Inter-prediction mode-based image processing method and device therefor
Disclosed are a method for encoding a video signal and a device therefor. Specifically, a method for decoding an image based on an inter prediction mode comprises: generating a merging candidate list by using a spatial merge candidate and a temporal merge candidate of a current block; obtaining a merge index indicating a certain merge candidate in the merging candidate list; and generating a prediction block of the current block by using motion information of the certain merge candidate, wherein the generating of the merging candidate list may include adding a first merge candidate indicating a collocated block specified by motion information of the spatial merge candidate to the merging candidate list if a reference picture of the spatial merge candidate is same as a predetermined picture.
1. A method for decoding an image by a device based on an inter prediction mode, comprising:
obtaining a reference picture index and a motion vector of a neighboring block of a current block;
deriving a collocated block specified by the motion vector of the neighboring block, based on that a reference picture represented by the reference picture index of the neighboring block is same with a collocated picture;
generating a merging candidate list by adding the collocated block to the merge candidate list;
obtaining a merge index indicating a merge candidate in the merging candidate list; and
generating a prediction block of the current block based on motion information of the merge candidate,
wherein the collocated picture is determined in a slice header of a slice including the current block, and
wherein the collocated block is set to a block indicated by an L0 motion vector within the collocated picture based on that an L0 reference picture of the neighboring block is same with the collocated picture, and the collocated block is set to a block indicated by an L1 motion vector within the collocated picture based on that the L0 reference picture is different from the collocated picture, a slice type of the neighboring block is B-slice, and an L1 reference picture of the neighboring block is same with the collocated picture.
2. The method of claim 1 ,
wherein the neighboring block is located at a bottom of a left side of the current block.
3. A method for encoding an image by a device based on an inter prediction mode, comprising:
obtaining a reference picture index and a motion vector of a neighboring block of a current block;
deriving a collocated block specified by the motion vector of the neighboring block, based on that a reference picture represented by the reference picture index of the neighboring block is same with a collocated picture;
generating a merging candidate list by adding the collocated block to the merge candidate list;
generating prediction blocks of the current block based on motion information of merge candidates included in the merging candidate list;
generating a merge index indicating a merge candidate selected among the merge candidates included the merging candidate list; and
defining the collocated picture in a slice header of a slice including the current block,
wherein the collocated block is set to a block indicated by an L0 motion vector within the collocated picture based on that an L0 reference picture of the neighboring block is same with the collocated picture, and the collocated block is set to a block indicated by an L1 motion vector within the collocated picture based on that the L0 reference picture is different from the collocated picture, a slice type of the neighboring block is B-slice, and an L1 reference picture of the neighboring block is same with the collocated picture.
4. The method of claim 3 ,
wherein the neighboring block of the current block is located at a bottom of a left side of the current block.
5. A non-transitory decoder-readable storage medium for storing a bitstream generated according to the method of claim 3 .