Methods and apparatus for transform selection in video encoding and decoding

Patent metadata

Field	Value
Publication number	US-9774864-B2
Application number	US-200913138179-A
Country	US
Kind code	B2
Filing date	Oct 21, 2009
Priority date	Jan 27, 2009
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

There are provided methods and apparatus for transform selection in video coding. An apparatus includes a video encoder for encoding at least a block in a picture by selecting a transform to apply to a residue of the block from a set of two or more available transforms. The transform is selected based on at least one of an inter prediction mode used to predict at least one reference for the block, one or more values corresponding to a motion vector, a value of a residue of one or more previously encoded blocks, a value of prediction data for the block, one or more transform selections of one or more neighboring reconstructed blocks, and a quantization step applied to transform coefficients for the residue of the block.

First claim

The invention claimed is:

1. An apparatus, comprising:
a video encoder for encoding at least a block in a picture in a video sequence by selecting a transform to apply to a residue of the block from a set of two or more transforms,
wherein the set of transforms is determined from a reference picture to which a motion vector for the block points.

2. The apparatus of claim 1 , wherein said video encoder determines the set of transforms and sends the set of transforms to a corresponding decoder as side information.

3. The apparatus of claim 1 , wherein said video encoder determines the set of transforms, determines a refinement on the set of transforms that allows a corresponding decoder to predict the set of transforms from the refinement and from previously decoded data in order to derive a same set of transforms as said video encoder, and sends the refinement to the corresponding decoder.

4. The apparatus of claim 1 , wherein said video encoder determines the set of transforms from a plurality of sets of transforms and sends the set of transforms as side information.

5. The apparatus of claim 1 , wherein said video encoder determines the set of transforms from a family of transforms, the set of transforms representing a subset of the family of transforms, and wherein said video encoder sends only the subset of the family of transforms.

6. In a video encoder, a method, comprising:
determining a set of one or more transforms; and
encoding at least a block in a picture in a video sequence by selecting a transform to apply to a residue of the block from the set of transforms,
wherein the set of transforms is determined from a reference picture to which a motion vector for the block points.

7. The method of claim 6 , further comprising sending the set of transforms to a corresponding decoder as side information.

8. The method of claim 6 , further comprising:
determining a refinement on the set of transforms that allows a corresponding decoder to predict the set of transforms from the refinement and from previously decoded data in order to derive a same set of transforms as said video encoder; and
sending the refinement to the corresponding decoder.

9. The method of claim 6 , wherein the set of transforms is determined from a plurality of sets of transforms, and the method further comprises sending the set of transforms as side information.

10. The method of claim 6 , wherein the set of transforms is determined from a family of transforms, the set of transforms representing a subset of the family of transforms, and wherein the method further comprises sending only the subset of the family of transforms.

11. An apparatus, comprising:
a video decoder for decoding at least a block in a picture in a video sequence by selecting an inverse transform to apply to inverse quantized coefficients of the block from a set of two or more inverse transforms,
wherein the set of inverse transforms is determined from a reference picture to which a motion vector for the block points.

12. The apparatus of claim 11 , wherein said video decoder receives the set of inverse transforms as side information.

13. The apparatus of claim 11 , wherein said video decoder receives a refinement on the set of inverse transforms that allows said video decoder to predict the set of inverse transforms from the refinement and from previously decoded data in order to derive a same set of inverse transforms as a corresponding video encoder.

14. The apparatus of claim 11 , wherein the set of inverse transforms is determined from a plurality of sets of inverse transforms, and the set of inverse transforms is received by said video decoder as side information.

15. The apparatus of claim 11 , wherein the set of inverse transforms is determined from a family of inverse transforms, the set of inverse transforms representing a subset of the family of inverse transforms, and wherein said video decoder receives only the subset of the family of inverse transforms.

16. In a video decoder, a method, comprising:
decoding at least a block in a picture in a video sequence by selecting an inverse transform to apply to inverse quantized coefficients of the block from a set of two or more inverse transforms,
wherein the set of inverse transforms is determined from a reference picture to which a motion vector for the block points.

17. The method of claim 16 , further comprising receiving the set of transforms as side information.

18. The method of claim 16 , further comprising:
receiving a refinement on the set of transforms that allows the video decoder to predict the set of transforms from the refinement and from previously decoded data in order to derive a same set of transforms as a corresponding video encoder; and
predicting the set of transforms from the refinement and from the previously decoded data.

19. The method of claim 16 , wherein the set of transforms is determined from a plurality of sets of transforms, and the method further comprises receiving the set of transforms as side information.

20. The method of claim 16 , wherein the set of transforms is determined from a family of transforms, the set of transforms representing a subset of the family of transforms, and wherein the method further comprises receiving only the subset of the family of transforms.

21. The apparatus of claim 1 , wherein the set of transforms is determined also from a residue of previous blocks.

22. The method of claim 6 , wherein the set of transforms is determined also from a residue of previous blocks.

23. The apparatus of claim 11 , wherein the set of transforms is determined also from a residue of previous blocks.

24. The method of claim 16 , wherein the set of transforms is determined also from a residue of previous blocks.

Assignees

• Sole Joel
• Yin Peng
• Zheng Yunfei
• Gomila Cristina
• Thomson Licensing Dtv

Inventors

• Sole Joel
• Yin Peng
• Zheng Yunfei
• Gomila Cristina

Classifications

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/197

  including determination of the initial value of an encoding parameter (H04N19/56 takes precedence) · CPC title

• H04N19/198

  including smoothing of a sequence of encoding parameters, e.g. by averaging, by choice of the maximum, minimum or median value · CPC title

• H04N19/46

  Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) · CPC title

• H04N19/61 Primary

  in combination with predictive coding · CPC title