JP2003319401A - Moving image coder and decoder thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a coding efficiency of a device for encoding moving image data using a prediction code. <P>SOLUTION: For a vector 55 to be encoded, a distance calculating means 51 finds distance information 54 (or magnitude) of the vector. The distance information 54 is encoded by a distance coding means, and a distance information code 56 is outputted therefrom. The distance information 54 is inputted to a direction information coding means 52 together with the vector 55 to be encoded, direction information is encoded by a method suitable for the distance information 54, and a direction information code 57 is outputted. A multiplexing means 59 outputs the distance information code 56 and the direction information code 57 as a code 58 for the vector. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture coding apparatus and a moving picture loading / decoding apparatus for coding motion vector data of a moving picture.

[0002]

2. Description of the Related Art Since moving image data generally has a large amount of data, high-efficiency coding is performed when it is transmitted from a transmitting device to a receiving device or stored in a storage device. Here, "high-efficiency coding" is a coding process for converting a data string into another data string, and is a process for compressing the data amount.

An interframe predictive coding method is known as a highly efficient coding method for moving image data. Figure 2
Shows a block diagram of this interframe predictive coding.
This encoding method utilizes the fact that moving image data has high correlation in the time direction. That is, since moving image data generally has a high degree of similarity between frame data at a certain timing and frame data at the next timing,
The interframe predictive coding method uses that property.
For example, in a data transmission system using the inter-frame predictive coding method, in the transmitting device, motion vector data representing “motion” from the image of the previous frame to the image of the target frame, and the motion vector from the image of the previous frame. The difference data between the predicted image of the target frame created using the data and the actual image of the target frame is generated, and the motion vector data and the difference data are sent to the receiving device. On the other hand, the receiving device reproduces the image of the target frame from the received motion vector data and difference data.

In the above encoding, when the correlation between the target frame and the preceding frame is high, the information amount of the motion vector data and the difference data becomes small.

The interframe predictive coding method described above is based on the ITU-
T H.261, ITU-T H.263, ISO / IEC MPEG-1, ISO / IEC MPE
It is used in standard systems such as G-2. Further, in these standard methods, a predictive code is used as a method of coding motion vector data. The method of encoding motion vector data by taking ITU-T H.263 as an example will be described below.

In the predictive coding method, as shown in FIG.
The image of each frame consists of multiple blocks (B11, B12, B1
3, B14 ,. ． ． ) And the image data is encoded for each block. That is, for each block, an image similar to the image in the target block is extracted from the image of the previous frame, and the difference between the extracted image and the image in the target block is obtained. As a result, the difference image data from which the redundancy has been removed can be obtained. At this time, the motion vector data of the target block is also obtained.
Then, the difference image data and the motion vector data are encoded for each block to compress the data to be transmitted.

When the motion vector data of a certain block (block to be coded) is coded, first, the motion vector of the block to be coded is predicted based on the motion vector of the block near the block to be coded. A value (hereinafter, a prediction vector) is calculated. Here, as the neighboring blocks used for this prediction, ones that have been previously encoded are selected. Generally, the order of encoding processing is as shown in FIG.
As shown in, starting from the block in the upper left corner, one block is performed for each line. In this case, when a certain block is encoded, the encoding process has already been completed for the block located on the line above the block and the block located on the left side of the block. Therefore, for example, when encoding the motion vector of the block B22, the blocks B11, B12, B1
3, B14 ,. ． ． And the motion vector of block B21 is available.

[0008] According to ITU-T H.263, when predicting a motion vector of a coding target block, a block above the coding target block, an upper right block and a left block are used. That is, for example, block B shown in FIG.
When encoding 22 motion vectors, block B12,
The motion vectors of B13 and B21 are used.

When the prediction vector of the block to be coded is obtained, the difference vector (or prediction error vector) between the actual motion vector of the block to be coded and its prediction vector is then obtained. Then, the X component and the Y component of this difference vector are encoded using variable length codes. The variable length code is, for example, a Huffman code.

A specific example will be described with reference to FIG. In FIG. 4, the actual motion vector of the coding target block is (MVx, MVy), and the motion vectors of the neighboring blocks B1 to B3 used to obtain the prediction vector of the coding target block are (PMV1x, PMV1y), respectively. ,
(PMV2x, PMV2y), (PMV3x, PMV3y). Here, the X component of the prediction vector of the encoding target block is obtained as a median value (that is, an intermediate value) of PMV1x, PMV2x, and PMV3x, and its Y component is obtained as a median value of PMV1y, PMV2y, and PMV3y. To be Then, each difference vector data (X component and Y component of the difference vector) is obtained by the following formula.

X component difference vector data (MVDx) = M
Vx-Median (PMV1x, PMV2x, PMV3x) Y component difference vector data (MVDy) = MVy-Median
(PMV1y, PMV2y, PMV3y) Each difference vector data is encoded using the variable length code shown in FIG. 6 as an example.

A detailed description will be given with reference to FIG. FIG. 5A is an example of a motion vector of a scene in which the image changes little. Here, the actual motion vector of the coding target block is (1, 0), and the motion vectors of the blocks B1 to B3 near the coding target block are (0,
0), (0,0), and (1,0).
In this case, the X component and the Y component of the prediction vector of the encoding target block are obtained by the following equations, respectively.

Prediction vector (x) = Median (0,0,1) = 0 Prediction vector (y) = Median (0,0,0) = 0 Therefore, “prediction vector = (0,0)” is obtained. . The difference vector of the block to be encoded is obtained by the following equation.

Difference vector = actual motion vector of target block? Prediction vector = (1,0)? (0,
0) = (1,0) where “difference vector data (difference vector component)”
= 1 ”, when the code shown in FIG. 6 is used,“ 0010 ”is obtained as encoded motion vector data.
When "difference vector data = 0", "1" is obtained as the encoded motion vector data. Therefore, the coded motion vector data to be transmitted for this block is 5 bits.

As described above, in a scene in which the change in the image is small, the difference vector data becomes small and the information amount of the encoded motion vector data to be transmitted becomes small.

FIG. 5 (b) is an example of a motion vector of a scene in which image changes are almost uniform. Here, the actual motion vector of the encoding target block is (10,? 9),
Also, blocks B1 to B3 in the vicinity of the block to be coded
Motion vectors of (10,? 10), (9,? 9),
(9,? 9). In this case, “difference vector = (1,0)” is obtained. Therefore, even in a scene where the image changes uniformly, the difference vector data becomes small and the information amount of the encoded motion vector data to be transmitted becomes small.

The code shown in FIG. 6 is a code used in ITU-T H.263.

In this code, a data string having a short data length is assigned to difference vector data having a high occurrence frequency, while a data string having a long data length is assigned to difference vector data having a low occurrence frequency. . The occurrence frequency of the difference vector data is statistically obtained in advance. Therefore, the use of such a code increases the probability that motion vector data having a short data length will be transmitted, so that the average amount of information of the motion vector data of each block becomes small.

As described above, in a transmission system using an encoding method such as ITU-T H.263, data relating to a motion vector is compressed using a prediction vector, and the amount of information to be transmitted is reduced. High efficiency.

[0020]

When the one-dimensional difference between the x-component difference vector MVDx and the y-component difference vector MVDy is represented as a two-dimensional difference as in the conventional method, at least one two-dimensional difference vector is obtained. Two bits of information will be assigned. As described above, since it is expected that the frequency of (0, 0) is high as a two-dimensional difference vector generated by predictive coding and variable length coding of a motion vector, a two-dimensional difference vector represented by 2 bits.
It is desired to further compress (0,0) to improve coding efficiency.

In addition, generally, in image coding, the statistical property of a motion vector generated is isotropic (the same in any direction). From this, a vector
The occurrence probability of (x, y) substantially depends on the magnitude of the vector, and the dependence in the x, y direction is low. From this, it is preferable that the code length depends on the size of the vector and does not depend on the direction of the vector.

However, as in the conventional case, when the independent codes are assigned to the x and y components, the above condition is not satisfied. For example, as the variable length code used in H.263, x of the vector (x, y) when the vector (x, y) is encoded using the variable length code shown in FIG. 6, for example.
FIG. 7 shows the sum of both the component and the y component. In this figure, as an example, those in which the sum of vector code lengths is less than 10 are surrounded by thick lines. As shown in this figure, a vector along the x-axis or y-axis direction (the sign of the x-component or y-component vector is near 0)
It is understood that, when the vector is encoded, although the information is encoded with a smaller amount of information, the vector in the diagonal direction requires more information than in the x-axis and y-axis directions.

Therefore, the present invention has the above-mentioned problem, that is, a code for which information of less than 2 bits is assigned to vector (0,0). This is to realize a code that is less dependent on direction. Furthermore, the vector (x,
If we try to assign codes to all combinations of y),
A huge number of codes is required. From this, the present invention provides an encoding device that solves the above two problems with fewer code words.

[0024]

FIG. 8 shows the basic configuration of an encoding apparatus according to the present invention. The present invention provides a coder that decomposes a vector into distance information (size) and direction information, and encodes each to encode the vector. First, with respect to the vector 55 to be encoded, the distance calculation means 51 obtains the distance information 54 (or the size) of the vector. Then, the distance information 54 is encoded by the distance encoding means 53, and the distance information code 56 is output. Further, the distance information 54 is input to the direction information encoding means 52 together with the vector 55 to be encoded, the direction information is encoded by a method according to the distance information 54, and the direction information code 57 is output. Then, in the multiplexing means 59, the distance information code 56 and the direction information code 57 are combined, and the code of the vector
Output as 58. The basic configuration of the decoding device of the present invention is shown in FIG. First, for the code 65 of the vector to be decoded, the distance decoding means 61 outputs distance information 64.
Then, the direction information decoding means decodes the direction information code based on the distance information 64. Then, the direction information 67 of the decoding result is output. Then, the distance information 64 and the direction information 67 are input to the vector reconstructing means 63 to generate a vector to be decoded and output as a vector decoding result 68.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION A motion vector coding apparatus and a motion vector decoding apparatus according to this embodiment are shown in FIG.
It is used in a system for transmitting moving image data as shown in FIG. In this transmission system, each frame of moving image data is divided into a plurality of blocks and encoded / decoded for each block, as shown in FIG.

The interframe predictive coding apparatus 10 comprises a coefficient coding unit 11 and a motion vector coding unit 1.
2 is provided, and the original image data is encoded and output. In addition,
The inter-frame predictive coding device 10 does not necessarily perform the inter-frame predictive coding process on all the frames of the moving image data, but has a function of performing the intra-frame coding process as necessary.

The coefficient coding unit 11 generates coded coefficient data obtained by coding coefficient information generated by coding for each block. The motion vector coding unit 12 also generates coded motion vector data obtained by coding the information about the motion vector for each block.

The inter-frame predictive decoding apparatus 20 comprises a coefficient decoding unit 21 and a motion vector decoding unit 2
2 and reproduces image data based on the coded coefficient data and the coded motion vector data coded by the interframe predictive coding apparatus 10.

The motion vector coding apparatus and the motion vector decoding apparatus of this embodiment correspond to the motion vector coding unit 12 and the motion vector decoding unit 22, respectively, in the system shown in FIG.

FIG. 2 is a block diagram of an interframe predictive coding apparatus. The configuration of this interframe predictive coding device is known and is basically the same as that used in a coding method such as ITU-T H.263.
The motion vector coding apparatus of this embodiment corresponds to the vector entropy coding circuit 41 in FIG. 2, and the function of this circuit is different from the function of the existing vector entropy coding circuit. The configuration and operation of the vector entropy coding circuit 41 will be described later in detail.
The operation of the existing circuit portion will be briefly described below.

When the original image data is input frame by frame, the interframe predictive coding apparatus sequentially executes coding processing on a plurality of blocks obtained by dividing the frame. The orthogonal transformation circuit 31 decomposes the image data into frequency components for each block. The quantization circuit 32 quantizes the output of the orthogonal transformation circuit 31. The output of the quantizer circuit 32 is often referred to as "coefficient data".

An inverse quantization circuit 33, an inverse orthogonal transformation circuit 34,
The decoded image generation circuit 35 is provided to generate the same image as the image that will be reproduced in the decoding device (the interframe predictive decoding device 20 in FIG. 1). The images generated by these circuits are stored in the decoded image storage circuit 36.

The motion vector calculation circuit 37 calculates a motion vector based on the image stored in the decoded image storage circuit 36 and the newly input image. A method for obtaining a motion vector for each block is a known technique. The predicted image generation circuit 38 generates a predicted image based on the image stored in the decoded image storage circuit 36 and the motion vector calculated by the motion vector calculation circuit 37.
That is, the predicted image generation circuit 38 predicts the image of the frame at the next timing from the image of the frame at a certain timing, and outputs the predicted image. This predicted image is an image similarly generated in the decoding device.

The prediction error signal generation circuit 39 generates a signal representing the error between the image actually input and the prediction image generated by the prediction image generation circuit 38. This prediction error signal is the signal transmitted to the decoding device. The prediction error signal is encoded and transmitted. That is, first, the orthogonal transformation circuit 31 and the quantization circuit 32 determine the coefficient data of the prediction error signal. Then, the coefficient entropy coding circuit 40 codes and outputs this coefficient data.

The interframe predictive coding apparatus may use the intraframe code if necessary. In this case, the prediction error signal generation circuit 39 is supplied with “0” instead of the prediction image generated by the prediction image generation circuit 38.

The vector entropy coding circuit 41 is
The motion vector data is encoded for each block. Then, the multiplexing circuit 42 uses the coefficient entropy coding circuit 4
The coded coefficient data coded by 0 and the coded motion vector data coded by the vector entropy coding circuit 41 are multiplexed and output.

As described above, the decoding device generates the same predicted image as the predicted image generated by the interframe predictive coding device. Then, the original image is reproduced using the predicted image and the received prediction error signal and motion vector.

FIG. 10 is a diagram showing an embodiment of an encoding apparatus of the invention. This coding device corresponds to the vector entropy coding circuit 41 in FIG.

The motion vector coding apparatus of this embodiment is
Similar to the existing encoding device, when encoding the motion vector of the encoding target block, (1) create a prediction vector of the encoding target block from the motion vector of the block in the vicinity of the encoding target block, (2) Obtain the difference vector between the actual motion vector of the target block to be encoded and the prediction vector, and (3) generate the encoded motion vector data by encoding each component of the difference vector.

In FIG. 10, when the difference vector 75 is input, the distance calculation unit 71 obtains the distance information 74 corresponding to the distance (size) of the vector. Then, the distance information 74 is encoded by the distance encoding means 73, and the distance information code 76 is output. Furthermore, this distance information 74 is
The vector 75 to be encoded is input to the direction information encoding unit 72, the direction information is encoded by a method according to the distance information 74, and the direction information code 77 is output. The multiplexing unit 79 combines the distance information code 76 and the direction information code 77 into a vector code 78.
Output as.

FIG. 11 is a diagram showing an example of implementation of the distance calculation unit. The distance calculation unit 81 in FIG. 11 corresponds to 71 in FIG. In this example, the difference vector is input,
As the distance, the sum of the absolute values of the x component and the y component of the difference vector is defined as the distance. Then, the distance is output. An example is as follows. In the case of (MVDx, MVDy) = (-1, -1), the distance is | -1 | + | -1 | = 2 and the distance is 2. Regarding the definition of the distance, in addition to this embodiment, a sum of squares, or a weighted one of the x component and the y component such as distance = | MVDx | + 2 · | MVDy | It is possible.

FIG. 12 is a diagram showing an embodiment of the distance encoding unit. This corresponds to 73 in FIG. In this example, the distance encoding unit assigns a variable length code to the input distance S. FIG. 18 shows an example of a variable length code that is assumed to be used in the distance coding unit 93. As an example, when the difference vector is (MVDx, MVDy) = (-1, -1), the distance S is 2, and the variable length code is "0".
01 "is assigned.

FIG. 13 shows an example of the direction information coding unit. This corresponds to 72 in FIG. This direction information coding unit 101
First, in the direction information calculation unit 103, the direction for specifying the vector to be encoded from the plurality of vectors having the same distance from the input distance S and the difference vector (MVDx, MVDy) is determined. Create the indicated direction information (Position). In the present embodiment, the value of this direction information (Position) is given as the Position of the following formula when the distance S and the difference vector (MVDx, MVDy) are given. FIG. 20 shows the direction information (Position) corresponding to the difference vector (MVDx, MVDy) given by the direction information calculation unit 103 of this embodiment. The diamonds in the figure are distances 1, 2, 3,
Vectors showing the same distance are shown for 4, 5, and 6.
As can be seen from the figure, in the vector indicating the same distance, when the distance is S, the direction information (Position) up to 0, 1, 2, ... Then, this direction information (Position) is input to the variable length encoders 102a, 102b, ... Corresponding to each direction information, and the result according to the distance S is selected by the selection unit 104 and output.

FIG. 19 shows an example of a variable length code which is supposed to be used in the direction information coding unit described in FIG. As an example, when the difference vector is (MVDx, MVDy) = (-1, -1), the direction information (Position) is 3 from the above equation, and thus the code "011" is assigned.

FIG. 22 shows an embodiment of the multiplexing unit 159.
In this example, the distance information code "001" and the direction information code "011" are combined to output the code "001011".

Next, FIG. 14 shows an embodiment of the decoding apparatus of the present invention. This decoding device corresponds to the decoding side of the coding device in FIG. Note that in this embodiment of the decoder,
The decoding process of the code “001011” generated in the above embodiment of the encoder will be described as an example.

First, the distance decoding unit 111 outputs distance information 114 for the vector 115 to be decoded.
Then, the direction information decoding unit decodes the direction information code based on the distance information 114. Then, the direction information 117 of the decoding result is output. Then, the distance information 114 and the direction information
117 is input to the vector reconstruction unit 64, a vector to be decoded is generated, and the decoded vector 118 is output.

FIG. 15 is a diagram showing an embodiment of the distance decoding unit 121. This corresponds to the distance decoding unit 111 in FIG. In this example, the distance decoding unit 121 performs variable length decoding on the input variable length code and outputs distance information S.

FIG. 18 shows an example of a variable length code which is supposed to be used in the distance decoding unit described in FIG. When "0010110 ..." is input as the code string, the first 3-bit "001" becomes the code of the distance information S, and the corresponding distance information 2 of the variable length code example of FIG. 18 is the distance decoding unit. It will be output from 121.

FIG. 16 shows the direction information decoding unit of the decoding device.
132 examples are shown. This corresponds to 112 in FIG.
The direction information decoding unit 132 includes a selection unit 134 and variable length decoding units 135a, 135b, 135c, ... According to the distance. The operation will be described using the following example. First, it is assumed that "0010110" is input as the code string as in the example of the distance decoding unit. In this case, the distance decoding unit has already determined that the distance is 2, so 2 is input as the distance. As a result, the selection unit 134 selects the variable length decoding unit 135b corresponding to S = 2.

Next, the variable length decoding unit 165 corresponding to the distance S = 2 will be described with reference to FIG. This corresponds to the variable length coding unit 135b in FIG. As in the above, input "0010110 ...
.. "is assumed. In this case, since the code length of the distance information 2 is known to be 3, 3 bits are deleted from the input code and" 0
Variable length decoding corresponding to S = 2 is performed as "110 ...". In this case, according to FIG. 19, if the distance S = 2, the code having the first 3 bits of "011" has the vector direction information of 3. From this, the tunable decoding unit outputs 3 as direction information.

FIG. 17 is a vector reconstruction unit of the decoding device.
An example of 143 is shown. This corresponds to 113 in FIG.
In this embodiment, the distance information output from the distance decoding unit 121
(S) and the vector direction information (Position) output from the direction information decoding unit 132 are used to describe the equation for reconstructing the difference vector.

As an example, “0010110 ...” is input to the decoding device and the distance from the distance decoding unit is 2, as in the above.
When directional information = 3 is output from the directional information decoding unit, according to the mathematical expression in FIG. 17, it is called a difference vector ⇒ S = distance, Position = vector directional information ⇒ Position is 0, 1, 4, S-1. = 7, different from 4 and S-2 = 6.

⇒Sign = (Position + 2) mod 4 = 1 ⇒Location = (Position + 2) / 4 = 1 ⇒ (MVDx, MVDy) = (location−S, −location) = (−
1, -1) Take. It should be noted that this (-1, -1) is equivalent to the vector (-1, -1) that is the object of encoding in the embodiment on the encoding side, and indicates that it can be correctly decoded.

FIG. 21 is a diagram showing an example of the bit amount necessary for coding a vector when the coding method of the embodiment of the present invention is used. In the range of the thick line in the figure, a vector in which the amount of information is 11 bits or less is shown. Compared with FIG. 7 of the conventional example, a 1-bit code is assigned to the vector (0,0) and the x-axis and y-axis directions are set. It can be seen that the bias of is decreasing.

[0056]

According to the present invention, in vector encoding, a vector is represented by information indicating the magnitude of the vector and a direction indicating the direction, and by assigning a code to each of them, the statistical properties of the actual vector can be obtained. It is possible to generate a suitable and efficient code.

[Brief description of drawings]

FIG. 1 is a diagram showing a moving image data transmission system to which the present invention is applied.

FIG. 2 is a block diagram of an interframe predictive code enable device.

FIG. 3 is a diagram illustrating a process of dividing a frame into blocks.

FIG. 4 is a diagram showing an example of motion vector prediction.

FIG. 5 is a diagram illustrating a processing method for encoding a motion vector.

FIG. 6 is a diagram showing an example of a variable length code.

[Fig. 7] Fig. 7 is a diagram showing an example of the number of bits required for vector coding when the conventional coding method is used.

FIG. 8 is a diagram showing a basic configuration of a codeable device according to the present invention.

FIG. 9 is a diagram showing a basic configuration diagram of a decoding device of the present invention.

FIG. 10 is a diagram showing an embodiment of a codeable device of the present invention.

FIG. 11 is a diagram showing an embodiment of a distance calculation unit of the codeable device according to the present invention.

FIG. 12 is a diagram showing an embodiment of a distance encoding unit of the codeable device according to the present invention.

FIG. 13 is a diagram showing an embodiment of a distance encoding unit of the codeable device according to the present invention.

FIG. 14 is a diagram showing an embodiment of a decoding device of the present invention.

Fig. 15 is a diagram showing an embodiment of a distance decoding unit of the decoding device of the present invention.

FIG. 16 is a diagram showing an embodiment of a direction information decoding unit of the decoding device of the present invention.

FIG. 17 is a diagram showing an embodiment of a vector reconstruction unit of the decoding device of the present invention.

FIG. 18 is a diagram showing an example of a variable-length code assigned to distance information according to the present invention.

FIG. 19 is a diagram showing an example of a variable length code assigned to direction information corresponding to distance information 1 to 5 in the present invention.

FIG. 20 is a diagram showing an example of direction information (Position) of the present invention.

FIG. 21 is a diagram showing the number of bits required for codeability of a vector when the codeability method of the present invention is used.

FIG. 22 is a diagram showing an example of a multiplexing unit.

[Fig. 23] Fig. 23 is a diagram illustrating an example of a variable length decoding unit of direction information of distance = 2.

[Explanation of symbols]

10 interframe predictive coding device 11 Coefficient coding unit 12 Motion vector coding unit 20 interframe predictive decoding device 21 coefficient decoding unit 22 Motion Vector Decoding Unit 31 Orthogonal transformation circuit 32 Quantization circuit 33 Inverse quantization circuit 34 Inverse orthogonal transform circuit 35 Decoded image generation circuit 36 Decoded image storage circuit 37 Motion vector calculation circuit 38 Prediction image generation circuit 39 Prediction error signal generation circuit 40-coefficient entropy coding circuit 41 Vector Entropy Coding Circuit 42 Multiplexing circuit 51 Distance calculation means 52 Direction Information Calculation Means 53 Means for enabling distance code 54 Distance information 55 encoding target vector 56 distance information code 57 Direction information code 58 vector sign 59 Multiplexing means 61 distance decoding means 62 direction information decoding means 63 vector reconstruction means 64 distance information 65 vector sign 67 Direction information 68 Decoding vector 71 Distance calculator 72 Direction information calculation unit 73 Distance code enable part 74 Distance information 75 encoding target vector 76 distance information code 77 Direction information code 78 Vector sign 79 Multiplexer 81 Distance calculator 93 distance coding unit 93 distance coding unit 102a-102n Variable length codeable part 103 Direction Information Calculation Unit 104 Selector 111 distance decoding unit 112 Direction Information Decoding Unit 113 Vector reconstruction section 114 distance information 115 vector sign 117 Direction information 118 decoding vector 121 distance decoding unit 132 Direction Information Decoding Unit 143 Vector reconstruction unit 159 Multiplexing unit 165 Variable Length Decoding Unit with Distance = 2

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Claims (2)

[Claims] 1. A moving picture coding apparatus for dividing each frame of moving picture data and coding a motion vector obtained at the time of coding each block obtained by the division, from a motion vector to be coded Distance calculation means for obtaining distance information of a vector, distance encoding means for assigning a code to the distance information obtained by the distance calculation means, and the same distance determined according to the distance information obtained by the distance calculation means To the direction information coding means and the direction information coding means that specifies the vector direction information representing the direction from the plurality of vectors having And a multiplexing means for multiplexing the code of the vector direction information generated as described above. 2. A moving picture decoding apparatus for decoding a moving picture using a motion vector, comprising: a distance information decoding means for decoding a code representing distance information of a motion vector of a decoding target block, and the distance information decoding means. Direction information decoding means for decoding a code indicating vector direction information indicating a vector direction from a plurality of vectors having the same distance determined according to the distance information decoded by the distance information decoding device. Distance information decrypted by the means,
And a vector reconstructing unit for reconstructing a motion vector to be decoded from the vector direction information decoded by the direction information decoding unit.