Encoding and decoding method and device for video using determined intra prediction mode and reference samples on a reference line
Disclosed is a video signal processing method and device for encoding or decoding a video signal. More specifically, disclosed are a video signal processing method and a video signal processing device for performing the method, the method comprising: obtaining reference line information indicating a reference line for intra prediction of a current block among a plurality of reference lines comprising neighboring samples of the current block; determining, on the basis of the reference line information, an intra prediction mode for the current block among a plurality of intra prediction modes constituting an intra prediction mode set; and decoding the current block on the basis of a plurality of reference samples on the reference line according to the reference line information and the determined intra prediction mode, wherein the plurality of reference lines include a first reference line comprising neighboring samples on a line adjacent to the boundary of the current block and a second reference line comprising neighboring samples on a line spaced a distance corresponding to a predetermined number of samples apart from the boundary of the current block.
1. A non-transitory computer-readable medium storing a bitstream, the bitstream being decoded by a decoding method, wherein the decoding method, comprising:
obtaining reference line information indicating a reference line used for intra prediction of a current block among a plurality of reference lines configured with neighboring samples of the current block;
determining an intra prediction mode for the current block among a plurality of intra prediction modes configuring an intra prediction mode set based on the reference line information; and
decoding the current block based on a plurality of reference samples on a reference line according to the reference line information and the determined intra prediction mode,
wherein the plurality of reference lines comprise a first reference line configured with neighboring samples on a line adjacent to the boundary of the current block, and a second reference line configured with neighboring samples on a line spaced by a specific number of samples based on the boundary of the current block,
wherein when the reference line for intra prediction of the current block is the first reference line, the intra prediction mode set is a first intra prediction mode set,
wherein when the reference line for intra prediction of the current block is not the first reference line, the intra prediction mode set is a second intra prediction mode set configured with part of a plurality of intra prediction modes configuring the first intra prediction mode set,
wherein the second intra prediction mode set does not include a planar mode,
wherein the second intra prediction mode set is determined based on an intra prediction mode corresponding to at least one of neighboring blocks of the current block,
wherein the second intra prediction mode set includes at least one of a direct current mode (DC mode) and/or a plurality number of angular modes, and
wherein the plurality number of angular modes is a preset number of angular modes.
2. The non-transitory computer-readable medium storing the bitstream of claim 1 , wherein the determining of the intra prediction mode for the current block comprises:
receiving intra prediction mode information indicating the DC mode or any one of the preset number of angular modes included in the second intra prediction mode set; and
determining an intra prediction mode for the current block based on the intra prediction mode information.
3. The non-transitory computer-readable medium storing the bitstream of claim 1 , wherein the intra prediction mode set is determined based on a position of the current block in an upper level region including the current block.
4. The non-transitory computer-readable medium storing the bitstream of claim 3 , wherein when the current block is adjacent to an upper boundary of the upper level region, the reference line information is considered to indicate the first reference line,
wherein the intra prediction mode set for the current block is the first intra prediction mode set.
5. The non-transitory computer-readable medium storing the bitstream of claim 1 , wherein the first intra prediction mode set comprises a plurality of angular modes, the planar mode, and a direct current mode (DC mode).
6. The non-transitory computer-readable medium storing the bitstream of claim 1 , wherein the boundary of the current block is a left or upper boundary of the current block.
7. The non-transitory computer-readable medium storing the bitstream of claim 1 , wherein the specific number of samples is less than or equal to a preset number of samples.
8. The non-transitory computer-readable medium storing the bitstream of claim 7 , wherein the number of samples represents the number of integer pixels.
9. A device for decoding a video signal, the device comprising:
a processor,
wherein the processor is configured to:
obtain reference line information indicating a reference line used for intra prediction of a current block among a plurality of reference lines configured with neighboring samples of the current block,
determine an intra prediction mode for the current block among a plurality of intra prediction modes configuring an intra prediction mode set based on the reference line information, and
decode the current block based on a plurality of reference samples on a reference line according to the reference line information and the determined intra prediction mode,
wherein the plurality of reference lines comprise a first reference line configured with neighboring samples on a line adjacent to the boundary of the current block, and a second reference line configured with neighboring samples on a line spaced by a specific number of samples based on the boundary of the current block,
wherein when the reference line for intra prediction of the current block is the first reference line, the intra prediction mode set is a first intra prediction mode set,
wherein when the reference line for intra prediction of the current block is not the first reference line, the intra prediction mode set is a second intra prediction mode set configured with part of a plurality of intra prediction modes configuring the first intra prediction mode set,
wherein the second intra prediction mode set does not include a planar mode,
wherein the second intra prediction mode set is determined based on an intra prediction mode corresponding to at least one of neighboring blocks of the current block,
wherein the second intra prediction mode set includes at least one of a direct current mode (DC mode) and/or a plurality number of angular modes, and
wherein the plurality number of angular modes is a preset number of angular modes.
10. The device of claim 9 , wherein the processor configured to:
receive intra prediction mode information indicating the DC mode or any one of the preset number of angular modes included in the second intra prediction mode set, and
determine an intra prediction mode for the current block based on the intra prediction mode information.
11. The device of claim 9 , wherein the intra prediction mode set is determined based on a position of the current block in an upper level region including the current block.
12. The device of claim 11 , wherein when the current block is adjacent to an upper boundary of the upper level region, the reference line information is considered to indicate the first reference line,
wherein the intra prediction mode set for the current block is the first intra prediction mode set.
13. A device for encoding a video signal, the device comprising
a processor,
wherein the processor is configured to
obtain a bitstream to be decoded by a decoder using a decoding method,
wherein the decoding method comprising:
obtaining reference line information indicating a reference line used for intra prediction of a current block among a plurality of reference lines configured with neighboring samples of the current block;
determining an intra prediction mode for the current block among a plurality of intra prediction modes configuring an intra prediction mode set based on the reference line information; and
decoding the current block based on a plurality of reference samples on a reference line according to the reference line information and the determined intra prediction mode,
wherein the plurality of reference lines comprise a first reference line configured with neighboring samples on a line adjacent to the boundary of the current block, and a second reference line configured with neighboring samples on a line spaced by a specific number of samples based on the boundary of the current block,
wherein when the reference line for intra prediction of the current block is the first reference line, the intra prediction mode set is a first intra prediction mode set,
wherein when the reference line for intra prediction of the current block is not the first reference line, the intra prediction mode set is a second intra prediction mode set configured with part of a plurality of intra prediction modes configuring the first intra prediction mode set,
wherein the second intra prediction mode set does not include a planar mode,
wherein the second intra prediction mode set is determined based on an intra prediction mode corresponding to at least one of neighboring blocks of the current block,
wherein the second intra prediction mode set includes at least one of a direct current mode (DC mode) and/or a plurality number of angular modes, and
wherein the plurality number of angular modes is a preset number of angular modes.