Decoding device and method for predicting block partitioned into random shape
A method and a device for inversely transforming transform coefficients of a current block are disclosed. A method for predicting a current block according to a first mode, includes the steps of: on the basis of a partition mode syntax element, partitioning the current block into non-rectangular blocks; determining an intra-predicted intra block and an inter-predicted inter block among the non-rectangular blocks; and deriving prediction samples of a first area including the inter block on the basis of motion information, and deriving prediction samples of a second area including the intra block on the basis of an intra prediction mode.
1. A method of predicting a current block based on a first mode, the method comprising:
partitioning the current block into non-rectangular blocks based on a partition mode syntax element;
determining an intra block to be intra-predicted and an inter block to be inter-predicted among the non-rectangular blocks;
deriving inter prediction sample values of a first area including the inter block based on motion information;
deriving intra prediction sample values of a second area including the intra block based on an intra prediction mode;
deriving an intra weight and an inter weight to be applied to a to-be-predicted target sample by considering a distance between the target sample among samples within the current block and a partition edge of the non-rectangular blocks within the current block; and
deriving a weighted prediction value of the target sample based on a weighted intra prediction value obtained by applying the intra weight to an intra prediction sample value of the target sample and a weighted inter prediction value obtained by applying the inter weight to an inter prediction sample value of the target sample,
wherein deriving the intra prediction sample values of the second area comprises:
constructing an intra prediction mode candidate list by selecting a part of total available intra prediction modes, wherein the intra prediction mode candidate list includes one or more directional modes corresponding to an angle formed by the partition edge of the non-rectangular blocks, and a number of intra prediction modes included in intra prediction mode candidate list is less than a number of the total available intra prediction modes; and
selecting the intra prediction mode from the intra prediction mode candidate list.
2. The method of claim 1 , wherein the intra block and the inter block are determined among the non-rectangular blocks based on the angle formed by the partition edge of the non-rectangular blocks and a horizontal direction of the current block.
3. The method of claim 1 , wherein the intra block and the inter block are determined among the non-rectangular blocks based on a perpendicular distance from a center position of the current block to a partition edge of the non-rectangular blocks.
4. The method of claim 1 ,
wherein the intra prediction sample values of the intra block are derived by using the inter prediction sample values of the inter block as reference samples.
5. The method of claim 4 , wherein the prediction samples of the intra block are derived by using, as reference samples, prediction samples neighboring a partition edge of the non-rectangular blocks among the prediction samples of the inter block.
6. The method of claim 1 , further comprising:
determining whether to apply the first mode based on a number of intra-predicted neighbor blocks among neighbor blocks of the current block,
wherein partitioning the current block into the non-rectangular blocks is performed when it is determined that the first mode is applied.
7. The method of claim 1 , wherein the intra weight and the inter weight are derived by further considering whether neighbor blocks of the current block have been inter-predicted or intra-predicted.
8. A video encoding method for predicting a current block based on a first mode, the method comprising:
partitioning the current block into non-rectangular blocks;
determining an intra block to be intra-predicted and an inter block to be inter-predicted among the non-rectangular blocks;
deriving inter prediction sample values of a first area including the inter block based on motion information;
deriving intra prediction sample values of a second area including the intra block based on an intra prediction mode; and
encoding the current block based on the inter prediction sample values of the first area and the intra prediction sample values of the second area,
wherein deriving the intra prediction sample values of the second area comprises:
constructing an intra prediction mode candidate list by selecting a part of total available intra prediction modes, wherein the intra prediction mode candidate list includes one or more directional modes corresponding to an angle formed by a partition edge of the non-rectangular blocks, and a number of intra prediction modes included in intra prediction mode candidate list is less than a number of the total available intra prediction modes; and
selecting the intra prediction mode from the intra prediction mode candidate list, and
wherein encoding the current block comprises:
deriving an intra weight and an inter weight to be applied to a to-be-predicted target sample by considering a distance between the target sample among samples within the current block and the partition edge of the non-rectangular blocks within the current block, and
deriving a weighted prediction value of the target sample based on a weighted intra prediction value obtained by applying the intra weight to an intra prediction sample value of the target sample and a weighted inter prediction value obtained by applying the inter weight to an inter prediction sample value of the target sample.
9. The method of claim 8 , wherein the intra block and the inter block are determined based on the angle formed by the partition edge of the non-rectangular blocks and a horizontal direction of the current block.
10. The method of claim 8 , wherein the intra block and the inter block are determined based on a perpendicular distance from a center position of the current block to a partition edge of the non-rectangular blocks.
11. The method of claim 8 ,
wherein the intra prediction sample values of the intra block are derived by using the inter prediction sample values of the inter block as reference samples.
12. The method of claim 11 , wherein the intra prediction sample values of the intra block are derived by using, as reference samples, prediction samples neighboring the partition edge of the non-rectangular blocks among the inter prediction sample values of the inter block.
13. The method of claim 8 , further comprising:
determining whether to apply the first mode based on a number of intra-predicted neighbor blocks among neighbor blocks of the current block,
wherein the current block is partitioned into the non-rectangular blocks when it is determined that the first mode is applied.
14. The method of claim 8 , wherein the intra weight and the inter weight are derived by further considering whether neighbor blocks of the current block are inter-predicted or intra-predicted.
15. A method for transmitting a bitstream containing encoded video data, the method comprising:
generating the bitstream by encoding a current block; and
transmitting the bitstream to a video decoding apparatus,
wherein generating the bitstream comprises:
partitioning the current block into non-rectangular blocks;
determining an intra block to be intra-predicted and an inter block to be inter-predicted among the non-rectangular blocks;
deriving inter prediction sample values of a first area including the inter block based on motion information;
deriving intra prediction sample values of a second area including the intra block based on an intra prediction mode; and
encoding the current block based on the inter prediction sample values of the first area and the intra prediction sample values of the second area,
wherein deriving the intra prediction sample values of the second area comprises:
constructing an intra prediction mode candidate list by selecting a part of total available intra prediction modes, wherein the intra prediction mode candidate list includes one or more directional modes corresponding to an angle formed by a partition edge of the non-rectangular blocks, and a number of intra prediction modes included in intra prediction mode candidate list is less than a number of the total available intra prediction modes; and
selecting the intra prediction mode from the intra prediction mode candidate list, and
wherein encoding the current block comprises:
deriving an intra weight and an inter weight to be applied to a to-be-predicted target sample by considering a distance between the target sample among samples within the current block and the partition edge of the non-rectangular blocks within the current block, and
deriving a weighted prediction value of the target sample based on a weighted intra prediction value obtained by applying the intra weight to an intra prediction sample value of the target sample and a weighted inter prediction value obtained by applying the inter weight to an inter prediction sample value of the target sample.