Method and apparatus for weighted prediction for scalable video coding

• US 20090080535A1
• Filed: 05/19/2006
• Published: 03/26/2009
• Est. Priority Date: 07/21/2005
• Status: Abandoned Application

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Boyce, Jill MacDonald, Yin, Peng, Pandit, Purvin Bibhas
• Application Number:
  US11/988,653
• Publication Number:
  US 20090080535A1
• Time in Patent Office: Days
• US Class Current: 375/240.260
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/31 in the temporal domain
• CPC Class Codes: H04N 19/33 in the spatial domain
• CPC Class Codes: H04N 19/36 Scalability techniques involving formatting the layers as a function of picture distortion after decoding, e.g. signal-to-noise [SNR] scalability
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/615 using motion compensated temporal filtering [MCTF]
• CPC Class Codes: H04N 19/63 using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards

Abstract

There are provided scalable video encoder and decoders, and corresponding scalable video encoding and decoding methods. A scalable video encoder includes an encoder for encoding a block in an enhancement layer of a picture by applying a same weighting parameter to an enhancement layer reference picture as that applied to a lower layer reference picture used for encoding a block in a lower layer of the picture. The block in the enhancement layer corresponds to the block in the lower layer, and the enhancement layer reference picture corresponds to the lower layer reference picture. The scalable video decoder includes a decoder for decoding a block in an enhancement layer of a picture by applying a same weighting parameter to an enhancement layer reference picture as that applied to a lower layer reference picture used for decoding a block in a lower layer of the picture. The block in the enhancement layer corresponds to the block in the lower layer, and the enhancement layer reference picture corresponds to the lower layer reference picture.

Claims

1. An apparatus comprising:

an encoder for encoding a block in an enhancement layer of a picture by applying a same weighting parameter to an enhancement layer reference picture as that applied to a lower layer reference picture used for encoding a block in a lower layer of the picture, wherein the block in the enhancement layer corresponds to the block in the lower layer, and the enhancement layer reference picture corresponds to the lower layer reference picture.

2. The apparatus of claim 1, wherein said encoder encodes the block in the enhancement layer by selecting between an explicit weighting parameter mode and an implicit weighting parameter mode.

3. The apparatus of claim 1, wherein said encoder imposes a constraint that the same weighting parameter is always applied to the enhancement layer reference picture as that applied to the lower layer reference picture, when the block in the enhancement layer corresponds to the block in the lower layer, and the enhancement layer reference picture corresponds to the lower layer reference picture.

4. The apparatus of claim 3, wherein the constraint is defined as a profile and/or a level constraint, and/or is signaled in a sequence picture parameter set.

5. The apparatus of claim 1, wherein said encoder adds a syntax in a slice header, for a slice in the enhancement layer, to selectively apply the same weighting parameter to the enhancement layer reference picture or a different weighting parameter.

6. The apparatus of claim 1, wherein said encoder performs a remapping of a pred_weight_table( ) syntax from the lower layer to a pred_weight_table( ) syntax for the enhancement layer.

7. The apparatus of claim 6, wherein said encoder uses a picture order count to remap weighting parameters from the lower layer to a corresponding reference picture index in the enhancement layer.

8. The apparatus of claim 7, wherein the weighting parameters with a smallest reference picture index are remapped first.

9. The apparatus of claim 6, wherein said encoder sets a weighted_prediction_flag field to zero for a reference picture used in the enhancement layer that is unavailable in the lower layer.

10. The apparatus of claim 6, wherein said encoder sends, in a slice header, weighting parameters for a reference picture index corresponding to a reference picture used in the enhancement layer, when the reference picture used in the enhancement layer is without a match in the lower layer.

11. The apparatus of claim 6, wherein said encoder performs the remapping on a slice basis when the picture has a same slice partitioning in both the enhancement layer and the lower layer, and said encoder performs the remapping on a macroblock basis when the picture has a different slice partitioning in the enhancement layer with respect to the lower layer.

12. The apparatus of claim 1, wherein said encoder performs a remapping of a pred_weight_table( ) syntax from the lower layer to a pred_weight_table( ) syntax for the enhancement layer, when said encoder applies the same weighting parameter to the enhancement layer reference picture as that applied to the lower layer reference picture.

13. The apparatus of claim 1, wherein said encoder skips performing weighting parameters estimation, when said encoder applies the same weighting parameter to the enhancement layer reference picture as that applied to the lower layer reference picture.

14. The apparatus of claim 1, wherein said encoder stores only one set of weighting parameters for each reference picture index, when said encoder applies the same weighting parameter to the enhancement layer reference picture as that applied to the lower layer reference picture.

15. The apparatus of claim 1, wherein said encoder estimates the weighting parameters, when said encoder applies a different weighting parameter or the enhancement layer is without the lower layer.

16. A method for scalable video encoding, comprising:

encoding a block in an enhancement layer of a picture by applying a same weighting parameter to an enhancement layer reference picture as that applied to a lower layer reference picture used for encoding a block in a lower layer of the picture, wherein the block in the enhancement layer corresponds to the block in the lower layer, and the enhancement layer reference picture corresponds to the lower layer reference picture.

17. The method of claim 16, wherein said encoding step encodes the block in the enhancement layer by selecting between an explicit weighting parameter mode and an implicit weighting parameter mode.

18. The method of claim 16, wherein said encoding step comprises imposing a constraint that the same weighting parameter is always applied to the enhancement layer reference picture as that applied to the lower layer reference picture, when the block in the enhancement layer corresponds to the block in the lower layer, and the enhancement layer reference picture corresponds to the lower layer reference picture.

19. The method of claim 18, wherein the constraint is defined as a profile and/or a level constraint, and/or is signaled in a sequence picture parameter set.

20. The method of claim 16, wherein said encoding step comprises adding a syntax in a slice header, for a slice in the enhancement layer, to selectively apply the same weighting parameter to the enhancement layer reference picture or a different weighting parameter.

21. The method of claim 16, wherein said encoding step comprises performing a remapping of a pred_weight_table( ) syntax from the lower layer to a pred_weight_table( ) syntax for the enhancement layer.

22. The method of claim 21, wherein said performing step uses a picture order count to remap weighting parameters from the lower layer to a corresponding reference picture index in the enhancement layer.

23. The method of claim 22, wherein the weighting parameters with a smallest reference picture index are remapped first.

24. The method of claim 21, wherein said encoding step comprises setting a weighted_prediction_flag field to zero for a reference picture used in the enhancement layer that is unavailable in the lower layer.

25. The method of claim 21, wherein said encoding step comprises sending, in a slice header, weighting parameters for a reference picture index corresponding to a reference picture used in the enhancement layer, when the reference picture used in the enhancement layer is without a match in the lower layer.

26. The method of claim 21, wherein the remapping is performed on a slice basis when the picture has a same slice partitioning in both the enhancement layer and the lower layer, and said remapping step is performed on a macroblock basis when the picture has a different slice partitioning in the enhancement layer with respect to the lower layer.

27. The method of claim 16, wherein said encoding step comprises performing a remapping of a pred_weight_table( ) syntax from the lower layer to a pred_weight_table( ) syntax for the enhancement layer, when said encoding step applies the same weighting parameter to the enhancement layer reference picture as that applied to the lower layer reference picture.

28. The method of claim 16, wherein said encoding step comprises skipping weighting parameters estimation, when said encoding step applies the same weighting parameter to the enhancement layer reference picture as that applied to the lower layer reference picture.

29. The method of claim 16, wherein said encoding step comprises storing only one set of weighting parameters for each reference picture index, when said encoding step applies the same weighting parameter to the enhancement layer reference picture as that applied to the lower layer reference picture.

30. The method of claim 16, wherein said encoding step comprises estimating the weighting parameters, when said encoding step applies a different weighting parameter or the enhancement layer is without the lower layer.

31. A video signal structure for scalable video encoding comprising:

a block encoded in an enhancement layer of a picture generated by applying a same weighting parameter to an enhancement layer reference picture as that applied to a lower layer reference picture used for encoding a block in a lower layer of the picture, wherein the block in the enhancement layer corresponds to the block in the lower layer, and the enhancement layer reference picture corresponds to the lower layer reference picture.