Method for encoding/decoding image signal and device for same
View Patent ↗An image decoding method according to the present invention includes: a step for determining a reference sample line of a current block; a step for determining whether candidate intra-prediction modes identical to the intra-prediction mode of the current block exist; a step for deriving the intra-prediction mode of the current block on the basis of the determination; and a step for performing intra-prediction on the current block on the basis of the reference sample line and the intra-prediction mode. Here, at least one of the candidate intra prediction modes may be derived by adding or subtracting an offset to or from the maximum value among the intra-prediction mode of a neighboring block that is above the current block and the intra-prediction mode of a neighboring block that is to the left of the current block.
1. A video decoding method comprising:
determining whether a candidate intra prediction mode is a same intra prediction mode as an intra prediction mode of a current block;
deriving the intra prediction mode of the current block based on the determination; and
performing intra prediction on the current block based on a reference sample line of the current block and the derived intra prediction mode, wherein
when a difference between the intra prediction mode of a top neighboring block and the intra prediction mode of a left neighboring block is 64, at least one among the candidate intra prediction modes is derived by adding or subtracting 2 to or from a maximum value.
2. The method according to claim 1 , further comprising the step of determining whether or not to partition the current block into a plurality of subblocks, wherein
when the current block is partitioned into a plurality of subblocks, the plurality of subblocks shares one intra prediction mode, and
a horizontal direction transform type and a vertical direction transform type of a subblock are determined based on a shape of the subblock.
3. The method according to claim 2 , wherein inverse transform is omitted for some of the plurality of subblocks.
4. The method according to claim 2 , wherein the horizontal direction transform type of a subblock is determined based on a width of the subblock, and the vertical direction transform type of the subblock is determined based on a height of the subblock.
5. A video encoding method comprising:
determining whether a candidate intra prediction mode is a same intra prediction mode as an intra prediction mode of a current block;
deriving the intra prediction mode of the current block based on the determination; and
performing intra prediction on the current block based on a reference sample line of the current block and the derived intra prediction mode, wherein
when a difference between the intra prediction mode of a top neighboring block and the intra prediction mode of a left neighboring block is 64, at least one among the candidate intra prediction modes is derived by adding or subtracting 2 to or from a maximum value.
6. The method according to claim 5 , further comprising the step of determining whether or not to partition the current block into a plurality of subblocks, wherein
when the current block is partitioned into a plurality of subblocks, the plurality of subblocks shares one intra prediction mode, and
a horizontal direction transform type and a vertical direction transform type of a subblock are determined based on a shape of the subblock.
7. The method according to claim 6 , wherein transform is omitted for some of the plurality of subblocks.
8. The method according to claim 6 , wherein the horizontal direction transform type of a subblock is determined based on a width of the subblock, and the vertical direction transform type of the subblock is determined based on a height of the subblock.
9. A decoder, comprising:
a memory, for storing instructions executable by a processor,
the processor, for performing the instructions to execute operations of:
determining whether a candidate intra prediction mode is a same intra prediction mode as an intra prediction mode of a current block;
deriving the intra prediction mode of the current block based on the determination; and
performing intra prediction on the current block based on a reference sample line of the current block and the derived intra prediction mode, wherein
when a difference between the intra prediction mode of a top neighboring block and the intra prediction mode of a left neighboring block is 64, at least one among the candidate intra prediction modes is derived by adding or subtracting 2 to or from a maximum value.
10. The decoder according to claim 9 , wherein the processor is further configured to perform an operation of determining whether or not to partition the current block into a plurality of subblocks, wherein
when the current block is partitioned into a plurality of subblocks, the plurality of subblocks shares one intra prediction mode, and
a horizontal direction transform type and a vertical direction transform type of a subblock are determined based on a shape of the subblock.
11. The decoder according to claim 10 , wherein inverse transform is omitted for some of the plurality of subblocks.
12. The decoder according to claim 10 , wherein the horizontal direction transform type of a subblock is determined based on a width of the subblock, and the vertical direction transform type of the subblock is determined based on a height of the subblock.
13. An encoder, comprising:
a memory, for storing instructions executable by a processor,
the processor, for performing the instructions to execute operations of:
determining whether a candidate intra prediction mode is a same intra prediction mode as an intra prediction mode of a current block;
deriving the intra prediction mode of the current block based on the determination; and
performing intra prediction on the current block based on a reference sample line of the current block and the derived intra prediction mode, wherein
when a difference between the intra prediction mode of a top neighboring block and the intra prediction mode of a left neighboring block is 64, at least one among the candidate intra prediction modes is derived by adding or subtracting 2 to or from a maximum value.
14. The encoder according to claim 13 , wherein the processor is further configured to perform an operation of determining whether or not to partition the current block into a plurality of subblocks, wherein
when the current block is partitioned into a plurality of subblocks, the plurality of subblocks shares one intra prediction mode, and
a horizontal direction transform type and a vertical direction transform type of a subblock are determined based on a shape of the subblock.
15. The encoder according to claim 14 , wherein transform is omitted for some of the plurality of subblocks.
16. The encoder according to claim 14 , wherein the horizontal direction transform type of a subblock is determined based on a width of the subblock, and the vertical direction transform type of the subblock is determined based on a height of the subblock.