Method and apparatus for processing video signal based on inter prediction

A method of encoding a video signal by an apparatus, comprising:

• generating a first merge candidate list of a current block based on a plurality of spatial candidates including a bottom left corner neighboring spatial candidate, a left neighboring spatial candidate, a top right corner neighboring spatial candidate, a top neighboring spatial candidate and a top left corner neighboring spatial candidate, and a temporal candidate of the current block, the plurality of spatial candidates preceding the temporal candidate in the first merge candidate list;
• generating a second merge candidate list by adding to the first merge candidate list a history-based candidate including motion information for a block decoded prior to the current block;
• generating a merge index indicating a merge candidate applied to the current block within the second merge candidate list;
• generating a prediction block of the current block based on motion information of the merge candidate indicated by the merge index;
• and
• generating a residual block of the current block based on the prediction block,
• wherein the generating of the second merge candidate list includes:
• performing a pruning check whether the history-based candidate has same motion information with the left neighboring spatial candidate and the top neighboring spatial candidate included in the first merge candidate list;
• and
• adding the history-based candidate only when the pruning checking indicates that the history-based candidate does not have same motion information with the left neighboring spatial candidate and the top neighboring spatial candidate included in the first merge candidate list, and
• wherein the pruning check is not performed for the bottom left corner neighboring spatial candidate, the top right corner neighboring spatial candidate and the top left corner neighboring spatial candidate included in the first merge candidate list.

A transmission method for data comprising a bitstream for an image, the method comprising:

• obtaining the bitstream for the image;
• and
• transmitting the data comprising the bitstream,
• wherein the bitstream is generated by performing the steps of:
• generating a first merge candidate list of a current block based on a plurality of spatial candidates including a bottom left corner neighboring spatial candidate, a left neighboring spatial candidate, a top right corner neighboring spatial candidate, a top neighboring spatial candidate and a top left corner neighboring spatial candidate, and a temporal candidate of the current block, the plurality of spatial candidates preceding the temporal candidate in the first merge candidate list;
• generating a second merge candidate list by adding to the first merge candidate list a history-based candidate including motion information for a block decoded prior to the current block;
• generating a merge index indicating a merge candidate applied to the current block within the second merge candidate list;
• generating a prediction block of the current block based on motion information of the merge candidate indicated by the merge index;
• and
• generating a residual block of the current block based on the prediction block, and
• wherein the generating of the second merge candidate list includes:
• performing a pruning check whether the history-based candidate has same motion information with the left neighboring spatial candidate and the top neighboring spatial candidate included in the first merge candidate list;
• and
• adding the history-based candidate only when the pruning checking indicates that the history-based candidate does not have same motion information with the left neighboring spatial candidate and the top neighboring spatial candidate included in the first merge candidate list, and
• wherein the pruning check is not performed for the bottom left corner neighboring spatial candidate, the top right corner neighboring spatial candidate and the top left corner neighboring spatial candidate included in the first merge candidate list.