JP2004342192A - Data recording device and recording method, and digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reproduce the recorded image data with a personal computer without finalizing or without incorporating a UDF reader. <P>SOLUTION: A CD-RW disk is initialized. The number of files to be written is decided based on a fixed image size designated by a user, a dummy file is recorded in a fixed directory structure and a file size, then the ISO9660 information is recorded, and the reading-in and reading-out are recorded. A mark indicating incomplete photographing is recorded in accessory information such as an Exif tag. Then, photographed image data is overwritten in a dummy file indicated by an incomplete photographing mark. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data recording device and a recording method using a rewritable disk-shaped recording medium, and a digital camera.
[0002]
[Prior art]
As a method of writing data to a CD-R / RW (Compact Disc-Recordable / ReWritable) disc, three types of track-at-once, disc-at-once, and packet write are known. Track-at-once is a method of writing data to be saved as a unit in a track unit. An operation called finalization is necessary so that data written in track units can be read by a CD-ROM drive. That is, after writing necessary data in track units (it may be written in a plurality of tracks), it is necessary to create management information of ISO9660 and close the session (write lead-in and lead-out). . Additional writing can be performed on the disk in this state. For example, in a case where new additional recording is performed by track-at-once, it is necessary to perform the above-mentioned finalizing operation again after performing additional recording of data. When performing the finalizing operation, it is necessary to perform the finalizing operation again. In addition, when the finalizing operation is performed, by setting a write parameter so as to prohibit further additional writing, an additional writing prohibition mark is recorded and additional writing cannot be performed. A CD-R disc recorded by track-at-once can be read by basically any CD-ROM (Compact Disc-Read Only Memory) drive by performing an appropriate finalizing operation.
[0003]
The disc-at-once method is a method of writing from lead-in to lead-out at once. Therefore, only a new disk can be used for writing at disk-at-once, and once data has been written, no more data can be recorded and data cannot be modified. Can be used for data distribution and permanent storage.
[0004]
The packet write method is a method of dividing data to be recorded using a UDF (Universal Disc Format) format into units called packets and storing the data. There are two types of packet writing methods. There are a random write method and a sequential write method. The random write method is a method in which a disk is managed using an address management bitmap, and writing is performed for each unit, and the write address does not become monotonically increasing or decreasing, but becomes more random at times. It will be. Sequential write is a method in which data is written in one direction from the inner circumference to the outer circumference of a disk. Generally, in the random write method, the packet length is fixed length (64 kbytes), and the sequential write is performed in a variable length. CD-R discs, once recorded, cannot be written again even if data is erased. Therefore, a sequential write method is adopted. In the case of a CD-RW disc, data can be repeatedly written in the same place. , Random write and sequential write. In addition, packet writing requires packet writing software, and also requires software for reading. (Excluding the case where the disc is finalized by the sequential write method) Further, when recording by packet writing, it is necessary to first initialize the CD-R / RW disc. After initialization, you can easily record and delete data simply by dragging and dropping files on the screen of My Computer or Explorer.
[0005]
In order to read data from a CD-RW disc recorded by the packet write method using a CD-ROM drive of another Windows (registered trademark) 95/98 personal computer, two methods are possible. One is a method of reading data by incorporating read-only software such as a UDF reader that can understand the UDF format. Another method is to perform a finalizing process, close the session, and create a database in which information compatible with ISO9660, which is a standard that defines the volume and file structure of the CD-ROM, is written. In this case, data can be read by the CD-ROM drive without doing anything. The session is closed by recording the lead-in and lead-out areas.
[0006]
The file structure of the CD-ROM is described in the following document.
[0007]
[Non-patent document 1]
Heitaro Nakajima, one other, "Illustrated Compact Disc Reader (Revised 3rd Edition)", March 25, 2001, Ohmsha, p. 146-151
[0008]
[Problems to be solved by the invention]
The above-described method is to use a digital camera having a CD-RW disc as a storage medium to take out the photographed CD-RW disc and import the data on the CD-RW disc to a personal computer, so as to finalize the data or to execute the software to the personal computer. It required installation and was very inconvenient in terms of time and media capacity.
[0009]
Therefore, an object of the present invention is to provide a data recording apparatus and a recording method which can quickly capture an image with a personal computer without performing a finalizing operation, and can capture an image without installing software, and a digital camera. Is to provide.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention of claim 1 provides a data recording device using a rewritable disk-shaped recording medium,
Record management information that defines a predetermined fixed directory structure and file size,
Record a plurality of dummy files having a file size and a directory structure defined by management information,
Record lead-in and lead-out for management information and dummy file,
This is a data recording device in which a recording image file is overwritten on a dummy file.
[0011]
The invention according to claim 5 is a data recording method using a rewritable disk-shaped recording medium,
Recording management information defining a predetermined fixed directory structure and file size;
Recording a plurality of dummy files having a file size and a directory structure defined by management information;
Recording lead-in and lead-out for management information and dummy files;
Overwriting a dummy file with a recording image file.
[0012]
According to a ninth aspect of the present invention, there is provided a digital camera which records captured image data on a rewritable disc-shaped recording medium,
An image sensor, a signal processing unit for processing an image signal generated by the image sensor, a buffer memory for storing an image signal from the signal processor, and recording of captured image data on an initialized disk-shaped recording medium Recording means, and a control device,
The initialization process is
Record management information that defines a predetermined fixed directory structure and file size,
Record a plurality of dummy files having a file size and a directory structure defined by management information,
It records lead-in and lead-out for management information and dummy files,
This is a digital camera in which a captured image file is overwritten on a dummy file.
[0013]
According to the present invention, a dummy file having a fixed file size is recorded, management information such as a CD-ROM volume and information conforming to ISO9660 which is a file structure is recorded, and further, lead-in and lead-out are recorded. Such initialization processing is performed, and the image file to be recorded is overwritten on the dummy file. The disc-shaped recording medium after the recording conforms to the standard of ISO9660 and can be read by a personal computer having a CD-ROM drive.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described. Referring first to FIG. 1, an outline of ISO 9660 (Information processing-Volume and file structure of CD-ROM for information interchange) will be given first. ISO9660 is an international standard that defines the volume and file structure of a CD-ROM. For a CD-ROM disc that adopts ISO9660, a logical block number (LBN) is set in units of 2 kB immediately after a lead-in area on the inner circumference of the disc. Are allocated in order from 0. The position of LBN = 0 corresponds to the position of 00:02:00 frame of the audio CD.
[0015]
As shown in FIG. 1, LBN = 0 to 15 is defined as a system area. The range from LBN = 16 to the value obtained by subtracting 150 from the value indicating the end of the data area is the range in which the data of the CD-ROM exists. LBN = 16 is the first position, and information starting from LBN = 16 is read from a CD-ROM disc having the file structure of ISO9660.
[0016]
Information starting from LBN = 16 is called a volume descriptor (VD: volume descriptor). Volume descriptors are roughly divided into five types of descriptors, and the most important one is called a main volume descriptor (PVD). FIG. 1 assumes a hierarchical structure in which file 1 and subdirectory 1 exist for the root directory, and file 2 exists for subdirectory 1.
[0017]
The main volume descriptor (PVD) includes a VD type, file format identification, volume size, CD-ROM number, logical block size, path table size, path table address 1, path Information such as the address 2 of the table and the root directory record is included. The attributes of the volume, the position of the root directory, the position of the path table, and the number of volumes are specified by the main volume descriptor (PVD).
[0018]
Further, the volume descriptor includes a sub-volume descriptor (SVD), a volume partition descriptor, a start record, and a volume descriptor set terminator. In the example of FIG. 1, LBN = V is the position of the path table, the entity of the root directory exists at LBN = W, the entity of file 1 exists at LBN = X, and the entity of directory 1 exists at LBN = Y. It indicates that the file 2 exists at LBN = Z.
[0019]
FIG. 2 shows an example of the configuration of a digital camera to which the present invention is applied. Subject light is incident on an image sensor, for example, a CCD (Charge Coupled Device) 1 via a lens device denoted by reference numeral 1. An image signal of the CCD 1 is supplied to the sample and hold circuit 3. The sample hold circuit 3 performs, for example, correlated double sampling. An output signal of the sample hold circuit 3 is supplied to an A / D converter 4 and converted into a digital image signal. The output digital signal of the A / D converter 4 is supplied to the imaging signal processing unit 5, and undergoes processing such as conversion from RGB signals to YUV signals, gamma correction, and the like.
[0020]
Reference numeral 6 denotes a CPU (Central Processing Unit) for system control and a compression encoder for image data. For example, the CPU 6 encodes JPEG (Joint Photographic Experts Group). A detection signal of the shutter button detector 7 is input to the CPU 6, and a display device such as an LCD (Liquid Crystal Display) 8 is connected to the CPU 6. The LCD 8 is used to display an image at the time of imaging and determine an angle of view, is used to display a captured image, and is used to display an operation menu. Further, although not shown, an input device such as a key is connected to the CPU 6.
[0021]
A buffer RAM (Random Access Memory) 9, a ROM (Read Only Memory) 10 storing a program, and a drive controller 11 are connected to a CPU bus of the CPU 6. The drive controller 11 is a block that controls a disk drive. The disk drive is configured to rotate a writable optical disk, for example, a CD-R / W disk 12, by a spindle motor 13. The CD-R / W disc 12 is not limited to a disc having a diameter of 12 cm, and a disc having a diameter of 8 cm can be used.
[0022]
In the digital camera shown in FIG. 2, when a shutter button is pressed, one digital image is fetched into the buffer RAM 9, compression-encoded by the CPU 6, and a compressed image compressed by, for example, JPEG is generated. Is stored in the buffer RAM 9. The compressed image is supplied to the disk drive via the drive controller 11 and written on the CD-RW disk 12 by a user's switch operation or a program. The writing process to the CD-RW disc 12 is performed by using the packet write method or the track-at-once method.
[0023]
In order to use the CD-RW disc 12 in the digital camera described above, the CD-RW disc 12 needs to be initialized. The initialization is performed by a personal computer equipped with a digital camera or a CD-RW drive and incorporating dedicated software bundled with the digital camera. When performing the initialization operation of the CD-RW disc, the user sets a picture size (for example, 1600 × 1200) to be photographed, and the camera uniquely determines a file size (for example, 1 Mbyte) in the designated picture size. Thus, the size A of each image area is determined. The number B of shootable images is determined by the capacity of the medium. A plurality of image sizes to be photographed are prepared, and the user can select a size other than those described above.
[0024]
After that, the CD-RW disc 12 is initialized. At this time, data is written as follows.
[0025]
In the lead-in area, information on the created track is written in accordance with the CD-RW standard (Orange Book). This information is generally called TOC (Table Of Contents). In the track 1, a directory structure, a file name, a recording date, a file size A, etc. of each image are written using a fixed value determined first in conformity with the ISO9660 format. Since the information portion compatible with ISO9660 is not rewritten at the time of shooting, the file name, file creation date and time, file size, and the like are fixed by the data written here. In the following, the term ISO9660 information is used to mean information compatible with ISO9660.
[0026]
On track 2, B image files are written based on the information actually determined on track 1. As a writing format, B tracks may be written in one track by packet writing, or if B <98, a dummy file may be written in units of one track. B <98 is a condition necessary for the track number to have a maximum value of 99. However, if the dummy file is written in units of one track, a waste occurs by the pre-gap between tracks.
[0027]
The image file stored in advance is a JPEG image file that can be easily identified as an image that has not been shot when captured by a personal computer, that is, a dummy image. For example, the image data is entirely black image data. It should be noted that when read by a personal computer immediately after initialization, a dummy image file can be viewed.
[0028]
Also, by storing JPEG data in the Exif file format, additional information on whether or not the image has been shot and information on the size A have been added by using a vendor-unique tag in the Exif tag as attached information. deep. Exif is an image file format standard for digital still cameras. Note that this tag also has an area for recording information such as the shooting date and time, and the accurate shooting date and time can be stored using this area. On a set such as a digital camera, the shooting date and time in the Exif tag may be displayed instead of using the file creation date and time of the ISO9660 information. In the lead-out area, recording is performed according to the CD-RW standard (Orange Book).
[0029]
FIG. 3A shows an example of the state of the disk at the end of the initialization. This shows a case where all dummy files (image 1 to image N) are written in one track (track 2) by the packet write method. FIG. 3B shows another example of the state of the disc at the end of the initialization. FIG. 3B shows a case where data is written to another track for each dummy file, that is, a case where a dummy file is written by track-at-once. In each image area, the size of each image area is equal to A.
[0030]
FIG. 4 is a flowchart showing the flow of the initialization operation. Starting from step S1, in step S2, one file size is determined from the image size specified by the user (for example, 1600 × 1200). In step S3, the number of shots is determined from the media capacity. The calculation for obtaining the number of shots is adjusted according to the writing method. In step S4, a file name / directory structure is determined. Since the embodiment is a digital still camera, the still image file has a file arrangement and a file format according to the camera file system standard DCF (Design rule for Camera File system).
[0031]
In step S5, track 1 for writing ISO9660 information is reserved. In step S6, a dummy file having the determined file size is created. The Exif file format is used as an example. In addition, a mark indicating non-photographing is recorded using a tag that can be used freely by a manufacturer among Exif tags. Further, the dummy image file desirably has a content that can be identified as a dummy at a glance. As described above, for example, an image file whose entire surface is black is used.
[0032]
In step S7, a dummy file is written to the second and subsequent tracks. The writing method is arbitrary, and may be packet writing or track-at-once. In step S8, it is determined whether the process has been repeated for the number of images determined in step S3. If it has not been repeated for the number of shots, the process returns to step S6 (creation of a dummy file).
[0033]
If it is determined in step S8 that the number of shots has been repeated, then in step S9, the ISO9660 information is written to the reserved track 1 with the written file name / directory structure. Then, the session is closed by appropriately writing the lead-in area (TOC) and the lead-out area.
[0034]
FIG. 5 shows an example of ISO9660 information set at the time of initialization when a dummy file is written by the packet write method. FIG. 5 shows an example of a still image file format conforming to the DCF standard. A DCF image root directory having a directory name DCIM (Digital Camera Images) exists immediately below the root directory. A DCF directory exists immediately below DCIM. The DCF directory is a directory for storing DCF objects.
[0035]
In FIG. 5, a directory of 100MSDCF is shown. A plurality of still image files DSC00001. JPG, DSC00002. JPG,... Exist. In this example, DSC represents a still image file from a digital still camera, and the extension JPG represents a JPEG format file.
[0036]
An example of the ISO9660 information when files are stored in the directory structure as described above will be described. LBN = 0 to 15 is defined as a system area. The range from LBN = 16 to the value obtained by subtracting 150 from the value indicating the end of the data area is the range in which the data of the CD-ROM exists. LBN = 16 is the first position, and information starting from LBN = 16 is read from a CD-ROM disc having the file structure of ISO9660.
[0037]
Information starting from LBN = 16 is called a volume descriptor (VD: volume descriptor). Volume descriptors are roughly divided into five types of descriptors, and the most important one is called a main volume descriptor (PVD).
[0038]
The main volume descriptor (PVD) includes a VD type, file format identification, volume size, CD-ROM number, logical block size, path table size, path table address 1, path Information such as the address 2 of the table and the root directory record is included. The attributes of the volume, the position of the root directory, the position of the path table, and the number of volumes are specified by the main volume descriptor (PVD).
[0039]
Further, the volume descriptor includes a sub-volume descriptor (SVD), a volume partition descriptor, a start record, and a volume descriptor set terminator. In the example of FIG. 1, LBN = A is the position of the path table, the root directory entity exists at LBN = B, the DCIM directory entity exists at LBN = C, and the 100MSDCF directory entity exists at LBN = D. Exists. Up to this directory of 100MSDCF is recorded as track 1 by track-at-once.
[0040]
Next, a plurality of dummy files DSC00001. JPG, DSC00002. JPG, ... are written. The directory of 100MSDCF indicates that the substance of each file exists at LBN = E, LBN = F, LBN = G,.
[0041]
FIG. 6 shows an example of ISO9660 information set when a dummy file is recorded by the track-at-once method at the time of initialization. The directory structure is the same example as in FIG. Recording necessary information on track 1 by track-at-once is the same as in the example of FIG. When recording a dummy file, a dummy file is written for each of track 3, track 4,.
[0042]
Next, the disk information initialization process controlled by the CPU 6 will be described with reference to the flowchart in FIG. In step S21, a general initialization operation performed when a CD-RW disc is set in the digital camera is performed. For example, the TOC of the lead-in area of the set disc is read. In the next step S22, ISO9660 information is read. The head address of each file is stored, and the fixed size of each file is obtained from the file size of the ISO9660 information.
[0043]
In step S23, the attached information of each file, for example, the information of the Exif tag is read, and the presence or absence of an unphotographed mark in each image area is confirmed. The unphotographed image area is an empty area where a dummy file is recorded. In step S24, the number of unphotographed marks is set to the number of remaining photographable images, and the initialization processing ends. In addition, in step S23, when the shooting marks are added to all the image areas, the display of the remaining number of shootable images is set to zero. In this case, a warning message indicating that the disk is full or a sound reproduction may be performed.
[0044]
FIG. 8 is a flowchart showing the flow of the photographing operation controlled by the CPU 6. In step S31, it is detected whether or not the shutter button has been pressed. When the depression of the shutter button is detected, the image signal is read from the CCD 1 in step S32.
[0045]
Since the size of the image area is fixed, the compression rate of JPEG is set in step S33 such that the captured image signal falls within the image area. Then, in step S34, JPEG encoding is performed. In step S35, the file size of the encoded data is calculated. In step S36, it is determined whether or not (the size of the captured image file> the fixed size).
[0046]
If the result of the determination in step S36 is affirmative, that is, if it is determined that the size of the image file is too large, the compression ratio of JPEG is increased in step S37. Increasing the compression ratio means reducing the size of the compressed file. Then, JPEG encoding in step S34 is performed. The compression ratio is changed until it is determined that the size of the image file falls within the fixed size. If it is determined in step S36 that the size of the image file is smaller than the fixed size, in step S38, the encoded image data file is overwritten on the file with the unphotographed mark. Writing of the encoded image data is performed in the same manner as the writing method of the dummy file. Then, the unphotographed mark relating to the overwritten dummy file is changed to a photographed mark.
[0047]
As an example, in step S33, a predetermined compression ratio is set assuming an image having a relatively small amount of generated data when encoded by JPEG such as a flat image. In this case, an appropriate compression ratio can be automatically set by analyzing the captured image signal. Then, by steps S36 and S37, the compression ratio is set as high as possible. This is because the image quality of the decoded image is generally better when the compression ratio is lower.
[0048]
In the case of a CD-RW disc, if there is a physical defect on the disc, recording cannot be performed on that part, so that the area containing that part is skipped and writing is performed on the next area.
[0049]
FIG. 9A shows an example in which JPEG encoded data and Exif tag data are recorded in an image area having a size A, and padding is performed with zero data when a vacant portion is created behind the area. On the other hand, FIG. 9B is an example in which JPEG encoded data and Exif tag data are just arranged in an image area having a size A.
[0050]
In one embodiment of the present invention, there are several methods for erasing an image. The first method is to embed an erasure mark in the Exif tag information portion of the corresponding image area. With this method, an image that should have been erased can be viewed on a personal computer. The second method is a method of embedding an unphotographed mark in the Exif tag information portion of the corresponding image area, and writing an invalid image such as black on the entire image data portion. With this method, the erased image is not visible on the personal computer. Note that not all of the image files but an appropriate number of them may be deleted, and the media can be reused by initializing again.
[0051]
The present invention is not limited to the above-described embodiment of the present invention, and various modifications and applications are possible without departing from the gist of the present invention. For example, as a format of image data, a format other than JPEG such as BMP, GIF, TIFF, or PCX is possible. Further, as the configuration of the digital camera, the encoding of the compressed image may be performed by a hardware configuration, and the memory for storing the imaging signal and the memory for storing the compressed image signal may have different configurations. Further, the digital camera may be provided in a portable computer (a so-called notebook computer), a mobile phone, or the like. Further, the disk-shaped recording medium is not limited to a phase-change type disk such as a CD-RW, but may be a magneto-optical recording disk or the like.
[0052]
【The invention's effect】
As is apparent from the above description, according to the present invention, a personal computer can immediately capture an image without performing a finalizing operation after recording image data, which is convenient. In addition, according to the present invention, the capacity is not lost every time the finalization is performed, and is advantageous in terms of capacity. Furthermore, the time required for finalization is not required.
[0053]
Further, according to the present invention, it is possible to capture an image without installing software such as a UDF reader in a personal computer. A personal computer having a general CD-ROM drive can capture an image with almost no operation.
[0054]
According to the present invention, the UDF file format does not need to be implemented when using the CD-RW packet write method. Further, if the image file is overwritten on the dummy file portion by writing in one packet, there is a high possibility that the image file can be read even in a CD-ROM drive manufactured before the packet write method. This is because one file is not divided into two areas sandwiching a link block specific to the packet write method.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining an outline of ISO9660 used in the present invention.
FIG. 2 is a schematic diagram illustrating an example of a configuration of a digital camera according to the present invention.
FIG. 3 is a schematic diagram for explaining a state of a disk at the end of initialization in one embodiment of the present invention.
FIG. 4 is a flowchart showing a flow of an initialization process in one embodiment of the present invention.
FIG. 5 is a schematic diagram illustrating an example of ISO9660 information set at the time of initialization in which an image area is written by a packet write method according to an embodiment of the present invention.
FIG. 6 is a schematic diagram showing an example of ISO9660 information set at the time of initialization in which an image area is written by a track-at-once method in one embodiment of the present invention.
FIG. 7 is a flowchart showing a flow of a disk information initialization process of the digital camera in one embodiment of the present invention.
FIG. 8 is a flowchart showing a flow of a photographing operation of the digital camera in one embodiment of the present invention.
FIG. 9 is a schematic diagram showing a state in which image data is written in an image area in one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... CCD, 6 ... CPU, 11 ... Drive controller, 12 ... CD-RW disc

Claims (12)

In a data recording device using a rewritable disc-shaped recording medium,
Record management information that defines a predetermined fixed directory structure and file size,
Recording a plurality of dummy files having a file size and a directory structure defined by the management information,
Record lead-in and lead-out for the management information and the dummy file,
A data recording device in which a recording image file is overwritten on the dummy file. In claim 1,
A data recording device for recording information for discriminating between recorded and unrecorded in the dummy file. In claim 1,
A data recording apparatus, wherein the recording image file is compressed image data, and has a means for adjusting a compression ratio so that when the compressed image data is overwritten, the compression ratio is smaller than the data size of the dummy file. In claim 1,
A data recording device in which the disc-shaped recording medium is a CD-RW. In a data recording method using a rewritable disc-shaped recording medium,
Recording management information defining a predetermined fixed directory structure and file size;
Recording a plurality of dummy files having a file size and a directory structure defined by the management information,
Recording lead-in and lead-out with respect to the management information and the dummy file;
Overwriting the dummy file with a recording image file. In claim 5,
A data recording method characterized by recording information for discriminating between recorded and unrecorded in the dummy file. In claim 5,
The recording image file is a compressed image data, and a data recording method for adjusting a compression ratio such that when the compressed image data is overwritten, the compression ratio is smaller than the data size of the dummy file. In claim 5,
A data recording method in which the disc-shaped recording medium is a CD-RW. In a digital camera configured to record captured image data on a rewritable disc-shaped recording medium,
An image sensor, a signal processing unit for processing an image signal generated by the image sensor, a buffer memory for storing an image signal from the signal processor, and recording of captured image data on an initialized disc-shaped recording medium Recording means, and a control device,
The initialization process described above
Record management information that defines a predetermined fixed directory structure and file size,
Recording a plurality of dummy files having a file size and a directory structure defined by the management information,
Recording lead-in and lead-out with respect to the management information and the dummy file,
A digital camera in which a captured image file is overwritten on the dummy file. In claim 9,
A digital camera characterized in that information for discriminating between recorded and unrecorded is recorded in the dummy file. In claim 9,
A digital camera, wherein the captured image file is compressed image data, and has means for adjusting a compression ratio so that when the compressed image data is overwritten, the compression ratio is smaller than the data size of the dummy file. In claim 9,
A digital camera whose disk-shaped recording medium is a CD-RW.

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