Method and apparatus for encoding/decoding video, and recording medium storing bit stream
The present invention relates to an image encoding/decoding method and apparatus. The image decoding method according to the present invention may comprise reconstructing an intra prediction mode of a current block, determining a reference sample for intra prediction of the current block, and generating a prediction block of the current block by performing the intra prediction on the current block on the basis of the intra prediction mode and the reference sample. The determining of the reference sample or the intra prediction may be performed on the basis of a shape of the current block.
1 . A method of decoding an image performed by an image decoding device, the method comprising:
determining whether an intra prediction mode of a current block is included in at least one MPM list;
obtaining, in response to the intra prediction mode of the current block being included in the at least one MPM list, the intra prediction mode of the current block based on the at least one MPM list;
obtaining a prediction block of the current block by performing intra prediction of the current block based on the intra prediction mode,
wherein the at least one MPM list includes a first MPM list and a second MPM list,
wherein the first MPM list and the second MPM list are configured in different ways,
wherein the first MPM list includes a non-directional mode,
wherein the second MPM list does not include the non-directional mode included in the first MPM list,
wherein, in response to intra prediction modes of a left neighboring block and a top neighboring block of the current block being directional modes, the second MPM list includes an intra prediction mode that is different from an intra prediction mode of the left neighboring block by a predetermined offset k and an intra prediction mode that is different from an intra prediction mode of the top neighboring block by the predetermined offset k, and
wherein the intra prediction mode of the left neighboring block and the intra prediction mode of the top neighboring block are different from each other.
2 . The method of claim 1 ,
wherein one MPM list is selected from the at least one MPM list based on information signaled through a bitstream.
3 . The method of claim 1 ,
wherein obtaining the prediction block of the current block includes:
obtaining a modified intra prediction mode by modifying the intra prediction mode; and
obtaining the prediction block of the current block using the modified intra prediction mode.
4 . The method of claim 3 ,
wherein the modified intra prediction mode is obtained by increasing or decreasing the intra prediction mode by an integer N according to a size comparison result of the intra prediction mode.
5 . The method of claim 1 ,
wherein the method further includes obtaining a reference sample for the intra prediction of the current block, and
wherein the prediction block of the current block is obtained as a result of performing the intra prediction based on the intra prediction mode and the reference sample.
6 . The method of claim 5 ,
wherein obtaining the reference sample for the intra prediction of the current block includes selecting one reference sample line from a plurality of reference sample lines, and
wherein one reference sample line is selected based on whether a top boundary of the current block corresponds to a boundary of a current coding tree block to which the current block belongs.
7 . A method of encoding an image performed by an image encoding device, the method comprising:
obtaining an intra prediction mode of a current block;
obtaining a prediction block of the current block by performing intra prediction of the current block based on the intra prediction mode,
determining whether the intra prediction mode of the current block is included in at least one MPM list; and
encoding, in response to the intra prediction mode of the current block is included in the at least one MPM list, the intra prediction mode of the current block based on the at least one MPM list,
wherein the at least one MPM list includes a first MPM list and a second MPM list,
wherein the first MPM list and the second MPM list are configured in different ways,
wherein the first MPM list includes a non-directional mode,
wherein the second MPM list does not include the non-directional mode included in the first MPM list,
wherein, in response to intra prediction modes of a left neighboring block and a top neighboring block of the current block being directional modes, the second MPM list includes an intra prediction mode that is different from an intra prediction mode of the left neighboring block by a predetermined offset k and an intra prediction mode that is different from an intra prediction mode of the top neighboring block by the predetermined offset k, and
wherein the intra prediction mode of the left neighboring block and the intra prediction mode of the top neighboring block are different from each other.
8 . The method of claim 7 ,
wherein encoding the intra prediction mode of the current block includes encoding information for selecting one MPM list from the at least one MPM list.
9 . The method of claim 7 ,
wherein obtaining the prediction block of the current block includes:
obtaining a modified intra prediction mode by modifying the intra prediction mode; and
obtaining the prediction block of the current block using the modified intra prediction mode.
10 . The method of claim 9 ,
wherein the modified intra prediction mode is obtained by increasing or decreasing the intra prediction mode by an integer N according to a size comparison result of the intra prediction mode.
11 . The method of claim 7 ,
wherein the method further includes obtaining a reference sample for the intra prediction of the current block, and
wherein the prediction block of the current block is obtained as a result of performing the intra prediction based on the intra prediction mode and the reference sample.
12 . The method of claim 11 ,
wherein obtaining the reference sample for the intra prediction of the current block includes selecting one reference sample line from a plurality of reference sample lines, and
wherein one reference sample line is selected based on whether a top boundary of the current block corresponds to a boundary of a current coding tree block to which the current block belongs.
13 . A method of transmitting a bitstream generated by an encoding method, the encoding method comprising:
obtaining an intra prediction mode of a current block;
obtaining a prediction block of the current block by performing intra prediction of the current block based on the intra prediction mode,
determining whether the intra prediction mode of the current block is included in at least one MPM list;
encoding, in response to the intra prediction mode of the current block is included in the at least one MPM list, the intra prediction mode of the current block into the bitstream based on the at least one MPM list; and
transmitting the bitstream,
wherein the at least one MPM list includes a first MPM list and a second MPM list,
wherein the first MPM list and the second MPM list are configured in different ways,
wherein the first MPM list includes a non-directional mode,
wherein the second MPM list does not include the non-directional mode included in the first MPM list,
wherein, in response to intra prediction modes of a left neighboring block and a top neighboring block of the current block being directional modes, the second MPM list includes an intra prediction mode that is different from an intra prediction mode of the left neighboring block by a predetermined offset k and an intra prediction mode that is different from an intra prediction mode of the top neighboring block by the predetermined offset k, and
wherein the intra prediction mode of the left neighboring block and the intra prediction mode of the top neighboring block are different from each other.