Method for decoding video using in-loop filter, and device therefor

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.

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.