Motion wake identification and control mechanism

• US 20030161402A1
• Filed: 12/23/2002
• Published: 08/28/2003
• Est. Priority Date: 12/21/2001
• Status: Active Grant

• Current Assignee: Polycom Incorporated (HP Inc.)
• Original Assignee: Polycom Incorporated (HP Inc.)
• Inventors: Horowitz, Michael
• Granted Patent: US 8,780,970 B2
• Time in Patent Office: Days
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/503 involving temporal prediction adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 19/895 in combination with error concealment
• CPC Class Codes: H04N 7/148 Interfacing a video terminal to a particular transmission medium, e.g. ISDN

Abstract

The present invention provides a system and method for detecting macroblocks of a video frame that are located in one or more motion wake regions of the video frame. In one embodiment, a motion wake engine is configured to select a subset of macroblocks comprising non-peripherally located macroblocks selected to be inter-coded with motion vector magnitudes less than a predetermined motion vector threshold. Then, the motion wake engine identifies which macroblocks of the subset of macroblocks are located in first, second, third, or fourth motion wake regions of the video frame based upon a motion vector analysis of nearest neighbor macroblocks. In another embodiment of the invention, the motion wake engine applies error concealment/video improvement techniques to the identified macroblocks for video error concealment and for reducing visual artifacts associated with the motion wake regions.

Claims

1. A method for detecting motion wake regions of video frames, comprising the steps of:

receiving macroblocks of a video frame from a coding engine;

selecting a subset of macroblocks from the received macroblocks based upon macroblock properties; and

determining if a macroblock of the subset of macroblocks is located in any motion wake regions of the video frame based upon an analysis of motion vectors associated with nearest neighbor macroblocks.

2. The method of claim 1, wherein the step of selecting a subset of macroblocks further comprises the step of selecting non-peripherally located macroblocks with motion vector magnitudes less than a predetermined motion vector threshold that the coding engine has selected to inter-code.

3. The method of claim 1, wherein the coding engine performs motion estimation and mode decisions for each macroblock prior to the step of receiving macroblocks.

4. The method of claim 3, further comprising the step of generating one or more motion vectors for each macroblock.

5. The method of claim 2, wherein the predetermined motion vector threshold is one pixel.

6. The method of claim 1, wherein the macroblock of the subset of macroblocks is located in a first motion wake region of the video frame if at least two of the nearest neighbor macroblocks located in a positive x-direction with respect to the macroblock have significant displacements in the positive x-direction with respect to an x-displacement of the macroblock.

7. The method of claim 1, wherein the macroblock of the subset of macroblocks is located in a second motion wake region of the video frame if at least two of the nearest neighbor macroblocks located in a positive y-direction with respect to the macroblock have significant displacements in the positive y-direction with respect to a y-displacement of the macroblock.

8. The method of claim 1, wherein the macroblock of the subset of macroblocks is located in a third motion wake region of the video frame if at least two of the nearest neighbor macroblocks located in a negative x-direction with respect to the macroblock have significant displacements in the negative x-direction with respect to an x-displacement of the macroblock.

9. The method of claim 1, wherein the macroblock of the subset of macroblocks is located in a fourth motion wake region of the video frame if at least two of the nearest neighbor macroblocks located in a negative y-direction with respect to the macroblock have significant displacements in the negative y-direction with respect to a y-displacement of the macroblock.

10. The method of claim 1, wherein the step of determining further comprises the steps of:

summing x-components of motion vectors associated with a subset of the nearest neighbor macroblocks located in a positive x direction with respect to the macroblock of the subset of macroblocks to give a “

left”

SUM_L;

subtracting the “

left”

SUM_L from an x-component of a motion vector associated with each nearest neighbor macroblock of the subset of the nearest neighbor macroblocks to give first differences, and taking an absolute value of each of the first differences to give a first difference displacement for each of the nearest neighbor macroblocks of the subset of nearest neighbor macroblocks; and

determining that the macroblock of the subset of macroblocks is located in a first motion wake region of the video frame if the “

left”

SUM_L is greater than a predetermined “

left”

sum threshold and if all of the first difference displacements are less than a “

left”

difference displacement threshold.

11. The method of claim 1, wherein the step of determining further comprises the steps of:

summing y-components of motion vectors associated with a subset of the nearest neighbor macroblocks located in a positive y direction with respect to the macroblock of the subset of macroblocks to give an “

above”

SUM_A;

subtracting the “

above”

SUM_A from a y-component of a motion vector associated with each nearest neighbor macroblock of the subset of the nearest neighbor macroblocks to give second differences, and taking an absolute value of each of the second differences to give a second difference displacement for each of the nearest neighbor macroblocks of the subset of nearest neighbor macroblocks; and

determining that the macroblock of the subset of macroblocks is located in a second motion wake region of the video frame if the “

above”

SUM_A is greater than a predetermined “

above”

sum threshold and if all of the second difference displacements are less than an “

above”

difference displacement threshold.

12. The method of claim 1, wherein the step of determining further comprises the steps of:

summing x-components of motion vectors associated with a subset of the nearest neighbor macroblocks located in a negative x direction with respect to the macroblock of the subset of macroblocks to give a “

right”

SUM_R;

subtracting the “

right”

SUM_R from an x-component of a motion vector associated with each nearest neighbor macroblock of the subset of the nearest neighbor macroblocks to give third differences, and taking an absolute value of each of the third differences to give a third difference displacement for each of the nearest neighbor macroblocks of the subset of nearest neighbor macroblocks; and

determining that the macroblock of the subset of macroblocks is located in a third motion wake region of the video frame if the “

right”

SUM_R is less than a predetermined “

right”

sum threshold and if all of the third difference displacements are less than a “

right”

difference displacement threshold.

13. The method of claim 1, wherein the step of determining further comprises the steps of:

summing y-components of motion vectors associated with a subset of the nearest neighbor macroblocks located in a negative y direction with respect to the macroblock of the subset of macroblocks to give a “

below”

SUM_B;

subtracting the “

below”

SUM_B from a y-component of a motion vector associated with each nearest neighbor macroblock of the subset of the nearest neighbor macroblocks to give fourth differences, and taking an absolute value of each of the fourth differences to give a fourth difference displacement for each of the nearest neighbor macroblocks of the subset of nearest neighbor macroblocks; and

determining that the macroblock of the subset of macroblocks is located in a fourth motion wake region of the video frame if the “

below”

SUM_B is less than a predetermined “

below”

sum threshold and if all of the fourth difference displacements are less than a “

below”

difference displacement threshold.

14. The method of claim 1, further comprising the step of intra-coding macroblocks determined to be located in any motion wake regions of the video frame for video error concealment.

15. The method of claim 1, further comprising the step of reducing a quantization parameter (QP) associated with macroblocks determined to be located in any motion wake regions of the video frame for improving video frame quality.

16. The method of claim 1, further comprising the step of reducing a coding threshold associated with macroblocks determined to be located in any motion wake regions of the video frame for improving video frame quality.

17. An electronic-readable medium having embodied thereon a program, the program being executable by a machine to perform method steps for detecting video frame motion wake regions, the method steps comprising:

receiving macroblocks of a video frame from a coding engine;

selecting a subset of macroblocks from the received macroblocks based upon macroblock properties; and

determining if a macroblock of the subset of macroblocks is located in any motion wake regions of the video frame based upon an analysis of motion vectors associated with nearest neighbor macroblocks.

18. The electronic-readable medium of claim 17, wherein the step of selecting a subset of macroblocks further comprises the step of selecting non-peripherally located macroblocks with motion vector magnitudes less than a predetermined motion vector threshold that the coding engine has selected to inter-code.

19. The electronic-readable medium of claim 17, wherein the macroblock of the subset of macroblocks is located in a first motion wake region of the video frame if at least two of the nearest neighbor macroblocks located in a positive x-direction with respect to the macroblock have significant displacements in the positive x-direction with respect to an x-displacement of the macroblock.

20. The electronic-readable medium of claim 17, wherein the macroblock of the subset of macroblocks is located in a second motion wake region of the video frame if at least two of the nearest neighbor macroblocks located in a positive y-direction with respect to the macroblock have significant displacements in the positive y-direction with respect to a y-displacement of the macroblock.

21. The electronic-readable medium of claim 17, wherein the macroblock of the subset of macroblocks is located in a third motion wake region of the video frame if at least two of the nearest neighbor macroblocks located in a negative x-direction with respect to the macroblock have significant displacements in the negative x-direction with respect to an x-displacement of the macroblock.

22. The electronic-readable medium of claim 17, wherein the macroblock of the subset of macroblocks is located in a fourth motion wake region of the video frame if at least two of the nearest neighbor macroblocks located in a negative y-direction with respect to the macroblock have significant displacements in the negative y-direction with respect to a y-displacement of the macroblock.

23. The electronic-readable medium of claim 17, further comprising the step of intra-coding macroblocks determined to be located in any motion wake regions of the video frame for video error concealment.

24. The electronic-readable medium of claim 17, further comprising the step of reducing a quantization parameter (QP) associated with the macroblocks determined to be located in any motion wake regions of the video frame for improving video quality.

25. The electronic-readable medium of claim 17, further comprising the step of reducing a coding threshold associated with the macroblocks determined to be located in any motion wake regions of the video frame for improving video quality.

26. A system for video frame motion wake detection, comprising:

a coding engine configured to process each frame of a video signal to generate macroblocks, and encode the macroblocks as intra-coded and inter-coded macroblocks; and

a motion wake engine configured to detect which encoded macroblocks are located in motion wake regions of each frame.

27. The system of claim 26, wherein the motion wake engine is further configured to determine which non-peripherally located macroblocks with motion vector magnitudes less than a predetermined motion vector threshold that the coding engine has selected to inter-code are located in motion wake regions of each frame.

28. The system of claim 26, wherein the motion wake engine is further configured to determine whether a given encoded macroblock is located in a first motion wake region by determining if at least two nearest neighbor macroblocks located in a positive x-direction with respect to the given encoded macroblock have significant displacements in the positive x-direction with respect to an x-displacement of the given encoded macroblock.

29. The system of claim 26, wherein the motion wake engine is further configured to determine whether a given encoded macroblock is located in a second motion wake region by determining if at least two nearest neighbor macroblocks located in a positive y-direction with respect to the given encoded macroblock have significant displacements in the positive y-direction with respect to a y-displacement of the given encoded macroblock.

30. The system of claim 26, wherein the motion wake engine is further configured to determine whether a given encoded macroblock is located in a third motion wake region by determining if at least two nearest neighbor macroblocks located in a negative x-direction with respect to the given encoded macroblock have significant displacements in the negative x-direction with respect to an x-displacement of the given encoded macroblock.

31. The system of claim 26, wherein the motion wake engine is further configured to determine whether a given encoded macroblock is located in a fourth motion wake region by determining if at least two nearest neighbor macroblocks located in a negative y-direction with respect to the given encoded macroblock have significant displacements in the negative y-direction with respect to a y-displacement of the given encoded macroblock.

32. The system of claim 27, wherein the motion wake engine is further configured to intra-code macroblocks detected in one or more motion wake regions of each frame for video error concealment.

33. A system for detecting motion wake regions of video frames, comprising:

means for receiving macroblocks of a video frame from a coding engine;

means for selecting a subset of macroblocks from the received macroblocks based upon macroblock properties; and

means for determining if a macroblock of the subset of macroblocks is located in any motion wake regions of the video frame based upon an analysis of motion vectors associated with nearest neighbor macroblocks.