Decoding a video signal using intra-prediction mode information

1. A method for decoding a video signal by a decoding apparatus, the method comprising:

receiving, by the decoding apparatus, the video signal;

obtaining, by the decoding apparatus, intra prediction mode information of a current block from the video signal; and

when the intra prediction mode information indicates a vertical prediction mode, decoding, by the decoding apparatus, the current block in the vertical prediction mode,

wherein the decoding comprises:

obtaining, by the decoding apparatus, a value of a top neighboring pixel adjacent to the current block,

obtaining, by the decoding apparatus, correlation parameter information from a difference between a value of a top-left neighboring pixel adjacent to the current block and a value of at least one left neighboring pixel adjacent to the current block, and

obtaining, by the decoding apparatus, a prediction value of a pixel in the current block using the value of the top neighboring pixel and the correlation parameter information,

wherein the pixel in the current block has a same x-coordinate as the top neighboring pixel.

2. The method of claim 1 , wherein the prediction value of the pixel in the current block is obtained from adding a value of the correlation parameter information to the value of the top neighboring pixel.

3. The method of claim 1 , wherein the decoding further comprises:

obtaining, by the decoding apparatus, residual information of the current block, and

reconstructing, by the decoding apparatus, the pixel in the current block using the residual information and the prediction value of the pixel in the current block.

4. The method of claim 1 , wherein the at least one left neighboring pixel has a same y-coordinate as the pixel in the current block.

5. The method of claim 1 , wherein the at least one left neighboring pixel corresponds to a left neighboring pixel adjacent to a left-bottom corner pixel of the current block.

6. The method of claim 5 , wherein the correlation parameter information is obtained by the following equation:

a

=

L

-

M

4

,

where a denotes the correlation parameter information, L denotes a value of the left neighboring pixel adjacent to the left-bottom corner pixel of the current block, and M denotes the value of the top-left neighboring pixel of the current block.

7. The method of claim 1 , wherein the correlation parameter information is obtained by the following equation:

a

=

∑

x

i

⁢

y

i

-

y

0

⁢

∑

x

i

∑

x

i

2

,

where a denotes the correlation parameter information, x i denotes a vertical position of the pixel in the current block, y i denotes a value of an i-th pixel from top of the at least one left neighboring pixel adjacent to the current block, and y 0 denotes the value of the top-left neighboring pixel adjacent to the current block.

8. The method of claim 1 , wherein the current block is one of a 16×16 block, an 8×8 block, or a 4×4 block.

9. An apparatus configured to decode a video signal, the apparatus comprising:

a decoding apparatus configured to:

receive the video signal;

obtain intra prediction mode information of a current block from the video signal; and

when the intra prediction mode information indicates a vertical prediction mode, decode the current block in the vertical prediction mode,

wherein the decoding comprises:

obtaining, by the decoding apparatus, a value of a top neighboring pixel adjacent to the current block,

obtaining, by the decoding apparatus, correlation parameter information from a difference between a value of a top-left neighboring pixel adjacent to the current block and a value of at least one left neighboring pixel adjacent to the current block, and

obtaining, by the decoding apparatus, a prediction value of a pixel in the current block using the value of the top neighboring pixel and the correlation parameter information,

wherein the pixel in the current block has a same x-coordinate as the top neighboring pixel.

10. The apparatus of claim 9 , wherein the prediction value of the pixel in the current block is obtained from adding a value of the correlation parameter information to the value of the top neighboring pixel.

11. The apparatus of claim 9 , wherein the decoding further comprises:

obtaining, by the decoding apparatus, residual information of the current block, and

reconstructing, by the decoding apparatus, the pixel in the current block using the residual information and the prediction value of the pixel in the current block.

12. The apparatus of claim 9 , wherein the at least one left neighboring pixel has a same y-coordinate as the pixel in the current block.

13. The apparatus of claim 9 , wherein the at least one left neighboring pixel corresponds to a left neighboring pixel adjacent to a left-bottom corner pixel of the current block.

14. The apparatus of claim 13 , wherein the correlation parameter information is obtained by the following equation:

a

=

L

-

M

4

,

where a denotes the correlation parameter information, L denotes a value of the left neighboring pixel adjacent to the left-bottom corner pixel of the current block, and M denotes the value of the top-left neighboring pixel of the current block.

15. The apparatus of claim 9 , wherein the correlation parameter information is obtained by the following equation:

a

=

∑

x

i

⁢

y

i

-

y

0

⁢

∑

x

i

∑

x

i

2

,

where a denotes the correlation parameter information, x i denotes a vertical position of the pixel in the current block, y i denotes a value of an i-th pixel from top of the at least one left neighboring pixel adjacent to the current block, and y 0 denotes the value of the top-left neighboring pixel adjacent to the current block.

16. The apparatus of claim 9 , wherein the current block is one of a 16×16 block, an 8×8 block, or a 4×4 block.