Motion picture decoding device and method thereof

Video decoding apparatus and method {MOTION PICTURE DECODING DEVICE AND METHOD THEREOF}

<p>The present invention relates to a video encoding apparatus and a video decoding apparatus having an inter-field prediction mode. </p>

<p>Since moving picture data generally has a large amount of data, high-efficiency encoding is performed when it is transmitted from a transmitting device to a receiving device or stored in a storage device. Here, "high-efficiency encoding" is encoding processing for converting an arbitrary data string into another data string, and refers to processing for compressing the data amount.</p><p>The moving picture data mainly consists of only frames, and some consist of fields. Hereinafter, a conventional technique of mainly compressing a field image will be described.</p><p>As a highly efficient encoding method for moving picture data, an inter-frame/field prediction encoding method is known. </p><p>Fig. 1 shows a block diagram of this inter-frame/field predictive coding. </p><p>In this encoding method, video data having high correlation in the time direction is used. Briefly explaining the operation of Fig. 1, a subtractor 39 generates a difference image between an input original image and a predicted image, and the orthogonal transform means 31, quantization means 32, and coefficient entropy encoding the difference image. Encoding is performed by means (40). In addition, the difference image is restored from the output of the quantization unit 32 by the inverse quantization unit 33 and the inverse orthogonal transformation unit 34, and the difference image restored by the decoded image generating unit 35 and the prediction used at the time of encoding. A coded picture is restored from the picture. The reconstructed image is stored in the decoded image storage means 36, and the motion vector calculation means 37 calculates a motion vector with respect to the next input image, and based on the motion vector, the predicted image generation means 38 ) to generate a predicted image. The generated motion vector is encoded by the vector entropy encoding means 41 and is output through the MUX 42 together with the coefficient encoded data encoded by the coefficient entropy encoding means 40 . That is, since moving picture data generally has a high degree of similarity between frame/field data at an arbitrary timing and frame/field data at the next timing, the inter-frame/field predictive encoding method uses its properties. For example, in a data transmission system using an inter-frame/field prediction coding method, motion vector data indicating "motion" from the image of the previous frame/field to the image of the target frame/field in the transmitting apparatus, and the preceding frame / Generates difference data between the predicted image of the target frame/field and the actual image of the target frame/field created using the motion vector data from the image of the field, and sends these motion vector data and difference data to the receiving device . On the other hand, the receiving device reproduces the image of the target frame/field from the received motion vector data and difference data. </p><p>Although this frame/inter-field predictive encoding in Fig. 1 has outlined the outline of frame/inter-field predictive encoding, frame predictive encoding and field predictive encoding will be described below. </p><p>2 and 3 show the above-described ISO/IEC MPEG-2/MPEG-4 (hereinafter, MPEG-2, MPEG-4), and as of August 2002, ITU-T and ISO/IEC being jointly standardized. -T H. 264/ISO/IEC MPEG-4 Part 10 (Advanced Video Coding: AVC) Final Committee Draft ("Joint Final Committee Draft (JFCD) of Joint Video Specification (ITU-T REC, H. 264/USO/ IEC 14496-10 AVC)", JVT-D157, or ISO/IEC JTC1/S02/WG11 MPEG02/N492, July 2002, Klagenfurt, AT) (hereinafter abbreviated as AVC FCD) commonly used field images. This is a description of the format at the time of encoding. </p><p>That is, each frame is composed of two fields, that is, a top field and a bottom field. FIG. 2 is a diagram for explaining positions of pixels of luminance and chrominance and fields to which they belong. As shown in Fig. 2, a luminance first line 50a, a luminance third line 50b, a luminance fifth line 50c, a luminance seventh line 50d ... Odd-numbered lines such as etc. belong to the top field, and the luminance second line 51a, the luminance fourth line 51b, the luminance sixth line 51c, the luminance eighth line 51d ... The even-numbered lines, etc., belong to the bottom field. Similarly for the color difference components, the first color difference line 52a, the color difference third line 52b ... Odd-numbered lines such as etc. belong to the top field, and the color difference second line 53a, the color difference fourth line 53b ... The even-numbered lines, etc., belong to the bottom field.</p><p>The top field and the bottom field represent images from different viewpoints. Next, the spatiotemporal arrangement of the top field and the bottom field will be described with reference to FIG. 3 .</p><p>3 and later, since the technology of the present invention relates to the vertical component of a motion vector, in this specification, pixels with a horizontal component are not shown, and all horizontal components of a motion vector are assumed to be 0 for convenience. In addition, the positional relationship of the pixels of the luminance and color difference of each field is correctly shown.</p><p>In FIG. 3 , the vertical axis represents the pixel position of the vertical component of each field, and the horizontal axis represents the passage of time. In addition, since there is no displacement of the position by the field in the horizontal component of the pixel of each image, illustration and description of the pixel in the horizontal direction are omitted in Fig. 3 .</p><p>As shown in Fig. 3, the pixel position of the chrominance component has a vertical component shifted by 1/4 pixel from the pixel position in the luminance field. In addition, this is for satisfying the pixel position relationship as shown in Fig. 2 when a frame is constituted by both fields of the top and bottom. Between both adjacent fields of each top and bottom (64a:65a, 65a:64b ...) is about 1/60 of a second in the case of NTSC format as a base. The time from the top field to the top field (64a: 64b ...) or from the bottom field to the bottom field (65a: 65b ...) is an interval of about 1/30 second.</p><p>Hereinafter, the frame prediction coding mode and field prediction of a field image employed in MPEG-2 or AVC FCD will be described. </p><p>FIG. 4 illustrates a method of constructing a frame from two consecutive fields (adjacent top and bottom fields) in the frame prediction mode. </p><p>4 , the frame is reconstructed into two temporally continuous fields (top and bottom fields). </p><p>5 illustrates a frame prediction mode. In Fig. 5, it is assumed that each frame 84a, 84b, 84c, ... is already reconstructed as two consecutive fields (top and bottom fields) as described in Fig. 4 . In this frame prediction mode, encoding is performed on an encoding target frame composed of both top and bottom fields. Also, as a reference picture, a single reference frame is constructed from two fields (top and bottom fields) accumulated for continuous reference, and is used for prediction of the previous encoding target frame. Then, the two frame images are coded according to the block diagram shown in FIG. In the case of this frame prediction coding mode, as to the motion vector expression method, a zero vector, that is, (0, 0), points to a spatially co-located pixel. Specifically, for the luminance pixel 82 belonging to the frame #2 (84b), the motion vector representing the motion vector (0, O) represents the pixel position 81 of the frame #1 (84a).</p><p>Next, the field prediction encoding mode will be described. </p><p>6 is a diagram for explaining a prediction method in an inter-field prediction mode. In the field prediction mode, the encoding target is a single top field (94a, 94b, ...) or bottom field (95a, 95b, ...) input as an original image. In addition, as a reference picture, a top field or a bottom field accumulated in the past can be used. Here, that the original picture field and the reference field have the same parity is generally defined as that both the original picture field and the reference field are top fields or both are bottom fields. For example, in the field prediction of the same parity of reference numeral 90 in FIG. 6, both fields of the original picture field 94b and the reference field 94a are top fields. Similarly, the difference in parity between the original picture field and the reference field is generally defined as one of the original picture field and the reference field, one of which is a top field and the other of which is a bottom field. For example, in the field prediction of different parity indicated by reference numeral 91 in FIG. 6 , the original picture is the bottom field 95a, and the reference is the top field 94a. Then, the original image field and the reference field are encoded according to the block diagram shown in FIG.</p><p>Further, in the prior art, motion vectors are calculated based on the positions of pixels in each frame/field in both the frame mode and the field mode. A method of calculating a motion vector in a conventional method and a method of mapping pixels when a motion vector is given will be described.</p><p>Fig. 7 is a diagram defining the coordinates of a frame/field image, widely used in encoding of MPEG-2, MPEG-1, AVC FCD, and the like. In Fig. 7, a white circle is a defining position 181 of a pixel in a target frame/field. Here, with respect to the coordinates in this frame/field image, the origin (0, 0) is at the upper left of the screen, and the defining positions of pixels are 1, 2, 3, ... in order in the horizontal and vertical directions. value is assigned. That is, the coordinates of the nth pixel in the horizontal direction and the mth pixel in the vertical direction are (n, m). In accordance with this, the coordinates of the pixel-to-pixel interpolated position are also defined. That is, as for the position 180 of the black circle in FIG. 7, since it is located 1.5 pixels in the horizontal direction and 2 pixels in the vertical direction from the upper left pixel, the coordinates of the position 180 are (1.5, 2.0) is expressed as Further, in the field image, only half the pixels of the frame image are in the vertical direction, but also in this case, the position of the pixel existing in each field is treated as a reference as in FIG. 7 . </p><p>The definition of a motion vector between fields will be described using the coordinate system of FIG. 7 . </p><p>8 is a view for explaining a conventional method of calculating a motion vector between corresponding pixels between fields. In order to define a motion vector, the position of the reference source and the position of the reference destination are required. Then, a motion vector is defined between these two points. Here, a motion vector between a point whose coordinates 201 in the reference field is (Xs, Ys) and a point whose coordinates 202 is (Xd, Yd) in the reference field is calculated. In the conventional method of calculating the motion vector between pixels corresponding to the fields, the motion vector is obtained in the same manner as described below, regardless of the reference source and the reference destination of the top field or the bottom field. That is, the reference source field coordinates 201 (Xs, Ys) and the reference field coordinates 202 (Xd, Yd) are input to the motion vector calculating means 200, and the motion vector 203 between these two points is As , (Xd-Xs, Yd-Ys) is given.</p><p>9 is a diagram for explaining a method of calculating a pixel indicated by a motion vector defined between fields in the prior art. Here, it is assumed that the motion vector is derived by the method of FIG. 8 described above. In order to obtain the coordinates of the reference destination, the position of the reference source and the motion vector are required. In the case of Fig. 9, (X, Y) of the motion vector 211 is given to a point where the coordinates 212 in the reference field are (Xs, Ys), and a reference destination field obtained using both of them is given. It is assumed that the coordinates within the In the conventional method of calculating the motion vector between pixels corresponding to the fields, the position of the reference field is obtained by the same method described below, regardless of whether the reference source and reference destination are the top field or the bottom field. That is, the motion vector 211 (X, Y) and the reference source field coordinates 212 (Xs, Ys) are input to the pixel correspondence means 210, and as the reference destination field coordinates 213, the coordinates (Xs+) X, Ys+Y) is given.</p><p>The definition of the relationship between the vector and the pixel position in Fig. 9 described above is the same for the luminance component and the chrominance component. Here, in MPEG-1/MPEG-2/AVC FCD, which is a general moving picture coding method, only the luminance component is coded as a vector, and the vector of the chrominance component is derived by scaling the luminance component. In particular, in AVC FCD, since the number of vertical and horizontal pixels is half of the number of pixels of the luminance component, the motion vector for obtaining the predicted pixel of the chrominance component is scaled by exactly 1/2 of the motion vector of the luminance component. It is determined that one</p><p>FIG. 10 is a diagram for explaining a method of obtaining a chrominance component motion vector from such a conventional luminance component motion vector. </p><p>That is, when the luminance motion vector 221 is (MV_x, MV_y) and the chrominance motion vector 222 is (MVC_x, MVC_y), the chrominance component motion vector 222 is generated by the chrominance component motion vector generating unit ( 220) by, </p><p><maths num="1"><df>(MVC_x, MVC_y) = (MV_x/2, MV_y/2)</df></maths></p><p>It is obtained according to the formula In this derivation method, in the conventional method, it is irrespective of whether prediction is performed between fields of the same parity or between fields of different parity.</p><p>Further, in the AVC FCD, as the precision of the motion vector of the luminance component, 1/4 pixel precision can be taken. From this, as the result of Equation (1), as the precision of the motion vector of the chrominance component, a vector having a precision of 1/8 pixel precision to the decimal point or less can be taken.</p><p>A method of calculating an interpolation pixel of a color difference component, defined in AVC FCD, will be described with reference to FIG. 11 . </p><p>In Fig. 11, black circles indicate integer pixels, and dotted white circles indicate interpolation pixels. Here, the interpolation pixel G(256) is the horizontal coordinate of the point A(250) and the point C(252) internally divided by α:1-α, and the coordinate in the vertical direction is the point A(250) and the vertical coordinates of the point B(251) are internalized by β:1-β. Here, α and β are values greater than or equal to 0 and less than 1. When the interpolation pixel G(256) defined at the position as described above is calculated, the surrounding integer pixels A(250), B(251), C(252), D(253) and α and β are used. , is approximately obtained as follows.</p><p><maths num="2"><df>G=(1-α)·(1-β)·A + (1-α)·β·B + α·(1-β)·C + α·β·D</df></maths></p><p>The interpolation method of the pixel of the color difference component using FIG. 11 is an example for obtaining the interpolated pixel, and there is no problem even if another calculation method is used. </p>

<solutionproblem><p>In the case of this field coding mode, in the prediction between fields having different original picture fields and different reference fields, that is, different parity, zero vectors of both motion vectors of the luminance component and the chrominance component are not parallel in the definition of AVC FCD. That is, according to the conventional definition, when a prediction is performed using a motion vector of a chrominance component obtained from a motion vector of a luminance component, a pixel at a position spatially displaced from the luminance component is used. This will be explained using FIG. 12 . In FIG. 12 , it is assumed that the top field 130 , the bottom field 131 , and the top field 132 are temporally continuous with time. Here, the bottom field 131 is to be encoded using the top field 130 . In this case, in the inter-field encoding, a motion vector between the same line of each field is defined as zero in the vertical direction. For this reason, when the zero vector (0, 0) is assigned to the pixel 133a on the second line of luminance belonging to the bottom field 131, this pixel is the pixel ( 135a). Similarly, when a zero vector (0, 0) is assigned to the pixel 134a of the first line of color difference belonging to the bottom field 131 , this pixel is the pixel 137a of the first line of the color difference of the top field 130 . ) is predicted from Similarly, the 3rd line pixel 133b of luminance and the 2nd line pixel 134b of chrominance belonging to the top field 132 have the 3rd line pixel 135b of luminance and chrominance on the bottom field 131, respectively. It is predicted from the second line pixel 137b of Also, since it is preferable that the motion vectors are parallel to the color difference and the luminance, if the luminance motion vector is set to the current state, the pixels with the original color difference 134a and 134b are predicted from the positions of the respective 136a and 136b. will have to</p><p>As described above, in prediction between fields with different parity, </p><p>The zero vectors of luminance and chrominance are not parallel. </p><p>that was explained. This causes the following problem in AVC FCD, even for all vectors, in prediction between fields with different parity. 13 and 14 illustrate this problem. According to the AVC FCD, it presents a problem. In addition, since the subject of the present invention relates only to the vertical component of the motion vector, in the following description, all horizontal components of the motion vector are set to 0 for convenience.</p><p>Fig. 13 is a diagram for explaining a problem in obtaining a chrominance component motion vector from a luminance component motion vector in the prior art when the reference destination is the bottom field and the reference source is the top field. </p><p>In AVC FCD, as shown in Equation 1, since the number of pixels in the vertical and horizontal pixels is half of the number of pixels in the luminance component, the motion vector for obtaining the predicted pixel of the chrominance component is 1/ It is determined to be scaled by 2. This is regardless of whether the motion vector is predicted between frames, between fields of the same parity, or between fields of different parity.</p><p>Now, this definition indicates that there is a problem in obtaining a motion vector of chrominance from a motion vector of luminance defined between fields of different parity. In Fig. 13, the pixel 140 on the first line of the reference source top field luminance component has (0, 1) as a prediction vector, and as a result, the pixel position 141 on the second line of the reference bottom field luminance component is used as the predicted value. indicates.</p><p>In this case, a motion vector of a color difference pixel belonging to the same block is obtained as a motion vector (0, 1/2) according to Equation (1). And, when prediction is made using a motion vector (0, 1/2) as the predicted value of the first line pixel 142 of the reference source top field color difference component, it is 1/ from the first line pixel of the reference source bottom field color difference component. The pixel position 143 shifted downward by two pixels is used as the predicted value.</p><p>In this case, the luminance motion vector (0, 1) and the chrominance motion vector (0, 1/2) are not parallel. Preferably, it is necessary to use the predicted pixel position 145 of the chrominance component of the reference bottom field to which a chrominance motion vector parallel to the luminance motion vector is applied.</p><p>Fig. 14 is a diagram for explaining a problem in obtaining a chrominance component motion vector from a luminance component motion vector in the prior art when the reference destination is the top field and the reference source is the bottom field. As in the description of FIG. 13 , in FIG. 14 , the pixel 150 on the first line of the reference source bottom field luminance component has (0, 1) as a prediction vector, and as a result, the pixel on the second line of the reference source top field luminance component The position 151 is indicated as a predicted value.</p><p>In this case, a motion vector of a color difference pixel belonging to the same block is obtained as a motion vector (0, 1/2) according to Equation (1). And, when prediction is made using a motion vector (0, 1/2) as the predicted value of the first line pixel 152 of the reference source bottom field color difference component, it is 1/ from the first line pixel of the reference top field color difference component. The pixel position 153 shifted downward by two pixels is used as the predicted value.</p><p>In this case, the luminance motion vector (0, 1) and the chrominance motion vector (0, 1/2) are not parallel. Preferably, it is necessary to use the predicted pixel position 155 of the chrominance component of the reference top field to which the motion vector of the chrominance parallel to the motion vector of the luminance is applied.</p><p>As described above, when the parity between the reference destination and the reference source field is different, the conventional prediction method refers to a pixel at a position shifted in luminance and chrominance. This results in a predicted image that is out of color difference. </p><p>Also, in the above description, when the motion vector of the luminance and the motion vector of the chrominance are included in the time direction, that is, the time axis direction from the reference source field to the reference field, it means whether they are parallel or non-parallel. is being used as The same applies to the description below.</p><p>It is an object of the present invention to provide a moving picture encoding device and a moving picture decoding device capable of improving the coding efficiency, particularly by improving the prediction efficiency of color difference components in coding between different field pictures. </p></solutionproblem><meansproblemsolution><p>The present invention solves the above problems. </p><p>The video encoding apparatus of the present invention is a video encoding apparatus that performs inter-field motion compensation prediction on a video signal composed of a plurality of fields, and generates a motion vector of a chrominance component from a motion vector of a luminance component. a selection means comprising: motion vector generating means; and selecting one of the chrominance component motion vector generating means to be used for generation of the chrominance component motion vector by inputting parity between a reference destination field and a reference source field of the motion vector as input; The color difference component motion vector generating means selected by ? generates a predictive vector of the color difference component from the motion vector information of the luminance information. </p><p>A moving picture decoding device of the present invention is a moving picture decoding device that performs inter-field motion compensation prediction on a moving picture signal composed of a plurality of fields, and generates motion vectors of chrominance components from motion vectors of luminance components. and selecting means for selecting one of the chrominance component motion vector generation means to be used for generation of the chrominance component motion vector by inputting parity between a reference destination field and a reference source field of the motion vector as input; It is characterized in that the color difference component motion vector generating means selected by the chrominance component generates a predictive vector of the color difference component from the motion vector information of the luminance information. </p><p>According to the present invention, since a chrominance component motion vector generated by a method suitable for each is used according to the parity of the reference destination field and the reference source field, the difference in arrangement of the luminance pixel and the chrominance pixel or the allocation to the top and bottom fields It is possible to solve the problem of the color difference component motion vector caused by the method or the like. </p></meansproblemsolution><effectiveness><p>According to the present invention, even between fields with different parity, the motion vector of the chrominance component parallel to the motion vector of the luminance component can be obtained. can be solved </p></effectiveness>

<p>&lt;Example&gt;</p><p>First, an embodiment of the present invention in encoding will be described. </p><p>In the embodiment of the present invention, as a moving picture encoding apparatus for performing inter-field motion compensation prediction on a moving picture signal composed of a plurality of fields, a plurality of chrominance component motions that generate a chrominance component motion vector from a luminance component motion vector and selecting means for selecting a chrominance component motion vector generation means to be used for generation of a chrominance component motion vector based on parity between a reference destination field and a reference source field of the motion vector, comprising vector generation means, the selection means selected by the selection means It is characterized in that the color difference component motion vector generating means generates a predictive vector of the color difference component from the motion vector information of the luminance information. Here, the selection means selects to generate a motion vector of a chrominance component parallel to the luminance component.</p><p>If the chrominance component motion vector from the reference source field to the reference field is parallel to the luminance component motion vector from the reference source field to the reference field, the luminance component motion vector and the chrominance component motion vector from the reference source field to the reference field Since the spatial displacements of are equal, that is, the spatial positional relationship between the luminance component motion vector and the chrominance component motion vector is maintained, color shift between fields is eliminated. </p><p>Importantly, in the prior art, even if the luminance component motion vector and the chrominance component motion vector as mathematical expressions are parallel, when mapped to the relationship between the luminance pixels constituting each field and the chrominance pixels, they are not parallel. that is. </p><p>Here, as the plurality of color difference component motion vector generating means described above, the following three types are provided. First, the first color difference component motion vector generating means is selected by the selection means when the reference destination field and the reference source field have the same parity. The second chrominance component motion vector generating means is selected by the selection means when the reference destination field is the top field and the reference source field is the bottom field. The third color difference component motion vector generating means is selected by the selection means when the reference destination field is the bottom field and the reference source field is the top field.</p><p>The method of obtaining the motion vector of the chrominance component parallel to the motion vector of the luminance component depends on the parity of the reference source field and the reference field of the motion vector. When both fields have the same parity, the former is the top field and the latter is In the case of the bottom field and the case where the former is the bottom field and the latter is the top field, the calculation methods are different from each other. From this, in the embodiment of the present invention, an appropriate one is selected from among the means for generating a vector of a chrominance component parallel to a motion vector of a luminance component of three types by a reference source and a reference field, and the motion vector of the chrominance component is determined create</p><p>Specifically, when the reference destination field and the reference source field have the same parity, in the first color difference component motion vector generating means, the value of the vector component is 1 in the vertical direction for one pixel of the luminance component of the field image. When the motion vector of the luminance component representing motion is MVy, and the value of the vector component is 1 as a unit, MVCy is the motion vector of the chrominance component representing the vertical motion of one pixel of the chrominance component of the field image,</p><p> MVCy=MVy÷2</p><p>save with </p><p>Then, when the reference destination field is the top field and the reference source field is the bottom field, in the second color difference component motion vector generating means, the value of the vector component is 1 in the vertical direction for one pixel of the luminance component of the field image. When the motion vector of the luminance component representing the motion of ,</p><p> MVCy=MVy÷2+0.25</p><p>save with </p><p>Further, when the reference destination field is the bottom field and the reference source field is the top field, in the third color difference component motion vector generating means, the value of the vector component is 1 in the vertical direction for one pixel of the luminance component of the field image. When the motion vector of the luminance component representing the motion of ,</p><p>MVCy=MVy÷2-0.25</p><p>is saved with </p><p>Also, depending on the definition, there are cases where the units representing the motion of one pixel of the luminance component motion vector and the chrominance component motion vector are different. Here, it is assumed that when the definition of the luminance component motion vector changes by 4, motion in the luminance image for one pixel is indicated, and when the definition of the chrominance component motion vector changes by 8, the motion within the chrominance image for one pixel is represented. In this case, when the reference destination field and the reference source field have the same parity, in the first color difference component motion vector generating means, when the motion vector of the luminance component is MVy and the motion vector of the color difference component is MVCy,</p><p>MVCy=MVy</p><p>save with </p><p>In the case of the same vector definition, when the reference destination field is the top field and the reference source field is the bottom field, the second chrominance component motion vector generating means sets the luminance component motion vector as MVy and the chrominance component motion vector as MVy. When using MVCy,</p><p> MVCy=MVy+2</p><p>save with </p><p>In the case of the same vector definition, when the reference destination field is the bottom field and the reference source field is the top field, the third chrominance component motion vector generating means sets the luminance component motion vector as MVy and the chrominance component motion vector as MVy. When using MVCy,</p><p> MVCy=MVy-2</p><p>save with </p><p>In addition, since the encoding method of the embodiment of the present invention can be used also as a decoding method, the decoding apparatus basically has the same function as the encoding apparatus and operates similarly. </p><p>In the following embodiments, the encoding apparatus will be mainly described. Further, since the present invention relates to a vertical component of a motion vector, all horizontal components of a motion vector are set to 0 for convenience. Also, the embodiment relating to the decoding device has the same configuration as the embodiment of the encoding device.</p><p>Hereinafter, an embodiment will be described assuming that the present invention is applied to an AVC FCD. </p><p>15 is a diagram for explaining a method of calculating a chrominance component motion vector from a luminance component motion vector in the embodiment of the present invention. In the embodiment of the generation means for generating the motion vector of the color difference component from the motion vector of the luminance component in the field prediction in the present embodiment, the generation means includes three types of color difference component motion vector generation means and one selection means is composed of</p><p>The operation of the embodiment of the present invention in Fig. 15 will be described below. </p><p>First, a motion vector 231 of a given luminance component is defined as (MV_x, MV_y). Then, the luminance component vector is supplied as input to the first chrominance component motion vector generating unit 233 , the second chrominance component motion vector generating unit 234 , and the third chrominance component motion vector generating unit 235 . Then, each output is input to the selection means 230 . Then, in the selection means 230, the first, second, and third chrominance component motion vectors are based on the inputted information on the parity 237 of the reference source field of the motion vector and the parity 238 of the reference destination of the motion vector. One of the outputs of the generating means is selected and output as the vector components (MVC_x, MVC_y) of the motion vector 232 of the chrominance component.</p><p>16 is a diagram for explaining a first chrominance component motion vector generating means. </p><p>In the present embodiment, a luminance motion vector 261 having a vector value of (MV_x, MV_y) is input to the first chrominance component motion vector generating means 260, and the luminance motion vector 261 having a vector value of (MVC1_x, MVC1_y) is input. It shows that a motion vector candidate 262 of one color difference is output. The first chrominance motion vector candidate 262 is obtained by the chrominance component motion vector generating means 260 from the luminance motion vector 261 by the following equation,</p><p><maths num="3"><df>(MVC1_x, MVC1_y) = (MV_x/2, MV_y/2)</df></maths></p><p>is calculated according to Then, the obtained motion vector candidate 262 of the first color difference is output to the selection unit.</p><p>Fig. 17 is a diagram for explaining a second chrominance component motion vector generating means. </p><p>In the present embodiment, a luminance motion vector 271 having a vector value of (MV_x, MV_y) is input to the second chrominance component motion vector generating means 270, and the luminance motion vector 271 having a vector value of (MVC2_x, MVC2_y) is input. It shows that the motion vector candidate 272 of two color differences is output. Then, the motion vector candidate 272 of the second chrominance is obtained by the chrominance component motion vector generating means 270 from the motion vector 271 of the luminance by the following equation,</p><p><maths num="4"><df>(MVC2_x, MVC2_y) = (MV_x/2, MV_y/2 + 1/4)</df></maths></p><p>is calculated according to Then, the obtained motion vector candidate 272 of the second color difference is output to the selection unit.</p><p>Fig. 18 is a diagram for explaining a third chrominance component motion vector generating means. </p><p>In the present embodiment, a luminance motion vector 281 having a vector value of (MV_x, MV_y) is input to the third chrominance component motion vector generating unit 280, and a vector value of (MVC3)x, MVC3_y) is input. It shows that the motion vector candidate 282 of the third color difference having a color difference is output. The third chrominance motion vector candidate 282 is obtained by the chrominance component motion vector generating means 280 from the luminance motion vector 281 by the following equation,</p><p><maths num="5"><df>(MVC3_x, MVC3_y) = (MV_x/2, MV_y/2 - 1/4)</df></maths></p><p>is calculated according to Then, the obtained motion vector candidate 282 of the third color difference is output to the selection unit.</p><p>19 is a view for explaining an embodiment of the selection means 240 in the present invention. </p><p>First, in the present embodiment, the parity 247 of the reference source field of the motion vector and the parity 248 of the reference field of the motion vector are determined by the condition determination table 241, respectively, and the color difference component motion vector generating means to select. selection information 249 of is output. In the present embodiment, using this condition determination table 241, when both the reference destination field and the reference source field are the same, selection information for selecting the first color difference component motion vector candidate 244 is output. In addition, when the reference destination field is the top field and the reference source field is the bottom field, selection information for selecting the second chrominance component motion vector candidate 245 is output. Then, when the reference destination field is the bottom field and the reference source field is the top field, selection information for selecting the third chrominance component motion vector candidate 246 is output.</p><p>Here, the first chrominance component motion vector candidate 244 corresponds to the symbol 262 of FIG. 16, the second chrominance component motion vector candidate 245 corresponds to the symbol 272 of FIG. 17, and the third chrominance component motion vector candidate ( 246 is respectively connected to reference numeral 282 in Fig. 18 . In addition, the selector 243 selects one of the first chrominance component motion vector candidate 244 , the second chrominance component motion vector candidate 245 , and the third chrominance component motion vector candidate 246 according to the above-described selection information 249 . One is selected and (MVC_x, MVC_y) is output as the motion vector 242 of the chrominance component.</p><p>20 is a diagram illustrating an example of calculating a vector of a chrominance component from a vector of a luminance component when a reference destination is a bottom field and a reference source is a top field according to an embodiment of the present invention. </p><p>In the example of Fig. 20, the luminance motion vectors (MV_x, MV_y) for predicting the pixel 160 of the reference source top field luminance component are (0, 1). In this case, the pixel position 161 of the reference bottom field luminance component is selected for prediction of the luminance pixel 160 . With respect to such a vector, a process of obtaining a chrominance component motion vector for use in prediction of the reference source top-field chrominance component pixel 162 according to the configuration of Fig. 15 of the present embodiment will be described below.</p><p>First, in the case of FIG. 20, the reference destination field is the bottom field, and the reference source field is the top field. From this, the third chrominance component motion vector candidate is selected as the selection information 249 by the condition determination table 241 of FIG. Here, according to Equation 5, the third chrominance component motion vector candidate is,</p><p><maths num="6"><df>(MVC3_x, MVC3_y) = (MV_x/2, MV_y/2 - 1/4) = (0/2, 1/2 - 1/4) = (0, 1/4)</df></maths></p><p>becomes this Then, this value is output as a motion vector 242 of the color difference component in FIG. When this vector (0, 1/4) is applied to the pixel 162 of the reference source top field color difference component, the pixel position 163 of the reference bottom field color difference component is used as a predicted value. In Fig. 20, the positional relationship in the vertical direction of each pixel follows the actual case. As can be seen from FIG. 20 , it can be seen that the luminance component motion vectors (0, 1) and the chrominance component motion vectors (0, 1/4) are parallel. Accordingly, the color difference between the luminance component and the color difference component, which has been a problem in the prior art, is solved by the present invention.</p><p>Similarly, FIG. 21 is a diagram showing an example of calculating a vector of a chrominance component from a vector of a luminance component when the reference destination is the top field and the reference source is the bottom field according to the embodiment of the present invention. </p><p>In the example of Fig. 21, the luminance motion vectors MV_x and MV_y for predicting the pixel 170 of the reference source bottom field luminance component are (0, 1). In this case, the pixel position 171 of the reference-top-field luminance component is selected for prediction of the pixel 170 of the reference-source bottom-field luminance component. With respect to such a vector, a process for obtaining a chrominance component motion vector for use in prediction of the reference source bottom field chrominance component pixel 172 according to the configuration of FIG. 14 of the present embodiment will be described below.</p><p>First, in the case of FIG. 21, the reference destination field is the top field and the reference source field is the bottom field. From this, the second chrominance component motion vector candidate is selected as the selection information 249 by the condition determination table 241 of FIG. 19 . Here, according to Equation 4, the second chrominance component motion vector candidate is,</p><p><maths num="7"><df>(MVC2_x, MVC2_y) = (MV_x/2, MV_y/2 + 1/4) = (0/2, 1/2 + 1/4) = (0, 3/4)</df></maths></p><p>becomes this Then, this value is output as a motion vector 242 of the color difference component in FIG. When this vector (0, 3/4) is applied to the pixel 172 of the reference source bottom field color difference component, the pixel position 173 of the reference top field color difference component is used as the predicted value as the position used for prediction. In Fig. 21, the positional relationship in the vertical direction of each pixel follows the actual case. As can be seen from FIG. 21 , it can be seen that the luminance component motion vectors (0, 1) and the chrominance component motion vectors (0, 3/4) are parallel. Accordingly, the color difference between the luminance component and the color difference component, which has been a problem in the prior art, is solved by the present invention.</p><p>Here, the case of a specific vector has been described in the examples of Figs. 20 and 21. However, by applying the present embodiment to the prediction between other different parity fields, prediction without deviation of luminance and chrominance is possible. </p><p>Also, when the parity of both fields of the reference destination and the reference source is the same, since the above-described color difference does not occur, the configuration is the same as that of the chrominance component motion vector generating unit 220 from the conventional luminance component motion vector shown in FIG. The result of the first chrominance component motion vector means 233 of the present invention with In this case, since the chrominance component motion vector obtained by the present invention is equivalent to the result of the prior art, the description in this embodiment is omitted.</p><p>Also, in another embodiment of the present invention, Equations 3, 4, and 5 become different expressions according to the usage of units of the luminance component motion vector and the chrominance component motion vector. </p><p>22 to 24 are diagrams for explaining another embodiment of the first chrominance component motion vector generating means, the second chrominance component motion vector generating means, and the third chrominance component motion vector generating means in the present invention. </p><p>Here, it is assumed that when the definition of the luminance component motion vector changes by 4, motion in the luminance image for one pixel is indicated, and when the definition of the chrominance component motion vector changes by 8, the motion within the chrominance image for one pixel is represented. When shown, the first chrominance motion vector candidate 262a is generated by the chrominance component motion vector generating means 260a from the luminance motion vector 261a by the following equation, </p><p><maths num="8"><df>(MVC1_x, MVC1_y) = (MV_x, MV_y)</df></maths></p><p>is calculated according to Then, the obtained motion vector candidate 262a of the first color difference is output to the selection unit.</p><p>Further, the motion vector candidate 272a of the second chrominance is obtained by the chrominance component motion vector generating means 270a from the motion vector 271a of the luminance by the following equation, </p><p><maths num="9"><df>(MVC2_x, MVC2_y) = (MV_x, MV_y+2)</df></maths></p><p>is calculated according to Then, the obtained motion vector candidate 272a of the second color difference is output to the selection unit.</p><p>In addition, the third color difference motion vector candidate 282a is obtained by the chrominance component motion vector generating means 280a from the luminance motion vector 281a by the following equation, </p><p><maths num="10"><df>(MVC3_x, MVC3_y) = (MV_x, MV_y-2)</df></maths></p><p>is calculated according to Then, the obtained motion vector candidate 282a of the second color difference is output to the selection unit.</p><p>In addition, although the present embodiment has been described with an AVC FCD as an example, the description herein is only one embodiment and does not limit other embodiments. </p><p>(Annex 1) </p><p>A video encoding apparatus for performing inter-field motion compensation prediction on a video signal composed of a plurality of fields, the video encoding apparatus comprising: </p><p>a plurality of chrominance component motion vector generating means for generating a chrominance component motion vector from a luminance component motion vector; </p><p>selecting means for selecting one of the chrominance component motion vector generating means to be used for generating the chrominance component motion vector by receiving parity of the motion vector reference destination field and the reference source field as inputs; </p><p>A moving picture encoding apparatus, characterized in that a color difference component motion vector generating unit selected by the selection unit generates a predictive vector of a color difference component from motion vector information of luminance information. </p><p>(Annex 2) </p><p>according to Annex 1, </p><p>A chrominance component motion vector generating means for generating a chrominance component motion vector from a luminance component motion vector, comprising: </p><p>first color difference component motion vector generation means selected by the selection means when the reference destination field and the reference source field have the same parity; </p><p>second chrominance component motion vector generation means selected by the selection means when the reference destination field is the top field and the reference source field is the bottom field; </p><p>and a third chrominance component motion vector generating means selected by the selection means when the reference destination field is the bottom field and the reference source field is the top field. </p><p>(Annex 3) </p><p>according to Annex 2, </p><p>The first chrominance component motion vector generating means uses MVy as a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 1 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit,</p><p>MVCy=MVy÷2 </p><p>A moving picture encoding apparatus, characterized in that obtained by </p><p>(Annex 4) </p><p>according to Annex 2, </p><p>The second chrominance component motion vector generating means uses MVy as a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 1 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit,</p><p>MVCy=MVy÷2+0.25 </p><p>A moving picture encoding apparatus, characterized in that obtained by </p><p>(Annex 5) </p><p>according to Annex 2, </p><p>The third chrominance component motion vector generating means uses MVy as a motion vector of a luminance component representing a vertical motion for one pixel of a luminance component of the field image with a value of the vector component as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit,</p><p>MVCy=MVy÷2-0.25 </p><p>A moving picture encoding apparatus, characterized in that obtained by </p><p>(Annex 6) </p><p>according to Annex 2, </p><p>The first chrominance component motion vector generating means uses MVy as a motion vector of a luminance component representing a vertical motion for one pixel of a luminance component of the field image with a value of the vector component as a unit of 4, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit,</p><p>MVCy=MVy </p><p>A moving picture encoding apparatus, characterized in that obtained by </p><p>(Annex 7) </p><p>according to Annex 2, </p><p>The second chrominance component motion vector generating means sets, as MVy, a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 4 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit,</p><p>MVCy=MVy+2 </p><p>A moving picture encoding apparatus, characterized in that obtained by </p><p>(Annex 8) </p><p>according to Annex 2, </p><p>The third chrominance component motion vector generating means sets, as MVy, a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 4 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit, </p><p>MVCy=MVy-2 </p><p>A moving picture encoding apparatus, characterized in that obtained by </p><p>(Annex 9) </p><p>A video decoding apparatus for performing inter-field motion compensation prediction on a video signal composed of a plurality of fields, the video decoding apparatus comprising: </p><p>a plurality of chrominance component motion vector generating means for generating a chrominance component motion vector from a luminance component motion vector; </p><p>selecting means for selecting one of the chrominance component motion vector generating means to be used for generating the chrominance component motion vector by receiving parity of the motion vector reference destination field and the reference source field as inputs; </p><p>A moving picture decoding apparatus, characterized in that a color difference component motion vector generation unit selected by the selection unit generates a predictive vector of a color difference component from motion vector information of luminance information. </p><p>(Annex 10) </p><p>according to Annex 9, </p><p>A chrominance component motion vector generating means for generating a chrominance component motion vector from a luminance component motion vector, comprising: </p><p>first color difference component motion vector generation means selected by the selection means when the reference destination field and the reference source field have the same parity; </p><p>second chrominance component motion vector generation means selected by the selection means when the reference destination field is the top field and the reference source field is the bottom field; </p><p>and a third chrominance component motion vector generating means selected by the selection means when the reference destination field is the bottom field and the reference source field is the top field. </p><p>(Annex 11) </p><p>according to Annex 10, </p><p>The first chrominance component motion vector generating means uses MVy as a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 1 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit,</p><p>MVCy=MVy÷2 </p><p>A moving picture decoding device, characterized in that obtained by </p><p>(Annex 12) </p><p>according to Annex 10, </p><p>The second chrominance component motion vector generating means uses MVy as a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 1 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit,</p><p>MVCy=MVy÷2+0.25 </p><p>A moving picture decoding device, characterized in that obtained by </p><p>(Annex 13)</p><p>according to Annex 10, </p><p>The third chrominance component motion vector generating means uses MVy as a motion vector of a luminance component representing a vertical motion for one pixel of a luminance component of the field image with a value of the vector component as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit,</p><p>MVCy=MVy÷2-0.25 </p><p>A moving picture decoding device, characterized in that obtained by </p><p>(Annex 14) </p><p>according to Annex 10, </p><p>The first chrominance component motion vector generating means uses MVy as a motion vector of a luminance component representing a vertical motion for one pixel of a luminance component of the field image with a value of the vector component as a unit of 4, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit,</p><p>MVCy=MVy </p><p>A moving picture decoding device, characterized in that obtained by </p><p>(Annex 15) </p><p>according to Annex 10, </p><p>The second chrominance component motion vector generating means sets, as MVy, a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 4 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit,</p><p>MVCy=MVy+2 </p><p>A moving picture decoding device, characterized in that obtained by </p><p>(Annex 16) </p><p>according to Annex 10, </p><p>The third chrominance component motion vector generating means sets, as MVy, a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 4 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit,</p><p>MVCy=MVy-2 </p><p>A moving picture decoding device, characterized in that obtained by </p><p>(Annex 17) </p><p>A video encoding/decoding method for performing inter-field motion compensation prediction on a video signal composed of a plurality of fields, the video encoding/decoding method comprising: </p><p>providing a plurality of chrominance component motion vector generating means for generating a chrominance component motion vector from a luminance component motion vector; </p><p>a selection step of selecting one of the chrominance component motion vector generating means to be used for generating the chrominance component motion vector by inputting parity between the reference destination field and the reference source field of the motion vector; </p><p>A program for realizing a moving picture encoding/decoding method in a computer, wherein a predictive vector of a chrominance component is generated from motion vector information of luminance information by means for generating a chrominance component motion vector selected in the selection step. </p><p>(Annex 18) </p><p>according to Annex 17, </p><p>A chrominance component motion vector generating means for generating a chrominance component motion vector from a luminance component motion vector, comprising: </p><p>first chrominance component motion vector generating means selected by the selection step when the reference destination field and the reference source field have the same parity; </p><p>second chrominance component motion vector generating means selected by the selection step when the reference destination field is the top field and the reference source field is the bottom field; </p><p>and a third chrominance component motion vector generating means selected by the selection step when the reference destination field is the bottom field and the reference source field is the top field. </p><p>(Annex 19) </p><p>according to Annex 18, </p><p>The first chrominance component motion vector generating means uses MVy as a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 1 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit,</p><p>MVCy=MVy÷2 </p><p>A program characterized in that obtained by . </p><p>(Annex 20) </p><p>according to Annex 18, </p><p>The second chrominance component motion vector generating means uses MVy as a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 1 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit, </p><p>MVCy=MVy÷2+0.25 </p><p>A program characterized in that obtained by . </p><p>(Annex 21) </p><p>according to Annex 18, </p><p>The third chrominance component motion vector generating means uses MVy as a motion vector of a luminance component representing a vertical motion for one pixel of a luminance component of the field image with a value of the vector component as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 1 as a unit,</p><p>MVCy=MVy÷2-0.25 </p><p>A program characterized in that obtained by . </p><p>(Supplementary 22) </p><p>according to Annex 18, </p><p>The first chrominance component motion vector generating means uses MVy as a motion vector of a luminance component representing a vertical motion for one pixel of a luminance component of the field image with a value of the vector component as a unit of 4, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit,</p><p>MVCy=MVy </p><p>A program characterized in that obtained by . </p><p>(Annex 23) </p><p>according to Annex 18, </p><p>The second chrominance component motion vector generating means sets, as MVy, a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 4 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit,</p><p>MVCy=MVy+2 </p><p>A program characterized in that obtained by . </p><p>(Annex 24) </p><p>according to Annex 18, </p><p>The third chrominance component motion vector generating means sets, as MVy, a motion vector of a luminance component in which the value of the vector component represents a vertical motion for one pixel of the luminance component of the field image with a value of 4 as a unit, and the value of the vector component When MVCy is the motion vector of the color difference component representing the vertical movement of one pixel of the color difference component of the field image with 8 as a unit,</p><p>MVCy=MVy-2 </p><p>A program characterized in that obtained by . </p><p>(Supplementary 25) </p><p>A video encoding/decoding method for performing inter-field motion compensation prediction on a video signal composed of a plurality of fields, the video encoding/decoding method comprising: </p><p>providing a plurality of chrominance component motion vector generating means for generating a chrominance component motion vector from a luminance component motion vector; </p><p>a selection step of selecting one of the chrominance component motion vector generating means to be used for generating the chrominance component motion vector by inputting parity between the reference destination field and the reference source field of the motion vector; </p><p>A moving picture encoding/decoding method characterized by generating a predictive vector of a color difference component from motion vector information of luminance information by means for generating a color difference component motion vector selected in the selection step. </p><p>(Annex 26) </p><p>according to Annex 25, </p><p>A chrominance component motion vector generating means for generating a chrominance component motion vector from a luminance component motion vector, comprising: </p><p>first chrominance component motion vector generating means selected by the selection step when the reference destination field and the reference source field have the same parity; </p><p>second chrominance component motion vector generating means selected by the selection step when the reference destination field is the top field and the reference source field is the bottom field; </p><p>and a third chrominance component motion vector generating means selected by the selection step when the reference destination field is the bottom field and the reference source field is the top field.</p>