference line index used for the predicting, wherein the syntax element is signaled at the block level;
wherein the single reference line is used to predict all the sub partitions of the block.
3. A video encoding apparatus comprising a processor configured to, for a block of a video coded using an intra-sub partition mode:
partition the block into sub partitions;
select a single reference line from among multiple reference lines adjacent to a top line of the block or to a left column of the block;
for each of the sub partitions, predict samples of the sub partitions based on applying a 2D matrix and 1D vector to a vector based on averaged samples of the single reference line;
apply a transform to the sub partitions; and
encode the block and signaling information, wherein the block is coded in intra-sub partition mode and the signaling information comprises a syntax element representative of a reference line index used for the predicting, wherein the syntax element is signaled at the block level;
wherein the single reference line is used to predict all the sub partitions of the block.
4. A video decoding apparatus comprising a processor configured to:
obtain information representative of a block of a video, wherein the block is coded using an intra-sub partition mode and the block is partitioned into sub partitions;
obtain a syntax element representative of a reference line index, wherein the syntax element is signaled at the block level;
partition the block into sub partitions;
select a single reference line based on the reference line index;
for each of the sub partitions, predict samples of the sub partitions based on applying a 2D matrix and 1D vector to a vector based on averaged samples of the single reference line;
apply an inverse transform to the sub partitions; and
decode the block;
wherein the single reference line is selected from among multiple reference lines adjacent to a top line of the block or to a left column of the block and is used to predict all the sub partitions of the block.
5. A non-transitory computer readable medium comprising program code instructions executable by a processor for implementing the method according to claim 1 .
6. A non-transitory computer readable medium comprising program code instructions executable by a processor for implementing the method according to claim 2 .
7. The method of claim 1 , wherein the type of partitioning is horizontal or vertical according to the value of the reference line index.
8. The method of claim 1 , wherein the type of partitioning is horizontal when the reference line index is equal to 1 and vertical when the reference line index is equal to 3.
9. The method of claim 1 , wherein the type of partitioning is horizontal when the reference line index is equal to 3 and vertical when the reference line index is equal to 1.
10. The method of claim 2 , wherein the type of partitioning is horizontal or vertical according to the value of the reference line index.
11. The method of claim 2 , wherein the type of partitioning is horizontal when the reference line index is equal to 1 and vertical when the reference line index is equal to 3.
12. The method of claim 2 , wherein the type of partitioning is horizontal when the reference line index is equal to 3 and vertical when the reference line index is equal to 1.
13. The apparatus of claim 3 , wherein the type of partitioning is horizontal or vertical according to the value of the reference line index.
14. The apparatus of claim 3 , wherein the type of partitioning is horizontal when the reference line index is equal to 1 and vertical when the reference line index is equal to 3.
15. The apparatus of claim 3 , wherein the type of partitioning is horizontal when the reference line index is equal to 3 and vertical when the reference line index is equal to 1.
16. The apparatus of claim 4 , wherein the type of partitioning is horizontal or vertical according to the value of the reference line index.
17. The apparatus of claim 4 , wherein the type of partitioning is horizontal when the reference line index is equal to 1 and vertical when the reference line index is equal to 3.
18. The apparatus of claim 4 , wherein the type of partitioning is horizontal when the reference line index is equal to 3 and vertical when the reference line index is equal to 1.