Spatially-scalable video coding

• US 20080008252A1
• Filed: 07/07/2006
• Published: 01/10/2008
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Wu, Feng, Xiong, Ruiqin, Xu, Ji-Zheng
• Granted Patent: US 9,332,274 B2
• Time in Patent Office: Days
• US Class Current: 375/240.29
• CPC Class Codes: H04N 19/33 in the spatial domain
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

Video data for a high resolution image unit is coded with regard to both a low resolution reference image unit and a high resolution reference image unit. In an example encoding implementation, both low pass information and high pass information of residue data for a current image are generated. In an example decoding implementation, a current image is reconstructed by synthesizing both low pass information and high pass information for the reconstructed image.

Claims

1. A method for encoding a current image, the method comprising:

generating low pass information of residue data for the current image based on low pass information for the current image;

ascertaining high pass information for the current image responsive to the current image;

ascertaining high pass information of prediction data for the current image responsive to prediction data for the current image; and

generating high pass information of residue data for the current image based on the high pass information for the current image and the high pass information of prediction data for the current image.

2. The method as recited in claim 1, wherein the generating low pass information of residue data for the current image based on low pass information for the current image comprises:

calculating a difference between the low pass information for the current image and low pass information of prediction data for the current image.

3. The method as recited in claim 2, further comprising:

creating the low pass information for the current image by down-sampling the current image; and

determining the low pass information of prediction data for the current image by applying a motion compensation process to low pass information for a reference image.

4. The method as recited in claim 1, wherein the ascertaining high pass information for the current image responsive to the current image comprises:

creating the low pass information for the current image by down-sampling the current image;

creating up-sampled information for the current image by up-sampling the low pass information for the current image; and

calculating a difference between the current image and the up-sampled information for the current image to ascertain the high pass information for the current image.

5. The method as recited in claim 1, wherein the ascertaining high pass information for the current image responsive to the current image comprises:

ascertaining the high pass information for the current image responsive to a reconstructed version of the low pass information for the current image.

6. The method as recited in claim 1, wherein the ascertaining high pass information of prediction data for the current image responsive to prediction data for the current image comprises:

creating low pass information of prediction data for the current image by down-sampling the prediction data for the current image;

creating up-sampled information of prediction data for the current image by up-sampling the low pass information of prediction data for the current image; and

calculating a difference between the prediction data for the current image and the up-sampled information of prediction data for the current image.

7. The method as recited in claim 6, further comprising:

determining the prediction data for the current image by applying a motion compensation process to a reference image.

8. The method as recited in claim 1, wherein the ascertaining high pass information of prediction data for the current image responsive to prediction data for the current image comprises:

convolving a filter and the prediction data for the current image, wherein taps of the filter are acquired by minimizing an energy of residue signals given a constraint on a number of the taps of the filter.

9. The method as recited in claim 1, wherein the generating high pass information of residue data for the current image based on the high pass information for the current image and the high pass information of prediction data for the current image comprises:

calculating a difference between the high pass information for the current image and high pass information of prediction data for the current image.

10. The method as recited in claim 1, further comprising:

transmitting the low pass information of residue data for the current image; and

transmitting the high pass information of residue data for the current image that corresponds to an identified resolution level of a destination device.

13. The method as recited in claim 1, wherein the generating high pass information for the reconstructed image based on high pass information of residue data for the current image comprises:

combining the high pass information of residue data for the current image and high pass information of prediction data, the high pass information of prediction data determined from prediction data for the current image.

14. The method as recited in claim 13, further comprising:

determining the prediction data for the current image from a reference image at a high resolution and a motion field at the high resolution.

11. A method for decoding a current image, the method comprising:

generating low pass information for a reconstructed image based on low pass information of residue data for the current image;

generating high pass information for the reconstructed image based on high pass information of residue data for the current image; and

producing a reconstructed current image by synthesizing the low pass information for the reconstructed image and the high pass information for the reconstructed image.

12. The method as recited in claim 11, wherein the generating low pass information for a reconstructed image based on low pass information of residue data for the current image comprises:

combining the low pass information of residue data for the current image and low pass information of prediction data, the low pass information of prediction data determined from low pass information for a reference image.

15. The method as recited in claim 11, wherein the producing a reconstructed current image by synthesizing the low pass information for the reconstructed image and the high pass information for the reconstructed image comprises:

up-sampling the low pass information for the reconstructed image to create up-sampled low pass information for the reconstructed image; and

combining the up-sampled low pass information for the reconstructed image and the high pass information for the reconstructed image to produce the reconstructed current image.

16. A device comprising:

a video coder that codes a current image unit at a given resolution level using prediction data determined at the given resolution level and prediction data determined at a lower resolution level.

17. The device as recited in claim 16, wherein the prediction data determined at the lower resolution level is determined from low pass information for a reference image having a time that corresponds to a time of the current image unit.

18. The device as recited in claim 16, wherein the prediction data determined at the given resolution level is determined from a reference image having a time that differs from a time of the current image unit.

19. The device as recited in claim 16, wherein the video coder generates (i) low pass information of residue data based on the prediction data determined at the lower resolution level and (ii) high pass information of residue data based on the prediction data determined at the given resolution level.

20. The device as recited in claim 16, wherein the video coder synthesizes a reconstructed version of the current image from (i) low pass information for a reconstructed image that is based on the prediction data determined at the lower resolution level and (ii) high pass information for the reconstructed image that is based on the prediction data determined at the given resolution level.