Subblock merge candidates in triangle merge mode
Sub-block merge motion field is combined with triangle partitioning and geometric partitioning modes to further give coding and decoding schemes flexibility. In at least one embodiment, a flag is used to signal if sub-block merge candidates are used in place of regular merge candidates. In another embodiment, regular merge candidates are replaced by sub-block merge candidates. In another embodiment, at least one motion field is stored. In another embodiment, all sub-block merge candidates or only sub-block temporal motion vector predictors or only affine predictors are considered.
1. A method, comprising:
obtaining unidirectional triangle candidates from a merge list for encoding a video block;
extracting portions of said unidirectional triangle candidates;
obtaining triangle merge candidates from a sub-block merge list of candidates, wherein the sub-block merge list in triangle partition mode is restricted based on dimensions of the video block;
extracting unidirectional seeds portion of said triangle merge candidates;
performing motion compensation on said video block using said portions of the unidirectional triangle candidates and said triangle merge candidates;
weighting the motion compensated video block;
signaling whether a sub-block or regular list of candidates was used for said motion compensated results; and
encoding the weighted motion compensated video block.
2. An apparatus, comprising:
a processor, configured to:
obtain unidirectional triangle candidates from a merge list for encoding a video block, wherein the merge list in triangle partition mode is restricted based on dimensions of the video block;
extract portions of said unidirectional triangle candidates;
obtain triangle merge candidates from a sub-block merge list of candidates;
extract unidirectional seeds portion of said triangle merge candidates;
perform motion compensation on said video block using said portions of the unidirectional triangle candidates and said triangle merge candidates;
weight the motion compensated video block;
signal whether a sub-block or regular list of candidates was used for said motion compensated results; and
encode the weighted motion compensated video block.
3. A method, comprising:
parsing a video bitstream to determine whether unidirectional triangle candidates are selected from a sub-block merge list or in a regular merge list;
obtaining unidirectional triangle candidates from either a sub-block merge list or a regular merge list for decoding a video block, wherein the sub-block merge list in triangle partition mode is restricted based on dimensions of the video block;
extracting portions of said unidirectional triangle candidates;
performing motion compensation on said video block using said portions of the unidirectional triangle candidates;
weighting the motion compensated video block; and
decoding the weighted motion compensated video block.
4. An apparatus, comprising:
a processor, configured to:
parse a video bitstream to determine whether unidirectional triangle candidates are selected from a sub-block merge list or in a regular merge list;
obtain unidirectional triangle candidates from either a sub-block merge list or a regular merge list for decoding a video block, wherein the sub-block merge list in triangle partition mode is restricted based on dimensions of the video block;
extract portions of said unidirectional triangle candidates;
perform motion compensation on said video block using said portions of the unidirectional triangle candidates;
weight the motion compensated video block; and
decode the weighted motion compensated video block.
5. The method of claim 1 , wherein said candidates comprise a sub-block temporal motion vector predictor, an inherited candidate, and a constructed affine model candidate.
6. The method of claim 1 , wherein usage of a sub-block merge list is restricted based on dimensions of a coding unit containing the video block, size of the coding unit, or coding unit area.
7. The apparatus of claim 2 , wherein if affine model candidates are only considered during unidirectional triangle list construction, sub-block merge list usage is restricted to coding units having at least an affine neighboring coding unit.
8. The apparatus of claim 2 , wherein a unidirectional triangle candidate is replaced by a sub-block candidate and one sub-block partition is combined with a regular partition.
9. The apparatus of claim 2 , further comprising storing a 4×4 motion field.
10. The method of claim 1 , wherein when candidates address a same reference picture list, 4×4 sub-blocks of a diagonal store a unidirectional motion field of a bottom candidate when both candidates are from a same merge list, and store regular unidirectional motion field when candidates are from different merge lists.
11. The apparatus of claim 2 , further comprising storing affine control point motion vectors associated with a triangular partition when a candidate is from a sub-block merge list and is affine.
12. A device comprising:
an apparatus according to claim 1 ; and
at least one of (i) an antenna configured to receive a signal, the signal including the video block, (ii) a band limiter configured to limit the received signal to a band of frequencies that includes the video block, and (iii) a display configured to display an output representative of a video block.
13. A non-transitory computer readable medium containing data content generated according to the method of claim 1 , for playback using a processor.
14. A non-transitory computer readable medium containing data content comprising instructions for performing the method of claim 3 .
15. 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 1 .
16. The method of claim 3 , wherein said candidates comprise a sub-block temporal motion vector predictor, an inherited candidate, and a constructed affine model candidate.
17. The method of claim 3 , wherein usage of a sub-block merge list is restricted based on dimensions of a coding unit containing the video block, size of the coding unit, or coding unit area.
18. The method of claim 3 , wherein if affine model candidates are only considered during unidirectional triangle list construction, sub-block merge list usage is restricted to coding units having at least an affine neighboring coding unit.
19. The apparatus of claim 4 , wherein a unidirectional triangle candidate is replaced by a sub-block candidate and one sub-block partition is combined with a regular partition.
20. The apparatus of claim 4 , further comprising storing a 4×4 motion field.