JP5349904B2 - Moving picture coding apparatus and moving picture coding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a visually excellent playback image even when encoding is performed while setting compressibility high. <P>SOLUTION: A moving image encoding device includes: an encoding means for dividing the image of moving image data into a plurality of blocks, generating a predictive image using images in the past or in future, and encoding a difference between an image to be encoded and the predictive image; a motion vector search means for searching for the motion vector of the block to be encoded while referring to the image in the past or in future as a reference image; a compressibility setting means for setting compressibility in encoding to be performed by the encoding means; and a calculation method change means for changing the method of calculating the motion vector to be implemented by the motion vector search means in accordance with the compressibility in encoding set by the compressibility setting means, thereby performing encoding in which it is difficult to visually recognize image deterioration during playback. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a moving image encoding apparatus and a moving image encoding method, and more particularly to a technique suitable for use in encoding a moving image with a high compression rate.

  2. Description of the Related Art Conventionally, for example, a digital video camera is well known as a camera-integrated moving image recording apparatus that captures a subject and compresses and encodes a moving image obtained thereby to record it on a recording medium. In recent years, recording media have been changed from conventional magnetic tapes to disk media, semiconductor memories, and the like due to high convenience such as random accessibility.

  As a compression method, MPEG2 which can be compressed at a high compression rate by using motion prediction between frames is generally used. H.264 is also used. In such a compression method, compression is realized by reducing information by quantization, and a desired compression rate can be set by controlling the quantization width.

  Since the information is compressed by the method as described above, if the compression rate is increased, more information is lost and the image quality deteriorates. By the way, since a recording capacity of a disk medium, a semiconductor memory, or the like is generally small, a user usually uses the apparatus after judging a trade-off between image quality and recording time.

  That is, if the encoding compression rate is set low and recording is performed with high image quality, the time required for recording on one recording medium is shortened because the recording is performed at a high bit rate. Also, if the encoding compression rate is set high so that recording can be performed for a long time, the information of the original image is largely lost and the image quality deteriorates.

  In view of this, a device has been devised so that deterioration in quality can be suppressed as much as possible even when encoding is performed at a high compression rate. For example, in the following Patent Document 1, when encoding at a high compression rate, inter-frame encoding is one of the two encoding modes of inter-frame encoding and intra-frame encoding that can be selected for each macroblock. Is preferentially selected.

Japanese Patent No. 4000581

  In general, in consideration of human visual characteristics, encoding is performed with a sample rate of the color difference signal lower than that of the luminance signal. As a result, when the compression rate of encoding increases, the luminance signal and the color difference signal should deteriorate to the same extent in terms of signal deterioration. However, if a considerable amount of information is lost due to a high compression ratio, since the sample rate of the color difference signal is low as described above, the influence range of the deterioration of the color difference information extends over a wide range. There is a problem that is very conspicuous.

In the encoding using motion prediction, it is necessary to encode the motion vector itself, but the code amount of the motion vector itself is an amount that is not influenced by the encoding compression rate. For this reason, since the image signal is largely compressed when the compression rate is high, the ratio of the code amount of the motion vector is relatively increased, and the code amount assigned to the image signal is reduced, so that the deterioration of the image is increased. There is also a problem.
The present invention has been made in view of the above-described problems, and it is an object of the present invention to obtain a visually good reproduced image even when encoding is performed with a high compression rate.

  The moving image encoding apparatus of the present invention divides a screen of moving image data into a plurality of blocks, generates a predicted image using past or future images, and encodes a difference between the image to be encoded and the predicted image. A motion image encoding device having encoding means for converting, referring to the past or future image as a reference image and searching for a motion vector of the block to be encoded, and the encoding Compression rate setting means for setting a compression rate of encoding performed by the means, wherein the moving image data is composed of a luminance signal and a color difference signal, and the motion vector search means is for a plurality of motion vector candidates, A pixel difference value between the corresponding block in the reference image and the encoding target block is sequentially calculated for each of the luminance signal and the color difference signal, and the first pixel difference value of the luminance signal is calculated. The sum of the value multiplied by the number and the value obtained by multiplying the pixel difference value of the color difference signal by the second coefficient is the cost for the motion vector candidate, and the motion vector candidate with the minimum cost is the encoding target. And the motion vector search means changes the values of the first coefficient and the second coefficient according to the compression ratio set by the compression ratio setting means. The ratio of the second coefficient to the first coefficient increases as the compression ratio set by the compression ratio setting means increases.

  The moving image encoding method of the present invention divides a screen of moving image data into a plurality of blocks, generates a predicted image using past or future images, and encodes the difference between the image to be encoded and the predicted image. A motion image encoding method including an encoding step of encoding, a motion vector search step of searching for a motion vector of the block to be encoded with reference to the past or future image as a reference image, and the encoding A compression rate setting step for setting a compression rate of encoding performed in the step, wherein the moving image data includes a luminance signal and a color difference signal, and in the motion vector search step, a plurality of motion vector candidates are The pixel difference value between the corresponding block in the reference image and the encoding target block is sequentially calculated for each of the luminance signal and the color difference signal, and the pixel difference value of the luminance signal is calculated. The sum of the value obtained by multiplying the first coefficient and the value obtained by multiplying the pixel difference value of the color difference signal by the second coefficient is set as the cost for the motion vector candidate, and the motion vector candidate having the minimum cost is determined as the cost. The motion vector operates so as to be determined as a motion vector for the block to be encoded, and changes the values of the first coefficient and the second coefficient according to the compression rate set in the compression rate setting step, and the motion vector In the searching step, when the compression rate set in the compression rate setting step is increased, the ratio of the second coefficient to the first coefficient is increased.

According to the present invention, by changing the motion vector calculation method according to the compression rate of encoding, for example, when the compression rate is set high, it is possible to perform encoding while suppressing deterioration of color difference components, It is possible to make it difficult to visually perceive image degradation during reproduction. Accordingly, it is possible to provide a moving image encoding apparatus that can provide a visually reproduced image even when encoding is performed with a high compression rate.
Further, according to another feature of the present invention, for example, even when encoding is performed with a high compression rate, by suppressing the code amount required for the motion vector, the code amount allocated to the image information is relatively increased, Deterioration of the image is suppressed, and a visually good reproduction image can be obtained.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration example of a moving image encoding apparatus 100 according to the first embodiment of the present invention.
In FIG. 1, the moving image encoding apparatus according to the present embodiment includes an imaging unit 101 including a camera unit such as a lens and a CCD, a frame memory 102, a motion prediction unit 103 that performs motion vector search, and a screen for selecting an intra-screen prediction method. An inner prediction unit 104 is included.

  Also, a prediction method selection unit 105, a prediction image generation unit 106, a subtracter 107, an integer conversion unit 108, a quantization unit 109, an inverse quantization unit 110, an inverse, and the like, which select one of motion prediction and intra prediction. An integer conversion unit 111, an adder 112, and an in-loop filter 113 are included.

  Furthermore, an entropy encoding unit 115, a code amount control unit 116, a recording unit 117, and a recording medium 118 are provided. The operation of each component is controlled by the system controller 114. That is, the system controller 114 controls the operation of the entire apparatus, and controls the operation of the entire apparatus in accordance with an instruction from a user as required from an operation unit (not shown).

Next, the encoding process performed at the time of imaging will be described.
The image signal obtained by imaging the subject in the imaging unit 101 is sequentially stored in the frame memory 102 in the order of the first frame, the second frame, the third frame,. Then, the image data is extracted from the frame memory 102 in the order of encoding, such as the third frame, the first frame, the second frame, and so on.

  Next, the encoding method is determined. As a method for encoding moving image data extracted from the frame memory 102, there are “intra coding” for encoding only image data in a frame and “inter coding” for encoding including inter-frame prediction. is there. In inter-coding, a P picture that performs prediction with one reference frame for a motion compensation unit (MC block) and a B picture that performs prediction with up to two reference frames for an MC block. is there. A picture to be subjected to intra coding is called an I picture. The order of frames to be encoded is different from the order of input frames in order to enable prediction (backward prediction) using temporally past or future images.

  When intra coding is performed, image data of a block serving as a coding unit is read from the frame memory 102 and input to the intra prediction unit 104. The intra-screen prediction unit 104 performs block matching between the encoding target block and a plurality of predicted images generated from reconstructed images located near the encoding target block in the same frame described later. Then, an intra prediction image with the highest correlation is selected and output to the prediction method selection unit 105.

  When intra coding is performed, the prediction method selection unit 105 always selects intra prediction and notifies the prediction image generation unit 106 of the selection result. The predicted image generation unit 106 reads the reconstructed image from the frame memory 102 according to the prediction method selected by the prediction method selection unit 105 and generates an intra-screen predicted image. Then, the generated intra prediction image is output to the subtractor 107.

  The above-described intra-screen prediction image and the image data of the encoding target block read from the frame memory 102 are input to the subtracter 107, and a difference image of pixel values between the encoding target block image and the intra-screen prediction image. Is generated. Then, the generated difference image is output to the integer conversion unit 108. The difference image of pixel values input to the integer conversion unit 108 is subjected to integer conversion in the integer conversion unit 108, and then input to the quantization unit 109 and subjected to quantization processing.

  The transform coefficient quantized by the quantization unit 109 is entropy-encoded by the entropy encoding unit 115 and then input to the recording unit 117. Then, the recording unit 117 generates a recording signal for recording on the recording medium and records the recording signal on the recording medium 118.

  The quantization coefficient in the quantization unit 109 is calculated by the code amount control unit 116 from the feedback of the code amount generated by the entropy coding unit 115, the target code amount set by the system controller 114, and the like. That is, the code amount control unit 116 sets the encoding compression rate. The quantized transform coefficient that is the output of the quantization unit 109 is inversely quantized by the inverse quantization unit 110 and subjected to inverse integer transform processing by the inverse integer transform unit 111.

  The signal subjected to the inverse integer conversion processing in the inverse integer conversion unit 111 is output to the adder 112. To the adder 112, the data subjected to the inverse integer conversion output from the inverse integer conversion unit 111 and the difference image output from the subtractor 107 are input. The adder 112 adds these two inputted. The data after the addition becomes a decoded reconstructed image, which is input to the above-described intra-screen prediction unit 104 and used to generate the intra-screen prediction image. The reconstructed image output from the adder 112 is also input to the in-loop filter 113. Then, after processing for reducing coding distortion is performed by the in-loop filter 113, it is stored in the frame memory 102 as a reference image used in inter coding described later.

  On the other hand, when inter coding is performed, moving image data of a block serving as a coding unit is read from the frame memory 102 and input to the motion prediction unit 103. The motion prediction unit 103 reads the reference image from the frame memory 102, detects a motion vector from the encoded image and the corresponding block in the reference image, and notifies the prediction method selection unit 105 of the motion vector.

  When inter coding is performed, motion prediction or intra prediction can be selected for each coding block. The intra-screen prediction unit 104 operates as described above, and notifies the prediction method selection unit 105 of the result of the intra-screen prediction. The prediction method selection unit 105 receives the results of the motion prediction unit 103 and the in-screen prediction unit 104 as input, selects, for example, the prediction method with the smaller difference value, and notifies the prediction image generation unit 106 of the selection.

  The difference between the encoded image and the predicted image is calculated by the subtractor 107 to generate a difference image. The difference image is output to the integer conversion unit 108, and the other processing is the same as in the case of the above-described intra coding.

  Next, the operation of the motion prediction unit 103 will be described in detail with reference to the block diagram of FIG. 2 and the flowchart of FIG. FIG. 2 is a block diagram illustrating a configuration example of the motion prediction unit 103 included in the video encoding device according to the first embodiment of the present invention.

  As shown in FIG. 2, the motion prediction unit 103 of the present embodiment includes a coded image acquisition unit 201 for luminance, a reference image acquisition unit 202 for luminance, a coded image acquisition unit 203 for color difference, and a reference for color difference. An image acquisition unit 204 is included. Further, it includes a coefficient generation unit 205, a motion vector setting unit 206, a cost comparison unit 207, a luminance accumulation unit 208, a color difference accumulation unit 209, and the like. Further, a first adder 211, a second adder 212, a third adder 213, a first multiplier 214, a second multiplier 215, and the like are included. The coefficient generator 205 obtains the compression rate information from the code amount control unit 116 and generates a coefficient having a size corresponding to the set compression rate, thereby changing the motion vector calculation method. It is.

  In the motion prediction unit 103 of the present embodiment configured as described above, when the operation is started, the encoded image acquisition unit 201 for luminance and the encoded image acquisition unit 203 for color difference are encoded target blocks. Are acquired from the frame memory 102 (step S401).

  Next, the motion vector setting unit 206 sequentially sets a motion vector from among a plurality of motion vector candidates to the reference image acquisition unit 202 for luminance and the reference image acquisition unit 204 for color difference (step S402).

  In step S 403, the reference image acquisition units 202 and 204 acquire image data corresponding to the motion vector set by the motion vector setting unit 206 from the frame memory 102.

  The encoded image (luminance) acquired by the luminance encoded image acquisition unit 201 and the reference image (luminance) acquired by the luminance reference image acquisition unit 202 are supplied to the first adder 211. Is done.

  Also, the encoded image (color difference) acquired by the color difference encoded image acquisition unit 203 and the reference image (color difference) acquired by the color difference reference image acquisition unit 204 are supplied to the second adder 212. Is done. Then, a difference is sequentially calculated for each of the luminance and the color difference (step S404).

  The luminance difference value is given to the luminance integration unit 208, and the number of pixels included in the block of the encoding target image is integrated. Also, the color difference difference value is given to the color difference accumulation unit 209, and the number of pixels included in the block of the encoding target image is accumulated (step S405). The pixel difference value accumulated in the luminance accumulation unit 208 is output to the first multiplier 214, and the first coefficient which is the luminance coefficient output from the coefficient generation unit 205 in the first multiplier 214. Multiply by (Ky). Also, the pixel difference value accumulated in the color difference accumulation unit 209 is output to the second multiplier 215, and the second multiplier 215 outputs the second color difference coefficient output from the coefficient generation unit 205. Is multiplied by the coefficient (Kc) (step S406).

  Further, the multiplication result of the first multiplier 214 and the multiplication result of the second multiplier 215 are output to the third adder 213 and added by the third adder 213. The addition result of the third adder 213 becomes a cost value for the set motion vector, and is output to the cost comparison unit 207 (step S407).

  The cost comparison unit 207 stores the cost value of the smallest value calculated so far and the motion vector corresponding to the cost value. Then, when the calculation of the cost values for all the motion vector candidates is completed, the motion vector candidate having the lowest cost among the stored motion vectors is determined as the motion vector for the block to be encoded (step S408). Next, in step S409, it is determined whether or not to end the process. If not, the process returns to step S401 to repeat the above-described process. Further, if the result of determination in step S409 is that the processing is to end, end processing is performed.

  As described above, the coefficient generation unit 205 of the moving image encoding apparatus 100 according to the present embodiment generates a coefficient having a size corresponding to the compression rate notified from the code amount control unit 116. That is, the coefficient is generated so that the ratio of the value of Kc to Ky increases as the compression rate setting increases. Conversely, the coefficient is generated so that the ratio of the value of Kc to Ky becomes smaller as the compression rate setting is lower. That is, according to the moving picture coding apparatus 100 of the present embodiment, when the compression rate set by the code amount control unit 116 is high, the motion vector calculation method is changed, and the motion vector that places importance on the difference of the color difference signals is changed. Thus, the deterioration of the color difference component can be suppressed. Thereby, visual image quality degradation due to a decrease in compression rate can be reduced. On the other hand, when the compression rate is low, the motion vector can be changed so as to determine a motion vector that emphasizes the difference between the luminance signals.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described.
The operation in this embodiment is the same as that of the moving picture encoding apparatus described in the first embodiment except that the operation of the motion prediction unit is different. FIG. 3 is a block diagram illustrating a configuration example of a motion prediction unit included in the video encoding device according to the second embodiment of the present invention.

  The encoded image acquisition unit 301 acquires the moving image data of the encoding target block from the frame memory 102. In addition, the motion vector setting unit 306 sequentially sets a motion vector from the plurality of motion vector candidates to the reference image acquisition unit 302 and the vector code amount calculation unit 309.

  The reference image acquisition unit 302 acquires moving image data corresponding to the set motion vector from the frame memory 102. The obtained encoded image and reference image are supplied to the fourth adder 310 to calculate a difference. Then, the difference calculated by the fourth adder 310 is given to the accumulation unit 308, and the number of pixels included in the block of the encoding target image is accumulated. The vector code amount calculation unit 309 calculates the code amount of the set motion vector itself.

  The coefficient generation unit 305 obtains the compression rate information from the code amount control unit 116 and generates a coefficient having a magnitude corresponding to the set compression rate, thereby changing the motion vector calculation method. Then, the pixel difference value accumulated in the accumulation unit 308 is multiplied by a third coefficient (Kd) as a coefficient for the difference value output from the coefficient generation unit 305 in the multiplier 311. Also, the calculated value output from the vector code amount calculation unit 309 is multiplied by a fourth coefficient (Kv) as a coefficient for the code amount of the motion vector in the multiplier 312. Thereafter, the multiplication result of the multiplier 311 and the multiplication result of the multiplier 312 are added by the adder 313 to obtain a cost value for the set motion vector, which is input to the cost comparison unit 307.

  The cost comparison unit 307 stores the cost value having the smallest value among the cost values calculated so far and the motion vector corresponding to the cost value. When the calculation of the cost values for all motion vector candidates is completed, the stored motion vector is determined as the motion vector for the block to be encoded.

  In accordance with the compression rate notified from the code amount control unit 116, the coefficient generation unit 305 increases the ratio of the value of Kv to Kd as the compression rate increases, and conversely, as the compression rate decreases, the coefficient generation unit 305 increases the value of Kv relative to Kd. A coefficient is generated so that the ratio becomes small. That is, when the compression rate is high, the motion vector calculation method is changed so that the motion vector is determined with an emphasis on the code amount of the motion vector itself, and the generated code amount of the motion vector itself can be suppressed.

(Other embodiments according to the present invention)
Each means constituting the moving picture coding apparatus according to the above-described embodiment of the present invention can be realized by operating a program stored in a RAM or ROM of a computer. This program and a computer-readable recording medium recording the program are included in the present invention.

  In addition, the present invention can be implemented as, for example, a system, apparatus, method, program, storage medium, or the like. Specifically, the present invention may be applied to a system including a plurality of devices. The present invention may be applied to an apparatus composed of a single device.

  According to the present invention, a software program (in the embodiment, a program corresponding to the flowchart shown in FIG. 4) for executing each step in the above-described moving image encoding method is directly or remotely supplied to a system or apparatus. In addition, this includes a case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, and the like.

  Various recording media can be used as a recording medium for supplying the program. For example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD- R).

  As another program supply method, a browser on a client computer is used to connect to an Internet home page. The computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded from the homepage by downloading it to a recording medium such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. Let me. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer may perform part or all of the actual processing. The functions of the above-described embodiments can be realized.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing based on the instructions of the program, and the functions of the above-described embodiments are realized by the processing.

It is a block diagram which shows the structural example of the moving image encoder which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the motion estimation part with which the moving image encoder which concerns on the 1st Embodiment of this invention is provided. It is a block diagram which shows the structural example of the motion estimation part with which the moving image encoder which concerns on the 2nd Embodiment of this invention is provided. It is a flowchart explaining operation | movement of the moving image encoder of embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Moving image encoder 101 Image pick-up part 102 Frame memory 103 Motion prediction part 104 In-screen prediction part 105 Prediction method selection part 106 Prediction image generation part 107 Subtractor 108 Integer conversion part 109 Quantization part 110 Inverse quantization part 111 Inverse integer Conversion unit 112 Adder 113 In-loop filter 114 System controller 115 Entropy encoding unit 116 Code amount control unit 117 Recording unit 118 Recording medium 201 Encoded image acquisition unit for luminance 202 Reference image acquisition unit for luminance 203 Code for color difference Reference image acquisition unit 205 Color difference reference image acquisition unit 205 Coefficient generation unit 206 Motion vector setting unit 207 Cost comparison unit 208 Luminance integration unit 209 Color difference integration unit 301 Encoded image acquisition unit 302 Reference image acquisition unit 305 Coefficient Generation unit 306 Motion vector setting unit 307 Cost ratio Part 308 integrating unit 309 vector code amount calculating section

Claims (18)

A moving image code having an encoding unit that divides a screen of moving image data into a plurality of blocks, generates a predicted image using past or future images, and encodes a difference between the image to be encoded and the predicted image Device.
Motion vector search means for referring to the past or future image as a reference image and searching for a motion vector of the block to be encoded;
Compression rate setting means for setting a compression rate of encoding performed by the encoding means, and the moving image data comprises a luminance signal and a color difference signal,
The motion vector search means sequentially calculates a pixel difference value between a corresponding block in a reference image and the block to be encoded for a plurality of motion vector candidates for each of a luminance signal and a color difference signal. A sum of a value obtained by multiplying the pixel difference value of the luminance signal by a first coefficient and a value obtained by multiplying the pixel difference value of the color difference signal by a second coefficient is a cost for the motion vector candidate; The first coefficient and the first coefficient are operated according to a compression rate set by the compression rate setting means, and the motion vector candidate having the minimum cost is determined as a motion vector for the block to be encoded. Change the value of the coefficient of 2,
The moving picture coding apparatus characterized in that the motion vector search means increases the ratio of the second coefficient to the first coefficient when the compression ratio set by the compression ratio setting means increases. . A moving image encoding apparatus that encodes a luminance component screen and a color difference component screen of moving image data in units of blocks,
When encoding an image of a block to be encoded on the screen of the moving image data, generated from a reference image obtained by decoding the encoded data of the past or future screen of the screen of the block to be encoded Encoding means for encoding a difference between the predicted image and the image of the encoding target block;
Compression rate setting means for setting a compression rate of encoding by the encoding means;
Motion vector determining means for determining a motion vector of the block to be encoded for generating the predicted image;
The motion vector determination means is a pixel difference value of a color difference component between a block in the reference image and the block to be encoded corresponding to a motion vector when the compression ratio of encoding set by the compression ratio setting means is large. Is smaller than the pixel difference value of the color difference component between the block in the reference image corresponding to the motion vector when the compression rate of encoding set by the compression rate setting means is small and the block to be encoded. And determining a motion vector of the block to be encoded.   The motion vector determination means is a pixel difference value of a luminance component between a block in the reference image and a block to be encoded corresponding to a motion vector when the compression ratio of encoding set by the compression ratio setting means is small Is smaller than the pixel difference value of the luminance component between the block in the reference image corresponding to the motion vector when the compression rate of encoding set by the compression rate setting means is large and the block to be encoded. The moving picture encoding apparatus according to claim 2, wherein a motion vector of the encoding target block is determined. A moving image encoding apparatus that encodes a luminance component screen and a color difference component screen of moving image data in units of blocks,
When encoding an image of a block to be encoded on the screen of the moving image data, generated from a reference image obtained by decoding the encoded data of the past or future screen of the screen of the block to be encoded Encoding means for encoding a difference between the predicted image and the image of the encoding target block;
Compression rate setting means for setting a compression rate of encoding by the encoding means;
Motion vector determining means for determining a motion vector of the block to be encoded for generating the predicted image;
The motion vector determining means calculates a pixel difference value between a block in the reference image corresponding to a plurality of motion vector candidates and a block to be encoded for each of a luminance component and a color difference component of the moving image data. ,
The motion vector determination unit is configured to calculate the color difference component when the compression rate set by the compression rate setting unit is large and when the compression rate set by the compression rate setting unit is small. A video encoding apparatus, wherein the motion vector of the block to be encoded is determined with emphasis on the pixel difference value of the encoding target block.   The motion vector determination unit is configured to calculate the luminance component when the compression rate set by the compression rate setting unit is small and when the compression rate set by the compression rate setting unit is large. 5. The moving picture coding apparatus according to claim 4, wherein the motion vector of the block to be coded is determined with emphasis on the pixel difference value.   The motion vector determination unit is configured to calculate the color difference component when the compression rate set by the compression rate setting unit is large and when the compression rate set by the compression rate setting unit is small. 6. The moving picture coding apparatus according to claim 4, wherein the motion vector of the block to be coded is determined from a motion vector having a smaller pixel difference value.   The motion vector determination unit is configured to calculate the luminance component when the compression rate set by the compression rate setting unit is small and when the compression rate set by the compression rate setting unit is large. 7. The moving picture encoding apparatus according to claim 4, wherein a motion vector of the encoding target block is determined based on a motion vector having a smaller pixel difference value. A moving image encoding device for encoding moving image data,
When encoding an image of a block to be encoded on the screen of the moving image data, generated from a reference image obtained by decoding the encoded data of the past or future screen of the screen of the block to be encoded Encoding means for encoding a difference between the predicted image and the image of the encoding target block;
Compression rate setting means for setting a compression rate of encoding by the encoding means;
Motion vector determining means for determining a motion vector for generating the predicted image;
The motion vector determination unit calculates a pixel difference value between a block in the reference image corresponding to a plurality of motion vector candidates and a block to be encoded for each of a luminance signal and a color difference signal of the moving image data. ,
Determining a motion vector for the block to be encoded based on the calculated pixel difference value of the luminance signal and the pixel difference value of the color difference signal;
The motion vector determination unit selects a motion vector candidate having a smaller pixel difference value of the color difference signal when the compression rate of the encoding set by the compression rate setting unit is larger than when the compression rate of the encoding is small. A moving picture coding apparatus, characterized in that it is determined as a motion vector for the block to be coded.   The motion vector determination unit selects a motion vector candidate whose pixel difference value of the luminance signal is smaller when the compression rate of the encoding set by the compression rate setting unit is smaller than when the compression rate of the encoding is large. 9. The moving picture coding apparatus according to claim 8, wherein the moving picture coding apparatus is determined as a motion vector for the block to be coded. A moving image encoding device for encoding moving image data,
When encoding an image of a block to be encoded on the screen of the moving image data, generated from a reference image obtained by decoding the encoded data of the past or future screen of the screen of the block to be encoded Encoding means for encoding a difference between the predicted image and the image of the encoding target block;
Compression rate setting means for setting a compression rate of encoding by the encoding means;
Motion vector determining means for determining a motion vector for generating the predicted image;
The motion vector determination unit calculates a pixel difference value between a block in the reference image corresponding to a plurality of motion vector candidates and a block to be encoded for each of a luminance signal and a color difference signal of the moving image data. ,
Determining a motion vector for the block to be encoded based on the calculated pixel difference value of the luminance signal and the pixel difference value of the color difference signal;
The motion vector determination unit determines a motion vector candidate whose code amount of the motion vector itself is smaller when the compression rate of the encoding set by the compression rate setting unit is larger than when the compression rate of the encoding is small. A moving picture coding apparatus, characterized in that it is determined as a motion vector for a block to be coded.   The motion vector determination unit encodes a motion vector candidate having a smaller pixel difference value when the compression rate of the encoding set by the compression rate setting unit is smaller than when the compression rate of the encoding is large. 11. The moving picture coding apparatus according to claim 10, wherein the moving picture coding apparatus is determined as a motion vector for a target block.   A program that causes a computer to operate as each means according to any one of claims 1 to 11.   A computer-readable storage medium storing the program according to claim 12. A moving picture code having a coding step of dividing a screen of moving picture data into a plurality of blocks, generating a predicted picture using past or future pictures, and coding a difference between the picture to be coded and the predicted picture A method of
A motion vector search step of referring to the past or future image as a reference image and searching for a motion vector of the block to be encoded;
A compression rate setting step for setting a compression rate of encoding performed in the encoding step, and the moving image data includes a luminance signal and a color difference signal,
In the motion vector search step, for a plurality of motion vector candidates, pixel difference values between a corresponding block in a reference image and the block to be encoded are sequentially applied to each of a luminance signal and a color difference signal. A sum of a value obtained by multiplying the pixel difference value of the luminance signal by a first coefficient and a value obtained by multiplying the pixel difference value of the color difference signal by a second coefficient is a cost for the motion vector candidate; The first coefficient and the first coefficient are operated according to a compression rate set in the compression rate setting step, and the motion vector candidate having the minimum cost is determined as a motion vector for the block to be encoded. Change the value of the coefficient of 2,
In the motion vector search step, when the compression rate set in the compression rate setting step is high, the ratio of the second coefficient to the first coefficient is increased. . A moving image encoding method for encoding a luminance component screen and a color difference component screen of moving image data in block units,
When encoding an image of a block to be encoded on the screen of the moving image data, generated from a reference image obtained by decoding the encoded data of the past or future screen of the screen of the block to be encoded An encoding step for encoding a difference between the predicted image and the image of the encoding target block;
A compression rate setting step for setting a compression rate of encoding in the encoding step;
A motion vector determining step for determining a motion vector of the encoding target block for generating the predicted image,
In the motion vector determination step, the pixel difference value of the color difference component between the block in the reference image and the block to be encoded corresponding to the motion vector when the compression rate of encoding set in the compression rate setting step is large Is smaller than the pixel difference value of the color difference component between the block in the reference image corresponding to the motion vector when the compression rate of encoding set in the compression rate setting step is small and the block to be encoded. And determining a motion vector of the block to be encoded. A moving image encoding method for encoding a luminance component screen and a color difference component screen of moving image data in block units,
When encoding an image of a block to be encoded on the screen of the moving image data, generated from a reference image obtained by decoding the encoded data of the past or future screen of the screen of the block to be encoded An encoding step for encoding a difference between the predicted image and the image of the encoding target block;
A compression rate setting step for setting a compression rate of encoding in the encoding step;
A motion vector determining step for determining a motion vector of the encoding target block for generating the predicted image,
In the motion vector determination step, a pixel difference value between a block in the reference image corresponding to a plurality of motion vector candidates and a block to be encoded is calculated for each of a luminance component and a color difference component of the moving image data. ,
In the motion vector determination step, when the encoding compression rate set in the compression rate setting step is large, the calculated color difference component is more than when the encoding compression rate set in the compression rate setting step is small. A moving picture encoding method, wherein the motion vector of the encoding target block is determined with emphasis on the pixel difference value of the encoding target block. A moving image encoding method for encoding moving image data,
When encoding an image of a block to be encoded on the screen of the moving image data, generated from a reference image obtained by decoding the encoded data of the past or future screen of the screen of the block to be encoded An encoding step for encoding a difference between the predicted image and the image of the encoding target block;
A compression rate setting step for setting a compression rate of encoding in the encoding step;
A motion vector determination step for determining a motion vector for generating the predicted image, and the motion vector determination step corresponds to a plurality of motion vector candidates for each of the luminance signal and the color difference signal of the moving image data. Calculating a pixel difference value between the block in the reference image and the block to be encoded;
Determining a motion vector for the block to be encoded based on the calculated pixel difference value of the luminance signal and the pixel difference value of the color difference signal;
In the motion vector determination step, when the compression rate of the encoding set in the compression rate setting step is large, a motion vector candidate whose pixel difference value of the color difference signal is smaller than when the compression rate of the encoding is small. A moving picture coding method, wherein the motion vector is determined as a motion vector for the block to be coded. A moving image encoding method for encoding moving image data,
When encoding an image of a block to be encoded on the screen of the moving image data, generated from a reference image obtained by decoding the encoded data of the past or future screen of the screen of the block to be encoded An encoding step for encoding a difference between the predicted image and the image of the encoding target block;
A compression rate setting step for setting a compression rate of encoding in the encoding step;
A motion vector determining step for determining a motion vector for generating the predicted image,
In the motion vector determination step, a pixel difference value between a block in the reference image corresponding to a plurality of motion vector candidates and a block to be encoded is calculated for each of a luminance signal and a color difference signal of the moving image data. ,
Determining a motion vector for the block to be encoded based on the calculated pixel difference value of the luminance signal and the pixel difference value of the color difference signal;
In the motion vector determination step, when the compression rate of the encoding set in the compression rate setting step is large, the motion vector candidate having a smaller code amount of the motion vector itself than when the compression rate of the encoding is small A moving picture coding method characterized by determining a motion vector for a block to be coded.

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