Method and apparatus for processing video signal
A method for processing a video according to the present invention may comprise: generating a plurality of Most Probable Mode (MPM) candidates; determining whether there is an MPM candidate identical to an intra-prediction mode of a current block among the plurality of MPM candidates; obtaining the intra-prediction mode of the current block, based on a result of the determining; and performing an intra-prediction for the current block, based on the intra-prediction mode of the current block.
1. A method for decoding a video, the method comprising:
determining a reference sample line for a current block among one or more reference sample line candidates; and
performing intra prediction for the current block based on reference samples in the reference sample line,
wherein a number of the one or more reference sample line candidates is determined based on information signaled at a sequence level,
wherein in response to a determination that a non-neighboring reference sample line is the reference sample line for the current block among the one or more reference sample line candidates, a non-directional mode of a Planar mode is not selectable as an intra prediction mode of the current block,
wherein in response to a determination that the DC mode is as the intra prediction mode of the current block, a prediction sample of the current block is obtained based on an average value of reference samples included in the reference sample line,
wherein a number of the reference samples used to derive the average value is the same between when the non-neighboring reference sample line is determined as the reference sample line for the current block and when a neighboring reference sample line is determined as the reference sample line for the current block,
wherein, in one of a case that the current block is a coding block of a square shape and a case that the current block is one of partitions of a non-square shape generated by partitioning the coding block, the intra-prediction for the current block is performed by using only the neighboring reference sample line, and
wherein, in the other case, the intra-prediction for the current block is performed by using selected one among the neighboring reference sample line and non-neighboring reference sample lines.
2. The method of claim 1 , wherein the reference sample line for the current block is determined based on index information specifying one among one or more reference sample line candidates, and
wherein the reference sample line candidates comprise the neighboring reference sample line adjacent to the current block and the non-neighboring reference sample line not adjacent to the current block.
3. The method of claim 2 , wherein a number of reference samples included in the non-neighboring reference sample line is greater than a number of reference samples included in the neighboring reference sample line.
4. The method of claim 1 ,
wherein a number of reference samples included in the reference sample line is determined based on the shape of the current block.
5. The method of claim 1 ,
wherein a number of the top reference samples used to derive the average value is determined based on a width of the current block.
6. The method of claim 1 ,
wherein a number of the left reference samples used to derive the average value is determined based on a height of the current block.
7. The method of claim 1 ,
wherein the average value is calculated by weighted sum of the top reference samples and the left reference samples, and
wherein a first weight applied to the top reference samples and a second weight applied to the left reference samples are determined based on the shape of the current block.
8. A method for encoding a video, the method comprising:
determining a reference sample line for a current block among one or more reference sample line candidates; and
performing intra prediction for the current block based on reference samples in the reference sample line,
wherein information used to determine a number of the one or more reference sample line candidates is encoded at a sequence level,
wherein in response to a determination that a non-neighboring reference sample line is the reference sample line for the current block among the one or more reference sample line candidates, a non-directional mode of a Planar mode is not selectable as an intra prediction mode of the current block, and
wherein in response to a determination that the DC mode is as the intra prediction mode of the current block, a prediction sample of the current block is obtained based on an average value of reference samples included in the reference sample line,
wherein a number of the reference samples used to derive the average value is the same between when the non-neighboring reference sample line is determined as the reference sample line for the current block and when a neighboring reference sample line is determined as the reference sample line for the current block,
wherein, in one of a case that the current block is a coding block of a square shape and a case that the current block is one of partitions of a non-square shape generated by partitioning the coding block, the intra-prediction for the current block is performed by using only the neighboring reference sample line, and
wherein, in the other case, the intra-prediction for the current block is performed by using selected one among the neighboring reference sample line and non-neighboring reference sample lines.
9. The method of claim 8 , wherein index information specifying the reference sample line among one or more reference sample line candidates is encoded into a bitstream, and
wherein the reference sample line candidates comprise the neighboring-reference sample line adjacent to the current block and the non-neighboring reference sample line not adjacent to the current block.
10. The method of claim 9 , wherein a number of reference samples included in the non-neighboring reference sample line is greater than a number of reference samples included in the neighboring reference sample line.
11. The method of claim 8 ,
wherein the average value is calculated by weighted sum of the top reference samples and the left reference samples, and
wherein a first weight applied to the top reference samples and a second weight applied to the left reference samples are determined based on the shape of the current block.
12. A device for storing a compressed video data which being generated with program instructions, when the program instructions being executed, the device being configured to:
determine a reference sample line for a current block among one or more reference sample line candidates; and
perform intra prediction for the current block based on reference samples in the reference sample line,
wherein information used to determine a number of the one or more reference sample line candidates is encoded at a sequence level,
wherein in response to a determination that a non-neighboring reference sample line is the reference sample line for the current block among the one or more reference sample line candidates, a non-directional mode of a Planar mode is not selectable as an intra prediction mode of the current block, and
wherein in response to a determination that the DC mode is the intra prediction mode of the current block, a prediction sample of the current block is obtained based on an average value of reference samples included in the reference sample line,
wherein a number of the reference samples used to derive the average value is the same between when the non-neighboring reference sample line is determined as the reference sample line for the current block and when a neighboring reference sample line is determined as the reference sample line for the current block,
wherein, in one of a case that the current block is a coding block of a square shape and a case that the current block is one of partitions of a non-square shape generated by partitioning the coding block, the intra-prediction for the current block is performed by using only the neighboring reference sample line, and
wherein, in the other case, the intra-prediction for the current block is performed by using selected one among the neighboring reference sample line and non-neighboring reference sample lines.