JP2010152425A - File transmission device and file reception device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a file transmission device allowing download service via a one-way communication line, and allowing complementing of a lost portion of a content even in a complementing server with a simple configuration. <P>SOLUTION: The file transmission device 1 for transmitting a file via the one-way communication line M includes: a containerization means 11 for containerizing the content and connection control information indicating a connection condition under which a file reception device can be connected to the complementing server; a blocking means 13 for generating a file wherein the content and the connection control information containerized by the containerization means 11 are blocked with preset size; and a file transmission means 15 for transmitting the file generated by the blocking means 13 to the file reception device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a download system that transmits a file via a unidirectional communication line that is digital broadcasting or multicast communication, and transmits and complements a block corresponding to a missing portion that could not be received via a bidirectional communication line. The present invention relates to a file transmission device and file reception.

Conventionally, various techniques for downloading contents such as software, video, music, etc. via a bidirectional communication line such as an IP network have been proposed (see, for example, Patent Document 1).
In recent years, with the expansion of digital broadcasting and the like, content download services are expected through unidirectional communication lines such as BS digital broadcasting and mobile broadcasting.
JP 2007-212234 A

  Normally, it is assumed that a data error or data loss occurs on a transmission line in a two-way communication line, and even if these occur, a method for retransmitting data has been established, and the user cannot complete content. Can be downloaded in any form.

  However, in a unidirectional communication line such as a broadcast wave, it is not assumed that data with a data error or data loss is retransmitted, and the content is provided to the user while the data error or data loss is included. There is a possibility that. For this reason, when providing a download service via a unidirectional communication line, there is a strong demand for realizing a method for complementing content including data errors and data loss. In view of this, it is conceivable that the user supplements only the portion where the data error or data loss has occurred from the server storing the content via the network.

Hereinafter, problems in the case of providing a download service by BS digital broadcasting or mobile broadcasting will be described.
First, when providing a download service by BS digital broadcasting, data errors and data loss occur in a large number of receiving devices installed over a wide range due to rain attenuation. In this case, it is considered that access (traffic) concentrates in a short time from a large number of receiving apparatuses to the server in order to compensate for data errors and data loss.

  Also, when providing a download service via mobile broadcasting, mobile reception is mainly used. Therefore, depending on the lifestyle of the user, the reception situation, that is, the situation in which data error or data loss occurs differs. Become. For example, during the daytime, the user often moves between buildings and places where the reception situation of the underground shopping street is poor, and it is considered that data errors and data loss are more likely to occur during the day than at night.

  In this way, a large-scale server that can withstand a large amount of access is introduced and operated only to cope with data errors and data loss that are affected by uncertain conditions such as rain attenuation and user movement. That is not realistic.

  Therefore, the present invention provides a file transmission device and a file reception device that enable a download service via a unidirectional communication line and can complement a missing portion of content even with a supplement server with a simple configuration. For the purpose.

  In order to solve the above-described problem, a file transmission device according to claim 1 includes a file transmission device that transmits a file via a unidirectional communication line that is digital broadcasting or multicast communication, and at least one file reception that receives the file. And a complement server that blocks and stores the content contained in the file and transmits a block corresponding to the missing portion of the content that the file receiving device could not receive to the file receiving device via the bidirectional communication line A file transmission apparatus in a download system comprising: multiplexing means, blocking means, and file transmission means.

  According to such a configuration, the file transmitting device receives the content and the connection control information indicating the connection conditions that allow the file receiving device to connect to the complementary server by the multiplexing unit, and multiplexes the content and the connection control information. To do. In addition, the file transmission device generates a file in which the content multiplexed by the multiplexing unit and the connection control information are blocked in a predetermined size by the blocking unit. Then, the file transmission device transmits the file generated by the blocking unit to the file reception device by the file transmission unit.

  That is, the file transmission device transmits a file including connection control information indicating connection conditions connectable to the complementary server to the file reception device. For example, a connection condition is set such that only a file reception device having a certain amount of content loss can be connected to the supplement server, or the time for connecting a plurality of file reception devices to the supplement server is allocated. By providing the connection conditions in this way, the file transmission device can prevent a large number of file reception devices from connecting to the complementary server in a short time.

  The file transmission device according to claim 2 is the file transmission device according to claim 1, wherein the multiplexing unit has an upper limit deficit amount indicating a content and an upper limit amount of a deficient portion that the file reception device can connect to the complementary server. The connection control information is multiplexed.

  According to such a configuration, the file transmission device can prevent a file receiving device in which a content loss greater than the upper-limit loss amount has occurred, which imposes a heavy load on the complementary server, from connecting to the complementary server.

  The file transmission device according to claim 3 is the file transmission device according to claim 2, wherein the multiplexing means designates the content and a time zone in which the file reception device can connect to the complementary server in accordance with the missing amount The connection control information including the connection time zone is multiplexed.

  According to such a configuration, for example, the file transmission device is connected to the complementary server at night using the designated connection time zone at night as the file reception device in which a large amount of loss has occurred so as to affect content viewing. Let In addition, for example, the file transmission apparatus causes a file reception apparatus with a small amount of loss to be connected to the complementary server in the daytime with the daytime as the designated connection time zone. In this way, the file receiving device is assigned the time to connect to the complementary server according to the missing amount.

  In order to solve the above-described problem, a file receiving apparatus according to claim 4 includes a file transmitting apparatus that transmits a file via a unidirectional communication line that is digital broadcasting or multicast communication, and at least one file that receives the file. Complementing the file receiving device and the block content stored in the file, and transmitting the block corresponding to the missing portion of the content that the file receiving device could not receive to the file receiving device via the bidirectional communication line A file receiving apparatus in a download system comprising a server, comprising: a file receiving means, a content loss judging means, a complementary server connection judging means, and a content complementing means.

  According to such a configuration, the file receiving apparatus transmits a file in which content and connection control information indicating connection conditions that allow the file receiving apparatus to connect to the complementary server are multiplexed and blocked by the file receiving unit. Receive from the device. Further, the file receiving apparatus determines the block corresponding to the missing portion of the content included in the file received by the file receiving means by the content missing determining means. Then, the file receiving device acquires the connection control information included in the file by the complementary server connection determination means, and determines that the connection to the complementary server is possible when the connection condition of the connection control information is satisfied. Further, the file receiving device requests the complementary server to transmit a block corresponding to the missing part when the content complementing unit determines that it can be connected to the complementary server, and the block transmitted from the complementary server in response to the request. Use to complement the content.

  That is, the file receiving apparatus connects to the supplement server only when the connection condition that allows connection to the supplement server is satisfied. Here, for example, a connection condition is set such that only a file receiving device having a certain amount of missing content can be connected to the complementary server, or a time for connecting a plurality of file receiving devices to the complementary server is allocated. By connecting to the complementary server according to the connection conditions in this way, it is possible to prevent a large number of file receiving apparatuses from connecting to the complementary server in a short time.

  The file receiving device according to claim 5 is the file receiving device according to claim 4, wherein the file receiving means is a file in which connection control information indicating an upper limit missing amount which is an upper limit amount of a missing portion is multiplexed and blocked The content deficiency determination means calculates a content deficiency amount, and the complement server connection determination means determines that connection to the complement server is possible when the content deficit amount is less than the upper limit deficiency amount. To do.

  According to such a configuration, the file receiving apparatus can prevent connection to the supplement server when content loss exceeding the upper limit defect amount that gives a heavy load to the supplement server has occurred.

  The file reception device according to claim 6 is the file reception device according to claim 5, wherein the file reception means includes a designated connection time zone in which a time zone that can be connected to the supplementary server is designated according to the amount of missing content. Receiving the file in which the connection control information is multiplexed and blocked, the complementary server connection determining means acquires time information and determines that it is connectable to the complementary server when the time information is in the designated connection time zone. It is characterized by.

  According to such a configuration, for example, when a missing amount that affects the viewing of content has occurred, the file reception device connects to the complementary server at night using the night as the designated connection time zone. Further, for example, when there is a missing amount, the file receiving apparatus connects to the complementary server in the daytime with the daytime as the designated connection time zone. As described above, the file receiving apparatus distributes the time to connect to the complementary server in accordance with the missing amount.

According to the present invention, the following excellent effects can be obtained.
According to the first aspect of the present invention, the file transmission device transmits a file including connection control information indicating connection conditions connectable to the complementary server to the file reception device. By providing connection conditions in this way and transmitting, the file transmission device can prevent a large number of file reception devices from connecting to the complementary server in a short time, thus enabling a download service via a unidirectional communication line. In addition, it is possible to supplement the missing portion of the content with a supplement server having a simple configuration.

  According to the invention of claim 2, the file transmission device connects the supplementary server to the file reception device in which the content loss of the upper limit missing amount or more that gives a heavy load to the supplementary server occurs. Since it can prevent, the structure of a complementary server can be simplified.

  According to the invention of claim 3, since the file transmission device causes the file reception device to distribute the connection time to the complementary server according to the amount of missing content, the user can reduce the load on the complementary server while minimizing the load on the complementary server. Can be secured.

  According to the invention which concerns on Claim 4, a file reception apparatus will be connected to a complement server, when the connection conditions which can be connected to a complement server are satisfy | filled. By providing connection conditions in this way, it is possible to prevent a large number of file receiving apparatuses from connecting to the complementary server in a short time, so that it is possible to provide a download service via a unidirectional communication line and a simple configuration. With the supplement server, the missing part of the content can be supplemented.

  According to the invention of claim 5, the file receiving apparatus can prevent connection to the supplement server when content loss exceeding the upper limit defect amount has occurred, which imposes a heavy load on the supplement server. The configuration of the complementary server can be simplified.

  According to the invention of claim 6, since the file receiving device distributes the connection time to the complementary server according to the amount of missing content, the convenience of the user is ensured while minimizing the load on the complementary server. it can.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each embodiment, means having the same function and the same member are denoted by the same reference numerals, and description thereof is omitted.

[Configuration of file sending device]
With reference to FIG. 1, the structure of the file transmission apparatus which concerns on this embodiment of this invention is demonstrated. FIG. 1 is a block diagram showing the configuration of a file transmission apparatus according to this embodiment of the present invention. As shown in FIG. 1, the file transmission apparatus 1 transmits a file via a unidirectional communication line M, and includes a containerization means (multiplexing means) 11, a blocking means 13, and a file transmission means. 15.

  The containerization means (multiplexing means) 11 receives contents and connection control information and containers (multiplexes) the contents and connection control information. In the present embodiment, the containerization means 11 containers the content, connection control information, header, and metadata in the format of “ISO / IEC 14496-12 ISO based media file format”. The containerization means 11 corresponds to the multiplexing means described in the claims.

  Here, the content is, for example, video, music, or music encoded in MPEG (Moving Picture Experts Group) -2 TS (Transport Stream), MP4, or 3GPP format. The file data structure will be described later.

  The blocking unit 13 generates a file in which the contents containerized by the containerizing unit 11 and the connection control information are blocked in a preset size. In the present embodiment, the blocking unit 13 uniquely includes each content block, including content, connection control information, a header, and metadata so that each block is 5 Kbytes to 5 Mbytes. A block ID to be identified is assigned to each block to generate a file.

  The file transmission unit 15 transmits the file generated by the blocking unit 13 to the file reception device 2 (see FIG. 5). In this embodiment, the file transmission means 15 transmits a file by the “ISO / IEC13818-6 DSM-CC data carousel system” via the unidirectional communication line M which is digital broadcasting such as BS digital broadcasting and mobile broadcasting. . In the present invention, as the unidirectional communication line M, IP multicast communication (IP multicast broadcast), which is a unidirectional communication method similar to digital broadcasting, can be used.

  The file transmitting apparatus 1 can be configured by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an HDD (Hard Disk Drive). Further, the file transmission device 1 may include an antenna (not shown) for transmitting BS digital broadcast or mobile broadcast.

<File data structure>
Hereinafter, the data structure of the file in the present invention will be described with reference to FIG. 2 (see FIG. 1 as appropriate). 2A and 2B are diagrams showing a data structure of a file in the present invention. FIG. 2A shows a case where connection control information and media data are containerized into one file, and FIG. 2B shows connection control information and media. This is a case where data and data are containerized.

As shown in FIG. 2, the header is, for example, content type (format) information.
The connection control information indicates connection conditions that allow a file receiving device (not shown) to connect to a supplement server (not shown). This connection control information includes, for example, connection conditions set in advance according to the type of communication line used for the service, the number of file reception devices, the frequency of occurrence of content loss, and the time zone.
The metadata includes, for example, a content ID that uniquely identifies the content, a content capacity, content title information, and content copyright information.
Furthermore, the media data is, for example, data that becomes the content.

  Here, as shown in FIG. 2A, in the blocking unit 13, a header, metadata, connection control information, and content (media data) may be included in one file. In this case, the file transmission means 15 only needs to perform the transmission process for one file, and the transmission process is simplified.

  On the other hand, as shown in FIG. 2B, the blocking unit 13 is a file including a header, metadata, and contents (media data), a file including a header, metadata, and connection control information. May be separate. Here, in order to associate the connection control information with the content, the metadata of both files in FIGS. 2A and 2B includes a content ID of the same value. By doing in this way, the file transmission means 15 can transmit connection control information and a content at a separate timing.

<Details of connection control information>
Hereinafter, the details of the connection control information in the present invention will be described with reference to FIG. 3 (see FIG. 1 as appropriate). FIG. 3 is a diagram for explaining the details of the connection control information in the present invention.

  The connection control information is, for example, a table as shown in FIG. 3, and the upper limit missing amount includes an upper limit of missing blocks that is the upper limit of the number of missing blocks connectable to the complementary server. Here, if this missing portion is received from the supplement server in a state where the missing amount of content is too large, the load on the complement server increases. For this reason, the file transmission apparatus 1 can prevent such a situation by setting this upper limit missing amount.

  In the example of FIG. 3, since the upper limit of the number of missing blocks is 2000, the file receiving apparatus does not connect to the complementary server when 2000 or more blocks are missing. Note that the upper limit defect size (for example, 20 Mbytes) of the missing content may be used as the upper limit defect amount (not shown). Note that the upper limit of the number of missing blocks is not particularly limited.

  In the example of FIG. 3, the connection control information includes a designated connection time zone in order to distribute the time to connect to the complementary server according to the content loss amount. Here, the number of missing blocks indicating the number of missing blocks is used as the amount of missing contents. Further, the connectable time zone is divided between the case where the number of missing blocks is less than 1000 and the case where the number of missing blocks is 1000 or more. Furthermore, the connectable time zone may be distributed depending on whether the number of missing blocks is an odd number or an even number.

  For example, when the number of missing blocks is less than 1000 and the number of missing blocks is an odd number, the connectable time zone is from 0:00 to 12:00. Further, when the number of missing blocks is less than 1000 and the number of missing blocks is an even number, the connectable time zone is from 12:00 to 24:00. Further, the connectable time zone when the number of missing blocks is 1000 or more and less than 2000 is 22:00 to 6:00. Although the number of missing blocks is used as the missing amount, a missing size (for example, 10 Mbytes) indicating the size of the missing content may be used (not shown). Note that the number of missing blocks and the connectable time zone are not limited to the example in FIG. 3, depending on the type of communication line used for the service, the number of file reception devices, the frequency of occurrence of content loss and the time zone, Can be set arbitrarily.

[Operation of file sending device]
The operation of the file transmission apparatus of FIG. 1 will be described with reference to FIG. 4 (see FIG. 1 as appropriate). FIG. 4 is a flowchart showing the operation of the file transmission apparatus of FIG.

  First, the file transmission device 1 receives the content and the connection control information by the containerization means 11 and containers the content and the connection control information (step S11: containerization step). Next, the file transmission apparatus 1 generates a file in which the content and connection control information containerized by the containerization unit 11 are blocked by the blocking unit 13 in a predetermined size (step S12: blockization). Step). Furthermore, the file transmission device 1 transmits the file generated by the blocking unit 13 to the file reception device 2 by the file transmission unit 15 (step S13: file transmission step).

[Configuration of file receiver]
With reference to FIG. 5, the structure of the file receiver which concerns on this embodiment of this invention is demonstrated. FIG. 5 is a block diagram showing the configuration of the file receiving apparatus according to this embodiment of the present invention. As shown in FIG. 5, the file receiving apparatus 2 receives a file via a unidirectional communication line M, and includes a file receiving unit 21, a file storage unit 22, a content check unit (content missing determination unit). ) 23, supplement server connection determination means 24, and content complement means 25.

  The file receiving means 21 receives a file in which contents and connection control information are multiplexed and blocked via the unidirectional communication line M from the file transmitting apparatus 1 (see FIG. 1). In the present embodiment, the file receiving means 21 receives a file having a data structure as shown in FIG.

  The file storage unit 22 stores the file received by the file reception unit 21 and is, for example, an HDD (Hard Disk Drive) or a RAM (Random Access Memory). Here, for example, when a missing part is included in the content of the received file due to rain attenuation, the block ID corresponding to this missing part is accumulated in the file accumulating unit 22 in a missing state.

  The content check means (content loss determination means) 23 includes content integrity confirmation means 23a and loss amount measurement means 23b. The content check unit 23 corresponds to the content loss determination unit described in the claims.

  The content integrity confirmation unit 23a determines whether or not the content included in the file is missing. In the present embodiment, the content integrity confirmation unit 23a refers to the file storage unit 22, calculates CRC data and a hash value for each block, and determines whether the content is missing. When the content integrity confirmation unit 23a determines that the content is missing, the content integrity confirmation unit 23a requests the missing amount measurement unit 23b to determine a block corresponding to the missing part of the content.

  The missing amount measuring unit 23b determines a block corresponding to the missing portion of the content included in the file and calculates the missing amount of the content in response to a request from the content integrity checking unit 23a. In the present embodiment, the missing amount measuring unit 23b refers to the file storage unit 22, and if there is something missing from the content block ID, the content integrity checking unit 23a uses the block ID corresponding to the missing portion as identification information. To the complementary server connection determination means 24. At this time, the missing amount measuring unit 23b calculates, for example, the number of missing blocks as a missing amount of content, and outputs it to the complementary server connection determining unit 24 via the content integrity checking unit 23a.

  The complementary server connection determination unit 24 acquires connection control information included in the file, and determines that connection to the complementary server is possible when the connection condition of the connection control information is satisfied. In the present embodiment, the complementary server connection determination unit 24 acquires time information from, for example, an NTP (Network Time Protocol) or a built-in clock of the file reception device 2. Then, the complementary server connection determination unit 24 determines whether or not the connection condition is satisfied based on the block ID (identification information) corresponding to the missing portion from the content check unit 23 and the acquired connection control information and time information. judge.

  Specifically, as described with reference to FIG. 3, the complementary server connection determination unit 24 may determine that the connection condition is satisfied when the content loss amount is less than the upper limit loss amount. At this time, if the time information is in the designated connection time zone according to the missing amount, the complementary server connection determination unit 24 may determine that the connection condition is satisfied. Then, when this connection condition is satisfied, the complementary server connection determination unit 24 determines that connection to the complementary server 3 is possible, and outputs a block ID (identification information) corresponding to the missing portion to the content complementing unit 25. On the other hand, if it is determined that the connection condition is not satisfied, the complementary server connection determination unit 24 may not output the identification information to the content complementing unit 25.

  The content complementing unit 25 includes a complementing server connection control unit 25a and a content repairing unit 25b.

  The complementary server connection control means 25a requests the complementary server 3 to transmit a block corresponding to the missing portion of the content, and receives a block transmitted from the complementary server 3 in response to this request. In the present embodiment, the complementary server connection control means 25a outputs the supplemental server connection determination means 24 together with the above request using the TCP / IP (Transmission Control Protocol / Internet Protocol) protocol via the bidirectional communication line N. The block ID (identification information) is transmitted to the complement server 3. Further, the complementary server connection control unit 25 a receives a block corresponding to the missing portion of the content from the complementary server 3.

  The content repair unit 25b supplements (repairs) the content included in the file stored by the file storage unit 22 using the block received by the supplement server connection control unit 25a.

  The file receiving device 2 can be configured by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an HDD (Hard Disk Drive). Further, the file receiving device 2 may include an antenna (not shown) for receiving BS digital broadcasting or mobile broadcasting.

[Operation of file receiver]
With reference to FIG. 6, the operation of the file receiving apparatus of FIG. 5 will be described (see FIG. 5 as appropriate). FIG. 6 is a flowchart showing the operation of the file receiving apparatus of FIG.

  First, the file receiving device 2 receives a file in which contents and connection control information are multiplexed and blocked by the file receiving means 21 from the file transmitting device 1 (step S21: file receiving step). Then, the file receiving device 2 stores the file received by the file receiving unit 21 by the file storing unit 22 (step S22: file storing step).

  Following the processing of step S22, the file receiving apparatus 2 determines whether or not the content included in the file is missing by the content integrity checking unit 23a, and the content included in the file by the missing amount measuring unit 23b. The block corresponding to the missing portion is determined (step S23: content check step).

  Subsequent to the processing in step S23, the file reception device 2 acquires connection control information included in the file by the complementary server connection determination unit 24, and can connect to the complementary server 3 when the connection control information connection condition is satisfied. (Step S24: complementary server connection determination step).

  Subsequent to the processing of step S24, the file receiving device 2 requests the supplement server 3 to transmit a block corresponding to the missing portion of the content by the supplement server connection control means 25a, and the block transmitted from the supplement server 3 is received. Receive. Then, the file receiving device 2 repairs (complements) the content included in the file stored in the file storage unit 22 by using the block transmitted from the supplement server 3 in response to this request by the content repair unit 25b ( Step S25: content complementing step).

[Complementary server configuration]
With reference to FIG. 7, the structure of the complementary server which concerns on this embodiment of this invention is demonstrated (refer FIG.1,5 suitably). FIG. 7 is a block diagram showing the configuration of the complementary server according to this embodiment of the present invention. As shown in FIG. 7, the complementary server 3 transmits a block corresponding to the missing portion to the file receiving device 2, and includes a complementary data storage unit 31, a complementary data extraction unit 33, and a file receiving device connection unit 35. With.

  The complementary data storage unit 31 is an HDD, a RAM, or the like that stores content as complementary data. In the present embodiment, the complementary server 3 receives a file from the file transmission device 1 via a unidirectional communication line (not shown). Then, the complement server 3 stores the received file in the supplement data storage unit 31. Further, the complement server 3 may read content stored in a recording medium such as a DVD and store the content in the supplement data storage unit 31. At this time, it is preferable that the complementary data storage unit 31 stores the content in a block form by assigning a block ID similarly to the blocking unit 13 of FIG.

  The complementary data extracting unit 33 extracts, from the complementary data accumulating unit 31, a block corresponding to the missing portion of the content corresponding to the identification information received by the complementary data extracting unit 33 described later as complementary data. In the present embodiment, the complementary data extraction unit 33 refers to the complementary data storage unit 31 and extracts a block that matches the block ID transmitted from the file reception device 2 as complementary data.

  The file receiving device connecting unit 35 receives identification information indicating a missing portion from the file receiving device 2 via the bidirectional communication line N and outputs it to the complementary data extracting unit 33. Further, the file receiving device connecting unit 35 transmits the complementary data extracted by the complementary data extracting unit 33 to the file receiving device 2.

  According to this embodiment, since only the file receiving device 2 that satisfies the connection condition is connected to the complementary server, a large number of file receiving devices 2 can be prevented from connecting to the complementary server 3 in a short time, and the unidirectional communication line M In addition, the download service can be performed via the server, and the missing part of the content can be supplemented by the supplement server 3 having a simple configuration.

It is a block diagram which shows the structure of the file transmission apparatus which concerns on this embodiment of this invention. It is a figure which shows the data structure of the file in this invention, (a) is a case where connection control information and media data are containerized into one file, (b) is a connection control information and media data separately. This is a case of containerizing the file. It is a figure explaining the detail of the connection control information in this invention. It is a flowchart which shows operation | movement of the file transmission apparatus of FIG. It is a block diagram which shows the structure of the file receiver which concerns on this embodiment of this invention. It is a flowchart which shows operation | movement of the file receiver of FIG. It is a block diagram which shows the structure of the complement server which concerns on this embodiment of this invention.

Explanation of symbols

1 File transmission device 11 Containerization means (multiplexing means)
13 Blocking means 15 File sending means 2 File receiving device 21 File receiving means 22 File storing means 23 Content checking means (content missing judging means)
23a Content completeness confirmation means 23b Missing amount measurement means 24 Complementary server connection determination means 25 Content complementation means 3 Supplementary server 31 Supplementary data storage means 33 Supplementary data extraction means 35 File reception device connection means M Unidirectional communication line N Bidirectional communication line

Claims (6)

A file transmission device that transmits a file via a unidirectional communication line that is digital broadcasting or multicast communication, one or more file reception devices that receive the file, and blocks and accumulates content included in the file, A file transmission device in a download system comprising a complementary server that transmits to the file reception device a block corresponding to a missing portion that could not be received by the file reception device in the content via a bidirectional communication line,
Multiplexing means for receiving the content and connection control information indicating connection conditions that allow the file receiving device to connect to the complementary server and multiplexing the content and the connection control information;
Blocking means for generating the file obtained by blocking the content multiplexed by the multiplexing means and the connection control information with a preset size;
File transmitting means for transmitting the file generated by the blocking means to the file receiving device;
A file transmission device comprising:   The multiplexing means multiplexes the content and the connection control information including an upper limit missing amount indicating an upper limit amount of the missing portion that can be connected to the complementary server by the file receiving device. Item 2. The file transmission device according to Item 1.   The multiplexing means multiplexes the content and the connection control information including a designated connection time zone in which a time zone in which the file receiving apparatus can connect to the complementary server is designated according to a missing amount of the content. The file transmission apparatus according to claim 2. A file transmission device that transmits a file via a unidirectional communication line that is digital broadcasting or multicast communication, one or more file reception devices that receive the file, and blocks and accumulates content included in the file, A file receiving device in a download system comprising a complementary server that transmits a block corresponding to a missing portion that could not be received by the file receiving device in the content to the file receiving device via a bidirectional communication line,
File receiving means for receiving from the file transmission device the file in which the content and connection control information indicating connection conditions that allow the file receiving device to connect to the complementary server are multiplexed and blocked;
Content loss determination means for determining a block corresponding to a missing portion of the content included in the file received by the file reception means;
When acquiring the connection control information included in the file and satisfying the connection condition of the connection control information, complementary server connection determination means for determining that connection to the complementary server is possible;
When it is determined that connection to the complement server is possible, the content is requested using the block transmitted from the complement server in response to the request while requesting the complement server to transmit the block corresponding to the missing portion. Content complementing means to complement
A file receiving apparatus comprising: The file receiving means receives the file in which the connection control information indicating the upper limit missing amount which is the upper limit amount of the missing part is multiplexed and blocked,
The content loss determination means calculates the amount of content loss,
The file receiving apparatus according to claim 4, wherein the complementary server connection determination unit determines that connection to the complementary server is possible when the missing amount of the content is less than the upper limit missing amount. The file receiving means receives the file in which the connection control information including a designated connection time zone in which a time zone that can be connected to the complementary server is designated according to the amount of missing content is multiplexed and blocked,
The file reception according to claim 5, wherein the complementary server connection determination unit acquires time information and determines that connection to the complementary server is possible when the time information is in the designated connection time zone. apparatus.

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