Split based motion vector operation reduction
A reduced merge candidate signaling method is provided. When building a merge candidate list for a prediction unit (PU) of a block of pixels, a video codec skips or partially skips the construction of some sub-PU merge candidates. The video codec then performs simplified pruning operations on the merge candidate list based on the skipped or partially constructed sub-PU merge candidates. The pruned candidate list is then used to select a merge candidate to encode or decode the block of pixels.
1. A method comprising:
receiving a block of pixels that comprises a prediction unit (PU);
generating, for the PU, a merge candidate list comprising one or more merge candidates;
partially constructing a sub-PU merge candidate by identifying or generating a first set of data for the sub-PU merge candidate;
adding the partially constructed sub-PU merge candidate to the merge candidate list;
identifying a redundant merge candidate by comparing the first set of data for the partially constructed sub-PU merge candidate with a corresponding set of data for another merge candidate in the merge candidate list; and
removing the identified redundant merge candidate from the merge candidate list.
2. The method of claim 1 , further comprising:
completing the sub-PU merge candidate by generating a second set of data based on the first set of data;
selecting a merge candidate from the merge candidate list that includes the completed sub-PU merge candidate; and
encoding the block of pixels by using the selected merge candidate.
3. The method of claim 1 , further comprising:
selecting a merge candidate from the merge candidate list; and
when the selected merge candidate is the sub-PU merge candidate, completing the sub-PU merge candidate by generating a second set of data based on the first set of data and decoding the block of pixels by using the completed sub-PU merge candidate.
4. The method of claim 3 , wherein:
the first set of data comprises motion information for a first subset of sub-PUs in the PU, and
the second set of data comprises motion information for a second subset of sub-PUs in the PU.
5. The method of claim 1 , wherein the sub-PU merge candidate is a first sub-PU merge candidate and the other merge candidate is a second sub-PU merge candidate, and wherein identifying the redundant merge candidate comprises comparing the motion information of the first subset of sub-PUs of the first sub-PU merge candidate with motion information of a corresponding subset of sub-PUs of the second sub-PU merge candidate.
6. The method of claim 1 , wherein the other merge candidate is a non-sub-PU merge candidate, and wherein identifying the redundant merge candidate comprises comparing the motion information of a subset of the sub-PU of the sub-PU merge candidate with motion information of the non-sub-PU merge candidate.
7. The method of claim 1 , wherein the sub-PU merge candidate is a first sub-PU merge candidate and the other merge candidate is a second sub-PU merge candidate, and wherein identifying the redundant merge candidate comprises comparing an initial motion vector of the first sub-PU merge candidate with an initial motion vector of the second sub-PU merge candidate.
8. The method of claim 1 , wherein the sub-PU merge candidate is a first sub-PU merge candidate and the other merge candidate is a second sub-PU merge candidate, and wherein identifying the redundant merge candidate comprises comparing a neighboring motion vector of the first sub-PU merge candidate with a neighboring motion vector of the second sub-PU merge candidate.
9. The method of claim 1 , wherein the partially constructing of the sub-PU merge candidate comprises generating the sub-PU merge candidate by determining initial motion vectors for different sub-PUs, and wherein the initial motion vectors for each sub-PU is used to identify motion information in a collocated picture.
10. The method of claim 1 , wherein the partially constructing of the sub-PU merge candidate comprises generating the sub-PU merge candidate by determining an average motion vector for each sub-PU based on the sub-PU's two spatial neighbors and one temporal neighbor.
11. An electronic apparatus comprising:
a video encoder circuit capable of:
receiving a block of pixels that comprises a prediction unit (PU);
generating, for the PU, a merge candidate list comprising one or more merge candidates;
partially constructing a sub-PU merge candidate by identifying or generating a first set of data for the sub-PU merge candidate;
adding the partially constructed sub-PU merge candidate to the merge candidate list;
identifying a redundant merge candidate by comparing the first set of data for the partially constructed sub-PU merge candidate with a corresponding set of data for another merge candidate in the merge candidate list;
removing the identified redundant merge candidate from the merge candidate list;
completing the sub-PU merge candidate by generating a second set of data based on the first set of data;
selecting a merge candidate from the merge candidate list that includes the completed sub-PU merge candidate; and
encoding the block of pixels by using the selected merge candidate.
12. The electronic apparatus of claim 11 , wherein:
the first set of data comprises motion information for a first subset of sub-PUs in the PU, and
the second set of data comprises motion information for a second subset of sub-PUs in the PU.
13. The electronic apparatus of claim 11 , wherein the sub-PU merge candidate is a first sub-PU merge candidate and the other merge candidate is a second sub-PU merge candidate, and wherein, in identifying the redundant merge candidate, the video encoder circuit compares an initial motion vector of the first sub-PU merge candidate with an initial motion vector of the second sub-PU merge candidate, wherein the first sub-PU merge candidate is generated by determining initial motion vectors for different sub-PUs, wherein the initial motion vectors for each sub-PU is used to identify motion information in a collocated picture.
14. An electronic apparatus comprising:
a video decoder circuit capable of:
receiving a block of pixels that comprises a prediction unit (PU);
generating, for the PU, a merge candidate list comprising one or more merge candidates;
partially constructing a sub-PU merge candidate by identifying or generating a first set of data for the sub-PU merge candidate;
adding the partially constructed sub-PU merge candidate to the merge candidate list;
selecting a merge candidate from the merge candidate list; and
when the selected merge candidate is the sub-PU merge candidate, completing the sub-PU merge candidate by generating a second set of data based on the first set of data and decoding the block of pixels by using the completed sub-PU merge candidate.
15. The electronic apparatus of claim 14 , wherein the video decoder circuit is further capable of receiving a merge index and using the received merge index to select the merge candidate from the merge candidate list.
16. The electronic apparatus of claim 14 , wherein, when the selected merge candidate is not the sub-PU merge candidate, the second set of data is not generated.
17. The electronic apparatus of claim 14 , wherein:
the first set of data comprises motion information for a first subset of sub-PUs in the PU, and
the second set of data comprises motion information for a second subset of sub-PUs in the PU.
18. The electronic apparatus of claim 14 , wherein the video decoder circuit is further capable of:
identifying a redundant merge candidate by comparing the first set of data for the partially constructed sub-PU merge candidate with a corresponding set of data for a different merge candidate in the merge candidate list; and
removing the identified redundant merge candidate from the merge candidate list.
19. The electronic apparatus of claim 18 , wherein the sub-PU merge candidate is a first sub-PU merge candidate and the other merge candidate is a second sub-PU merge candidate, and wherein, in identifying the redundant merge candidate, the video decoder circuit compares an initial motion vector of the first sub-PU merge candidate with an initial motion vector of the second sub-PU merge candidate.
20. An electronic apparatus comprising:
a video decoder circuit capable of:
receiving a block of pixels that comprises a prediction unit (PU);
generating, for the PU, a merge candidate list comprising one or more merge candidates that includes a sub-PU merge candidate that is incomplete;
selecting a merge candidate from the merge candidate list; and
when the selected merge candidate is the sub-PU merge candidate, completing the sub-PU merge candidate and decoding the block of pixels by using the completed sub-PU merge candidate.