Methods and systems for transform selection and management

• US 8,422,548 B2
• Filed: 03/31/2007
• Issued: 04/16/2013
• Est. Priority Date: 07/10/2006
• Status: Expired due to Fees

• 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.
• Primary Examiner(s): PYZOCHA, MICHAEL J
• Application Number:
  US11/694,959
• Publication Number:
  US 20080031347A1
• Time in Patent Office: 2,208 Days
• Field of Search: 375/240.01, 375/240.19
• US Class Current: 375/240.01
• 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 automatically selecting a transform size, said method comprising:

a) a processing device determining a base layer transform size;

b) said processing device determining if said base layer transform size matches a first predefined transform size, and determining whether an enhancement layer includes a flag indicating a second predefined transform size;

c) said processing device selecting said second predefined transform size when said enhancement layer includes said flag, and otherwise;

i) said processing device selecting a transform of said first predefined transform size for said enhancement layer when said base layer transform size matches said first predefined transform size; and

ii) said processing device otherwise selecting a transform of a default transform size for said enhancement layer.

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 transform.

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

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

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

6. A method as described in claim 1 further comprising determining a prediction mode for said enhancement layer and performing steps a) through c) only when said prediction mode indicates that said enhancement layer is predicted from said base 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 first 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 base layer quantized transform coefficients thereby creating base layer transform coefficients;

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

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

iv) combining said scaled, base 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 base layer quantized transform coefficients to match a characteristic of said enhancement-layer thereby creating scaled, base layer quantized transform coefficients; and

ii) combining said scaled, base 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.