Method and apparatus for processing video signal
A method for decoding a video according to the present invention may comprise: deriving a reference sample for a current block, determining an intra prediction mode of the current block, and obtaining a prediction sample for the current block by using the reference sample and the intra prediction mode.
1. A method for decoding a video, the method comprising:
determining an intra prediction mode of a current block;
obtaining a prediction sample at a target location in the current block based on a weighted sum of a first prediction sample and a second prediction sample when the intra prediction mode is a Planar mode, the first prediction sample being obtained by using at least one reference sample having a same y-coordinate as the target location and the second prediction sample being obtained by using at least one reference sample having a same x-coordinate as the target location;
obtaining a residual sample of the current block; and
reconstructing the current block based on the prediction sample and the residual sample,
wherein if the prediction sample is included in a first region of the current block, the prediction sample is obtained by further usage of a first value derived by a weighted sum of a top reference sample and a left reference sample, and
wherein if the prediction sample is included in a second region of the current block, the prediction sample is obtained by further usage of a second value derived by one of the top reference sample and the left reference sample.
2. The method of claim 1 , wherein the at least one reference sample having the same y-coordinate as the target location comprises a right reference sample derived based on the left reference sample and the top reference sample, and
wherein the at least one reference sample having the same x-coordinate as the target location comprises a bottom reference sample derived based on the top reference sample and the left reference sample.
3. The method of claim 1 , wherein at least one of a width or a height of the current block is greater than 4.
4. The method of claim 1 , wherein the first value is derived by applying a first weight to the top reference sample and applying a second weight to the left reference sample, and the first weight and the second weight is determined based on a coordinate of the target location.
5. A method for encoding a video, the method comprising:
obtaining a prediction sample at a target location in a current block based on a weighted sum of a first prediction sample and a second prediction sample when an intra prediction mode is a Planar mode, the first prediction sample being obtained by using at least one reference sample having a same y-coordinate as the target location and a second prediction sample being obtained by using at least one reference sample having a same x-coordinate as the target location; and
obtaining a residual sample of the current block by subtracting the prediction sample from an original sample,
wherein if the prediction sample is included in a first region of the current block, the prediction sample is obtained by further usage of a first value derived by a weighted sum of a top reference sample and a left reference sample, and
wherein if the prediction sample is included in a second region of the current block, the prediction sample is obtained by further usage of a second value derived by one of the top reference sample and the left reference sample.
6. The method of claim 5 , wherein the at least one reference sample having the same y-coordinate as the target location comprises a right reference sample derived based on the left reference sample and the top reference sample, and
wherein the at least one reference sample having the same x-coordinate as the target location comprises a bottom reference sample derived based on the top reference sample and the left reference sample.
7. The method of claim 5 , wherein at least one of a width or a height of the current block is greater than 4.
8. The method of claim 5 , wherein the first value is derived by applying a first weight to the top reference sample and applying a second weight to the left reference sample, and the first weight and the second weight is determined based on a coordinate of the target location.
9. A non-transitory computer-readable medium for storing compressed video data associated with a video signal, the compressed video data comprising:
information for determining an intra prediction mode of a current block,
wherein a prediction sample at a target location in the current block is obtained based on a weighted sum of a first prediction sample and a second prediction sample when the intra prediction mode is a Planar mode, the first prediction sample being obtained by using at least one reference sample having a same y-coordinate as the target location and a second prediction sample being obtained by using at least one reference sample having a same x-coordinate as the target location,
wherein the current block is reconstructed based on a residual sample and the prediction sample,
wherein if the prediction sample is included in a first region of the current block, the prediction sample is obtained by further usage of a first value derived by a weighted sum of a top reference sample and a left reference sample, and
wherein if the prediction sample is included in a second region of the current block, the prediction sample is obtained by further usage of a second value derived by one of the top reference sample and the left reference sample.