Method and device for sharing a candidate list

A method for decoding a video signal comprising:

• deriving, based on a position and a size of a first prediction block, at least one merging candidate relating to the first prediction block, a coding block comprising the first prediction block, and a second prediction block;
• generating a first merging candidate list for the first prediction block based on the merging candidate;
• obtaining prediction samples of the first prediction block based on the first merging candidate list;
• obtaining quantized coefficients of a transform block from the video signal;
• obtaining residual samples of the transform block using the quantized coefficients;
• and
• obtaining reconstruction samples based on the residual samples and the prediction samples,
• wherein when the size of the block indicated by parallel merge level information is equal to or greater than a first size and the size of the coding block which comprises the first prediction unit is equal to a second size, the position of the first prediction block is set equal to the position of the coding block and a size of the first prediction block is set equal to the size of the coding block, and
• wherein the first merging candidate list for the first prediction block is equivalent to a second merging candidate list for the second prediction block included in the coding block with the first prediction block, and the parallel merge level information represents a size of the block to which parallel merge processing is applicable.