JP5789450B2 - Content distribution system, content distribution server, cache server, and programs thereof - Google Patents

Description

The present invention relates to a content distribution system for a viewer to view a broadcast program (content) via a network, a content distribution server, a cache server , and their programs.

Conventionally, a viewing mode for viewing a broadcast program is that a viewer (hereinafter referred to as a user) views a broadcast program (hereinafter referred to as a content) distributed in accordance with the program organization in real time, and the user can select an arbitrary timing. A viewing mode for viewing content is realized.
For example, a hard disk recorder capable of time-shifted viewing that stores broadcast content as a file in a storage medium and designates the content for viewing at a user's favorite time is common. In addition, video-on-demand is also common in which a TV program, a radio program, or a movie is downloaded and viewed as a file via a network.

As described above, various techniques for reproducing content from an arbitrary position (scene) selected by the user in a form in which the user views the content at an arbitrary timing are disclosed (see Patent Documents 1 to 5).
For example, Patent Literature 1 discloses a technique for reading and reproducing moving image information by skipping the reading position of moving image information stored in a storage medium by a specified time before or after.
In Patent Document 2, content distributed via a network is stored in a storage medium, a user designates a desired program from a program guide published on a website or network, and broadcast date and broadcast time. A technique for reproducing content from an arbitrary position of a desired program by designating is disclosed.

In Patent Document 3, as time-shifted viewing, the entire content is stored in the receiver, or a part of the content desired by the user is stored, and then played back by random access, or only the desired scene by the user is stored. A technique for viewing and listening many times is disclosed.
In Patent Document 4, video data separately prepared for zapping is stored in order to perform zapping viewing in broadcasting over an IP network that performs packet transmission, and the video data is reproduced when zapping is performed. Thus, a technique for shortening the waiting time until content reproduction due to network delay and realizing high-speed zapping is disclosed.
Japanese Patent Application Laid-Open No. 2004-133867 has a technology in which content existing on a network is virtually arranged on a time axis corresponding to real time for each predetermined group, and the content is switched and reproduced in units of groups on the time axis. It is disclosed.

JP 2002-223408 A JP 2007-228619 A Japanese Patent No. 4446249 Japanese Patent No. 4443833 JP 2010-28433 A

In the techniques described in Patent Documents 1 to 4, in order to reproduce content from an arbitrary scene, the content or a part thereof must be stored in advance in a storage medium (memory, hard disk, etc.) in the apparatus. Don't be.
However, there is a demand not only for the contents but also for accessing contents broadcast in the past as broadcast programs along the broadcast time that is the organization information, that is, for zapping in the time direction.

  In this case, in the conventional technology, the content that can be accessed by changing the scene that the user wants to view is the content (or a part thereof) stored in the storage medium, and the other content is accessed retroactively from the broadcast time. I can't do it. For example, even if a plurality of contents are stored in a storage medium in order to access other contents retroactively, the broadcast time of the contents that the user desires to access is undecided at the present time. In reality, it is impossible to store all the contents that are accessed and store all the contents in the user's viewing device.

  On the other hand, the technique described in Patent Document 5 acquires content to be viewed via a network, and enables zapping in units of groups. For example, if the group is one channel (broadcast station), zapping for each channel can be performed for a broadcast program distributed via a network. However, since this conventional technique is a technique for switching contents for each channel, there is a problem that it is impossible to specify and access the broadcast time of the organization information for the contents broadcast as a broadcast program.

The present invention has been made in view of the above-described problems, and when viewing content distributed as a broadcast program via a network, the content is accessed by designating a broadcast time as organization information. It is an object of the present invention to provide a content distribution system that can be used, a content distribution server, a cache server , and a program thereof.

  The present invention was created to solve the above-mentioned problems. First, the content distribution system according to claim 1 connects a content distribution server, a cache server, and a content viewing apparatus via a network. A content distribution system that distributes content from the content distribution server to the content viewing device via the cache server according to preset organization information, and distributes content specified from the content viewing device. The content distribution server includes content storage means, organized program data transmission means, first data request reception means, and designated program data transmission means, and the cache server includes data storage means, Data receiving means, second data request accepting means, and search execution And stage were the data request unit, and a data transmitting unit, configured to include a.

  In this configuration, the content distribution system stores a plurality of contents in the content storage unit of the content distribution server. This content storage means stores content distributed in the past and content scheduled to be distributed in the future.

  Further, the content distribution system divides the content to be distributed according to the organization information into block data having a predetermined time length by the organized program data transmission means of the content delivery server, and adds the block identification content to which the channel identification and the broadcast time are added. Generated and transmitted as organized program data to the cache server. Here, the channel identification is identification information for identifying a broadcast channel in content organization. Also, the broadcast time is a reproduction time in the organization of block data. With this channel identification and broadcast time, it is possible to specify which part of which content data (block data) is organized.

Also, the content distribution system receives a data request designating channel identification and broadcast time from the cache server by the first data request receiving means of the content distribution server.
Then, the content distribution system sends data corresponding to the channel identification and broadcast time specified by the data request received by the first data request receiving means based on the organization information by the designated program data transmission means of the content distribution server. Blocked content read from the content storage means and added with the channel identification and broadcast time is generated, and transmitted to the requested cache server as designated program data. At this time, the time length of the data read from the content storage means by the designated program data transmission means is the same as the time length during which the organized program data transmission means divides the content. As a result, the content data (organized program data) according to the organization and the requested content data (designated program data) are transmitted to the cache server as data of the same time length, and the data is transmitted to the cache server. Can be managed in common.

  Further, the content distribution system receives the organized program data and designated program data, which are blocked contents transmitted from the content distribution server, by the data receiving unit of the cache server, and stores them in the data storage unit. This data storage means temporarily stores the blocked content, and for example, deletes old data when the data amount exceeds a predetermined maximum storage capacity.

In addition, the content distribution system accepts a data request for the designated program data specifying the program identification data or channel identification and broadcast time according to the composition from the content viewing apparatus by the second data request accepting means of the cache server.
Then, when the content distribution system requests the designated program data by specifying the channel identification and the broadcast time in the data request received by the second data request receiving means by the search execution means of the cache server, Using the identification and broadcast time as a search key, the designated program data is retrieved from the data storage means.

Then, the content distribution system specifies the channel identification and the broadcast time as search keys when the requested execution program data is not searched in the search execution unit by the data request unit of the cache server, and the content distribution system Request specified program data from the server. Thus, a data request is made to the content distribution server only when there is no requested data in the cache server.
Then, the content distribution system uses the data transmission means of the cache server to view the designated program data searched by the search execution means, or the organized program data or the designated program data received by the data receiving means, for viewing the content that requested the data. Send to device.

  Thereby, for the blocked content (organized program data) according to the composition, the data received by the data receiving means is transmitted as it is from the data transmitting means to the content viewing device. On the other hand, if the block content (designated program data) specified by the broadcast time or the like is not related to the organization, if it exists in the cache server, the data is transmitted to the content viewing device. The data received from the content distribution server in response to the request is transmitted to the content viewing apparatus.

  Furthermore, the content delivery system according to claim 2 is the content delivery system according to claim 1, wherein the search execution means searches for the designated program data corresponding to the search key with another cache server. Yes, the second data request accepting means accepts a request for designated program data from another cache server. In the search execution means, designated program data corresponding to the search key is stored in the data storage means. When the data is stored in another cache server, the data requesting unit requests the designated program data from the other cache server.

  In such a configuration, the content distribution system, in the search execution means of the cache server, if the designated program data requested in the cache server does not exist, the content distribution system requests the cache server by expanding the search range to other cache servers. Attempt to retrieve recorded data. As a result, requests to the content distribution server can be reduced, and the load on the content distribution server can be reduced.

  Further, the content distribution server according to claim 3 connects the content distribution server, the cache server, and the content viewing device via a network, and from the content distribution server to the cache server in accordance with preset organization information. The content distribution server in the content distribution system that distributes the content to the content viewing device via the network and distributes the content designated from the content viewing device, wherein the content storage unit and the organized program data transmission unit And a data request receiving unit and a designated program data transmitting unit.

  In such a configuration, the content distribution server stores content distributed in the past and content scheduled to be distributed from now on in the content storage means. Then, the content distribution server divides the content to be distributed according to the organization information by the organization program data transmission means into block data having a predetermined length of time, and generates block content that adds the channel identification and the broadcast time, It is transmitted to the cache server as organized program data.

Further, the content distribution server receives a data request designating channel identification and broadcast time from the cache server by the data request receiving means.
Then, the content distribution server reads the data corresponding to the channel identification and broadcast time specified by the data request received by the data request receiving unit from the content storage unit based on the organization information by the designated program data transmitting unit. Blocked content with channel identification and broadcast time added is generated and transmitted as specified program data to the requested cache server.

  Further, as in the content distribution program according to claim 4, a content distribution server including a content storage unit that stores a plurality of contents, a cache server, and a content viewing apparatus are connected via a network and set in advance. The content distribution in the content distribution system that distributes the content from the content distribution server to the content viewing device via the cache server and distributes the specified content from the content viewing device according to the organized information The computer of the server may be operated by a content distribution program that functions as an organized program data transmission unit, a data request reception unit, and a designated program data transmission unit.

  The cache server according to claim 5 connects the content distribution server, the cache server, and the content viewing apparatus via a network, and from the content distribution server via the cache server according to preset organization information. The cache server in the content distribution system that distributes the content to the content viewing device and distributes the content specified from the content viewing device, the data storage unit, the data reception unit, and the data request reception Means, search execution means, data request means, and data transmission means.

In such a configuration, the cache server receives the blocked content transmitted from the content distribution server by the data receiving means, and stores it in the data storage means.
In addition, the cache server receives a data request from the content viewing apparatus by the data request accepting unit for the organized program data that is the blocked content according to the organization or the designated program data that is the blocked content specifying the channel identification and the broadcast time. Accept.

  The cache server searches the channel identification and broadcast time when the designated program data is requested by specifying the channel identification and the broadcast time by the data request received by the data request accepting means by the search execution means. As the key, the designated program data corresponding to the search key is searched between the data storage means and another cache server connected to the network.

When the requested execution program data is not searched by the search execution means by the data requesting means, the cache server designates the channel identification and the broadcast time as the search keys, and designates the designated program to the content distribution server. Request data.
Then, the cache server transmits the designated program data retrieved by the retrieval execution unit, or the organized program data or the designated program data received by the data receiving unit, to the content viewing apparatus that requested the data by the data transmission unit. .

  Further, as in the cache program according to claim 6, a content distribution server, a cache server having a data storage means for temporarily storing content, and a content viewing apparatus are connected via a network, and The cache in a content distribution system that distributes content from the content distribution server to the content viewing device via the cache server and distributes content specified from the content viewing device according to set organization information The server computer may be operated as a cache program that functions as a data reception unit, a data request reception unit, a search execution unit, a data request unit, and a data transmission unit.

The present invention has the following excellent effects.
According to the first aspect of the present invention, the content can be accessed along the time direction by designating the broadcast time of the organization information without storing the content in the content viewing device. As a result, a user who views content on the content viewing apparatus can view the viewed content retroactively in the time direction or change the playback position within the content.

  According to the second aspect of the present invention, when there is a request specifying the channel identification and the broadcast time from the content viewing apparatus, if the data is stored in any of the plurality of cache servers, the content distribution is performed. No requests are made to the server. As a result, the load on the content distribution server can be reduced.

  According to the third and fourth aspects of the invention, not only can content be distributed according to the organization information, but also content requested from the content viewing apparatus can be distributed via the cache server. As a result, the content viewing apparatus can reproduce the content retroactively without storing the content.

  According to the fifth and sixth aspects of the present invention, the blocked content distributed by the content distribution server is temporarily stored. Therefore, when a request is received from the content viewing apparatus, the requested data is reproduced again. It is possible to transmit, and the required load on the content distribution server can be suppressed. According to the fifth and sixth aspects of the invention, even if there is no corresponding data in the cache server, if the data exists in another cache server, the data is sent to the content viewing device. Since transmission is performed, the load on the content distribution server can be further reduced.

1 is a system configuration diagram showing an overall configuration of a content distribution system according to an embodiment of the present invention. It is explanatory drawing for demonstrating the relationship between the present time and designated time in organization information. It is a block block diagram which shows the structure of the content delivery server which concerns on embodiment of this invention. It is a data structure figure which shows an example of the blocked content which a content delivery server delivers. It is a block block diagram which shows the structure of the cache server which concerns on embodiment of this invention. It is a block block diagram which shows the structure of the content viewing-and-listening apparatus which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the content delivery server which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the cache server which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the content viewing-and-listening apparatus which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
[Content distribution system configuration]
First, an overall configuration of a content distribution system according to an embodiment of the present invention will be described with reference to FIG.

  The content distribution system S shown in FIG. 1 distributes the content (broadcast program) to the content viewing apparatus 3 according to the organization (organization information) of the broadcast program so that the user can view the content and view the content. This allows the user to view the content retroactively without accumulating the content in the device 3.

Here, the content distribution system S is configured by connecting the content distribution server 1 and a plurality of cache servers 2 (2 ₁ , 2 ₂ ,..., 2 _m ) via a network. In addition, a plurality of content viewing apparatuses 3 (3 ₁ , 3 ₂ ,..., 3 _n ) are connected to each cache server 2 via a network.

  The content distribution server 1 transmits data to a predetermined cache server as data (organized program data) obtained by sequentially blocking the content in accordance with the organization of the broadcast program. In addition, the content distribution server 1 requests content from the cache server 2 by designating a broadcast channel (hereinafter referred to as a channel) and broadcast time, and content data corresponding to the designated channel and broadcast time. (Specified program data) is also transmitted to the requested cache server 2.

  The cache server 2 temporarily stores content according to the organization distributed by the content distribution server 1 and distributes it to the content viewing device 3. In addition, the cache server 2 stores the requested content data (designated program data) in the cache server 2 by requesting the content by designating the channel and the broadcast time from the content viewing device 3. For example, the data is transmitted to the content viewing device 3.

Note that the cache server 2 (for example, 2 ₁ ) has no designated program data in its own server, or the other designated cache server 2 (2 ₂ ,..., 2 _m ) has the designated program data. The data is acquired and transmitted to the content viewing apparatus 3. In addition, when there is no designated program data in the other cache servers 2 (2 ₂ ,..., 2 _m ), the cache server 2 (2 ₁ ) designates the channel and the broadcast time to the content distribution server 1. Then, the designated program data is acquired and transmitted to the content viewing apparatus 3.

  In this way, by configuring the content distribution system S, the user can view the content according to the broadcast program organization on the content viewing device 3, and at the past time (for example, 10 minutes ago, 1 hour ago). The content of the designated channel can be viewed retroactively 1 day ago).

For example, as shown in FIG. 2A, it is assumed that the user is viewing the content B1 of the channel B on the content viewing device 3 among the channels A, B,.
Here, when the user designates a time (absolute time or relative time) before the current time with a remote control device (not shown) in the content viewing device 3, the content B2 at the designated time is stored in the cache server. 2 will be transmitted. That is, the user can perform zapping in the time direction when viewing the content.

  Hereinafter, the configuration and operation of the content distribution server 1 and the cache server 2 constituting the content distribution system S, and the content viewing apparatus 3 for viewing content using this system will be described in detail.

[Content distribution server configuration]
First, the configuration of the content distribution server 1 will be described with reference to FIG. 3 (refer to FIG. 1 as appropriate). As shown in FIG. 3, the content distribution server 1 includes an organization information storage unit 10, a content storage unit 11, an organization program data transmission unit 12, a data request reception unit 13, and a designated program data transmission unit 14. I have.

  The organization information storage means 10 stores organization information in which broadcast time and content are associated with each channel (channel identification). This organization information storage means 10 is a general storage medium such as a hard disk, and organization information created based on program organization is written in advance from the outside. The organization information stored in the organization information storage means 10 includes not only information on the contents distributed at present and in the future, but also information on contents distributed in the past.

  The content storage unit 11 stores content distributed according to the organization information. The content storage means 11 is a general storage medium such as a hard disk, and stores not only current and future content but also content distributed in the past. Note that the content is not limited to video and audio, and the type is not limited as long as it is data distributed according to the organization information, such as data of data broadcasting or character data obtained by converting audio into captions.

  The organized program data transmitting means 12 blocks the content into data at predetermined time intervals and distributes the data to a plurality of predetermined cache servers 2 according to the organized information. It should be noted that the organized program data transmission unit 12 transmits the content earlier than the organization time by a predetermined time so that the content is played back at the organization time at the content viewing device 3. Here, the organization program data transmission unit 12 includes an organization content reading unit 12a, a content division unit 12b, and an organization information addition unit 12c.

The organization content reading unit 12a refers to the organization information stored in the organization information storage unit 10 and reads the content according to the organization of the program from the content storage unit 11. The organization content reading unit 12a identifies the content to be distributed from the organization information for each channel in accordance with the current time measured by the timing unit (not shown), and reads the corresponding content from the content storage unit 11.
The organized content reading unit 12a outputs the read content to the content dividing unit 12b.

The content dividing means 12b divides the content into data (block data) at predetermined time intervals. The content dividing unit 12b divides the content read by the organized content reading unit 12a into predetermined time intervals (for example, one minute intervals).
The content dividing unit 12b outputs the divided block data to the composition information adding unit 12c.

  The organization information adding unit 12c adds the identification information (channel identification) for identifying the channel and the broadcast time on the organization to the content data (block data) divided by the content dividing unit 12b to form a block. The content data (blocked content) is generated. Here, the channel identification is, for example, a unique ID determined by the broadcasting station. In addition, when a broadcast station has a unique ID for each broadcast area, the broadcast area ID may be added to the broadcast station ID.

  For example, as shown in FIG. 4, the organization information adding means 12c includes a channel identification CH composed of a broadcast station ID and a broadcast area ID, and a broadcast time TM composed of information of year, month, day, hour, minute, second Is added to the block data BK as header information H to generate a blocked content.

Here, it is assumed that the header information H includes a delivery identification indicating whether the blocked content is data according to organization information or designated data. That is, the composition information adding unit 12c adds identification information indicating that the data is data according to the composition information to the distribution identification.
Furthermore, the organization information adding unit 12c may include a content ID for identifying content that is the basis of the blocked content in the header information H as shown in FIG.

  The organization information adding unit 12c transmits the generated blocked content to a plurality of predetermined cache servers 2 via a communication transmitting / receiving unit such as a communication board (not shown). The data (blocked content) transmitted by the organized program data transmission means 12 is in accordance with the organization information, and will be referred to as “organized program data” below.

The data request accepting unit 13 accepts a request (data request) for a blocked content not based on the organization information from the cache server 2 via a communication transmitting / receiving unit (not shown). This data request includes channel identification and broadcast time, which are information for specifying the blocked content.
The data request accepting unit 13 outputs the channel identification and broadcast time included in the data request to the designated program data transmitting unit 14 together with information (for example, an IP address) specifying the cache server 2 that requested the data.

  The designated program data transmission unit 14 transmits data corresponding to the channel identification and the broadcast time notified from the data request reception unit 13 to the requested cache server 2. Here, the designated program data transmission means 14 includes block data reading means 14a and organization information addition means 14b.

The block data reading unit 14 a reads the data received by the data request receiving unit 13 from the content storage unit 11. Here, the block data reading unit 14a specifies the content corresponding to the channel identification and the broadcast time included in the data request from the organization information stored in the organization information storage unit 10. Then, the block data reading means 14a reads data (block data) for a predetermined time interval from the content storage means 11 with the requested broadcast time data as the top data in the specified content. This time interval is the same as the time interval for dividing the content by the content dividing means 12b.
The block data reading unit 14a outputs the read block data to the organization information adding unit 14b.

  The organization information adding unit 14b adds identification information (channel identification) for identifying a channel and a broadcast time on organization to the content data (block data) read by the block data reading unit 14a. Blocked content data (blocked content) is generated. The channel identification and the broadcast time are information specified by the data request received by the data request receiving unit 13.

The blocked content generated by the composition information adding means 14b has the same data format (see FIG. 4) as the data transmitted by the composition program data transmitting means 12. The organization information adding unit 14b adds identification information indicating that the data is designated data to the distribution identification of the blocked content described with reference to FIG.
The organization information adding unit 14b transmits the generated blocked content to the cache server 2 that requested the data via a communication transmitting / receiving unit (not shown).
The data (blocked content) transmitted by the designated program data transmission means 14 is in accordance with the designation from the cache server 2 (that is, the designation from the content viewing device 3). It will be called “data”.

Thus, by configuring the content distribution server 1, the content distribution server 1 can transmit the content (blocked content) to the cache server 2 according to the organization information. Further, the content distribution server 1 can transmit the blocked content requested from the cache server 2 without using the organization information.
The content distribution server 1 can operate the computer with a program (content distribution program) that causes the computer to function as each of the means described above.

[Configuration of cache server]
Next, the configuration of the cache server 2 will be described with reference to FIG. 5 (refer to FIG. 1 as appropriate). As shown in FIG. 5, the cache server 2 includes a data receiving unit 20, a data writing unit 21, a data reading unit 22, a data storage unit 23, a data erasing unit 24, a data search / acquisition unit 25, Data management means 26, data request transmission / reception means 27, and data transmission means 28 are provided.

The data receiving means 20 receives the organized program data and designated programs as block contents from the content distribution server 1 and other cache servers 2 (2 ₂ ,..., 2 _m ) different from the cache server 2 (2 ₁ ). Data is received via communication transmitting / receiving means (not shown). Note that the organized program data is blocked content distributed from the content distribution server 1 according to the organization information. The designated program data is block content that is returned when the cache server 2 (2 ₁ ) requests the content distribution server 1 or another cache server 2 (2 ₂ ,..., 2 _m ).
The data receiving means 20 outputs the received blocked content (organized program data, designated program data) to the data writing means 21 and the data transmitting means 28.

  The data writing means 21 writes and stores the blocked contents (organized program data, designated program data) received by the data receiving means 20 in the data storage means 23 as candidates for designated program data to be searched. . Here, the data writing unit 21 writes or writes the blocked content to the data erasing unit 24 at the timing of writing the blocked content into the data storage unit 23 (before or after writing). We will notify you.

  The data reading means 22 reads the blocked content (designated program data) stored in the data storage means 23. Here, the data reading means 22 reads the designated program data requested from the data storage means 23 based on the request from the data search / acquisition means 25.

The data storage means 23 stores the blocked content (organized program data, designated program data) received by the data receiving means 20 as candidates for designated program data to be searched, and the candidates are identified by channel identification and This is stored as a database using broadcast time as a search key.
The data storage means 23 is a general storage medium such as a hard disk. The data writing means 21 and the data reading means 22 execute writing and reading of the blocked content, and the data management means 26 described later designates the data storage means 23. Search for program data is executed. In addition, the data storage unit 23 deletes the blocked content (designated program data) by the data erasing unit 24 described later.

The data erasing unit 24 is for erasing a part of the blocked content stored in the data storage unit 23. In this case, the data erasing unit 24 is configured such that the data amount stored in the data storage unit 23 exceeds the predetermined maximum storage capacity when the writing timing of the blocked content is notified from the data writing unit 21. It is determined whether or not the content is exceeded, and the blocked content is deleted. The method for deleting the blocked content is not particularly limited. For example, the time when the blocked content is written or the time when the blocked content is written is stored in the data storage unit 23, and the writing time or the reading time is read out. Delete the oldest time first.
Here, the data erasing unit 24 operates at the stage when the writing timing of the blocked content is notified from the data writing unit 21, but it operates periodically to determine the data capacity and block the data. The content may be deleted.

The data search / acquisition means 25 searches for the location of the blocked content (designated program data) requested from the content viewing device 3, obtains the designated program data from the location, and requested the content viewing device. 3 is transmitted.
Here, the data search / acquisition means 25 receives a data request indicating a request for designated program data from the content viewing apparatus 3 via the data request transmission / reception means 27, and identifies and broadcasts the channel included in the request. A search request for designated program data is made to the data management means 26 using the time as a key.

When the search result indicating that the location of the requested designated program data is the cache server 2 (2 ₁ ) is notified from the data management means 26, the data search / acquisition means 25 causes the data reading means 22 to Via the data storage means 23, the designated program data is acquired. Then, the data search / acquisition means 25 transmits the designated program data to the requested content viewing apparatus 3 via the data transmission means 28.

Further, when the data management means 26 is notified of a search result indicating that the location of the requested designated program data is one of the other cache servers 2 (2 ₂ ,..., 2 _m ), data search / acquisition The means 25 requests the designated program data to the other cache servers 2 (2 ₂ ,..., 2 _m ) storing the designated program data via the data request transmission / reception means 27. Note that the designated program data returned from the other cache servers 2 (2 ₂ ,..., 2 _m ) is received via the data receiving means 20, and the requested content viewing apparatus via the data transmitting means 28. 3 is transmitted.

Further, when the data management means 26 notifies the search result that the requested designated program data does not exist in all the cache servers 2 (2 ₁ , 2 ₂ ,..., 2 _m ), the data search / acquisition means 25 sends a request for designated program data to the content distribution server 1 via the data request transmission / reception means 27. The designated program data returned from the content distribution server 1 is received via the data receiving means 20 and transmitted to the requested content viewing apparatus 3 via the data transmitting means 28.

Furthermore, here, when the data search / acquisition means 25 receives a data request from another cache server 2 (2 ₂ ,..., 2 _m ) via the data request transmission / reception means 27, the data retrieval means 22 Then, the requested program data requested from the data storage means 23 is read out and transmitted to the other requested cache servers 2 (2 ₂ ,..., 2 _m ) via the data transmission means 28.

The data management means 26 manages the location of the blocked content (designated program data) stored in the cache servers 2 ₁ , 2 ₂ ,..., 2 _m . Here, the data management unit 26 includes a search request receiving unit 26a, a search execution unit 26b, and a search result output unit 26c.

The search request accepting unit 26a accepts a search request for searching for the location of the blocked content (designated program data). This search request is a request including channel identification and broadcast time.
Here, the search request accepting unit 26a accepts a search request from the data search / acquisition unit 25 and also from other cache servers 2 (2 ₂ ,..., 2 _m ) via a communication transmitting / receiving unit (not shown). Accept search requests.
The search request accepting means 26a outputs the channel identification and broadcast time included in the accepted search request to the search executing means 26b using the search keys.

The search execution means 26b searches the designated program data using the channel identification and broadcast time notified from the search request accepting means 26a as search keys.
Here, the search executing means 26b searches the designated program data in the data storage means 23 using the channel identification and the broadcast time as search keys. When the designated program data corresponding to the data storage means 23 is stored, a search result to that effect is output to the search result output means 26c.

When the search execution means 26b receives a search request from the data search / acquisition means 25 and the designated program data corresponding to the data storage means 23 is not stored, the search execution means 26b receives another cache server 2 (2 ₂ , .., 2 _m ), a search request including channel identification and broadcast time notified from the search request receiving means 26a is transmitted via a communication transmitting / receiving means (not shown). The search execution unit 26b, the other cache server _{2 (2} 2, ..., _{2 m)} to get search results from the specified program data other cache server ₂ which stores the ₍₂ 2, ..., _{2 m} ) As a result is output to the search result output means 26c. The retrieval executing means 26b, the other cache server _{2 (2 2, ..., 2} m) even if the designated program data is not stored, the cache server _{2 (2 1, 2 2,} ..., 2 m) The search result output means 26c outputs a search result indicating that the designated program data does not exist.

Here, the search execution means 26b makes a search request to the other cache servers 2 (2 ₂ ,..., 2 _m ), but the search method is not limited to this. For example, the cache server 2 that collects and manages the location of the designated program data of the content ID is determined in advance in association with the result (remainder) of the modulo operation of the content ID by a predetermined number N, and the designated program data The search request may be transmitted to the cache server 2 corresponding to the calculation result according to the modulo calculation result of the content ID.

The search result output unit 26c returns the search result output from the search execution unit 26b to the subject who requested the search. That is, when the search request receiving unit 26 a receives a search request from the data search / acquisition unit 25, the search result output unit 26 c outputs the search result to the data search / acquisition unit 25. In addition, when the search request receiving unit 26a receives a search request from another cache server 2 (2 ₂ ,..., 2 _m ), the search result output unit 26c receives the other via a communication transmitting / receiving unit (not shown). The search result is transmitted to the cache server 2 (2 ₂ ,..., 2 _m ).

The data request transmission / reception means 27 receives a data request from the content viewing apparatus 3 and transmits / receives a data request to / from another cache server 2 (2 ₂ ,..., 2 _m ). Here, the data request transmission / reception unit 27 includes a data request reception unit 27a and a data request unit 27b.

The data request accepting unit 27a accepts a request for blocked content (data request) from the content viewing apparatus 3 or another cache server 2 (2 ₂ ,..., 2 _m ) via a communication transmitting / receiving unit (not shown). Is. This data request includes information indicating whether the request is in accordance with the organization, and, if the request is not in organization, includes channel identification and broadcast time, which are information for specifying the blocked content. ing.
If the data request is a request in accordance with the composition, the data request receiving means 27a transmits the organized program data received by the data receiving means 20 to the requested content viewing apparatus 3 to the data transmitting means 28. Instruct to do so.

On the other hand, if the data request is not a request according to the organization, the data request accepting unit 27a specifies information (for example, IP) that specifies the content viewing device 3 or the cache server 2 (2 ₂ ,..., 2 _m ) that requested the data. And the channel identification and broadcast time included in the data request are output to the data search / acquisition means 25.
At this time, the data request accepting unit 27a instructs the data transmitting unit 28 to stop the organized program data to the requested content viewing device 3.

In response to a request from the data search / acquisition unit 25, the data request unit 27b sends to the other cache server 2 (2 ₂ ,..., 2 _m ) or the content distribution server 1 via a communication transmission / reception unit (not shown). The data request is transmitted.

The data transmission means 28 transmits the blocked content to the content viewing apparatus 3 and other cache servers 2 (2 ₂ ,..., 2 _m ) via communication transmission / reception means (not shown).
The data transmitting unit 28 transmits the blocked content (organized program data, designated program data) output from the data receiving unit 20 to the content viewing device 3. However, the data transmission unit 28 switches between the content viewing device 3 to transmit the organized program data or the designated program data according to an instruction from the data request receiving unit 27a.
Further, the data transmission unit 28 transmits the blocked content (designated program data) output from the data search / acquisition unit 25 to the other requested cache servers 2 (2 ₂ ,..., 2 _m ). .

By configuring the cache server 2 in this manner, the cache server 2 can distribute the content (blocked content) to the content viewing device 3 according to the organization information. Further, the cache server 2 can distribute the blocked content requested by the content viewing apparatus 3 without using the organization information. At this time, if the cache server 2 stores the blocked content (designated program data) requested from the content viewing device 3, it transmits it. If not, the cache server 2 transmits another cache server 2 (2 ₂ ,..., 2 _m ), the designated program data is acquired and transmitted to the content viewing apparatus 3. As a result, the cache server 2 can transmit data in response to a data request from the content viewing apparatus 3 without imposing a load on the content distribution server 1.
Note that the cache server 2 can operate the computer with a program (cache program) that causes the computer to function as each of the above-described means.

[Configuration of content viewing device]
Next, the configuration of the content viewing apparatus 3 will be described with reference to FIG. 6 (refer to FIG. 1 as appropriate). Here, in the content viewing device 3, a display device M for displaying the reproduced content is connected to the outside. In addition, the content viewing apparatus 3 includes a remote control device R for performing operations such as specifying a channel and specifying a past broadcast time in organization.

This remote control device R includes a button for designating a broadcast time in addition to a general remote control operation button such as a numeric button for designating a channel.
For example, a “one hour ago” button for designating a broadcast time one hour before the broadcast time currently being viewed, a “one day ago” button for designating a broadcast time one day ago, and the like.
Also, a button for advancing the broadcast time with respect to the broadcast time once specified in the past, for example, a “10 minutes later” button, a “30 minutes later” button, or to return to the current broadcast time. The “return” button or the like is provided.
Of course, these buttons are merely examples, and are not limited to the times indicated on the buttons. In addition to the “Return” button, the channel may be changed to return to the current broadcast time.

Hereinafter, the configuration of the content viewing apparatus 3 will be described in detail.
As shown in FIG. 6, the content viewing apparatus 3 includes a data receiving unit 30, a data reproducing unit 31, a data request receiving unit 32, and a data requesting unit 33.

The data receiving means 30 receives the organized program data and designated program data, which are blocked contents, from the cache server 2 via communication transmitting / receiving means (not shown). The data receiving means 30 receives a blocked content having a channel identification (see FIG. 4) corresponding to the channel by designating a channel from the external remote control device R, and is included in the blocked content. Only the data (block data) being output is output to the data reproducing means 31.
The data receiving means 30 stores the channel identification and broadcast time output to the data reproducing means 31 as block data for current reproduction in a storage medium such as a memory (not shown).

  The data reproducing means 31 inputs the block data sequentially output from the data receiving means 30 as stream data and reproduces it. For example, if the stream data is data encoded by the MPEG2 encoding method, the data reproducing means 31 uses an external display device as data such as video and audio in an output format that can be decoded and displayed by MPEG2. Output to M.

The data request accepting unit 32 accepts a request for content whose broadcast time has been changed from the remote control device R with respect to the current content broadcast time.
This data request accepting means 32 is notified by the remote control device R of pressing of a button for changing the broadcast time (for example, “one hour ago” button, etc.) by, for example, infrared communication, so that it does not depend on the composition. Accepts a data request instruction specifying a time. Further, the data request accepting unit 32 is notified of pressing of a button (for example, a “return” button) for ending the data request from the remote control device R, so that the end of the data request not depending on the organization, that is, An instruction to switch to data viewing according to the organization is received.
Then, the data request accepting unit 32 notifies the data requesting unit 33 of the fact that the instruction of the data request not based on the composition (or the end thereof) has been accepted and the designated broadcast time (1 hour ago etc.).

The data request unit 33 requests the cache server 2 for blocked content (organized program data, designated program data) via a communication transmitting / receiving unit (not shown).
That is, the data request means 33 sequentially requests the program data for the cache server 2 and designates to the cache server 2 when the data request accepting means 32 accepts the data request specifying the broadcast time. Switch to requesting program data. It should be noted that information indicating whether the request for organized program data or the request for designated program data is added to the data request.
When making a request for designated program data, the data request unit 33 calculates an actual broadcast time from the relative broadcast time notified from the data request reception unit 32, and the data reception unit 30 The data request including the channel (channel identification) received at is transmitted to the cache server 2.

Here, the data request unit 33 acquires the broadcast time of the data currently received from the data reception unit 30 and subtracts or adds the relative broadcast time notified from the data request reception unit 32. The broadcast time for actually making a data request is calculated.
In addition, the data requesting unit 33 performs the data request by sequentially shifting the broadcast time until the data request receiving unit 32 notifies the end of the data request. The time for shifting the broadcast time is a predetermined length of the blocked content.

By configuring the content viewing device 3 in this way, the content viewing device 3 caches the content data of the broadcast time specified along the composition time direction by the button operation of the remote control device R by the user. Requests can be made to the server 2. As a result, the user can view the content by changing the broadcast time of the content in the time direction for the channel currently being viewed, and can perform zapping in the time direction.
The content viewing apparatus 3 can operate the computer with a program (content viewing program) that causes the computer to function as each of the above-described means.

[Operation of content distribution system]
Next, the operation of the content distribution system according to the embodiment of the present invention will be described with reference to FIGS.

[Content delivery server operation]
First, the operation of the content distribution server 1 will be described with reference to FIG.

The content distribution server 1 refers to the organization information stored in the organization information storage unit 10 by the organization content reading unit 12a, and reads the content (organized content) according to the organization from the content storage unit 11 (step S1).
Then, the content distribution server 1 divides the content read in step S1 by the content dividing unit 12b into predetermined time intervals (step S2).

Then, the content distribution server 1 uses the composition information adding unit 12c to add the identification information (channel identification) for identifying the channel to the content data (block data) divided in step S2, the broadcast time on the composition, Is added to generate organized program data (blocked content) (step S3).
Thereafter, the content distribution server 1 distributes the organized program data (blocked content) generated in step S3 to a plurality of predetermined cache servers 2 via communication transmitting / receiving means (not shown) (step S4).
As a result, the content distribution server 1 can block the content according to the organization and distribute it to the cache server 2.

  Here, in the data request accepting means 13, when there is no request for blocked content (data request) not based on the organization information from the cache server 2 (No in step S5), the content distribution server 1 operates in step S1. return.

  On the other hand, if there is a data request in the data request receiving means 13 (Yes in step S5), the requested data is read from the content storage means 11 by the block data reading means 14a. That is, the block data reading unit 14a specifies the content corresponding to the channel identification and the broadcast time included in the data request from the organization information stored in the organization information storage unit 10, and from the content storage unit 11, Data corresponding to a predetermined time interval (block data) is read with the requested broadcast time data as the head data (step S6).

Then, the content distribution server 1 generates designated program data (blocked content) obtained by adding the channel identification and the broadcast time to the block data read in step S6 and blocking it by the organization information adding unit 14b (step S6). S7).
Then, the content distribution server 1 distributes the designated program data (blocked content) generated in step S7 to the cache server 2 that has requested the data via communication transmitting / receiving means (not shown) (step S8).
Thereby, the content distribution server 1 can distribute the requested content (blocked content) to the cache server 2 without depending on the program organization.

[Cache Server Operation]
Next, the operation of the cache server 2 will be described with reference to FIG. 8 (refer to FIG. 5 as appropriate for the configuration).
The cache server 2 waits for a request for blocked content (data request) in the data request accepting unit 27a (No in step S10). If there is a data request (Yes in step S10), the request is included in the organization information. It is determined whether the request is in accordance, that is, a request for organized program data (step S11).

  Here, when the data request is a request according to the organization information (Yes in step S11), the cache server 2 receives the organization program data from the content distribution server 1 by the data receiving means 20 (step S12), and the data The transmission program 28 transmits the organized program data to the requested content viewing apparatus 3 (step S13). Then, the cache server 2 returns the operation to step S10.

On the other hand, if the data request is not a request according to the organization information (No in step S11), the cache server 2 searches the designated program data by the data management means 26 in response to a request from the data search / acquisition means 25 ( Step S14).
At this time, the data management unit 26 receives a request from the data search / acquisition unit 25 by the search request reception unit 26a, and designates the requested channel identification and broadcast time as a search key by the search execution unit 26b. Search program data. When there is no designated program data corresponding to the own cache server 2 (2 ₁ ), the search execution means 26b transmits a search request to the other cache servers 2 (2 ₂ ,..., 2 _m ). The corresponding designated program data is searched.
Then, the search result is notified to the data search / acquisition means 25 via the search result output means 26c.

If the requested program data requested is present in the own cache server 2 (2 ₁ ) (Yes in step S15), the cache server 2 uses the data retrieval / acquisition means 25 via the data reading means 22. Then, the designated program data is read from the data storage means 23 (step S16).

On the other hand, if the requested program data requested is not present in the own cache server 2 (2 ₁ ) (No in step S15), it is present in the other cache server 2 (2 ₂ ,..., 2 _m ). If so (Yes in step S17), the cache server 2 makes a data request to the other cache server 2 (2 ₂ ,..., 2 _m ) by the data request unit 27b, and the data reception unit 20 The designated program data is acquired (step S18).

If the designated program data does not exist in the own cache server 2 (2 ₁ ) or the other cache server 2 (2 ₂ ,..., 2 _m ) (No in step S17), the cache server 2 Then, a data request is made to the content distribution server 1 by the data request means 27b, and the designated program data is acquired by the data receiving means 20 (step S19).
Then, the cache server 2 transmits the designated program data acquired in step S16, step S18, or step S19 to the content viewing device 3 by the data transmission unit 28 (step S20).

As a result, the cache server 2 receives the data request from the content viewing device 3, and even if the designated program data does not exist in the own cache server 2 (2 ₁ ), the other cache server 2 (2 ₂ ,..., 2 _m ) holds the designated program data, the data can be acquired and transmitted to the content viewing device 3, so that the load on the content distribution server 1 can be reduced.

[Operation of content viewing device]
Next, the operation of the content viewing apparatus 3 will be described with reference to FIG.
The content viewing device 3 requests the cache server 2 for organized program data (blocked content) corresponding to the organization of the currently selected channel by the data request means 33. Then, the content viewing apparatus 3 receives (acquires) the organized program data by the data receiving means 30 (step S30).
Thereafter, the content viewing apparatus 3 reproduces the organized program data received in step S30 by the data reproducing means 31 (step S31).

  Then, in the data request accepting unit 32, when there is no data request instruction specifying the broadcast time from the remote control device R operated by the user (No in step S32), the content viewing device 3 returns the operation to step S30.

On the other hand, when the data request accepting unit 32 receives a data request instruction specifying the broadcast time from the remote control device R operated by the user (Yes in step S32), the content viewing device 3 uses the data requesting unit 33 to The cache server 2 is requested for designated program data (blocked content) at the designated broadcast time of the currently selected channel. Then, the content viewing apparatus 3 receives (acquires) the designated program data by the data receiving means 30 (step S33).
Thereafter, the content viewing apparatus 3 reproduces the designated program data received in step S33 by the data reproducing means 31 (step S34).

  Here, in the data request receiving means 32, when there is a data request instruction specifying another broadcast time from the remote control device R operated by the user (Yes in step S35), the content viewing device 3 goes to step S33. Return action. As a result, the user can view the content at a different broadcast time while viewing the content at a broadcast time different from that of the current organization, and zapping in the time direction in the viewing channel. it can.

On the other hand, if there is no data request instruction specifying another broadcast time in the data request receiving means 32 (No in step S35), the content viewing apparatus 3 advances the operation to step S36.
Then, in the data request receiving means 32, when there is an instruction (return instruction) to switch from viewing the designated program data for which the broadcast time is designated to viewing the organized program data according to the composition (Yes in step S36), The content viewing apparatus 3 returns to step S30, and acquires and reproduces data according to the organization.

On the other hand, if there is no instruction to switch to viewing the organized program data according to the composition (No in step S36), the content viewing apparatus 3 returns to step S33 and sequentially acquires the designated program data from the designated broadcast time. And play back.
Accordingly, the content viewing device 3 reproduces content having different broadcast times or data having different times even for the same content according to an instruction from the user during reproduction of data (content) according to the organization. Can do.

S content distribution system 1 content distribution server 10 organization information storage means 11 content storage means 12 organization program data transmission means 12a organization content reading means 12b content division means 12c organization information addition means 13 data request acceptance means (first data request acceptance means )
14 Designated program data transmitting means 14a Block data reading means 14b Composition information adding means 2 Cache server 20 Data receiving means 21 Data writing means 22 Data reading means 23 Data storage means 24 Data erasing means 25 Data search / acquisition means 26 Data management means 26a Search request acceptance means 26b Search execution means 26c Search result output means 27 Data request transmission / reception means 27a Data request acceptance means (second data request acceptance means)
27b Data request means 28 Data transmission means 3 Content viewing device 30 Data reception means 31 Data reproduction means 32 Data request reception means 33 Data request means

Claims (6)

A content distribution server, a cache server, and a content viewing device are connected via a network, and content is distributed from the content distribution server to the content viewing device via the cache server in accordance with preset organization information. And a content distribution system for distributing content specified by the content viewing device,
The content distribution server is
Content storage means for storing a plurality of contents;
The content to be distributed according to the organization information is divided into block data having a predetermined time length, and a channel identification for identifying a broadcast channel in the organization of the content and a broadcast time in the organization of the block data are added. Organized program data transmission means for generating blocked content and transmitting it to the cache server as organized program data;
First data request accepting means for accepting a data request designating the channel identification and the broadcast time from the cache server;
Based on the organization information, the content data for the time length corresponding to the channel identification and broadcast time specified in the data request received by the first data request receiving means is read from the content storage means and A designated program data transmitting means for generating a blocked content to which channel identification and broadcast time are added, and transmitting the content as designated program data to a requested cache server,
The cache server is
Data storage means for temporarily storing each of the blocked contents;
Data receiving means for receiving the organized program data and the designated program data, which are blocked contents transmitted from the content distribution server, and storing them in the data storage means;
Second data request accepting means for accepting, from the content viewing device, a data request for the designated program data according to organization or the designated program data designating the channel identification and the broadcast time;
When the data request received by the second data request receiving means requests the designated program data by specifying the channel identification and the broadcasting time, the data is received using the channel identification and the broadcasting time as a search key. Search execution means for searching for designated program data from storage means;
A data requesting unit for requesting the designated program data from the content distribution server by designating channel identification and broadcast time as the search key when the requested designated program data is not retrieved in the retrieval execution unit; ,
Data transmission means for transmitting the designated program data searched by the search execution means, or the organized program data or the designated program data received by the data receiving means, to the content viewing device that requested the data;
A content distribution system comprising: A plurality of the cache servers are connected to the network,
The search execution means searches for specified program data corresponding to the search key with another cache server, and the second data request accepting means further receives the specified program data from the other cache server. Accepts requests for data,
In the search execution means, if the designated program data corresponding to the search key is not stored in the data storage means and is stored in the other cache server, the data requesting means The content distribution system according to claim 1, wherein program data is requested from the other cache server. A content distribution server, a cache server, and a content viewing device are connected via a network, and content is distributed from the content distribution server to the content viewing device via the cache server in accordance with preset organization information. And the content distribution server in a content distribution system for distributing content specified by the content viewing device,
Content storage means for storing a plurality of contents;
The content to be distributed according to the organization information is divided into block data having a predetermined time length, and a channel identification for identifying a broadcast channel in the organization of the content and a broadcast time in the organization of the block data are added. Organized program data transmission means for generating blocked content and transmitting it to the cache server as organized program data;
Data request accepting means for accepting a data request designating the channel identification and the broadcast time from the cache server;
Based on the organization information, content data corresponding to the time length corresponding to the channel identification and broadcast time specified in the data request received by the data request receiving means is read from the content storage means, and the channel identification and A designated program data transmitting means for generating blocked content to which the broadcast time is added and transmitting the requested content to the requested cache server as designated program data;
Content delivery server, wherein a call with a. A content distribution server comprising a content storage means for storing a plurality of contents, a cache server, and a content viewing apparatus are connected via a network, and the cache server is connected to the cache server according to preset organization information. A computer of the content distribution server in a content distribution system that distributes content to the content viewing device via the network and distributes content specified from the content viewing device;
The content to be distributed according to the organization information is divided into block data having a predetermined time length, and a channel identification for identifying a broadcast channel in the organization of the content and a broadcast time in the organization of the block data are added. Organized program data transmitting means for generating blocked content and transmitting it to the cache server as organized program data,
Data request accepting means for accepting a data request designating the channel identification and the broadcast time from the cache server;
Based on the organization information, content data corresponding to the time length corresponding to the channel identification and broadcast time specified in the data request received by the data request receiving means is read from the content storage means, and the channel identification and A designated program data transmitting means for generating block-formed content with an added broadcast time and transmitting the content as designated program data to a requested cache server;
Content delivery program which is characterized a call to function as. A content distribution server, a cache server, and a content viewing device are connected via a network, and content is distributed from the content distribution server to the content viewing device via the cache server in accordance with preset organization information. And the cache server in the content distribution system for distributing the content specified from the content viewing device,
Blocked content in which content is divided into block data having a predetermined time length and channel identification for identifying the broadcast channel in the organization of the content and the broadcast time in the organization of the block data are added temporarily. Data storage means for storing automatically,
Data receiving means for receiving the blocked content transmitted from the content distribution server and storing it in the data storage means;
Data request accepting means for accepting a data request from the content viewing device for organized program data that is blocked content according to organization or designated program data that is the blocked content designating the channel identification and the broadcast time;
In the data request received by the data request receiving means, when the designated program data is requested by designating the channel identification and the broadcasting time, the data storage means, using the channel identification and the broadcasting time as a search key, And search execution means for searching for designated program data corresponding to the search key with another cache server connected to the network,
A data requesting unit for requesting the designated program data from the content distribution server by designating channel identification and broadcast time as the search key when the requested designated program data is not retrieved in the retrieval execution unit; ,
Data transmission means for transmitting the designated program data searched by the search execution means, or the organized program data or the designated program data received by the data receiving means, to the content viewing device that requested the data;
A cache server comprising: A content distribution server, a cache server having data storage means for temporarily storing content, and a content viewing apparatus are connected via a network, and according to preset organization information, the content distribution server A computer of the cache server in a content distribution system that distributes content to the content viewing device via a cache server and distributes content specified from the content viewing device.
Blocked content in which content is divided into block data having a predetermined length of time and channel identification for identifying a broadcast channel in organization of the content and broadcast time in organization of the block data are added, Data receiving means received from the content distribution server and stored in the data storage means;
Data request accepting means for accepting a data request of the organized program data that is the blocked content according to the organization or the designated program data that is the blocked content designating the channel identification and the broadcast time from the content viewing device;
In the data request received by the data request receiving means, when the designated program data is requested by designating the channel identification and the broadcasting time, the data storage means, using the channel identification and the broadcasting time as a search key, And search execution means for searching for specified program data corresponding to the search key with another cache server connected to the network,
In the search execution means, when the requested designated program data is not found, the data request means for designating the channel identification and the broadcast time as the search keys and requesting the designated program data from the content distribution server,
Data transmission means for transmitting the designated program data searched by the search execution means, or the organized program data or the designated program data received by the data receiving means, to the content viewing apparatus that requested the data;
A cache program characterized by functioning as

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