JP2010237851A - Content distribution/storage system, related content acquisition method, node device, and node processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a node device capable of highly efficiently finding out the location of content data without increasing the number of records to be registered in content catalog information as possible. <P>SOLUTION: A node device in a content distribution/storage system, in which a plurality of content data are distributed and stored in a plurality of node devices capable of communicating through a network, is provided with: a retrieval information acquisition means for acquiring reference content retrieval information for retrieving the location of reference content data as a reference in a plurality of content data and relation information showing a relation between the reference content data and related content data related with the reference content data; a relation retrieval information generation means for generating related content retrieval information from the reference content retrieval information and the related information; and a related content acquisition means for retrieving the location of the related content data, and for acquiring the related content data based on the related content retrieval information generated by the relation retrieval information generation means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technical field of a peer-to-peer (P2P) type communication system including a plurality of node devices that can communicate with each other via a network.

  In this type of peer-to-peer communication system, there is known a content distribution storage system in which content data is distributed and stored in a plurality of node devices. As a result, a server that is a drawback of a client-server communication system is known. Server load due to access concentration can be reduced.

  The location of the content data thus distributed and stored is determined by using a distributed hash table (hereinafter referred to as DHT (Distributed Hash Table) as disclosed in Patent Document 1, for example) and a unique content ID for each content. It is possible to search efficiently by the query including as a key. Also, the content catalog information used for the search is distributed to all the node devices in the content distributed storage system by, for example, multicast. In the content catalog information, content attribute information such as a content ID, a content name, a publication start date / time, a publication end date / time, and a keyword are registered for each piece of content data that can be used in the distributed content storage system.

JP 2008-129694 A

  By the way, as the types of content data registered in the content catalog information increase, the data amount of the content catalog information also increases. For example, even if the content data has the same content, a content ID is assigned as a different content if the bit rate is different. Then, content attribute information including the content ID is registered as one record in the content catalog information.

  As the data amount of the content catalog information increases, the communication load for communicating the content catalog information through the network increases.

  The present invention has been made in view of the above points and the like, and is a distributed content storage that can discover the location of content data more efficiently without increasing the number of records to be registered in the content catalog information as much as possible. It is an object to provide a system, a related content acquisition method, a node device, and a node processing program.

  In order to solve the above problem, the invention according to claim 1 is the node device in the content distributed storage system in which a plurality of content data is distributed and stored in a plurality of node devices that can communicate with each other via a network. The reference content search information for searching for the location of reference content data serving as a reference in the plurality of content data, and the relationship between the reference content data and at least one related content data related thereto Search information acquisition means for acquiring related information to be shown, related search information generation means for generating related content search information from the reference content search information and the related information, and the related content generated by the related search information generation means Based on the search information, the location of the related content data is searched and Characterized in that it comprises a related content acquisition means for acquiring communication content data.

  According to a second aspect of the present invention, there is provided the node device according to the first aspect, wherein the content attribute information of the reference content data and including the reference content search information of the reference content data is described. Search information storage means for storing information is further provided, wherein the related search information generation means generates the related content search information from the reference content search information and the related information stored in the search information storage means. Features.

  According to a third aspect of the present invention, in the node device according to the first or second aspect, the reference information, wherein the search information acquisition means is identification data (for example, content ID) unique to the reference content data Search information in which search information and the related information are associated with each other is acquired, and the related search information generation unit hashes data including the reference content search information and the related information with a predetermined hash function. To generate the related content search information.

  The invention according to claim 4 is the node device according to claim 3, wherein the reference content search information is identification data unique to the reference content data, and the related content search information is specific to the related content data. It is identification data, and the related search information generation means generates the identification data of the related content data by adding or subtracting a predetermined value to a numerical value represented by the identification data of the reference content data. It is characterized by that.

  According to a fifth aspect of the present invention, in the node device according to the fourth aspect, the related search information generating means includes information (in the number indicated by the identification data of the reference content data) in the related information ( For example, the identification data of the related content data is generated by adding or subtracting a numerical value corresponding to the number of stories).

  According to a sixth aspect of the present invention, in the node device according to any one of the first to fifth aspects, the search information acquisition means includes the reference content search information and a keyword representing the related information as the related information. Is obtained, and the related search information generating means generates related content search information from the reference content search information and the keyword.

  According to a seventh aspect of the present invention, in the node device according to the sixth aspect, the search information acquisition unit is configured to search for search information in which the reference content search information is associated with the keyword as the related information. When the selection information is specified by the user via the input means and the display means for acquiring and displaying the selection information corresponding to the information indicated by the keyword, the related search information generation means The related content search information is generated from the keyword corresponding to selection information and the reference content search information, and the related content acquisition means is based on the related content search information generated by the related search information generation means, The related content data is acquired.

  The invention of a node processing program according to an eighth aspect is characterized in that it functions as the node device according to any one of the first to seventh aspects.

  The invention according to claim 9 is a distributed content storage system in which a plurality of content data is distributed and stored in a plurality of node devices that can communicate with each other via a network. Search information acquisition for acquiring reference content search information for searching for the location of reference content data serving as a reference for and reference information indicating the relationship between the reference content data and at least one or more related content data related thereto Means for generating related content search information from the reference content search information and the related information, and the related content based on the related content search information generated by the related search information generating means. Search the location of the data and obtain the related content data Characterized in that it comprises a communication content acquiring means.

  The invention according to claim 10 is a distributed content storage system in which a plurality of content data is distributed and stored in a plurality of node devices that can communicate with each other via a network. Request information transmission for transmitting request information indicating a request for reference content search information for searching for the location of at least one related content data related to reference content data serving as a reference to another node device or server device The other node device or the server device according to the request information received by the request information receiving unit and the request information receiving unit that receives the request information transmitted from the one node device. , Reference content search information for searching for the location of the reference content data, and the reference content Search information acquisition means for acquiring relation information indicating the relation between content data and related content data related thereto, and related search information generation means for generating related content search information from the reference content search information and the related information Related content search information transmitting means for transmitting the related content search information generated by the related search information generating means to the one node device, wherein the one node device is the other node device or The related content search information receiving means for receiving the related content search information transmitted from the server device, and the location of the related content data based on the related content search information received by the related content search information receiving means. Search related content and retrieve related content data Characterized in that it comprises a stage, a.

  The invention according to claim 11 is a related content acquisition method in a content distributed storage system in which a plurality of content data is distributed and stored in a plurality of node devices that can communicate with each other via a network, , Reference content search information for searching for the location of reference content data serving as a reference in the plurality of content data, and association indicating the relationship between the reference content data and at least one related content data related thereto Obtaining the information; the node device generating related content search information from the reference content search information and the related information; and the node device based on the generated related content search information. The location of the related content data is searched and the related content data is searched. Characterized in that it comprises a step of acquiring, a.

  According to the first, eighth, ninth, tenth, or eleventh aspect of the present invention, the related content is obtained from the reference content search information of the reference content data and the related information indicating the relationship between the reference content data and the related content data. Since the search information is generated, the location of the related content data is searched based on the related content search information, and the related content data is acquired, the related content of the related content data is included in the content catalog information as the search information. There is no need to register search information. Therefore, an increase in the number of records to be registered in the content catalog information can be prevented, and the location of the content data can be found more efficiently.

  According to the second aspect of the present invention, the amount of data of the content catalog information stored in the node device can be reduced. Therefore, in the node device, the time for acquiring the content catalog information through the network, the content catalog information The storage capacity of the hard disk or the like necessary for storing the content, the time for reading the content catalog information from the hard disk into the RAM, the time for searching the content search information of the desired content data from the content catalog information, for example, with keywords, etc., increase. Can be solved.

  According to the invention described in claim 3, the node device is configured to generate the related content search information by hashing the data including the reference content search information of the reference content data and the related information with a hash function. Therefore, related content search information that does not overlap with content search information of other content data can be generated more efficiently and easily.

  According to the invention described in claim 4 or 5, the node device generates identification data of related content data by adding or subtracting a predetermined value to a numerical value represented by the identification data of the reference content data. Since it comprised in this way, the related content search information which does not overlap with the content search information of other content data can be produced | generated more efficiently and easily.

  According to the invention described in claim 6, in addition to the reference content search information, the node device can quickly acquire a keyword representing the related information from the content catalog information, and can immediately generate the related content.

  According to the seventh aspect of the present invention, since the relationship between the reference content data and the related content data is presented to the user by the keyword representing the related information, the user can easily specify the related content data. Can do.

It is a figure which shows an example of the connection aspect of each node apparatus in the content distributed storage system which concerns on this embodiment. It is a figure which shows an example of the information registered into content catalog information. It is a figure which shows the example of an outline structure of the node Nn. It is a figure which shows an example of the information described in the content catalog information which has a special keyword in the record of content attribute information. It is a flowchart which shows the process at the time of content input of a content provision server. It is a flowchart which shows the process at the time of the content search in the control part 11 of the node Nn. 4 is a flowchart illustrating processing when content is input by the content providing server according to the first exemplary embodiment. 6 is a flowchart illustrating processing at the time of content search in a control unit 11 of a node Nn according to the first exemplary embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the invention will be described with reference to the drawings. The embodiment described below is an embodiment when the present invention is applied to a content distributed storage system.

[ 1. Outline and configuration of distributed content storage system ]
First, with reference to FIG. 1 etc., the structure and operation | movement outline | summary of the content distribution preservation | save system which concern on this embodiment are demonstrated.

  FIG. 1 is a diagram showing an example of a connection mode of each node device in the distributed content storage system according to this embodiment.

  As shown in the lower frame 101 of FIG. 1, IX (Internet eXchange) 3, ISP (Internet Service Provider) 4a, 4b, DSL (Digital Subscriber Line) line operators (devices) 5a, 5b, FTTH (Fiber To A network (real-world communication network) 8 such as the Internet is constructed by a line provider (device) 6 and a communication line (for example, a telephone line or an optical cable) 7. Note that a router for transferring data (packets) is appropriately inserted into the network 8 in the example of FIG.

  A plurality of node devices (hereinafter referred to as “nodes”) Nn (n = 1, 2, 3,...) Are connected to such a network 8. Each node Nn is assigned a unique manufacturing number and an IP (Internet Protocol) address. The content distributed storage system S according to the present embodiment is a peer-to-peer network system formed by participation of any of a plurality of nodes Nn, as shown in the upper frame 100 of FIG. It has become.

  A network 9 shown in the upper frame 100 of FIG. 1 is an overlay network 9 (logical network) that forms a virtual link formed using the existing network 8. Such an overlay network 9 is realized by a specific algorithm, for example, an algorithm using DHT. Each node Nn participating in the content distributed storage system S (in other words, the overlay network 9) is assigned a node ID, which is unique identification data having a predetermined number of digits. The node ID is, for example, a value (for example, the bit length is 160 bits) obtained by hashing an IP address or a manufacturing number individually assigned to each node Nn with a common hash function (for example, SHA-1). is there. The node IDs are arranged in a distributed manner in the ID space.

  Each node Nn holds a routing table using DHT. This routing table defines the transfer destinations of various messages on the content distributed storage system S. Specifically, a plurality of pieces of node information including a node ID, an IP address, and a port number of a node Nn that are moderately separated in the ID space are registered in the routing table.

  Such a routing table using DHT is well known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and will not be described in detail.

  Further, in the content distributed storage system S, various content data (for example, movies, music, etc.) having different contents are distributed (stored) in a plurality of nodes Nn in a predetermined file format. In addition, information such as a content name (title) and a content ID (identification data unique to each content) is assigned to these content data (hereinafter simply referred to as “content”). This content ID is search information for searching for the location of the content. For example, the content name + an arbitrary numerical value (or may be the first few bytes of content data) is generated by hashing with the same hash function as when obtaining the node ID (in the same ID space as the node ID) Placement). Alternatively, the system administrator may give a unique ID value (same bit length as the node ID) for each content.

  The index information includes the location of the content that is distributed and stored in this way, that is, a set of node information of the node Nn that stores the content (hereinafter referred to as “content holding node”) and the content ID of the content. Information. The index information is stored (stored in an index cache) and managed by a node Nn (hereinafter referred to as “root node”) that manages the location of the content. Such a root node is determined to be, for example, the node Nn having the node ID closest to the content ID (for example, the higher-order digits match more).

  When a user of a certain node Nn wants to acquire desired content, the node Nn (hereinafter referred to as “user node”) generates a content location inquiry (search) message (query). The content location inquiry message includes the content ID of the content selected by the user and its own IP address. The content location inquiry message is sent to another node Nn according to the routing table using the DHT stored in the user node. That is, the user node sends a content location inquiry message toward the root node (to the root node). As a result, the content location inquiry message finally arrives at the root node by DHT routing using the content ID as a key. The DHT routing is known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and thus detailed description thereof is omitted.

  When the root node receives the content location inquiry message, the root node obtains index information corresponding to the content ID included therein from the index cache. Then, the root node returns the index information to the user node that is the transmission source of the received content location inquiry message. When the user node acquires the index information by the above-described method, the user node accesses the content holding node based on the IP address of the content holding node included in the index information. Therefore, the user node can download (acquire) and play back the content. The root node transmits a content transmission request message to the content holding node indicated by the IP address or the like included in the index information. In addition, the content holding node can access the user node and provide the content.

  In this way, the user node transmits a content location inquiry message including the content ID to another node Nn. By the message, the location of the content, that is, the content holding node where the content is stored is searched. The user node can acquire content from the content holding node.

  Further, content catalog information (an example of search information) is distributed from the content providing server to all the nodes Nn by multicast. The content catalog information registers (describes) a content ID used for content search.

  FIG. 2 is a diagram illustrating an example of registration of content catalog information. As shown in FIG. 2, in the content catalog information, a record of content attribute information including a content ID, a content name, a publication start date / time, a publication end date / time, and a keyword is registered for each content. Here, the keyword is used for the user to search for the content ID of the desired content from the content catalog information. For example, the keyword is a content genre or the like. When the user inputs a desired keyword, the content ID of the desired content is retrieved from the content catalog information. However, the content ID cannot be searched from the content catalog information before the publication start date and time and after the publication end date and time. Therefore, during this period, in the content distributed storage system S, the location of the content cannot be searched (cannot be acquired) using the content ID.

  By the way, among the many contents stored in the content distributed storage system S, there are contents related to each other. For example, the related content is content of the same content with different bit rates or content of the same title with continuous content (for example, episodes 1 to 24). Thus, the content IDs associated with each other have different content IDs.

  In the present embodiment, any one of a plurality of related contents is set as a reference content. One or more contents related to the reference content are set as related contents. For example, a standard bit rate content when the same content is distributed at a plurality of bit rates is the reference content. In addition, the content of the first episode when the contents of the first title to the second episode are distributed as the reference content. On the other hand, content that differs in bit rate from the reference content, content other than the first episode, and the like are related content. In other words, the related content is similar content accompanying the reference content. Such association is performed by, for example, a content provider (for example, a distribution vendor).

  In the present embodiment, only the content attribute information record of the reference content is registered in the content catalog information. In the keyword search, only the content ID of the reference content (hereinafter referred to as “reference content ID” (an example of reference content search information)) can be found from the content catalog information. The content ID of the related content (hereinafter referred to as “related content ID” (an example of related content search information)) is generated based on the reference content ID according to the content ID generation (conversion) rule.

[ 2. Configuration and function of node Nn ]
Next, the configuration and function of the node Nn will be described with reference to FIG.

  FIG. 3 is a diagram illustrating a schematic configuration example of the node Nn.

  As shown in FIG. 3, each node Nn includes a control unit 11, a storage unit 12, a buffer memory 13, a decoder unit 14, a video processing unit 15, a display unit 16 (an example of display means), an audio process, and the like. A unit 17, a speaker 18, a communication unit 19, and an input unit 20 are provided. The control unit 11, the storage unit 12, the buffer memory 13, the decoder unit 14, the communication unit 19, and the input unit 20 are connected to each other via a bus 21. The control unit 11 includes a CPU having a calculation function, a working RAM, a ROM that stores various data and programs, and the like. The storage unit 12 includes a hard disk or the like for storing and saving various data and various programs. The buffer memory 13 temporarily stores received content and the like. The decoder unit 14 decodes the encoded video data (video information), audio data (audio information), and the like included in the content (data expansion, decoding, etc.). The video processing unit 15 performs a predetermined drawing process on the decoded video data or the like and outputs it as a video signal. The display unit 16 is a CRT, a liquid crystal display, or the like that displays video based on the video signal output from the video processing unit 15. The sound processing unit 17 performs D (Digital) / A (Analog) conversion of the decoded audio data into an analog audio signal, and then amplifies the signal by an amplifier and outputs the amplified signal. The communication unit 19 controls communication of information between the speaker 18 that outputs the audio signal output from the audio processing unit 17 as a sound wave, and other nodes Nn and the content providing server through the network 8. The input unit 20 is an input unit that receives an instruction from a user and gives an instruction signal corresponding to the instruction to the control unit 11. The input unit 20 is, for example, a keyboard, a mouse, or an operation panel. As the node Nn, a personal computer, an STB (Set Top Box), a TV receiver, or the like is applicable.

  The storage unit 12 (an example of search information storage means) stores a node processing program of the present invention, a content file, content catalog information, index information, a routing table using DHT, and the like. The node processing program may be downloaded from a predetermined server on the network 8, for example. For example, it may be recorded on a recording medium such as a CD-ROM and read through a drive of the recording medium.

  In the above configuration, the control unit 11 performs overall control by the CPU reading and executing a program stored in the storage unit 12 or the like. When the node Nn participates in the content distributed storage system S and the program is executed, processing as at least one of the above-described user node, root node, content holding node, and the like is performed.

  Furthermore, the control unit 11 functions as search information acquisition means, related search information generation means, related content acquisition means, and the like in the present invention.

  More specifically, the control unit 11 performs a keyword search using a keyword input or selected from the user through the input unit 20. The control unit 11 acquires the reference content ID including the keyword in the content attribute information from the content catalog information. And the control part 11 produces | generates related content ID according to a content ID production | generation rule from acquired reference | standard content ID and the relevant information mentioned later.

  Here, the content attribute information of the related content is not registered in the content catalog information. Therefore, as it is, the control unit 11 cannot know the existence of the related content. Therefore, a special keyword representing related information indicating the relationship between the reference content and the related content is registered in the content catalog information. Specifically, the special keyword is registered in the content attribute information record of each reference content in the content catalog information. In other words, the related information is information indicating what kind of related content exists in the reference content.

  FIG. 4 is a diagram illustrating an example of information described in content catalog information having a special keyword in a record of content attribute information. As shown in FIG. 4, the special keywords of the reference content whose content name is “AAA” are a bit rate of 2 Mbps and a bit rate of 4 Mbps. The special keyword is registered in the content attribute information record. The special keyword indicates that there is related content with a bit rate of 2 Mbps and related content with a bit rate of 4 Mbps with respect to reference content with a bit rate of 1 Mbps. In addition, the special keyword whose content name is “BBB” is the 2nd to 24th episodes with respect to the reference content of the 1st episode. The special keyword is registered in the record of the content attribute information of the reference content. The special keyword indicates that there is content related to the second story to the 24th story with respect to the reference content of the first story. Note that the bit rate of the reference content may be included in the content attribute information other than the special keyword.

  Originally, the keyword is used for the search, but the special keyword is not used for the search, and is interpreted internally by the control unit 11 in the program. Thus, for example, when the reference content ID is acquired, the control unit 11 can cause the user to select any bit rate (or story) based on the special keyword. As described above, if the special keyword is registered in the content catalog information, it is possible to cope with the case where the number of related contents and the related information are different for each content. If the reference start date and the release end date and time of the related content are different from each other, the control unit 11 can use the special keyword to include the start date and end date of the related content. Whether or not related content can be acquired can also be determined.

  Next, various content ID generation rules for obtaining related content IDs are conceivable. Two examples are given below.

(1) When Using Hash Function In this case, the control unit 11 generates a related content ID from data including a reference content ID and conversion condition data prepared in advance. The related content ID is generated by hashing with a hash function common to the node ID. The hash function generates a related content ID from the reference content ID and the conversion condition data. The conversion condition data may be, for example, data indicated by a special keyword (for example, 2 Mbps or the second episode).

(2) When content ID is a serial number In this case, the control unit 11 generates a related content ID by adding or subtracting a predetermined value to a numerical value represented by the reference content ID. For example, in the case of content that continues from episode 1 to episode 24, the related content ID is generated by adding a numerical value corresponding to the number of stories of the related content to the numerical value represented by the reference content ID. The number of related content talks is indicated by a special keyword. Therefore, the related content ID is generated as a serial number from the reference content ID. In addition, even if it is not a serial number, there is no problem if every other rule or every 100th rule is determined.

  When the related content ID is generated according to the special keyword as described above, the control unit 11 transmits a content location inquiry message including the related content ID to another node Nn. The content location inquiry message is transmitted through the network 8 according to a routing table using DHT. The control unit 11 searches for the location of the related content through DHT routing and acquires the related content. In this way, it is possible to provide content of different formats without increasing the content catalog information.

[ 3. Operation of Content Distributed Storage System S ]
Next, the operation of the distributed content storage system S will be described.

  First, the basic operation of the content distribution storage system S will be described with reference to FIGS.

  FIG. 5 is a flowchart showing processing at the time of content input by the content providing server. FIG. 6 is a flowchart showing processing at the time of content search in the control unit 11 of the node Nn.

  The process shown in FIG. 5 is started when, for example, a content input instruction is issued by a system administrator. Processing of the content providing server described later is executed by a CPU of the content providing server (not shown). When the process is started, the content providing server reads content information to be input from, for example, an external device in accordance with the content input instruction (step S1). The information to be read is information indicating the reference content and related content related thereto, and the content name, release start date / time, and release end date / time of each content.

  Next, the content providing server assigns a reference content ID to the reference content (step S2). The reference content ID thus assigned is stored in a predetermined area for reference content in the RAM.

  Next, the content providing server generates a related content ID of the related content from the reference content ID and the related information according to the above-described content ID generation rule, and assigns the generated related content ID to the related content (step) S3). The related information indicates a relationship with related content related to the reference content. When there are a plurality of related contents related to the reference content, a unique related content ID is generated and assigned to each.

  Next, the content providing server determines whether or not the related content ID assigned in step S3 overlaps with the content ID registered in the assigned ID list (step S4). If they are overlapping (step S4: YES), the process proceeds to step S5. If they are not overlapping (step S4: NO), the process proceeds to step S6. Note that the content IDs of all the contents that have been input in the system S are registered in the assigned ID list. In addition, when there are a plurality of related contents related to the reference content, duplication determination of each related content ID is performed.

  In step S5, the content providing server reassigns another reference content ID to the reference content, moves to step S3, and performs the same processing as described above.

  On the other hand, in step S6, the reference content ID assigned in step S2 and the related content ID assigned in step S3 are registered in the assigned ID list.

  Next, the content providing server selects a node Nn as a reference content input destination (storage destination). The content providing server selects, for example, at random from the node list, and transmits a content input request message to the selected node Nn. The content providing server transmits the reference content and stores the reference content (step S7). Note that node information of all or some of the nodes Nn participating in the system S is registered in the node list.

  Next, the content providing server selects a node Nn as a related content input destination (storage destination). The content providing server selects, for example, at random from the node list, and transmits a content input request message to the selected node Nn. The content providing server transmits the related content and stores the related content (step S8). Note that when there are a plurality of related contents, the node Nn to which each related content is input is selected, and each related content is stored in each node Nn.

  Next, the content providing server additionally registers content attribute information including the reference content ID, the content name, the publication start date and time, and the publication end date and time assigned to the reference content in the content catalog information (step S9).

  Next, the content providing server distributes the content catalog information to all the nodes Nn participating in the content distributed storage system S by, for example, DHT multicast (step S10). The distributed content catalog information is catalog information having a record of the additionally registered content attribute information. After the catalog information is distributed, the process is terminated. The content catalog information may be configured to be distributed to all the nodes Nn, for example, every predetermined period.

  Next, when the user inputs a desired keyword from the input unit 20 at the user node, the processing shown in FIG. 6 is started. Alternatively, when a content list in which a keyword (content name may be one of keywords) is described is displayed on the display unit 16 and the user selects a desired keyword from the displayed content list using the input unit 20, The process shown in FIG. 6 is started. When the process is started, the control unit 11 of the user node performs a keyword search using a keyword input or selected by the user (step S11). The keyword search is a search for the above-described keyword from the content catalog information. The content catalog information is stored in the storage unit 12.

  Next, the control unit 11 determines whether or not the content attribute information including the keyword is found by the keyword search (step S12). That is, it is determined whether the record of the content attribute information of the reference content has been found. If found (step S12: YES), the process proceeds to step S13. If not found (step S12: NO), the process ends.

  In step S13, the control unit 11 selects any one of the reference content corresponding to the found content attribute information and the related content. Such selection may be performed automatically or according to a selection instruction from the user.

  When the reference content is selected (step S13: reference content), the control unit 11 proceeds to step S14. When the related content is selected (step S13: related content), the control unit 11 proceeds to step S15. When there are a plurality of related contents, one or a plurality of related contents are selected.

  In step S14, the control unit 11 acquires a reference content ID from the content attribute information found in step S12.

  On the other hand, in step S15, the reference content ID is acquired from the content attribute information found in step S12. And the control part 11 acquires the relevant information corresponding to this reference | standard content ID.

  Next, the control unit 11 generates a related content ID from the acquired reference content ID and the acquired related information according to the content ID generation rule (step S16). When a plurality of related contents are selected, a related content ID of each related content is generated.

  Next, the control unit 11 searches the location of the reference content or related content by DHT routing based on the reference content ID acquired in step S14 or the related content ID generated in step S16. The control unit 11 acquires (downloads) the retrieved reference content or related content (step S17), and ends the process.

  As described above, according to the above embodiment, the node Nn as the user node is related content according to the content ID generation rule from the reference content ID of the reference content and the related information indicating the relationship between the reference content and the related content. ID is generated. The node Nn as the user node is configured to search for the location of the related content based on the related content ID and acquire the related content. As a result, it is not necessary to register the related content ID of the related content in the content catalog information. Therefore, it is possible to prevent an increase in the number of content records to be registered in the content catalog information, and to more efficiently find the location of the content. In addition, the search efficiency in the system S is improved (with the same keyword). The number of hits is reduced and the network load is reduced).

  Further, by preventing an increase in the number of content records registered in the content catalog information, the data size of the content catalog information can be reduced. As a result, the data amount of the content catalog information stored in each node Nn can be reduced. As a result, it is possible to solve the problem that the time for acquiring the content catalog information through the network 8 increases in the node Nn. In addition, the problem that the storage capacity of a hard disk or the like in the storage unit 12 necessary for storing the content catalog information can be solved. It is possible to solve the problem that the time for reading the content catalog information from the hard disk or the like to the RAM increases. Furthermore, it is possible to solve the problem that the time for searching the content ID or the like of the desired reference content from the content catalog information by using, for example, a keyword increases.

  In particular, when an electronic signature is added to each record in the content catalog information so that tampering can be checked, it is very effective to prevent an increase in the number of records because the data amount of each record is large.

Example 1
Next, with reference to FIG. 7 and FIG. 8, Embodiment 1 of the operation of the distributed content storage system S will be described. The processing shown in FIG. 5 and FIG. 6 shows the basic processing of the present embodiment. In Example 1, processing that makes the basic processing more specific will be described. Specifically, the process of generating the related content ID in step S3 shown in FIG. 5 is the process of generating the related content ID using a hash function in step S23 shown in FIG. That is, the content ID generation rule is defined as “the hash value obtained by adding a special keyword to the reference content ID and applying the hash function is used as the related content ID”. In the first embodiment, the process of selecting either the reference content or the related content in step S13 shown in FIG. 6 is the process of selecting either the reference content or the related content by the user in step S45 shown in FIG. did.

  FIG. 7 is a flowchart illustrating processing when content is input by the content providing server according to the first embodiment. FIG. 8 is a flowchart illustrating processing at the time of content search in the control unit 11 of the node Nn according to the first embodiment. Processing of the content providing server described later is executed by a CPU of the content providing server (not shown).

  The process shown in FIG. 7 is started under the same conditions as the process shown in FIG. In accordance with the content input instruction, the content providing server reads the reference content to be input and the related content from, for example, an external device (step S21). The content providing server also reads information indicating the content name, the publication start date and time, and the publication end date and time of each content from the external device. The related content is one or a plurality of contents having the same contents as the reference contents but different bit rates. Next, the content providing server assigns a reference content ID to the reference content (step S22). The reference content ID is given by, for example, a content name + an arbitrary numerical value generated by the hash function, or selected from a list of unassigned IDs to which a plurality of content IDs that have not yet been assigned are assigned. . The reference content ID thus assigned is stored in a predetermined area for reference content in the RAM.

  Next, the content providing server generates the related content ID by applying the data including the reference content ID and the bit rate of the related content to the hash function. The generated related content ID is given to the related content (step S23). When there are a plurality of related contents related to the reference content, a unique related content ID is generated and assigned to each.

  Note that the processing of steps S24 to S26 is the same as the processing of steps S4 to S6 shown in FIG.

  Next, in step S27, the content providing server adds the reference content and the bit rate of the related content as special keywords to the content attribute information of the reference content. In addition, when there are a plurality of related contents of the reference contents, each bit rate is added as a special keyword.

  The processes in steps S28 and S29 are the same as the processes in steps S7 and S8 shown in FIG.

  Next, in step S30, the content providing server additionally registers only the content attribute information of the reference content in the content catalog information. The additionally registered content catalog information includes a reference content ID given to the reference content ID, a content name, a release start date / time, a release end date / time, and a special keyword.

  The process in step S31 is the same as the process in step S10 shown in FIG.

  Next, the process shown in FIG. 8 is started in the user node under the same conditions as the process shown in FIG.

  Note that the processing in steps S41 and S42 is the same as the processing in steps S11 and S12 shown in FIG.

  Next, in step S43, the control unit 11 of the user node extracts a special keyword from the content attribute information of the found reference content.

  Next, the control unit 11 displays selection information corresponding to each bit rate indicated by the extracted special keyword on the display unit 16 (step S44), and prompts the user to select. For example, the display unit 16 displays three selection information (for example, selection buttons) “1 Mbps”, “2 Mbps”, and “4 Mbps”.

  Next, the control unit 11 determines whether or not the bit rate of the reference content has been selected (step S45). That is, it is determined whether the selection information corresponding to the bit rate is specified by the user through the input unit 20. Then, when the bit rate of the reference content is selected (step S45: YES), the control unit 11 proceeds to step S46. When the bit rate of the related content is selected (step S45: NO), the control unit 11 proceeds to step S47.

  In step S46, the control unit 11 acquires a reference content ID from the content attribute information found in step S42.

  On the other hand, in step S47, the control unit 11 acquires the reference content ID from the content attribute information found in step S42. Then, the control unit 11 generates a related content ID by applying the data including the acquired reference content ID and the bit rate selected in step 45 to the hash function (step S48).

  Note that the processing in step S49 is the same as the processing in step S17 shown in FIG.

  According to the first embodiment, the node Nn as the user node obtains the related content ID by hashing the reference content ID of the reference content and the data including the bit rate indicated by the special keyword with the hash function. Configured to generate. As a result, in addition to the above-described effects, related content IDs that do not overlap with content IDs of other content can be generated more efficiently and easily.

  In addition, the node Nn as the user node registers a special keyword representing related information indicating the relationship between the reference content and the related content in the content catalog information in the content attribute information of the reference content. Composed. As a result, the node Nn can quickly acquire a special keyword in addition to the reference content ID from the content catalog information. Therefore, the related content ID can be generated immediately. Since the data amount of the special keyword is smaller than the data amount of the related content ID, the data size of the content catalog information can be reduced.

  Further, since the relationship between the reference content and the related content is presented to the user by the special keyword, the related content can be easily specified by the user.

  The related content ID is not registered in the content catalog information, but is generated based on the special keyword registered in the content catalog information. As a result, the search for the location of the related content is also performed based on the reference content ID registered in the content catalog information, so that the content management can also be performed for the related content based on the content catalog information.

(Example 2)
Next, a second embodiment of the operation of the content distributed storage system S will be described. In the second embodiment, a process that is a more specific example of the basic process shown in FIGS. 5 and 6 will be described. Specifically, the process of generating the related content ID in step S3 shown in FIG. 5 is a process of generating the related content ID as a serial number from the reference content ID in step S23 shown in FIG. That is, the content ID generation rule is defined as “the related content ID is a serial number from the reference content ID”. Also, in the second embodiment, as in the first embodiment, the process of selecting either the reference content or the related content in step S13 shown in FIG. 6 is performed, and the user selects either the reference content or the related content in step S45 shown in FIG. It was set as the process which selects.

  In the second embodiment, only the parts different from the first embodiment will be described using the flowcharts of FIGS. 7 and 8 used in the first embodiment. Processing of the content providing server described later is executed by a CPU of the content providing server (not shown).

  In step S21 shown in FIG. 7 of the second embodiment, the content providing server, according to the content input instruction, the reference content (first episode) to be input and a plurality of related contents (second to 24th episodes) following this content. For example) from an external device. In addition, the content providing server reads information indicating the content name, the publication start date / time, and the publication end date / time of each of the reference content and the related content from the external device.

  In step S23 shown in FIG. 7 of the second embodiment, the content providing server adds a numerical value corresponding to the number of stories corresponding to each related content to the numerical value represented by the reference content ID. For example, in the case of the second episode, “1” is added to the reference content ID. In the case of the third episode, “2” is added to the reference content ID. By adding the above-described numerical value to the reference content ID, the content providing server generates each related content ID. Each related content ID is assigned to each related content.

  In step S27 shown in FIG. 7 in the second embodiment, the content providing server adds the number of stories of the reference content and the related content (for example, episodes 1 to 24) to the content attribute information of the reference content. Add as a special keyword.

  Other processes shown in FIG. 7 are the same as those in the first embodiment.

  Next, in step S44 shown in FIG. 8 in the second embodiment, the control unit 11 of the user node displays selection information corresponding to each story indicated by the extracted special keyword on the display unit 16 and prompts the user to select. . For example, the display unit 16 displays selection information such as “first story”, “second story”, “third story”,.

  Next, in step S45 shown in FIG. 8 in the second embodiment, the control unit 11 determines whether or not the number of stories of the reference content has been selected. If the number of stories of the reference content is selected (step S45: YES), the control unit 11 proceeds to step S46. When the number of related contents is selected (step S45: NO), the control unit 11 proceeds to step S47.

  Then, in steps S47 and S48 shown in FIG. 8 in the second embodiment, the control unit 11 acquires the reference content ID. The control unit 11 adds a numerical value corresponding to the number of stories corresponding to each related content to the numerical value represented by the acquired reference content ID. For example, the control unit 11 adds “1” to the reference content ID in the case of the second episode. Further, the control unit 11 adds “2” to the reference content ID in the case of the third episode. By executing the processing described above, a related content ID that is a serial number from the reference content ID is generated.

  According to the second embodiment, the node Nn as the user node adds (subtracts) a numerical value represented by the reference content ID of the reference content and a numerical value corresponding to, for example, the number of stories indicated by the special keyword. In this way, the related content ID is generated. As a result, in addition to the above-described effects, related content IDs that do not overlap with content IDs of other content can be generated more efficiently and easily.

Example 3
In the first embodiment and the second embodiment, the content catalog information is configured to be stored in advance (locally) in each node Nn. In the case of a system in which the user node does not store all or part of the content catalog information, the user node obtains necessary content catalog information from another node Nn and performs a keyword search after starting the search. It may be configured. A system in which the user node does not store all or part of the content catalog information is, for example, a content distribution storage system in which content catalog information is distributed and stored at a plurality of nodes Nn. Alternatively, the user node may be configured to perform a keyword search by acquiring the content catalog information from the content providing server after starting the search.

  According to the third embodiment, the data amount of the content catalog information can be reduced also in the content providing server that stores the content catalog information and other nodes N.

Example 4
The first to third embodiments are configured to perform keyword search using content catalog information held by the user node. In the case of a system in which the user node does not store the content catalog information, the user node transmits a search request message including a search keyword by DHT routing to another node Nn that stores the content catalog information. You may comprise. A system in which the user node does not store content catalog information is, for example, a content distribution storage system in which content catalog information is distributed and stored at a plurality of nodes Nn. In this case, the other node Nn that has received the search request message performs a keyword search using the keyword included in the message, and acquires content attribute information including the reference content ID and the special keyword. The acquired content attribute information is returned to the user node that sent the search request message. Then, the user node generates a related content ID from the reference content ID and the special keyword included in the received content attribute information.

  Or you may comprise as follows. The user node transmits a search request message including the search keyword to the content providing server. The content providing server that has received the search request message performs a keyword search using the keyword included in the message. Content attribute information including the reference content ID and special keywords is acquired by the search. You may comprise so that the acquired content attribute information may be returned (response) to the user node of the transmission source of a search request message.

  According to the fourth embodiment, the content providing server that stores the content catalog information and other nodes N can reduce the data amount of the content catalog information and can promptly respond to the search request message.

(Example 5)
In the first to fourth embodiments, the user node is configured to generate the related content ID. In the case of a system in which the user node does not store the content catalog information, the user node may be configured to generate a related content ID in another node Nn that stores the content catalog information. A system in which the user node does not store content catalog information is, for example, a content distribution storage system in which content catalog information is distributed and stored at a plurality of nodes Nn. In this case, the user node transmits a related content ID generation request message including the search keyword to the other node Nn that stores the content catalog information by DHT routing. The other node Nn that has received the related content ID generation request message performs a keyword search using the keyword included in the message. The reference content ID and the special keyword are acquired by the search. A related content ID is generated from the acquired reference content ID and special message. The reference content ID and the related content ID are returned to the user node that is the transmission source of the related content ID generation request. Alternatively, the user node may be configured to cause the content providing server to generate a related content ID.

  According to the fifth embodiment, the data amount of the content catalog information can be reduced also in the content providing server that stores the content catalog information and other nodes N, and the search request message can be quickly answered. In addition, it is possible to reduce the processing load for the user node to generate the related content ID.

(Example 6)
In the first to fifth embodiments, the related information indicating the relationship between the reference content and the related content is configured to be registered in the content catalog information as a special keyword. The related information may not be registered in the content catalog information but may be provided from the outside to the node Nn that generates the related content ID. This configuration can be applied, for example, to a case where a plurality of fixed bit rate moving image distribution systems or another content database are linked. Further, the related information may be configured to be set as default in all nodes Nn participating in the content storage system S.

  The present invention can also be applied to a system that does not use content catalog information, for example, a system in which a search request is transmitted to another node Nn and a search result is returned. Can be improved.

  In addition, although the content distributed storage system S in the said embodiment was demonstrated on the assumption that it was formed by the algorithm using DHT, this invention is not limited to this.

8 Network 9 Overlay Network 11 Control Unit 12 Storage Unit 13 Buffer Memory 14 Decoder Unit 15 Video Processing Unit 16 Display Unit 17 Audio Processing Unit 18 Speaker 19 Communication Unit 20 Input Unit 21 Bus Nn Node S Content Distributed Storage System

Claims (11)

The node device in a content distributed storage system in which a plurality of content data is distributed and stored in a plurality of node devices that can communicate with each other via a network,
Reference content search information for searching for the location of reference content data serving as a reference in the plurality of content data, and related information indicating a relationship between the reference content data and at least one or more related content data related thereto Search information acquisition means for acquiring
Related search information generating means for generating related content search information from the reference content search information and the related information;
Based on the related content search information generated by the related search information generation means, related content acquisition means for searching for the location of the related content data and acquiring the related content data;
A node device comprising: The node device according to claim 1,
Search information storage means for storing search information in which content attribute information of the reference content data and content attribute information including the reference content search information of the reference content data is described;
The related search information generating means generates the related content search information from the reference content search information and the related information stored in the search information storage means. In the node device according to claim 1 or 2,
The search information acquisition means acquires search information in which the reference content search information that is identification data unique to the reference content data is associated with the related information,
The related search information generation means generates the related content search information by hashing data including the reference content search information and the related information with a predetermined hash function. The node device according to claim 3, wherein
The reference content search information is identification data unique to the reference content data, and the related content search information is identification data unique to the related content data;
The related search information generating means generates the identification data of the related content data by adding or subtracting a predetermined value to a numerical value represented by the identification data of the reference content data. Node device. The node device according to claim 4, wherein
The related search information generation means adds or subtracts a numerical value corresponding to information (for example, the number of stories) indicated in the related information to or from the number represented by the identification data of the reference content data. A node device that generates the identification data of content data. In the node apparatus as described in any one of Claims 1 thru | or 5,
The search information acquisition means acquires search information in which the reference content search information is associated with a keyword representing the related information as the related information,
The related search information generating means generates related content search information from the reference content search information and the keyword. The node device according to claim 6, wherein
The search information acquisition means acquires search information in which the reference content search information is associated with the keyword as the related information,
Display means for displaying selection information corresponding to the information indicated by the keyword;
When the selection information is designated by the user via the input means, the related search information generation means obtains the related content search information from the keyword corresponding to the designated selection information and the reference content search information. Generate
The node device characterized in that the related content acquisition means acquires the related content data based on the related content search information generated by the related search information generation means.   A node processing program for causing a node device according to any one of claims 1 to 7 to function. In a content distributed storage system in which a plurality of content data are distributed and stored in a plurality of node devices that can communicate with each other via a network,
The node device is
Reference content search information for searching for the location of reference content data serving as a reference in the plurality of content data, and related information indicating a relationship between the reference content data and at least one or more related content data related thereto Search information acquisition means for acquiring
Related search information generating means for generating related content search information from the reference content search information and the related information;
Based on the related content search information generated by the related search information generation means, related content acquisition means for searching for the location of the related content data and acquiring the related content data;
A content distributed storage system comprising: In a content distributed storage system in which a plurality of content data are distributed and stored in a plurality of node devices that can communicate with each other via a network,
One node device sets request information indicating a request for reference content search information for searching for a location of at least one related content data related to reference content data serving as a reference in the plurality of content data to another Comprising request information transmitting means for transmitting to a node device or server device;
The other node device or server device is:
Request information receiving means for receiving the request information transmitted from the one node device;
In accordance with the request information received by the request information receiving means, the reference content search information for searching for the location of the reference content data and the relationship between the reference content data and the related content data related thereto are indicated. Search information acquisition means for acquiring related information;
Related search information generating means for generating related content search information from the reference content search information and the related information;
Related content search information transmitting means for transmitting the related content search information generated by the related search information generating means to the one node device;
With
The one node device is:
Related content search information receiving means for receiving the related content search information transmitted from the other node device or server device;
Based on the related content search information received by the related content search information receiving means, related content acquisition means for searching for the location of the related content data and acquiring the related content data;
A content distributed storage system comprising: A related content acquisition method in a content distributed storage system in which a plurality of content data is distributed and stored in a plurality of node devices that can communicate with each other via a network,
The node device includes reference content search information for searching for a location of reference content data serving as a reference in the plurality of content data, and the reference content data and at least one or more related content data related thereto. Acquiring related information indicating the relationship;
The node device generating related content search information from reference content search information and the related information;
The node device searches for the location of the related content data based on the generated related content search information and obtains the related content data;
A related content acquisition method comprising:

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