KR101318869B1 - Motion Vector Coding Method and Apparatus for Video Coding and Video Coding Method and Apparatus Using Same - Google Patents

Abstract

The present invention relates to a motion vector encoding / decoding method and apparatus for video encoding, and an image encoding / decoding method and apparatus using the same.

The present invention determines a motion vector, predictive motion vectors, and differential motion vectors of a block, determines an average differential motion vector of differential motion vectors, and subtracts a motion determined by subtracting the average differential motion vector from the differential motion vectors. A motion vector encoding method is provided by encoding vectors to generate motion vector encoded data.

According to the present invention, since the value of the component of the differential motion vector can be reduced when predicting and encoding the motion vector, the bit amount of the data encoded by the motion vector can be reduced, thereby improving the encoding efficiency of the video. Can be.

Image, encoding, decoding, motion vector, difference, average, bit amount

Description

Motion vector coding / decoding method and apparatus for video coding, and video coding / decoding method and apparatus using same {Motion Vector Coding Method and Apparatus for Video Coding and Video Coding Method and Apparatus Using Same}

The present invention relates to a motion vector encoding / decoding method and apparatus for video encoding, and an image encoding / decoding method and apparatus using the same. More specifically, the present invention relates to a method and apparatus for improving coding efficiency by reducing the amount of bits generated by encoding a motion vector for motion compensation predictive encoding of a video.

A motion vector encoding and decoding method commonly used in the field of video encoding and decoding is to perform predictive encoding on a motion vector of a motion predicted block using a motion vector of a spatially located neighboring block as a prediction value. That is, since the motion vector of the current block (hereinafter referred to as 'current motion vector') has a close correlation with the motion vector of the neighboring block, the predicted value for the current motion vector from the motion vector of the neighboring block by a predetermined method. After calculating (hereinafter, referred to as 'predictive motion vector'), the encoding efficiency is reduced by significantly reducing the amount of bits to be encoded by encoding only the differential motion vector for the predicted motion vector without encoding the value of the current motion vector itself. In addition, motion estimation is performed using a predetermined search range using the predicted motion vector as an initial search point, thereby determining a motion vector that is more similar to the predicted motion vector in the motion estimation process. That is, by determining a motion vector that is more similar than the predicted motion vector in the motion estimation process, the bit amount of the differential motion vector to be encoded is reduced.

Typically, in the prediction encoding for such a motion vector, the encoding efficiency is increased as the prediction motion vector is similar to the current motion vector for efficient compression. Thus, candidates are generated that generate not only the motion vectors of the spatially adjacent blocks, but also a plurality of predictive motion vectors consisting of the motion vectors of temporally or spatiotemporally adjacent blocks or other motion vectors calculated by combining them. Predictive encoding efficiency can be further increased by predicting and using the most suitable for encoding the current motion vector. In addition, by using a plurality of prediction motion vectors, a plurality of search ranges are defined and motion estimation is performed according to each prediction motion vector, so that the current motion vector can be determined to have a value similar to that of each prediction motion vector. Can be further increased.

Meanwhile, one block, such as a macroblock, may be composed of several subblocks, and each subblock may have a motion vector. Thus, one block may have a plurality of motion vectors. Each motion vector has two components, an x-axis component and a y-axis component. In addition, as the two components constituting the differential motion vector are closer to '0', data generated by encoding the differential motion vector is represented by a smaller number of bits, thereby improving encoding efficiency.

However, according to the conventional motion vector coding scheme, a difference to be coded for one block is required because a block is composed of several subblocks having several motion vectors and the motion vectors of each subblock have two components. Since the number of components of the motion vector is also increased, there is a possibility that the absolute value of the differential motion vector does not approach '0', thereby increasing the number of bits required for encoding the motion vector.

In order to solve the above-described problem, the present invention is mainly used to reduce the amount of bits of data encoded with a motion vector by reducing the value of a component of a differential motion vector when predicting and encoding a motion vector used for motion prediction encoding of a video. There is a purpose.

In order to achieve the above object, the present invention provides a method of encoding a motion vector for a block, comprising: determining motion blocks, predictive motion vectors, and differential motion vectors of a block; Determining an average differential motion vector of the differential motion vectors; And generating motion vector encoded data by encoding the differential differential motion vectors determined by subtracting the average differential motion vector from the differential motion vectors.

According to another object of the present invention, there is provided an apparatus for encoding a motion vector for a block, comprising: a motion vector determiner for determining motion vectors, predicted motion vectors, and differential motion vectors of a block; Determine the differential motion vectors of the differential motion vectors, encode the differential motion vectors and the average differential motion vector determined by subtracting the average differential motion vector from the differential motion vectors, and generate differential differential encoded data; A differential motion vector encoder for calculating a bit amount of data; A differential motion vector encoder encoding differential motion vectors to generate differential coded data, and calculating a bit amount of differential coded data; And a motion vector encoded data generator configured to generate motion vector encoded data including differential encoded data based on at least one of the number of motion vectors in the block, the bit amount of the differentially encoded data, and the bit amount of the differentially encoded data. A motion vector encoding apparatus is provided.

According to still another object of the present invention, there is provided a method of decoding a motion vector of a block, the method comprising: extracting and decoding differential coded data from motion vector coded data to restore average differential motion vectors and differential motion vectors; Reconstructing the differential motion vectors of the block by adding the reconstructed differential motion vectors and the reconstructed average differential motion vector; And reconstructing the motion vectors of the block using the predicted motion vectors of the block and the reconstructed differential motion vectors.

According to still another object of the present invention, in an apparatus for decoding a motion vector of a block, the differential differential coded data extracted from the motion vector coded data is decoded to reconstruct and reconstruct average differential motion vectors and differential motion vectors. A differential motion vector decoder for reconstructing the differential motion vectors of the block by adding the differential motion vectors to be recovered and the average differential motion vectors to be reconstructed; A differential motion vector decoder for decoding differential coded data extracted from the motion vector coded data and reconstructing differential motion vectors of the block; And a motion vector reconstructor for reconstructing the motion vectors of the block by using the predicted motion vectors of the block and the differential motion vectors reconstructed.

According to still another object of the present invention, there is provided a method of encoding an image block by block, the method comprising: determining an average differential motion vector of differential motion vectors determined by using motion vectors and predicted motion vectors of a block; Generating motion vector encoded data for the block by encoding the differential motion vectors determined by subtracting the average differential motion vector from the differential motion vectors; Generating a predictive block by motion compensating the block using the motion vectors; Subtracting the block and the predictive block to generate a residual block; Encoding the residual block to generate encoded residual data; And generating and outputting encoded data including the encoded residual data and the motion vector encoded data.

According to yet another object of the present invention, in the apparatus for encoding an image in units of blocks, an average differential motion vector of differential motion vectors determined using the motion vectors and the predictive motion vectors of the block is determined, and the differential motion is determined. A motion vector encoder for generating motion vector encoded data for the block by encoding the differential difference motion vectors determined by subtracting the average differential motion vector from the vectors; A motion compensator for generating a predictive block by motion compensating the block using the motion vectors; A subtractor which subtracts the block and the predictive block to produce a residual block; An encoder for encoding the residual block to generate encoded residual data; And generating encoded data including the encoded residual data and the motion vector encoded data, and including an encoded data generator.

According to still another object of the present invention, in a method of decoding an image in block units, an average differential motion vector and a differential motion vector are extracted by extracting and decoding differential encoded data from motion vector encoded data included in encoded data. Restoring them; Reconstructing the differential motion vectors of the block by adding the reconstructed differential motion vectors and the reconstructed average differential motion vector; Reconstructing the motion vectors of the block using the predicted motion vectors of the block and the reconstructed differential motion vectors; Generating a prediction block by motion compensating the block using the reconstructed motion vectors; Restoring the residual block by extracting and decoding the encoded residual data from the encoded data; And reconstructing the block by adding the reconstructed residual block and the predictive block.

According to still another object of the present invention, there is provided an apparatus for decoding an image in block units, comprising: an information extractor for extracting motion vector encoded data and encoded residual data from encoded data; Extract and decode the differential coded data from the motion vector coded data to reconstruct the average differential motion vector and the differential motion vectors, and restore the differential motion vectors of the block by adding the reconstructed differential motion vectors and the reconstructed average differential motion vector. A motion vector decoder for reconstructing the motion vectors of the block by using the predicted motion vectors of the block and the reconstructed differential motion vectors; A motion compensator for generating a prediction block by motion compensating the block using the reconstructed motion vectors; A decoder which decodes the encoded residual data and restores the residual block; And an adder for reconstructing the block by adding the reconstructed residual block and the predictive block.

As described above, according to the present invention, since the value of the component of the differential motion vector can be reduced when predicting and encoding the motion vector, the bit amount of the data encoded by the motion vector can be reduced. Encoding efficiency can be improved.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;

A video encoding apparatus (Video Encoding Apparatus), a video decoding apparatus (Video Decoding Apparatus), a motion vector encoding apparatus (Motion Vector Encoding Apparatus) or a motion vector decoding apparatus (Motion Vector Decoding Apparatus) will be described later. Computer), notebook computer, Personal Digital Assistant (PDA), Portable Multimedia Player (PMP), PlayStation Portable (PSP), Mobile Communication Terminal (Mobile Communication Terminal), etc., A communication device such as a communication modem for communicating with various devices or a wired / wireless communication network, a program for encoding or decoding a motion vector, a program for encoding or decoding an image using the motion vector, a memory for storing data, and a program Microprocessor for Operation and Control It means a variety of devices including a.

The video encoded in the bitstream by the video encoding apparatus is real-time or non-real-time through the wired / wireless communication network such as the Internet, a local area wireless communication network, a wireless LAN network, a WiBro network, a mobile communication network, or a cable, a universal serial bus (USB: Universal Serial Bus). The image decoding apparatus may be transmitted to the image decoding apparatus through a communication interface such as), and may be decoded by the image decoding apparatus to restore and reproduce the image.

Although the image encoding apparatus and the image decoding apparatus may be provided with functions for performing intra prediction as well as inter prediction using motion estimation and motion compensation, since there is no direct relationship with the embodiment of the present invention, detailed information is provided to prevent confusion. Omit the description.

In general, a moving picture is composed of a series of pictures, and each picture is divided into blocks. Each block is largely classified into an intra block and an inter block according to an encoding method. The intra-block refers to a block that is coded using Intra Prediction Coding (P-Coding) scheme. The intra-prediction coding is performed by using the pixels of previously decoded and decoded blocks in the current picture, A prediction block is generated by predicting the pixels of the block and a difference value between the pixel of the current block and the pixel of the current block is encoded. Inter-block refers to a block that is coded using Inter Prediction Coding. Inter-prediction coding refers to one or more past pictures or a future picture to generate a prediction block by predicting a current block in the current picture, And the difference value is encoded. Here, a picture referred to to encode or decode the current picture is referred to as a reference picture.

1 is an exemplary diagram for explaining a process of coding a motion vector according to the H.264 / AVC standard.

,

,

및

는 각각 블록 A, 블록 B, 블록 C, 블록 D가 갖는 움직임 벡터이고, 각각은 수평성분 (

,

,

및

)과 수직성분 (

,

,

및

)을 가지는 것으로 정의한다. 그리고 현재 블록의 움직임 벡터(이하 '현재 움직임 벡터'라 칭함)

는 (2,0)이고, 주변 블록의 움직임 벡터인

,

및

는 각각 (2,0), (2,1) 및 (2,2)인 것으로 가정한다. 또한, 전술한 현재 블록의 움직임 벡터에 대한 예측값(이하 '예측 움직임 벡터'라 칭함, PMV: Predicted Motion Vector)

를 수학식 1과 같이 계산하며, 예측 움직임 벡터

는 역시 각각은 수평성분(

)과 수직성분(

)을 가지는 것으로 정의한다.1, a block D is a current block to which a motion vector is to be coded, and a block A, a block B, and a block C represent neighboring blocks for the block D.

,

,

And

Are the motion vectors of the block A, the block B, the block C, and the block D, respectively,

,

,

And

) And the vertical component (

,

,

And

). And a motion vector of the current block (hereinafter referred to as a 'current motion vector').

(2,0), and the motion vector of the neighboring block

,

And

(2,0), (2,1) and (2,2), respectively. In addition, the above-described prediction value for the motion vector of the current block (hereinafter referred to as 'predicted motion vector', PMV: Predicted Motion Vector)

Is calculated as shown in Equation (1), and the predicted motion vector

Is also a horizontal component (

) And the vertical component (

).

의 예측 움직임 벡터

가 구해지면, 수학식 2를 사용하여 부호화해야 할 현재 움직임 벡터에서 예측 움직임 벡터를 차분한 차분 움직임 벡터

를 구할 수 있으며, 이 차분 움직임 벡터는 엔트로피 부호화 등의 미리 정의된 소정의 방법에 의해 부호화되어 저장(또는 전송)된다.Referring to Equation 1, it can be seen that the predicted motion vector for the current motion vector is calculated by Median (□) that calculates the median value of the motion vectors of the neighboring blocks (blocks A, B, C). Using equation (1), the current motion vector

≪ / RTI >

Is obtained, the differential motion vector obtained by subtracting the predictive motion vector from the current motion vector to be encoded using Equation (2).

And the differential motion vector is coded and stored (or transmitted) by a predetermined predetermined method such as entropy coding.

가 (2,0)인 경우, 수학식 1에 의한 중간값을 사용한 예측 움직임 벡터는 (2,1)이 되며, 수학식 2에 의해 차분 움직임 벡터

는 (0, 1)이 된다.As illustrated in FIG. 1, the current motion vector

(2, 0), the predicted motion vector using the intermediate value according to Equation (1) becomes (2,1), and the differential motion vector

(0, 1).

2 is an exemplary diagram illustrating the number of bits per symbol for entropy encoding.

를 도 2에 도시한 바와 같은 가변 길이 부호화 테이블을 이용하여 부호화하면, 모두 4 비트(수평 성분에 대해 1 비트, 수직 성분에 대해 3 비트)가 필요하다. 반면,

인 (2,0)을 예측 움직임 벡터로 사용하면 차분 움직임 벡터

가 (0,0)이 되어, 이를 부호화하는데 소요되는 비트량은 모두 2 비트(수평 성분에 대해 1 비트, 수직 성분에 대해 1 비트)가 된다. 따라서, 중간값을 사용한 예측 움직임 벡터를 사용하는 방법에 비해 2 비트를 감소시킬 수 있다.In predictive coding of motion vectors, differential motion vectors are encoded using a variable length coding table to efficiently compress the motion vectors. For example, the differential motion vector described above with reference to FIG.

Is encoded using the variable length coding table as shown in FIG. 2, all four bits (one bit for the horizontal component and three bits for the vertical component) are required. On the other hand,

(2, 0) is used as the predictive motion vector, the difference motion vector

(0, 0), and the amount of bits required to encode it is 2 bits (1 bit for the horizontal component and 1 bit for the vertical component). Therefore, it is possible to reduce 2 bits as compared with a method using a predictive motion vector using an intermediate value.

On the other hand, when the differential motion vector is encoded using the variable length coding table, as the x-axis component and the y-axis component, which are each component constituting the current motion vector, are closer to '0', the data to be encoded has fewer bits. It is expressed as In addition, one block, such as a macroblock, may be composed of several subblocks and each subblock may have a motion vector, and thus, one block may have a plurality of motion vectors. Therefore, when one block has J (where J is an integer) motion vectors, the components of the motion vector to be encoded are J × 2. For example, in H.264, one 16x16 macroblock may consist of 4x4 subblocks and may have one motion vector for each subblock, so that one macroblock may have 16 motion vectors. In this case, 32 components are required to encode a motion vector for one macroblock.

As described above, since one macroblock is composed of regions having several motions, and thus the number of components of the differential motion vector to be encoded increases, there is a high possibility that the absolute value of the differential motion vector does not approach '0'. There is a problem that the number of bits required for encoding a motion vector increases.

To this end, in an embodiment of the present invention, in the case of a block in which the number of motion vectors to be encoded is larger than the reference number, the difference of the components of all the differential motion vectors in the block is further encoded and the difference is obtained by subtracting the average value from the differential motion vectors. By encoding the partial motion vectors, the compression efficiency is improved by reducing the amount of bits required to encode the motion vector than in the case of encoding the differential motion vectors.

3 is a block diagram schematically illustrating an image encoding apparatus according to an embodiment of the present invention.

Referring to FIG. 3, the image encoding apparatus 300 according to an embodiment of the present invention includes a motion vector encoder 310, a motion compensator 320, a subtracter 330, and residual data. Encoder (Residual Data Encoder, 340), Entropy Encoder (350), Encoding Data Generator (Encoding Data Generator, 360), Residual Data Decoder (370), Adder (Adder, 380), Reference Picture The memory may include a reference picture memory 390 and a controller 392.

The motion vector encoder 310 determines an average differential motion vector of differential motion vectors determined using the motion vectors and the predictive motion vectors of the block, and subtracts the average differential motion vector from the differential motion vectors. By encoding the differential differential motion vectors (Double Differential Motion Vector) determined by the motion vector to generate a motion vector encoding data (Motion Vector Encoding Data) for the block.

To this end, the motion vector encoder 310 receives a block mode for a block from the controller 392 and refers to at least one reference picture stored in the reference picture memory 390 to input the block mode. Block to be currently encoded in units corresponding to (for example, 16 × 16, 16 × 8, 8 × 16, 8 × 8, 8 × 4, 4 × 8, and 4 × 4 pixel units) Motion vector is estimated.

Here, the block mode indicates an encoding mode of the current block and may be, for example, information indicating whether the inter prediction mode is an inter prediction mode and the block size for the inter prediction mode, such as inter 16x16 and inter 8x4. In addition, the block may be a pixel unit having a rectangular or square shape such as 4x4 pixel unit or 4x8 pixel unit as a pixel unit for convenience for encoding an image. However, an image may not always be encoded in a block unit, but may be encoded in a standardized or unstructured area unit. Hereinafter, for convenience of description, an image is encoded in block units.

In this case, the motion vector encoder 310 may receive information indicating a reference picture from the controller 392 and estimate motion vectors of the current block by referring to the reference picture identified by the provided information. In addition, as an alternative thereto, the motion vector encoder 310 may receive only a block mode from the controller 392. When only the block mode is input, the motion vector encoder 310 calculates a difference value for each picture including the current block (hereinafter referred to as a 'current picture') and all available reference pictures located in the temporal vicinity. The motion vectors of the current block may be estimated based on the reference picture having the minimum difference value.

The motion compensator 320 generates a predicted block by motion compensating the current block using the motion vectors of the current block determined by the motion vector encoder 310. To this end, the motion compensator 320 receives the motion vectors of the current block and the index information of the reference picture from the motion vector encoder 310 and predicts by performing motion compensation on the reference picture using the transferred motion vectors. Create a block.

The subtractor 330 subtracts the current block and the prediction block to generate a residual block. That is, the subtractor 330 generates a residual block having a residual signal obtained by subtracting the prediction pixel value of the prediction block from the original pixel value of the current block.

The residual data encoder 340 transforms and quantizes the residual block. That is, the residual data encoder 340 transforms the residual signal of the residual block into a frequency domain, converts each residual signal of the residual block into a transform coefficient, and quantizes the residual block having the transform coefficient to quantize the transform coefficient. Create a residual block with. Here, the residual data encoder 340 uses various transformation techniques for transforming an image signal of a spatial axis into a frequency axis such as a Hadamard transform and a Discrete Cosine Transform Based Transform (DCT based Transform). The residual signal can be converted into the frequency domain, and the residual signal converted into the frequency domain becomes a conversion coefficient. In addition, the residual data encoder 340 converts the transform coefficients of the residual block into dead zone uniform threshold quantization (DZUTQ), a quantization weighted matrix, or an improvement thereof. Quantization can be done using quantization techniques.

In the above description, the residual data encoder 340 transforms and quantizes the residual block, but the residual block may not be transformed or quantized. That is, the residual data encoder 340 may not only perform the quantization process without transforming the residual block into transform coefficients, or may not perform quantization after converting the residual block, and may not even perform both the transformation and quantization processes. . When the transformation and quantization processes are not performed, the residual data encoder 340 may be omitted in the image encoding apparatus 300 according to an embodiment of the present invention.

The entropy encoder 350 entropy encodes a residual block output from the residual data encoder 340, and outputs encoded residual data. That is, the entropy encoder 350 scans the quantized transform coefficients, transform coefficients, or residual signals of the residual block according to various scan methods such as zigzag scan to generate quantized transform coefficient sequences, transform coefficient sequences, or residual signal sequences, and entropy encoding. Encoding is performed using various encoding techniques such as (Entropy Coding). Meanwhile, the functions of the residual data encoder 340 and the entropy encoder 350 may be integrated and implemented as one encoder. That is, when implemented with one encoder, the encoder generates encoded residual data by encoding the residual block.

The encoded data generator 360 generates and outputs encoded data including the encoded residual data and the motion vector encoded data. That is, the encoded data generator 360 generates and outputs encoded data including encoded residual data output from the encoder or entropy encoder 350 and motion vector encoded data output from the motion vector encoder 310. In addition, the encoded data generator 360 may additionally include information about a block mode for the current block that is output from the controller 3920 in the encoded data and output the encoded data. The encoded data generator 360 may be implemented as a multiplexer such as a multiplexer (MUX).

The residual data decoder 370 inverse quantizes and inverse transforms the residual block quantized by the residual data encoder 340. That is, the decoder 370 inversely quantizes the quantized transform coefficients of the angularized residual block to generate a residual block having the transform coefficient, and inversely transforms the inverse quantized residual block to restore the residual block having the residual signal, that is, reconstruction. Generated residual blocks. Here, the residual data decoder 370 may inverse transform and inverse quantize using an inverse transform method and a quantization method used in the residual data encoder 340. In addition, when only the transform is performed in the residual data encoder 340 and no quantization is performed, the residual data decoder 370 performs only inverse transform and does not perform inverse quantization, and performs only quantization in the residual data encoder 340. If no transformation is performed, only inverse quantization may be performed and inverse transformation may not be performed. If the residual data encoder 340 does not perform both the transformation and the quantization, or the residual data encoder 340 is omitted without being configured in the image encoding apparatus 300, the residual data decoder 370 may also perform inverse transformation and inverse. The quantization may not be performed or may be omitted without being configured in the image encoding apparatus 300.

The adder 380 reconstructs the current block by adding the prediction block motion-compensated by the motion compensator 320 and the residual block reconstructed by the residual data decoder 370. The reference picture memory 390 stores the reconstructed current block output from the adder 380 as a reference picture in picture units so that the motion vector encoder 310 or the motion vector compensator 320 of the predictor is the next block or the next block of the current block. It can be used as a reference picture when estimating or compensating for motion to code another block.

The controller 392 applies a predetermined optimal criterion (e.g., rate-distortion optimization criterion) to block modes that can be selected to the current block to be currently encoded in the image. For example, the block mode with the minimum rate-distortion cost) is determined. If the block mode is pre-set in the video encoding apparatus 300, the controller 392 may not be included in the video encoding apparatus 300 and may be selectively omitted. However, the controller 392 is not omitted, and each component in the video encoding apparatus 300 may be omitted. It can play a role in controlling the overall dynamics of the element.

Although not shown in FIG. 3, the image encoding apparatus 300 according to an embodiment of the present invention described above includes an intra prediction unit for intra prediction, an intra prediction unit for intra prediction based on the H.264 / AVC standard, And a deblocking filter unit for deblocking filtering the received signal. In addition, residual data encoder 340 and residual data decoder 370 are based on the H.264 / AVC standard for transform and quantization (or inverse transform and inverse quantization) for a particular picture (e.g., an intra picture). Further calculations may be performed. Here, deblocking filtering refers to a task of reducing block distortion caused by coding an image block by block. The deblocking filter may be applied to a block boundary or a macro block boundary, a deblocking filter may be applied to a macro block boundary, Can be selectively used.

FIG. 4 is a block diagram of a motion vector coding apparatus according to an embodiment of the present invention. Referring to FIG.

The motion vector encoding apparatus according to an embodiment of the present invention may be implemented as a motion vector encoder 310 in the image encoding apparatus 300 according to an embodiment of the present invention described above with reference to FIG. 3. For convenience, it is called a motion vector encoder 310.

The motion vector encoder 310 may include a motion vector determiner 410, a double differential motion vector encoder 420, a differential motion vector encoder 430, and motion vector encoded data. It may be configured to include a generator (Motion Vector Encoding Data Generator, 440).

The motion vector determiner 410 determines motion vectors of the current block, predictive motion vectors of the current block, and differential motion vectors of the current block. That is, the motion vector determiner 410 performs a motion estimation process on the current block to determine motion vectors for each subblock in the current block, predicts each motion vector to determine predicted motion vectors, and motion vectors. The differential motion vectors are determined by subtracting the prediction motion vectors from.

Here, the current block refers to a block to be currently encoded, and the block may be a macroblock or a block in which a plurality of macroblocks are combined. In addition, the motion vectors determined for the current block may include a plurality of motion vectors for a plurality of reference pictures for each subblock of the block. That is, not only one motion vector is determined for each subblock constituting the current block, but a plurality of motion vectors may be determined for each subblock. For example, when the current block is a B type macroblock that is bi-predictively coded, each subblock of the macroblock may have two motion vectors for two reference pictures. Accordingly, a plurality of differential motion vectors and differential motion vectors of a current block to be described later may be determined for each subblock.

The differential motion vector encoder 420 determines an average differential motion vector of the differential motion vectors of the current block and encodes the differential motion vectors and the average differential motion vector determined by subtracting the average differential motion vector from the differential motion vectors. To generate differential coded data, and calculate the bit amount of the differential coded data. Here, each component of the average differential motion vector is determined by dividing each component of the differential motion vectors by twice the number of motion vectors or adding differential motion vectors by each component and dividing by the number of motion vectors for each component. Can be determined.

Referring to FIG. 5, which illustrates differential motion vectors for each subblock of a macroblock, the macroblock includes first to fourth subblocks, and the differential motion vectors of the subblocks are each (x1, y1). Assuming that (x2, y2), (x3, y3) and (x4, y4), the number of motion vectors J in the macroblock is 4, and each component of the mean differential motion vector (xa, ya) is It may be determined as in Equation 3 or Equation 4.

xa = ya = (x1 + x2 + x3 + x4 + y1 + y2 + y3 + y4) / 4 × 2

That is, according to Equation 3, each component of the average differential motion vector may be equally determined by dividing the sum of the components of the differential motion vectors by twice the number of motion vectors.

xa = (x1 + x2 + x3 + x4) / 4, ya = (y1 + y2 + y3 + y4) / 4

That is, according to Equation 4, each component of the average differential motion vector may be determined as a value obtained by adding the differential motion vectors for each component and dividing by the number of motion vectors for each component.

It may be more desirable to use the average differential motion vector determined by equation (3) rather than equation (4). Since each component of the average differential motion vector determined by Equation 3 is the average of both the x-axis component and the y-axis component, the mean differential motion vector determined by Equation 4 is used when calculating the differential motion vector. Because it can be closer to zero than ever. However, Equations 3 and 4 merely illustrate calculation methods for determining the average differential motion vector, and the average differential motion vector is not only calculated based on Equation 3 or Equation 4 but also various other vectors. It can be calculated by the average calculation method.

The differential motion vector encoder 430 generates differential encoded data by encoding differential motion vectors of the current block, and calculates a bit amount of the differential encoded data.

The motion vector encoded data generator 440 may generate motion vector encoded data including differential encoded data based on at least one of a number of motion vectors of the current block, a bit amount of differentially encoded data, and a bit amount of differentially encoded data. Create

To this end, when the number of motion vectors of the current block is larger than the reference number and the bit amount of the differentially encoded data is smaller than the bit amount of the differentially encoded data, the motion vector encoded data generator 440 may transmit the difference to the differential motion vector encoder 420. It is possible to generate motion vector encoded data including differentially encoded data generated by encoding. In this case, when the number of motion vectors is larger than the reference number, the motion vector encoded data generator 440 may generate a difference flag and include the motion vector in the motion vector encoded data.

Further, the motion vector encoded data generator 440 may perform differential encoding when the number of motion vectors of the current block is less than or equal to the reference number, or if the number of motion vectors of the current block is greater than the reference number, If it is greater than or equal to the bit amount of the data, motion vector encoded data including differential encoded data generated by encoding by the differential motion vector encoder 430 may be generated. In this case, when the number of motion vectors is larger than the reference number, the motion vector encoded data generator 440 may generate a difference flag and include the motion vector in the motion vector encoded data.

Here, the difference flag is a flag indicating whether to encode a difference motion vector and may be set as an applied identifier or an unapplied identifier. The application identifier indicates that the motion vector encoded data including the differential encoded data is generated because the bit amount of the differentially encoded data is smaller than the bit amount of the differentially encoded data, and the unapplied identifier indicates that the bit amount of the differentially encoded data is It indicates that motion vector coded data including differential coded data is generated because it is greater than or equal to the bit amount.

Hereinafter, a method of encoding a motion vector using the motion vector encoder 310 will be described.

According to the motion vector encoding method, the motion vector encoder 310 determines motion vectors of the current block, predictive motion vectors of the current block, and differential motion vectors of the current block, and determines an average differential motion vector of the differential motion vectors. The motion vector encoded data is generated by encoding the differential motion vectors and the average differential motion vector determined by subtracting the average differential motion vector from the differential motion vectors.

Here, the motion vector encoder 310 may determine the number of motion vectors of the current block and determine the average differential motion vector only when the number of motion vectors is larger than the reference number. In addition, each component of the average differential motion vector may be determined as a value obtained by dividing the value of each component of the differential motion vectors by twice the number of motion vectors.

The motion vector encoder 310 may further include motion vector coded data including differential coded data when the bit amount of the differential coded data encoded with the differential motion vector is smaller than the bit amount of differential coded data encoded with the differential motion vector. Can be generated. In this case, the motion vector encoded data may further include a difference flag set as an application identifier indicating that the differential motion vector is encoded.

In addition, the motion vector encoder 310 may encode a motion vector including differential encoded data when the bit amount of the differential encoded data encoded with the differential motion vector is greater than or equal to the bit amount of the differential encoded data encoded with the differential motion vector. You can generate data. In this case, the motion vector encoded data may further include a differential flag set as an unapplied identifier indicating that the differential motion vector is encoded.

Here, the current block may be a macroblock or a block in which a plurality of macroblocks are combined, and the motion vectors of the current block may include a plurality of motion vectors for a plurality of reference pictures for each subblock of the block.

Hereinafter, a specific implementation example of a motion vector encoding method according to an embodiment of the present invention will be described with reference to FIG. 6.

6 is a flowchart illustrating a specific implementation of a motion vector encoding method according to an embodiment of the present invention.

The motion vector encoder 310 estimates and determines motion vectors of a block to be encoded, that is, a current block, predicts estimated motion vectors to determine predicted motion vectors, and subtracts predicted motion vectors from the motion vectors to perform differential motion. The vectors are determined (S610).

The motion vector encoder 310 determines whether the number of motion vectors of the current block is greater than the reference number (S620). Here, the reference number is the number of motion vectors of the current block, which is a reference for determining whether to encode differential motion vectors to encode motion vectors of the current block, and is input from a user, transmitted from another device, or otherwise. It can be determined using the information, and can be set to two or more integers.

If the number of motion vectors of the current block is larger than the reference number, the motion vector encoder 310 determines an average differential motion vector of the differential motion vectors of the current block (S630). For example, if the number of motion vectors of the current block is four and the number of references is three, the motion vector encoder 310 determines an average differential motion vector of the differential motion vectors of the current block determined in step S610. Here, the average differential motion vector may be determined using an average calculation method of various vectors such as Equation 3 or Equation 4.

The motion vector encoder 310 determines the bit amount Bdd of the differential coded data and the bit amount Bd of the differential coded data (S640). That is, the motion vector encoder 310 determines the differential motion vectors by subtracting the average differential motion vector determined in step S630 from the differential motion vectors of the current block determined in step S610, and determines the differential motion vectors and the average differential motion vector. Is encoded by various methods such as entropy encoding to generate differential coded data. The number of bits of the differential coded data is determined to determine the bit amount Bdd of the differential coded data. In addition, the motion vector encoder 310 generates differential encoded data by encoding the differential motion vectors of the current block determined in step S610, and determines the number of bits of the differential encoded data to determine the bit amount Bd of the differential encoded data. Decide

The motion vector encoder 310 determines whether the bit amount of the differential coded data is smaller than the bit amount of the differential coded data (S650). When the motion vector encoder 310 determines that the bit amount of the differentially encoded data is smaller than the bit amount of the differentially coded data as a result of the determination in step S650, the motion vector encoder 310 generates a difference flag to encode the differential motion vector (e.g., For example, '1' is set (S660), and motion vector encoded data including differential flag and differential encoded data is generated (S670). In other words, the motion vector encoder 310 may identify the information included in the motion vector encoded data in the motion vector decoding apparatus or the image decoding apparatus as information obtained by encoding the differential motion vector. In step S640, motion vector encoded data including the differential coded data and the differential flag already encoded are generated.

If the motion vector encoder 310 determines that the bit amount of the differential coded data is greater than or equal to the bit amount of the differential coded data as a result of the determination in step S650, the motion vector encoder 310 generates an unapplied identifier indicating that the differential motion vector is encoded (eg, For example, '0' is set (S680), and motion vector coded data including a differential flag and differential coded data is generated (S690). That is, the motion vector encoder 310 may identify a difference flag in which an unapplied identifier is set so that the motion vector decoding apparatus or the image decoding apparatus may identify that the information included in the motion vector encoded data is the information encoding the differential motion vector. In operation S640, motion vector encoded data including the differential encoded data and the differential flag already encoded are generated.

On the other hand, the motion vector encoder 310 generates differential encoded data by encoding differential motion vectors of the current block when the number of motion vectors of the current block is less than or equal to the reference number, as a result of the determination in step S620. Generates motion vector encoded data including a (S692).

In operation S620, the motion vector encoder 310 determines whether the number of motion vectors is greater than the reference number, since the current block is likely to include regions with similar motions when the number of motion vectors of the current block is small. As in the conventional manner, it may be more efficient to encode the differential motion vector. In addition, when the number of motion vectors is larger than the reference number, since the current block is likely to be composed of regions having different motions, it may be more efficient to encode the differential motion vectors as in the exemplary embodiment of the present invention rather than the conventional method. Because it can.

Further, in step S650, the motion vector encoder 310 determines whether the bit amount of the differential coded data is smaller than the bit amount of the differential coded data, or the bit amount of the differential coded data is larger than the bit amount of the differential coded data. In the same case, it is because it is more efficient to encode the differential motion vector as in the conventional method, because the bit amount is increased and the coding efficiency can be further reduced when the differential coded data is transmitted. That is, the motion vector encoder 310 does not unconditionally encode differential motion vectors because the number of motion vectors of the current block is greater than the reference number, so that the current block is likely to be composed of regions having different motions. The conventional differential motion vector encoding method and the differential motion vector encoding method according to an embodiment of the present invention may be selectively applied by comparing the bit amount of the bit rate with the bit amount of the differential encoded data. Although the number of motion vectors of the current block is larger than the reference number, and thus the possibility that the current block is composed of regions having different motions is large, the bit rate of the differentially encoded data is greater than or equal to the bit amount of the differentially encoded data. This is because the encoding of the differential motion vector is not only unnecessary, but also more efficient because the bit amount is saved.

FIG. 7 is a block diagram illustrating a video decoding apparatus according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 7, the image decoding apparatus 700 according to an embodiment of the present invention includes an information extractor 710, an entropy decoder 720, and a residual data decoder. 730), a motion vector decoder 740, a motion compensator 750, an adder 760, and a reference picture memory 770.

The information extractor 710 extracts motion vector encoded data and encoded residual data from the encoded data. To this end, the information extractor 710 receives the encoded data, extracts information about a block mode (eg, an identifier), and outputs information about the extracted block mode. Further, when the block mode is the motion vector skipping mode (for example, when the block mode is the intra 16x16 mode, the intra 4x4 mode, etc.), the information extractor 710 is encoded without extracting the motion vector encoded data from the encoded data. Data can be extracted and output. On the other hand, when the block mode is not the motion vector skipping mode (for example, when the block mode is the inter 16x16 mode, the inter 4x4 mode, the P8x8 mode, and the like), the information extractor 710 encodes the motion vector coded data from the encoded data. Extract residual data and output it. In this case, the information extractor 710 may further extract and output index information about the reference picture from the encoded data.

The entropy decoder 720 decodes the encoded residual data output from the information extractor 710. That is, the entropy decoder 720 decodes binary data of the residual data encoded by using an entropy encoding technique to generate a quantized transform coefficient sequence, and inversely scans by various scan methods such as inverse zigzag scan to perform quantization transform coefficients. Branches produce residual blocks. If the binary data of the encoded residual data is binary data in which transform coefficients are encoded, the residual block decoded by entropy decoder 720 will be a residual block having transform coefficients. If the residual and unquantized residual signal is encoded binary data, the residual block decoded by the entropy decoder 720 may be a residual block having the residual signal.

The residual data decoder 730 inverse quantizes and inversely transforms the residual block decoded by the entropy decoder 720 to restore the residual block. That is, the residual data decoder 730 inverse quantizes the quantized transform coefficients of the decoded residual block output from the entropy decoder 720, and inversely transforms the inverse quantized transform coefficients to restore the residual block having the residual signal. If the residual block decoded by the entropy decoder 720 has the quantized transform coefficients, the residual data decoder 730 performs both inverse quantization and inverse transform, but decodes by the entropy decoder 720. If the residual block has transform coefficients, only inverse transform may be performed without performing inverse quantization. If the residual block decoded by entropy decoder 720 has only residual signals, both inverse quantization and inverse transform may be performed. Otherwise, the residual data decoder 730 is not configured in the image decoding apparatus 700 and may be omitted. In FIG. 7, the entropy decoder 720 and the residual data decoder 730 are illustrated and described as being configured independently. However, the entropy decoder 720 and the residual data decoder 730 may be configured as one decoder (not shown) incorporating each function. Therefore, when configured with one decoder, the decoder decodes the encoded residual data and restores the residual block.

The motion vector decoder 740 extracts and decodes the differential coded data from the motion vector coded data, reconstructs the average differential motion vector and the differential motion vectors, and reconstructs the differential differential motion vectors and the average differential motion vector to be recovered. In addition, the differential motion vectors of the current block are reconstructed, and the motion vectors of the current block are reconstructed using the predicted motion vectors of the current block and the reconstructed differential motion vectors. To this end, the motion vector decoder 740 predicts the motion of the current block in block units corresponding to the block mode according to the information about the block mode output from the information extractor 710 in the reference picture stored in the reference picture memory 770. Determine the vectors, decode the motion vector coded data output from the information extractor 710, reconstruct the differential motion vectors of the current block, and use the reconstructed differential motion vectors and the determined prediction motion vectors to obtain the motion vectors of the current block. Restore

The motion compensator 750 generates a predictive block by motion compensating the current block using the motion vectors of the current block to be reconstructed. That is, the motion compensator 750 generates a prediction block by predicting the reference block indicated by the motion vectors of the current block reconstructed from the reference picture stored in the reference picture memory 770 as the prediction block of the current block. In this case, when the motion compensator 750 uses the reference picture and the index information of the reference picture is output from the information extractor 710, the motion compensator 750 may index the index information of the reference picture among the many reference pictures stored in the reference picture memory 770. The reference picture identified by can be used.

The adder 760 reconstructs the current block by adding the residual block to be recovered and the prediction block. That is, the adder 760 reconstructs the current block by adding the reconstructed residual block output from the decoder or the residual data decoder 730 to the prediction block predicted and output by the motion compensator 750. The reconstructed current block is accumulated in picture units and output as a reconstructed picture or stored in the reference picture memory 770 as a reference picture, and may be used to predict the next block.

Although not shown in FIG. 7, the image decoding apparatus 700 according to an embodiment of the present invention described above deblocking and filtering an intra predictor and a reconstructed current block for intra prediction based on the H.264 / AVC standard. It may further include a deblocking filter and the like. In addition, the residual data decoder 730 may further perform inverse transform and inverse quantization operations on a particular picture (eg, an intra picture) based on the H.264 / AVC standard.

The controller 780 extracts various types of information necessary in the decoding process such as information on the block mode extracted by the information extractor 710 and index information on the reference picture, and then the motion vector decoder 740 and the motion compensator 750. In this case, overall control of all components of the image decoding apparatus 700 is performed.

FIG. 8 is a block diagram schematically showing a motion vector decoding apparatus according to an embodiment of the present invention.

The motion vector decoding apparatus according to an embodiment of the present invention may be implemented as a motion vector decoding unit 740 in the image decoding apparatus 700 according to an embodiment of the present invention described above with reference to FIG. 7. For convenience, the motion vector decoder 740 is called.

The motion vector decoder 740 according to an embodiment of the present invention includes a data extractor 810, a double differential motion vector decoder 820, and a differential motion vector decoder. Decoder 830 and a Motion Vector Reconstructor 840.

When the number of motion vectors of the current block is larger than the reference number, the data extractor 810 extracts differentially encoded data from the motion vector encoded data. That is, the data extractor 810 determines the number of motion vectors of the current block and determines whether the number of motion vectors of the current block is greater than a preset reference number (set equal to the reference number set by the motion vector encoder 310). In this case, the differential differential encoded data is extracted from the motion vector encoded data transmitted from the information extractor 810 and transmitted to the differential differential motion vector decoder 820.

In this case, the data extractor 810 may extract the differential flag before extracting the differential encoded data from the motion vector encoded data, and extract the differential encoded data from the motion vector encoded data according to the set value of the differential flag. Whether or not to extract differentially encoded data may be determined. That is, if the number of motion vectors of the current block is larger than the reference number, the data extractor 810 extracts the difference flag from the motion vector encoded data, and if the set value of the difference flag is an application identifier, the motion vector encoded data Extracts the differentially encoded data from the differential motion vector decoder 820 and transfers the differentially encoded data to the differential motion vector decoder 820. If the set value of the differential flag is an unapplied identifier, the differential motion vector is extracted from the motion vector encoded data and the differential motion vector decoder 830 is applied. To pass).

In addition, the data extractor 810 extracts differential coded data from the motion vector coded data when the number of motion vectors of the current block is less than or equal to the reference number. That is, when the number of motion vectors of the current block is less than or equal to a preset reference number, the data extractor 810 extracts differential coded data from motion vector coded data transmitted from the information extractor 810, and then differential motion vector decoder. Forward to 830.

To this end, the data extractor 810 may determine the number of motion vectors of the current block using information on the block mode transferred from the information extractor 710. For example, if the current block is a 16x16 P macroblock and the block mode is inter 4x4, it may be determined that the current block is divided into four subblocks and has four motion vectors.

The differential motion vector decoder 820 decodes the differential coded data extracted from the motion vector coded data to reconstruct the average differential motion vector and the differential motion vectors, and restore the differential motion vectors and the average differential motion to be reconstructed. The vector is added to reconstruct differential motion vectors of the current block.

The differential motion vector decoder 830 decodes differential coded data extracted from the motion vector coded data, and reconstructs differential motion vectors of the current block. Here, when the differential motion vector decoder 820 and the differential motion vector decoder 830 decode the differential coded data and the differential coded data, respectively, the differential motion vector coder 420 of the motion vector coder 310 is used. The differential motion vector encoder 430 may decode the same or similar method to the encoding method used for encoding. For example, if the differential motion vector encoder 420 and the differential motion vector encoder 430 encode the differential motion vectors and the differential motion vectors using entropy encoding using a variable length encoding table, respectively, the differential motion vector The decoder 820 and the differential motion vector encoder 830 may also decode the differential encoded data and the differential encoded data by using entropy encoding using the same variable length encoding table.

The motion vector reconstructor 840 reconstructs the motion vectors of the block using the predicted motion vectors of the current block and the differential motion vectors reconstructed. That is, the motion vector decompressor 840 predicts the motion vectors of the current block in the same manner as the motion vector encoder 310 determines the predicted motion vectors of the current block, and generates the predicted motion vectors, and the differential motion vectors. The motion vectors of the current block are reconstructed by adding the differential motion vectors of the current block reconstructed by the decoder 820 or the differential motion vector decoder 830 and the generated prediction motion vectors.

According to the motion vector decoding method according to an embodiment of the present invention, the motion vector decoder 740 extracts and decodes the differential coded data from the motion vector coded data to reconstruct the average differential motion vector and the differential motion vectors. Reconstruct the differential motion vectors of the current block by adding the reconstructed differential motion vectors and the reconstructed average differential motion vector, and reconstruct the motion vectors of the current block by using the predicted motion vectors of the current block and the reconstructed differential motion vectors. do.

Hereinafter, a specific implementation example of a motion vector decoding method according to an embodiment of the present invention will be described with reference to FIG. 9.

9 is a flowchart illustrating a specific implementation of a method of decoding a motion vector according to an embodiment of the present invention.

When the motion vector coded data is transmitted from the information extractor 710, the motion vector decoder 740 obtains the number of motion vectors of the current block using the block mode of the current block extracted from the coded data by the information extractor 710. In operation S910, it is determined whether the number of motion vectors of the current block is greater than the preset reference number (S920). Data extracted from the motion vector encoded data varies according to the number of motion vectors of the current block.

If the number of motion vectors of the current block is greater than the reference number, the motion vector decoder 740 extracts a difference flag from the motion vector encoded data, and the difference flag is applied to an application identifier (eg, for example). , '1') is determined (S940). The data extracted from the motion vector encoded data varies depending on the set value of the differential difference flag.

If the difference vector is an application identifier, the motion vector encoder 740 decodes the difference coded data from the motion vector coded data, and restores the average difference motion vector and the difference motion vectors (S950). The differential motion vectors and the average differential motion vector are added to reconstruct the differential motion vectors of the current block (S960).

If the difference vector is a non-applied identifier as a result of the determination in step S940, the motion vector encoder 740 decodes the differential coded data from the motion vector coded data (S670).

On the other hand, if the number of motion vectors of the current block is less than or equal to the reference number in step S920, the motion vector encoder 740 proceeds to step S670 to decode the differentially coded data from the motion vector encoded data to determine the differential motion vector of the current block. Restore them.

When the difference motion vectors of the current block are reconstructed in step S960 or step S970, the motion vector encoder 740 determines the predictive motion vectors of the current block by predicting the motion vectors of the current block, and the reconstructed difference between the determined prediction motion vectors. The motion vectors are added to reconstruct the motion vectors of the current block (S980).

As described above, according to an embodiment of the present invention, instead of encoding differential motion vectors of a block, an average differential motion vector having an average value of differential motion vectors is obtained, and the average differential motion vector is calculated from the differential motion vectors. When the subtraction differential motion vectors are encoded, since each component of the differential motion vectors is close to '0', the bit amount of data generated by using the variable length encoding may be reduced, thereby improving the motion vector encoding efficiency. .

In addition, instead of encoding differential motion vectors for all blocks, only differential motion vectors are encoded when the number of motion vectors of the block is greater than or equal to a certain number, so that each component of differential motion vectors is less likely to be closer to zero. By encoding only the differential motion vectors and encoding the differential motion vectors only when the bit amount of the differentially encoded data is smaller than the bit amount of the differentially encoded data, it is possible to prevent an increase in the amount of bits generated by encoding the motion vector. Therefore, the motion vector coding efficiency can be improved.

In addition, since the bit amount generated by encoding the motion vector can be reduced, the bit amount according to the overall video encoding can be reduced, thereby improving the encoding efficiency.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, although all of the components may be implemented as one independent hardware, some or all of the components may be selectively combined to perform a part or all of the functions in one or a plurality of hardware. As shown in FIG. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art. Such a computer program may be stored in a computer readable storage medium and read and executed by a computer, thereby implementing embodiments of the present invention. As the storage medium of the computer program, a magnetic recording medium, an optical recording medium, a carrier wave medium, or the like may be included.

Furthermore, the terms "comprises", "comprising", or "having" described above mean that a component can be implanted unless otherwise specifically stated, But should be construed as including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Terms used generally, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be interpreted in an ideal or excessively formal sense unless explicitly defined in the present invention.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

As described above, the present invention is applied to an image compression processing field for encoding and decoding a video, and when predicting and encoding a motion vector, the value of a component of the differential motion vector can be reduced, so that the motion vector is encoded. It is a very useful invention that can reduce the amount of bits, thereby generating an effect that can improve the coding efficiency of a video.

1 is an exemplary diagram for explaining a process of encoding a motion vector according to the H.264 / AVC standard.

2 is an exemplary diagram illustrating the number of bits per symbol for entropy encoding;

3 is a block diagram schematically illustrating an image encoding apparatus according to an embodiment of the present invention.

4 is a block diagram schematically illustrating a motion vector encoding apparatus according to an embodiment of the present invention;

5 is an exemplary diagram illustrating differential motion vectors for each subblock of a macroblock;

6 is a flowchart illustrating a specific implementation of a motion vector encoding method according to an embodiment of the present invention;

FIG. 7 is a block diagram schematically showing an image decoding apparatus according to an embodiment of the present invention. FIG.

8 is a block diagram schematically showing a motion vector decoding apparatus according to an embodiment of the present invention.

9 is a flowchart illustrating a specific implementation of a method of decoding a motion vector according to an embodiment of the present invention.

Claims (24)

In the method of encoding a motion vector for a block, Determining motion vectors, predicted motion vectors, and differential motion vectors of the block; Determining an average differential motion vector of the differential motion vectors; And Generating motion vector encoded data by encoding differential differential motion vectors determined by subtracting the average differential motion vector from the differential motion vectors. Wherein the motion vector coding method comprises: The method of claim 1, wherein the determining of the average differential motion vector comprises: And determining the average differential motion vector when the number of motion vectors is larger than a reference number. The method of claim 1, wherein the determining of the average differential motion vector comprises: And a value obtained by dividing a value obtained by adding each component of the differential motion vectors by twice the number of the motion vectors, as each component of the average differential motion vector. The method of claim 1, wherein the generating of the motion vector encoded data comprises: The motion vector including the differential encoded data when the bit amount of the differential encoded data encoded with the differential motion vectors and the average differential motion vector is smaller than the bit amount of the differential encoded data encoded with the differential motion vectors. A motion vector encoding method, characterized by generating encoded data. The method of claim 4, wherein the motion vector encoded data is And a differential flag set to an application identifier indicating that the differential motion vectors and the average differential motion vector are encoded. The method of claim 1, wherein the motion vector encoding method comprises: A motion vector including the differential encoded data when the bit amount of the differential encoded data encoded with the differential motion vectors and the average differential motion vector is greater than or equal to the bit amount of the differential encoded data encoded with the differential motion vector. And further comprising generating coded data. The method of claim 6, wherein the motion vector encoded data, And a differential flag set to an unapplied identifier indicating that the differential motion vectors are encoded. The method of claim 1, wherein the block, A motion vector encoding method, characterized in that a macroblock or a block in which a plurality of macroblocks are combined. The method of claim 1, wherein the motion vectors, And a plurality of motion vectors for a plurality of reference pictures for each subblock of the block. In the apparatus for encoding a motion vector for a block, A motion vector determiner for determining motion vectors, predicted motion vectors, and differential motion vectors of the block; Determine differential differential motion vectors of the differential motion vectors, encode differential motion vectors determined by subtracting the average differential motion vector from the differential motion vectors, and generate the average differential motion vector; A differential motion vector encoder for calculating a bit amount of the differential encoded data; A differential motion vector encoder for generating differential encoded data by encoding the differential motion vectors, and calculating a bit amount of the differential encoded data; And Motion vector encoded data for generating motion vector encoded data including the differential encoded data based on at least one of a number of motion vectors in the block, a bit amount of the differential encoded data, and a bit amount of the differential encoded data. Generator Motion vector encoding apparatus comprising a. The method of claim 10, wherein the motion vector encoded data generator, If the number of the motion vectors is greater than a reference number and the bit amount of the differential coded data is smaller than the bit amount of the differential coded data, motion vector coded data including the differential coded data is generated. Encoding device. The method of claim 11, wherein the motion vector encoded data generator, And if the number of motion vectors is larger than the reference number, generating a difference flag indicating whether to encode a differential motion vector and including the difference vector in the motion vector encoded data. In the method of decoding a motion vector of a block, Extracting and decoding the differential coded data from the motion vector coded data to reconstruct the average differential motion vector and the differential motion vectors; Reconstructing the differential motion vectors of the block by adding the reconstructed differential motion vectors and the reconstructed average differential motion vector; And Reconstructing the motion vectors of the block using the predicted motion vectors of the block and the reconstructed differential motion vectors. And a motion vector decoding step of decoding the motion vector. 14. The method of claim 13, Reconstructing the average differential motion vector and the differential motion vector, And if the number of motion vectors of the block is larger than a reference number, extracting the differential coded data from the motion vector coded data. 14. The method of claim 13, Reconstructing the average differential motion vector and the differential motion vector, And extracting the difference difference flag from the motion vector encoded data and extracting the difference difference encoded data from the motion vector encoded data when the difference difference flag is set to an application identifier. The method of claim 15, wherein the motion vector decoding method comprises: Extracting the differential flag from the motion vector encoded data, and if the differential flag is set to an unapplied identifier, extracting and decoding differential encoded data from the motion vector encoded data to restore differential motion vectors; Motion vector decoding method characterized in that. The method of claim 13, wherein the motion vector decoding method comprises: And if the number of motion vectors of the block is less than or equal to a reference number, extracting and decoding differential coded data from the motion vector coded data, and reconstructing differential motion vectors. . An apparatus for decoding a motion vector of a block, Decoding the differential coded data extracted from the motion vector coded data to reconstruct the average differential motion vector and the differential motion vectors, and add the reconstructed differential motion vectors and the reconstructed average differential motion vector to perform the differential motion of the block. A differential motion vector decoder to reconstruct the vectors; A differential motion vector decoder for decoding differential coded data extracted from motion vector coded data and reconstructing differential motion vectors of the block; And A motion vector reconstructor for reconstructing the motion vectors of the block by using the predicted motion vectors of the block and the reconstructed differential motion vectors. Motion vector decoding apparatus comprising a. The apparatus of claim 18, wherein the motion vector decoding apparatus comprises: And a data extractor, wherein the data extractor extracts the differential coded data from the motion vector coded data when the number of motion vectors of the block is larger than a reference number. The apparatus of claim 18, wherein the motion vector decoding apparatus comprises: And a data extractor, wherein the data extractor extracts the differential coded data from the motion vector coded data when the number of motion vectors of the block is less than or equal to a reference number. In the method of encoding the video in block units, Determining an average differential motion vector of the differential motion vectors determined using the motion vectors and the predictive motion vectors of the block; Generating motion vector encoded data for the block by encoding the differential motion vectors determined by subtracting the average differential motion vector from the differential motion vectors; Generating a predictive block by motion compensating the block using the motion vectors; Subtracting the block and the prediction block to generate a residual block; Encoding the residual block to generate encoded residual data; And Generating and outputting encoded data including the encoded residual data and the motion vector encoded data. Image encoding method comprising a. In the device for encoding the video in block units, Determine an average differential motion vector of differential motion vectors determined using the motion vectors of the block and the predictive motion vectors, and encode the differential motion vectors determined by subtracting the average differential motion vector from the differential motion vectors; A motion vector encoder for generating motion vector encoded data for the block; A motion compensator for generating a predictive block by motion compensating the block using the motion vectors; A subtractor for generating a residual block by subtracting the block and the prediction block; An encoder for encoding the residual block to generate encoded residual data; And Generating encoded data including the encoded residual data and the motion vector encoded data, and encoding data generator. An image encoding apparatus comprising a. In the method of decoding a video in block units, Extracting and decoding the differential coded data from the motion vector coded data included in the coded data and reconstructing the average differential motion vector and the differential motion vectors; Reconstructing the differential motion vectors of the block by adding the reconstructed differential motion vectors and the reconstructed average differential motion vector; Reconstructing the motion vectors of the block using the predicted motion vectors of the block and the reconstructed differential motion vectors; Generating a prediction block by motion compensating the block using the reconstructed motion vectors; Restoring a residual block by extracting and decoding encoded residual data from the encoded data; And Reconstructing the block by adding the reconstructed residual block and the prediction block Image decoding method comprising a. An apparatus for decoding a video in block units, An information extractor for extracting motion vector encoded data and encoded residual data from the encoded data; Extract and decode the differential coded data from the motion vector coded data to reconstruct the average differential motion vector and the differential motion vectors, and add the reconstructed differential motion vectors and the reconstructed average differential motion vector to perform a differential motion of the block. A motion vector decoder for reconstructing vectors and reconstructing motion vectors of the block using the predicted motion vectors of the block and the reconstructed differential motion vectors; A motion compensator for generating a prediction block by motion compensating the block using the reconstructed motion vectors; A decoder configured to decode the encoded residual data to recover a residual block; And An adder for reconstructing the block by adding the reconstructed residual block and the prediction block; Video decoding apparatus comprising a.

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