Planar prediction mode
New intra planar modes are introduced for predicting digital video data. As part of the new intra planar modes, various methods are offered for predicting a first sample within a prediction unit, where the first sample is needed for referencing to when processing the new intra planar modes. And once the first sample is successfully predicted, the new intra planar modes are able to predict a sample of video data within the prediction unit by processing a bi-linear interpolation of four previously reconstructed reference samples.
1. A method for processing a video signal by a decoding apparatus, the method comprising:
obtaining, by the decoding apparatus, a first reference sample and a second reference sample by filtering samples of neighboring blocks of a current block, the first reference sample being obtained by a filter using at least three horizontally consecutive samples in an upper-right block and an upper block of the current block, and the second reference sample being obtained by a filter using at least three vertically consecutive samples in a left block and a left-lower block of the current block;
obtaining, by the decoding apparatus, a predicted value of a video data sample of the current block by a bi-linear interpolation using the first reference sample, the second reference sample, a third reference sample, and a fourth reference sample, the first reference sample being positioned in a same y-coordinate as the video data sample within a rightmost column of the current block for the bi-linear interpolation, the second reference sample being positioned in a same x-coordinate as the video data sample within a bottommost row of the current block for the bi-linear interpolation, the third reference sample being a reconstructed sample having the same y-coordinate as the video data sample in the left block, and the fourth reference sample being a reconstructed sample having the same x-coordinate as the video data sample in the upper block; and
reconstructing, by the decoding apparatus, the current block based on the predicted value.
2. The method according to claim 1 , wherein the at least three horizontally consecutive samples are consecutive around a boundary between the upper-right block and the upper block of the current block.
3. The method according to claim 1 , wherein the at least three vertically consecutive samples are consecutive around a boundary between the left block and the left-lower block of the current block.
4. The method according to claim 1 , wherein the first reference sample is obtained by the following equation:
T′={T —1 +( T<< 1)+ T +1 +2}>>2
where T′ denotes the first reference sample, T −1 , T, T +1 denote the at least three horizontally consecutive samples, << denotes a left-shift operation, and >> denotes a right-shift operation.
5. The method according to claim 1 , wherein the second reference sample is obtained by the following equation:
L′={L —1 +( L<< 1)+ L +1 +2}>>2
where L′ denotes the second reference sample, L −1 , L, L +1 denote the at least three vertically consecutive samples, << denotes a left-shift operation, and >> denotes a right-shift operation.
6. The method according to claim 1 , wherein the current block is coded in intra planar prediction mode.
7. The method according to claim 1 , wherein the bi-linear interpolation includes:
performing a first linear interpolation of the first reference sample and the third reference sample and a second linear interpolation of the second reference sample and the fourth reference sample, and
obtaining the predicted value by averaging a result of the first linear interpolation and a result of the second linear interpolation.
8. A decoding apparatus for processing a video signal, the decoding apparatus comprising:
an intra prediction unit configured to:
obtain a first reference sample and a second reference sample by filtering samples of neighboring blocks of a current block, the first reference sample being obtained by a filter using at least three horizontally consecutive samples in an upper-right block and an upper block of the current block, and the second reference sample being obtained by a filter using at least three vertically consecutive samples in a left block and a left-lower block of the current block, and
obtain a predicted value of a video data sample of the current block by a bi-linear interpolation using the first reference sample, the second reference sample, a third reference sample and a fourth reference sample, the first reference sample being positioned in a same y-coordinate as the video data sample within a rightmost column of the current block for the bi-linear interpolation, the second reference sample being positioned in a same x-coordinate as the video data sample within a bottommost row of the current block for the bi-linear interpolation, the third reference sample being a reconstructed sample having the same y-coordinate as the video data sample in the left block, and the fourth reference sample being a reconstructed sample having the same x-coordinate as the video data sample in the upper block; and
a reconstruction unit configured to reconstruct the current block based on the predicted value.
9. The decoding apparatus according to claim 8 , wherein the at least three horizontally consecutive samples are consecutive around a boundary between the upper-right block and the upper block of the current block.
10. The decoding apparatus according to claim 8 , wherein the at least three vertically consecutive samples are consecutive around a boundary between the left block and the left-lower block of the current block.
11. The decoding apparatus according to claim 8 , wherein the first reference sample is obtained by the following equation:
T′={T −1 +( T<< 1)+ T +1 +2}>>2
where T′ denotes the first reference sample, T −1 , T, T +1 denote the at least three horizontally consecutive samples, << denotes a left-shift operation, and >> denotes a right-shift operation.
12. The decoding apparatus according to claim 8 , wherein the second reference sample is obtained by the following equation:
L′={L −1 +( L<< 1)+ L +1 +2}>>2,
where L′ denotes the second reference sample, L −1 , L, L +1 denote the at least three vertically consecutive samples, << denotes a left-shift operation, and >> denotes a right-shift operation.
13. The decoding apparatus according to claim 8 , wherein the current block is coded in intra planar prediction mode.
14. The decoding apparatus according to claim 8 , wherein the bi-linear interpolation includes:
performing a first linear interpolation of the first reference sample and the third reference sample and a second linear interpolation of the second reference sample and the fourth reference sample, and
obtaining the predicted value by averaging a result of the first linear interpolation and a result of the second linear interpolation.
15. A method for processing a video signal by an encoding apparatus, the method comprising:
obtaining, by the encoding apparatus, a first reference sample and a second reference sample by filtering samples of neighboring blocks of a current block, the first reference sample being obtained by a filter using at least three horizontally consecutive samples in an upper-right block and an upper block of the current block, and the second reference sample being obtained by a filter using at least three vertically consecutive samples in a left block and a left-lower block of the current block;
obtaining, by the encoding apparatus, a predicted value of a video data sample of the current block by a bi-linear interpolation using the first reference sample, the second reference sample, a third reference sample, and a fourth reference sample, the first reference sample being positioned in a same y-coordinate as the video data sample within a rightmost column of the current block for the bi-linear interpolation, the second reference sample being positioned in a same x-coordinate as the video data sample within a bottommost row of the current block for the bi-linear interpolation, the third reference sample being a reconstructed sample having the same y-coordinate as the video data sample in the left block, and the fourth reference sample being a reconstructed sample having the same x-coordinate as the video data sample in the upper block; and
encoding, by the encoding apparatus, the current block based on the predicted value.
16. An encoding apparatus for processing a video signal, the encoding apparatus comprising:
an intra prediction unit configured to:
obtain a first reference sample and a second reference sample by filtering samples of neighboring blocks of a current block, the first reference sample being obtained by a filter using at least three horizontally consecutive samples in an upper-right block and an upper block of the current block, and the second reference sample being obtained by a filter using at least three vertically consecutive samples in a left block and a left-lower block of the current block,
obtain a predicted value of a video data sample of the current block by a bi-linear interpolation using the first reference sample, the second reference sample, a third reference sample and a fourth reference sample, the first reference sample being positioned in a same y-coordinate as the video data sample within a rightmost column of the current block for the bi-linear interpolation, the second reference sample being positioned in a same x-coordinate as the video data sample within a bottommost row of the current block for the bi-linear interpolation, the third reference sample being a reconstructed sample having the same y-coordinate as the video data sample in the left block, and the fourth reference sample being a reconstructed sample having the same x-coordinate as the video data sample in the upper block, and
encode the current block based on the predicted value.