Method for decoding video using in-loop filter, and device therefor
The present invention provides a method and apparatus for encoding/decoding an image and for adjusting a reconstructed pixel by scaling an offset of an in-loop filter having a scaled offset value. The method includes: obtaining information of a scale default value of a current block from a bitstream; obtaining offset parameter merge information of the current block from the bitstream; obtaining the offset parameter of the current block on the basis of the offset parameter merge information; determining whether a scale residual value of the current block is obtained from the bitstream on the basis of the offset parameter merge information; obtaining a scale value on the basis of the scale default value and the scale residual value; scaling an offset on the basis of the offset parameter and the scale value; and adjusting a pixel value of the current block on the basis of the scaled offset.
1. A method for decoding a video signal, the method comprising:
obtaining information of a scale default value of a current block from a bitstream;
obtaining offset parameter merge information of the current block from the bitstream, wherein the offset parameter merge information indicates whether or not an offset parameter of the current block is the same as at least one of neighboring blocks adjacent to the current block;
obtaining the offset parameter of the current block on the basis of the offset parameter merge information;
determining whether or not a scale residual value of the current block is obtained from the bitstream on the basis of the offset parameter merge information, wherein when the offset parameter merge information indicates that the offset parameter of the current block is different from the neighboring blocks adjacent to the current block, the scale residual value is obtained from the bitstream;
obtaining a scale value on the basis of the scale default value and the scale residual value;
scaling an offset on the basis of the offset parameter and the scale value; and
adjusting a pixel value of the current block on the basis of the scaled offset.
2. The method of claim 1 , wherein when the offset parameter merge information indicates that the offset parameter of the current block is the same as at least one of the neighboring blocks adjacent to the current block, the scaled offset is derived from at least one of the neighboring blocks.
3. The method of claim 1 , wherein a unit of signaling the scale default value and a unit of signaling the scale residual value are different from each other.
4. The method of claim 1 , wherein the scale residual value is obtained for each color component and each offset type.
5. The method of claim 4 , wherein a scale residual value of a predetermined color component is derived to be the same as a scale residual value of a previous color component.
6. The method of claim 4 , wherein a scale residual value of a predetermined offset type of a predetermined color component is used as a scale residual value of a remaining offset type of the predetermined color component.
7. The method of claim 4 , wherein the scale residual value indicates a difference between scale residual values of a predetermined color component and of a previous color component, or a difference between scale residual values of a predetermined offset type and of a previous offset type.
8. The method of claim 2 , wherein a neighboring block includes at least one of a spatial neighboring block spatially adjacent to the current block, and a temporal neighboring block temporally adjacent to the current block.
9. The method of claim 8 , wherein the offset parameter of the current block is derived from a neighboring block indicated by index information parsed from the bitstream.
10. A method for decoding a video signal, the method comprising:
obtaining offset parameter merge information and scale parameter merge information of a current block from a bitstream, wherein the offset parameter merge information indicates whether or not an offset parameter of the current block is the same as at least one of neighboring blocks adjacent to the current block, and the scale parameter merge information indicates whether or not a scale parameter of the current block is the same as at least one of the neighboring blocks adjacent to the current block;
obtaining the offset parameter of the current block on the basis of the offset parameter merge information;
obtaining the scale parameter of the current block on the basis of the scale parameter merge information;
scaling an offset on the basis of the offset parameter and the scale parameter; and
adjusting a pixel value of the current block on the basis of the scaled offset.
11. The method of claim 10 , wherein the offset parameter of the current block is obtained from the bitstream or at least one of the neighboring blocks adjacent to the current block depending on the offset parameter merge information, and
the scale parameter of the current block is obtained from the bitstream or at least one of the neighboring blocks adjacent to the current block depending on the scale parameter merge information.
12. The method of claim 10 , wherein a scale value for scaling the offset is obtained on the basis of a scale default value and a scale residual value indicated by the scale parameter.
13. An apparatus for decoding a video signal, the apparatus comprising:
an offset merge information parsing unit obtaining offset parameter merge information of a current block from a bitstream, wherein the offset parameter merge information indicates whether or not an offset parameter of the current block is the same as at least one of neighboring blocks adjacent to the current block;
an offset parameter reconstruction unit obtaining the offset parameter of the current block on the basis of the offset parameter merge information;
a scale parameter reconstruction unit determining whether or not a scale parameter of the current block is obtained from the bitstream on the basis of the offset parameter merge information, wherein when the offset parameter merge information indicates that the offset parameter of the current block is different from the neighboring blocks adjacent to the current block, a scale residual value is obtained from the bitstream;
an offset determination unit obtaining a scale value on the basis of a scale default value and the scale residual value, and scaling an offset on the basis of the offset parameter and the scale value; and
an offset application unit adjusting a pixel value of the current block on the basis of the scaled offset.
14. The apparatus of claim 13 , wherein when the offset parameter merge information indicates that the offset parameter of the current block is the same as at least one of the neighboring blocks adjacent to the current block, the scale parameter reconstruction unit derives the scale residual value of the current block from at least one of the neighboring blocks.
15. The apparatus of claim 13 , wherein a unit of signaling the scale default value and a unit of signaling the scale residual value are different from each other.
16. The apparatus of claim 15 , wherein the scale parameter reconstruction unit obtains the scale residual value for each color component and each offset type.
17. The apparatus of claim 16 , wherein a scale residual value of a predetermined color component is derived to be the same as a scale residual value of a previous color component.
18. The apparatus of claim 16 , wherein a scale residual value of a predetermined offset type of a predetermined color component is used as a scale residual value of a remaining offset type of the predetermined color component.
19. The apparatus of claim 14 , wherein a neighboring block includes at least one of a spatial neighboring block spatially adjacent to the current block, and a temporal neighboring block temporally adjacent to the current block.
20. The apparatus of claim 19 , wherein the offset parameter reconstruction unit derives the offset parameter of the current block from a neighboring block indicated by index information parsed from the bitstream.