Methods and systems for motion vector derivation at a video decoder
Method and apparatus for deriving a motion vector at a video decoder. A block-based motion vector may be produced at the video decoder by utilizing motion estimation among available pixels relative to blocks in one or more reference frames. The available pixels could be, for example, spatially neighboring blocks in the sequential scan coding order of a current frame, blocks in a previously decoded frame, or blocks in a downsampled frame in a lower pyramid when layered coding has been used.
1. A video decoder apparatus comprising:
a memory; and
a processor in communication with the memory, the processor to:
determine a target block of a current frame;
identify a first block of a previous frame based on the first block being a neighbor of a second block of the previous frame collocated with the target block; and
decode the target block of the current frame based at least in part on a motion vector corresponding to the first block, wherein the motion vector is relative to a block of a reference frame distinct from the previous frame.
2. The apparatus of claim 1 , wherein the processor is further to:
identify a third block of the current frame above and to the left of the target block; and
decode the target block of the current frame based at least in part on a second motion vector corresponding to the third block.
3. The apparatus of claim 2 , wherein the processor is further to:
identify a fourth block of the current frame above and immediately adjacent the target block; and
decode the target block of the current frame based at least in part on a third motion vector corresponding to the fourth block.
4. The apparatus of claim 3 , wherein the processor is further to:
identify a fifth block of the current frame to the left and immediately adjacent the target block; and
decode the target block of the current frame based at least in part on a fourth motion vector corresponding to the fifth block.
5. The apparatus of claim 1 , wherein the previous frame is temporally previous to the current frame.
6. The apparatus of claim 1 , wherein the processor is further to:
decode the first block and the second block prior to the decode of the target block of the current frame.
7. The apparatus of claim 1 , wherein the current frame comprises a P-frame or a B-frame.
8. The apparatus of claim 1 , wherein the processor is to decode the target block based at least in part on the motion vector in response to a flag to indicate use of at least one motion vector for the block of decoded pixels.
9. The apparatus of claim 1 , further comprising:
a radio; and
at least one antenna communicatively coupled to the radio.
10. The apparatus of claim 9 , further comprising:
a display communicatively coupled to the one or more processor circuitry, the display to display an image based at least in part on the decoded target block.
11. At least one non-transitory computer-readable medium comprising instructions stored thereon, which if executed by one or more processors, cause the one or more processors to:
determine a target block of a current frame;
identify a first block of a previous frame based on the first block being a neighbor of a second block of the previous frame collocated with the target block; and
decode the target block of the current frame based at least in part on a motion vector corresponding to the first block, wherein the motion vector is relative to a block of a reference frame distinct from the previous frame.
12. The medium of claim 11 , comprising further instructions stored thereon, which if executed by the one or more processors, cause the one or more processors to:
identify a third block of the current frame above and to the left of the target block; and
decode the target block of the current frame based at least in part on a second motion vector corresponding to the third block.
13. The medium of claim 12 , comprising further instructions stored thereon, which if executed by the one or more processors, cause the one or more processors to:
identify a fourth block of the current frame above and immediately adjacent the target block; and
decode the target block of the current frame based at least in part on a third motion vector corresponding to the fourth block.
14. The medium of claim 13 , comprising further instructions stored thereon, which if executed by the one or more processors, cause the one or more processors to:
identify a fifth block of the current frame to the left and immediately adjacent the target block; and
decode the target block of the current frame based at least in part on a fourth motion vector corresponding to the fifth block.
15. The medium of claim 11 , wherein the previous frame is temporally previous to the current frame and the medium comprises further instructions stored thereon, which if executed by the one or more processors, cause the one or more processors to decode the first block and the second block prior to the decode of the target block of the current frame.
16. A computer-implemented method of video decoding comprising:
determining a target block of a current frame;
identifying a first block of a previous frame based on the first block being a neighbor of a second block of the previous frame collocated with the target block; and
decoding the target block of the current frame based at least in part on a motion vector corresponding to the first block, wherein the motion vector is relative to a block of a reference frame distinct from the previous frame.
17. The method of claim 16 , further comprising:
identifying a third block of the current frame above and to the left of the target block; and
decoding the target block of the current frame based at least in part on a second motion vector corresponding to the third block.
18. The method of claim 17 , comprising further instructions stored thereon, which if executed by the one or more processors, cause the one or more processors to:
identify a fourth block of the current frame above and immediately adjacent the target block; and
decode the target block of the current frame based at least in part on a third motion vector corresponding to the fourth block.
19. The method of claim 18 , comprising further instructions stored thereon, which if executed by the one or more processors, cause the one or more processors to:
identify a fifth block of the current frame to the left and immediately adjacent the target block; and
decode the target block of the current frame based at least in part on a fourth motion vector corresponding to the fifth block.
20. The method of claim 16 , wherein the previous frame is temporally previous to the current frame and the medium comprises further instructions stored thereon, which if executed by the one or more processors, cause the one or more processors to decode the first block and the second block prior to the decode of the target block of the current frame.