JP2005123738A - Apparatus and method of image processing, and electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method of image processing and an electronic camera which can attain cost reduction by attaining reduction of circuit scale of an LSI etc. compared with a conventional apparatus, without using a dedicated conversion circuit for format conversion from a moving picture coding system to a still picture coding system. <P>SOLUTION: The image processing apparatus applies frequency conversion and quantization to an acquired moving picture, and a variable length encoder 14 adds additional information to encoded data being intra-encoded in a first encoding system and stores the data into a memory 16. Also, the encoded data taken from the memory 16 are decoded by a variable length decoder 17. In this case, a predetermined frame picture in the moving picture is designated, the decoder 17 decodes the encoded data associated with the frame image, and the encoder 14 encodes its conversion coefficient using a second encoding system and adds the additional information to store the data in a storage apparatus. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus and method for recording a specific frame of a moving image using an MPEG encoding method as a still image using a JPEG encoding method, and more particularly to an image processing device and method suitable for use in an electronic camera.

  In an image compression function of a digital camera that has become widespread in recent years, the JPEG encoding method is widely used as a still image encoding method, and the MPEG encoding method is widely used as a moving image encoding method.

  In the JPEG encoding method, a still image to be encoded is divided into 8 × 8 pixel blocks, and each block is subjected to discrete cosine transform (hereinafter referred to as “DCT”) to generate a transform coefficient block. After that, each transform coefficient in the transform coefficient block is quantized, and the quantized transform coefficients are scanned in a certain order. At this time, a combination of the number of transform coefficients continuously 0 and a value other than 0 for the transform coefficients. On the other hand, a variable length code is assigned and encoded.

  On the other hand, in the MPEG coding system, “intra-frame (intra) coded pictures” are set at a specific interval from the moving image sequence, and the intra-frame coded pictures are set in the same manner as the JPEG coding system. Block division, DCT, and quantization are performed, and the quantized transform coefficient is encoded using a variable length code. For images other than intra-frame coded pictures, motion-compensated inter-frame prediction is performed to generate an “inter-frame prediction (inter) -encoded picture”, and DCT and quantization are performed on the prediction error and quantized. The transform coefficient is encoded using a variable length code.

  As described above, both the MPEG encoding method and the JPEG encoding method are common in that DCT is used, but both the encoded data format, the variable length code used, the quantization method, and the like are different. There is no compatibility between the encoded data. For example, in MPEG, the quantization value can be changed within a picture, but in JPEG, the quantization value is fixed in units of pictures.

  For this reason, when converting an MPEG-encoded intra-frame encoded picture to a JPEG encoding format, the MPEG encoded data is once decoded by the MPEG decoder into an image before encoding, and the decoded image is It is necessary to input to the JPEG encoder and re-encode. For this reason, problems such as degradation of image quality and increase in processing time due to repeated encoding have occurred.

  In contrast to this, an image data processing apparatus as described below (see, for example, Patent Document 1) has been proposed.

  FIG. 7 is a block diagram showing a configuration of a conventional format conversion circuit. According to Patent Document 1, the image data processing device shown in FIG. 7 is an invention relating to the configuration of a format conversion circuit. In the apparatus described in Patent Document 1, the header analyzer 302 analyzes the header of the moving image encoding scheme, and at the same time, the variable length decoder 303 decodes variable length encoded data based on the moving image encoding scheme, After the quantization parameter converter 304 converts the quantization parameter, the header encoder 305 generates a still image encoding system header, and the variable length encoder 306 generates a variable length code based on the still image encoding system. Generate data.

As described above, the apparatus described in Patent Document 1 performs format conversion without performing inverse quantization and inverse orthogonal transform of encoded data at the time of format conversion. Conversion to a still image encoding method is possible.
JP-A-11-289534

  However, when a conventional apparatus as described above is installed in a digital camera, a “dedicated” for converting encoded data of an intra-frame encoded picture encoded by the MPEG encoding method into the JPEG encoding method. Conversion circuit "was necessary. Providing such a dedicated conversion circuit causes an increase in the circuit scale of an LSI on which an image processing apparatus that performs image encoding and decoding is mounted, resulting in an increase in product cost.

  The present invention has been made in consideration of such a situation, and the format conversion from the moving picture coding system to the still picture coding system is performed in an LSI as compared with the conventional apparatus without using a dedicated conversion circuit. An object of the present invention is to provide an image processing apparatus and method, and an electronic camera that can reduce the cost by reducing the circuit scale.

In order to solve the above problems, the present invention provides a moving image acquisition means for acquiring a moving image,
Frequency conversion means for frequency-converting the moving image to obtain a first conversion coefficient;
Quantization means for quantizing the first transform coefficient;
The first transform coefficient quantized by the quantizing means is encoded by using a first encoding format that encodes adaptively using intra coding and inter coding. Encoding means for generating encoded data of:
Generating means for generating first additional information related to the first encoding format and adding the first additional information to the first encoded data;
Storage means for storing the first encoded data to which the first additional information is added;
An image processing apparatus comprising: a decoding unit configured to decode the first encoded data extracted from the storage unit based on the first additional information added to the first encoded data. ,
A frame designating unit for designating a predetermined frame image in the moving image;
The encoding means performs intra encoding on the frame image specified by the frame specifying means;
The decoding means generates a second transform coefficient by taking out and decoding the encoded data for the frame image designated by the frame designation means from the storage means,
The encoding means generates second encoded data by encoding the second transform coefficient using a second encoding format;
The generating means generates second additional information related to the second encoding format and adds the second additional information to the second encoded data;
The storage means stores the second encoded data to which the second additional information is added.

The image processing method according to the present invention includes a moving image acquisition step of acquiring a moving image,
A frame designating step of designating a predetermined frame image in the moving image;
A frequency conversion step of frequency-converting the moving image to obtain a first conversion coefficient;
A quantization step of quantizing the first transform coefficient;
The first transform coefficient quantized in the quantization step is encoded by using a first encoding format in which intra encoding and inter encoding are adaptively used for encoding. A first encoding step for generating encoded data of
Generating a first additional information related to the first encoding format, and adding the first additional information to the first encoded data;
A first storage step of storing the first encoded data to which the first additional information is added in a predetermined storage device;
A decoding step of obtaining a second transform coefficient by extracting and decoding the encoded data related to the frame image specified in the frame specifying step from the first encoded data stored in the storage device When,
A second encoding step of generating second encoded data by encoding the decoded second transform coefficient using a second encoding format;
Generating a second additional information related to the second encoding format and adding the second additional information to the second encoded data; and
A second storage step of storing in the storage device the second encoded data to which the second additional information is added,
In the encoding step, intra encoding is performed on the frame image specified in the frame specifying step.

Furthermore, the present invention is an electronic camera comprising an image processing device having the above characteristics,
Moving image shooting means for shooting a scene;
A liquid crystal display device for displaying a moving image or a still image;
The image acquisition unit acquires a moving image captured by the moving image capturing unit.

  According to the present invention, the format conversion from the moving image encoding method to the still image encoding method is performed by using a circuit for encoding and decoding a still image and a moving image without using a dedicated conversion circuit. Conversion is possible, and it can be realized with a smaller circuit compared to the conventional apparatus, and cost can be reduced. In addition, there is no influence on the processing result due to the elimination of the dedicated conversion circuit, and there is no deterioration in image quality due to repeated orthogonal transformation and quantization as in the conventional apparatus, and format conversion in a short time is possible. .

  Hereinafter, an embodiment of an image processing apparatus that performs encoding and decoding of moving image data and still image data and conversion of an encoding method will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus that performs image encoding and decoding according to an embodiment of the present invention. As shown in FIG. 1, the image processing apparatus according to the present embodiment includes a motion predictor 10, a selector 11, a DCT unit 12, a quantizer 13, a variable length encoder 14, a header generator 15, a memory 16, A header analyzer 17, a variable length decoder 18, an inverse quantizer 19, an IDCT device 20, a motion compensator 21, a frame memory 22 and a control unit 23 are provided. The image processing apparatus according to the present embodiment uses the “JPEG” method as the still image encoding method and the “MPEG” method as the moving image encoding method. Hereinafter, an example of the operation of the image processing apparatus according to the present embodiment will be specifically described with reference to the drawings.

  First, an operation when encoding is performed in the image conversion apparatus according to the present embodiment will be described. FIG. 2 is a flowchart for explaining an operation example when encoding is performed in the image conversion apparatus according to the present embodiment.

  First, when MPEG encoding is performed, the motion predictor 10 detects a motion vector from the input image signal 50 and a reference frame stored in the frame memory 22 to generate an inter-frame difference signal, The inter-frame prediction encoded picture 51 is output (step S11). Next, in response to an instruction from the control unit 23, the selector 11 selects the input image signal 50 when the encoding target is a still image signal or an MPEG intra-frame encoded picture (I picture). Output. On the other hand, when the encoding target is an MPEG inter-frame predictive encoded picture (P picture or B picture), the selector 11 selects and outputs the inter-frame predictive encoded picture 51 (step S12).

  Then, the DCT unit 12 performs a discrete cosine transform on the image signal output from the selector 11 and outputs a transform coefficient (step S13). Further, the quantizer 13 quantizes the transform coefficient based on the quantization table and the quantization scale value designated by the control unit 23. The quantized transform coefficient is output to both the variable length encoder 14 and the inverse quantizer 19 (step S14).

  When the MPEG method is selected as the encoding method and the encoding target is an I picture or a P picture, an inverse quantization by the inverse quantizer 19 is performed on the quantized transform coefficient in order to generate a reference image. (Step S15) and inverse discrete cosine transform by the IDCT unit 20 are performed (Step S16). If the picture decoded by the inverse discrete cosine transform is a P picture (step S17), the motion compensator 21 performs motion compensation using the reference image stored in the frame memory 22 (step S18). The motion compensated picture is output and stored in the frame memory 22 (step S19). On the other hand, if the decoded picture is an I picture (step S17), the picture is stored in the frame memory 22 from the IDCT unit 20 without performing motion compensation (step S19).

  The variable length encoder 14 includes a variable length encoding table corresponding to each of JPEG and MPEG. Therefore, the variable length encoder 14 selects one of the variable length encoding tables based on the encoding method designated by the control unit 23 (step S20), and uses the selected variable length encoding table. The transform coefficient quantized in this way is subjected to variable length coding (step S21). Next, the header generator 15 generates a header necessary for the data format of the encoding method based on the encoding method designated by the control unit 23, and the variable length code output from the variable length encoder 14. The header is added to the digitized data, and is output to the memory 16 and stored (step S22).

  Next, an operation when decoding is performed in the image processing apparatus according to the present embodiment will be described. FIG. 3 is a flowchart for explaining an operation example when decoding is performed in the image processing apparatus according to the present embodiment.

  First, the encoded data stored in the memory 16 is read and input to the header analyzer 17 (step S31). The header analyzer 17 analyzes the header of the input encoded data based on the encoding method designated by the control unit 23, extracts the variable length code, and outputs it to the variable length decoder 18 (step). S32). The variable length decoder 18 includes a variable length decoding table corresponding to each of JPEG and MPEG. Therefore, the variable length decoder 18 selects one of the variable length decoding tables based on the encoding method designated by the control unit 23 (step S33), and the input variable length code is quantized. Decoding into transform coefficients (step S34).

  The quantized transform coefficient is inversely quantized by the inverse quantizer 19 (step S35), and then subjected to inverse discrete cosine transform by the IDCT unit 20 to generate a decoded image signal 52 (step S36). Here, when JPEG decoding is performed (step S37), the decoded image signal 52 is output to the outside of the image processing apparatus of this embodiment (step S39). On the other hand, when MPEG decoding is performed (step S37), if the decoded image signal 52 is an inter-frame difference signal (inter-frame prediction coded picture), motion compensation is performed by the motion compensator 21 (step S37). S38) and output to the outside of the image conversion apparatus according to the present embodiment (step S39). When the decoded image signal 52 is an intra-frame signal (intra-frame encoded picture), it is output as it is as in the case of JPEG decoding (step S39).

  Next, an operation when format conversion from the MPEG encoding method to the JPEG encoding method is performed in the image processing apparatus of the present embodiment will be described. FIG. 4 is a flowchart for explaining an example of format conversion from MPEG to JPEG in the image processing apparatus according to the present embodiment.

  When receiving an instruction for conversion to a still image from the outside during encoding of a moving image (step S41), the control unit 23 performs the following operation. That is, in order to generate an intra-frame coded picture (I picture), the selector 11 selects and outputs the input image signal 50. Further, a quantization scaling value fixed in the picture is designated for the quantizer 13. Further, an MPEG encoding method is designated for the variable length encoder 14 and the header generator 15. Based on this instruction, processing is performed in each unit according to the above-described procedure. That is, the input image signal 50 is subjected to discrete cosine transform by the DCT unit 12, quantized by the quantizer 13 with the quantization scaling value fixed in the picture, and encoded by the variable length encoder 14 in the MPEG frame. A header that is variable-length-encoded as a picture and generated by the header generator 15 is added and then stored in the memory 16 (step S42).

  The encoded data of the MPEG intra-frame encoded picture stored in the memory 16 is stored at a predetermined timing after the encoding of a series of moving image sequences is completed or by using a free time during the moving image encoding. To convert the format to JPEG encoded data. Alternatively, format conversion can be performed by using an input blanking period of frames constituting a moving image.

  Prior to starting the format conversion process, the control unit 23 designates the JPEG encoding method for the variable length encoder 14 and the header generator 15, and the header generator 17 and the variable length decoder 18. In step S43, the MPEG encoding method is designated.

  When the encoded data of the MPEG intra-frame encoded picture is read from the memory 16, the header analyzer 17 and the variable length decoder 18 perform header analysis and variable length decoding on the encoded data, and quantize it. The converted conversion coefficient is generated (step S44). The quantized transform coefficient is input to the variable length encoder 14 and is variable length encoded as JPEG encoded data (step S45), and then the header generator 15 adds a necessary header to the JPEG encoded data. Then, it is output to the memory 16 and stored (step S46).

  As described above, in the image processing apparatus according to an embodiment of the present invention, when a still image conversion instruction is issued, encoding is performed by selecting intra-frame coding at the time of moving image coding and fixing the quantization scaling value. Therefore, the format conversion from MPEG to JPEG can be performed without decoding into an image signal by inverse quantization and inverse discrete cosine transform, and the effect of preventing image quality deterioration due to repeated discrete cosine transform and quantization can be obtained. . Since the format conversion is performed using the variable length encoder 14 and header generator 15 for image encoding, the header analyzer 17 for image decoding, and the variable length decoder 18, the format conversion is performed. There is no need to provide a special circuit, and as a result, format conversion can be realized without increasing the circuit scale.

  According to the present invention, even when an encoding method other than the MPEG encoding method and the JPEG encoding method described above is used, the present invention can be carried out according to the same procedure. In this embodiment, discrete cosine transform (DCT) is used as frequency transform. However, other methods such as discrete Fourier transform (DFT) can be used in the same manner.

  Next, an example of an electronic camera in which the image processing apparatus according to the embodiment of the present invention described above is mounted will be described.

  FIG. 5 is a block diagram illustrating a configuration of an electronic camera in which an image processing apparatus according to an embodiment of the present invention is mounted. The electronic camera according to the present embodiment includes the image processing apparatus 100 described above. Hereinafter, an operation example of the electronic camera according to the present embodiment will be specifically described with reference to the drawings. FIG. 6 is a flowchart for explaining an operation example of the electronic camera according to the embodiment of the present invention.

  When the moving image capturing button 102 is pressed, the electronic camera control unit 103 gives an instruction to start moving image encoding to the image processing apparatus 100 (step S61). Thus, the moving image signal input from the CCD 104 and digitally converted by the A / D converter 105 is input to the image processing apparatus 100, encoded by the MPEG encoding method, and stored in the memory 106 (step S62). ). Note that when the user reproduces the MPEG-encoded moving image after the photographing is completed, the MPEG encoded data is read from the memory 106 and is decoded by the image processing apparatus 100 as described above to the image memory 108. It is transferred and displayed on the LCD 107.

  Here, when the still image shooting button 101 is pressed during moving image shooting, the electronic camera control unit 103 attaches a tag or the like to the frame when the button is pressed among the frames constituting the moving image, and the still image The frame to be converted is designated (step S63). Further, a still image conversion instruction is given to the image processing apparatus 100 after the end of moving image shooting or by using a free time during moving image encoding (step S64). When the still image shooting button 101 is pressed during moving image shooting, the image processing apparatus 100 intra-frame-codes the input moving image signal with the quantization scale value fixed, and stores it in the memory 106. Storing. Therefore, after the moving image shooting is completed or in the idle time during the moving image encoding, the intraframe encoded data with the fixed quantization scale value is read from the memory 106, and the MPEG encoding method is changed to the JPEG encoding method. After the format conversion is executed, it is stored in the memory 106 (step S65). The memory 106 may use the memory 16 inside the image processing apparatus 100 described above.

  As described above, in the electronic camera according to the present embodiment, the image processing apparatus 100 described above is included, so that the circuit scale necessary for the electronic camera can be made smaller than that of the conventional apparatus and the cost can be reduced. As a result, the same image quality degradation and conversion time as those of the conventional apparatus are realized. When the still image shooting button 101 is pressed during moving image shooting, the format conversion from the MPEG encoding method to the JPEG encoding method can be executed, so that the user of the electronic camera can change the picture constituting the moving image during shooting. Any picture can be recorded as a still picture.

  Note that the present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but a device (for example, a copier, a facsimile machine, etc.) composed of a single device You may apply to.

  Also, an object of the present invention is to supply a recording medium (or storage medium) on which a program code of software that realizes the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (or CPU or CPU) of the system or apparatus. Needless to say, this can also be achieved when the MPU) reads and executes the program code stored in the recording medium. In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) or the like running on the computer based on an instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the recording medium is written in a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the case where the CPU or the like provided in the card or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

  When the present invention is applied to the recording medium, program code corresponding to the flowchart described above is stored in the recording medium.

It is a block diagram which shows the structure of the image processing apparatus which performs image coding and decoding which concerns on one Embodiment of this invention. It is a flowchart for demonstrating the operation example when the encoding in the image conversion apparatus which concerns on this embodiment is performed. It is a flowchart for demonstrating the operation example at the time of decoding in the image processing apparatus which concerns on this embodiment. 5 is a flowchart for explaining an example of format conversion from MPEG to JPEG in the image processing apparatus according to the present embodiment. It is a block diagram which shows the structure of the electronic camera which mounted the image processing apparatus which concerns on one Embodiment of this invention. It is a flowchart for demonstrating the operation example of the electronic camera which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the conventional format conversion circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Motion predictor 11 Selector 12 DCT device 13 Quantizer 14 Variable length encoder 15 Header generator 16 Memory 17 Header analyzer 18 Variable length decoder 19 Inverse quantizer 20 IDCT device 21 Motion compensator 22 Frame Memory 23 Control unit 50 Input image signal 51 Inter-frame predictive coded picture 52 Image signal

Claims (14)

Moving image acquisition means for acquiring a moving image;
Frequency conversion means for frequency-converting the moving image to obtain a first conversion coefficient;
Quantization means for quantizing the first transform coefficient;
The first transform coefficient quantized by the quantizing means is encoded by using a first encoding format that encodes adaptively using intra coding and inter coding. Encoding means for generating encoded data of:
Generating means for generating first additional information related to the first encoding format and adding the first additional information to the first encoded data;
Storage means for storing the first encoded data to which the first additional information is added;
An image processing apparatus comprising: a decoding unit configured to decode the first encoded data extracted from the storage unit based on the first additional information added to the first encoded data. ,
A frame designating unit for designating a predetermined frame image in the moving image;
The encoding means performs intra encoding on the frame image specified by the frame specifying means;
The decoding means generates a second transform coefficient by taking out and decoding the encoded data for the frame image designated by the frame designation means from the storage means,
The encoding means generates second encoded data by encoding the second transform coefficient using a second encoding format;
The generating means generates second additional information related to the second encoding format and adds the second additional information to the second encoded data;
The image processing apparatus, wherein the storage unit stores the second encoded data to which the second additional information is added. Inverse quantization means for inversely quantizing the third transform coefficient obtained by decoding the second encoded data by the decoding means with a predetermined quantization parameter;
The image processing apparatus according to claim 1, further comprising: an inverse frequency transform unit that performs inverse frequency transform on the third transform coefficient that has been inversely quantized.   The image processing apparatus according to claim 1, further comprising display means for displaying a moving image or a still image acquired by the inverse frequency conversion means. The encoding means holds an encoding table corresponding to each of the first and second encoding formats;
The decoding means holds a decoding table corresponding to each of the first and second decoding formats;
Designating means for designating a type of an encoding table referred to by the encoding means during the encoding process in the encoding means and a type of a decoding table referred to by the decoding means during the decoding process in the decoding means; The image processing apparatus according to any one of claims 1 to 3, further comprising: The first encoding format is an MPEG encoding format, and the second encoding format is a JPEG encoding format,
The encoding means encodes the moving image using an MPEG encoding format to generate MPEG encoded data, and encodes the frame image using a JPEG encoding format to generate JPEG encoded data. The image processing apparatus according to claim 1, wherein the image processing apparatus is an image processing apparatus. The encoding means performs variable length encoding of the first or second transform coefficient using a variable length encoding table to generate the first or second encoded data;
The image processing according to any one of claims 1 to 5, wherein the decoding unit performs variable-length decoding on the first or second encoded data using a variable-length decoding table. apparatus. The frequency conversion means obtains the first transform coefficient by performing discrete cosine transform on the moving image;
The image processing apparatus according to claim 2, wherein the inverse frequency transform unit obtains a moving image or a still image by performing inverse discrete cosine transform on the third transform coefficient that has been inversely quantized. The frame designating unit obtains a predetermined frame image of the moving image designated during acquisition of the moving image by the moving image obtaining unit;
8. The frame image is decoded after the storage unit stores all the first encoded data generated from the moving image acquired by the moving image acquisition unit. The image processing apparatus according to any one of the above.   The image according to any one of claims 1 to 8, wherein the quantization means fixes a quantization scaling value within a frame with respect to the frame image specified by the frame specification means. Processing equipment. A moving image acquisition step of acquiring a moving image;
A frame designating step of designating a predetermined frame image in the moving image;
A frequency conversion step of frequency-converting the moving image to obtain a first conversion coefficient;
A quantization step of quantizing the first transform coefficient;
The first transform coefficient quantized in the quantization step is encoded by using a first encoding format in which intra encoding and inter encoding are adaptively used for encoding. A first encoding step for generating encoded data of
Generating a first additional information related to the first encoding format, and adding the first additional information to the first encoded data;
A first storage step of storing the first encoded data to which the first additional information is added in a predetermined storage device;
A decoding step of obtaining a second transform coefficient by extracting and decoding the encoded data related to the frame image specified in the frame specifying step from the first encoded data stored in the storage device When,
A second encoding step of generating second encoded data by encoding the decoded second transform coefficient using a second encoding format;
Generating a second additional information related to the second encoding format and adding the second additional information to the second encoded data; and
A second storage step of storing in the storage device the second encoded data to which the second additional information is added,
In the encoding step, the frame image specified in the frame specifying step is intra-encoded. On the computer,
A moving image acquisition procedure for acquiring a moving image;
A frame designation procedure for designating a predetermined frame image in the moving image;
A frequency conversion procedure for frequency-converting the moving image to obtain a first conversion coefficient;
A quantization procedure for quantizing the first transform coefficient;
The first transform coefficient quantized by the quantization procedure is encoded by using a first encoding format that adaptively uses intra encoding and inter encoding. A first encoding procedure for generating encoded data of:
Generating a first additional information related to the first encoding format, and adding the first additional information to the first encoded data;
A first storage procedure for storing the first encoded data to which the first additional information is added in a predetermined storage device;
A decoding procedure for obtaining a second transform coefficient by taking out and decoding the encoded data related to the frame image specified in the frame specifying step from the first encoded data stored in the storage device When,
A second encoding procedure for generating second encoded data by encoding the decoded second transform coefficient using a second encoding format;
Generating a second additional information related to the second encoding format and adding the second additional information to the second encoded data;
A second storage procedure for storing the second encoded data to which the second additional information is added in the storage device;
In the encoding procedure, an intra encoding is executed on the frame image specified in the frame specifying procedure.   A computer-readable recording medium storing the program according to claim 11. An electronic camera comprising the image processing device according to any one of claims 1 to 9,
Moving image shooting means for shooting a scene;
A liquid crystal display device for displaying a moving image or a still image;
The electronic camera, wherein the image acquisition unit acquires a moving image captured by the moving image capturing unit. A video shooting button,
Still image shooting button,
First instruction means for instructing the moving image shooting means to shoot a moving image when the moving image shooting button is pressed;
When the still image shooting button is pressed during moving image shooting, the frame image when the still image shooting button in the moving image data shot by the moving image shooting means when pressed is pressed The electronic camera according to claim 13, further comprising: a second instruction unit that causes the frame designation unit to designate.

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