阅读说明：本技术 用于对运动矢量进行编码/解码的方法和装置 (Method and apparatus for encoding/decoding motion vector ) 是由 李振荣 郑丞洙 闵正惠 李善一 于 2015-11-02 设计创作，主要内容包括：公开了运动矢量解码方法及运动矢量编码方法,所述运动矢量解码方法包括：通过使用空间上与当前块相关的空间候选块的运动矢量来获取预测运动矢量；获取当前块的运动矢量与预测运动矢量之间的残差运动矢量,以及表示多个运动矢量分辨率中当前块的运动矢量分辨率的信息；基于当前块的运动矢量分辨率与最小运动矢量分辨率之间的差值来放大残差运动矢量；以及基于预测运动矢量和放大后的残差运动矢量来重构当前块的运动矢量；其中,所述多个运动矢量分辨率包括大于一像素单元的分辨率的像素单元的分辨率。(Disclosed are a motion vector decoding method and a motion vector encoding method, the motion vector decoding method including: obtaining a prediction motion vector by using a motion vector of a spatial candidate block spatially related to the current block; obtaining a residual motion vector between a motion vector of a current block and a predicted motion vector, and information representing a motion vector resolution of the current block among a plurality of motion vector resolutions; amplifying a residual motion vector based on a difference between a motion vector resolution of the current block and a minimum motion vector resolution; and reconstructing a motion vector of the current block based on the prediction motion vector and the enlarged residual motion vector; wherein the plurality of motion vector resolutions includes a resolution of a pixel unit that is greater than a resolution of a pixel unit.)

1. A motion vector decoding method, comprising:

obtaining a prediction motion vector by using a motion vector of a spatial candidate block spatially related to the current block;

obtaining a residual motion vector between the motion vector of the current block and the predicted motion vector, and information indicating a resolution of the motion vector of the current block among a plurality of resolutions of the motion vector;

amplifying the residual motion vector based on a difference between a motion vector resolution of the current block and a minimum motion vector resolution; and

reconstructing a motion vector of the current block based on the prediction motion vector and the enlarged residual motion vector;

wherein the plurality of motion vector resolutions includes a resolution of a pixel unit that is greater than a resolution of a pixel unit.

2. A motion vector encoding method comprising:

determining a motion vector for a current block, and a motion vector resolution for the current block from among a plurality of motion vector resolutions;

obtaining a prediction motion vector by using a motion vector of a spatial candidate block spatially related to the current block;

obtaining a residual motion vector between the motion vector of the current block and the predicted motion vector of the current block;

downscaling the residual motion vector based on a difference between a motion vector resolution of the current block and a minimum motion vector resolution; and

encoding the reduced residual motion vector and information representing a motion vector resolution of the current block,

wherein the plurality of motion vector resolutions includes a resolution of a pixel unit that is greater than a resolution of a pixel unit.

3. A non-transitory computer-readable medium for recording a bitstream, the bitstream comprising:

an encoded residual motion vector between a motion vector of a current block and a prediction motion vector of the current block; and

information representing a motion vector resolution of the current block among a plurality of motion vector resolutions,

wherein the prediction motion vector is obtained by using a motion vector of a spatial candidate block spatially related to the current block,

wherein the residual motion vector is downscaled based on a difference between a motion vector resolution and a minimum motion vector resolution of the current block to encode the residual motion vector, and

wherein the plurality of motion vector resolutions includes a resolution of a pixel unit that is greater than a resolution of a pixel unit.

Technical Field

The present disclosure relates to video encoding and decoding methods, and more particularly, to methods and apparatuses for encoding and decoding a motion vector of a video image by predicting the motion vector.

Background

In codecs such as h.264 Advanced Video Coding (AVC) and High Efficiency Video Coding (HEVC), a motion vector of a block previously encoded and adjacent to a current block or a motion vector of a co-located block in a previously encoded picture may be used for a prediction motion vector of the current block, thereby predicting a motion vector of the current block.

In the video encoding and decoding method, in order to encode an image, one picture may be divided into macroblocks, and each macroblock may be prediction-encoded by using inter prediction or intra prediction.

Inter prediction is a method of compressing an image by removing temporal redundancy between pictures, and motion estimation encoding is a representative example of inter prediction. In motion estimation coding, each block in a current picture is predicted by using at least one reference picture. A reference block most similar to the current block is searched for within a predetermined search range by using a predetermined evaluation function.

A current block is predicted based on a reference block, and a residual block obtained by subtracting a prediction block generated by the prediction from the current block is encoded. Here, in order to accurately perform prediction, a search range of a reference picture is interpolated to generate a sub-pixel unit pixel smaller than an integer pixel unit pixel, and the generated sub-pixel unit pixel is inter-predicted.

Disclosure of Invention

Technical effects

According to the motion vector decoding and encoding apparatus and method of the present disclosure, the optimal prediction motion vector and resolution of the motion vector can be determined, thereby efficiently encoding or decoding video, and the complexity of the apparatus can be reduced.

It will be appreciated by those of ordinary skill in the art that the objects and advantages that may be achieved by the present disclosure are not limited to what has been particularly described hereinabove, and other objects of the present disclosure will become more clearly understood from the following detailed description.

Drawings

Fig. 1a is a block diagram of an apparatus for encoding a motion vector according to an embodiment.

Fig. 1b is a flow chart of a method of encoding a motion vector according to an embodiment.

Fig. 2a is a block diagram of an apparatus for decoding a motion vector according to an embodiment.

Fig. 2b is a flow chart of a method of decoding a motion vector according to an embodiment.

Fig. 3a is a diagram illustrating interpolation for performing motion compensation based on various resolutions.

Fig. 3b is a diagram of motion vector resolution for 1/4 pixel cells, 1/2 pixel cells, one pixel cells, and two pixel cells.

Fig. 4a is a diagram of a candidate block for obtaining a current block of a candidate predicted motion vector.

Fig. 4b shows a process of generating candidate predicted motion vectors according to an embodiment.

Fig. 5a is a diagram of a coding unit and a prediction unit according to an embodiment.

Fig. 5b shows a part of a prediction unit syntax for transmitting a motion vector resolution that has been adaptively determined according to an embodiment.

Fig. 5c shows a part of a prediction unit architecture for transmitting a motion vector resolution that has been adaptively determined according to another embodiment.

Fig. 5d shows a part of a prediction unit architecture for transmitting a motion vector resolution that has been adaptively determined according to another embodiment.

Fig. 6a is a diagram for explaining generation of a candidate merge list by using a plurality of resolutions according to an embodiment.

Fig. 6b is a diagram for explaining generation of a candidate merge list by using a plurality of resolutions according to another embodiment.

Fig. 7a shows a pixel pointed to by two motion vectors with different resolutions.

Fig. 7b shows the pixels and different resolution motion vectors that make up the picture quadrupled in extension.

Fig. 8 is a block diagram of a video encoding apparatus based on encoding units according to a tree structure according to an embodiment of the present disclosure.

Fig. 9 illustrates a block diagram of a video decoding apparatus based on tree-structured encoding units according to an embodiment.

Fig. 10 shows a concept of a coding unit according to an embodiment.

Fig. 11 shows a block diagram of a coding unit based video encoder according to an embodiment.

Fig. 12 shows a block diagram of a coding unit based video decoder according to an embodiment.

Fig. 13 illustrates deeper coding units and partitions according to depth according to an embodiment.

Fig. 14 illustrates a relationship between a coding unit and a transform unit according to an embodiment.

Fig. 15 illustrates a plurality of items of encoded information according to an embodiment.

Fig. 16 illustrates a deeper coding unit according to depth according to an embodiment.

Fig. 17, 18, and 19 illustrate the relationship between a coding unit, a prediction unit, and a transform unit according to an embodiment.

Fig. 20 illustrates a relationship between a coding unit, a prediction unit, and a transform unit according to the coding mode information of table 1.

Fig. 21 shows a physical structure of a disk storing a program according to an embodiment.

Fig. 22 shows a disc drive that records and reads a program by using a disc.

Fig. 23 shows the overall configuration of a content providing system for providing a content distribution service.

Fig. 24 illustrates an external structure of a mobile phone to which the video encoding method and the video decoding method of the present disclosure are applied according to an embodiment.

Fig. 25 shows an internal structure of the mobile phone.

Fig. 26 shows a digital broadcasting system employing a communication system according to an embodiment.

Fig. 27 illustrates a network structure of a cloud computing system using a video encoding apparatus and a video decoding apparatus according to an embodiment.

Best Mode for Carrying Out The Invention

According to an aspect of the present disclosure, a motion vector encoding apparatus includes: a predictor configured to acquire candidate prediction motion vectors of a plurality of predetermined motion vector resolutions by using spatial candidate blocks and temporal candidate blocks of a current block, and determine a prediction motion vector of the current block, a motion vector of the current block, and a motion vector resolution of the current block by using the candidate prediction motion vectors; and an encoder configured to encode the following information: the motion vector prediction apparatus includes information indicating a predicted motion vector of a current block, a residual motion vector between the motion vector of the current block and the predicted motion vector of the current block, and information indicating a resolution of the motion vector of the current block, wherein a plurality of predetermined motion vector resolutions include a resolution of a pixel unit greater than a resolution of a pixel unit.

The predictor may search for a reference block of pixel units of a first motion vector resolution by using a set of first candidate motion vectors including one or more candidate predicted motion vectors selected from the candidate predicted motion vectors; and searching for a reference block of a pixel unit of a second motion vector resolution by using a set of second candidate motion vectors including one or more candidate predicted motion vectors selected from the candidate predicted motion vectors, wherein: the first motion vector resolution and the second motion vector resolution are different from each other; and the set of first candidate predictive motion vectors and the set of second candidate predictive motion vectors may be acquired from candidate blocks different from each other among candidate blocks included in the spatial candidate block and the temporal candidate block.

The predictor may search for a reference block of pixel units of a first motion vector resolution by using a set of first candidate motion vectors including one or more candidate predicted motion vectors selected from the candidate predicted motion vectors; and may search for a reference block of pixel units of a second motion vector resolution by using a set of second candidate motion vectors including one or more candidate predicted motion vectors selected from the candidate predicted motion vectors, wherein: the first motion vector resolution and the second motion vector resolution may be different from each other, and the set of first candidate predicted motion vectors and the set of second candidate predicted motion vectors may include a different number of candidate predicted motion vectors from each other.

When the pixel unit of the resolution of the motion vector of the current block is greater than the pixel unit of the minimum motion vector resolution, the encoder may downscale (down-scale) the residual motion vector according to the resolution of the motion vector of the current block, thereby encoding the residual motion vector.

When a current block is a current coding unit constituting an image, the same motion vector resolution is determined for each coding unit, and a prediction unit predicted in an AMVP (advanced motion vector prediction) mode exists in the current coding unit, an encoder may encode information representing the motion vector resolution of the prediction unit predicted in the AMVP mode as information representing the motion vector resolution of the current block.

When a current block is a current coding unit constituting an image, the same motion vector resolution is determined for each prediction unit, and a prediction unit predicted in an AMVP (advanced motion vector prediction) mode exists in the current coding unit, an encoder may encode information indicating the motion vector resolution of each prediction unit predicted in the AMVP mode in the current block as information indicating the motion vector resolution of the current block.

According to an aspect of the present disclosure, a motion vector encoding apparatus includes: a predictor configured to acquire candidate prediction motion vectors of a plurality of predetermined motion vector resolutions by using spatial candidate blocks and temporal candidate blocks of a current block, and determine a prediction motion vector of the current block, a motion vector of the current block, and a motion vector resolution of the current block by using the candidate prediction motion vectors; and an encoder configured to encode the following information: information indicating a predicted motion vector of the current block, a residual motion vector between the motion vector of the current block and the predicted motion vector of the current block, and information indicating a resolution of the motion vector of the current block, wherein the predictor: searching for a reference block of a pixel unit of a first motion vector resolution by using a first set of candidate motion vectors including one or more candidate predicted motion vectors selected from the candidate predicted motion vectors; and searching for a reference block of a pixel unit of a second motion vector resolution by using a set of second candidate motion vectors including one or more candidate predicted motion vectors selected from the candidate predicted motion vectors, wherein: the first motion vector resolution and the second motion vector resolution are different from each other; and the set of first candidate predictive motion vectors and the set of second candidate predictive motion vectors are acquired from candidate blocks different from each other among candidate blocks included in the spatial candidate block and the temporal candidate block, or include candidate predictive motion vectors different in number from each other.

According to an aspect of the present disclosure, a motion vector encoding apparatus is configured to: generating a Candidate Merge List (Merge Candidate List) including at least one Candidate Merge of the current block, and determining and encoding a motion vector of the current block by using a motion vector of one Candidate Merge of the at least one Candidate Merge included in the Candidate Merge List, wherein the Candidate Merge List includes a motion vector obtained by downscaling the motion vector of the at least one Candidate Merge included in the Candidate Merge List according to a plurality of predetermined motion vector resolutions.

The narrowing may include: selecting one of peripheral pixels around a pixel pointed to by the motion vector of the minimum motion vector resolution based on the resolution of the motion vector of the current block instead of selecting the pixel pointed to by the motion vector of the minimum motion vector resolution; and adjusting the motion vector of the minimum motion vector resolution to point to the selected pixel.

According to an aspect of the present disclosure, a motion vector decoding apparatus includes: an acquirer configured to acquire candidate prediction motion vectors of a plurality of predetermined motion vector resolutions by using a spatial candidate block and a temporal candidate block of a current block, acquire information representing the prediction motion vector of the current block from the candidate prediction motion vectors, and acquire a residual motion vector between the motion vector of the current block and the prediction motion vector of the current block and information representing the motion vector resolution of the current block; and a decoder configured to reconstruct the motion vector of the current block based on the residual motion vector, information representing a predicted motion vector of the current block, and motion vector resolution information of the current block, wherein the plurality of predetermined motion vector resolutions include a resolution of a pixel unit greater than a resolution of a pixel unit.

The candidate predicted motion vectors of the plurality of predetermined motion vector resolutions may include: a first set of candidate predicted motion vectors comprising one or more candidate predicted motion vectors at a first motion vector resolution; and a second set of candidate predicted motion vectors comprising one or more candidate predicted motion vectors at a second motion vector resolution, wherein: the first motion vector resolution and the second motion vector resolution may be different from each other; and the set of first candidate predictive motion vectors and the set of second candidate predictive motion vectors may be acquired from candidate blocks different from each other among candidate blocks included in the spatial candidate block and the temporal candidate block, or may include a number of candidate predictive motion vectors different from each other.

When a pixel unit of a resolution of a motion vector of the current block is greater than a pixel unit of a minimum motion vector resolution, the decoder may enlarge (up-scale) the residual motion vector according to the minimum motion vector resolution, thereby reconstructing the residual motion vector.

When a current block is a current coding unit constituting an image, the same motion vector resolution is determined for each coding unit, and a prediction unit predicted in an AMVP (advanced motion vector prediction) mode exists in the current coding unit, an acquirer acquires information representing the motion vector resolution of the prediction unit predicted in the AMVP mode from a bitstream as information representing the motion vector resolution of the current block.

According to an aspect of the present disclosure, a motion vector decoding apparatus is configured to: generating a Candidate Merge List (Merge Candidate List) including at least one Candidate Merge of the current block, and determining and decoding a motion vector of the current block by using a motion vector of one Candidate Merge of the at least one Candidate Merge included in the Candidate Merge List, wherein the Candidate Merge List includes a motion vector obtained by downscaling the motion vector of the at least one Candidate Merge included in the Candidate Merge List according to a plurality of predetermined motion vector resolutions.

According to an aspect of the present disclosure, a motion vector decoding apparatus includes: an acquirer configured to acquire candidate prediction motion vectors of a plurality of predetermined motion vector resolutions by using a spatial candidate block and a temporal candidate block of a current block, acquire information representing the prediction motion vector of the current block from the candidate prediction motion vectors, and acquire a residual motion vector between the motion vector of the current block and the prediction motion vector of the current block and information representing the motion vector resolution of the current block; and a decoder configured to reconstruct the motion vector of the current block based on the residual motion vector, information representing a predicted motion vector of the current block, and motion vector resolution information of the current block, wherein the candidate predicted motion vectors of the plurality of predetermined motion vector resolutions include: a first set of candidate predicted motion vectors comprising one or more candidate predicted motion vectors at a first motion vector resolution; and a second set of candidate predicted motion vectors comprising one or more candidate predicted motion vectors at a second motion vector resolution, wherein: the first motion vector resolution and the second motion vector resolution are different from each other; and the set of first candidate predictive motion vectors and the set of second candidate predictive motion vectors are acquired from candidate blocks different from each other among candidate blocks included in the spatial candidate block and the temporal candidate block, or include candidate predictive motion vectors different in number from each other.

According to an aspect of the present disclosure, there may be provided a non-transitory computer-readable recording medium in which a program for executing a motion vector decoding method is recorded.