Offset vector identification of temporal motion vector predictor
In one example, a method includes receiving, in a coded video bitstream and for a current prediction unit (PU) of a current picture of video data, a representation of an offset vector that identifies a block of a reference picture, wherein the offset vector is within a set of values that are not uniformly distributed. The example method further includes determining, based on the block of the reference picture identified by the offset vector, motion information for the current PU. The example method further includes reconstructing the current PU based on the determined motion information.
1. A method of decoding video data, the method comprising:
receiving, in a coded video bitstream and for a current prediction unit (PU) of a current picture of video data, a representation of an offset vector that represents a horizontal and a vertical displacement between the current PU and a block of a reference picture, wherein the offset vector displacements are within a set of values that are not uniformly distributed, and wherein the set of values is {−8, −4, −2, 0, 2, 4, 8};
determining, based on the block of the reference picture identified by the offset vector, motion information for the current PU; and
reconstructing a block of the current picture corresponding to the current PU based on the determined motion information.
2. The method of claim 1 , further comprising:
partitioning the PU into two or more sub-PUs;
determining, based on the block of the reference picture identified by the offset vector, respective motion information for each respective sub-PU of the sub-PUs; and
reconstructing blocks of the current picture respectively corresponding to each of the sub-PUs separately based on the motion information for each of the sub-PUs.
3. The method of claim 1 , further comprising:
receiving, in the coded video bitstream, an identification of the reference picture.
4. The method of claim 1 , further comprising:
determining, based on one or more existing merge candidates or motion information of one or more neighboring blocks of the current PU, an identification of the reference picture.
5. The method of claim 1 , wherein the received representation of the offset vector comprises a difference between a value of the offset vector and a value of an offset vector predictor for the current PU.
6. The method of claim 5 , further comprising:
determining, based on one or more spatial or temporal neighbors of the current PU, one or more offset vector predictors; and
determining the offset vector predictor for the current PU based on the one or more offset vector predictor.
7. The method of claim 1 , wherein values in the set of values are in units that are based on a smallest block size in the reference picture for which a motion vector may be stored, and wherein a distance between a value in the set of values and a next largest value in the set of values is greater than one unit.
8. The method of claim 1 , further comprising:
selecting, based on a picture order count (POC) difference between the current picture and the reference picture, the set of values from a plurality of sets of values.
9. A device for decoding video data, the device comprising:
a memory configured to store video data; and
one or more processors implemented in circuitry and configured to:
receive, in a coded video bitstream and for a current prediction unit (PU) of a current picture of the video data, a representation of an offset vector that represents a horizontal and a vertical displacement between the current PU and a block of a reference picture, wherein the offset vector displacements are within a set of values that are not uniformly distributed, and wherein the set of values is {−8, −4, −2, 0, 2, 4, 8};
determine, based on the block of the reference picture identified by the offset vector, motion information for the current PU; and
reconstruct a block of the video data corresponding to the current PU based on the determined motion information.
10. The device of claim 9 , wherein the one or more processors are further configured to:
partition the PU into two or more sub-PUs;
determine, based on the block of the reference picture identified by the offset vector, respective motion information for each respective sub-PU of the sub-PUs; and
reconstruct blocks of the current picture respectively corresponding to each of the sub-PUs separately based on the motion information for each of the sub-PUs.
11. The device of claim 9 , wherein the one or more processors are further configured to:
receive, in the coded video bitstream, an identification of the reference picture.
12. The device of claim 9 , wherein the one or more processors are further configured to:
determine, based on one or more existing merge candidates or motion information of one or more neighboring blocks of the current PU, an identification of the reference picture.
13. The device of claim 9 , wherein the received representation of the offset vector comprises a difference between a value of the offset vector and a value of an offset vector predictor for the current PU.
14. The device of claim 13 , wherein the one or more processors are further configured to:
determine, based on one or more spatial or temporal neighbors of the current PU, one or more offset vector predictors; and
determine the offset vector predictor for the current PU based on the one or more offset vector predictors.
15. The device of claim 9 , wherein values in the set of values are in units that are based on a smallest block size in the reference picture for which a motion vector may be stored, and wherein a distance between a value in the set of values and a next largest value in the set of values is greater than one unit.
16. The device of claim 9 , wherein the one or more processors are further configured to:
select, based on a picture order count (POC) difference between the current picture and the reference picture, the set of values from a plurality of sets of values.
17. The device of claim 9 , wherein the device is a wireless communication device, further comprising:
a receiver configured to receive the coded video bitstream; and
a display configured to display video data including the reconstructed block of video data.
18. The device of claim 17 , wherein the wireless communication device is a cellular telephone and the coded video bitstream is received by the receiver and modulated according to a cellular communication standard.
19. A non-transitory computer-readable storage medium storing instructions that, when executed, cause one or more processors of a video decoder to:
receive, in a coded video bitstream and for a current prediction unit (PU) of a current picture of video data, a representation of an offset vector that represents a horizontal and a vertical displacement between the current PU and a block of a reference picture, wherein the offset vector displacements are within a set of values that are not uniformly distributed, and wherein the set of values is {−8, −4, −2, 0, 2, 4, 8};
determine, based on the block of the reference picture identified by the offset vector, motion information for the current PU; and
reconstruct a block of the video data corresponding to the current PU based on the determined motion information.