Method and apparatus for processing video signal on basis of inter prediction
A method and device for processing a video signal are disclosed. More specifically, a method of processing a video signal based on inter prediction may comprise: deriving a motion vector predictor based on motion information of a neighboring block of a current block; deriving a motion vector difference of the current block based on layer information and index information; deriving a motion vector of the current block based on the motion vector predictor and the motion vector difference; generating a prediction block of the current block based on the motion vector of the current block; and generating a reconstructed block of the current block based on the prediction block and a residual block of the current block, wherein the layer information includes at least one syntax element indicating a layer group to which the current layer belongs.
1. A method of processing a video signal based on inter prediction, comprising:
deriving a motion vector predictor based on motion information of a neighboring block of a current block;
deriving a motion vector difference of the current block based on layer information and index information, wherein the layer information represents a current layer, which the motion vector difference used for the inter prediction of the current block belongs to, in a predefined layer structure in which at least one combination of horizontal and vertical components of the motion vector difference is divided into a plurality of layers, and the index information represents a specific combination of vertical and horizontal components of the motion vector difference within the current layer;
deriving a motion vector of the current block based on the motion vector predictor and the motion vector difference;
generating a prediction block of the current block based on the motion vector of the current block; and
generating a reconstructed block of the current block based on the prediction block and a residual block of the current block,
wherein the layer information includes at least one syntax element indicating a layer group to which the current layer belongs,
wherein the index information is binarized based on a truncated binarization scheme,
wherein deriving the motion vector difference further comprises:
obtaining a first syntax element representing whether an identification (ID) of the current layer is greater than 0,
obtaining a second syntax element indicating whether the current layer belongs to a first layer group when the ID of the current layer is greater than 0,
obtaining a third syntax element indicating whether the ID of the current layer is 1 or 2 when the current layer belongs to the first layer group, and
obtaining ID information indicating the ID of the current layer when the ID of the current layer is greater than 0, and
wherein the ID information is binarized based on an exponential Golomb code with order 1.
2. The method of claim 1 , wherein the ID of the current layer is determined as 3 when the current layer does not belong to the first layer group.
3. An apparatus for decoding a video signal based on inter prediction, comprising:
a memory configured to store the video signal; and
a processor coupled with the memory,
wherein the processor is configured to:
derive a motion vector predictor based on motion information of a neighboring block of a current block;
derive a motion vector difference of the current block based on layer information and index information, wherein the layer information represents a current layer, which the motion vector difference used for the inter prediction of the current block belongs to, in a predefined layer structure in which at least one combination of horizontal and vertical components of the motion vector difference is divided into a plurality of layers, and the index information represents a specific combination of vertical and horizontal components of the motion vector difference within the current layer;
derive a motion vector of the current block based on the motion vector predictor and the motion vector difference;
generate a prediction block of the current block based on the motion vector of the current block; and
generate a reconstructed block of the current block based on the prediction block and a residual block of the current block,
wherein the layer information includes at least one syntax element indicating a layer group to which the current layer belongs,
wherein the index information is binarized based on a truncated binarization scheme,
wherein deriving the motion vector difference further comprises:
obtaining a first syntax element representing whether an identification (ID) of the current layer is greater than 0,
obtaining a second syntax element indicating whether the current layer belongs to a first layer group when the ID of the current layer is greater than 0,
obtaining a third syntax element indicating whether the ID of the current layer is 1 or 2 when the current layer belongs to the first layer group, and
obtain ID information indicating the ID of the current layer when the ID of the current layer is greater than 0, and
wherein the ID information is binarized based on an exponential Golomb code with order 1.
4. The apparatus of claim 3 , wherein the ID of the current layer is determined as 3 when the current layer does not belong to the first layer group.