Methods and Systems for Transform Selection and Management

• US 20080031347A1
• Filed: 03/31/2007
• Published: 02/07/2008
• Est. Priority Date: 07/10/2006
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Segall, Christopher A.
• Granted Patent: US 8,422,548 B2
• Time in Patent Office: Days
• US Class Current: 375/240.19
• CPC Class Codes: H04N 19/122 Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/33 in the spatial domain
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence

Abstract

Embodiments of the present invention comprise systems and methods for managing and combining layers in a multi-layer bitstream.

Claims

1. A method for selecting a reconstruction transform size when a transform size is not indicated in an enhancement layer, said method comprising:

a) determining a lower-layer transform size;

b) determining if said lower-layer transform size is substantially similar to a predefined transform size;

c) selecting an inverse transform of said predefined transform size as a reconstruction transform when said lower-layer transform size is substantially similar to said predefined transform size; and

d) selecting an inverse transform of a default transform size as a reconstruction transform when said lower-layer transform size is not substantially similar to said predefined transform size.

2. A method as described in claim 1 wherein said default transform size is used for parsing a bitstream regardless of the selection for a reconstruction transform.

3. A method as described in claim 1 further comprising inverse transforming enhancement layer coefficients with said reconstruction transform.

4. A method as described in claim 1 wherein said predefined transform size is 8×

8.

5. A method as described in claim 1 wherein said predefined transform size is 16×

16.

6. A method as described in claim 1 further comprising determining a prediction mode for said enhancement layer and performing steps a) through d) only when said enhancement layer prediction mode indicates that said enhancement layer is predicted from said lower layer.

7. A method as described in claim 1 further comprising extracting a plurality of enhancement-layer coefficients formatted for said default transform size.

8. A method as described in claim 7 further comprising reformatting for said predefined transform size said plurality of extracted enhancement-layer coefficients.

9. A method as described in claim 1 further comprising extracting a plurality of quantized enhancement-layer coefficients formatted for said default transform size.

10. A method as described in claim 9 further comprising reformatting for said predefined transform size said plurality of extracted quantized enhancement-layer coefficients thereby creating reformatted quantized enhancement-layer coefficients.

11. A method as described in claim 10 further comprising:

i) inverse quantizing a plurality of lower-layer quantized transform coefficients thereby creating lower-layer transform coefficients;

ii) scaling said lower-layer transform coefficients to match a characteristic of said enhancement-layer thereby creating scaled, lower-layer transform coefficients;

iii) inverse quantizing said reformatted quantized enhancement-layer coefficients thereby creating enhancement-layer transform coefficients; and

iv) combining said scaled, lower-layer transform coefficients with said enhancement-layer transform coefficients to form combined coefficients.

12. A method as described in claim 11 further comprising generating a combined bitstream comprising said combined coefficients.

13. A method as described in claim 12 wherein said combined bitstream further comprises an intra-prediction mode.

14. A method as described in claim 12 wherein said combined bitstream further comprises a motion vector.

15. A method as described in claim 11 further comprising inverse transforming said combined coefficients using said reconstruction transform thereby generating a spatial-domain residual value.

16. A method as described in claim 15 further comprising combining said spatial-domain residual value with said spatial-domain prediction value.

17. A method as described in claim 10 further comprising:

i) scaling a plurality of lower-layer quantized transform coefficients to match a characteristic of said enhancement-layer thereby creating scaled, lower-layer quantized transform coefficients; and

ii) combining said scaled, lower-layer quantized transform coefficients with said reformatted quantized enhancement-layer coefficients to form combined quantized coefficients.

18. A method as described in claim 17 further comprising inverse quantizing said combined quantized coefficients, thereby creating combined coefficients.

19. A method as described in claim 18 further comprising generating a combined bitstream comprising said combined coefficients.

20. A method as described in claim 19 wherein said combined bitstream further comprises an intra-prediction mode.

21. A method as described in claim 19 wherein said combined bitstream further comprises a motion vector.

22. A method as described in claim 18 further comprising inverse transforming said combined coefficients using said reconstruction transform thereby generating a spatial-domain residual value.

23. A method as described in claim 22 further comprising combining said spatial-domain residual value with said spatial-domain prediction value.