Adaptive reference picture selection based on inter-picture motion measurement

• US 7,602,849 B2
• Filed: 11/17/2003
• Issued: 10/13/2009
• Est. Priority Date: 11/17/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: Booth, Simon, Cote, Guy
• Primary Examiner(s): SENFI, BEHROOZ M
• Application Number:
  US10/714,736
• Publication Number:
  US 20050105618A1
• Time in Patent Office: 2,157 Days
• Field of Search: 348/699, 348/409, 348/420, 348/384, 348/390, 348/400, 348/401, 348/402, 348/407, 348/410, 348/411, 348/413, 348/415, 348/416, 348/700, 382/232, 382/236, 382/238, 375/240.24, 375/240.16, 375/240.12, 375/240.01, 375/240.02
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/527 Global motion vector estimation
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate a control signal in response to a measurement of inter-picture motion between a current picture and a first reference picture. The second circuit may be configured to select the first reference picture or a second reference picture as a better reference picture for motion estimation in response to the control signal.

Claims

1. An apparatus comprising:

a first circuit configured to acquire a current picture, a first reference picture and a second reference picture;

a second circuit configured to generate a measurement of inter-picture motion between said current picture and said first reference picture by performing a global motion estimation process on said current picture and said first reference picture;

a third circuit configured to generate a control signal in response to (i) said measurement of inter-picture motion between said current picture and said first reference picture and (ii) a predetermined threshold value;

a fourth circuit configured to select either said first reference picture or said second reference picture as a better reference picture for subsequent motion estimation and motion compensation on said current picture in response to said control signal; and

a motion estimation circuit configured to generate one or more motion vectors in response to said better reference picture and said current picture, wherein said current picture is encoded based upon said one or more motion vectors.

2. The apparatus according to claim 1, wherein:

a parity of said first reference picture is opposite to a parity of said current picture; and

a parity of said second reference picture is the same as said parity of said current picture.

3. The apparatus according to claim 1, wherein:

a parity of said first reference picture is the same as a parity of said current picture; and

a parity of said second reference picture is opposite to said parity of said current picture.

4. The apparatus according to claim 1, further comprising:

a memory configured to store said current picture, said first reference picture and said second reference picture.

5. The apparatus according to claim 1, wherein said fourth circuit further comprises:

a multiplexer circuit configured to select (i) said first reference picture for presentation as said better reference picture in response to a first state of said control signal and (ii) said second reference picture for presentation as said better reference picture in response to a second state of said control signal.

6. The apparatus according to claim 1, wherein said second circuit further comprises:

a low-complexity motion estimation circuit configured to generate a plurality of coarse motion vectors for said current picture based upon a low-resolution inter-picture motion search of said first reference picture.

7. The apparatus according to claim 6, wherein said second circuit further comprises:

a first analysis circuit configured to determine a dominant global motion component based upon said coarse motion vectors and generate said measurement of inter-picture motion in response to said dominant global motion component.

8. The apparatus according to claim 7, wherein said second circuit further comprises:

a second analysis circuit configured to generate said control signal based upon a fraction of said coarse motion vectors contained in a cluster associated with said dominant global motion component and said predetermined threshold value.

9. The apparatus according to claim 7, wherein:

said first analysis circuit is configured to perform a cluster analysis on said coarse motion vectors.

10. The apparatus according to claim 1, wherein said apparatus is part of an encoder circuit.

22. The apparatus according to claim 1, wherein said first reference picture comprises a temporally closest reference picture to said current picture.

11. An apparatus comprising:

means for acquiring a current picture, a first reference picture and a second reference picture;

means for generating a measurement of inter-picture motion between said current picture and said first reference picture by performing a global motion estimation process on said current picture and said first reference picture;

means for generating a control signal in response to (i) said measurement of inter-picture motion between said current picture and said first reference picture and (ii) a predetermined threshold value;

means for selecting either said first reference picture or said second reference picture as a better reference picture for subsequent motion estimation and motion compensation on said current picture in response to said control signal; and

means for generating one or more motion vectors in response to said better reference picture and said current picture, wherein said current picture is encoded based upon said one or more motion vectors.

12. A method for performing motion estimation, comprising the steps of:

acquiring a current picture, a first reference picture and a second reference picture using a video encoder;

generating a measurement of inter-picture motion between said current picture and said first reference picture by performing a global motion estimation process on said current picture and said first reference picture;

generating a control signal in response to (i) said measurement of inter-picture motion between said current picture and said first reference picture and (ii) a predetermined threshold value, wherein said video encoder selects either said first reference picture or said second reference picture as a better reference picture for subsequent motion estimation and motion compensation on said current picture in response to said control signal; and

generating one or more motion vectors in response to said better reference picture and said current picture, wherein said current picture is encoded based upon said one or more motion vectors.

13. The method according to claim 12, wherein:

a parity of said first reference picture is opposite to a parity of said current picture; and

a parity of said second reference picture is the same as said parity of said current picture.

14. The method according to claim 12, wherein:

a parity of said first reference picture is the same as a parity of said current picture; and

a parity of said second reference picture is opposite to said parity of said current picture.

15. The method according to claim 12, further comprising the step of:

storing said current picture, said first reference picture and said second reference picture in a picture memory.

16. The method according to claim 12, further comprising the step of:

generating a plurality of coarse motion vectors for said generating a plurality of coarse motion vectors for said current picture based upon a low-resolution inter-picture motion search of said first reference picture.

17. The method according to claim 16, further comprising the steps of:

determining a dominant global motion component based upon said coarse motion vectors; and

generating said measurement of inter-picture motion in response to said dominant global motion component.

18. The method according to claim 17, further comprising the step of:

generating said control signal having (i) a first state in response to said measurement of inter-picture motion exceeding said predetermined threshold value and (ii) a second state in response to said measurement of inter-picture motion not exceeding said predetermined threshold value.

19. The method according to claim 17, further comprising:

performing a cluster analysis on said coarse motion vectors.

20. The method according to claim 12, wherein said current picture, said first reference picture and said second reference picture each comprise a field picture.

21. The method according to claim 12, wherein said predetermined threshold value is programmable.

23. The method according to claim 17, further comprising the step of:

generating said control signal based upon a fraction of said coarse motion vectors contained in a cluster associated with said dominant global motion component and said predetermined threshold value.