Method and apparatus for processing video signal
The present invention relates to a method and apparatus for processing a video signal, which can increase the accuracy of the motion vector prediction through motion vector scaling which takes a difference in the temporal distance between reference pictures into consideration. To this end, the present invention provides a video signal processing method and a video signal processing apparatus using the same, and the method comprises the steps of: scaling at least one neighboring partition motion vector for a motion vector prediction of the current partition; scaling the neighboring partition motion vector, which has been selected, when the reference picture of the neighboring partition motion vector is different from the reference picture of the current partition; acquiring a motion vector prediction value of the current partition using the scaled motion vector; and acquiring a motion vector of the current partition using the motion vector prediction value.
1. A method for decoding a bitstream for a video signal, the method comprising:
deriving at least one motion vector candidate from at least one neighboring block of a current block;
constructing a motion vector candidate group of the current block, the motion vector candidate group comprising a plurality of motion vector candidates including the derived at least one motion vector candidate;
obtaining a motion vector predictor of the current block from the constructed motion vector candidate group; and
decoding the current block based on the motion vector predictor,
wherein the deriving the at least one motion vector candidate includes:
selecting a motion vector of the at least one neighboring block as the at least one motion vector candidate when a first reference picture list is used for the current block, a second reference picture list different from the first reference picture list is used for the at least one neighboring block, and a reference picture of the current block in the first reference picture list has a same picture order count (POC) value as a reference picture of the at least one neighboring block in the second reference picture list.
2. The method of claim 1 , wherein the deriving the at least one motion vector candidate further includes:
selecting the motion vector of the at least one neighboring block as the at least one motion vector candidate when the first reference picture list is used for the at least one neighboring block and the current block and the reference picture of the current block in the first reference picture list has the same POC value as the reference picture of the at least one neighboring block in the first reference picture list.
3. The method of claim 1 , wherein the first reference picture list corresponds to a reference picture list 0 , and the second reference picture list corresponds to a reference picture list 1 .
4. The method of claim 1 , further comprising:
obtaining index information from the bitstream,
wherein a motion vector candidate specified by the index information from among the motion vector candidate group is assigned to the motion vector predictor of the current block.
5. The method of claim 1 , wherein the at least one neighboring block includes at least one of a bottom left neighboring block of the current block or a left neighboring block adjacent to the current block.
6. The method of claim 1 , wherein the at least one neighboring block includes at least one of a top right neighboring block of the current block, a top neighboring block of the current block, or a top left neighboring block adjacent to the current block.
7. The method of claim 1 , further comprising:
deriving a motion vector candidate from a co-located block of the current block, the co-located block being located in a position corresponding to the current block in a picture different from a picture including the current block,
wherein the motion vector candidate group further comprises the motion vector candidate derived from the co-located block.
8. The method of claim 1 , wherein the POC value represents a number assigned to a picture according to a temporal order of the picture.
9. An apparatus for decoding a bitstream for a video signal, the apparatus comprising:
a memory; and
a processor operatively connected to the memory and configured to:
derive at least one motion vector candidate from at least one neighboring block of a current block,
construct a motion vector candidate group of the current block, the motion vector candidate group comprising a plurality of motion vector candidates including the derived at least one motion vector candidate,
obtain a motion vector predictor of the current block from the constructed motion vector candidate group, and
decode the current block based on the motion vector predictor,
wherein the deriving the at least one motion vector candidate includes:
selecting a motion vector of the at least one neighboring block as the at least one motion vector candidate when a first reference picture list is used for the at least one neighboring block, a second reference picture list different from the first reference picture list is used for the current block, and a reference picture of the at least one neighboring block in the first reference picture list has a same picture order count (POC) value as a reference picture of the current block in the second reference picture list.
10. The apparatus of claim 9 , wherein the deriving the at least one motion vector candidate further includes:
selecting the motion vector of the at least one neighboring block as the at least one motion vector candidate when the first reference picture list is used for the at least one neighboring block and the current block and the reference picture of the at least one neighboring block in the first reference picture list has the same POC value as the reference picture of the current block in the first reference picture list.
11. The apparatus of claim 9 , wherein the first reference picture list corresponds to a reference picture list 0 , and the second reference picture list corresponds to a reference picture list 1 .
12. The apparatus of claim 9 , wherein the processor is further configured to obtain index information from the bitstream,
wherein a motion vector candidate specified by the index information from among the motion vector candidate group is assigned to the motion vector predictor of the current block.
13. The apparatus of claim 9 , wherein the at least one neighboring block includes at least one of a bottom left neighboring block of the current block or a left neighboring block adjacent to the current block.
14. The apparatus of claim 9 , wherein the at least one neighboring block includes at least one of a top right neighboring block of the current block, a top neighboring block of the current block, or a top left neighboring block adjacent to the current block.
15. The apparatus of claim 9 , wherein the processor is further configured to:
derive a motion vector candidate from a co-located block of the current block, the co-located block being located in a position corresponding to the current block in a picture different from a picture including the current block,
wherein the motion vector candidate group further comprises the motion vector candidate derived from the co-located block.
16. The apparatus of claim 9 , wherein the POC value represents a number assigned to a picture according to a temporal order of the picture.