Hierarchy of motion prediction video blocks

1. A method of decoding video data according to a merge mode, the method comprising:

obtaining an index value for a current video block coded in the merge mode;

generating a set of candidate predictive blocks for the merge mode based on spatial and temporal neighbors to the current video block;

limiting the set of generated candidate predictive blocks for the merge mode to a subset of generated candidate predictive blocks for the merge mode, wherein the subset of generated candidate predictive blocks for the merge mode is limited to be smaller than the set of generated candidate predictive blocks for the merge mode;

selecting a predictive video block from the subset of generated candidate predictive blocks for the merge mode based on the index value; and

generating motion information for the current video block according to the merge mode based on motion information of the predictive video block, wherein generating the motion information for the current video block includes inheriting motion information from the predictive video block.

2. The method of claim 1 , wherein the subset of generated candidate predictive blocks includes three candidate predictive blocks.

3. The method of claim 2 , wherein the set of generated candidate predictive blocks includes: an adjacent left video block to the current video block, an adjacent upper video block to the current video block, an adjacent upper-right video block to the current video block, an adjacent lower-left video block to the current video block, and an adjacent temporal video block to the current video block.

4. The method of claim 1 , wherein inheriting the motion information includes inheriting a motion vector and a reference frame index from the predictive video block.

5. A device for decoding video data according to a merge mode, the device comprising:

a memory configured to store video data; and

a video decoder configured to communicate with the memory and to:

obtain an index value for the current video block coded in the merge mode;

generate a set of candidate predictive blocks for the merge mode based on spatial and temporal neighbors to the current video block;

limit the set of generated candidate predictive blocks for the merge mode to a subset of generated candidate predictive blocks for the merge mode, wherein the subset of generated candidate predictive blocks for the merge mode is limited to be smaller than the set of generated candidate predictive blocks for the merge mode;

select a predictive video block from the subset of generated candidate predictive blocks for the merge mode based on the index value; and

generate motion information for the current video block according to the merge mode based on motion information of the predictive video block, wherein generating the motion information for the current video block includes inheriting a motion vector from the predictive video block.

6. The device of claim 5 , wherein the subset of generated candidate predictive blocks includes three candidate predictive blocks.

7. The device of claim 6 , wherein the set of generated candidate predictive blocks includes: an adjacent left video block to the current video block, an adjacent upper video block to the current video block, an adjacent upper-right video block to the current video block, an adjacent lower-left video block to the current video block, and an adjacent temporal video block to the current video block.

8. The device of claim 1 , wherein configured to inherit the motion information includes configured to inherit a motion vector and a reference frame index from the predictive video block.

9. The device of claim 5 , wherein the device comprises at least one of:

an integrated circuit;

a microprocessor; and

a wireless communication device that includes the video decoder.

10. A device for decoding video data according to a merge mode, the device comprising:

means for storing video data;

means for obtaining an index value for a current video block coded in the merge mode;

means for generating a set of candidate predictive blocks for the merge mode based on spatial and temporal neighbors to the current video block;

means for limiting the set of generated candidate predictive blocks for the merge mode to a subset of generated candidate predictive blocks for the merge mode, wherein the subset of generated candidate predictive blocks for the merge mode is limited to be smaller than the set of generated candidate predictive blocks for the merge mode;

means for selecting a predictive video block from the subset of generated candidate predictive blocks for the merge mode based on the index value; and

means for generating motion information for the current video block according to the merge mode based on motion information of the predictive video block, wherein the means for generating the motion information for the current video block includes means for inheriting motion information from the predictive video block.

11. The device of claim 10 , wherein the subset of generated candidate predictive blocks includes three candidate predictive blocks.

12. The device of claim 11 , wherein the set of generated candidate predictive blocks includes: an adjacent left video block to the current video block, an adjacent upper video block to the current video block, an adjacent upper-right video block to the current video block, an adjacent lower-left video block to the current video block, and an adjacent temporal video block to the current video block.

13. The device of claim 10 , wherein means for inheriting the motion information includes means for inheriting a motion vector and a reference frame index from the predictive video block.

14. A computer program product comprising a non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause a processor of a device for decoding video data according to a merge mode to:

obtain an index value for a current video block coded in the merge mode;

generate a set of candidate predictive blocks for the merge mode based on spatial and temporal neighbors to the current video block;

limit the set of generated candidate predictive blocks for the merge mode to a subset of generated candidate predictive blocks for the merge mode, wherein the subset of generated candidate predictive blocks for the merge mode is limited to be smaller than the set of generated candidate predictive blocks for the merge mode;

select a predictive video block from the subset of generated candidate predictive blocks for the merge mode based on the index value; and

generate motion information for the current video block according to the merge mode based on motion information of the predictive video block, wherein generating the motion information for the current video block includes inheriting a motion vector from the predictive video block.

15. The computer program product of claim 14 , wherein the subset of generated candidate predictive blocks includes three candidate predictive blocks.

16. The computer program product of claim 15 , wherein the set of generated candidate predictive blocks includes: an adjacent left video block to the current video block, an adjacent upper video block to the current video block, an adjacent upper-right video block to the current video block, an adjacent lower-left video block to the current video block, and an adjacent temporal video block to the current video block.

17. The computer program product of claim 14 , wherein the instructions that, when executed, cause a processor to inherit the motion information includes instructions that, when executed, cause a processor to inherit a motion vector and a reference frame index from the predictive video block.

18. A method of encoding video data according to a merge mode, the method comprising:

obtaining a motion vector for a current video block;

generating a set of candidate predictive blocks for the merge mode based on spatial and temporal neighbors to the current video block;

limiting the set of generated candidate predictive blocks for the merge mode to a subset of generated candidate predictive blocks for the merge mode, wherein the subset of generated candidate predictive blocks for the merge mode is limited to be smaller than the set of generated candidate predictive blocks for the merge mode;

selecting a predictive video block from the subset of generated candidate predictive blocks for the merge mode based on the motion vector; and

generating an index value identifying a selected predictive video block according to the merge mode.

19. The method of claim 18 , wherein the subset of generated candidate predictive blocks includes three candidate predictive blocks.

20. The method of claim 19 , wherein the set of generated candidate predictive blocks includes: an adjacent left video block to the current video block, an adjacent upper video block to the current video block, an adjacent upper-right video block to the current video block, an adjacent lower-left video block to the current video block, and an adjacent temporal video block to the current video block.

21. A device for encoding video data, the device comprising:

a memory configured to store video data; and

a video encoder configured to communicate with the memory and to:

obtain a motion vector for a current video block;

generate a set of candidate predictive blocks for the merge mode based on spatial and temporal neighbors to the current video block;

limit the set of generated candidate predictive blocks for the merge mode to a subset of generated candidate predictive blocks for the merge mode, wherein the subset of generated candidate predictive blocks for the merge mode is limited to be smaller than the set of generated candidate predictive blocks for the merge mode;

select a predictive video block from the subset of generated candidate predictive blocks for the merge mode based on the motion vector; and

generate an index value identifying a selected predictive video block according to the merge mode.

22. The device of claim 21 , wherein the subset of generated candidate predictive blocks includes three candidate predictive blocks.

23. The device of claim 22 , wherein the set of generated candidate predictive blocks includes: an adjacent left video block to the current video block, an adjacent upper video block to the current video block, an adjacent upper-right video block to the current video block, an adjacent lower-left video block to the current video block, and an adjacent temporal video block to the current video block.

24. The device of claim 21 , wherein the device comprises at least one of:

an integrated circuit;

a microprocessor; and

a wireless communication device that includes the video decoder.

25. A device for encoding video data according to a merge mode, the device comprising:

means for storing video data;

means for obtaining a motion vector for a current video block;

means for generating a set of candidate predictive blocks based on spatial and temporal neighbors to the current video block;

means for limiting the set of generated candidate predictive blocks for the merge mode to a subset of generated candidate predictive blocks for the merge mode, wherein the subset of generated candidate predictive blocks for the merge mode is limited to be smaller than the set of generated candidate predictive blocks for the merge mode;

means for selecting a predictive video block from the subset of generated candidate predictive blocks for the merge mode based on the motion vector; and

means for generating an index value identifying a selected predictive video block according to the merge mode.

26. The device of claim 25 , wherein the subset of generated candidate predictive blocks includes three candidate predictive blocks.

27. The device of claim 26 , wherein the set of generated candidate predictive blocks includes: an adjacent left video block to the current video block, an adjacent upper video block to the current video block, an adjacent upper-right video block to the current video block, an adjacent lower-left video block to the current video block, and an adjacent temporal video block to the current video block.

28. A computer program product comprising a non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause a processor of a device for encoding video data to:

obtain a motion vector for a current video block;

generate a set of candidate predictive blocks for the merge mode based on spatial and temporal neighbors to the current video block;

limit the set of generated candidate predictive blocks for the merge mode to a subset of generated candidate predictive blocks for the merge mode, wherein the subset of generated candidate predictive blocks for the merge mode is limited to be smaller than the set of generated candidate predictive blocks for the merge mode;

select a predictive video block from the subset of generated candidate predictive blocks for the merge mode based on the motion vector; and

generate an index value identifying a selected predictive video block according to the merge mode.

29. The computer program product of claim 28 , wherein the subset of generated candidate predictive blocks includes three candidate predictive blocks.

30. The computer program product of claim 29 , wherein the set of generated candidate predictive blocks includes: an adjacent left video block to the current video block, an adjacent upper video block to the current video block, an adjacent upper-right video block to the current video block, an adjacent lower-left video block to the current video block, and an adjacent temporal video block to the current video block.

31. The method of claim 1 , wherein the set of generated candidate predictive blocks comprises five candidate predictive blocks, and wherein the subset of generated candidate predictive blocks comprises the top three candidate predictive blocks of the five candidate predictive blocks in the set of generated candidate predictive blocks.

32. The device of claim 5 , wherein the set of generated candidate predictive blocks comprises five candidate predictive blocks, and wherein the subset of generated candidate predictive blocks comprises the top three candidate predictive blocks of the five candidate predictive blocks in the set of generated candidate predictive blocks.

33. The device of claim 10 , wherein the set of generated candidate predictive blocks comprises five candidate predictive blocks, and wherein the subset of generated candidate predictive blocks comprises the top three candidate predictive blocks of the five candidate predictive blocks in the set of generated candidate predictive blocks.

34. The computer program product of claim 14 , wherein the set of generated candidate predictive blocks comprises five candidate predictive blocks, and wherein the subset of generated candidate predictive blocks comprises the top three candidate predictive blocks of the five candidate predictive blocks in the set of generated candidate predictive blocks.

35. The method of claim 18 , wherein the set of generated candidate predictive blocks comprises five candidate predictive blocks, and wherein the subset of generated candidate predictive blocks comprises the top three candidate predictive blocks of the five candidate predictive blocks in the set of generated candidate predictive blocks.

36. The device of claim 21 , wherein the set of generated candidate predictive blocks comprises five candidate predictive blocks, and wherein the subset of generated candidate predictive blocks comprises the top three candidate predictive blocks of the five candidate predictive blocks in the set of generated candidate predictive blocks.

37. The device of claim 25 , wherein the set of generated candidate predictive blocks comprises five candidate predictive blocks, and wherein the subset of generated candidate predictive blocks comprises the top three candidate predictive blocks of the five candidate predictive blocks in the set of generated candidate predictive blocks.

38. The computer program product of claim 28 , wherein the set of generated candidate predictive blocks comprises five candidate predictive blocks, and wherein the subset of generated candidate predictive blocks comprises the top three candidate predictive blocks of the five candidate predictive blocks in the set of generated candidate predictive blocks.