JP2007234124A - Content data recorder, content data recording method, and program for recording content data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently record a plurality of content data onto a disk recording medium. <P>SOLUTION: The content data recorder is equipped with: a communication module generating means (34) for forming communication modules 33-1 to 33-n in association with received n pieces of content data and dividing each of content data into prescribed block data to successively store these block data, data size and received time; and a data re-constructing means (36) for recording the content data onto the disk recording medium in such a manner that: the block data are successively acquired from the communication modules 33-1 to 33-n for each unit time T of file preservation and stored in a content data table; the receiving time related with the block data, relative address of the block data in the content table, and an information identifier of content corresponding to the data size are related to each other and stored in a retrieval information table; and a table size of the retrieval information table, the retrieval information table and content table are stored in one table file. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a content data recording device, a content data recording method, and a content data recording program, and in particular, records at least one content data of a monitoring video and a sound collected near a monitoring location on a disk recording medium. The present invention relates to a content data recording apparatus, a content data recording method, and a content data recording program that can be applied to a monitoring system or the like.

In a recording method in a video browsing system that stores and reproduces image data (which may include audio data) acquired from a plurality of Web cameras in synchronization, a disk recording device is fixed to each Web camera. There is known a method of securing a circular recording area in advance and recording image data together with time information (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2005-210434

  In a video surveillance system that records video data supplied from each of a plurality of surveillance cameras on a disk recording device, a JPEG system capable of efficient data communication and data recording in relation to the amount of image data and image quality, In many cases, an encoding system such as the MPEG system is used. When the motion JPEG method is applied as data compression processing of video data in the video surveillance system, a large difference is produced in the amount of compressed image data per frame depending on the image size, compression rate, frame rate, and the like. Also, in data compression processing, the amount of compressed image data varies depending on the complexity of the image. Therefore, particularly in the video surveillance field, the difference in the imaging target (monitoring location) of the surveillance camera, daytime and nighttime even at the same location. There is a large difference in the amount of compressed image data due to the difference in the imaging time zone.

  Furthermore, in a recording apparatus, for example, compressed image data and uncompressed image data are generally recorded using a detection signal from a door opening / closing sensor as a recording start trigger. This greatly depends on the installation status of the sensor. Furthermore, when the target of monitoring is not the captured video but the collected audio, the amount of audio data per unit time (when compressed, the amount of compressed audio data) is assumed to be much smaller than the amount of video data. Is done. From the above, the amount of compressed image data and compressed audio data per unit time supplied to the recording device from each of a plurality of surveillance cameras usually differs depending on the surveillance camera, the time zone, and the monitoring target. is there.

  When the recording method of allocating a fixed circular recording area for each surveillance camera and recording image data according to the conventional method described above is adopted in the video surveillance system, the period for which the image data is desired to be retained (for example, one month) It is necessary to allocate a data recording area in advance. In this case, when determining the size of the data recording area, various conditions such as the installation location of the surveillance camera, the operation time zone, the data type, etc. must be taken into account due to the circumstances as described above, and the system setting is difficult. There is a complicated problem. Further, since it is necessary to increase the number of fixed circulating recording areas as the number of surveillance cameras increases, there is a problem in the flexibility of the system. Furthermore, when all the image data recorded in a specific time zone is to be taken out, a problem arises in that convenience is impaired because a complicated operation such as cutting out the portion of the specific time zone and saving only that portion separately is required. There is.

  Furthermore, when data is recorded using a hard disk as a recording medium, a seek time is required for the write header to move on the disk surface. When the writing operation is performed, the number of times of writing to the hard disk increases with an increase in the number of surveillance cameras, so that the total seek time also increases with the number of surveillance cameras. As a result, there is a problem that the recording capacity per unit time is limited.

  Therefore, the present invention has been made in view of the above-described problems, and the object of the present invention is to record content data supplied from a plurality of content data supply sources for each content data supply source when recording the content data on a disk recording medium. Content data recording apparatus and content data recording method that do not require allocation of a fixed circular recording area, facilitate system setting of an apparatus to which the present invention is applied, and exhibit system construction flexibility And a content data recording program.

  The present invention also provides a content data recording apparatus, content data recording, which can efficiently execute a write operation to a disk recording medium by recording a plurality of content data together in a single data file for a predetermined time. It is an object to provide a method and a program for recording content data.

In a content data recording apparatus for receiving a plurality of content data and recording it on a disc recording medium (37),
A plurality of communication modules (33-1 to 33-n) are created corresponding to each of the received plurality of content data, and the corresponding content data is assigned to each of the created plurality of communication modules. Communication module generating means (34) for sequentially storing information in which the block data, the data size thereof and the reception time information are associated with each other.
For each predetermined unit time (TS to TS + T), the stored information is sequentially acquired from each of the plurality of communication modules, and block data of the information is stored in the content data table (62). A search information table (63) that associates reception time information associated with the block data, relative address information of the block data in the content table, a data size of the block data, and an information identifier of content data corresponding to the block data. The data reconstructing means for calculating the data size of the search information table, storing the data size, the search information table, and the content table in one data file and recording them on the disc recording medium ( 36)
A content data recording apparatus (13) configured to record the plurality of content data received for a desired time on the disk recording medium as the plurality of data files for each predetermined unit time
Is to provide.

The invention described in claim 2
In a content data recording method for recording a plurality of received content data on a disk recording medium (37),
A plurality of communication modules (33-1 to 33-n) are created corresponding to each of the plurality of received content data, and the corresponding content data is assigned to each of the created plurality of communication modules. While having a first step of dividing into block data and sequentially storing information in which the block data is associated with the data size and reception time information,
For each predetermined unit time (TS to TS + T), the stored information is sequentially obtained from each of the plurality of communication modules, and block data of the information is stored in the content data table (62). A search information table (63) associating reception time information associated with block data, relative address information of the block data in the content table, a data size of the block data, and an information identifier of content data corresponding to the block data The second step of calculating the data size of the search information table, storing the data size, the search information table, and the content table in one data file and recording them on the disc recording medium (S901- S912)
The content data recording method is characterized in that the plurality of content data received for a desired time are recorded on the disk recording medium as the plurality of data files for each predetermined unit time.

The invention described in claim 3
A content data recording program executed by a computer (13) to record a plurality of received content data on a disk recording medium (37),
A plurality of communication modules (33-1 to 33-n) are created in correspondence with each of the received plurality of content data, and the corresponding content data is assigned to each of the created plurality of communication modules. While having a first step of dividing into block data and sequentially storing information in which the block data is associated with the data size and reception time information,
Every predetermined unit time (TS to TS + T), the stored information is sequentially obtained from each of the plurality of communication modules, and block data of the information is stored in the content data table (62). A search information table (63) associating reception time information associated with block data, relative address information of the block data in the content table, a data size of the block data, and an information identifier of content data corresponding to the block data The second step of calculating the data size of the search information table, storing the data size, the search information table, and the content table in one data file and recording them on the disc recording medium (S901- S912)
The present invention provides a content data recording program for executing the recording of the plurality of content data received for a desired time on the disc recording medium as the plurality of data files for each predetermined unit time.

  According to the present invention, a plurality of received content data are stored in association with a search information table and a content data table in one data file every predetermined unit time, and the data file is recorded on a disk recording medium. Therefore, it is not necessary to divide the data recording area of the disk recording medium prior to recording, and content data can be recorded. Thereby, the system setting of the apparatus can be facilitated and the flexibility of system construction can be exhibited.

  In addition, according to the present invention, even when the number of content data increases, the number of write operations to the disk recording medium does not increase proportionally, so that data recording processing can be performed efficiently, and system expandability is improved. high.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. First, FIG. 1 shows the overall configuration of a monitoring system to which an embodiment of the present invention is applied. In the figure, the monitoring system 1 has a configuration in which each of network cameras 11-1 to 11-6 and a data recording device 13 are connected via a network 14. The microphones 12-1 and 12-2 are connected to the cameras 11-5 and 11-6, respectively.

  In the monitoring system 1 having such a configuration, the data recording device 13 has a function as a controller for controlling the entire monitoring system 1, and controls each of the network cameras 11-1 to 11-6 to control each network. It is possible to cause the camera to capture an image of the monitoring target or to collect sound from each microphone. Each video data captured by the network cameras 11-1 to 11-6 is compressed by the JPEG method inside each network camera, and then transmitted to the data recording device 13 for recording. The audio data collected by the microphones 12-1 and 12-2 is also compressed by the G711 system inside the connected network cameras 11-5 and 11-6, and then transmitted to the data recording device 13. Recorded. Hereinafter, data received and recorded by the data recording device 13 will be referred to as content data.

  Next, each device constituting the monitoring system 1 will be described. FIG. 2 shows a schematic internal configuration of each of the network cameras 11-1 to 11-6 in the present embodiment (hereinafter, each network camera is referred to as the network camera 11 as appropriate). In the figure, a network camera 11 includes an optical system 21 such as an imaging lens, an imaging unit 22 as a photoelectric conversion unit such as a CCD, and an image data processing unit 23 that compresses captured image data using the JPEG method. The microphone input signal from either the microphone 12-1 or 12-2 connected via the microphone input terminal and the line input signal from the external device connected via the line input terminal are selectively input. The audio data processing unit 24 that performs data compression processing by the G711 method, the compressed data supplied from the image data processing unit 23 and the audio data processing unit 24 are converted into IP packets, sent to the network 14, and the data recording device 13 is a network for receiving various control commands transmitted from 13 and outputting them to the control unit 26 described later. An interface unit 25, and a control unit 26 for controlling the respective components of the internal network camera 11.

  Note that the network camera 11 does not necessarily include the audio data processing unit 24, and the audio data processing unit 24 does not necessarily include both the microphone input terminal and the line input terminal. The data compression method for video data and audio data is not limited to the JPEG method or the G711 method, but may be another known data compression method. Furthermore, it is good also as a structure which does not perform a data compression process inside the network camera 11. FIG.

  Next, the data recording device 13 in this embodiment will be described. The data recording device 13 is a device that can be configured by a general computer including a disk recording device such as a hard disk drive and a network interface unit, for example, a personal computer (PC). When the data recording device 13 is constituted by a PC, the data recording device 13 operates a known operating system (OS), and a control program is executed by the CPU under the system control by the OS, and the content data disc Recording to the recording device is executed.

  Next, FIG. 3 shows a schematic functional block of a part related to the content data recording function, which is the main function of the data recording device 13, and will be described. In the figure, the data recording device 13 includes a communication interface unit 31, a camera information storage unit 32, and communication modules 33-1 to 33-n (n is the number of content data generation sources, an integer of 1 or more). A communication module generation unit 34 that creates and manages, a timer unit 35, a data reconstruction unit 36, and a data recording unit 37 are provided as main functions.

  In the above configuration, the communication interface unit 31 receives IP packetized content data transmitted from the network camera 11 according to a communication procedure such as HTTP (Hyper Text Transport Protocol) or RTP (Real-time Transport Protocol). And has a function of extracting the content data from the packet data and supplying the content data to the communication module generation unit 34.

  The camera information storage unit 32 stores address information (for example, IP address) in the network 14 of the network camera 11, the number of acquired images (frame rate) per unit time (for example, 1 second), and an audio bit rate as necessary. Including camera information related to data communication and data recording. Actually, when the control program is activated, a setting file in which camera information is recorded is read into a memory (not shown) and managed.

  The communication module generation unit 34 has a function of creating and managing one or a plurality of communication modules 33-1 to 33-n when the number of content data generation sources is n. That is, the communication module generation unit 34 refers to the camera information in the camera information storage unit 32 and creates the communication modules 33-1 to 33-n for each content data generation source. Specifically, according to the example of FIG. 1 in the present embodiment, n is the total of the number 6 of network cameras 11-1 to 11-6 and the number 2 of microphones 12-1 and 12-2. The communication module generation unit 34 creates the communication modules 33-1 to 33-8 in association with the network cameras 11-1 to 11-6, the microphone 12-1, and the microphone 12-2, respectively.

  Here, FIG. 4 shows a schematic functional configuration block of any one of the communication modules 33-1 to 33-n (hereinafter referred to as the communication module 33 as appropriate). In the figure, the communication module 33 includes a data receiving unit 41, a reception time adding unit 42, and a received data buffer unit 43. The data receiving unit 41 forms content data supplied from the network camera 11 via the communication interface unit 31 as block data corresponding to the data type. That is, for example, when the data type is JPEG, JPEG compressed image data for one frame is regarded as one block data, and when the data type is G711, PCM data for a predetermined packet is regarded as one block data.

  The data receiving unit 41 associates the formed one block data with the data size and supplies the data to the reception time adding unit 42. The reception time adding unit 42 acquires the current time from the time measuring unit 35 and supplies the current time to the reception data buffer 43 unit in association with one block data.

  The reception data buffer unit 43 is a storage area for storing the content data of one block data supplied from the reception time adding unit 42, the data size of the data, and the reception time in association with each other. The input / output order of the reception data buffer unit 43 is a FIFO type. FIG. 5 schematically shows a data configuration example of the reception data buffer unit 43.

  Returning to the description of FIG. 3, the timer unit 35 is a timepiece having a function of acquiring time. The time acquired by the time measuring unit 35 may be hour: minute: second or date / time information including year: month: day. In the present embodiment, the time will be described as hours: minutes: seconds.

  The data recording unit 37 is a recording unit provided with a recording medium such as a hard disk, an optical disk such as a DVD, or a semiconductor memory. In particular, the data recording unit 37 is preferably a recording medium that can be accessed at high speed such as a hard disk and is relatively low cost. In this embodiment, the data recording unit 37 includes a recording unit using a hard disk.

  Next, the data reconstruction unit 36 will be described with reference to the schematic internal configuration block of FIG. In the figure, the data reconstruction unit 36 acquires a set of reception time, content data, and data size from the reception data buffer unit 43 of each of the communication modules 33-1 to 33-n. A search information table 63 is generated. The data reconstruction unit 36 is operated by a data storage control unit 61 that is actually executed as a thread managed in the control program.

  FIG. 9 is a flowchart illustrating an example of the operation of the data storage control unit 61 in this embodiment. When the control program is activated and a thread for executing the processing shown in the figure is started, the current time is acquired from the time measuring unit 35 and set to the content data storage time TS (step S901). Next, a sleep operation of 10 milliseconds is executed (step S902). Here, the sleep operation refers to waiting without executing any processing for 10 msec.

  Next, the current time is acquired again from the time measuring unit 35, the difference from the content data storage time TS is calculated, and the difference value is compared with the file storage unit time T (step S903). The file storage unit time T indicates the range of the reception time of content data recorded in one file, and in this embodiment, 5 seconds is set. That is, for example, when the content data storage time TS is set to 10:10:00, the file storage unit time T is 5 seconds, so the network cameras 11-1 to 11-11 from 10:10:00 to 10:10:05 are used. The content data supplied from -6 is stored in one file.

  In step S903, while the difference between the current time and the content data storage time TS is shorter than the file storage unit time T, the process returns to step S902 to execute the sleep operation again. On the other hand, if it is determined that the difference between the current time and the content data storage time TS is equal to or longer than the file storage unit time T, the process proceeds to data acquisition processing from the communication modules 33-1 to 33-n after step S904. To do.

  Hereinafter, data acquisition processing from the communication modules 33-1 to 33-n after step S904 will be described. First, the communication module index D (D = 1 to n) is initialized to 1 (step S904). Next, all combinations of the reception time, content data, and data size from the content data storage time TS to TS + T are acquired from the communication module 33-D corresponding to the communication module index D (step S905). Next, only content data among the acquired data is recorded in the content data table 62 (step S906).

  Here, FIG. 7 schematically shows a data configuration example of the content data table 62. As shown in the figure, content data is recorded in the content data table 62 in the order of writing.

  Next, an information identifier is generated, and this information identifier, the reception time, the relative address of each content data in the content data table 62, and the data size of each content data are associated and recorded in the search information table 63 ( Step S907). This generated information identifier is unique information for each communication module, and is composed of, for example, information combining the IP address and data type of the corresponding network camera. Specifically, when the IP address of the network camera 11-1 is 123.22.10.1 and the data type is image data according to the JPEG method, the information identifier is “123.22.10.1-JPEG. In addition, when the IP address of the network camera 11-5 is 123.22.10.5 and the data type is voice data according to the G711 system, the information identifier is “123.22.10.5-G711”. And

  Since the information identifier only needs to be unique information for each content data generation source, it may be determined in advance for each content data generation source when the control program is started.

  FIG. 8 schematically shows a data configuration example of the search information table 63. As shown in the figure, the search information table 63 is associated with data of a set of an information identifier, a reception time, a relative address of each content data in the content data table 62, and a data size of each content data. Recorded in writing order.

  Next, the communication module index D is incremented by one (step S908), and the value of D is compared with the total number n of communication modules. If the value of D is equal to or smaller than the total number n, step is performed. The process returns to S905 (step S909). That is, various data in the same time zone are added to the content data table 62 and the search information table 63 for all the communication modules 33-1 to 33-n (steps S905 to S909).

  On the other hand, if the value of D is larger than the total number n, a data file based on the time information is created. Specifically, the data file is opened, and the table size of the search information table 63 is recorded as a header information from the top of the data file, for example, as a fixed-length numeric string of 10 bytes. Then, the data in the search information table 63 is added to the file, the data in the content data table 62 is further added, and the data file is closed (step S910). As a result, a data file from the content data storage time TS to TS + T is generated.

  Next, the contents data table 62 and the search information table 63 are erased to create another data file (step S911), the content data storage time TS is set to TS + T (step S912), and the process returns to step S902.

  FIG. 10 shows a data structure in one data file among the data files created by the processing described above. As shown in the figure, in one data file, the table size of the search information table 63 is first recorded as header information in the 10-byte area from the beginning, then the data of the search information table 63 is recorded, and then Information of the content data table 62 is recorded.

  The data file generated in this way is recorded in the data recording unit 37 as organized content data from all content data generation sources for the file storage unit time T from the content data storage time TS. As a result, if content data is received from, for example, 10:10:00, the data recording unit 37 stores a data file of 10: 10: 00-10: 10: 05, 10: 10: 05-10: 10. : A plurality of data files such as 10 data files are recorded.

  Here, the relationship between the standby time required for the sleep operation and the file storage unit time T will be described. The standby time for the sleep operation needs to be set to a time sufficiently shorter than the file storage unit time T. As the waiting time becomes longer, more buffers are used, and as the waiting time becomes shorter, the processing load increases. Therefore, this waiting time is preferably in the range of 10 ms to 50 ms.

  The file storage unit time T is a time that should be determined in consideration of the trade-off relationship between the performance of the data recording device 13 and the memory. That is, since the number of data files increases as the file storage unit time T becomes shorter, the processing load for reading content data from these data files becomes heavier and performance decreases. On the other hand, the required memory capacity in the data reconstruction unit 36 increases as the file storage unit time T increases.

  An example in which the data recording device 13 is configured by a PC and content data for one hour is stored in the data recording unit 37 using a hard disk will be specifically described. For example, when the folder structure of the data recording unit 37 has a hierarchical structure such as a data storage folder → a date folder → a time folder, and content data for one hour is stored in the time folder, a file storage unit time T is set. Assuming 5 seconds, the number of data files stored in the time folder is 720, and there is no problem in terms of PC performance as long as this number of files is reached. Further, when storing 30 fps video data for 16 channels in a VGA size (640 × 480 pixels) JPEG image (an average of about 41 Kbytes), the memory capacity required for the buffer of the data reconstruction unit 36 is about 100M. It becomes a byte and fits within the practical range. Therefore, the file storage unit time T is preferably in the range of 5 seconds to 10 seconds.

  When the data file recorded in the data recording unit 37 is referred to by reproduction processing as described above, the data file corresponding to the time to be reproduced is selected, and the search information recorded in the 10-byte area from the top of the data file The table size of the table 63 is acquired, and the information identifier to be referred to is searched from the area recorded for the table size from the beginning of the file 10 bytes ahead, and the relative address of the content data at the time to be referred to is acquired. Then, it is possible to specify content data to be referred to based on the address at which the content data table starts recording and using the acquired relative address as an offset.

  As described above in detail, according to the present embodiment, a plurality of content data generation sources, that is, the network cameras 11-1 to 11-6, the microphone 12-1, and the microphone 12-2 are supplied to the data recording device 13. Content data is recorded in a single data file in association with the search information table 63 and the content data table 62 every file storage unit time T, and these data files are recorded in the data recording unit 37. Content data can be recorded without the need to divide the data storage area of the data recording unit 37 prior to recording. Therefore, the system setting of the data recording device 13 can be facilitated and the flexibility of system construction can be exhibited.

  In addition, with the above configuration, the number of seeks for the write operation to the data recording unit 37 does not increase in proportion to the increase in the number of content data generation sources, and thus efficient data recording processing can be performed. A high monitoring system can be constructed.

1 is an overall configuration diagram of a monitoring system to which an embodiment of the present invention is applied. It is a schematic internal block diagram of a network camera in an embodiment of the present invention. FIG. 3 is a schematic functional block diagram of a portion related to a content data recording function which is a main function of the data recording device in the embodiment of the present invention. It is a functional block diagram of the outline of a communication module in the embodiment of the present invention. It is the figure which showed typically the example of a data structure of the reception data buffer part in embodiment of this invention. FIG. 3 is a schematic internal configuration block diagram of a data reconstruction unit in the embodiment of the present invention. It is the figure which showed typically the data structural example of the content data table in embodiment of this invention. It is the figure which showed typically the example of a data structure of the search information table in embodiment of this invention. It is a flowchart for demonstrating the operation example of the data preservation | save control part by the control program in embodiment of this invention. It is the figure which showed the data structure of the data file in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Monitoring system 11-1 to 11-6 Network camera 12-1, 12-2 Microphone 13 Data recording device 14 Network 21 Optical system 22 Imaging part 23 Image data processing part 24 Audio | voice data processing part 25 Network interface part 26 Control part 31 Communication interface unit 32 Camera information storage unit 33-1 to 33-n Communication module 34 Communication module generation unit 35 Timekeeping unit 36 Data reconstruction unit 37 Data recording unit 41 Data reception unit 42 Reception time addition unit 43 Reception data buffer unit 61 Data Storage control unit 62 Content data table 63 Search information table

Claims (3)

In a content data recording apparatus for receiving a plurality of content data and recording it on a disk recording medium,
A plurality of communication modules are created corresponding to each of the received plurality of content data, and the corresponding content data is divided into predetermined block data for each of the created plurality of communication modules. Communication module generation means for sequentially storing block data, information associated with the data size and reception time information;
Every predetermined unit time, the stored information is sequentially obtained from each of the plurality of communication modules, block data of the information is stored in a content data table, and reception associated with the block data is received. The time information, the relative address information of the block data in the content table, the data size of the block data, and the information identifier of the content data corresponding to the block data are stored in the search information table in association with each other, and the data of the search information table Data reconstruction means for calculating the size, storing the data size, the search information table, and the content table in one data file, and recording the data on the disk recording medium;
A content data recording apparatus configured to record the plurality of content data received for a desired time on the disc recording medium as the plurality of data files for each predetermined unit time. In a content data recording method for recording a plurality of received content data on a disk recording medium,
A plurality of communication modules are created corresponding to each of the plurality of received content data, and the corresponding content data is divided into predetermined block data for each of the created plurality of communication modules. While having a first step of sequentially storing information in which data is associated with the data size and reception time information,
Each predetermined unit time, the stored information is sequentially obtained from each of the plurality of communication modules, block data of the information is stored in a content data table, and a reception time associated with the block data Information, the relative address information of the block data in the content table, the data size of the block data, and the information identifier of the content data corresponding to the block data are stored in the search information table, and the data size of the search information table And calculating the data size, storing the search information table and the content table in one data file, and recording the data size on the disk recording medium,
A content data recording method comprising: recording the plurality of content data received for a desired time on the disc recording medium as the plurality of data files for each predetermined unit time. A content data recording program executed by a computer to record a plurality of received content data on a disk recording medium,
A plurality of communication modules are created corresponding to each of the plurality of received content data, and the corresponding content data is divided into predetermined block data for each of the created plurality of communication modules. While having a first step of sequentially storing information in which data is associated with the data size and reception time information,
Each predetermined unit time, the stored information is sequentially obtained from each of the plurality of communication modules, block data of the information is stored in a content data table, and a reception time associated with the block data Information, the relative address information of the block data in the content table, the data size of the block data, and the information identifier of the content data corresponding to the block data are stored in the search information table, and the data size of the search information table And calculating the data size, storing the search information table and the content table in one data file, and recording the data size on the disk recording medium,
A program for recording content data, which is executed to record the plurality of content data received for a desired time on the disk recording medium as the plurality of data files for each predetermined unit time.

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