Motion vector block pattern coding and decoding

• US 7,599,438 B2
• Filed: 09/02/2004
• Issued: 10/06/2009
• Est. Priority Date: 09/07/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Lin, Chih-Lung, Srinivasan, Sridhar, Hsu, Pohsiang, Holcomb, Thomas W.
• Primary Examiner(s): DIEP, NHON THANH
• Application Number:
  US10/933,958
• Publication Number:
  US 20050053143A1
• Time in Patent Office: 1,860 Days
• Field of Search: 37524012-24016, 37524023-24026
• US Class Current: 375/240.23
• CPC Class Codes: H04N 19/102 characterised by the element, parameter or selection affected or controlled by the adaptive coding
• CPC Class Codes: H04N 19/109 among a plurality of temporal predictive coding modes
• CPC Class Codes: H04N 19/11 among a plurality of spatial predictive coding modes
• CPC Class Codes: H04N 19/112 according to a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/129 Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
• 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 19/146 Data rate or code amount at the encoder output
• 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 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/16 for a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/184 the unit being bits, e.g. of the compressed video stream
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/463 by compressing encoding parameters before transmission
• CPC Class Codes: H04N 19/51 : Motion estimation or motion compensation
• CPC Class Codes: H04N 19/52 : by predictive encoding
• CPC Class Codes: H04N 19/523 : with sub-pixel accuracy
• CPC Class Codes: H04N 19/593 : involving spatial prediction techniques
• CPC Class Codes: H04N 19/61 : in combination with predictive coding
• CPC Class Codes: H04N 19/63 : using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 19/70 : characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/82 : involving filtering within a prediction loop
• CPC Class Codes: H04N 19/86 : involving reduction of coding artifacts, e.g. of blockiness
• CPC Class Codes: H04N 19/93 : Run-length coding

Abstract

Techniques and tools for using motion vector block patterns in video encoding and decoding are described. In general, a motion vector block pattern signals the presence or absence of motion vector data for a macroblock with multiple motion vectors. For example, a video decoder decodes variable length codes that represent motion vector block patterns. Each motion vector block pattern has one bit per corresponding luminance motion vector of a macroblock with multiple luminance motion vectors, where the one bit indicates whether or not motion vector data for the corresponding luminance motion vector is signaled. A video encoder performs corresponding encoding.

Claims

1. A computer-implemented method for transforming video information using a computing device that implements a video encoder, the computing device comprising a processing unit and memory, the method comprising:

with the computing device that implements the video encoder;

determining a first variable length code that represents first information for a macroblock with plural luminance motion vectors, wherein the first information includes one motion vector data presence indicator per luminance motion vector of the macroblock, wherein each of the motion vector data presence indicators is represented by a corresponding bit in a bit field, wherein a bit value of zero indicates that no motion vector data is signaled for a corresponding one of the plural luminance motion vectors and a bit value of one indicates that motion vector data is signaled for the corresponding one of the plural luminance motion vectors;

signaling, in a bitstream, the first variable length code;

determining a second variable length code that represents second information for the macroblock, wherein the second information includes plural transform coefficient data presence indicators for plural blocks of the macroblock; and

signaling, in the bitstream, the second variable length code.

2. The method of claim 1 further comprising:

with the computing device that implements the video encoder;

signaling, in the bitstream, motion vector data for each of the plural luminance motion vectors for which the motion vector data is indicated to be present by the first information.

3. The method of claim 2 wherein the motion vector data includes motion vector differential information and/or a predictor polarity selection.

4. The method of claim 1 wherein the macroblock has four luminance motion vectors (corresponding to four luminance blocks), and wherein the first information consists of four motion vector data presence indicators.

5. The method of claim 1 wherein the macroblock has two luminance motion vectors, and wherein the first information consists of two motion vector data presence indicators.

6. The method of claim 1 further comprising signaling, in the bitstream, a table selection code indicating which of plural variable length code tables to use to determine the first variable length code.

7. The method of claim 6 wherein the table selection code is signaled at picture level or at slice level.

8. The method of claim 6 wherein the table selection code is a fixed length code.

9. A computer-implemented method for transforming video information using a computing device that implements a video encoder, the computing device comprising a processing unit and memory, the method comprising:

with the computing device that implements the video encoder;

for a macroblock with a first number of luminance motion vectors, wherein the first number is greater than one, determining a motion vector block pattern that consists of a second number of bits, wherein the second number is equal to the first number, and wherein each of the bits of the motion vector block pattern indicates whether or not a corresponding one of the luminance motion vectors has associated motion vector data signaled in a bitstream, wherein a bit value of zero indicates that no motion vector data is signaled for the corresponding one of the luminance motion vectors and a bit value of one indicates that motion vector data is signaled for the corresponding one of the luminance motion vectors;

signaling, in the bitstream, the motion vector block pattern, wherein the motion vector block pattern is signaled with a variable length code; and

signaling, in the bitstream, associated motion vector data for each of the luminance motion vectors for which the associated motion vector data is indicated to be signaled in the bitstream.

10. The method of claim 9 further comprising:

with the computing device that implements the video encoder;

determining a coded block pattern that indicates which of plural blocks of the macroblock have associated transform coefficient data signaled in the bitstream.

11. The method of claim 9 wherein the associated motion vector data includes motion vector differential information.

12. The method of claim 11 wherein the associated motion vector data further includes a predictor polarity selection.

13. The method of claim 9 wherein the macroblock has four luminance motion vectors for four luminance blocks of the macroblock, respectively.

14. The method of claim 9 wherein the macroblock has two luminance motion vectors for top and bottom fields of the macroblock, respectively.

15. The method of claim 9 wherein the macroblock has four luminance motion vectors for left and right halves of top and bottom fields of the macroblock, respectively.

16. The method of claim 9 further comprising signaling, in the bitstream, a table selection code indicating which of plural variable length code tables to use in determining the motion vector block pattern.

17. A video decoder comprising:

means for decoding plural variable length codes that represent plural motion vector block patterns, wherein each of the plural motion vector block patterns has one bit per corresponding luminance motion vector of a macroblock with multiple luminance motion vectors, the one bit indicating whether or not motion vector data for the corresponding luminance motion vector is signaled, wherein a bit value of zero indicates that no motion vector data is signaled for the corresponding luminance motion vector and a bit value of one indicates that motion vector data is signaled for the corresponding luminance motion vector; and

means for decoding motion vector data.

18. The decoder of claim 17 further comprising means for selecting a variable length code table from among plural available variable length code tables for decoding the plural variable length codes that represent the plural motion vector block patterns.

19. A computer-implemented method for transforming encoded video information using a computing device that implements a video decoder, the computing device comprising a processing unit and memory, the method comprising:

with the computing device that implements the video decoder;

receiving, in a bitstream, a first variable length code;

decoding the first variable length code, wherein the first variable length code represents first information for a macroblock with plural luminance motion vectors, wherein the first information includes one motion vector data presence indicator per luminance motion vector of the macroblock, wherein each of the motion vector data presence indicators is represented by a corresponding bit in a bit field, wherein a bit value of zero indicates that no motion vector data is signaled for a corresponding one of the plural luminance motion vectors and a bit value of one indicates that motion vector data is signaled for the corresponding one of the plural luminance motion vectors;

receiving, in the bitstream, a second variable length code; and

decoding the second variable length code, wherein the second variable length code represents second information for the macroblock, wherein the second information includes plural transform coefficient data presence indicators for plural blocks of the macroblock.

20. The method of claim 19 further comprising:

with the computing device that implements the video decoder;

receiving, in the bitstream, motion vector data for each of the plural luminance motion vectors for which the motion vector data is indicated to be present by the first information.

21. The method of claim 20 wherein the motion vector data includes motion vector differential information and/or a predictor polarity selection.

22. The method of claim 19 wherein the macroblock has four luminance motion vectors (corresponding to four luminance blocks), and wherein the first information consists of four motion vector data presence indicators.

23. The method of claim 19 wherein the macroblock has two luminance motion vectors, and wherein the first information consists of two motion vector data presence indicators.

24. The method of claim 19 further comprising receiving, in the bitstream, a table selection code indicating which of plural variable length code tables to use to decode the first variable length code.

25. The method of claim 24 wherein the table selection code is signaled at picture level or at slice level.

26. The method of claim 24 wherein the table selection code is a fixed length code.

27. A computer-implemented method for transforming encoded video information using a computing device that implements a video decoder, the computing device comprising a processing unit and memory, the method comprising:

with the computing device that implements the video decoder;

for a macroblock with a first number of luminance motion vectors, wherein the first number is greater than one, receiving, in a bitstream, a motion vector block pattern that consists of a second number of bits, wherein the second number is equal to the first number, and wherein each of the bits of the motion vector block pattern indicates whether or not a corresponding one of the luminance motion vectors has associated motion vector data signaled in the bitstream, wherein a bit value of zero indicates that no motion vector data is signaled for the corresponding one of the luminance motion vectors and a bit value of one indicates that motion vector data is signaled for the corresponding one of the luminance motion vectors, and wherein the motion vector block pattern is received as a variable length code; and

receiving, in the bitstream, associated motion vector data for each of the luminance motion vectors for which the associated motion vector data is indicated to be signaled in the bitstream.

28. The method of claim 27 further comprising:

with the computing device that implements the video decoder;

receiving, in the bitstream, a coded block pattern that indicates which of plural blocks of the macroblock have associated transform coefficient data signaled in the bitstream.

29. The method of claim 27 wherein the associated motion vector data includes motion vector differential information.

30. The method of claim 29 wherein the associated motion vector data further includes a predictor polarity selection.

31. The method of claim 27 wherein the macroblock has four luminance motion vectors for four luminance blocks of the macroblock, respectively.

32. The method of claim 27 wherein the macroblock has two luminance motion vectors for top and bottom fields of the macroblock, respectively.

33. The method of claim 27 wherein the macroblock has four luminance motion vectors for left and right halves of top and bottom fields of the macroblock, respectively.

34. The method of claim 27 further comprising receiving, in the bitstream, a table selection code indicating which of plural variable length code tables to use in decoding the motion vector block pattern.