JP2009271635A - File editing apparatus and file editing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To edit a file stored in a recording medium having a recording/reproducing format with the amount of record data from the beginning of a file to a starting point of data fixed therefor. <P>SOLUTION: An operation unit 15 designates a division point as a location of division of a first file. A microprocessor 14 functioning as a control unit identifies a modified division point as a reference when dividing actually. Further, the microprocessor 14 updates clustering information of a FAT so as to form a portion from a first header as a header of the first file to the modified division point as a second file. Further, the microprocessor 14 produces a second header for identifying the second file. A memory 16 stores the second file. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a file editing apparatus and a file editing method for editing a file stored in a recording medium.

  In recent years, small recording / reproducing apparatuses using individual recording elements such as flash memories as recording media have been widely used. In such a recording / reproducing apparatus, it is desired to record audio information (audio signal) or video information (video signal) over a certain period of time, and then to edit the file for file management. .

  For example, there has been proposed a technique for editing a data stream or an MPPEG audio (MPEG Audio) format file compressed using the MPEG (MPEG) format (see, for example, Patent Document 1 and Patent Document 2). In this technique, a file is divided by dividing at a cluster break, which is the minimum unit of information handled in editing processing, and padding an empty portion of the cluster.

The above-described editing technique is possible when employing an MPEG format or the like that is scheduled to be padded with an empty portion of the cluster. Another example of such a format is the RIFF waveform audio format (see Non-Patent Document 1 and Non-Patent Document 2). FIG. 13 is a diagram schematically showing the RIFF waveform Audio Format (hereinafter abbreviated as RIFF Wave file format). The RIFF Wave file format is a format in which the length from the beginning of the file to the start point of the data can be arbitrarily adjusted by inserting a junk chunk (portion surrounded by a broken line in FIG. 13). In this way, junk chunks are used to divide files at arbitrary data stream positions. In recent years, not only the above-mentioned MPEG format and RIFF Wave file format but also the DSF (DSF) file format has been widely used as a file format (see Non-Patent Document 3). The DSF file format is a format (extension “.dsf”) for Direct Stream Digital (DSD) data developed by the applicant described in the application of the present application and widely published. FIG. 14 is a schematic diagram showing a DSF file format. As shown in FIG. 14, in the DSF file format, the data from the beginning of the file to the start point of the data is always fixed to 92 bytes (Byte), and the DSD chunk and the fmt chunk must exist.
Japanese Patent Laid-Open No. 11-176083 JP 2000-298611 A `` Multimedia Programming Interface and Data Specification V1.0 '' (Microsoft and IBM) `` Multimedia Data Standards Update / April 15,1994 '' (Microsoft and IBM) "DSF File Format Specification Version 1.01" (Sony) Format Acquisition Registration URL http://www.dsd-format.sony.net/en/index.php

  As described above, in the MPEG format and the RIFF Wave file format, a file can be easily divided by inserting (padding) junk chunks. On the other hand, when the DSF file format is used, file division is not easy. FIG. 1 schematically shows a case where a file based on the DSF file format is divided in the same manner as the MPPEG format and the RIFF Wave file format. FIG. 1A shows a file F1 before division, and a division point DP indicated by an arrow indicates a position of a data stream desired to be divided. FIG. 1 (B) shows one divided file F1-1 after division, and FIG. 1 (C) shows the other divided file F1-2 after division. Here, cluster CL (X) indicates a cluster number, and X is an integer. Here, the cluster is the minimum unit of information handled in the editing process, and is the minimum unit of a plurality of data chunks. Further, the data referred to here is data having a predetermined length by arranging bits from upper to lower.

  In the divided file F1-1 shown in FIG. 1B, the cluster CL (2), the cluster CL (3), the cluster CL (4), and the cluster CL (A) including the division point DP are continued. Here, the cluster CL (A) includes the recorded contents up to the dividing point DP of the cluster CL (5). The frame size recorded in the header (HEADER) of the cluster CL (2) is used by changing the file size information recorded in the header of the file F1 according to the storage capacity up to the division point DP.

  In the divided file F1-2 shown in FIG. 1C, the cluster CL (2) before the division including the header is copied and used as the cluster CL (B), and the cluster CL (5), cluster CL (6), cluster It continues with CL (7), cluster CL (8), and cluster CL (9). Here, the portion from the rear of the header of the cluster CL (B) to the dividing point DP of the cluster CL (5) (the portion described as SPACE) is invalid data. In the DSF format, the data from the beginning of the file to the start point of the data is always fixed at 92 bytes (Byte), and invalid data cannot be included. For this reason, even if such division is performed, data that should not originally be included in the divided file F1-2 enters the beginning of the file, so that abnormal noise is generated at that portion. In this sense, it cannot be said that the file is correctly divided.

  In view of the above-described problems, the present invention provides a file editing apparatus capable of editing a file stored in a recording medium having a recording / playback format in which the amount of recording data from the beginning of the file to the start point of the data is fixed. I will provide a. It also provides a file editing method.

  The file editing apparatus of the present invention designates a division point that is a division position of a first file that is formed by combining a plurality of clusters each having a first header at the head and a plurality of data. And a clustering of fat so as to identify a correction division point located at a predetermined distance from the head of the cluster including the division point, and form the first header to the correction division point as a second file. A control unit that updates information and generates a second header for specifying the second file, and a memory that stores the second file are provided.

  Another file editing apparatus according to the present invention has a first header at a head portion, and a division point that is a division position of a first file formed by combining a plurality of clusters composed of a plurality of data. An operation unit for designating a correction division point located at a predetermined distance from the head of the cluster including the division point, and forming a third header at the head of the cluster including the division point, A control unit that adds a third file formed including a header to the fat directory entry information; and a memory that stores the third file.

  According to the file editing method of the present invention, the operation unit has a first header at the head and is a division position of the first file formed by combining a plurality of clusters composed of a plurality of data. The division point is designated, and the control unit specifies a correction division point located at a predetermined separation position from the head of the cluster including the division point, and forms the first division to the correction division point as a second file. Thus, the fat clustering information is updated, a second header for specifying the second file is generated, and the memory stores the second file.

  In the file editing apparatus and editing method of the present invention, the operation unit designates a dividing point that is a position for dividing the first file. The control unit specifies a correction division point, updates the clustering information of the fat so as to form the second file from the first header to the correction division point, and specifies a second file. Generate a header. A memory stores the second file. Therefore, the file that divides the first file to form the second file can be edited.

  In another file editing apparatus according to the present invention, the operation unit designates a division point that is a division position of the first file. The control unit specifies the correction division point, forms a third header at the head of the cluster including the division point, and adds the third file to the fat directory entry information. A memory stores the third file. Therefore, the file that divides the first file to form the third file can be edited.

  According to the present invention, with respect to a file stored in a recording medium having a recording / reproducing format in which the amount of recording data from the beginning of the file to the start point of the data is fixed by dividing the file on the basis of the corrected dividing point. Can provide editing technology.

  FIG. 2 shows an editing apparatus according to the embodiment. The editing apparatus 10 can also be regarded as a recording / reproducing apparatus having an editing function as one of the functions of a recording / reproducing apparatus for recording / reproducing information on a recording medium. In the editing apparatus 10, only the main part is described. In the editing apparatus, the portion relating to the playback function may or may not be provided, and therefore this portion is not described in the editing apparatus 10.

  The editing apparatus 10 includes an acoustic signal recording unit having a function of recording acoustic signals such as music, conversations, and lectures. The acoustic signal recording unit includes a microphone 11 that converts an acoustic signal into an electrical signal. In addition, a microphone amplifier 12 that amplifies the electric signal obtained by the microphone 11 is provided. In addition, an A / D converter 13 that converts an analog signal from the microphone amplifier 12 into a digital signal is provided. Further, a microprocessor 14 for processing a digital signal obtained by the A / D converter 13 is provided. An operation unit 15 that functions as an interface between the microprocessor 14 and the operator is provided. Further, a memory 16 is provided as a storage medium for storing the acoustic signal processed by the microprocessor 14. The microprocessor 14 includes a central processing unit (CPU) 141, a ROM (ROM) 142, and a RAM (RAM) 143. The CPU 141, the ROM 142, the RAM 143, and the memory 16 are connected to each other via a bus line.

  The editing apparatus 10 has a function as a so-called icy (IC) memory that stores and reproduces meeting contents and meeting contents, for example. In such an IC memory, a flash memory is used as the memory 16, and the content of a long-time meeting can be continuously stored while the size of the apparatus is small. Further, since the flash memory is a non-volatile memory, the memory is maintained even after the power supply from the power source is cut off.

  An example of how the editing apparatus 10 is used will be described below. There are cases where the contents of long-time meetings are continuously stored and then the contents are organized. In other words, editing may be necessary. Specifically, the contents of the conference are recorded continuously without any identification information, and then the specific speakers in the conference are classified afterwards to make the content of the speech belonging to the speaker. It may be possible to facilitate the search by attaching identification information. In addition, it may be necessary to record the contents of the conference continuously without adding identification information and then classify the information by adding identification information for each agenda of the conference. In such a case, whether the editing can be easily performed or the editing is difficult causes a difference in the convenience of using the apparatus.

  As another example of the use of the editing apparatus 10, when a plurality of music pieces are continuously played at a concert or the like, they are continuously recorded as one file and edited afterwards. An example is given. In such editing, a new file is divided for each song or for each album in which a plurality of songs are selected and combined. Even in such a case, if the editing cannot be performed easily, the convenience of using the apparatus is significantly impaired.

  The editing apparatus 10 according to the embodiment is configured to have a recording function as well as an editing function. The editing apparatus 10 according to the embodiment has a recording function. However, the editing apparatus 10 according to the embodiment can be configured as an editing apparatus that does not have a recording function and exclusively has an editing function. .

  The operation of each part of the editing apparatus 10 will be briefly described. The digital signal obtained through the microphone 11, the microphone amplifier 12, and the A / D converter 13 is subjected to information compression in the microprocessor 14, and the file is stored in the memory 16 as a file according to the DSF file format. The ROM 142 stores processing procedures (programs) in the CPU 141, and the CPU 141 performs recording and editing processes while temporarily storing information in the RAM 143 based on the programs. When the editing apparatus 10 has a playback function, the microprocessor 14 also performs playback processing. Here, the microprocessor 14 functions as a control unit. As long as it functions as a control unit, not only the microprocessor 14 but also a hardware digital circuit can be used instead of the microprocessor 14.

  Regarding the editing technique of the embodiment, prior to specific description with reference to the drawings, the main part of the file editing technique of the embodiment will be summarized below.

  In the file editing technique of the embodiment, the operation unit 15 designates a division point that is a position for dividing the first file. The microprocessor 14 functioning as a control unit specifies a correction division point that is a reference for actual division. Further, the microprocessor 14 updates the clustering information of the fat so as to form the first file, which is the header of the first file, to the corrected division point as the second file. Further, the microprocessor 14 generates a second header for specifying the second file. A memory 16 stores the second file.

  In another file editing technique according to the embodiment, the operation unit 15 designates a division point that is a division position of the first file. The microprocessor 14 specifies a correction division point that is a reference for actual division. Further, the microprocessor 14 forms a third header at the head of the cluster including the division point, and adds the third file to the fat directory entry information. The memory 16 stores the third file.

  3, 4, and 5 are diagrams schematically showing the contents of editing processing performed in the microprocessor 14. The editing process of the embodiment, that is, the process of dividing the file recorded in the DSF file format will be specifically described with reference to each of FIGS.

  FIG. 3 is a diagram showing the configuration of the file F1 before division. In order to simplify the explanation, it is assumed that this file is formed of clusters from cluster CL (2) to cluster CL (9). The numbers in parentheses are cluster numbers. The position of the broken-line arrow is the position of the division point DP for which division is desired. The position of the division point DP is specified by pressing a button arranged on the operation unit 15 (see FIG. 2). In the editing apparatus 10, when the operator recognizes the acoustic information of the part to be divided while reproducing the recorded acoustic information, the position of the dividing point DP is designated by pressing the button.

FIG. 4 is a diagram showing the configuration of the divided file F1-1 after division. Here, the position which is actually divided is changed to modify the division point DP _R indicated by an arrow of a solid line rather than division point DP. This change is a process performed by the CPU 141 of the microprocessor 14 (see FIG. 2). The division point DP is an arbitrary position from the head position of CL (5), and in FIG. 4, is a position farther than 92 bytes from the head position of the cluster CL (5). On the other hand, fix the dividing point DP _R is a position away exactly 92 bytes from the head position of the cluster CL (5). That is, modifications dividing point DP _R is the cluster of the file that was playing at the time the button arranged on the operation unit 15 is pressed (in this case, precisely from the beginning of the cluster CL (5) of the file F1 is changed to 92 bytes in position. Further, if the division point DP is within 92 bytes from the head position of the cluster CL (5) is also modified division point DP _R is exactly from the beginning of the cluster CL (5) 92 Changed to byte position.

As shown in FIG. 4, the files included in the divided file F1-1 after the division are as follows. First, the file from the cluster CL (2) is than clusters modifications dividing point DP _R files F1 belongs before the cluster to the cluster CL (4) is included in the divided file F1-1 after division. In addition, cluster CL (A), which is a cluster copied from cluster CL (5), is included in the divided file F1-1 after division. Then, the FAT clustering information is updated so that the cluster CL (4) and the cluster CL (A) are connected. The update of FAT and FAT clustering information will be described later. In addition, information indicating the file size included in the header of the divided file F1-1 is rewritten. In this case, the file size is the first 92 bytes from the cluster CL (2) to the cluster CL (A) (the number of bytes corresponding to the position occupied by the header). In this way, the number written in the file F1 is updated to generate a new header. That is, the data stored in the hatched area of the cluster CL (A) shown in FIG. 4 is not included in the file size.

  FIG. 5 is a diagram showing the configuration of the divided file F1-2 after division. As shown in FIG. 5, the files included in the divided file F1-2 after the division are as follows. The head of the divided file F1-2 after the division is the cluster CL (5). Then, a new header is generated by overwriting the header for the divided file F1-2 from the top of the cluster CL (5). Then, the divided file F1-2 is added to the FAT directory entry information. Through the above processing, the file F1 is divided into the divided file F1-1 and the divided file F1-2. In each file, the portion described as DATA is usable data. Since each of the divided file F1-1 and the divided file F1-2 conforms to the DSF format, no problem occurs when performing processing such as reproduction.

  FIG. 6 is a diagram showing the concept of fat (FAT). FAT (File Allocation Table) is a management area in the file system. In a FAT file system that is a file system using FAT, a cluster is assigned as a logical unit and a cluster is allocated according to the data size to form a file. At this time, information such as which cluster forms a certain file is recorded in the FAT to manage the file.

  In the example of the FAT shown in FIG. 6, the file MAIN.C is formed of a cluster CL (002), a cluster CL (003), and a cluster CL (006). Information is reproduced in the order of clusters corresponding to the numbers recorded in the FAT. The information content of the cluster CL (002) is data 1 of MAIN.C. The information content of the cluster CL (003) is data 2 of MAIN.C. The content of the information of cluster CL (006) is data 3 of MAIN.C. The file FUNC.C is formed of a cluster CL (004) and a cluster CL (005). The information content of the cluster CL (004) is data 1 of FUNC.C. The information content of the cluster CL (005) is data 2 of FUNC.C. The cluster CL (007) and the cluster CL (008) are unused. As a directory (FAT directory entry), MAIN.C is recorded in the cluster CL (002), and FUNC.C is recorded in the cluster CL (004).

  FIG. 7 is a diagram showing a FAT corresponding to the file F1 shown in FIG. The numbers in parentheses () correspond to the cluster numbers shown in FIG. That is, after the cluster CL (002), the cluster CL (003) is reproduced. Further, after the cluster CL (003), the cluster CL (004) is reproduced. The same applies to other cases.

  FIG. 8 is a diagram showing a FAT corresponding to the divided file F1-1 shown in FIG. That is, after the cluster CL (002), the cluster CL (003) is reproduced. Further, after the cluster CL (003), the cluster CL (004) is reproduced. Then, after the cluster CL (004), not the cluster CL (005) but the cluster CL (00A) is reproduced. Here, since only the file before the division is managed in the directory entry before the division, a new entry is added after the division, and is changed so as to indicate the first cluster of each file. That is, the directory entry before the division is FILE.DSF 002, but the directory entry after the division is rewritten as FILE-1.DSF 002 and FILE-2.DSF 005.

  FIG. 9 is a flowchart showing the above-described editing process, that is, a file dividing process. This will be described below along the flowchart shown in FIG.

In step ST100, the microprocessor 14 receives an instruction from the operation unit 15 and starts a file division process.
In step ST101, the microprocessor 14 designates (sets) a division processing file that is a file to be divided.
In step ST102, the microprocessor 14 specifies (sets) a corrected division point from the division point corresponding to the time point when the instruction from the operation unit 15 is received. In other words, the position of the correction division point is determined to be a position behind the head of the designated cluster by the HEADER size (in this case, 92 bytes).
In step ST103, the microprocessor 14 copies a cluster including the dividing point (this cluster is a cluster including the corrected dividing point as well).
In step ST104, the microprocessor 14 changes the FAT clustering information.
In step ST105, the microprocessor 14 changes the FAT directory entry.
In step ST106, the microprocessor 14 updates the data frame size in the HEADER recorded at the head of the file.
With the above process, the process of dividing the new file (first divided file) formed by the cluster positioned before the corrected dividing point is completed. The new file (first divided file) is stored in the memory 16.

In step ST107, the newly updated HEADER is overwritten at the head of the cluster including the corrected division point (the cluster designated as the division position).
With the above process, the process of dividing a new file (second divided file) formed by the cluster located behind the corrected dividing point is completed. The new file (second divided file) is stored in the memory 16.

As described above, editing including fill division can be freely performed by the technique of the embodiment. However, division must be performed at a position that is a predetermined position away from the beginning of the cluster as a correction division point. In this case, the operation unit 15 instead of the division point DP request to split, to study whether the inconvenience caused to split a modified dividing point DP _R occurs.

  Table 1 summarizes how the time of one cluster changes for each value of the bit rate and cluster size of DSD (Direct Stream Digital) data.

  As can be seen from Table 1, for example, in the case of 2 channels and a bit rate of 2.8 MHz, the time for one cluster is 11.7 msec (milliseconds) when the cluster size is 8 Kbytes. When the cluster size is 16KByte, it is 23.4msec. When the cluster size is 32KByte, it is 46.8msec. Further, for example, in the case of 4 channels and a bit rate of 5.6 MHz, it is 5.9 msec when the cluster size is 8 KByte, 11.7 msec when the cluster size is 16 KByte, and 23.4 msec when the cluster size is 32 KByte.

  Thus, the time corresponding to one cluster is shorter than the time that can be recognized by human hearing and vision. Even if the position of the division point is fixed to the correction division point, the time error between the desired division point and the correction division point that is actually obtained division point remains within the range of 46.8 msec at the maximum. There is no inconvenience caused by the divided processing.

Here, a file editing technique that does not use the technique described in the above-described embodiment will be additionally described. Format the amount of recording data from the beginning of the file to the start of the data is fixed, for example, DSF, even without using the correction dividing point DP _R, as the division position dividing point DP of divided request is issued Splitting is not technically impossible. However, in this case, all the information contained in the file must be extracted and all the files must be reconstructed in order from the beginning of the time series information. That is, all information belonging to the same file other than the information that is required to be edited becomes the object of editing, and the amount of work becomes enormous and the work time becomes long. In addition, the work environment, for example, the processing capacity of the control unit is required to be strengthened, and the recording capacity of the memory is further increased, and the cost of the editing apparatus becomes expensive.

  According to the above-described embodiment, editing can be efficiently performed by dividing the correction division point as a reference. That is, the technique of the embodiment not only enables editing but also makes the editing process more efficient. For example, data movement, duplication, rewriting, etc. required for file editing in the recording medium can be minimized. Further, the processing time for editing and the power consumption of the editing apparatus can be made extremely small. And since it has such a feature, it is possible to achieve downsizing of the editing apparatus. By combining such an editing apparatus and a recording / reproducing apparatus, a portable small-sized editing apparatus (both recording / reproducing apparatus) can be achieved. It can be realized).

  10, FIG. 11 and FIG. 12 are diagrams showing modifications of the above-described embodiment. This will be described. 10 to 12 illustrate a division procedure different from that of the above-described embodiment with reference to the drawings. FIG. 11 shows the divided file F1-2 and FIG. 12 shows the divided file F1-1. The final two divided files are not different from those obtained by the technique of the embodiment described above. The division process is different.

A file F1 illustrated in FIG. 10 is a diagram illustrating an example of a file in a case where the data recorded in the file is audio data in which 2-channel acoustic information is recorded. The R channel (right channel) and the L channel (left channel) are alternately recorded with a predetermined capacity from the beginning of the file. A plurality of R channels and L channels form one cluster. The position of the division point indicated by the operation unit 15 when the button of the operation unit 15 (see FIG. 2) is pressed is the division point DP. Fixed dividing point DP _R are those specified by the microprocessor 14 as a control unit, as described above, a cluster corresponding to the division point beginning from a predetermined of (the division point, modification division point clusters belonging) This is the position of the data that is separated (for example, between 92 bytes).

FIG. 11 is a diagram schematically showing how the divided file F1-2, which is a divided file, is formed. The division is performed in the following procedure. First, copy the cluster CL (3) is a cluster that contains modified dividing point DP _R. Next, the cluster CL (4) is connected to the cluster CL (3). Generate (overwrite) the header of split file F1-2 at the beginning of cluster CL (3).

FIG. 12 is a diagram schematically showing how the divided file F1-1, which is a divided file, is formed. The division is performed in the following procedure. First, split at the position of the corrected dividing point DP _R which is a cluster that contains modified dividing point DP _R cluster CL (3). Then, by rewriting the file size of the header file size corresponding to the head position of the data to the position of the correction dividing point DP _R, it generates a header of the divided file F1-1. The fat (FAT) process is the same as in the above-described embodiment.

  In the description of the above-described embodiment, it has been described that the recorded data is acoustic information. However, the technology of the above-described embodiment may be applied to video information (still image information, moving image information) instead of acoustic information. Needless to say, is applicable.

FIG. 1 is a diagram schematically showing a case where a DSF file is divided in the same manner as the MPPEG format and the RIFF Wave file format. It is a figure which shows the editing apparatus of embodiment. It is a figure which shows the structure of the file F1 before dividing | segmenting. It is a figure which shows the structure of the division | segmentation file F1-1 after division | segmentation. It is a figure which shows the structure of the division | segmentation file F1-2 after division | segmentation. It is a figure which shows the concept of fat (FAT). It is a figure which shows FAT corresponding to the file F1. It is a figure which shows FAT corresponding to the division | segmentation file F1-1. It is a flowchart which shows the process of a file division. It is a figure which shows a file in case the data currently recorded on the file are the audio data by which the acoustic information of 2 channels is recorded. It is a figure which shows typically how the division | segmentation file F1-2 is formed. It is a figure which shows typically how the division | segmentation file F1-1 is formed. It is a figure which shows a RIFF Wave file format typically. It is a schematic diagram which shows a DSF file format.

Explanation of symbols

  10 editing device, 11 microphone, 12 microphone amplifier, 13 A / D converter, 14 microprocessor, 15 operation unit, 16 memory, F1 file (first file), F1-1 split file (second file), F1 -2 Split file (third file)

Claims (5)

An operation unit for designating a division point which is a division position of the first file formed by combining a plurality of clusters each having a first header at the top portion and a plurality of data;
Identifying a correction division point at a predetermined separation position from the head of the cluster including the division point, and updating the fat clustering information so as to form the first file from the first header to the correction division point as a second file; A control unit for generating a second header for specifying the second file;
And a memory for storing the second file. An operation unit for designating a division point which is a division position of the first file formed by combining a plurality of clusters each having a first header at the top portion and a plurality of data;
A correction division point located at a predetermined separation position from the head of the cluster including the division point is specified, a third header is formed at the head of the cluster including the division point, and the third header is included. A controller for adding a third file to the fat directory entry information;
And a memory for storing the third file. The file editing apparatus according to claim 1, wherein the control unit changes the file size information included in the first header to form the second header. The operation unit
Specify the division point that is the division position of the first file formed by combining a plurality of clusters each having a first header at the top and a plurality of data,
The control unit
Identifying a correction division point at a predetermined separation position from the head of the cluster including the division point, and updating the fat clustering information so as to form the first file from the first header to the correction division point as a second file; Generating a second header for identifying the second file;
Memory
A file editing method for storing the second file. further,
The control unit is
A correction division point located at a predetermined separation position from the head of the cluster including the division point is specified, a third header is formed at the head of the cluster including the division point, and the third header is included. Add the third file to the fat directory entry information,
The memory is
The file editing method according to claim 4, wherein the third file is stored.

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