JP2009049513A - Moving picture encoding device and moving picture encoding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To select an in-screen prediction mode capable of reducing an operation amount without adding a special circuit block for determining an image pattern. <P>SOLUTION: Differential values from prediction images corresponding to the respective in-truck prediction modes are respectively stored with respect to the luminance signal of an encoding object image. The prediction mode with the smallest differential value is selected as the in-truck prediction mode of the luminance signal. Besides, a previously statistically obtained coefficient is added to the differential values relative to the block size of 16×16 pixels among the differential values of the luminance signal with respect to the respective in-truck prediction modes, so as to perform calculation as cost values with respect to the in-truck prediction mode of a color difference signal. The prediction mode with the smallest cost value is selected as the in-truck prediction mode of the color difference signal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a moving image encoding apparatus and a moving image encoding method, and particularly to a technique suitable for use in real time encoding of a moving image.

  2. Description of the Related Art Conventionally, a digital video camera is well known as a camera-integrated moving image recording apparatus that compresses and records a moving image obtained by photographing a subject, for example. In recent years, since convenience such as random accessibility is high, in a digital video camera, a recording medium to be used is changed from a conventional magnetic tape to a disk medium or a semiconductor memory. However, in general, a disk medium or the like has a small storage capacity and needs to be compressed and encoded more efficiently.

  In addition, with the expectation of high image quality, digital video cameras that handle high-definition video with a large amount of information are being developed. Thus, from another viewpoint, more efficient compression coding is desired. Currently, MPEG is often used as a standard system.

  In recent years, more efficient coding has been studied because of the further improvement of the recordable time on the recording medium and the necessity of coding at a lower bit rate for portable terminals. One of them is H. H.264 (also known as AVC), which requires a larger amount of computation for encoding and decoding than conventional encoding schemes such as MPEG2 and MPEG4, but higher encoding efficiency can be realized. Are known.

  H. In H.264, various ideas have been made to increase the encoding efficiency. One example is in-screen prediction. In the intra prediction, it is possible to effectively suppress the code amount by encoding the difference information with the predicted image generated using the pixel values in the screen near the encoding target block. There are multiple types of intra prediction modes, and it is necessary to select a suitable prediction mode.

  According to the “image encoding device” described in Patent Document 1, a determination unit that divides input image data into blocks each including a plurality of pixels and determines an image pattern of the input image data is provided. In addition, a selection unit that selects a prediction method for generating a predicted pixel value by predicting a pixel value in the same frame using a pixel value in the frame based on the determined image pattern is provided, and an optimal intra prediction mode is provided. Can be selected easily.

JP 2006-005659 A

  As described above, there are a plurality of intra-screen prediction modes, and enormous operations are required to select a suitable mode from the modes. According to the method proposed by Patent Document 1, although it contributes to selecting a suitable intra prediction mode, it is necessary to incorporate a special circuit block for determining an image pattern.

In addition, it is necessary to determine the intra prediction mode for each of the luminance signal and the color difference signal constituting the encoding target block. In particular, when performing encoding processing in real time, there is a problem that a very high speed processor is required and power consumption increases.
In view of the above-described problems, an object of the present invention is to enable selection of an in-screen prediction mode capable of reducing the amount of calculation without adding a special circuit block for determining an image pattern.

  The moving picture coding apparatus according to the present invention divides an image signal composed of a plurality of components into coding blocks that are coding units, and converts the divided coding blocks into prediction blocks that are prediction units. A dividing unit that divides, a predicted image generating unit that generates a predicted image using a pixel value in the vicinity of the predicted block for each prediction block divided by the dividing unit, and a predicted image generated by the predicted image generating unit. Difference value calculating means for calculating a difference value with the predicted image in the screen, encoding means for encoding the difference information generated by the difference value calculating means, components constituting the image signal, and the prediction block Prediction mode determining means for determining a prediction mode according to a combination of the magnitudes of the first and second prediction modes. And determines the mode, and determines a prediction mode from the image signal of the first component relative to the components other than the first component.

  The moving picture coding method of the present invention divides an image signal composed of a plurality of components into coding blocks that are coding units, and also divides the divided coding blocks into prediction blocks that are prediction units. A division step of dividing, a prediction image generation step of generating a prediction image using a pixel value in the vicinity of the prediction block for each prediction block divided in the division step, and a prediction image generated in the prediction image generation step A difference value calculating step for calculating a difference value with the predicted image in the screen, an encoding step for encoding the difference information generated in the difference value calculating step, a component constituting the image signal, and the prediction block A prediction mode determining step for determining a prediction mode according to a combination of the sizes of the image signals. In the prediction mode determination step, the image signal of the first component is included. And it determines the first prediction mode from, and determines a prediction mode for the first component elements from an image signal other than the first component of the.

  The program of the present invention divides an image signal composed of a plurality of components into coding blocks that are coding units, and divides the divided coding blocks into prediction blocks that are prediction units. A prediction image generation step for generating a prediction image using a pixel value in the vicinity of the prediction block for each prediction block divided in the division step; a prediction image generated in the prediction image generation step; and an intra-screen prediction image A difference value calculating step for calculating a difference value, an encoding step for encoding the difference information generated in the difference value calculating step, a component constituting the image signal, and a size of the prediction block A prediction mode determination step for determining a prediction mode according to the combination is executed by a computer. In the prediction mode determination step, the first configuration Determining a first prediction mode from a raw image signal, and causing a computer to determine a prediction mode for a component other than the first component from the image signal of the first component; And

  According to the present invention, it is possible to select a suitable intra-screen prediction mode while reducing the amount of calculation for determining the intra-screen prediction mode, and a highly efficient moving picture encoding device with reduced power consumption. Can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
FIG. 1 shows an H.264 system according to the first embodiment. 1 is a block diagram illustrating a configuration example of a moving image encoding device corresponding to an H.264 encoding scheme.

  As shown 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 vector search unit 103, an inter-frame motion compensation unit 104, and a screen. An inner prediction mode determination unit 105 is provided. Further, an intra-screen prediction unit 120, a switch 106, a subtractor 107, an integer conversion unit 108, a quantization unit 109, an inverse quantization unit 110, and an inverse integer conversion unit 111 are provided. Furthermore, an adder 112, an in-loop filter 113, 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 unit including the code amount control unit 116 is controlled by the system controller 100. That is, the system controller 100 outputs a control command 100a to each part of the entire apparatus via a bus (not shown), and controls operation of the entire apparatus. With such a configuration, the system controller 100 controls the operation of the entire apparatus in accordance with a user instruction output when the user operates the operation unit 11.

Next, an example of a processing procedure performed in the moving picture coding apparatus according to the present embodiment will be described using the flowcharts of FIGS. 1 and 5.
When an image signal is generated by operating the imaging unit 101 to capture an image (step S501), the first frame, the second frame, the third frame,... Are sequentially stored in the frame memory 102. (Step S502).

  In step S503, the image data stored in the frame memory 102 is read out. In this reading, for example, image data is extracted in the order of frames to be encoded, such as the third frame, the first frame, the second frame,.

  Next, the image data taken out from the frame memory 102 is encoded. As an encoding method, there are “intra encoding” in which only image data in a frame is encoded, and “inter encoding” in which encoding is performed including inter-frame prediction. In the present embodiment, H.264, which is one of the standard compression coding systems for moving image data. H.264 is adopted.

  H. In H.264, various devices have been devised in order to increase the encoding efficiency, and one example is in-screen prediction. In intra prediction, the amount of code is suppressed by encoding difference information between a prediction image generated using a pixel value in the screen near the encoding target block and the encoding target block.

  Also, motion vector encoding generates a prediction vector calculated using motion vectors of surrounding motion compensation blocks that have already been encoded for the motion compensation block (processing unit) to be processed. (Step S504). Next, the difference vector between the motion vector to be encoded and the prediction vector is encoded.

  Inter-coding includes a P picture that performs prediction with one reference frame for a motion compensation unit (MC: Motion Compensation) and up to two reference frames for a motion compensation block. There is a B picture that performs prediction. Note that a picture to be subjected to intra coding is called an I picture. The reason why the order of frames to be encoded is different from the order of input frames is to enable temporal prediction (backward prediction) with future frames.

  When intra coding is performed, image data is read out from the frame memory 102 into coding blocks which are coding units, and is input to the intra prediction mode determination unit 105. The intra prediction mode determination unit 105 is a block of a plurality of prediction images generated from an encoding target block and a reconstructed image located in the vicinity of the encoding target block in the same encoded frame that will be described later. Matching is performed on each of them (step S505). Then, the intra prediction mode with the highest correlation is selected and output to the intra prediction unit 120 (step S506).

  The intra-screen prediction unit 120 generates a prediction image according to the intra-screen prediction mode selected by the intra-screen prediction mode determination unit 105 and outputs the prediction image to the switch 106 (step S507). When intra coding is performed, the switch 106 is switched to the intra prediction unit 120 (prediction image within screen), and the intra prediction image is input to the subtractor 107. The subtractor 107 calculates difference information of pixel values between the encoding target block input from the frame memory 102 and the intra-screen prediction image input from the switch 106 and outputs the difference information to the integer conversion unit 108 (step S508). .

  The quantization amount in the quantization unit 109 is calculated (calculated) by the code amount control unit 116 from the feedback of the code amount generated by the entropy encoding unit 115 (step S509). Also, the quantized transform coefficient that is the output of the quantization unit 109 is inversely quantized by the inverse quantization unit 110 (step S510). Further, the inverse integer transform unit 111 performs an inverse integer transform process, which is decoded and a reconstructed image is generated (step S511). And it becomes an input of the intra prediction part 120 mentioned above and the intra prediction mode determination part 105, and is used for the production | generation of an intra prediction image.

  Further, the reconstructed image is subjected to encoding distortion reduction processing by the in-loop filter 113 and then stored in the frame memory 102 as a reference image used in inter-encoding described later (step S512).

  On the other hand, when inter coding is performed, image data of a block serving as a coding unit is read from the frame memory 102 and input to the motion vector search unit 103. At the same time, the motion vector search unit 103 reads a reference image from the frame memory 102 and detects a motion vector from the encoded image and the reference image. The inter-frame motion compensation unit 104 performs motion compensation according to the motion vector, and generates a predicted image.

  When inter coding is performed, the switch 106 is switched to the inter-frame motion compensation unit 104 side (inter prediction image side), and the difference between the encoded image and the prediction image is calculated by the subtractor 107 to generate a difference image. Is done. The difference image calculated by the subtracter 107 is output to the integer conversion unit 108. Other processing is the same as that in the case of the above-described intra coding.

Hereinafter, the operation of the intra prediction mode determination unit 105 will be described in detail with reference to FIG.
FIG. 2 is a block diagram showing a schematic configuration of the intra prediction mode determination unit 105 according to the first embodiment of the present invention.

  As shown in FIG. 2, the intra-screen prediction mode determination unit 105 includes prediction image generation units 201a, 201b,..., 201m, switches 202 and 204, a difference value calculation unit 203, and luminance difference value storage units 205a and 205b. ... with 205m. In addition, a luminance prediction mode determination unit 206, a color difference prediction mode determination unit 207, and the like are provided.

  The image signal is composed of a luminance signal and a color difference signal, and the color difference signals corresponding to 16 horizontal pixels and 16 vertical pixels of the luminance signal have a relationship of 8 horizontal pixels and 8 vertical pixels. As the intra prediction mode, a plurality of intra prediction modes are determined by a combination of the components of the image signal (luminance signal and color difference signal) and the size of the prediction block. A plurality of intra-screen prediction modes are illustrated and represented as “FIGS. 4-1” and “FIG. 4-2”.

  In FIG. 4A and FIG. 4B, the white square represents one pixel of the predicted image, and the hatched square represents one pixel of the peripheral image necessary for generating the predicted image. ing. The arrows in “FIGS. 4-1” and “FIG. 4-2” schematically indicate the prediction directions of the respective prediction modes, and those without an arrow indicate that each pixel of the predicted image is a pixel value of the surrounding image. It shows that it is the average value of.

  “FIG. 4A” represents “Mode 0” to “Mode 8” of “4 × 4 prediction block of luminance signal”. Also, “FIG. 4-2” indicates “mode 0” to “mode 3” of “16 × 16 prediction block of luminance signal” and “mode 0” to “mode of“ 8 × 8 prediction block of color difference signal ”. 3 ".

  The predicted image generation unit 201 a generates a predicted image corresponding to “mode 0” of “16 × 16 predicted block of luminance signal” and outputs the predicted image to the switch 202. The switch 202 is switched to the predicted image generation unit 201 a side, and outputs the predicted image generated by the predicted image generation unit 201 a to the difference value calculation unit 203.

  The difference value calculation unit 203 calculates an input encoding target image (coding block) and a difference value between corresponding pixel values of the predicted image. Then, the calculated difference values of the respective pixels are integrated to calculate a difference value representing the correlation between the encoding target image and the predicted image, and output to the switch 204. The switch 204 is switched to the luminance difference value storage unit 205a side, and the difference value is stored in the luminance difference value storage unit 205a.

  Next, the switch 202 is switched to the predicted image generation unit 201b side. Further, the switch 204 is switched to the luminance difference value storage unit 205b side, and a difference value corresponding to “mode 1” of “16 × 16 prediction block of luminance signal” is calculated and stored in the luminance difference value storage unit 205b. The

  The above operation is repeated while switching the switch 202 and the switch 204, the difference values for all the intra-screen prediction modes for the luminance signal are calculated, and stored in the luminance difference value storage unit corresponding to each prediction mode.

  The difference value corresponding to each prediction mode is input to the luminance prediction mode determination unit 206, and the luminance prediction mode determination unit 206 detects the smallest difference value corresponding to each prediction mode. Then, the prediction mode corresponding to the difference value having the smallest value is newly output to the intra-screen prediction unit 120 as the intra-screen prediction mode that can be used for encoding the luminance signal.

  Also, the luminance prediction mode determination unit 206 detects the smallest difference value with respect to the “16 × 16 prediction block of luminance signal”, and outputs the prediction mode corresponding to the difference value to the color difference prediction mode determination unit 207.

  The chrominance prediction mode determination unit 207 outputs the prediction mode input from the luminance prediction mode determination unit 206 to the intra-screen prediction unit 120 as an intra-screen prediction mode used for encoding the chrominance signal.

Next, an example of a processing procedure for determining an intra-screen prediction mode used for encoding a color difference signal will be described with reference to the flowchart of FIG.
First, in step 601, predicted image generation units 201a to 201m generate predicted images from surrounding images. As described above, the prediction image is generated by first, as the prediction image generation unit 201a, selects a prediction block that is a prediction unit corresponding to “mode 0” of “16 × 16 prediction block of luminance signal” in the vicinity of the prediction block. Generated using pixel values.

In step S602, the difference value calculation unit 203 newly calculates a difference value between the generated predicted image and the encoding target image.
In step S603, the newly calculated difference value is stored in the storage unit.

  Next, in step S604, it is determined whether a prediction image has been generated in all modes. If “YES” as a result of this determination, the process proceeds to step S606. If “NO”, the process proceeds to step S605 to generate a predicted image of the next mode. Specifically, the difference value calculation unit 203 switches the switch 202 so as to select the predicted image generation unit 201b, and switches the switch 204 so as to select the luminance difference value storage unit 205b.

  Next, returning to step S601, as described above, the prediction image generation to the difference value storage processing in step S604 are repeated. By repeatedly performing the processing of step S601 to step S604, a prediction image can be generated for each prediction block corresponding to “mode 0” to “mode 3” of “16 × 16 prediction block of luminance signal”. Accordingly, all predicted images can be generated, and difference values between all predicted images and the encoding target image can be calculated and stored in the luminance difference value storage units 205a to 205m.

  In step S606, the luminance prediction mode determination unit 206 detects the smallest difference value corresponding to each prediction mode. Then, the prediction mode corresponding to the detected difference value having the smallest value is output to the intra prediction unit 120 as the intra prediction mode used for encoding the luminance signal. Also, the luminance prediction mode determination unit 206 detects the smallest difference value with respect to the “16 × 16 prediction block of luminance signal” and outputs the prediction mode corresponding to the difference value to the color difference prediction mode determination unit 207 ( Step S607).

  The chrominance prediction mode determination unit 207 outputs the prediction mode input from the luminance prediction mode determination unit 206 to the in-screen prediction unit 120 as the in-screen prediction mode used for encoding the chrominance signal (step S608).

  By performing the processing as described above, the first prediction mode can be determined from the luminance signal that is the first component among the components of the image signal. In addition, a prediction mode for a color difference signal that is a component other than the first component can be determined from the image signal of the first component.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
The overall configuration of the video encoding device according to the second embodiment is the same as the configuration of the video encoding device according to the first embodiment described above, and the overall operation is also equivalent.
Hereinafter, the operation of the intra prediction mode determination unit 105 will be described in detail with reference to FIG.
FIG. 3 is a block diagram illustrating a schematic configuration of the intra prediction mode determination unit 105 according to the second embodiment of the present invention.

  As shown in FIG. 3, the intra-screen prediction mode determination unit 105 includes prediction image generation units 201 a, 201 b,..., 201 m, switches 202 and 204, a difference value calculation unit 203, and luminance difference value storage units 205 a and 205 b, ..., 205m. Moreover, it has the brightness | luminance prediction mode determination part 206, the color difference prediction mode determination part 207, and adders 210a, 210b, ..., 210m, 211a, 211b, ..., 211m. Further, the luminance cost value storage units 208a, 208b,..., 208m and the color difference cost value storage units 209a, 209b,.

  The predicted image generation unit 201 a generates a predicted image corresponding to “mode 0” of “16 × 16 predicted block of luminance signal” and outputs the predicted image to the switch 202. Immediately after the start of in-screen prediction, the switch 202 is switched to the predicted image generation unit 201 a side, and outputs the predicted image generated by the predicted image generation unit 201 a to the difference value calculation unit 203.

  The difference value calculation unit 203 calculates a difference value between the input encoding target image and each corresponding pixel value of the predicted image, and further adds the calculated difference value of each pixel to predict the encoding target image and the prediction target image. A difference value representing the correlation with the image is calculated and output to the switch 204. The switch 204 is switched to the luminance difference value storage unit 205a side, and the difference value is stored in the luminance difference value storage unit 205a.

Next, the switch 202 is switched to the predicted image generation unit 201b side. Further, the switch 204 is switched to the luminance difference value storage unit 205b side, and a difference value corresponding to “mode 1” of “16 × 16 prediction block of luminance signal” is calculated and stored in the luminance difference value storage unit 205b. The
The above operation is repeated while switching the switch 202 and the switch 204, the difference values for all the intra-screen prediction modes for the luminance signal are calculated, and stored in the luminance difference value storage units 205a to 205m corresponding to each prediction mode. .

  Each difference value is added and calculated by the adders 210a, 210b,... With the weighting factors KYa, KYb,... Corresponding to each prediction mode, and calculated as a cost value corresponding to each prediction mode. The And it memorize | stores in the brightness | luminance cost value memory | storage part 208a, 208b, .... Here, the weight coefficients KYa, KYb,... Are all zero.

  Of the difference values recorded in the luminance difference value storage units 205a, 205b,..., 205m, the difference value for the “16 × 16 prediction block of luminance signal” is processed like a cited publication. . That is, the adders 211a and 211b add the weighting coefficients KCa, KCb,... Corresponding to the respective prediction modes of the color difference signals. And it is memorize | stored in the color difference cost value memory | storage part 209a, 209b, ... as a cost value corresponding to each prediction mode. Here, the weighting factors KCa, KCb,... Give predetermined constants according to the frequency of occurrence of each intra prediction mode of the color difference signal obtained statistically.

  The cost value corresponding to each prediction mode of the luminance signal is input to the luminance prediction mode determination unit 206. The luminance prediction mode determination unit 206 detects the smallest value among the cost values corresponding to each prediction mode, and uses the prediction mode corresponding to the smallest cost value for encoding the luminance signal. The mode is output to the in-screen prediction unit 120.

The cost value corresponding to each prediction mode of the color difference signal is input to the color difference prediction mode determination unit 207. The color difference prediction mode determination unit 207 detects the smallest value among the cost values corresponding to each prediction mode, and uses the prediction mode corresponding to the cost value with the smallest value for intra-screen prediction used for encoding the color difference signal. The mode is output to the in-screen prediction unit 120.
Note that the method of determining the weighting coefficient is not limited to that used in the present embodiment, and a coefficient determined by another method may be used.

(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.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowcharts shown in FIGS. 5 and 6) for executing each step in the above-described video encoding method is directly or remotely transmitted to a system or apparatus. Supply. 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 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 also performs 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 prediction mode determination part in a screen 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 prediction mode determination part in a screen with which the moving image encoder which concerns on the 2nd Embodiment of this invention is provided. It is a figure for demonstrating the prediction mode in a screen, and is a figure showing "mode 0"-"mode 8" of "4 * 4 prediction block of a luminance signal". It is a figure for demonstrating the prediction mode in a screen, "Mode 0" of "16 * 16 prediction block of a luminance signal"-"Mode 3", and "Mode 0" of "8 * 8 prediction block of a color difference signal" It is a figure showing-"mode 3". It is a flowchart explaining an example of the process sequence performed in the moving image encoder of embodiment. It is a flowchart explaining an example of the process sequence which determines the prediction mode in a screen used by encoding of a color difference signal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Operation part 100 System controller 101 Image pick-up part 102 Frame memory 103 Motion vector search part 104 Inter-frame motion compensation part 105 Intra-frame prediction mode determination part 120 In-screen prediction part 106 Switch 107 Subtractor 108 Integer conversion part 109 Quantization part 110 Inverse Quantization unit 111 Inverse integer conversion unit 112 Adder 113 In-loop filter 115 Entropy encoding unit 116 Code amount control unit 117 Recording unit 118 Recording medium 201a to 201m Predicted image generation unit 202, 204 Switch 203 Difference value calculation unit 205a to 205m Luminance difference value storage units 210a to 210m, 211a to 211m Adders 208a to 208m Luminance cost value storage units

Claims (12)

A dividing unit that divides an image signal composed of a plurality of components into coding blocks that are coding units, and divides the divided coding blocks into prediction blocks that are prediction units;
For each prediction block divided by the dividing unit, a prediction image generation unit that generates a prediction image using pixel values in the vicinity of the prediction block;
Difference value calculating means for calculating a difference value between the predicted image generated by the predicted image generating means and the predicted image in the screen;
Encoding means for encoding the difference information generated by the difference value calculating means;
A prediction mode determination unit that determines a prediction mode according to a combination of the constituent elements of the image signal and the size of the prediction block;
The prediction mode determining means determines a first prediction mode from the image signal of the first component, and also sets a prediction mode for components other than the first component from the image signal of the first component. A moving picture encoding apparatus characterized by determining. The prediction image generation means generates a prediction image for each prediction mode that can be used as the prediction mode of the first component for the first component,
The prediction mode determination unit calculates a difference value between the prediction image generated by the prediction image generation unit and the encoding target block, and calculates the calculated difference value and a predetermined constant for each prediction mode. 2. The moving picture encoding apparatus according to claim 1, wherein the calculated value is calculated as a cost value of each prediction mode, and a prediction mode to be used for encoding is determined according to the cost value. .   The prediction mode determination means, for the constituent elements other than the first constituent element, of the constituent elements other than the first constituent element among the respective prediction modes calculated for the first constituent element. Calculate a difference value for a prediction mode that can be used as a prediction mode and a constant determined in advance for the prediction mode of the component, which is different from the constant used when calculating the cost value of the first component The moving picture coding according to claim 1, wherein the calculated cost value is newly calculated, and a prediction mode to be used when coding the constituent element is determined according to the newly calculated cost value. apparatus.   4. The moving image code according to claim 3, wherein the predetermined constant for the prediction mode is a value based on a statistically determined occurrence frequency for each prediction mode of each component. Device.   5. The moving image according to claim 1, wherein a first component of the image signal is a luminance signal, and a component other than the first component is a color difference signal. 6. Encoding device. A dividing step of dividing an image signal composed of a plurality of components into coding blocks that are coding units, and dividing the divided coding blocks into prediction blocks that are prediction units;
For each prediction block divided in the division step, a prediction image generation step for generating a prediction image using pixel values in the vicinity of the prediction block;
A difference value calculating step for calculating a difference value between the predicted image generated in the predicted image generating step and the predicted image in the screen;
An encoding step for encoding the difference information generated in the difference value calculation step;
A prediction mode determination step of determining a prediction mode according to a combination of the constituent elements constituting the image signal and the size of the prediction block;
In the prediction mode determination step, a first prediction mode is determined from the image signal of the first component, and a prediction mode for components other than the first component from the image signal of the first component A moving picture coding method characterized by determining a value. In the predicted image generation step, for the first component, a predicted image is generated for each prediction mode that can be used as a prediction mode of the first component,
In the prediction mode determination step, a difference value between the prediction image generated in the prediction image generation step and the encoding target block is calculated, the calculated difference value, and a constant determined in advance for each prediction mode, 7. The moving picture coding according to claim 6, wherein a value obtained by calculating is calculated as a cost value for each prediction mode, and a prediction mode to be used for coding is determined according to the cost value. Method.   In the prediction mode determination step, for components other than the first component, among the prediction modes calculated for the first component, components other than the first component A difference value for a prediction mode that can be used as a prediction mode of the first component and a constant that is different from the constant used when calculating the cost value of the first component, 7. The moving image code according to claim 6, wherein a calculated cost value is newly calculated, and a prediction mode to be used when the component is encoded is determined according to the newly calculated cost value. Method.   9. The moving image code according to claim 8, wherein the predetermined constant for the prediction mode is a value based on a statistically determined occurrence frequency for each prediction mode of each component. Method.   The moving image according to any one of claims 6 to 9, wherein the first component of the image signal is a luminance signal, and the component other than the first component is a color difference signal. Encoding method. A dividing step of dividing an image signal composed of a plurality of components into coding blocks that are coding units, and dividing the divided coding blocks into prediction blocks that are prediction units;
For each prediction block divided in the division step, a prediction image generation step for generating a prediction image using pixel values in the vicinity of the prediction block;
A difference value calculating step for calculating a difference value between the predicted image generated in the predicted image generating step and the predicted image in the screen;
An encoding step for encoding the difference information generated in the difference value calculation step;
Causing the computer to execute a prediction mode determination step of determining a prediction mode according to a combination of the components constituting the image signal and the size of the prediction block;
In the prediction mode determination step, a first prediction mode is determined from the image signal of the first component, and a prediction mode for components other than the first component from the image signal of the first component A program for causing a computer to execute determination.   A computer-readable recording medium on which the program according to claim 11 is recorded.

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