METHOD AND APPARATUS FOR ENCODING AND DECODING MOTION VECTOR

• US 20110170602A1
• Filed: 01/14/2011
• Published: 07/14/2011
• Est. Priority Date: 01/14/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: MIN, Jung-hye, HAN, Woo-jin, LEE, Tammy
• Granted Patent: US 8,995,529 B2
• Time in Patent Office: Days
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/103 Selection of coding mode or of prediction mode
• 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 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/33 in the spatial domain
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/513 Processing of motion vectors
• CPC Class Codes: H04N 19/52 by predictive encoding
• 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 19/96 Tree coding, e.g. quad-tree coding

Abstract

Provided are methods and apparatuses for encoding and decoding a motion vector. The method of encoding a motion vector includes: selecting a mode from among a first mode in which information indicating a motion vector predictor of at least one motion vector predictor is encoded and a second mode in which information indicating generation of a motion vector predictor based on pixels included in a previously encoded area adjacent to a current block is encoded; determining a motion vector predictor of the current block according to the selected mode and encoding information about the motion vector predictor of the current block; and encoding a difference vector between a motion vector of the current block and the motion vector predictor of the current block.

Claims

1. A method of encoding a motion vector, the method comprising:

selecting, from among a first mode and a second mode, the first mode in which information indicating a motion vector predictor of at least one motion vector predictor is encoded or the second mode in which information indicating generation of a motion vector predictor based on pixels included in a previously encoded area adjacent to a current block is encoded;

determining a motion vector predictor of the current block according to the selected mode and encoding information about the motion vector predictor of the current block; and

encoding a difference vector between a motion vector of the current block and the motion vector predictor of the current block,

wherein the second mode is a mode in which information indicating generation of the motion vector predictor by setting a range within which the motion vector predictor is to be searched based on the at least one motion vector predictor and by searching within the search range by using pixels included in the previously encoded area, is encoded.

2. The method of claim 1, wherein the selecting the first mode or the second mode comprises selecting the first mode or the second mode based on a depth indicating a degree of decreasing from a size of a maximum coding unit of a current picture or slice to a size of the current block.

3. The method of claim 1, wherein the selecting the first mode or the second mode comprises selecting the first mode or the second mode in a unit of a current picture comprising the current block or in a unit of a slice comprising the current block.

4. The method of claim 1, wherein the selecting the first mode or the second mode comprises selecting the first mode or the second mode based on whether the current block is encoded in a skip mode.

5. The method of claim 1, wherein the at least one motion vector predictor comprises a first motion vector of a block adjacent to a left side of the current block, a second motion vector of a block adjacent to an upper side of the current block, and a third motion vector of a block adjacent to an upper-right side of the current block.

6. The method of claim 5, wherein the at least one motion vector predictor further comprises a median value of the first motion vector, the second motion vector, and the third motion vector.

7. The method of claim 5, wherein the at least one motion vector predictor further comprises a motion vector predictor generated based on a motion vector of a block co-located with the current block in a reference picture and a temporal distance between the reference picture and a current picture.

8. The method of claim 7, wherein the encoding the information about the motion vector predictor of the current block comprises encoding information indicating whether the block co-located with the current block is a block of a picture temporally preceding the current picture or a block of a picture temporally following the current picture.

9. The method of claim 8, wherein the information indicating whether the block co-located with the current block is the block of the picture temporally preceding the current picture or the block of the picture temporally following the current picture is inserted into a header of a slice comprising the current block.

27. A computer readable recording medium having recorded thereon a computer program for executing the method of claim 1.

10. An apparatus for encoding a motion vector, the apparatus comprising:

a prediction unit which selects, from among a first mode and a second, the first mode in which information indicating a motion vector predictor of at least one motion vector predictor is encoded or the second mode in which information indicating generation of a motion vector predictor based on pixels included in a previously encoded area adjacent to a current block is encoded;

a first encoder which determines a motion vector predictor of the current block according to the selected mode and encodes information about the motion vector predictor of the current block; and

a second encoder which encodes a difference vector between a motion vector of the current block and the motion vector predictor of the current block,

wherein the second mode is a mode in which information indicating generation of the motion vector predictor by setting a range within which the motion vector predictor is to be searched based on the at least one motion vector predictor and by searching within the search range by using pixels included in the previously encoded area, is encoded.

11. The apparatus of claim 10, wherein the prediction unit selects the first mode or the second mode based on a depth indicating a degree of decreasing from a size of a maximum coding unit of a current picture or slice to a size of the current block.

12. The apparatus of claim 10, wherein the at least one motion vector predictor comprises a motion vector predictor generated based on a motion vector of a block co-located with the current block in a reference picture and a temporal distance between the reference picture and a current picture.

13. The apparatus of claim 12, wherein the first encoder encodes information indicating whether the block co-located with the current block is a block of a picture temporally preceding the current picture or a block of a picture temporally following the current picture.

14. A method of decoding a motion vector, the method comprising:

decoding information about a motion vector predictor of a current block encoded according to a mode selected from among a first mode and a second mode;

decoding a difference vector between a motion vector of the current block and the motion vector predictor of the current block;

generating the motion vector predictor of the current block based on the decoded information about the motion vector predictor of the current block; and

restoring the motion vector of the current block based on the generated motion vector predictor and the decoded difference vector,

wherein the first mode is a mode in which information indicating the motion vector predictor of at least one motion vector predictor is encoded and the second mode is a mode in which information indicating generation of the motion vector predictor by setting a range within which the motion vector predictor is to be searched based on the at least one motion vector predictor and by searching within the search range by using pixels included in a previously encoded area adjacent to the current block, is encoded.

15. The method of claim 14, wherein the mode selected from among the first mode and the second mode is a mode selected based on a depth indicating a degree of decreasing in phases from a size of a maximum coding unit of a current picture or slice to a size of the current block.

16. The method of claim 14, wherein the mode selected from among the first mode and the second mode is a mode selected in a unit of a current picture comprising the current block or a unit of a slice comprising the current block.

17. The method of claim 14, wherein the mode selected from among the first mode and the second mode is a mode selected based on whether the current block is encoded in a skip mode.

18. The method of claim 14, wherein the at least one motion vector predictor comprises a first motion vector of a block adjacent to a left side of the current block, a second motion vector of a block adjacent to an upper side of the current block, and a third motion vector of a block adjacent to an upper-right side of the current block.

19. The method of claim 18, wherein the at least one motion vector predictor further comprises a median value of the first motion vector, the second motion vector, and the third motion vector.

20. The method of claim 18, wherein the at least one motion vector predictor further comprises a motion vector predictor generated based on a motion vector of a block co-located with the current block in a reference picture and a temporal distance between the reference picture and a current picture.

21. The method of claim 20, wherein the decoding the information about the motion vector predictor of the current block comprises decoding information indicating whether the block co-located with the current block is a block of a picture temporally preceding the current picture or a block of a picture temporally following the current picture.

22. The method of claim 21, wherein the information indicating whether the block co-located with the current block is the block of the picture temporally preceding the current picture or the block of the picture temporally following the current picture is inserted into a header of a slice comprising the current block.

28. A computer readable recording medium having recorded thereon a computer program for executing the method of claim 14.

23. An apparatus for decoding a motion vector, the apparatus comprising:

a first decoder which decodes information about a motion vector predictor of a current block encoded according to a mode selected from among a first mode and a second mode;

a second decoder which decodes a difference vector between a motion vector of the current block and the motion vector predictor of the current block;

a prediction unit which generates the motion vector predictor of the current block based on the decoded information about the motion vector predictor of the current block; and

a motion vector restorer which restores the motion vector of the current block based on the generated motion vector predictor and the decoded difference vector,

wherein the first mode is a mode in which information indicating the motion vector predictor of at least one motion vector predictor is encoded and the second mode is a mode in which information indicating generation of the motion vector predictor by setting a range within which the motion vector predictor is to be searched based on the at least one motion vector predictor and by searching within the search range by using pixels included in a previously encoded area adjacent to the current block, is encoded.

24. The apparatus of claim 23, wherein the mode selected from among the first mode and the second mode is a mode selected based on a depth indicating a degree of decreasing in phases from a size of a maximum coding unit of a current picture or slice to a size of the current block.

25. The apparatus of claim 23, wherein the at least one motion vector predictor comprises a motion vector predictor generated based on a motion vector of a block co-located with the current block in a reference picture and a temporal distance between the reference picture and a current picture.

26. The apparatus of claim 25, wherein the first decoder decodes information indicating whether the block co-located with the current block is a block of a picture temporally preceding the current picture or a block of a picture temporally following the current picture.