MOTION VECTOR CODING FOR VIDEO CODING

• US 20180091816A1
• Filed: 09/28/2017
• Published: 03/29/2018
• Est. Priority Date: 09/29/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chien, Wei-Jung, Chen, Jianle, Zhang, Li, Karczewicz, Marta
• Granted Patent: US 10,462,462 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/52 by predictive encoding
• CPC Class Codes: H04N 19/521 for estimating the reliability of the determined motion vectors or motion vector field, e.g. for smoothing the motion vector field or for correcting motion vectors
• CPC Class Codes: H04N 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

Coding a motion vector difference (MVD) during an inter-prediction process. Example techniques may include determining a particular coding and/or signaling method for an MVD from among two or more MVD coding and/or signaling techniques. A video coder (e.g., a video encoder and/or a video decoder) may determine a particular MVD coding and/or signaling technique based on characteristics of video data or coding methods, including MV precision, Picture Order Count (POC) difference, or any other already coded/decoded information of a block of video data.

Claims

1. A method of decoding video data, the method comprising:

receiving an encoded block of video data;

receiving one or more syntax elements indicating a motion vector difference (MVD) associated with the encoded block of video data;

determining an MVD coding technique from two or more MVD coding techniques;

decoding the one or more syntax elements indicating the MVD using the determined MVD coding technique; and

decoding the encoded block of video data using the decoded MVD.

2. The method of claim 1, wherein the two or more MVD coding techniques comprise two or more binarization techniques for the one or more syntax elements indicating the MVD.

3. The method of claim 2, wherein the two or more binarization techniques include at least one of exponential-Golomb coding, unary coding, or fixed length coding.

4. The method of claim 3, wherein the two or more binarization techniques include Kth order exponential-Golomb coding, and wherein determining the MVD coding technique comprises:

determining a value of K for the Kth order exponential-Golomb coding used for binarization based on characteristics of one or more of a slice, tile, or picture.

5. The method of claim 2, wherein determining the MVD coding technique comprises determining a binarization technique from the two or more binarization techniques based on a motion vector precision or a picture order count (POC) distance between the encoded block of video data and a reference picture associated with the encoded block of video data.

6. The method of claim 5, the method further comprising:

determining that the motion vector precision for the encoded block of video data is a one-quarter pixel precision, and wherein

determining the MVD coding technique comprises determining that a syntax element indicating an absolute value of the MVD minus two is binarized with an exponential Golomb code with a parameter of 1.

7. The method of claim 5, the method further comprising:

determining that the motion vector precision for the encoded block of video data is an integer pixel precision, and wherein

determining the MVD coding technique comprises determining that a syntax element indicating an absolute value of the MVD minus two is binarized with an exponential Golomb code with a parameter of 2.

8. The method of claim 2, wherein determining the MVD coding technique comprises:

determining a binarization technique from the two or more binarization techniques based on one or more of a block size of the encoded block of video data, a motion vector precision used for the MVD, a motion model, an inter prediction direction, a reference picture, a picture order count difference between the encoded block of video data and the reference picture, a motion vector of a neighboring block, an MVD of a neighboring block, intra/inter mode decision of neighboring blocks, or a motion predictor characteristic.

9. The method of claim 1, wherein the two or more MVD coding techniques comprise two or more sets of contexts used to entropy code the one or more syntax elements indicating the MVD.

10. The method of claim 9, wherein determining the MVD coding technique comprises:

determining a set of contexts from the two or more sets of contexts based on one or more of a block size of the encoded block of video data, a motion vector precision used for the MVD, a motion model, an inter prediction direction, a reference picture, a picture order count difference between the encoded block of video data and the reference picture, a motion vector of a neighboring block, an MVD of a neighboring block, intra/inter mode decision of neighboring blocks, or a motion predictor characteristic.

11. The method of claim 9, wherein determining the MVD coding technique comprises determining the set of contexts from the two or more sets of contexts based on a motion vector precision or a picture order count (POC) distance between the encoded block of video data and a reference picture associated with the encoded block of video data.

12. The method of claim 1, wherein decoding the one or more syntax elements indicating the MVD using the determined MVD coding technique comprises:

decoding the one or more syntax elements indicating the MVD using the determined MVD coding technique in two or more parts.

13. The method of claim 12, wherein decoding the one or more syntax elements indicating the MVD using the determined MVD coding technique in two or more parts comprises:

decoding a first syntax element indicating whether a horizontal component of the MVD is zero; and

decoding a second syntax element indicating whether a vertical component of the MVD is zero.

14. An apparatus configured to decode video data, the apparatus comprising:

a memory configured to store an encoded block of video data; and

one or more processors configured to;

receive the encoded block of video data;

receive one or more syntax elements indicating a motion vector difference (MVD) associated with the encoded block of video data;

determine an MVD coding technique from two or more MVD coding techniques;

decode the one or more syntax elements indicating the MVD using the determined MVD coding technique; and

decode the encoded block of video data using the decoded MVD.

15. The apparatus of claim 14, wherein the two or more MVD coding techniques comprise two or more binarization techniques for the one or more syntax elements indicating the MVD.

16. The apparatus of claim 15, wherein the two or more binarization techniques include at least one of exponential-Golomb coding, unary coding, or fixed length coding.

17. The apparatus of claim 16, wherein the two or more binarization techniques include Kth order exponential-Golomb coding, and wherein to determine the MVD coding technique, the one or more processors are further configured to:

determine a value of K for the Kth order exponential-Golomb coding used for binarization based on characteristics of one or more of a slice, tile, or picture.

18. The apparatus of claim 15, wherein to determine the MVD coding technique, the one or more processors are further configured to determine a binarization technique from the two or more binarization techniques based on a motion vector precision or a picture order count (POC) distance between the encoded block of video data and a reference picture associated with the encoded block of video data.

19. The apparatus of claim 18, wherein the one or more processors are further configured to:

determine that the motion vector precision for the encoded block of video data is a one-quarter pixel precision; and

determine that a syntax element indicating an absolute value of the MVD minus two is binarized with an exponential Golomb code with a parameter of 1.

20. The apparatus of claim 18, wherein the one or more processors are further configured to:

determine that the motion vector precision for the encoded block of video data is an integer pixel precision; and

determine that a syntax element indicating an absolute value of the MVD minus two is binarized with an exponential Golomb code with a parameter of 2.

21. The apparatus of claim 15, wherein to determine the MVD coding technique, the one or more processors are further configured to:

determine a binarization technique from the two or more binarization techniques based on one or more of a block size of the encoded block of video data, a motion vector precision used for the MVD, a motion model, an inter prediction direction, a reference picture, a picture order count difference between the encoded block of video data and the reference picture, a motion vector of a neighboring block, an MVD of a neighboring block, intra/inter mode decision of neighboring blocks, or a motion predictor characteristic.

22. The apparatus of claim 14, wherein the two or more MVD coding techniques comprise two or more sets of contexts used to entropy code the one or more syntax elements indicating the MVD.

23. The apparatus of claim 22, wherein to determine the MVD coding technique, the one or more processors are further configured to:

determine a set of contexts from the two or more sets of contexts based on one or more of a block size of the encoded block of video data, a motion vector precision used for the MVD, a motion model, an inter prediction direction, a reference picture, a picture order count difference between the encoded block of video data and the reference picture, a motion vector of a neighboring block, an MVD of a neighboring block, intra/inter mode decision of neighboring blocks, or a motion predictor characteristic.

24. The apparatus of claim 22, wherein to determine the MVD coding technique, the one or more processors are further configured to determine the set of contexts from the two or more sets of contexts based on a motion vector precision or a picture order count (POC) distance between the encoded block of video data and a reference picture associated with the encoded block of video data.

25. The apparatus of claim 14, wherein to decode the one or more syntax elements indicating the MVD using the determined MVD coding technique, the one or more processors are further configured to:

decode the one or more syntax elements indicating the MVD using the determined MVD coding technique in two or more parts.

26. The apparatus of claim 25, wherein to decode the one or more syntax elements indicating the MVD using the determined MVD coding technique in two or more parts, the one or more processors are further configured to:

decode a first syntax element indicating whether a horizontal component of the MVD is zero; and

decode a second syntax element indicating whether a vertical component of the MVD is zero.

27. The apparatus of claim 14, wherein the apparatus comprises a wireless communication device, further comprising a receiver configured to receive the encoded block of video data.

28. The apparatus of claim 27, wherein the wireless communication device comprises a telephone handset and wherein the receiver is configured to demodulate, according to a wireless communication standard, a signal comprising the encoded block of video data.

29. The apparatus of claim 14, further comprising:

a display configured to output a picture including the decoded block of video data.

30. An apparatus configured to decode video data, the apparatus comprising:

means for receiving an encoded block of video data;

means for receiving one or more syntax elements indicating a motion vector difference (MVD) associated with the encoded block of video data;

means for determining an MVD coding technique from two or more MVD coding techniques;

means for decoding the one or more syntax elements indicating the MVD using the determined MVD coding technique; and

means for decoding the encoded block of video data using the decoded MVD.

31. A computer-readable storage medium storing instructions that, when executed, causes one or more processors of a device configured to decode video data to:

receive the encoded block of video data;

receive one or more syntax elements indicating a motion vector difference (MVD) associated with the encoded block of video data;

determine an MVD coding technique from two or more MVD coding techniques;

decode the one or more syntax elements indicating the MVD using the determined MVD coding technique; and

decode the encoded block of video data using the decoded MVD.

32. A method of encoding video data, the method comprising:

encoding a block of video data according to an inter-prediction mode;

determining a motion vector difference (MVD) associated with the block of video data;

determining an MVD coding technique from two or more MVD coding techniques; and

encoding one or more syntax elements indicating the MVD using the determined MVD coding technique.

33. The method of claim 32, wherein the two or more MVD coding techniques comprise two or more binarization techniques for the one or more syntax elements indicating the MVD.

34. The method of claim 33, wherein the two or more binarization techniques include at least one of exponential-Golomb coding, unary coding, or fixed length coding.

35. The method of claim 34, wherein the two or more binarization techniques include Kth order exponential-Golomb coding, and wherein determining the MVD coding technique comprises:

determining a value of K for the Kth order exponential-Golomb coding used for binarization based on characteristics of one or more of a slice, tile, or picture.

36. The method of claim 33, wherein determining the MVD coding technique comprises determining a binarization technique from the two or more binarization techniques based on a motion vector precision or a picture order count (POC) distance between the encoded block of video data and a reference picture associated with the encoded block of video data.

37. The method of claim 36, the method further comprising:

determining that the motion vector precision for the block of video data is a one-quarter pixel precision, and wherein

determining the MVD coding technique comprises determining that a syntax element indicating an absolute value of the MVD minus two is binarized with an exponential Golomb code with a parameter of 1.

38. The method of claim 36, the method further comprising:

determining that the motion vector precision for the encoded block of video data is an integer pixel precision, and wherein

determining the MVD coding technique comprises determining that a syntax element indicating an absolute value of the MVD minus two is binarized with an exponential Golomb code with a parameter of 2.

39. The method of claim 33, wherein determining the MVD coding technique comprises:

determining a binarization technique from the two or more binarization techniques based on one or more of a block size of the encoded block of video data, a motion vector precision used for the MVD, a motion model, an inter prediction direction, a reference picture, a picture order count difference between the encoded block of video data and the reference picture, a motion vector of a neighboring block, an MVD of a neighboring block, intra/inter mode decision of neighboring blocks, or a motion predictor characteristic.

40. The method of claim 32, wherein the two or more MVD coding techniques comprise two or more sets of contexts used to entropy code the one or more syntax elements indicating the MVD.

41. The method of claim 40, wherein determining the MVD coding technique comprises:

determining a set of contexts from the two or more sets of contexts based on one or more of a block size of the encoded block of video data, a motion vector precision used for the MVD, a motion model, an inter prediction direction, a reference picture, a picture order count difference between the encoded block of video data and the reference picture, a motion vector of a neighboring block, an MVD of a neighboring block, intra/inter mode decision of neighboring blocks, or a motion predictor characteristic.

42. The method of claim 40, wherein determining the MVD coding technique comprises determining the set of contexts from the two or more sets of contexts based on a motion vector precision or a picture order count (POC) distance between the encoded block of video data and a reference picture associated with the encoded block of video data.

43. The method of claim 32, wherein encoding the one or more syntax elements indicating the MVD using the determined MVD coding technique comprises:

encoding the one or more syntax elements indicating the MVD using the determined MVD coding technique in two or more parts.

44. The method of claim 43, wherein encoding the one or more syntax elements indicating the MVD using the determined MVD coding technique in two or more parts comprises:

encoding a first syntax element indicating whether a horizontal component of the MVD is zero; and

encoding a second syntax element indicating whether a vertical component of the MVD is zero.

45. An apparatus configured to encode video data, the apparatus comprising:

a memory configured to store a block of video data; and

one or more processors configured to;

encode the block of video data according to an inter-prediction mode;

determine a motion vector difference (MVD) associated with the block of video data;

determine an MVD coding technique from two or more MVD coding techniques; and

encode one or more syntax elements indicating the MVD using the determined MVD coding technique.

46. The apparatus of claim 45, further comprising:

a camera configured to capture a picture including the block of video data.