MMVD and SMVD combination with motion and prediction models
The general aspects extend motion modes, such as merge with motion vector difference, and symmetrical motion vector difference, to motion models beyond a simple translational model, for example in combination with merge and alternative temporal motion vector prediction modes. Embodiments extend the use of MMVD and SMVD motion vector coding tools to all the motion model derivation methods and temporal prediction methods that are supported in proposed video standards, so as to increase the overall compression performance. Particular embodiments describe combining MMVD or SMVD with the affine motion model, the ATMVP motion model, the planar motion model, the regressive motion field, the triangle-partition-based motion model, the GBI temporal prediction method, the LIC temporal prediction method and the Multi-hypothesis prediction method.
1. A method, comprising:
indicating use of a merge mode with motion vector difference through syntax in a video bitstream;
indicating use of a bi-prediction mode through syntax in the video bitstream; and, responsive to the syntaxes:
encoding a first set of merge mode with motion vector difference indices for a first reference picture;
obtaining a second set of merge mode with motion vector difference indices wherein a direction index for said second set is obtained based on a direction index encoded for said first set;
encoding the second set without said direction index; and
encoding a block of a current picture using indices of said first and second sets.
2. An apparatus, comprising:
a processor, configured to:
indicate use of a merge mode with motion vector difference through syntax in a video bitstream;
indicate use of a bi-prediction mode through syntax in the video bitstream; and, responsive to the syntaxes:
encode a first set of merge mode with motion vector difference indices for a first reference picture;
obtain a second set of merge mode with motion vector difference indices wherein a direction index for said second set is obtained based on a direction index encoded for said first set;
encode the second set without said direction index; and
encode a block of a current picture using indices of said first and second sets.
3. A method, comprising:
parsing a video bitstream for syntax indicative of use of a merge mode with motion vector difference;
parsing the video bitstream for syntax indicative of use of a bi-prediction mode; and, responsive to at least one of said syntaxes:
decoding a first set of merge mode with motion vector difference indices for a first reference picture;
obtaining a second set of merge mode with motion vector difference indices for a second reference picture, wherein a direction index for said second set is obtained based on a direction index decoded for said first set; and
decoding a block of a current picture using indices of said first and second sets.
4. An apparatus, comprising:
a processor, configured to:
parse a video bitstream for syntax indicative of use of a merge mode with motion vector difference;
parse the video bitstream for syntax indicative of use of a bi-prediction mode; and, responsive to at least one of said syntaxes:
decode a first set of merge mode with motion vector difference indices for a first reference picture;
obtain a second set of merge mode with motion vector difference indices for a second reference picture, wherein a direction index for said second set is obtained based on a direction index decoded for said first set; and
decode a block of a current picture using indices of said first and second sets.
5. A device comprising:
the apparatus of claim 4 ; and
at least one of (i) an antenna configured to receive a signal, the signal including the block of the current picture, (ii) a band limiter configured to limit the received signal to a band of frequencies that includes the block of the current picture, and (iii) a display configured to display an output representative of the block of the current picture.
6. A non-transitory computer readable medium containing data content generated according to the method of claim 1 , for playback using a processor.
7. A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of claim 3 .
8. The method of claim 1 , wherein encoding the second set comprises encoding a distance index for said second set.
9. The method of claim 1 , wherein in the case where said first reference picture and a second reference picture are located at a same temporal side with respect to the current picture, said direction index for said second set is equal to said direction index encoded for said first set and wherein in the case where said first and second reference pictures are located at different temporal sides with respect to the current picture, said direction index for said second set is equal to an opposite of said direction index encoded for said first set.
10. The method of claim 1 , wherein encoding the second set comprises encoding a distance index for said second set, said distance index for said second set being representative of a differential distance with respect to a distance represented by a distance index encoded for said first set.
11. The method of claim 8 , wherein the distance index for said first set being representative of a distance in a set of N distances, said distance index for said second set is representative of a distance in a subset of said set of N distances, N being an integer.
12. The method of claim 3 , wherein obtaining the second set of merge mode with motion vector difference indices for the second reference picture comprises decoding a distance index for said second set.
13. The method of claim 3 , wherein in the case where said first and second reference pictures are located at a same temporal side with respect to the current picture, said direction index for said second set is equal to said direction index decoded for said first set and wherein in the case where said first and second reference pictures are located at different temporal sides with respect to the current picture, said direction index for said second set is equal to an opposite of said direction index decoded for said first set.
14. The method of claim 3 , wherein obtaining the second set of merge mode with motion vector difference indices for the second reference picture comprises decoding a distance index for said second set, said distance index for said second set being representative of a differential distance with respect to a distance represented by a distance index decoded for said first set.
15. The method of claim 12 , wherein the distance index for said first set being representative of a distance in a set of N distances, said distance index for said second set is representative of a distance in a subset of said set of N distances, N being an integer.
16. The apparatus of claim 2 , wherein encoding the second set comprises encoding a distance index for said second set.
17. The apparatus of claim 2 , wherein in the case where said first reference picture and a second reference picture are located at a same temporal side with respect to the current picture, said direction index for said second set is equal to said direction index encoded for said first set and wherein in the case where said first and second reference pictures are located at different temporal sides with respect to the current picture, said direction index for said second set is equal to an opposite of said direction index encoded for said first set.
18. The apparatus of claim 2 , wherein encoding the second set comprises encoding a distance index for said second set, said distance index for said second set being representative of a differential distance with respect to a distance represented by a distance index encoded for said first set.
19. The apparatus of claim 16 , wherein the distance index for said first set being representative of a distance in a set of N distances, said distance index for said second set is representative of a distance in a subset of said set of N distances, N being an integer.
20. The apparatus of claim 4 , wherein obtaining the second set of merge mode with motion vector difference indices for the second reference picture comprises decoding a distance index for said second set.
21. The apparatus of claim 4 , wherein in the case where said first and second reference pictures are located at a same temporal side with respect to the current picture, said direction index for said second set is equal to said direction index decoded for said first set and wherein in the case where said first and second reference pictures are located at different temporal sides with respect to the current picture, said direction index for said second set is equal to an opposite of said direction index decoded for said first set.
22. The apparatus of claim 4 , wherein obtaining the second set of merge mode with motion vector difference indices for the second reference picture comprises decoding a distance index for said second set, said distance index for said second set being representative of a differential distance with respect to a distance represented by a distance index decoded for said first set.
23. The apparatus of claim 20 , wherein the distance index for said first set being representative of a distance in a set of N distances, said distance index for said second set is representative of a distance in a subset of said set of N distances, N being an integer.