Method and apparatus for simplified motion vector predictor derivation

1. A method of deriving a motion vector predictor (MVP) candidate set for motion vector coding of a block, the method comprising:

determining, by circuitry of an apparatus, a redundancy-removed spatial-temporal MVP candidate set, wherein the redundancy-removed spatial-temporal MVP candidate set is derived from a spatial-temporal MVP candidate set by removing any redundant spatial MVP candidate; wherein the spatial-temporal MVP candidate set comprises a top spatial MVP candidate, a left spatial MVP candidate and one temporal MVP candidate;

checking whether a number of candidates of the redundant-removed spatial-temporal MVP candidate set is smaller than a threshold, wherein the threshold is two;

if the number of candidates is smaller than the threshold, adding, by the circuitry, one or more zero motion vectors to the redundancy-removed spatial-temporal MVP candidate set until an updated number of candidates of the redundancy-removed spatial-temporal MVP candidate set reaches the threshold; and

providing the redundancy-removed spatial-temporal MVP candidate set for encoding or decoding of a motion vector of a current block.

2. The method of claim 1 , wherein the top spatial MVP candidate is determined by checking top-side neighboring blocks of the current block from right to left.

3. The method of claim 2 , wherein the top-side neighboring blocks comprise an upper-left block, a right-aligned top block and an upper-right block.

4. The method of claim 1 , wherein the left spatial MVP candidate is determined by checking left-side neighboring blocks of the current block from bottom to top.

5. The method of claim 4 , wherein the left-side neighboring blocks comprise a lower-left block and a bottom-aligned left block.

6. The method of claim 1 , wherein the one or more zero motion vectors are added to the redundancy-removed spatial-temporal MVP candidate set without checking whether the redundancy-removed spatial-temporal MVP candidate set includes another zero motion vector.

7. An apparatus for deriving a motion vector predictor (MVP) candidate set for motion vector coding of a block, the apparatus comprising circuitry configured to:

determine a redundancy-removed spatial-temporal MVP candidate set, wherein the redundancy removed spatial-temporal MVP candidate set is derived from a spatial-temporal MVP candidate set by removing any redundant spatial MVP candidate; wherein the spatial-temporal MVP candidate set comprises a top spatial MVP candidate, a left spatial MVP candidate and one temporal MVP candidate;

check whether a number of candidates of the redundancy-removed spatial-temporal MVP candidate set is smaller than a threshold, wherein the threshold is two;

if the number of candidates is smaller than the threshold, add one or more zero motion vectors to the redundancy-removed spatial-temporal MVP candidate set until an updated number of candidates of the redundartcv-removed spatial-temporal MVP candidate set reaches the threshold; and

provide the redundancy-removed spatial-temporal MVP candidate set for encoding or decoding of a motion vector of a current block.

8. The apparatus of claim 7 , wherein the top spatial MVP candidate is determined by checking top-side neighboring blocks of the current block from right to left.

9. The apparatus of claim 8 , wherein the top-side neighboring blocks comprise an upper-left block, a right-aligned top block and an upper-right block.

10. The apparatus of claim 7 , wherein the left spatial MVP candidate is determined by checking left-side neighboring blocks of the current block from bottom to top.

11. The apparatus of claim 10 , wherein the left-side neighboring blocks comprise a lower-left block and a bottom-aligned left block.

12. The apparatus of claim 7 , wherein the one or more zero motion vectors are added to the redundancy-removed spatial-temporal MVP candidate set without checking whether the redundancy-removed-temporal MVP candidate set includes another zero motion vector.

13. A non-transitory computer readable medium storing a computer-executable program, the computer-executable program, when executed by a computer, causes the computer to perform a method comprising:

determining a redundancy-removed spatial-temporal MVP candidate set, wherein the redundancy-removed spatial-temporal MVP candidate set is derived from a spatial-temporal MVP candidate set by removing any redundant spatial MVP candidate; wherein the spatial-temporal MVP candidate set comprises a top spatial MVP candidate, a left spatial MVP candidate and one temporal MVP candidate;

checking whether a number of candidates of the redundancy-removed spatial-temporal MVP candidate set is smaller than a threshold, wherein the threshold is two;

if the number of candidates is smaller than the threshold, adding one or more zero motion vectors to the redundancy-removed spatial-temporal MVP candidate set until an updated number of candidates of the redundancy-removed spatial-temporal MVP candidate set reaches the threshold; and

providing the redundancy-removed spatial-temporal MVP candidate set for decoding of a motion vector of a current block.