Method for performing hybrid multihypothesis prediction during video coding of a coding unit, and associated apparatus
A method and apparatus for performing hybrid multihypothesis prediction during video coding of a coding unit includes: processing a plurality of sub-coding units in the coding unit; and performing disparity vector (DV) derivation when the coding unit is processed by a 3D or multi-view coding tool or performing block vector (BV) derivation when the coding unit is processed by intra picture block copy (IntraBC) mode. The step of performing DV or BV derivation includes deriving a plurality of vectors for multihypothesis motion-compensated prediction of a specific sub-coding unit from at least one other sub-coding/coding unit. The one other sub-coding/coding unit is coded before the corresponding DV or BV is derived for multihypothesis motion-compensated prediction of the specific sub-coding unit. A linear combination of a plurality of pixel values derived from the plurality of vectors is used as a predicted pixel value of the specific sub-coding unit.
1. A method for performing multihypothesis prediction during video coding of a coding unit, the method comprising:
processing a plurality of sub-coding units in the coding unit;
performing disparity vector (DV) derivation when the coding unit is processed by a three-dimensional (3D) or multi-view coding tool, or performing block vector (BV) derivation when the coding unit is processed by intra picture block copy (IntraBC) mode, wherein the step of performing DV or BV derivation further comprises:
deriving a plurality of vectors for multihypothesis prediction of a specific sub-coding unit in the coding unit, wherein the plurality of vectors are selecting from at least two DVs, at least two BVs, or a combination of DV, BV, and motion vector (MV), at least one of the vectors is the DV or BV of one other sub-coding/coding unit, and the one other sub-coding/coding unit is coded before the corresponding DV or BV is derived for multihypothesis prediction of the specific sub-coding unit; and
performing multihypothesis prediction on the specific sub-coding unit according to the plurality of vectors, wherein the step of performing multihypothesis prediction on the specific sub-coding unit according to the plurality of vectors further comprises:
utilizing a linear combination of a plurality of pixel values derived from the plurality of vectors as a predicted pixel value of the specific sub-coding unit.
2. The method of claim 1 , wherein the step of performing multihypothesis prediction on the specific sub-coding unit according to the plurality of vectors further comprises:
calculating an average of the plurality of pixel values to derive the predicted pixel value of the specific sub-coding unit.
3. The method of claim 1 , wherein the step of performing disparity vector derivation or block vector derivation further comprises:
performing disparity vector derivation based on an explicit flag when the coding unit is processed by the 3D or multi-view coding tool, or performing block vector derivation based on an explicit flag when the coding unit is processed by the intra picture block copy mode.
4. The method of claim 1 , wherein the plurality of vectors are derived from a remaining portion of the sub-coding units in the coding unit.
5. The method of claim 1 , wherein the at least one other sub-coding/coding unit comprises at least one spatially coded sub-coding/coding unit and/or at least one temporally coded sub-coding/coding unit.
6. The method of claim 1 , wherein the at least one other sub-coding/coding unit is a disparity-compensated sub-coding/coding unit for DV derivation.
7. The method of claim 1 , wherein the at least one other sub-coding/coding unit is processed by the intra picture block copy mode for BV derivation.
8. The method of claim 1 , wherein the at least one other sub-coding unit/coding unit is a sub-coding unit in a neighboring coding unit.
9. The method of claim 1 , wherein the at least one other sub-coding unit/coding unit is a disparity-compensated sub-coding/coding unit in another view.
10. The method of claim 1 , wherein the plurality of vectors are derived from a single sub-coding unit/coding unit.
11. The method of claim 1 , wherein one of the plurality of vectors is List 0 vector, and another one of the plurality of vectors is List 1 vector.
12. An apparatus for performing multihypothesis prediction during video coding of a coding unit, the apparatus comprising:
a processing circuit arranged to perform video coding on the coding unit, wherein the processing circuit comprises:
a preprocessing module arranged to process a plurality of sub-coding units in the coding unit and perform disparity vector (DV) derivation when the coding unit is processed by a three-dimensional (3D) or multi-view coding tool, or perform block vector (BV) derivation when the coding unit is processed by intra picture block copy (IntraBC) mode, wherein the preprocessing module derives a plurality of vectors for multihypothesis prediction of a specific sub-coding unit of the portion of the sub-coding units, wherein the plurality of vectors are selecting from at least two DVs, at least two BVs, or a combination of DV, BV, and motion vector (MV), wherein at least one of the vectors is the DV or BV of one other sub-coding/coding unit and the one other sub-coding/coding unit is coded before the corresponding DV or BV is derived for multihypothesis prediction of the specific sub-coding unit, and performs multihypothesis prediction on the specific sub-coding unit according to the plurality of vectors, and the preprocessing module utilizes a linear combination of a plurality of pixel values derived from the plurality of vectors as a predicted pixel value of the specific sub-coding unit; and
at least one coding module arranged to perform video coding on the coding unit based upon the multihypothesis prediction performed by the preprocessing module.
13. The apparatus of claim 12 , wherein the preprocessing module calculates an average of the plurality of pixel values to derive the predicted pixel value of the specific sub-coding unit.
14. The apparatus of claim 12 , wherein the preprocessing module performs disparity vector derivation based on an explicit flag when the coding unit is processed by the 3D or multi-view coding tool.
15. The apparatus of claim 12 , wherein the preprocessing module performs block vector derivation based on an explicit flag when the coding unit is processed by the IntraBC mode.
16. The apparatus of claim 12 , wherein the preprocessing module derives the vectors from a remaining portion of the sub-coding units in the coding unit.
17. The apparatus of claim 12 , wherein the at least one other sub-coding/coding unit comprises at least one spatially coded sub-coding/coding unit and/or at least one temporally coded sub-coding/coding unit.
18. The apparatus of claim 12 , wherein the at least one other sub-coding/coding unit is a disparity-compensated sub-coding/coding unit when the preprocessing module performs DV derivation.
19. The apparatus of claim 12 , wherein the at least one other sub-coding/coding unit is processed by the intra picture block copy mode when the preprocessing module performs BV derivation.
20. The apparatus of claim 12 , wherein the plurality of vectors are derived from a single sub-coding unit/coding unit.
21. The apparatus of claim 12 , wherein one of the plurality of vectors is List 0 vector, and another one of the plurality of vectors is List 1 vector.