Method and apparatus for encoding and decoding motion information
A Frame Rate Up-Conversion (FRUC) derivation process, based on frame rate up-conversion techniques, is developed in the reference software JEM (Joint Exploration Model) by the Joint Video Exploration Team (JVET). In one embodiment, a modified FRUC derivation process improves the performances of the current FRUC tool is provided. For example, some candidates of a bi-predictive pair may be discarded initially, which would save signification processing time. The discarding decision may depend on various criteria such as, e.g., a ratio between matching costs of a bi-predictive pair from two reference picture lists, a difference between the matching costs of a bi-predictive pair normalized by their respective template areas.
1. A method for video encoding or decoding, comprising:
determining, for bi-prediction of a block in a picture, a bi-predictive pair including (1) a first motion vector candidate for a first reference picture in a first reference picture list, and (2) a second motion vector candidate for a second reference picture in a second reference picture list, and corresponding first and second matching costs;
selecting one of the first motion vector candidate and the second motion vector candidate based on a ratio or a difference of the first and second matching costs;
including the selected one of the first motion vector candidate and the second motion vector candidate in a list of motion vector candidates for the block, wherein the other one of the first motion vector candidate and the second motion vector candidate is discarded;
determining a motion vector for the block based on the list of motion vector candidates; and
encoding or decoding the block based on the determined motion vector with uni-prediction.
2. The method of claim 1 , wherein the first motion vector candidate and the second motion vector candidate are determined in template mode of a Frame Rate Up-Conversion (FRUC) derivation process.
3. The method of claim 1 , wherein the first matching cost of the first motion vector candidate is based on a template of the block and a template of a block corresponding to the first motion vector candidate for the first reference picture, and the second matching cost of the second motion vector candidate is based on the template of the block and a template of a block corresponding to the second motion vector candidate for the second reference picture.
4. The method of claim 1 , wherein the second motion vector candidate is selected to be included in the list of motion vector candidates if the ratio of the first matching cost of the first motion vector candidate to the second matching cost of the second motion vector candidate exceeds a threshold.
5. The method of claim 3 , wherein the difference is based on a difference between the first matching cost of the first motion vector candidate normalized by a template area of the first motion vector candidate and the second matching cost of the second motion vector candidate normalized by a template area of the second motion vector candidate.
6. The method of claim 5 , wherein the second motion vector candidate is selected to be included in the list of motion vector candidates if the difference exceeds a threshold.
7. The method of claim 1 , wherein the block is in an AMVP mode.
8. The method of claim 1 , wherein the block is in a merge mode.
9. An apparatus for video encoding or decoding, comprising at least a processor configured to:
determine, for bi-prediction of a block in a picture, a bi-predictive pair including (1) a first motion vector candidate for a first reference picture in a first reference picture list, and (2) a second motion vector candidate for a second reference picture in a second reference picture list, and corresponding first and second matching costs;
select one of the first motion vector candidate and the second motion vector candidate based on a ratio or a difference of the first and second matching costs;
include the selected one of the first motion vector candidate and the second motion vector candidate in a list of motion vector candidates for the block, wherein the other one of the first motion vector candidate and the second motion vector candidate is discarded;
determine a motion vector for the block based on the list of motion vector candidates; and
encode or decode the block based on the determined motion vector with uni-prediction.
10. The apparatus of claim 9 , wherein the first motion vector candidate and the second motion vector candidate are determined in template mode of a Frame Rate Up-Conversion (FRUC) derivation process.
11. The apparatus of claim 9 , wherein the first matching cost of the first motion vector candidate is based on a template of the block and a template of a block corresponding to the first motion vector candidate for the first reference picture, and the second matching cost of the second motion vector candidate is based on the template of the block and a template of a block corresponding to the second motion vector candidate for the second reference picture.
12. The apparatus of claim 9 , wherein the second motion vector candidate is selected to be included in the list of motion vector candidates if the ratio of the first matching cost of the first motion vector candidate to the second matching cost of the second motion vector candidate exceeds a threshold.
13. The apparatus of claim 9 , wherein the difference is based on a difference between the first matching cost of the first motion vector candidate normalized by a template area of the first motion vector candidate and the second matching cost of the second motion vector candidate normalized by a template area of the second motion vector candidate.
14. The apparatus of claim 13 , wherein the second motion vector candidate is selected to be included in the list of motion vector candidates if the difference exceeds a threshold.
15. The apparatus of claim 9 , wherein the block is in an AMVP mode.
16. The apparatus of claim 9 , wherein the block is in a merge mode.
17. A non-transitory computer-readable medium including instructions for causing one or more processors to perform:
determining, for bi-prediction of a block in a picture, a bi-predictive pair (1) a first motion vector candidate for a first reference picture in a first reference picture list, and (2) a second motion vector candidate for a second reference picture in a second reference picture list and corresponding first and second matching costs;
selecting one of the first motion vector candidate and the second motion vector candidate based on a ratio or difference of the first and second matching costs;
including the selected one of the first motion vector candidate and the second motion vector candidate in a list of motion vector candidates for the block, wherein the other one of the first motion vector candidate and the second motion vector candidate is discarded;
determining a motion vector for the block based on the list of motion vector candidates; and
encoding or decoding the block based on the determined motion vector with uni-prediction.
18. The medium of claim 17 , wherein the first motion vector candidate and the second motion vector candidate are determined in template mode of a Frame Rate Up-Conversion (FRUC) derivation process.
19. The medium of claim 17 , wherein the second motion vector candidate is selected to be included in the list of motion vector candidates if the ratio of the first matching cost of the first motion vector candidate to the second matching cost of the second motion vector candidate exceeds a threshold.
20. The medium of claim 17 , wherein the difference is based on a difference between the first matching cost of the first motion vector candidate normalized by a template area of the first motion vector candidate and the second matching cost of the second motion vector candidate normalized by a template area of the second motion vector candidate.