ADAPTIVE MOTION VECTOR RESOLUTION SIGNALING FOR VIDEO CODING

• US 20150195562A1
• Filed: 01/08/2015
• Published: 07/09/2015
• Est. Priority Date: 01/09/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Li, Xiang, Sole Rojals, Joel, Karczewicz, Marta, Zhang, Li, Chen, Jianle, Liu, Hongbin
• Granted Patent: US 10,531,116 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• 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 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 19/53 Multi-resolution motion estimation; Hierarchical motion estimation
• CPC Class Codes: H04N 19/533 Motion estimation using multistep search, e.g. 2D-log search or one-at-a-time search [OTS]
• CPC Class Codes: H04N 19/56 Motion estimation with initialisation of the vector search, e.g. estimating a good candidate to initiate a search

Abstract

A device for decoding video data includes a memory configured to store video data and a video decoder comprising one or more processors configured to adaptively select motion vector precision for motion vectors used to encode blocks of video data.

Claims

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

determining that a coding mode for a first block is merge mode;

determining that a motion vector precision for the first block is integer pixel precision;

constructing a merge candidate list for the first block, wherein constructing the merge candidate list comprises adding a fractional precision motion vector candidate to the merge candidate list;

selecting the fractional precision motion vector candidate to decode the first block;

in response to selecting the fractional precision motion vector, rounding the fractional precision motion vector candidate to determine an integer pixel precision motion vector for the first block;

locating a reference block for the first block using the integer pixel precision motion vector; and

decoding the first block based on the reference block.

2. The method of claim 1, wherein determining the motion vector precision for the first block is integer pixel precision comprises receiving in the encoded video data an indication that the motion vector precision for the first block is integer pixel precision.

3. The method of claim 1, wherein the merge mode comprises a skip mode.

4. The method of claim 1, further comprising:

determining that a coding mode for a second block is other than a merge mode;

determining that a motion vector precision for the second block is integer pixel precision;

determining a fractional precision motion vector predictor for the second block;

rounding the fractional precision motion vector predictor to determine an integer pixel precision motion vector predictor for the second block;

determining a motion vector difference for the second block, wherein the motion vector difference comprises an integer pixel precision difference;

determining an integer pixel precision motion vector for the second block based on the integer pixel precision motion vector predictor and the motion vector difference; and

locating a reference block for the second block using the integer pixel precision motion vector.

5. The method of claim 4, wherein determining the fractional precision motion vector predictor for the second block comprises:

constructing an AMVP candidate list for the second block, wherein the AMVP candidate list comprises a second fractional precision motion vector candidate;

selecting the second fractional precision motion vector candidate as the fractional precision motion vector predictor for the second block.

6. The method of claim 5, further comprising:

adding the integer precision motion vector to a candidate list for a second block.

7. The method of claim 1, further comprising:

adding the fractional precision motion vector candidate to a candidate list for a second block.

8. The method of claim 7, wherein the candidate list for the second block comprises an AMVP candidate list.

99. The method of claim 1, further comprising:

for a second block of video data, determining a motion vector difference value;

in response to the motion vector difference value being equal to zero, determining that a motion vector for the second block has sub-pixel motion vector precision.

100. The method of claim 1, further comprising:

determining a motion vector difference precision for a second block is integer pixel precision;

constructing a candidate list of motion vector predictors for the second block, wherein the candidate list comprises a fractional precision motion vector candidate;

selecting from the candidate list for the second block the fractional precision motion vector candidate;

determining a fractional pixel precision motion vector based on the fractional precision motion vector candidate and the integer pixel precision motion vector difference;

locating a second reference block for the second block using the fractional pixel precision motion vector.

101. The method of claim 1, the method comprising:

receiving, for a second block of video data, first motion vector precision information;

in response to a third block of video data meeting a condition, determining third motion vector information to correspond to a default precision.

102. The method of claim 101, wherein the default precision comprises fractional precision.

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

determining that a motion vector precision for a first block is integer pixel precision;

constructing a merge candidate list for the first block, wherein the merge candidate list comprises a fractional precision motion vector candidate;

selecting the fractional precision motion vector candidate to encode the first block;

to code the first block using a merge mode, rounding the fractional precision motion vector candidate to determine an integer pixel precision motion vector for the first block; and

locating a reference block for the first block using the integer pixel precision motion vector.

10. The method of claim 9, further comprising:

generating for inclusion in the encoded video data, an indication that a motion vector precision for the first block is integer pixel precision.

11. The method of claim 9, wherein the merge mode comprises a skip mode.

12. The method of claim 9, further comprising:

determining that a motion vector precision for a second block is integer pixel precision;

to code the second block in a mode other than the merge mode, determining a fractional precision motion vector predictor for the second block;

rounding the fractional precision motion vector predictor to determine an integer pixel precision motion vector predictor for the second block;

determining a motion vector difference for the second block, wherein the motion vector difference comprises an integer pixel precision difference;

determining an integer pixel precision motion vector for the second block based on the integer pixel precision motion vector predictor and the motion vector difference; and

locating a reference block for the second block using the integer pixel precision motion vector;

encode the first block based on the reference block.

13. The method of claim 12, wherein determining the fractional precision motion vector predictor for the second block comprises:

constructing an AMVP candidate list for the second block, wherein the AMVP candidate list comprises a second fractional precision motion vector candidate;

selecting the second fractional precision motion vector candidate as the fractional precision motion vector predictor for the second block.

14. The method of claim 12, further comprising:

adding the integer precision motion vector to a candidate list for a second block.

15. The method of claim 9, further comprising:

adding the fractional precision motion vector candidate to a candidate list for a second block.

16. The method of claim 15, wherein the candidate list for the second block comprises an AMVP candidate list.

17. A device for video decoding, the device comprising:

a memory configured to store video data;

a video decoder comprising one or more processors configured to;

determine a coding mode for a first block is merge mode;

determine a motion vector precision for the first block is integer pixel precision;

construct a merge candidate list for the first block based on video data stored in the memory, wherein the merge candidate list comprises a fractional precision motion vector candidate;

select the fractional precision motion vector candidate to decode the first block;

round the fractional precision motion vector candidate to determine an integer pixel precision motion vector for the first block;

locate a reference block for the first block using the integer pixel precision motion vector.

18. The device of claim 17, wherein the one or more processors are further configured to determine the motion vector precision for the first block is integer pixel precision, the one or more processors are further configured to receive in the encoded video data an indication that the motion vector precision for the first block is integer pixel precision.

19. The device of claim 17, wherein the merge mode comprises a skip mode.

20. The device of claim 17, wherein the one or more processors are further configured to:

determine a coding mode for a second block is other than a merge mode;

determine a motion vector precision for the second block is integer pixel precision;

determine a fractional precision motion vector predictor for the second block;

round the fractional precision motion vector predictor to determine an integer pixel precision motion vector predictor for the second block;

determine a motion vector difference for the second block, wherein the motion vector difference comprises an integer pixel precision difference;

determine an integer pixel precision motion vector for the second block based on the integer pixel precision motion vector predictor and the motion vector difference;

locate a reference block for the second block using the integer pixel precision motion vector.

21. The device of claim 20, wherein to determine the fractional precision motion vector predictor for the second block, the one or more processors are further configured to:

construct an AMVP candidate list for the second block, wherein the AMVP candidate list comprises a second fractional precision motion vector candidate;

select the second fractional precision motion vector candidate as the fractional precision motion vector predictor for the second block.

22. The device of claim 21, wherein the one or more processors are further configured to:

add the integer precision motion vector to a candidate list for a second block.

23. The device of claim 17, wherein the one or more processors are further configured to:

add the fractional precision motion vector candidate to a candidate list for a second block.

24. The device of claim 23, wherein the candidate list for the second block comprises an AMVP candidate list.

25. A computer readable storage medium storing instructions that when executed by one or more processors cause the one or more processors to:

determine a coding mode for a first block is merge mode;

determine a motion vector precision for the first block is integer pixel precision;

construct a merge candidate list for the first block, wherein the merge candidate list comprises a fractional precision motion vector candidate;

select the fractional precision motion vector candidate to decode the first block;

round the fractional precision motion vector candidate to determine an integer pixel precision motion vector for the first block; and

locate a reference block for the first block using the integer pixel precision motion vector.

26-98. -98. (canceled)