Method and apparatus for weighted prediction in predictive frames

• US 20050281334A1
• Filed: 05/02/2005
• Published: 12/22/2005
• Est. Priority Date: 05/04/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Walker, Gordon Kent, Raveendran, Vijayalakshmi R.
• Granted Patent: US 8,731,054 B2
• Time in Patent Office: Days
• 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 19/109 among a plurality of temporal predictive coding modes
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures

Abstract

A method and apparatus for constructing weighted bi-directional predicted video pictures including locating first and second prediction regions in first and second reference frames, receiving first and second weight parameters related to the first and second prediction regions, where the weight parameters and weighting methodology used to encode the weight parameters can be from several different codec designs for weighted bi-directional prediction. Further including, modifying the weight parameters to conform to a bit configuration and weighting methodology, applying the weight parameters to the first and second prediction regions and combining them to form a weighted bi-directional predicted picture. The bit configuration being chosen to accommodate multiple encoded bit configurations and methodologies, where the encoded bit configurations and methodologies can differ in characteristics such as, for example, bit size, being signed or unsigned, and supporting offsets.

Claims

1. A method for constructing a predicted picture, comprising:

modifying a first weight parameter associated with a region of a first frame to conform to a bit configuration;

modifying a second weight parameter associated with a region of a second frame to conform to the bit configuration;

calculating a first predicted component by applying the modified first weight parameter to the region of the first frame;

calculating a second predicted component by applying the modified second weight parameter to the region of the second frame; and

calculating a combined weighted prediction by combining the first predicted component and the second predicted component.

2. The method of claim 1, further comprising:

choosing the bit configuration to accommodate a plurality of encoded bit configurations, wherein at least two of the plurality of encoded bit configurations have different numbers of bits.

3. The method of claim 1, further comprising:

choosing the bit configuration to accommodate a plurality of encoded bit configurations, wherein at least one of the plurality of encoded bit configurations is signed and at least one of the plurality of encoded bit configurations is unsigned.

4. The method of claim 1, further comprising:

locating the region of the first frame by using a first motion vector; and

locating the region of the second frame by using a second motion vector.

5. The method of claim 1, further comprising:

locating the region of the first frame and locating the region of the second frame by using direct mode temporal interpolation of a decoded motion vector between the first frame and the second frame.

6. The method of claim 1, further comprising:

locating the region of the first frame by identifying that the region of the first frame is a null region; and

calculating the first predicted component to be equal to zero.

7. The method of claim 1, further comprising:

locating the region of the second frame by identifying that the region of the second frame is a null region; and

calculating the second predicted component to be equal to zero.

8. The method of claim 1, wherein the first weight parameter and the second weight parameter are a same encoded bit configuration.

9. The method of claim 1, further comprising:

identifying that the first weight parameter is zero; and

calculating the first predicted component to be equal to zero.

10. The method of claim 1, further comprising:

identifying that the second weight parameter is zero; and

calculating the second predicted component to be equal to zero.

11. The method of claim 1, wherein the first weight parameter and the second weight parameter are signed.

12. The method of claim 1, further comprising:

normalizing the combined weighted prediction by bit shifting the combined weighted prediction a number of bits based on a base two logarithm of a denominator associated with the first weight parameter and the second weight parameter.

13. The method of claim 1, further comprising:

receiving a first offset parameter associated with the region of the first frame;

receiving a second offset parameter associated with the region of the second frame;

receiving a residual error associated with the combined weighted prediction; and

combining the residual error, the first offset parameter and the second offset parameter with the combined weighted prediction.

14. The method of claim 1, further comprising:

receiving encoded video data representing the first weight parameter, the second weight parameter, the region of the first frame and the region of the second frame over a network.

15. The method of claim 1, further comprising:

receiving encoded video data representing the first weight parameter, the second weight parameter, the region of the first frame and the region of the second frame over a wireless network.

16. The method of claim 1, further comprising:

displaying the combined weighted prediction.

17. The method of claim 1, further comprising:

modifying the first weight parameter by performing an operation selected from the group consisting of bit shifting, sign extending, zero extending and applying a scaling factor; and

modifying the second weight parameter by performing an operation selected from the group consisting of bit shifting, sign extending, zero extending and applying a scaling factor.

18. An apparatus for constructing a predicted picture, comprising:

means for modifying a first weight parameter associated with a region of a first frame to conform to a bit configuration;

means for modifying a second weight parameter associated with a region of a second frame to conform to the bit configuration;

means for calculating a first predicted component by applying the modified first weight parameter to the region of the first frame;

means for calculating a second predicted component by applying the modified second weight parameter to the region of the second frame; and

means for calculating a combined weighted prediction by combining the first predicted component and the second predicted component.

19. The apparatus of claim 18, further comprising:

means for choosing the bit configuration to accommodate a plurality of encoded bit configurations, wherein at least two of the plurality of encoded bit configurations have different numbers of bits.

20. The apparatus of claim 18, further comprising:

means for choosing the bit configuration to accommodate a plurality of encoded bit configurations, wherein at least one of the plurality of encoded bit configurations is signed and at least one of the plurality of encoded bit configurations is unsigned.

21. The apparatus of claim 18, further comprising:

means for locating the region of the first frame by using a motion vector.

22. The apparatus of claim 18, further comprising:

means for locating the region of the second frame by using a motion vector.

23. The apparatus of claim 18, further comprising:

means for locating the region of the first frame and locating the region of the second frame by using direct mode temporal interpolation of a decoded motion vector between the first frame and the second frame.

24. The apparatus of claim 18, further comprising:

means for locating the region of the first frame by identifying that the region of the first frame is a null region; and

means for calculating the first predicted component to be equal to zero.

25. The apparatus of claim 18, further comprising:

means for locating the region of the second frame by identifying that the region of the second frame is a null region; and

means for calculating the second predicted component to be equal to zero.

26. The apparatus of claim 18, wherein the first weight parameter and the second weight parameter are a same encoded bit configuration.

27. The apparatus of claim 18, further comprising:

means for identifying that the first weight parameter is zero; and

means for calculating the first predicted component to be equal to zero.

28. The apparatus of claim 18, further comprising:

means for identifying that the second weight parameter is zero; and

means for calculating the second predicted component to be equal to zero.

29. The apparatus of claim 18, wherein the first weight parameter and the second weight parameter are signed.

30. The apparatus of claim 18, further comprising:

means for normalizing the combined weighted prediction.

31. The apparatus of claim 18, further comprising:

means for normalizing the combined weighted prediction by bit shifting the combined weighted prediction a number of bits based on a base two logarithm of a denominator associated with the first weight parameter and the second weight parameter.

32. The apparatus of claim 18, further comprising:

means for receiving a first offset parameter associated with the region of the first frame;

means for receiving a second offset parameter associated with the region of the second frame; and

means for combining the first offset parameter and the second offset parameter with the combined weighted prediction.

33. The apparatus of claim 18, further comprising:

means for receiving a residual error associated with the combined weighted prediction; and

means for combining the residual error with the combined weighted prediction.

34. The apparatus of claim 18, further comprising:

means for receiving encoded video data representing the first weight parameter, the second weight parameter, the region of the first frame and the region of the second frame over a network.

35. The apparatus of claim 18, further comprising:

means for receiving encoded video data representing the first weight parameter, the second weight parameter, the region of the first frame and the region of the second frame over a wireless network.

36. The apparatus of claim 18, further comprising:

means for displaying the combined weighted prediction.

37. The apparatus of claim 18, further comprising:

means for modifying the first weight parameter by bit shifting; and

means for modifying the second weight parameter by bit shifting.

38. The apparatus of claim 18, further comprising:

means for modifying the first weight parameter by sign extending; and

means for modifying the second weight parameter by sign extending.

39. The apparatus of claim 18, further comprising:

means for modifying the first weight parameter by zero extending; and

means for modifying the second weight parameter by zero extending.

40. The apparatus of claim 18, further comprising:

means for modifying the first weight parameter by applying a scaling factor; and

means for modifying the second weight parameter by applying a scaling factor.

41. An electronic device for constructing a predicted picture, the electronic device configured to modify a first weight parameter associated with a region of a first frame to conform to a bit configuration, to modify a second weight parameter associated with a region of a second frame to conform to the bit configuration, to calculate a first predicted component by applying the modified first weight parameter to the region of the first frame, to calculate a second predicted component by applying the modified second weight parameter to the region of the second frame, and to calculate a combined weighted prediction by combining the first predicted component and the second predicted component.

42. The electronic device of claim 41, wherein the bit configuration accommodates a plurality of encoded bit configurations, wherein at least two of the plurality of encoded bit configurations have different numbers of bits.

43. The electronic device of claim 41, wherein the bit configuration accommodates a plurality of encoded bit configurations, wherein at least one of the plurality of encoded bit configurations is signed and at least one of the plurality of encoded bit configurations is unsigned.

44. The electronic device of claim 41, further configured to locate the region of the first frame using a motion vector.

45. The electronic device of claim 41, further configured to locate the region of the second frame using a motion vector.

46. The electronic device of claim 41, further configured to locate the region of the first frame and to locate the region of the second frame by using direct mode temporal interpolation of a decoded motion vector between the first frame and the second frame.

47. The electronic device of claim 41, further configured to locate the region of the first frame by identifying that the region of the first frame is a null region and to calculate the first predicted component to be equal to zero.

48. The electronic device of claim 41, further configured to locate the second region of the second frame by identifying that the region of the second frame is a null region and to calculate the second predicted component to be equal to zero.

49. The electronic device of claim 41, wherein the first weight parameter and the second weight parameter are a same encoded bit configuration.

50. The electronic device of claim 41, further configured to identify that the first weight parameter is zero and to calculate the first predicted component to be equal to zero.

51. The electronic device of claim 41, further configured to identify that the second weight parameter is zero and to calculate the second predicted component to be equal to zero.

52. The electronic device of claim 41, wherein the first weight parameter and the second weight parameter are signed.

53. The electronic device of claim 41, further configured to normalize the combined weighted prediction.

54. The electronic device of claim 41, further configured to normalize the combined weighted prediction by bit shifting the combined weighted prediction a number of bits based on a base two logarithm of a denominator associated with the first weight parameter and the second weight parameter.

55. The electronic device of claim 41, further configured to receive a first offset parameter associated with the region of the first frame and a second offset parameter associated with the region of the second frame, and to combine the first offset parameter and the second offset parameter with the combined weighted prediction.

56. The electronic device of claim 41, further configured to receive a residual error associated with the combined weighted prediction, and to combine the residual error with the combined weighted prediction.

57. The electronic device of claim 41, further configured to receive encoded video data representing the first weight parameter, the second weight parameter, the region of the first frame and the region of the second frame over a network.

58. The electronic device of claim 41, further configured to receive encoded video data representing the first weight parameter, the second weight parameter, the region of the first frame and the region of the second frame over a wireless network.

59. The electronic device of claim 41, further configured to display the combined weighted prediction.

60. The electronic device of claim 41, further configured to modify the first weight parameter with a bit shift and to modify the second weight parameter with a bit shift.

61. The electronic device of claim 41, further configured to modify the first weight parameter by sign extending and to modify the second weight parameter by sign extending.

62. The electronic device of claim 41, further configured to modify the first weight parameter by zero extending and to modify the second weight parameter by zero extending.

63. The electronic device of claim 41, further configured to modify the first weight parameter by applying a scaling factor and to modify the second weight parameter by applying a scaling factor.

64. A computer-readable embodying means for causing a computer to execute a method for constructing a predicted picture, the method comprising:

modifying a first weight parameter associated with a region of a first frame to conform to a bit configuration;

modifying a second weight parameter associated with a region of a second frame to conform to the bit configuration;

calculating a first predicted component by applying the modified first weight parameter to the region of the first frame;

calculating a second predicted component by applying the modified second weight parameter to the region of the second frame; and

calculating a combined weighted prediction by combining the first predicted component and the second predicted component.

65. The computer-readable medium of claim 64, further comprising:

choosing the bit configuration to accommodate a plurality of encoded bit configurations, wherein at least two of the plurality of encoded bit configurations have different numbers of bits.

66. The computer-readable medium of claim 64, further comprising:

choosing the bit configuration to accommodate a plurality of encoded bit configurations, wherein at least one of the plurality of encoded bit configurations is signed and at least one of the plurality of encoded bit configurations is unsigned.

67. At least one processor configured to implement a method, the method comprising:

modifying a first weight parameter associated with a region of a first frame to conform to a bit configuration;

modifying a second weight parameter associated with a region of a second frame to conform to the bit configuration;

calculating a first predicted component by applying the modified first weight parameter to the region of the first frame;

calculating a second predicted component by applying the modified second weight parameter to the region of the second frame; and

calculating a combined weighted prediction by combining the first predicted component and the second predicted component.