JP2008135952A - Tree type content broadcasting system, content catalog information generation method, and node device or the like - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tree type content broadcasting system which is capable of reducing the amount of data of content catalog information by reducing a distribution burden to a specific device like a catalog management server, a content catalog information generation method, a node device or the like, and a node processing program. <P>SOLUTION: In the tree type content broadcasting system constituted of a plurality of node devices, the plurality of node devices are connected like a tree through communication means while forming a plurality of hierarchies with a broadcasting device as a top, and content data broadcast by the broadcasting device are successively transferred from the node device in the highest hierarchy to node devices in lower hierarchies. Each node device includes a content reception means for receiving the broadcast content data and a catalog generation means for generating content catalog information with which at least content specifying information for specifying the received content data is registered. <P>COPYRIGHT: (C)2008,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, a content distribution storage system that distributes content data to a plurality of node devices (distributed storage) is known. Has been enhanced. The location of the content data distributed and stored in this way can be efficiently searched using a distributed hash table (hereinafter referred to as DHT (Distributed Hash Table)) as disclosed in Patent Document 1, for example. The DHT is stored in each node device, and node information (for example, including IP addresses and port numbers) indicating a plurality of node devices to which various messages are to be transferred is registered in the DHT. .

  Each node device has content catalog information in which information (for example, content name, genre, artist name, etc.) regarding content data that is distributed and stored is registered. For example, each node device registered in the content catalog information. By sending a message (query) for searching (discovering) the location of desired content data to another node device based on the content name, the message is sent by a plurality of relay node devices according to the DHT. The node information is acquired from the node device of the management source that is transferred to the node device of the management source where the content data is located and finally reaches the message. Accordingly, the node device that has transmitted the message can request the content data from the node device that stores the content data related to the search, and can receive the content data.

By the way, the content catalog information is distributed (distributed) to all the node devices participating in the distributed content storage system, for example, from a catalog management server managed by a system administrator or the like. Further, whenever new content data is input (stored for the first time) in a certain node device on the distributed content storage system, new content catalog information corresponding to this is distributed to all the node devices.
JP 2006-197400 A

  However, if the content catalog information is distributed from, for example, a catalog management server to all node devices participating in the content distributed storage system, there is a problem that the burden on the catalog management server increases. In addition, if information related to all content data stored in a plurality of node devices in a content distributed storage system is registered in the content catalog information, the amount of data becomes enormous and a sufficient storage capacity is secured on each node device side. Furthermore, it becomes difficult for the user to search for desired content data.

  The present invention has been made in view of the above problems and the like, and is a tree-type content broadcasting system and content capable of suppressing the distribution burden of a specific device such as a catalog management server and suppressing the data amount of content catalog information. It is an object to provide a catalog information creation method, a node device, and a node processing program.

  In order to solve the above problems, the invention according to claim 1 is a tree-type content broadcasting system formed by a plurality of node devices, wherein the plurality of node devices have a plurality of hierarchies with the broadcasting device as the highest level. A tree-type content broadcast that is connected in a tree shape through communication means while being formed so that content data broadcast by the broadcasting device is sequentially transferred from the node device in the upper layer to the node device in the lower layer The catalog in the node device in the system for creating content catalog information in which content receiving means for receiving the broadcasted content data and content specifying information for specifying at least the received content data are registered Creating means.

  According to the present invention, since the content catalog information in which the content specifying information for specifying the content data is registered is created based on the content data broadcast in the tree type content broadcasting system, each node device Can independently create content catalog information, reduce the distribution burden of a specific device such as a catalog management server, and reduce the amount of data in the content catalog information.

  According to a second aspect of the present invention, in the node device according to the second aspect, the presenting means for presenting the content specifying information registered in the content catalog information to a user, and any of the content from the user Receiving means for receiving specification of specific information, and content acquisition means for acquiring content data corresponding to the specified content specific information, wherein the content acquisition means includes a plurality of content data in a plurality of node devices. A node device in a distributed and distributed content storage system, wherein the content data is obtained from a node device storing content data corresponding to the specified content specifying information.

  According to this invention, each node device can acquire desired content data from the node device storing the content data in the content distributed storage system using the created content catalog information.

  According to a third aspect of the present invention, in the node device according to the first or second aspect, a reproduction unit that reproduces the received content data and a reproduction time measurement unit that measures a reproduction time of the content data related to the reproduction. The catalog creating means registers content specifying information for specifying content data whose measured reproduction time is equal to or longer than a predetermined time in the content catalog information.

  According to the present invention, content catalog information in which content specifying information for specifying content data desired by the user is registered can be created in consideration of zapping by the user.

  According to a fourth aspect of the present invention, in the node device according to the first or second aspect, in the tree-type content broadcasting system, the plurality of node devices form a plurality of hierarchies for each of a plurality of broadcast channels. Content data that is connected in a tree shape via communication means and broadcasts different content data, and that reproduces the received content data, and reproduction of the content data related to the reproduction for each channel Measuring means for measuring time, wherein the catalog creating means contains content specifying information for specifying content data broadcast on a broadcast channel whose measured playback time is a predetermined time or more. It is registered in catalog information.

  According to this invention, not only content specifying information for specifying content data desired by a user, but also a rich content catalog in which content specifying information for specifying content data broadcast on the broadcast channel is registered. Information can be created.

  According to a fifth aspect of the present invention, in the node device according to any one of the first to fourth aspects, the catalog creating means specifies content for specifying content data related to the received content data. Information is registered in the content catalog information.

  According to the present invention, it is possible to create rich content catalog information that more suits the user's preference.

  According to a sixth aspect of the present invention, in the node device according to any one of the first to fourth aspects, the catalog creating means is for specifying content data to be recommended on the broadcast side of the content data. Content specifying information is registered in the content catalog information.

  According to the present invention, it is possible to create enriched content catalog information including advertising effects.

  The invention according to claim 7 is the node device according to any one of claims 1 to 6, wherein the content specifying information is included in a broadcast stream of the content data at a predetermined interval, and the catalog The creating means acquires the content specifying information to be registered in the content catalog information from the broadcast stream.

  According to the present invention, it is possible to easily acquire content specifying information to be registered in the content catalog information during the broadcast of the content data.

  According to an eighth aspect of the present invention, in the node device according to any one of the first to sixth aspects, the catalog creating means sends the content specifying information to be registered in the content catalog information from the broadcasting device. It is characterized by acquiring.

  According to the present invention, it is possible to acquire content specifying information to be registered in the content catalog information even after the content data has been broadcast.

  According to a ninth aspect of the present invention, in the node device according to any one of the first to seventh aspects, the content specifying information for which a reference time has elapsed since registration in the content catalog information is obtained from the content catalog information. It further comprises specific information deleting means for deleting.

  According to the present invention, the content catalog information can be adjusted so as not to have an enormous amount of data.

  Invention of Claim 10 WHEREIN: In the node apparatus as described in any one of Claims 1 thru | or 7, when the registration number of the said content specific information registered into the said content catalog information exceeds reference | standard number, It is further characterized by further comprising specific information deleting means for deleting the content specific information from the content catalog information in descending order of registration.

  According to the present invention, the content catalog information can be adjusted so as not to have an enormous amount of data.

  The invention according to claim 11 is the node device according to claim 9, wherein reference time setting means for setting the reference time for each type of content data, and reproduction means for reproducing the received content data. Reproduction frequency calculation means for calculating the reproduction frequency of the content data for each type of the content data, and the reference time setting means for each type according to the reproduction frequency for each type of the content data And the specific information deleting means deletes the content specific information corresponding to the type for which the reference time has elapsed since registration in the content catalog information from the content catalog information. And

  According to the present invention, it is possible to create content catalog information in which more content specifying information corresponding to a type with high user preference is registered.

  The invention according to claim 12 is the node device according to claim 10, wherein reference number setting means for setting the reference number for each type of the content data, and reproduction means for reproducing the received content data. Reproduction frequency calculation means for calculating the reproduction frequency of the content data for each type of the content data, and the reference number setting means for each type according to the reproduction frequency for each type of the content data The specific information deleting means deletes the content specific information corresponding to the type whose registered number of content specific information exceeds the reference number from the content catalog information. .

  According to the present invention, it is possible to create content catalog information in which more content specifying information corresponding to a type with high user preference is registered.

  The invention of a node processing program according to a thirteenth aspect causes a computer to function as the node device according to the first to twelfth aspects.

  The invention according to claim 14 is a tree-type content broadcasting system formed by a plurality of node devices, wherein the plurality of node devices form a plurality of hierarchies with the broadcasting device as the highest level via communication means. A tree-type content broadcasting system that is connected in a tree shape and that is broadcasted by the broadcasting device so that the content data is sequentially transferred from the node device in the upper layer to the node device in the lower layer. Comprises content receiving means for receiving the broadcasted content data, and catalog creation means for creating content catalog information in which content specifying information for specifying at least the received content data is registered. It is characterized by.

  The invention according to claim 15 is a tree-type content broadcasting system formed by a plurality of node devices, wherein the plurality of node devices form a plurality of hierarchies with the broadcasting device as the highest level via communication means. A content catalog information creation method in a tree-type content broadcasting system that is connected in a tree shape and content data broadcast by the broadcasting device is sequentially transferred from the node device in the upper layer to the node device in the lower layer. The node device receives the broadcast content data, and creates at least content catalog information in which content specifying information for specifying the received content data is registered. It is characterized by providing.

  According to the present invention, since the content catalog information in which the content specifying information for specifying the content data is registered is created based on the content data broadcast in the tree type content broadcasting system, each node device Can independently create content catalog information, reduce the distribution burden of a specific device such as a catalog management server, and reduce the amount of data in the content catalog information.

  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 communication system.

[ 1. Configuration of communication system ]
First, a schematic configuration and the like of the communication system according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a diagram illustrating an example of a connection mode of each node device in the communication system according to the present 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 The Home) (line device) 6 and communication line (for example, telephone line, optical cable, etc.) 7 etc., a network such as the Internet (real world communication network, an example of communication means) 8 is constructed. ing. A router for transferring data (packets) is appropriately inserted in the network (communication 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. Such serial numbers and IP addresses are not duplicated among a plurality of nodes.

  The communication system S according to the present embodiment is a peer-to-peer network system formed by participation of any one of the nodes Nn among the nodes Nn, as shown in the upper frame 100 of FIG. ing. 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.

  Further, the communication system S is roughly divided into a content distribution (type) storage system (content distribution storage system) and a tree-type content broadcast (distribution) system.

  FIG. 2 is a conceptual diagram of the content distributed storage system and the tree-type content broadcasting system.

  In the content distributed storage system SX1, content data Cj (j = 1, 2, 3,...) Is distributed and stored (content data Cj is stored in a plurality of nodes Nn participating in the system SX1. The node is arbitrary, for example, stored in the node N7 or the like, and one node Nn (for example, the node N7) self-responds to a request from another node Nn (for example, the node N1). The content data Cj stored by is transmitted via the network 8. The content data Cj is input (that is, the content data Cj is first stored in the node Nn in the content distributed storage system SX1), for example, by the content input server SA1.

  On the other hand, in the tree-type content broadcasting system SX2, the node N10 (which may be a content broadcasting server having the function of the connection mode management server SA3) as an example of a broadcasting device is set as the highest level (vertex). A plurality of nodes Nn participating in SX2 (in the example of FIG. 2, nodes N11 to N17...) Are connected in a tree shape via the network 8 while forming a plurality of hierarchies, and broadcast (distributed) by the node N10. The broadcast stream including the content data Cj is sequentially transferred from the upper layer node Nn (for example, the node N10) to the lower layer node Nn (for example, the node N15). The content data Cj is input to the node N10 by the content input server SA1, for example.

  Here, each node Nn can participate not only in either one of the content distributed storage system SX1 and the tree-type content broadcasting system SX2 (in the example of FIG. N1 is participating in both systems).

[ 1-1. Configuration and Function of Content Distributed Storage System SX1 ]
Next, the content distributed storage system SX1 will be described with reference to FIG.

  The content distributed storage system SX1 is realized by a specific algorithm, for example, an algorithm using a DHT (Distributed Hash Table). Each node Nn participating in the content distributed storage system SX1 is assigned a node ID, which is unique identification information. The node ID is, for example, an IP address individually assigned to each node Nn. Alternatively, it is a value obtained by hashing the production number with a common hash function (for example, SHA-1 or the like) (for example, the bit length is 160 bits), and is distributed without being distributed in one ID space as shown in FIG. Will be.

  In addition, participation in the content distributed storage system SX1 is performed when any node Nn (for example, the node N8) that has not participated participates in any node Nn (for example, a contact node that always participates in the system SX1). This is done by sending a participation message indicating a participation request.

  As described above, the node ID obtained (hashed) by the common hash function has a very low probability of having the same value if the IP address or the manufacturing number is different. The node ID needs to have a number of bits that can accommodate the maximum number of nodes that can be operated. For example, if a 128-bit number is used, 2 ^ 128 = 340 × 10 ^ 36 nodes can be operated. Since the hash function is publicly known, detailed description thereof is omitted.

  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 SX1, and specifically, a node including the node ID, IP address, and port number of the node Nn that is moderately separated in the ID space A plurality of pieces of information (transfer destination node information) are registered.

  One node Nn participating in the content distributed storage system SX1 registers in the routing table the node information of the minimum necessary node Nn among all the nodes Nn participating in the system SX1, With respect to the node Nn that does not know (store) the node information, various messages are transferred between the nodes Nn to be delivered.

  Here, the routing table using DHT will be described in detail with reference to FIGS. 3 and 4.

  FIG. 3 is a diagram illustrating an example of a routing table using the DHT held by the node N2, and FIG. 4 is a conceptual diagram illustrating an example of an ID space of the DHT.

  3 and 4, for convenience of explanation, the bit length of the node ID is 2 bits × 3 digits = 6 bits, and each digit is represented by a quaternary number (an integer of 0 to 3) (actually, A longer bit length is used, and each digit is also divided into, for example, 4 bits and expressed by a hexadecimal number of 0 to f).

  In the example of FIG. 3, the routing table using DHT is composed of level 1 to level 3 tables (divided into a plurality of levels), and each level table entry includes node information for each area. The node ID is registered in association with the IP address and port number of the node Nn corresponding to the node ID. Each area in the table of each level is an area obtained by dividing the DHT node ID space. For example, as shown in FIG. 4, in the level 1, the entire ID space of the DHT is divided into four, and the area where the node IDs “000” to “033” are present is the 0XX area, “100” to “133” The area where the node ID exists is the 1XX area, the area where the node IDs "200" to "233" exist is the 2XX area, and the area where the node ID "300" to "333" exists is the 3XX area. . In level 2, the area of level 1 (that is, the area from 0XX to 3XX) is further divided into four, for example, the area of 1XX is divided into four, and the area where the node IDs “100” to “103” exist is 10X. Area, an area where node IDs “110” to “113” exist are 11X areas, an area where node IDs “120” to “123” exist are 12X areas, and node IDs “130” to “133” exist The area in which is present is defined as a 13X area.

  For example, if the node ID of the node N2 is “122”, as shown in FIG. 3, the table of the 1XX area at the level 1 of the node N2 (the area where the self (that is, the own node) exists) The area where the self node ID and IP address (the IP address is own, so it is not necessary to register it in the routing table) etc. is registered and does not exist (that is, 0XX area, 2XX area) , And 3XX area), node IDs and IP addresses of other arbitrary nodes Nn are registered.

  In addition, in the table of the 12X area (the area where the self exists) in the level 2 of the node N2, as shown in FIG. 3, the self node ID and the IP address (the IP address is own) In the areas where the self does not exist (that is, the 10X area, the 11X area, and the 13X area), etc., nodes of other arbitrary nodes Nn, respectively, are registered. ID, IP address, etc. are registered.

  Further, in the level 3 of the node N2, as shown in FIG. 3, the node IDs and IP addresses having node IDs “120” to “122” are registered in the routing table. Is not necessary).

  In the examples of FIGS. 3 and 4, since the bit length of the node ID is 3 digits × 2 bits, it can be covered with a table for three levels of levels 1 to 3. However, if the bit length of the node ID increases, (For example, if the bit length of the node ID is 16 digits × 4 bits, a table for 16 levels is required).

  Thus, in the routing table using DHT in the present embodiment, the area becomes narrower as the level increases.

  Such DHT is given, for example, when a non-participating node participates in the content distributed storage system SX1.

  By the way, in the content distributed storage system SX1, as described above, various content (for example, movies, music, etc.) data is distributed (stored) in a plurality of nodes Nn (in other words, content data). Cj is replicated and replicas of the replica information are distributed and stored), for example, the content data C1 of the movie whose title is XXX is stored in the node N1 and the node N5, while the node N7 includes The content data C2 of the movie whose title is YYY is stored in a distributed manner among a plurality of nodes Nn (hereinafter referred to as “content holding nodes”).

  In addition, information such as a content name (title) and a content ID (identification information unique to each content) is added to the content data Cj.

  This content ID is generated, for example, by hashing a content name + an arbitrary numerical value (or may be the first few bytes of the content data Cj) with a hash function common to the node ID (node) Placed in the same ID space as the ID). Alternatively, the system operator may give a unique ID value (same bit length as the node ID) for each content.

  Further, the location of the content data Cj distributed and stored in this manner, that is, the node information (for example, including the IP address and port number) of the node Nn storing the content data Cj and the content data Cj are associated. Index information including a set of content IDs is stored in a node Nn (hereinafter referred to as “root node” or “root node of content (content ID)”) as a management source of the location of the content data Cj ( (Stored in the index cache) and managed.

  For example, the index information of the content data C1 of the movie whose title is XXX is managed by the node N6 which is the root node of the content (content ID), and the index information of the content data C2 of the movie whose title is YYY is the content ( Managed by the node N3 which is the root node of the content ID). In other words, since the root node is divided for each content, the load is distributed, and the same content data Cj (the same content ID) is stored in a plurality of content holding nodes. However, the index information of the content data Cj can be managed by one root node. Further, such a root node is determined to be, for example, a node Nn having a 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 the desired content data Cj, the node Nn that desires to acquire the content data Cj (hereinafter referred to as “user node”) receives content catalog information (described later) by the user. A content location inquiry (search) message (query) including the content ID of the content data Cj selected from the content list (also referred to as a content list) and its own node information is generated, and this is stored in the other table according to the routing table using its own DHT. Send to node Nn. That is, the user node sends a content location inquiry (search) message toward the root node. As a result, the content location inquiry (search) message finally arrives at the root node by DHT routing using the content ID as a key.

  The content ID included in the content location inquiry (search) message may be generated by the user node by hashing the content name with the common hash function.

  FIG. 5 is a conceptual diagram showing an example of the flow of a content location inquiry (search) message sent from a user node in the DHT ID space.

  In the example of FIG. 5, for example, the node N1, which is a user node, refers to the DHT level 1 table, and is closest to the content ID (eg, 112) included in the content location inquiry (search) message ( For example, the IP address and port number included in the node information of, for example, the node N2 having a node ID (which matches the higher digits more) are acquired, and the content location inquiry (search) message is sent to the IP address and port number. Send.

  On the other hand, the node N2 receives the content location inquiry (search) message, refers to the DHT level 2 table, and is closest to the content ID included in the content location inquiry (search) message. The IP address and port number included in the node information of, for example, the node N3 having the node ID (for example, the higher digit matches more) are acquired, and the content location inquiry (search) message is sent to the IP address and port number. Forward.

  On the other hand, the node N3 receives the content location inquiry (search) message, refers to the table of its own DHT level 3, and is closest to the content ID included in the content location inquiry (search) message. If the node ID (for example, the higher-order digits match more) is itself, that is, if it recognizes that it is the root node of the content ID, it corresponds to the content ID included in the content location inquiry (search) message The index information to be acquired is acquired from the index cache, and the index information is returned to the user node that is the transmission source of the content location inquiry message. As a result, the user node connects to, for example, the node N7 that is the content holding node storing the desired content data Cj, and transmits a content transmission request message (request information indicating a transmission request for the content data Cj). From there, it becomes possible to receive provision of the content data Cj.

  Alternatively, the node N3, which is the root node, sends a content transmission request message (including node information of the user node to the content holding node indicated in the node information included in the index information, and the content data Cj Request information indicating a request for transmission). As a result, the user node can connect to the content holding node such as the node N7 and receive the content data Cj.

  The user node obtains the index information from the relay node (for example, the cache node of the node N2) that caches the same index information as the root node until the content location inquiry message reaches the root node. It can also be acquired (received).

  In addition, the user node notifies the root node that the content data Cj has been stored (in other words, the fact that the user node holds the content data Cj, is participating in the system SX1) A publish (registration notification) message (content data has been saved, so that a request for registration of node information, etc. is included) including the content ID of the content data Cj and its own node information, etc. Registration message) is generated, and the publish message is transmitted toward the root node. As a result, the publish message arrives at the root node by DHT routing using the content ID as a key in the same manner as the content location inquiry (search) message, and the root node is a node included in the received publish message. Index information including a set of information and content ID is registered (stored in the index cache area). Thus, the user node becomes a new content holding node that holds the content data Cj.

  Note that the index information including the set of node information and content ID included in the publish message is also registered (cached) in the relay node on the transfer route up to the root node.

  Next, content catalog information used when acquiring content data Cj will be described.

  FIG. 6 is a diagram illustrating an example of information related to content data registered in content catalog information in a certain node. As shown in FIG. 6, in the content catalog information, the content name and content ID, the attribute information, and the registration date are registered. The registration number is a serial number given in the order of registration in the content catalog information. In the example shown in FIG. 6, information related to a maximum of 1000 pieces of content data can be registered in the content catalog information.

  Further, as the attribute information, for example, genre as an example of content data type (if the content is a movie, animation, action, horror, comedy, love story, etc., if the content is music, rock, jazz, pop, classic, etc. , If the content is a broadcast program, drama, sports, news, movie, music, animation, variety, etc.), artist name (singer, group, etc. if the content is music), performer (if the content is a movie or broadcast program) Cast), director name (when the content is a movie), outline of the content (summary), keywords given by the content creator, content data size, and the like.

  Information regarding such content data can be used as a search keyword when the user searches for desired content data Cj from a large amount of content data Cj. For example, when the user inputs “jazz” as a search keyword, all content data Cj corresponding to “jazz” is searched, and the content name, artist name, etc. of the searched content data are presented to the user in a selectable manner. It will be.

  FIG. 7 is a conceptual diagram showing an example of the transition of the display format of the music catalog at a certain node. The content catalog information described above is incorporated into such a music catalog (which may be a movie catalog). In the example shown in FIG. 7A, when, for example, jazz is input as a search keyword from the displayed genre list and searched, the artist name corresponding to the jazz as shown in FIG. 7B is displayed. A list is displayed, and an artist “AABBC”, for example, is input from the artist name list as a search keyword, and is searched for, as shown in FIG. 7C (for example, the artist). A list of song titles is displayed.

  When the user selects a desired song title from the song title list via the input unit, the content ID of the song data (an example of content data) is acquired, and includes the content ID as described above. The content location inquiry message is sent toward the root node. Note that the content ID does not have to be described in the content catalog information. In this case, each node has, for example, a common hash function obtained by hashing the above-described node ID with the content name included in the attribute information + an arbitrary numerical value. The content ID may be generated by hashing.

  When the content catalog information as described above is distributed to all nodes participating in the content distributed storage system SX1, for example, from the catalog management server SA2 managed by the system administrator or the like, the catalog management server SA2 When the information related to all the content data stored in a plurality of nodes in the content distributed storage system SX1 is stored in the content catalog information becomes enormous and the amount of data is large. It is necessary to secure the capacity on each node side (or delete information on a part of the necessary content data), and it becomes difficult for the user to search for desired content data.

  For this reason, in the present embodiment, the node that receives the content data Cj broadcast in the tree-type content broadcasting system SX2 is configured to create and use unique content catalog information based on the content data Cj. .

[ 1-2. Configuration and function of tree-type content broadcasting system SX2 ]
Next, the tree-type content broadcasting system SX2 will be described with reference to FIG.

  The tree-like topology (connection mode) in the tree-type content broadcasting system SX2 is managed by, for example, the connection mode management server SA3 (in the case where the content broadcasting server broadcasts the content module Cj, the topology is managed by the content broadcasting server). May be). Specifically, the connection mode management server SA3 includes node information (for example, IP address and port number) of each node Nn participating in the tree type content broadcasting system SX2, and a connection mode (topology) between the nodes Nn. ) And connection status information including connection status and the like are managed using a database. Such a tree-like topology is formed for each of a plurality of broadcast channels (in the example shown in FIG. 2, only one broadcast channel is shown for convenience of explanation), and the connection state information Is managed for each broadcast channel. Different content data Cj is broadcast on each broadcast channel.

  Participation in the tree-type content broadcasting system SX2 is performed by a non-participating node Nn transmitting a participation message indicating a participation request to the connection mode management server SA3. The broadcast schedule table in each broadcast channel (in other words, the program table in which the broadcast date and time and contents are defined) can be acquired by each node Nn, and each node Nn is designated by the user based on the broadcast schedule table. The participation message for the broadcast channel is transmitted. Then, in response to the participation message, the connection mode management server SA3 uses the connection state information to select a node Nn as a connection destination to which the non-participating node Nn should be connected in the designated broadcast channel, A connection destination introduction message (introduction information for introducing the node Nn to be connected) including the node information of the selected node Nn is transmitted to the non-participating node Nn. For example, the connection mode management server SA3 identifies a node Nn in which the number of nodes Nn directly connected as a lower hierarchy of the node Nn is less than the allowable number of connections (for example, priority is given to a node Nn located in a higher hierarchy) When there are a plurality of identified nodes Nn, for example, one node Nn having the highest transfer capability is identified from those nodes Nn (even if one node Nn is identified at random from these nodes Nn) This is good), and this is selected as the node Nn to be connected.

  In this way, the non-participating node Nn that has received the connection destination introduction message from the connection mode management server SA3 establishes a connection with the already participating node Nn based on the node information included in the connection destination introduction message. The content data Cj is requested to be transferred to the node Nn. As a result, the non-participating node Nn newly participates in the tree-type content broadcasting system SX2 related to the broadcast channel, and receives the content data Cj transferred (broadcast) from the already participating node Nn. It will be.

  In addition, the node Nn that has not participated not only participates in the tree-type content broadcasting system SX2 for the first time, but also leaves itself from the system SX2 due to power-off or communication failure, and then rejoins the system SX2. Alternatively, when the transfer of the content data Cj is interrupted due to withdrawal or transfer stop of the upper layer node Nn from the system SX2, a participation message is transmitted to the connection mode management server SA3, and the connection mode management server SA3 A connection destination introduction message is acquired.

  In addition, when content data Cj is newly input in the content distributed storage system SX1 described above, or according to the broadcast schedule table of the content data Cj, the content data Cj is received by the content input server SA1, for example, by a tree type content broadcast system. It is sent to the highest node Nn in SX2, is broadcast from the highest node Nn (for example, node N10) in a streaming manner, for example, as a broadcast stream, and is sequentially transferred from the upper layer node Nn to the lower layer node Nn. become.

  FIG. 8 is a diagram showing a state in which a broadcast stream including content data Cj is broadcast in the tree-type content broadcast system SX2.

  As shown in FIG. 8, for example, a video stream compressed by a compression method such as MPEG and an audio stream are packets (that is, video packets Vk (k = 1, 2, 3...). Are divided into audio packets Al (l = 1, 2, 3,...) And then multiplexed and broadcast. As shown in FIG. 8, each node Nn (for example, node N1) on the halfway path transfers the received packet to the lower layer node Nn, if there is one, and writes it to the buffering (ring buffer memory). (Writing from the position of “Write” shown in FIG. 8) (temporary accumulation). Each node Nn reads out each packet stored in the ring buffer memory (reads from the “Read” position shown in FIG. 8) and reproduces it.

  In such a broadcast stream, as shown in FIG. 8, content specification information packets C having content specification information for specifying content data Cj included therein are inserted (periodically) at predetermined intervals. Has been. That is, a plurality of content specifying information packets C are included in a broadcast stream related to one content data Cj, and the contents of these content specifying information packets C are the same.

  Each node Nn acquires the content specifying information from the content specifying information packet C included in the received broadcast stream, and creates content catalog information based on the acquired content specifying information (the content specifying information, its registration). Number and registration date are registered in the content catalog information).

  Here, the content specifying information included in the content specifying information packet C includes, for example, information related to all content data that can be registered in the content catalog information (for example, content name, content ID, and attribute information). It is. Alternatively, only the minimum information (for example, content name or content ID) necessary for specifying the content data Cj is included in the content specifying information, and other information related to the content data is, for example, content using the content ID as a key. You may comprise so that it may be acquired from management server SA2 or the highest node Nn (for example, node N10).

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

  FIG. 9 is a diagram illustrating a schematic configuration example of the node Nn.

  As shown in FIG. 9, each node Nn includes a control unit 11 as a computer including a CPU having a calculation function, a working RAM, a ROM for storing various data and programs, and various data (for example, content data). (Cj, index information, DHT, etc.) and various programs, etc., a storage unit 12 composed of HD, etc., a buffer memory 13 for temporarily storing received content data Cj, etc., and content data A decoder unit 14 that decodes (decompresses or decodes) encoded video data (video information), audio data (audio information), and the like included in Cj, and a predetermined drawing for the decoded video data A video processing unit 15 that performs processing and outputs the video signal, and the video processing unit 15 A display unit 16 such as a CRT or a liquid crystal display for displaying an image based on the video signal output from the video signal, and D (Digital) / A (Analog) conversion of the decoded audio data into an analog audio signal, which is then amplified by an amplifier Information communication between the audio processing unit 17 to be output, the speaker 18 to output the audio signal output from the audio processing unit 17 as a sound wave, and other nodes Nn, servers SA1 to SA3, and the like through the network 8. A communication unit 20 for performing control, and an input unit 21 (for example, a keyboard, a mouse, or an operation panel, a remote controller, etc.) that receives an instruction from the user and gives an instruction signal corresponding to the instruction to the control unit 11; The control unit 11, the storage unit 12, the buffer memory 13, the decoder unit 14, the communication unit 20, and The input units 21 are connected to each other via a bus 22. As the node Nn, a personal computer, an STB (Set Top Box), a TV receiver, or the like can be applied.

  In addition, the storage unit 12 stores the IP address and port number of a contact node to be accessed when participating in the distributed content storage system SX1, and the IP addresses of the catalog management server SA2 and the connection mode management server SA3. Yes. Furthermore, content catalog information as shown in FIG. 6 is stored in the storage unit 12.

  Further, the buffer memory 13 is composed of, for example, a ring buffer memory as shown in FIG. 8 in the FIFO (First In First Out) format, and the old content data Cj that has already been accumulated by the received new content data Cj packet. Packets are overwritten and sequentially erased.

  In such a configuration, the control unit 11 performs overall control by reading and executing the node processing program and the like stored in the storage unit 12 and the like, and the above-described control unit 11 participates in the content distributed storage system SX1. The process as at least one of the user node, the relay node, the root node, the cache node, and the content holding node is performed.

  In addition, the control unit 11 performs processing as a node Nn located in any hierarchy in the tree by participating in the tree-type content broadcasting system SX2, and receives content reception means, catalog creation means, presentation means, reception means, content acquisition Means, reproduction means, reproduction time measurement means, specific information deletion means, reference time setting means, reference number setting means, reproduction frequency calculation means, and the like.

  Specifically, when the data amount such as content data Cj included in the broadcast stream received in the node Nn participating in the tree-type content broadcast system SX2 is accumulated in the buffer memory 13 more than a certain amount, Under control, the content data Cj is sent to the decoder unit 15 and decoded and reproduced and output via the audio processing unit 18 and the speaker 19 (if the content data Cj is only audio data, it is output as a sound wave from the speaker 19. On the other hand, when the content data Cj includes video data and audio data, it is output as sound waves from the speaker 19 and the video is displayed on the display unit 17).

  At this time, the control unit 11 measures the reproduction time of the content data Cj related to reproduction, and the reproduction time is a predetermined time (this time is zapping by the user (for example, the user operates the input unit 21 to operate the desired content). For example, although it is not particularly limited, for example, it is set to 10 minutes to 20 minutes) or more, the content data The content catalog information of the content data Cj is created by registering the content specification information for specifying Cj in the content catalog information. Thereby, each user can obtain unique content catalog information in which content specifying information of desired content data Cj is registered. In creating the content catalog information, not only the content specifying information of the received content data C10, for example, content specifying information such as other content data C11 broadcast on the broadcast channel is also used as the content catalog information. You may comprise so that it may register together.

  In addition, for example, content specifying information such as content data C21 related to (similar to) the received content data C10 (for example, the same genre or the same artist) or the broadcast source side of the received content data C1 (eg, content If content specification information such as content data C31 to be recommended by a data provider (producer or the like) is also registered in the content catalog information, it is possible to make the content catalog information more enriched for each user. Can continue.

  In addition, since the storage area allocated in the storage unit 12 for storing such content catalog information is limited, the control unit 11 has, for example, a reference number (for example, a preset number of registered content specifying information). , 1000) or more, content specific information or the like is deleted from the content catalog information in the order of registration, or a preset reference time (for example, 300 hours) has passed since registration in the content catalog information. Old content identification information is deleted.

  Here, the reference number or the reference time is configured to be set for each genre of the content data Cj, and the reference number or the reference time is changed according to the reproduction frequency of the content data for each genre. For example, it is possible to make the content catalog information suitable for the user's preference in which more content specifying information corresponding to the genre desired by each user is registered. In this case, the control unit 11 calculates the reproduction frequency of the content data for each genre of the content data Cj (for example, the reproduction time or the number of reproductions per month for each genre), and appropriately reproduces the reproduction frequency for each genre. The reference number or reference time for each genre is changed and set according to the content specification information corresponding to the genre for which the number of registered content specification information exceeds the reference number or the content catalog information. The content specifying information corresponding to the genre for which time has passed is deleted from the content catalog information.

  The node processing program may be downloaded from a predetermined server on the network 8, for example, or recorded on a recording medium such as a CD-ROM and read via the drive of the recording medium. You may be made to do.

[ 3. Operation of tree-type content broadcasting system SX2 ]
Next, the operation of the tree-type content broadcasting system SX2 according to the present embodiment will be described with reference to FIGS. FIG. 10 is a flowchart showing processing at the time of reception of the content data Cj in the control unit 11 of the node Nn. FIG. 11 is a flowchart showing the content specifying information deletion process in the control unit 11 of the node Nn. FIG. 12 is a flowchart showing processing when the content catalog information is used in the control unit 11 of the node Nn.

(Processing when receiving content data Cj)
First, with reference to FIG. 10, processing when content data Cj is received will be described. As a premise of this processing, it is assumed that a tree-type content broadcasting system SX2 as shown in FIG. 2 is formed.

  In the process shown in FIG. 10, a broadcast stream is received from a node Nn (upstream node Nn to which the self is directly connected) located in an upper layer, and the amount of data such as content data Cj included in the broadcast stream is a certain amount or more. The process starts when the data is stored in the buffer memory 13.

  When the processing shown in FIG. 10 is started, the control unit 11 starts measurement of reproduction time (time count) (step S1) and performs reproduction processing of the content data Cj (step S2). In such reproduction processing, the content data Cj stored in the buffer memory 13 is controlled to be transmitted to the decoder unit 15 via the bus 22. Accordingly, the content data Cj is decoded by the decoder unit 15 and reproduced and output via the audio processing unit 18 and the speaker 19.

  Next, the control unit 11 acquires content specifying information included in the content specifying information packet C related to the content data Cj being received from the buffer memory 13, and the content specifying information is stored in the storage unit 12. It is determined whether or not it is registered in the catalog information (step S3). If it is not registered (step S3: NO), the process proceeds to step S4, and if it is registered (step S3: YES). The process proceeds to step S5.

  As described above, since the content specifying information packet C is inserted into the broadcast stream at a predetermined interval (for example, every 10 minutes), the node Nn is displayed during the broadcast of the content data Cj. Even if the user participates in the tree-type content broadcast system SX2 related to the broadcast channel, the content specifying information of the content data Cj being broadcast can be acquired.

  In step S4, the control unit 11 determines whether or not the measured reproduction time is equal to or longer than a predetermined time (for example, 20 minutes), and if not longer than the predetermined time (step S4: NO). When the process proceeds to step S5 and the predetermined time or more is reached (step S4: YES), the process proceeds to step S7.

  Here, since the content specifying information packet C is inserted into the broadcast stream at a predetermined interval (for example, every 10 minutes), the reproduction time becomes longer than the predetermined time (for example, 20 minutes) in step S4. Instead of determining whether or not the content specifying information packet C having the same content specifying information has been received n times (for example, twice) or more, it is determined whether it has been received, for example, twice or more. If it is received, the process may move to step S7.

  The transfer processing of the content data Cj in step S5 is performed when the lower layer node Nn is connected to itself (it is skipped when not connected), and the broadcast having a packet such as the received content data Cj is performed. The stream is transferred to the lower layer node Nn.

  Next, the control unit 11 determines whether or not to end the reproduction of the content data Cj (step S6). If the reproduction does not end (that is, the reproduction continues) (step S6: NO), the control unit 11 proceeds to step S2. Return and repeat the same process as above. On the other hand, when the reproduction ends (step S6: YES), the process ends. Note that whether or not the playback ends is, for example, whether or not there is a playback end instruction from the user via the input unit 21, whether or not the broadcast channel is switched (thus leaving the tree), Alternatively, the determination is made based on whether or not the broadcast of the content data Cj from the upper layer node Nn has ended.

  On the other hand, in step S7, the control unit 11 registers the acquired content specifying information, the registration number, and the registration date in the content catalog information. Thereby, the content catalog information of the content data Cj is created.

  In this processing example, it is assumed that the content specifying information includes at least information indicating a content name, a content ID, and a genre.

  Next, the control unit 11 adds, for example, “2” to the overflow limit value (the overflow limit value corresponding to the corresponding genre) of the corresponding genre of the content data Cj in which the content specifying information is registered (the value to be added is It is a reflection degree of the user's palatability and acts in the direction in which the difference due to palatability increases, and can take any value) (step S8).

  Here, the overflow limit value is an example of the reference number described above, and is preset for each genre and stored in the storage unit 12. For example, if the corresponding genre of the content data Cj in which the content specifying information is registered is “animation”, “2” is added to the overflow limit value corresponding to the genre of the animation and the limit value is changed and set. .

  Next, the control unit 11 determines whether or not the overflow limit value of the corresponding genre is larger than, for example, “100” (this value is not limited to this and can take any value) ( If it is greater than “100” (step S9: YES), the process proceeds to step S10, and if it is “100” or less (step S9: NO), the process proceeds to step S5.

  In step S10, the control unit 11 sets the overflow limit value of the corresponding genre to “100”, and then the oldest content specifying information in the corresponding genre (content specifying information with the oldest registration date). The selected content specifying information, its registration number and registration date are deleted from the content catalog information (step S11), and the process proceeds to step S5. With this process, the content specifying information is deleted from the corresponding genre in ascending order of registration.

  In step S11, the content specifying information that has passed a reference time (for example, 300 hours) after being registered in the content catalog information is selected, and the selected content specifying information and the like are deleted from the content catalog information. You may do it.

  The process shown in FIG. 10 is started every time the received content data Cj changes (at this time, the value of the reproduction time (time count) measured last time is reset to “0”). .

  In addition to the content specifying information of the content data Cj, the content specifying information packet C of the content data Cj being received includes, for example, content specifying information (at least) of other content data Cj broadcast on the broadcast channel. The content ID) is also included in, for example, the content input server SA1 or the highest node Nn, and in step S7, the content specifying information (at least the content ID), the registration number, and the registration date are registered in the content catalog. You may comprise so that it may register in information. For content specifying information (for example, content ID or content name) of other content data Cj broadcasted on the broadcast channel, each node Nn acquires, for example, the broadcast schedule table for that day, and the broadcast schedule table The content ID or content name acquired from the ID, the registration number, and the registration date and time may be registered in the content catalog information.

  In addition to the content specifying information of the content data Cj, the content specifying information packet C related to the content data Cj being received is related (similar) to the content data Cj (for example, of the same genre or the same artist). ) The content specifying information (at least the content ID) of the content data Cj is also configured to be included in, for example, the content input server SA1 or the highest node Nn. In step S7, the content specifying information (at least the content ID), If the registration number and the registration date are registered in the content catalog information, the content catalog information can be made more fulfilling to the user's preference.

  Furthermore, in addition to the content specifying information of the content data Cj, the content specifying of the content data Cj to be recommended on the broadcast side of the content data Cj is included in the content specifying information packet C related to the content data Cj being received. Information (at least content ID) is also included in the broadcast source, and in step S7, the content specifying information (at least content ID), its registration number, and registration date and time are registered in the content catalog information. If it is configured, it is possible to make the content catalog information complete, and it is possible to ensure an intentional audience rating on the broadcast source side, and content specifying information of content data Cj to be recommended in the content catalog information Registration fee (e.g. Content data Cj provider consideration paid from (producer, etc.) to the operator of the system SX2) can be set.

(Deleting content specific information)
Next, the content specifying information deletion process will be described with reference to FIG.

  The process shown in FIG. 11 is started at a predetermined cycle (subtraction cycle, for example, every week).

  When the process shown in FIG. 11 is started, the control unit 11 selects one genre among a plurality of genres (step S21), and subtracts, for example, “1” from the overflow limit value of the selected genre (note that The value to be subtracted is the degree of preference reflection, and acts in a direction in which the difference due to preference decreases, and can take any value) (step S22).

  Next, the control unit 11 determines whether or not the subtracted overflow limit value is, for example, “10” (this value is not limited to this and can take any value) or more. (Step S23) When the overflow limit value is “10” or more (step S23: YES), the process proceeds to step S25, and when the overflow limit value is not “10” or more (step S23: NO). ), The process proceeds to step S24.

  In step S24, the control unit 11 sets the overflow limit value of the selected genre to “10”, and proceeds to step S25.

  On the other hand, in step S25, the control unit 11 determines whether or not the number of registered content specifying information corresponding to the selected genre (the number registered in the content catalog information) is equal to or less than the overflow limit value of the genre. If it is not less than or equal to the overflow limit value (step S25: NO), the oldest content specifying information (the content specifying information with the oldest registration date) is selected from the genre, and the selected content specifying information is selected. The registration number and registration date are deleted from the content catalog information (step S26), and the process proceeds to step S27. On the other hand, when the registration number of the content specifying information is equal to or less than the overflow limit value (step S25: YES), the process proceeds to step S27.

  In step S26, the content specifying information that has passed a reference time (for example, 300 hours) after being registered in the content catalog information is selected, and the selected content specifying information or the like is deleted from the content catalog information. You may do it.

  In step S27, it is determined whether all genres have been selected in step S21. If all genres have not been selected (step S27: NO), the process returns to step S21, and genres that have not yet been selected are selected. A process similar to the above is performed. If all genres are selected (step S27: YES), the process ends. Thus, the overflow limit value for all genres is adjusted.

  If the value added in step S8 shown in FIG. 10 described above is increased, the increase rate of the overflow limit value every time the content specifying information is registered in the content catalog information is increased. While the allowable registration number of the content identification information of Cj increases and tends to approach the upper limit, increasing the value to be subtracted in step S22 shown in FIG. 11 increases the decrease rate of the overflow limit value for each subtraction period. The allowable registration number of the content specifying information of the content data Cj of the low genre decreases, and it becomes easy to approach the lower limit. Accordingly, the overflow limit value for each genre can be changed according to the reproduction frequency for each genre. Further, as described above, by making the value added in step S8 shown in FIG. 10 larger than the value subtracted in step S22 shown in FIG. The overflow limit value can be changed.

(Processing when using content catalog information)
Next, with reference to FIG. 12, a process when using the content catalog information will be described.

  The process shown in FIG. 12 is started when there is a content catalog display instruction from the user via the input unit 21.

  When the processing shown in FIG. 12 is started, for example, the control unit 11 of the node N1 acquires (reads) content catalog information from the storage unit 12, and all items are not registered in the content catalog information ( It is determined whether there is content specifying information (there is insufficient information) (step S31), and if there is content specifying information in which all items are not registered (for example, although the content ID is registered, the attribute information If all or part of the content is not registered (that is, if the content specifying information packet C contains only the content ID or the like) (step S31: YES), the process proceeds to step S32, and all items are stored. If there is no unregistered content specifying information (step S31: NO), the process proceeds to step S35.

  In step S32, the control unit 11 connects to the catalog management server SA2 via the network 8 in accordance with the IP address of the catalog management server SA2 and the like. For example, the content is included in the content specifying information in which all the items are not registered. Insufficient information request information including an ID or a content name and indicating a request for insufficient information in the content specifying information is transmitted to the catalog management server SA2. On the other hand, the catalog management server SA2 acquires the shortage information indicated in the shortage information request information from the content specifying information corresponding to, for example, the content ID or the content name included in the shortage information request information. And the content ID and the like are returned to the node Nn that has transmitted the shortage information request information.

  Each node Nn obtains the shortage information of the content specifying information from the catalog management server SA2, and in addition to the node Nn storing the content specifying information (for example, content data Cj corresponding to the content specifying information) May be obtained from the highest node Nn that broadcasts the above or the content holding node that stores the content data Cj.

  Then, when the control unit 11 of the node Nn receives the transmitted shortage information, content ID, and the like (step S33), the control unit 11 converts the shortage information corresponding to the received content ID and the like into content catalog information. Built in (step S34), the process proceeds to step S35.

  In step S <b> 35, the control unit 11 displays a content catalog as shown in FIG. 7 on the display unit 16 based on the content catalog information. As a result, the content specifying information registered in the content catalog information is presented to the user. As described above, when the content catalog is displayed (opened), the shortage information is fetched from the catalog management server SA2, but it is unlikely that each user will display the content catalog at the same time. Access concentration to SA2 can be avoided.

  In the content acquisition process shown in step S36, when the user specifies content specifying information (for example, a content name) via the input unit 21 on the content catalog displayed in this way, the control unit 11 accepts the specification, The designated content ID is acquired, and as described above, the content location inquiry message including the content ID is transmitted toward the root node. Thereby, for example, the node N1 participating in the content distributed storage system SX1 obtains the index information of the content holding node, connects to the content holding node, and acquires the content data Cj corresponding to the specified content ID. Then, it is reproduced according to the user's instruction.

  As described above, according to the above embodiment, the content catalog information used in the content distributed storage system SX1 is created based on the content data Cj broadcasted in the tree-type content broadcast system SX2. The node Nn can create its own content catalog information and suppress the distribution burden of a specific device such as the catalog management server SA2 (for example, the catalog management server SA2 does not need to distribute the content catalog information to all the nodes Nn). be able to. Furthermore, the content specifying information to be registered in the content catalog information is determined by the selection of the broadcast channel by the user and the reproduction time of the content data Cj being broadcast, so that unique content catalog information that meets the user's preference is created. It is possible to reduce the data amount of the content catalog information (that is, it is not necessary to register content specifying information of all content data Cj that can be acquired in the content distributed storage system SX1).

  Further, each node Nn can download the content data Cj broadcasted by the tree type content broadcasting system SX2 for purchase from the content distributed storage system SX1 using the content catalog information, so that it is broadcast by the tree type content broadcasting system SX2. It is not necessary to leave the content data Cj in the buffer memory 13 (cache it) and purchase it later (for example, store it in HD). 13 (for example, a long ring buffer memory) becomes unnecessary.

  The content distributed storage system SX1 in the above embodiment has been described on the assumption that it is formed by an algorithm using DHT, but the present invention is not limited to this.

It is a figure which shows an example of the connection aspect of each node apparatus in the communication system which concerns on this embodiment. It is a conceptual diagram of a content distributed storage system and a tree-type content broadcasting system. It is a figure which shows an example of the routing table using DHT which node N2 hold | maintains. It is a conceptual diagram which shows an example of ID space of DHT. It is the conceptual diagram which showed an example of the flow of the content location inquiry (search) message sent from the user node in ID space of DHT. It is a figure which shows an example of the information regarding the content data registered into the content catalog information in a certain node. It is a conceptual diagram which shows an example of the display form transition of the music catalog in a certain node. It is a figure which shows a mode that the broadcast stream containing content data Cj is broadcast in the tree type content broadcast system SX2. It is a figure which shows the example of an outline structure of the node Nn. It is a flowchart which shows the process at the time of reception of the content data Cj in the control part 11 of the node Nn. It is a flowchart which shows the deletion process of the content specific information in the control part 11 of the node Nn. It is a flowchart which shows the process at the time of utilization of the content catalog information in the control part 11 of the node Nn.

Explanation of symbols

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 Sound Processing Unit 18 Speaker 20 Communication Unit 21 Input Unit 22 Bus Nn Node SA1 Content Input Server SA2 Catalog Management Server SA3 Connection Mode management server S Communication system SX1 Content distributed storage system SX2 Tree-type content broadcasting system

Claims (15)

A tree-type content broadcasting system formed by a plurality of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies with the broadcasting device as the highest level. Content data broadcast by the node device in the tree-type content broadcasting system in which the node device in the upper layer is sequentially transferred from the node device in the upper layer to the node device in the lower layer,
Content receiving means for receiving the broadcasted content data;
Catalog creating means for creating content catalog information in which content specifying information for specifying at least the received content data is registered;
A node device comprising: The node device according to claim 1,
Presenting means for presenting the content specifying information registered in the content catalog information to a user;
Accepting means for accepting designation of any of the content specifying information from the user;
Content acquisition means for acquiring content data corresponding to the specified content identification information;
With
The content acquisition unit is a node device in a content distributed storage system in which a plurality of the content data is distributed and stored in a plurality of node devices, the node storing content data corresponding to the specified content specifying information A node device, wherein the content data is acquired from the device. The node device according to claim 1 or 2,
Reproducing means for reproducing the received content data;
Reproduction time measuring means for measuring the reproduction time of the content data related to the reproduction;
Further comprising
The node device characterized in that the catalog creating means registers content specifying information for specifying content data whose measured reproduction time is a predetermined time or more in the content catalog information. The node device according to claim 1 or 2,
In the tree-type content broadcasting system, for each of a plurality of broadcast channels, the plurality of node devices are connected in a tree shape through communication means while forming a plurality of hierarchies, and different content data is broadcast. There,
Reproducing means for reproducing the received content data;
Measuring means for measuring the reproduction time of the content data related to the reproduction for each channel;
Further comprising
The node device characterized in that the catalog creating means registers content specifying information for specifying content data broadcast on a broadcast channel whose measured reproduction time is a predetermined time or more in the content catalog information. . In the node apparatus as described in any one of Claims 1 thru | or 4,
The node device characterized in that the catalog creating means registers content specifying information for specifying content data related to the received content data in the content catalog information. In the node apparatus as described in any one of Claims 1 thru | or 4,
The node device characterized in that the catalog creating means registers content specifying information for specifying content data to be recommended on the broadcast side of the content data in the content catalog information. In the node apparatus as described in any one of Claims 1 thru | or 6,
The content specifying information is included at a predetermined interval in the broadcast stream of the content data,
The node device characterized in that the catalog creating means acquires the content specifying information to be registered in the content catalog information from the broadcast stream. In the node apparatus as described in any one of Claims 1 thru | or 6,
The node device characterized in that the catalog creating means acquires the content specifying information to be registered in the content catalog information from the broadcasting device. In the node apparatus as described in any one of Claims 1 thru | or 7,
A node device, further comprising: a specific information deleting unit that deletes from the content catalog information the content specific information for which a reference time has elapsed since being registered in the content catalog information. In the node apparatus as described in any one of Claims 1 thru | or 7,
When the registration number of the content specific information registered in the content catalog information exceeds a reference number, the information processing apparatus further comprises specific information deleting means for deleting the content specific information from the content catalog information in order of old registration. Feature node equipment. The node device according to claim 9, wherein
Reference time setting means for setting the reference time for each type of content data;
Reproducing means for reproducing the received content data;
Reproduction frequency calculating means for calculating the reproduction frequency of the content data for each type of the content data;
Further comprising
The reference time setting means changes the reference time for each type according to the reproduction frequency for each type of the content data,
The node device characterized in that the specific information deleting means deletes the content specific information corresponding to the type for which the reference time has elapsed since being registered in the content catalog information from the content catalog information. The node device according to claim 10, wherein
Reference number setting means for setting the reference number for each type of the content data;
Reproducing means for reproducing the received content data;
Reproduction frequency calculating means for calculating the reproduction frequency of the content data for each type of the content data;
Further comprising
The reference number setting means changes the reference number for each type according to the reproduction frequency for each type of the content data,
The node device characterized in that the specific information deleting means deletes the content specific information corresponding to the type whose registered number of content specific information exceeds a reference number from the content catalog information.   A node processing program for causing a computer to function as the node device according to claim 1. A tree-type content broadcasting system formed by a plurality of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies with the broadcasting device as the highest level. Is a tree-type content broadcasting system in which the content data broadcast by is sequentially transferred from the node device in the upper layer to the node device in the lower layer,
The node device is
Content receiving means for receiving the broadcasted content data;
Catalog creating means for creating content catalog information in which content specifying information for specifying at least the received content data is registered;
A tree-type content broadcasting system comprising: A tree-type content broadcasting system formed by a plurality of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies with the broadcasting device as the highest level. Content catalog information creation method in a tree-type content broadcasting system in which the content data broadcasted by is sequentially transferred from the node device in the upper layer to the node device in the lower layer,
The node device is
Receiving the broadcast content data;
Creating content catalog information in which content specifying information for specifying at least the received content data is registered;
A content catalog information creating method comprising:

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