Method of predicting motion vectors in video codec in which multiple references are allowed, and motion vector encoding/decoding apparatus using the same
Initial value is selected when motion estimation is performed using predicted motion vector in video codec in which multiple references are allowed, and coding amount of motion vectors is reduced using predicted motion vector. Motion vector encoding apparatus includes predicted motion vector generator that generates adjacent motion vectors of current block with respect to each of reference pictures and generates each predicted motion vector of the current block from the generated adjacent motion vectors, motion estimator that determines final motion vector of the current block and final reference picture corresponding to the final motion vector with regard to search regions of the reference pictures, differential unit that obtains difference between the final motion vector of the current block and final predicted motion vector corresponding to the determined final reference picture among the predicted motion vectors, and unit for encoding information about the final reference picture and the difference.
1. A decoding method of a decoding device, comprising:
obtaining, by the decoding device, a motion vector difference for a current block in a current picture from an input bitstream;
obtaining, by the decoding device, a motion vector of a neighboring block of the current block, wherein the neighboring block is in the current picture and wherein the motion vector of the neighboring block is used to decode the neighboring block according to a reference picture of the neighboring block;
interpolating, by the decoding device, the motion vector of the neighboring block of the current block based on a distance between the reference picture of the neighboring block and the current picture and a distance between a reference picture of the current block and the current picture to generate an interpolated motion vector, wherein the refrence picture of the neighboring block is different from the reference picture of the current block;
predicting, by the decoding device, a motion vector of the current block based on the interpolated motion vector to generate a predicted motion vector; and
adding, by the decoding device, the predicted motion vector and the motion vector difference to generate the motion vector of the current block.
2. The decoding method of claim 1 , further comprising:
performing, by the decoding device, a motion compensating by using the motion vector of the current block to generate a motion compensated block of the current block; and
adding, by the decoding device, a residual block of the current block and the motion compensated block of the current block to reconstruct the current block.
3. The decoding method of claim 1 , wherein the neighboring block is formed in a rectangular shape by asymmetric partition.
4. The decoding method of claim 1 , wherein interpolating the motion vector of the neighboring block comprises:
interpolating the motion vector of the neighboring block based on the distance between the reference picture of the neighboring block and the current picture and the distance between the reference picture of the current block and the current picture to generate the interpolated motion vector, when the distance between the reference picture of the neighboring block and the current picture is equal to or greater than the distance between the reference picture of the current block and the current picture.
5. The decoding method of claim 1 , wherein the neighboring block is one of a left block, an upper block, and a right upper block of the current block.
6. The decoding method of claim 1 , wherein predicting the motion vector of the current block comprises:
selecting one among a plurality of interpolated motion vectors including the interpolated motion vector as the predicted motion vector.
7. The decoding method of claim 6 , wherein selecting one among the plurality of interpolated motion vectors comprises:
selecting a median value among the plurality of the interpolated motion vectors including the interpolated motion vector as the predicted motion vector.
8. A decoding device, comprising:
a decoder configured to obtain a motion vector difference for a current block from an input bitstream;
a predicted motion vector generator configured to:
interpolate a motion vector of a neighboring block of the current block based on a distance between a reference picture of the neighboring block and a current picture and a distance between a reference picture of the current block and the current picture to generate an interpolated motion vector, and
predict a motion vector of the current block based on the interpolated motion vector to generate a predicted motion vector,
wherein the neighboring block and the current block are in the current picture, the motion vector of the neighboring block is used to decode the neighboring block according to the reference picture of the neighboring block, and the reference picture of the neighboring block is different from the reference picture of the current block; and
a first adder configured to add the predicted motion vector and the motion vector difference to generate the motion vector of the current block.
9. The decoding device of claim 8 , further comprising:
a motion compensator configured to perform a motion compensating by using the motion vector of the current block to generate a motion compensated block of the current block; and
a second adder configured to add a residual block of the current block and the motion compensated block of the current block to reconstruct the current block.
10. The decoding device of claim 8 , wherein the neighboring block is formed in a rectangular shape by asymmetric partition.
11. The decoding device of claim 8 , wherein the predicted motion vector generator interpolates the motion vector of the neighboring block based on the distance between the reference picture of the neighboring block and the current picture and the distance between the reference picture of the current block and the current picture to generate the interpolated motion vector, when the distance between the reference picture of the neighboring block and the current picture is equal to or greater than the distance between the reference picture of the current block and the current picture.
12. The decoding device of claim 8 , wherein the neighboring block is one of a left block, an upper block, and a right upper block of the current block.
13. The decoding device of claim 9 , wherein the predicted motion vector generator is configured to select one among a plurality of interpolated motion vectors including the interpolated motion vector as the predicted motion vector.
14. The decoding device of claim 13 , wherein the predicted motion vector generator is configured to select a median value among the plurality of the interpolated motion vectors including the interpolated motion vector as the predicted motion vector.
15. An encoding method of an encoding device, comprising:
obtaining, by the encoding device, a motion vector of a neighboring block of a current block, wherein the neighboring block and the current block are in a current picture and the motion vector of the neighboring block is used to encode the neighboring block according to a reference picture of the neighboring block;
interpolating, by the encoding device, the motion vector of the neighboring block of the current block based on a distance between the reference picture of the neighboring block and the current picture and a distance between a reference picture of the current block and the current picture to generate an interpolated motion vector, wherein the reference picture of the neighboring block is different from the reference picture of the current block;
predicting, by the encoding device, a motion vector of the current block based on the interpolated motion vector to generate a predicted motion vector;
generating, by the encoding device, the motion vector of the current block; and
encoding, by the encoding device, a difference between the motion vector of the current block and the predicted motion vector.
16. The encoding method of claim 15 , further comprising:
generating, by the encoding device, a motion compensated block by using the motion vector of the current block; and
encoding, by the encoding device, a difference between the current block and the motion compensated block.
17. The encoding method of claim 16 , wherein encoding the difference between the current block and the motion compensated block comprises:
transforming the difference between the current block and the motion compensated block into transform coefficients of a frequency domain;
quantizing the transform coefficients to generate quantized transform coefficients; and
encoding the quantized transform coefficients.
18. The encoding method of claim 17 , further comprising:
generating, by the encoding device, a bitstream including the difference between the motion vector of the current block and the predicted motion vector, and the quantized transform coefficients.
19. The encoding method of claim 15 , wherein the neighboring block is one of a left block, an upper block, and a right upper block of the current block.
20. The encoding method of claim 15 , wherein the neighboring block is formed in a rectangular shape by asymmetric partition.