JP4635966B2 - CONTENT DISTRIBUTION SYSTEM, CONTENT DISTRIBUTION METHOD, TERMINAL DEVICE IN CONTENT DISTRIBUTION SYSTEM, AND PROGRAM THEREOF - Google Patents

Description

  The present invention relates to content data distribution technology. Specifically, a plurality of terminal devices are logically connected in a multilayered manner with a content distribution device at the top for each channel, and content data streamed from the content distribution device is sequentially layered for each channel by the relay function of the terminal device In particular, the present invention relates to a content distribution system, a content distribution method, a terminal device in a content distribution system, and a program thereof that are relayed downstream of each other and can reproduce content data by a plurality of terminal devices.

  2. Description of the Related Art In recent years, content distribution services that perform streaming distribution of content data (hereinafter referred to as “content data”) such as music, movies, and talk programs have been started via networks such as the Internet. Here, the streaming distribution is a distribution method for distributing content data in a streaming format that can be stream-received by a client terminal device (hereinafter simply referred to as “terminal device”). You can play while receiving. Further, as a streaming distribution form, there are a broadcast format in which a distribution time of content data is determined and an on-demand format in which streaming distribution is performed to individual terminal devices in response to a request from the terminal device.

  Conventionally, a content distribution service in a broadcast format has been mainly used to directly distribute content from a single content distribution device to a plurality of terminal devices.

  However, with the enhancement of content distribution services and the increase in the number of terminal devices connected to the network, the number of terminal devices that request content data distribution from the content distribution devices increases, and the load on the content distribution devices increases. In addition, the concentration of traffic in the network has had a serious impact.

  In order to avoid such an increase in load and traffic on the content distribution device, a technology for distributing the load by placing a plurality of servers such as mirror servers and caches in the network in addition to the original distribution server has been put into practical use. However, a plurality of servers for distributing contents are required, and the cost of facilities increases.

  Therefore, a content distribution system has been proposed that can reduce load and traffic concentration without increasing the number of content distribution devices by relaying content data between terminal devices, that is, using a P2P communication mode.

  In this content distribution system, a plurality of terminal devices are logically connected in multiple layers in a tree-like hierarchical structure with the content distribution device at the top, and content data is sequentially distributed from the content distribution device to downstream terminal devices.

  That is, the content data distributed from the content distribution device is distributed to the terminal device located in the highest layer (first layer), and the terminal device located in the highest layer receives the content data distributed from the content distribution device. Relaying is performed to the terminal device located in the second hierarchy, and this content data is relayed to the terminal device located in the lowest layer.

  Usually, in such a content distribution system, a connection management device for logically connecting a plurality of terminal devices in a tree-like hierarchical structure is arranged on a network.

  The connection management device has a function of managing the connection state of the terminal devices in the hierarchical structure of the content distribution system, and forms a hierarchical structure when receiving a participation request from a terminal device not participating in the hierarchical structure. One of the plurality of terminal devices is selected and notified to the terminal device that made the participation request.

  The terminal device that has received this notification can participate in the content distribution system by making a connection request to the connection destination candidate that has been introduced by the connection management device. It can be received via an upstream terminal device.

  By the way, in a content distribution system in a broadcast format, when content data is streamed and distributed via a plurality of broadcast channels (hereinafter also simply referred to as “channels”), a tree-like hierarchical structure with the content distribution device at the apex is provided for each channel. Will be composed.

  Therefore, when the user of the terminal device performs an operation of switching channels in order to view content data of a channel different from the channel being viewed, a tree different from the tree-like hierarchical structure corresponding to the channel being viewed Will participate in the hierarchical structure.

  However, when the user of the terminal device switches the viewing channel, it takes a lot of time to participate in the tree-like hierarchical structure of the switching destination channel.

  That is, when the user performs an operation to switch channels, the terminal device performs processing for having the connection management device introduce other terminal devices that are connection destinations in the new hierarchical structure, or NAT (Network Address Translation). It is necessary to perform processes that exceed the limit, and it is not possible to participate in a new hierarchical structure until these processes are completed, and even if the user performs an operation to switch channels, the connection destination cannot be switched immediately. .

As a method of dealing with the problem of such channel switching (hereinafter also referred to as “zapping”) by the user, summary data (content data for countermeasures) related to other channels is superimposed and distributed on the content data. There has been proposed a content distribution system that uses an information browsing method that shortens the time from a channel switching operation by a user until a terminal device connects to another new terminal device (see, for example, Patent Document 1).
JP 2003-324711 A

  However, since the terminal device simultaneously receives the content data of the channel being viewed and the content data of another channel for countermeasures against zapping, the terminal device communicates with other devices via the network. May not be able to secure a sufficient communication speed with the other device.

  That is, when participating in a content distribution system having a tree-like hierarchical structure, even content data that has not been viewed will be received, resulting in narrowing the communication bandwidth (bandwidth) in the terminal device, When other communication is performed, the communication speed cannot be sufficient, and depending on the case, there is a possibility that communication cannot be performed.

  The present invention has been made in view of the above inconveniences, and even when content data of a channel that is not viewed is received as a countermeasure against zapping, the terminal device 2 can be connected to other communications. An object of the present invention is to provide a content distribution system and method capable of suppressing the influence.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a plurality of terminal devices are multi-layered in a hierarchical structure for each channel on a network, with a content distribution device streaming distribution of content data through a plurality of channels, respectively. The content data managed by the connection management device so as to be logically connected to each other and transmitted from the content distribution device is relayed sequentially from the upstream terminal device to the downstream terminal device of the hierarchical structure for each channel. Another terminal device that holds the content data based on a content data download request from one terminal device distributes the content data between the first distribution form that is distributed by function and the plurality of terminal devices Content having the second distribution form In the communication system, the content distribution device includes distribution means for streaming distribution of the content data via the network, and the connection management device connects the terminal devices that configure the hierarchical structure for each channel. A connection state information storage unit that stores state information; and a connection destination candidate is selected from the connection state information stored in the connection state information storage unit when a connection destination introduction request is received from the terminal device via the network And a notification means for notifying the connection destination candidate selected by the connection destination candidate selection means to the terminal device that has transmitted the connection destination introduction request via the network. The terminal device includes channel selection means for selecting the channel and the channel selection means. The connection destination introduction request for the selected channel and the connection destination introduction request for a channel having a predetermined relationship with the channel are transmitted to the connection management device, and then notified from the connection management device for each channel. Connecting means for connecting to each of the connection destination candidates and participating in the first distribution form via a plurality of channels, and streaming reception for streaming receiving the content data for each channel from the connection destination candidates connected via the network Means, a ring buffer area for temporarily storing the content data received by the streaming receiving means for each channel, and the content data of the channel selected by the channel selection means among the content data stored in the ring buffer area A streaming playback means for streaming playback, a streaming relay means for streaming transfer of the received content data to the terminal device that has made the relay request when receiving a relay request for the content data from another terminal device, (2) a download operation detecting means for detecting an operation of a download request for content data according to a distribution form; and when the download request operation is detected by the download operation detecting means, the connection means among the channels connected by the connecting means A disconnecting unit that disconnects the connection destination candidate with respect to a channel having a predetermined relationship with the channel selected by the channel selecting unit; and when the download request detecting unit detects the download request operation, Based on the identification information acquisition means for acquiring the identification information of the content data and the identification information of the content data acquired by the identification information acquisition means in order to acquire the content data requested for download in the second distribution form Download processing means for downloading the content data requested for download from the terminal device of the second distribution form, content data storage means for storing the content data downloaded by the download processing means, and the download processing means. When the download of the content data requested to be downloaded is completed, the connection destination introduction request regarding the channel disconnected by the disconnection unit is transmitted to the connection management device, and then the connection notified from the connection management device is transmitted. And a content distribution system and a re-connection means for reconnecting to previously candidate.

  Further, in the invention described in claim 2, in the invention described in claim 1, the terminal device determines whether or not the entire content data requested to be downloaded is stored in the ring buffer area. When the determination means determines that the entire content data requested to be downloaded is stored in the ring buffer area, the content data is not downloaded according to the second distribution form, but is stored in the ring buffer area. Content data storage control means for storing the stored content data in the content data storage means, and the determination means determines that the entire content data requested for download is stored in the ring buffer area. Then, the cutting means is in the connected state. The connection with the connection destination candidate of the channel to be connected is not cut off.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the terminal device determines whether or not the content data requested to be downloaded is stored in the content data storage means. Determining means for determining, and when the determining means determines that the content data requested for download is stored in the content data storage means, the disconnecting means is configured to connect the connection destination of the channel in the connected state. Connection with a candidate is not cut off, and the download processing means does not download the content data according to the second distribution form.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, content data distributed in the second distribution form is part of the plurality of terminal devices. Content input means to be transmitted to, identification information list storage means for storing an identification information list including a plurality of identification information of content data to be streamed by the content distribution device, and the identification information list stored in the identification information list storage means A content input device having an identification information list transmitting means for transmitting to the plurality of terminal devices, the terminal device having an identification information list receiving means for receiving an identification information list transmitted from the content input device. The identification information acquisition means is the identification information list received by the identification information list reception means. The identification information of the content data requested to be downloaded is acquired. The invention according to claim 5 is the invention according to claim 4, wherein the identification information list storage means is the content distribution device. An identification information list including identification information of content data other than content data to be distributed by streaming is stored.

  The invention according to claim 6 is the identification information according to any one of claims 1 to 3, wherein the content distribution device transmits identification information of content data to be streamed by the distribution means. The terminal device has identification information receiving means for receiving identification information of the content data transmitted from the content distribution device, and the identification information acquisition means is received by the identification information receiving means. The identification information of the content data requested to be downloaded is obtained from the identification information of the content data.

  According to a seventh aspect of the present invention, a plurality of terminal devices are logically connected in multiple layers in a hierarchical structure for each channel on a network with a content distribution device that performs streaming distribution of content data on a plurality of channels as a vertex. The content data managed by the connection management device and transmitted from the content distribution device is stream-distributed by the relay function of the terminal device sequentially from the upstream terminal device to the downstream terminal device of the hierarchical structure for each channel. A first distribution form, and a second distribution form in which another terminal apparatus holding the content data distributes the content data based on a content data download request from one terminal apparatus, among the plurality of terminal apparatuses. In a content distribution system having A channel selection unit for selecting the channel; the connection destination introduction request for the channel selected by the channel selection unit; and the connection destination introduction request for a channel having a predetermined relationship with the channel. Connecting to the connection management device, and then connecting to the connection destination candidates notified for each channel from the connection management device to join the first distribution mode in a plurality of channels, and Streaming receiving means for streaming receiving the content data from the connection destination candidates connected via a network for each channel; and a ring buffer area for temporarily storing content data received by the streaming receiving means for each channel; The ring buffer Receiving a relay request for streaming the content data of the channel selected by the channel selection means from the content data stored in the area and the relay request for the content data from the other terminal device. A streaming relay unit for streaming transfer of the received content data to the terminal device; a download operation detection unit for detecting an operation of a download request for content data according to the second distribution form; and When an operation is detected, among the channels connected by the connecting means, the connection with the connection destination candidate relating to the channel having a predetermined relationship with the channel selected by the channel selecting means When the download request operation is detected by the cutting means for cutting the download data and the download operation detection means, the identification information of the content data is acquired in order to acquire the content data requested for download in the second distribution form. Identification information acquisition means for downloading, download processing means for downloading the content data requested for download from the terminal device in the second distribution form, based on the identification information of the content data acquired by the identification information acquisition means, Content data storage means for storing the content data downloaded by the download processing means, and when the download processing means completes downloading of the content data requested for download, the channel cut by the cutting means Transmitting the connection destination introduction request regarding Le to the connection management apparatus, then the re-connection means for reconnecting the notified the connection destination candidate from the connection management apparatus, a terminal device with a capital.

  The invention according to claim 8 is the determination means according to claim 7, wherein the determination means determines whether or not the entire content data requested to be downloaded is stored in the ring buffer area, and the determination means. If the content data requested to be downloaded is determined to be stored in the ring buffer area, the content stored in the ring buffer area is not downloaded according to the second distribution form. Content data storage control means for storing data in the content data storage means, and when the determination means determines that the entire content data requested to be downloaded is stored in the ring buffer area, the cutting means Of the channel in the connected state Characterized in that it does not disconnect the serial connection destination candidate.

  Further, the invention according to claim 9 is the invention according to claim 7 or claim 8, wherein the determination means for determining whether or not the content data requested to be downloaded is stored in the content data storage means. And the determining means determines that the download requested content data is stored in the content data storage means, the disconnecting means establishes a connection with the connection destination candidate of the channel in the connected state. The download processing means does not download the content data according to the second distribution form.

  The invention according to claim 10 is the invention according to any one of claims 7 to 9, wherein the content data distributed in the second distribution form is a part of the plurality of terminal devices. Identification information list receiving means for receiving the identification information list from a content input device that transmits to the plurality of terminal devices an identification information list that includes a plurality of identification information of content data that is transmitted to the device and streamed by the content distribution device The identification information acquisition unit acquires the identification information of the content data requested to be downloaded from the identification information list received by the identification information list reception unit.

  The invention according to claim 11 is the invention according to claim 10, wherein the identification information list includes identification information of content data other than the content data to be streamed by the content distribution device. .

  The invention according to claim 12 is the invention according to any one of claims 7 to 9, further comprising identification information receiving means for receiving identification information of the content data transmitted from the content distribution device. And the identification information acquiring means acquires the identification information of the content data requested to be downloaded from the identification information of the content data received by the identification information receiving means.

  The invention described in claim 13 is a case where there are a plurality of channels having a predetermined relationship with the channel selected by the channel selection means in the invention described in any one of claims 7-12. When the download request detection unit detects the download request operation, the channels related to all the channels having a predetermined relationship with the channel selected by the channel selection unit among the channels connected by the connection unit. The connection with the connection destination candidate is cut off.

  The invention according to claim 14 is the invention according to any one of claims 7 to 13, wherein the channel having the predetermined relationship is a channel adjacent to the channel number selected by the channel selection means. It is a channel having a number.

  The invention according to claim 15 is a program for causing a computer to function as each means in the terminal device according to any one of claims 7 to 14.

  Further, in the invention described in claim 16, a plurality of terminal devices are logically connected in multiple layers in a hierarchical structure for each channel on a network with a content distribution device that performs streaming distribution of content data through a plurality of channels as a vertex. The content data managed by the connection management device and transmitted from the content distribution device is stream-distributed by the relay function of the terminal device sequentially from the upstream terminal device to the downstream terminal device of the hierarchical structure for each channel. A first distribution form, and a second distribution form in which another terminal apparatus holding the content data distributes the content data based on a content data download request from one terminal apparatus, among the plurality of terminal apparatuses. Content distribution system with In the content distribution method, the distribution device performs streaming distribution of the content data, and the connection management device stores connection state information of the terminal devices constituting the hierarchical structure in a connection state information storage unit. A connection destination introduction request for the channel selected by the channel selection means for selecting the channel by the terminal device and the connection destination introduction request for a channel having a predetermined relationship with the channel via the network. Transmitting to the connection management device, and when the connection management device receives the connection destination introduction request from the terminal device via the network, the connection status information stored in the connection status information storage means Selecting a connection destination candidate from: and the connection management device Notifying the selected connection destination candidate to the terminal device that has transmitted the connection destination introduction request via the network, and the connection destination for each channel notified from the connection management device by the terminal device Connecting to each candidate and participating in the first distribution form through a plurality of channels; and receiving the content data for each channel from the connection destination candidate connected via the network by the terminal device The terminal device temporarily storing the streaming-received content data in a ring buffer area for each channel; and the channel selection means of the content data stored in the ring buffer area by the terminal device Content data of the channel selected by Streaming the data, and when the terminal device receives the content data relay request from another terminal device, streaming the received content data to the terminal device that has made the relay request; When the terminal device detects an operation of downloading content data according to the second distribution form, the connection destination candidate for the channel having a predetermined relationship with the selected channel among the channels in the connection state Disconnecting the connection, and when the terminal device performs an operation of requesting download of content data in the second distribution form, the content data is acquired in order to acquire the content data requested for download in the second distribution form. Obtaining the identification information of A step of downloading the content data requested to be downloaded from the terminal device in the second distribution form based on the acquired identification information of the content data; and the terminal device is configured to download the downloaded content data as content. Storing in the data storage means, and when the terminal device completes the download of the requested content data, transmits the connection destination introduction request for the disconnected channel to the connection management device, and then the connection And a step of reconnecting to the connection destination candidate notified from the management device.

  According to the first, seventh, fifteenth and sixteenth aspects of the present invention, when content data is viewed in the broadcast form with the tree-type hierarchical structure as the first distribution form, there is a fixed relationship with the channel to be viewed as a countermeasure for zapping. When the content purchase is performed in the second distribution form such as grid connection after that, the zapping countermeasure channel is automatically withdrawn from the hierarchical structure, and the content purchase process in the second distribution form is completed. Since the network is automatically reconnected (rejoined) to the zapping countermeasure channel hierarchical structure, both the first distribution form and the second distribution form can be achieved even in an environment where the network bandwidth is severe. It is possible to provide a content distribution system or a terminal device thereof.

  According to the second and eighth aspects of the present invention, content data distributed in broadcast form is temporarily cached in the ring buffer area, and the purchased content data is stored in the ring buffer area. Sometimes, the content data stored in the ring buffer area can be purchased. Therefore, it is possible to shorten the content data purchase process compared to newly acquiring content data in the second distribution form. By increasing the capacity of the ring buffer area, it is possible to cache a large amount of content data distributed in broadcast form, so that the download time can be shortened for users who often download the content data after viewing it. Is big.

  According to the third and ninth aspects of the present invention, when the content data to be purchased is already stored in the content data storage means, the content data stored in the content data storage means can be purchased. Therefore, it is possible to shorten the content data purchase process compared to newly acquiring content data in the second distribution form. For example, when the terminal device is a content holding terminal device, when purchasing content data corresponding to the content holding terminal device, the content data stored in the terminal device can be used.

  According to the fourth and tenth aspects of the present invention, since the list of content data identification information necessary for downloading the content data in the second distribution form can be acquired from the content input device, It is not necessary to acquire identification information of content data to be downloaded to the content input device every time the download process is performed, the load on the network and the content input device can be reduced, and the download processing time can be shortened.

  According to the fifth and eleventh aspects of the present invention, the content input device can store an identification information list including identification information of content data other than the content data to be streamed by the content distribution device. Although it is not the content data directly distributed in the form, the content data related to them can be acquired in the second distribution form.

  Further, according to the inventions of claims 6 and 12, since the identification information of the content data necessary for downloading the content data in the second distribution form is transmitted from the content distribution device to the terminal device, the terminal device Since it is not necessary to request and acquire the identification information of the content data to be downloaded from the content input device or the like, the processing in the content input device can be reduced. The content data identification information may be included in the header of the content packet to be streamed and transmitted from the content distribution device.

  Further, according to the invention of claim 13, when there are a plurality of zapping countermeasure channels, it is withdrawn from all the zapping countermeasure channels, so it is possible to secure a larger communication band, and in the second distribution form Communication can be stabilized.

  According to the fourteenth aspect of the invention, since the zapping countermeasure channel is a channel having a channel number adjacent to the channel number of the viewing channel, the channel switching is performed by increasing or decreasing the channel number one by one. A terminal device having a channel switching interface can effectively take a countermeasure against zapping. Here, “increase / decrease the channel number by one” means, for example, when the channel being viewed is channel ch4 and the adjacent zapping countermeasure channels are channels ch1 and ch6, from channel ch4 to channel ch1 or from channel ch4. This means switching to channel ch6.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the invention will be described based on the drawings. The embodiment described below is an embodiment when the present invention is applied to a content distribution system in which information to be distributed is content data such as music data and video data.

[1. Content distribution system configuration]
FIG. 1 is a diagram illustrating a schematic configuration example of a content distribution system S according to the present embodiment. As in the physical connection form shown in FIG. 1, the content distribution device 1, the terminal devices 2a1, 2a2, 2b1 to 2b4, 2c1 to 2c8, the connection management device 3, the content input device 4, and the contact destination introduction constituting the content distribution system S The devices 5 are distributed on a network represented by the Internet. An apparatus not directly related to the content distribution system S is also connected to the network 6, but is omitted here. Further, in the case of showing any one of the terminal devices 2a1, 2a2, 2b1-2b4, 2c1-2c8 or all the terminal devices, it may be called the terminal device 2 for convenience.

The content distribution device 1, the terminal devices 2a1, 2a2, 2b1 to 2b4, 2c1 to 2c8, the connection management device 3, the content input device 4, and the contact introduction device 5 have unique serial numbers (information identifying each device). For example, a MAC address) and an IP (Internet Protocol) address (location information) are assigned, and these devices are connected to a network 6 as an example of the network via a router 10 or the like. That is, communication connection is possible by transmitting a packet including a header having the destination IP address of the destination device as the destination IP address and the source IP address as the source device IP address.
In the example shown in FIG. 1, the content distribution device 1, the connection management device 3, the content input device 4, and the contact destination introduction device 5 are independent devices, but the functions of these devices in one device. May be realized. In this case, the IP addresses of these devices are the same and are distinguished by port numbers and the like.

  The content distribution system according to the present embodiment is configured such that a plurality of terminal devices are layered for each channel on a network with a content distribution device that performs streaming distribution of content data on a plurality of broadcast channels (hereinafter simply referred to as “channels”) as a vertex. It is managed by the connection management device so that it is logically connected in multiple layers in the structure, and the content data transmitted from the content distribution device is sequentially transferred from the upstream terminal device to the downstream terminal device of the hierarchical structure for each channel by the relay function of the terminal device A first distribution form in which streaming distribution is performed, and a second distribution form in which another terminal apparatus that holds content data based on a request to download content data from one terminal apparatus distributes content data between a plurality of terminal apparatuses. And have.

  When the user of the terminal device views the content data from the content distribution device in the first distribution form, the terminal device is referred to as a viewing target channel (hereinafter referred to as “viewing channel”. Here, channels ch1 to ch1). Channels other than the viewing channel and having a predetermined relationship with the viewing channel (hereinafter referred to as “zapping countermeasure channel”). ) To participate in the hierarchical structure.

  Therefore, when a viewing channel switching operation (hereinafter referred to as “zapping”) is performed by the user of the terminal device, the content data of the new channel can be viewed from the channel switching operation by the user by the zapping countermeasure channel. Can be shortened.

  FIG. 2 schematically shows a state in which the terminal device 2X participates in the hierarchical structure of the viewing channel A and the hierarchical structure of the zapping countermeasure channel B in the first distribution form. In FIG. 2, the zapping countermeasure channel is one channel for convenience of explanation.

  When the user of the terminal device 2X performs an operation for acquiring content data in the second distribution form in a state where the terminal device 2X is connected to the viewing channel A and the zapping countermeasure channel B in this way, the terminal device 2X 3 disconnects the zapping countermeasure channel B and leaves the hierarchical structure of the zapping countermeasure channel B as shown in FIG.

  After that, as shown in FIG. 4, the terminal device 2X transmits a content search message, and acquires location information of the content holding terminal device 2Y from the root terminal device 2Z. Thereafter, the terminal device 2X makes a content data transmission request to the content holding terminal device 2Y, and acquires the content data in the second distribution form.

  When the reception of the content data in the second distribution form is completed, the terminal device 2X reconnects to the zapping countermeasure channel B that was withdrawn when acquiring the content data in the second distribution form, and rejoins the hierarchical structure of the zapping countermeasure channel B. Then, the state returns to the state shown in FIG.

  As described above, in the content distribution system S according to the present embodiment, when the user of the terminal device 2 views content data in the broadcast form based on the tree-type hierarchical structure that is the first distribution form, the channel to be viewed is constant. Participating in the hierarchical structure of anti-zapping channels that have a relationship, and then, when purchasing a content in the second distribution form such as grid connection, automatically leaves the hierarchical structure of the anti-zapping channel and purchases the content in the second distribution form Since the network automatically rejoins the hierarchical structure of the anti-zapping channel when the network is finished, the first distribution form and the second distribution form are implemented while taking countermeasures against zapping even in an environment where the network bandwidth is severe. Providing a content distribution system or a terminal device thereof Can.

  Hereinafter, the content distribution system in the present embodiment will be described more specifically with reference to the drawings.

[1.1. About the first distribution form]
As shown in FIG. 1, the first distribution form of the content distribution system S is that a plurality of terminal devices 2a1, 2a2, 2b1-2b4, 2c1-2c8 are logically connected in a tree-like hierarchical structure with the content distribution device 1 as a vertex. The content data is streamed and distributed from the content distribution device 1 to the downstream terminal device 2 by the relay function of the terminal device 2 sequentially from the upstream terminal device 2 of the tree-like hierarchical structure. This tree-like hierarchical structure is configured for each channel distributed by the content distribution apparatus 1.

  In the first distribution form of the content distribution system S, a plurality of terminal devices 2 are logically connected in multiple layers in a tree-like hierarchical structure with the content distribution device 1 as the apex (here, the 0th layer for convenience) for each channel. It is managed by the connection management device 3 as described above. In the present embodiment, a tree-like hierarchical structure is described. However, the present invention is not limited to this, and a plurality of terminal devices 2 may be logically connected in multiple layers in a chain-like hierarchical structure. The terminal devices 2a1 and 2a2 may be referred to as a terminal device 2a for convenience, the terminal devices 2b1 to 2b4 may be referred to as a terminal device 2b for convenience, and the terminal devices 2c1 to 2c8 may be referred to as a terminal device 2c for convenience.

  Here, the content data distribution operation in the first distribution mode will be briefly described with reference to FIG. FIG. 5 is an explanatory diagram of the distribution operation of the first distribution form in the content distribution system S.

  As shown in FIG. 5, content data that is stream-distributed by the content distribution device 1 in the first distribution form is input to the content distribution device 1 by the content input device 4. That is, the content data is transmitted from the content input device 4 to the content distribution device 1, received by the content distribution device 1, and held in the hard disk device.

  As shown in FIG. 5, the connection management device 3 is connected to the terminal device 2 that does not participate in the first distribution form in the content distribution system S, in other words, from the terminal device 2 that does not constitute any tree-like hierarchical structure of channels. Upon receiving the connection destination introduction request, based on the state of the tree-like hierarchical structure of the first distribution form, the connection destination candidate (content distribution device 1 or the content distribution device 1 or the terminal device 2 is connected as an upstream device for receiving streaming distribution) Terminal device 2) is selected. Then, the connection management device 3 notifies the terminal device 2 of the location information (such as the IP address and port number of the connection destination candidate) and the communication protocol of the connection destination candidate thus selected. The connection destination introduction request is transmitted from the terminal device 2 when switching to another channel or when the connection with the upstream device is disconnected.

  In the content distribution system S, when the communication protocol and the port number are already fixed, the port number and the communication protocol to the terminal device 2 need not be notified. Here, MMS (Microsoft Media Server) protocol, RTSP (Real Time Streaming Protocol), etc. are used as communication protocols. As the format of the content data, ASF (Advanced Streaming Format), WMA (Windows (registered trademark) Media Audio), WMV (Windows (registered trademark) Media Video), or the like is used.

  Upon receiving the location information of the connection destination candidate from the connection management device 3, the terminal device 2 requests the connection destination candidate to participate (connect) to the content distribution system S with the location information as a destination, and thereby the terminal device 2 is incorporated into the hierarchical structure in the first distribution form of the content distribution system S. That is, the terminal device 2 can receive the content data distributed from the content distribution device 1.

  In the first distribution form in the content distribution system S, the terminal devices 2 participate in each channel one after another in this way, and the plurality of terminal devices 2 are logically connected in a multi-layered tree structure with the content distribution device 1 as a vertex. Is done. Then, the content data distributed from the content distribution device 1 is sequentially relayed to the downstream terminal device 2 by the relay function of the terminal device 2 and streamed to the plurality of terminal devices 2.

  That is, as shown in FIG. 5, when content data is transmitted from the content distribution device 1 to the terminal devices 2a1, 2a2 (first-layer terminal devices) and the terminal devices 2a1, 2a2 receive the content data, the downstream terminal device The received content data is relayed sequentially to 2b1 to 2b4 (second layer terminal devices). When receiving the content data, the terminal devices 2b1 to 2b4 relay the received content data sequentially to the downstream terminal devices 2c1 to 2c8 (third layer terminal devices). In FIG. 5, only the hierarchical structure of one channel among a plurality of channels is shown for easy understanding.

  The terminal device 2 stores the location information of the terminal device 2 or the content distribution device 1 upstream of the position of the incorporated hierarchical structure and the location information of the terminal device 2 downstream of the location of the incorporated hierarchical structure. The content data is relayed based on the location information stored in this manner. Further, the content data to be distributed is divided into a plurality of packets and sequentially distributed, and the data thus divided and distributed is called a content packet.

  In this way, the content data distributed to the terminal device 2 is distributed to the terminal device 2 constituting the hierarchical structure for each channel. The distributed content data includes reproduction time information in addition to content data such as music and movies. Then, the plurality of terminal devices 2 that have received the content data perform the reproduction of the sequentially transmitted content data based on the reproduction time information.

  Here, the ring buffer area in the terminal device 2 will be described. FIG. 6 is a diagram conceptually illustrating a configuration in which content data is received using the ring buffer area in the terminal device 2 and is played back or relayed to the downstream terminal device 2. This ring buffer area is provided for each participating channel. In addition to the ring buffer area for the viewing channel, a ring buffer area for the zapping countermeasure channel is also provided.

  When the terminal device 2 participates in the first distribution form, the content data included in the received content packet is sequentially received by the stream receiver from the content receiver streamed from the upstream device of the hierarchical structure in the participating channel. Are temporarily stored in the ring buffer area. The content data temporarily stored in the ring buffer area is taken out of the ring buffer area and played by the player as the playback means of the terminal device 2 at the playback time.

  Here, as shown in FIG. 6, new content data is sequentially stored in the ring buffer area in the clockwise direction, and the oldest content data is rewritten to new content data. That is, if the point written in the ring buffer area by the stream receiver is A, the point A moves clockwise.

  Note that the ring buffer area in FIG. 6 is conceptually shown and is not actually ring-shaped, but the control unit of the terminal device 2 stores the oldest content stored in a predetermined address area in the storage area. This is realized by sequentially rewriting data with new content data.

  In addition, the playback time information is stored in the content data as described above, and the player has content data having playback time information matching the current time among the content data stored in the ring buffer area (here, FIG. 6). The content data of the middle B point) is taken out from the ring buffer area and sequentially reproduced. Note that the content data stored in the ring buffer area of the zapping countermeasure channel is not reproduced.

  With such a ring buffer area, content data loss that occurs intermittently depending on the state of the network 6 before the reproduction time is handled while accumulating content data before the reproduction time. In other words, the content distribution apparatus 1 distributes content data while ensuring a margin sufficient to perform packet loss compensation processing. Note that the packet loss compensation process is a process in which if a packet from the host device does not arrive after waiting for a certain period of time, a packet retransmission request is sent to the host device and the packet is transmitted again from the host device. In the loss compensation process, a series of processes must be performed as described above, and it takes a certain amount of time. Therefore, it is necessary to secure a margin as described above.

  Here, when two other terminal apparatuses 2 are connected downstream of the hierarchical structure, as shown in FIG. 6, the terminal apparatus 2 is provided with two stream transmitters. This stream transmitter stores the content data stored in the ring buffer area in the data area of the content packet every predetermined amount, generates a content packet, and transmits this content to the other terminal devices 2 connected downstream. Send packets sequentially.

  In the terminal device 2 in the first embodiment, the content data included in the content packet transmitted from the upstream device is extracted and stored in the ring buffer area. However, the content packet is stored in the ring buffer area as it is. It may be. In any case, the stream transmitter transmits to the downstream terminal device 2 a content packet in which the information on the transmission destination and transmission source of the content packet received by the stream receiver is replaced. The stream receiver corresponds to a later-described stream receiving unit, the player corresponds to a later-described stream reproducing unit, and the stream transmitter corresponds to a later-described stream relay unit.

  In this way, the terminal device 2 provides a ring buffer area for temporarily storing content data, thereby compensating for packet loss while pre-buffering the content packet, thereby reducing packet loss that occurs on the network 6 path. I try to avoid the impact.

  As described above, in the first distribution form of the content distribution system S, the content data transmitted from the content distribution device 1 is stream-distributed to the plurality of terminal devices 2, and the content is reproduced at the same time on the plurality of terminal devices 2. be able to. That is, the content distribution system S realizes streaming distribution in a broadcast format to a plurality of terminal devices 2 using P2P.

[1.2. About the second distribution form]
Next, with reference to FIG. 7, a schematic configuration and the like of the second distribution form in the content distribution system S will be described. FIG. 7 is a diagram illustrating a second distribution form in the content distribution system S according to the present embodiment. This second distribution form is a P2P grid type distribution system. In this embodiment, the second distribution form is distributed on the network by using a distributed hash table (hereinafter referred to as “DHT”). A distribution form in which content data is transmitted and received between a plurality of terminal devices 2 will be described as an example.

[1.2.1 Outline of DHT]
First, an algorithm using DHT according to the present embodiment will be described.

  In the second distribution form of the content distribution system S, when the terminal devices 2 exchange information with each other, they must know IP addresses as location information of each other.

  For example, in a system in which content is shared among a plurality of terminal devices, each terminal device 2 participating in the network 6 knows the IP addresses of all the terminal devices 2 participating in the network 6 with each other. However, when the number of terminals increases to tens of thousands and hundreds of thousands, it is not realistic to remember the IP addresses of all the terminal devices 2. Further, if the power supply of an arbitrary terminal device is frequently turned on or off, the IP address of the arbitrary terminal device stored in each terminal device 2 is frequently updated, which makes operation difficult.

  Therefore, one terminal device 2 stores only the IP addresses of some of the minimum necessary terminal devices 2 among all the terminal devices 2 participating in the network 6, and stores the IP addresses. For a terminal device 2 that is not connected, a system has been devised to deliver content by transferring information between the terminal devices 2.

  As an example of such a system, an overlay network as shown in FIG. 7 is constructed by an algorithm using DHT. That is, this overlay network is a network that forms a virtual link (logical connection) formed using the existing network 6, and is a P2P grid type distribution form.

  In this embodiment, it is premised on an overlay network constructed by an algorithm using DHT, and a terminal device 2 arranged on this overlay network is participating in the second distribution form of the content distribution system S. It is called device 2. The participation in the second distribution form of the content distribution system S is performed by the terminal device 2 that has not yet participated sending a participation request to the terminal device 2 that has already participated.

A unique number (unique number) is assigned to each terminal device 2 as a terminal ID that is an identification number of each terminal device 2 participating in the second distribution form of the content distribution system S. This number needs to have a number of bits that can accommodate the maximum number of operating terminal devices. For example, if a 128-bit number is used, 2 ¹²⁸ ≈340 × 10 ³⁶ terminal devices can be operated.

  More specifically, the terminal ID of each terminal device 2 is obtained by hashing a unique value for each terminal device 2 such as the IP address or manufacturing number of each terminal device 2 with a common hash function (hash algorithm). The obtained hash value is distributed and arranged in one ID space without deviation. Thus, the terminal ID obtained by hashing with a common hash function has a very low probability of having the same value if the IP address or the manufacturing number is different. Since the hash function is publicly known, detailed description thereof is omitted. In the present embodiment, a value obtained by hashing an IP address (global IP address) with a common hash function is used as a terminal ID.

  In addition, as shown in FIG. 7, content data distributed from one terminal device 2 to another terminal device 2 includes content in a plurality of terminal devices 2 participating in the second distribution form of the content distribution system S. Although distributed to the terminal device 2 by the input device 4, unique identification information (hereinafter referred to as “content ID”) for each content data is given to the content data.

  The content ID has the same length as the terminal ID (for example, 128 bits). For example, a keyword such as a content name (content title name) or content summary information (summary) determines the terminal ID. A terminal that is hashed by a hash function that is common to the time of acquisition (that is, placed in the same ID space as the hash value of the IP address of the terminal device 2) and that is closest to the hash value (for example, the higher-order digits match more) The terminal device 2 having the ID holds link information to the terminal device 2 that holds content data (hereinafter referred to as “content holding terminal device”), that is, an IP address that is location information of the content holding terminal device.

  The content holding terminal device is randomly determined by the content input device 4. That is, the content input device 4 randomly determines one or more terminal devices 2 that should hold the content data, and transmits the content data to the terminal device determined in this way. The terminal device that has received the content data from the content input device 4 functions as a content holding terminal device by holding the content data in the storage unit. Thereby, the content data is distributed and arranged on the content distribution system S without any bias.

  Note that even if the content data is different, it is assumed that the same keyword (for example, the name of the content) is used. In this case, the hash value is the same to avoid the same hash value. The keyword may be, for example, a combination of content name and copyright information (for example, performer name, director name, original author name, singer name, composer name, or songwriter name). In the present embodiment, the content names are not duplicated, and the content name is a keyword.

  As described above, since the terminal ID and the content ID assigned to each terminal device 2 and each content data are generated by a common hash function, as shown in FIG. 7, the terminal ID and the content ID are slightly biased on the same ring-shaped ID space. It can be thought of as being scattered and present. This figure shows a terminal ID and content ID assigned in 32 bits. In the figure, a round dot indicates a terminal ID, a square indicates a content ID, and the ID increases counterclockwise.

  Next, which terminal device 2 holds which content data is determined under a certain rule. In the present embodiment, the rule is that “the terminal device 2 that manages content data having a certain content ID is a terminal device 2 having a terminal ID close to that content ID”. Here, the definition of “close” does not exceed the content ID, and the difference between the content ID and the terminal ID is the smallest. However, in practice, the management of each content data is assigned to each terminal device 2. It is only necessary to be consistent when allocating. In the example shown in FIG. 7, based on this definition, the content IDa is managed by the terminal device 2 having a terminal ID close to the content IDa (hereinafter referred to as “terminal IDa”), and the content IDb is the content IDb. Managed by the terminal device 2 having a terminal ID close to IDb (hereinafter referred to as “terminal IDb”), and the content IDc has a terminal ID close to the content IDc (hereinafter referred to as “terminal IDc”). Managed by the device 2.

  Here, “management” does not mean that content data is held, but “knows which terminal device 2 holds the content data”. That is, in FIG. 7, the terminal device 2 having the terminal IDa knows which terminal device 2 holds the content data having the content IDa, and the terminal device 2 having the terminal IDb and the terminal having the terminal IDc. Similarly, the device 2 knows which terminal device 2 holds the content data having the content IDb and the content data having the content IDc.

  Thus, the terminal device 2 that knows which terminal device 2 holds certain content data is called the root terminal device of the content data. That is, the terminal device 2 having the terminal IDa is a root terminal device of content data having the content IDa, and the terminal device 2 having the terminal IDb is a root terminal device of content data having the content IDb, and the terminal IDc Is a root terminal device for content data having content IDc.

  Here, the content input device 4 has a function of distributing content data to the terminal device 2 so that the terminal device 2 in the content distribution system S is a content holding terminal device, as well as a plurality of content data distributed to the terminal device 2. (In other words, content data held by the content holding terminal device) has a function of generating an identification information list that is an identification information list in which the name of the content and the content ID are associated with each other and providing the identification information list to the terminal device 2 ing.

  Further, in the second distribution form of the content distribution system S, the contact destination introduction device 5 is arranged. The contact introduction device 5 is configured so that when a terminal device 2 that has not participated in the second distribution form of the content distribution system S has requested to participate in the second distribution form, the terminal apparatus 2 that has not participated participated in the message. Has the function of notifying the location information of the terminal device 2 that has already participated (hereinafter referred to as “contact destination terminal device”).

[1.2.2 Creating a routing table]
Here, an example of a method for creating a routing table used in DHT will be described with reference to FIG. FIG. 8 is a diagram illustrating an example of how a routing table is created by DHT.

  First, as shown in FIG. 8A, the ID space is divided into several areas. Actually, about 16 divisions are often used, but in order to simplify the explanation, four divisions are used here, and the ID is represented by a quaternary number having a bit length of 8 bits. An example in which the terminal ID of the terminal device 2N is “1133” and the routing table of the terminal device 2N is created will be described.

(Level 1 routing)
First, if the ID space is divided into four areas, each area is represented by four areas “0XXX”, “1XXX”, “2XXX”, “3XXX” (X is a natural number from 0 to 3, The same shall apply hereinafter.) Since the terminal ID of the terminal device 2N itself is “1133”, the terminal device 2N exists in the lower left “1XXX” area in FIG. The terminal device 2N is a terminal device existing in an area (that is, an area of “0XXX”, an area of “2XXX”, an area of “3XXX”) other than the area where the terminal device exists (that is, the area of “1XXX”). 2 is appropriately selected, and the location information of the terminal ID, that is, the IP address of the terminal ID is stored in the level 1 table. FIG. 9 is an example of a level 1 table. In this table, “0100” is selected as the terminal ID of the “0XXX” area, “2133” is selected as the terminal ID of the “2XXX” area, and “3213” is selected as the terminal ID of the “3XXX” area. Show. Since the second column of level 1 indicates the terminal device 2N itself, it is not necessary to store the IP address.

(Level 2 routing)
Next, as shown in FIG. 8B, among the areas divided into four by the above routing, the area “1XXX” where the user exists is further divided into four, and further four areas “10XX” “11XX”, “12XX” , “13XX”. Then, similarly to the above, the terminal device 2 existing in an area other than the area “11xx” in which it is present is appropriately selected, and the IP address that is the location information of the terminal ID is stored in the level 2 table. FIG. 9 is an example of a level 2 table. In this table, “1003” is selected as the terminal ID of the “10XX” area, “1221” is selected as the terminal ID of the “12XX” area, and “1313” is selected as the terminal ID of the “13XX” area. Is shown. The second column of level 2 is an area “11XX” in which the terminal device 2N exists, and since it is tabulated at level 3 to be described later, no IP address is stored. When the terminal device 2 does not exist in the area, the terminal ID and IP address fields are blank.

(Level 3 routing)
Further, of the areas divided into four by the above routing, the area “11XX” where the user exists is further divided into four, and further divided into four areas “110X”, “111X”, “112X”, and “113X”. Then, similarly to the above, the terminal device 2 existing in an area other than the area “113X” in which it exists is appropriately selected, and the IP address that is the location information of the terminal ID is stored in the level 3 table. FIG. 9 is an example of a level 3 table. The fourth column of level 3 is an area where the terminal device 2N exists, and since it is tabulated at level 4 described later, no IP address is stored. If there is no terminal device in the area, the terminal ID and IP address fields are blank.

  In this way, all the 8-bit IDs can be covered by creating a routing table in the same way up to level 4 as shown in FIG. As the level goes up, white space becomes more noticeable in the table.

  All the terminal devices 2 create and own the routing table created according to the method described above. Thus, each terminal device 2 has a routing table that associates terminal IDs (identification information) and IP addresses (location information) of some terminal devices 2 among the plurality of terminal devices 2 in the content distribution system S. This routing table is stored in the routing table storage means described later.

  By the way, when the terminal device 2 has not participated in the second distribution form, the terminal device 2 does not know the location information of the terminal device 2 participating in the second distribution form. Therefore, when participating in the second distribution form, the terminal device 2 generates a routing table as described in the next section.

[1.2.3. Participation in the second distribution form]
Next, an example of a method in which the terminal device 2 that has not participated in the second distribution form in the content distribution system S participates in the second distribution form will be described with reference to FIG. FIG. 10 is a diagram illustrating an example of a state in which a terminal device 2M that has not participated in the second distribution form (hereinafter referred to as “new participation terminal apparatus 2M”) participates in the second distribution form.

  First, a new participation terminal apparatus 2M that has not participated in the second distribution form should transmit a participation message to the contact introduction apparatus 5 in order to participate in the second distribution form of the content distribution system S. 2 (hereinafter referred to as “contact destination terminal device”) is requested.

  The new participation terminal device 2M transmits a participation message to the contact destination terminal device when the location information of the contact destination terminal device to which the participation message is to be transmitted is sent from the contact destination introduction device 5. Here, the destination identification information of the participation message is the terminal ID of the new participation terminal device 2M. That is, the new participation terminal apparatus 2M generates a participation message using the hash value “2133” of the IP address of the own apparatus 2 as the destination identification information when participating in the second distribution form.

  When the contact destination terminal device receives the participation message transmitted from the new participation terminal device 2M, the contact destination terminal device determines whether or not the participation message is a message addressed to the contact destination terminal device. Whether the message is addressed to the contact destination terminal device is determined based on the destination identification information and the routing table. Specifically, it is determined whether the destination identification information is close to the identification information addressed to the contact destination terminal device. That is, with respect to the destination identification information, the terminal device identification information stored in the routing table held by the contact destination terminal device itself is the closest terminal device identification information itself or another terminal. Determine if it is a device. When the identification information of the other terminal device is closer to the destination identification information than the identification information of the contact destination terminal device, the contact destination terminal device that has received the participation message is the routing held by the contact destination terminal device itself. Referring to the level 2 of the table, among the terminal devices 2 belonging to the area “2XXX”, the participation message is transferred to the terminal device 2B that knows the IP address, and is stored in the routing table storage means of the own terminal device. The information of the level 1 table of the stored routing table is transmitted to the newly participating terminal apparatus 2M.

  In this way, the participation message is transferred in such a manner that the digits of the content ID are adapted in order from the top, and information on each level of the routing table is sequentially transmitted. When the terminal device 2 that finally comes closest to the destination identification information is reached, the transfer of the participation message ends. A mechanism for transferring a message such as a participation message to the target terminal device as described above is called DHT routing.

  In this way, the new participation terminal device 2M obtains the information of each level of the routing table from the higher level information in order from the terminal device 2 that has received the participation message. In this way, the new participation terminal 2 generates a routing table necessary for participating in the second distribution form.

[1.2.4. Content data search method]
Next, an example of a search method for the terminal device 2 that holds content data will be described with reference to FIG. FIG. 11 is a diagram illustrating an example of a state in which the terminal device 2 holding content data is searched by DHT routing.

  Here, a procedure when the terminal device 2N having the terminal ID “1133” searches for content data having the content ID “3020” will be described. Hereinafter, a terminal device that searches for content data and requests reception of content data in this way is referred to as a “request terminal device”.

  The requesting terminal device 2N refers to the level 1 table of the routing table held by itself, and uses the terminal ID of the terminal device having the terminal ID in the same area as the content ID “3020” as the destination identification information. A transmission request (hereinafter referred to as “content search message”) of device information (information including location information of the content holding terminal device) is transmitted. That is, since the content ID “3020” is an area of “3XXX”, the terminal device 2 belonging to the area of “3XXX” knows the IP address (that is, the IP address is stored in the routing table held by itself). A content search message is transmitted to the terminal device 2A (terminal ID “3213”) in which the address is stored. Thus, the content search message includes a content ID that is unique identification information corresponding to the content, and this content ID is used as destination identification information in the content search message.

  According to the example shown in FIG. 11, since the IP address of the terminal device 2A whose terminal ID is “3213” is stored in the routing table (see FIG. 9) of the request terminal device 2N, the request terminal device 2N A content search message is transmitted to the terminal device 2A whose terminal ID is “3213”.

  Next, the terminal device 2A that has received the content search message determines whether or not the content search message is a message addressed to the terminal device 2A. Whether the message is addressed to the terminal device 2A is determined based on the destination identification information and the routing table. Specifically, it is determined whether the destination identification information is close to the identification information of the terminal device 2A. That is, with respect to the destination identification information, the identification information of the terminal device closest to the terminal device identification information stored in the routing table held by the terminal device 2A itself is itself or another terminal device. It is determined whether it is. Here, since the identification information of the other terminal device is closer to the destination identification information than the identification information of the terminal device 2A, the terminal device 2A is level 2 of the routing table held by the terminal device 2A itself. The content search message is transferred to the terminal device 2B (terminal ID “3031”) that knows the IP address among the terminal devices 2 belonging to the area “30XX”.

  In this way, the transfer of the content search message proceeds in the manner of adapting the digits of the content ID in order from the top, and finally the terminal device 2C (terminal ID “3011”) that manages the content data, that is, the root terminal device When the route terminal device arrives, the root terminal device searches the content ID “3020” included in the content search message from index information (described later) managed by itself, and retains the content data that owns the content data. The IP address of the terminal device is returned to the request terminal device 2N.

  In this way, the request terminal device 2N receives the location information of the content data with the content ID “3020” from the root terminal device 2C, that is, the IP address of the content holding terminal device that holds the content data with the content ID “3020”. The content data is downloaded and acquired from the content holding terminal device.

[1.2.5. How to register in the index table]
In the second distribution form in the content distribution system S, a method for publishing new content data so as to be visible to other terminal devices 2 on the content distribution system S will be described.

  As shown in FIG. 12, the second distribution form of the content distribution system S in this embodiment is a management target for each content holding terminal device with respect to the terminal device 2 in which the content input device 4 is each content holding terminal device. Send content data as content. The content holding terminal device that has received the content data to be managed from the content input device 4 stores the received content data in the hard disk device 203 described later.

  As shown in FIGS. 12 and 13, the content holding terminal device to which the content data has been distributed is a content holding terminal device information registration request message (hereinafter referred to as “contents” including location information and identification information of the content holding terminal device). "Registered message") is transmitted to the terminal device having the same terminal ID as the content ID obtained from the content name or the like (whether or not this terminal device actually exists is not known at this time). Then, the content registration messages are also sequentially transferred according to the routing table in the same manner as the content search message, and are transferred to the terminal device 2 having the terminal ID closest to the content ID included in the content registration message. When the terminal device 2 determines that there is no other destination terminal device, the terminal device 2 determines that the terminal device 2 itself should be the root terminal device of the content, and the content registration as shown in FIG. The content ID which is the content holding terminal device information included in the message, the IP address of the content holding terminal device, and auxiliary information (attribute information such as title, genre, extended information, copyright information such as director name, streaming time, etc. ) As index information described later And stores it in the Buru 222.

  Thus, when the IP address, which is the location information of the content holding terminal device, is registered in the index table 222 of the root terminal device, the content holding terminal device registered in the index table in response to the content search message from the requesting terminal device thereafter. The location information is returned to the requesting terminal device. In this way, in the present embodiment, the content distributed from the content input device 4 is registered in the content holding terminal device, and can be searched via the root terminal device, so that the content is disclosed to other terminal devices. .

  As shown in FIG. 14, the index table 222 is a table for storing content holding terminal device information including an IP address that is location information (location information) of the content holding terminal device. In the index table 222, the IP address of the content holding terminal device, the time when the content holding terminal device was introduced, and the like are stored for each row (predetermined storage area) as content holding terminal device information.

[2. Description of Content Distribution Device 1 Configuration]
Next, the configuration and operation of the content distribution apparatus 1 will be described in more detail with reference to FIG.

  FIG. 17 is a diagram illustrating a schematic configuration example of the content distribution apparatus 1 in the present embodiment. The content distribution apparatus 1 can be applied to a general server computer. As shown in FIG. 17, a CPU (Central Processing Unit) 102 and a main rewritable main storage device that stores (stores) various programs and the like. A storage device 105, a hard disk device 103 that stores various data, a network interface 104 that communicates with the terminal device 2, the connection management device 3, and the content input device 4 via the network 6, and predetermined information The peripheral device control chip 106 that controls input means such as the keyboard 107 and the mouse 108 that can be input and the image data from the CPU 102 are received and written to an internal video memory (not shown), and the data written to this video memory is described later. Built-in display 110 From the video chip 109 to be displayed, the built-in display 110 that performs display in accordance with the signal transmitted from the video chip 109, the sound source chip 111 having a sound source such as an FM sound source (Frequency Modulation) or Wave Table sound source, and the sound source chip 111 And a built-in speaker 112 that converts an audio signal to be output into sound waves, and these various components are connected to each other via a system bus 101.

  The network interface 104 is connected to the network 6 via the router 10a. This router 10a corresponds to the router 10 shown in FIG.

  In the present embodiment, the CPU 102 and the main storage device 105 constitute a control unit 130. In addition, the content distribution apparatus 1 includes the built-in display (liquid crystal display or the like) 110 as described above. For example, a broadcast operator who operates the content distribution system S inputs while viewing the built-in display 110. Predetermined information can be input from the means. In the present embodiment, the built-in display 110, the built-in speaker 112, and the like are built in the content distribution apparatus 1. However, the present invention is not limited to this, and may be connected separately, for example.

(Main memory 105)
The main storage device 105 also stores an OS (operating system) program 117 for providing basic functions as a computer of the content distribution device 1 and content data stored in the broadcast content storage area of the hard disk device 103. A stream control program 115 for taking out and streaming to the terminal device 2, and a topology management program 116 for managing location information (IP address, port number, etc.) of each terminal device 2 connected to each channel A screen control program 118 for controlling the built-in display 110, a music decoder program 119 for decoding the encoded music content data, and broadcast content data 113 stored in the hard disk device 103. The ring buffer area 120 that temporarily stores the read content data before being transmitted to the terminal device 2 and the content data distributed to the downstream terminal device 2 are received from the content input device 4 for each channel and stored in the hard disk device 103. The stored content management program 121 and the like are stored, and these are read by the CPU 102, and the function according to these programs is executed by the CPU 102.

  Here, the OS program 117 is read and executed by the CPU 102, whereby the contents distribution device 1 such as a function related to input / output of the keyboard 107 and the mouse 108 and memory management such as the main storage device 105 and the hard disk device 103. It is possible to execute the basic functions of a computer.

  Then, with the OS program 117 being executed by the CPU 102, the above-described stream control program 115, topology management program 116, screen control program 118, music decoder program 119, and content management program 121 are read from the main storage device 105. Executed.

  The OS program 117, the stream control program 115, the topology management program 116, the screen control program 118, the music decoder program 119, the content management program 121, and the like are downloaded to the main storage device 105 from a server connected to the network 6, for example. Alternatively, after being recorded on a recording medium such as a CD-ROM, it may be read into the main storage device 105 via a drive of the recording medium.

(About the control unit 130)
The control unit 130 includes the CPU 102 and the main storage device 105 as described above, and the CPU 102 reads out and executes the various programs 115 to 119 and 121 stored in the main storage device 105, whereby the entire content distribution device 1. And functions as a content data distribution means, which will be described later. When the CPU 102 executes the stream control program 115, the CPU 102 executes the screen control program 118 as a content data distribution unit or the like, and when the CPU 102 executes the topology management program 116, as the topology management unit. As a display control unit, the CPU 102 executes the music decoder program 119, and as a playback unit, the CPU 102 executes the content management program 121, thereby functioning as a distribution content reception unit and a distribution content storage unit. It is supposed to be. Further, the hard disk device 103 is used as content data storage means for storing content data.

(About distribution content receiving means and distribution content storage means)
The distribution content receiving means requests the content input device 4 to transmit content data, and receives the content data transmitted from the content input device 4 and the name of the content. In addition, the distribution content storage unit stores the received content data as the broadcast content data 113 in the hard disk device 103 when the content data is received from the content input device 4 by the distribution content reception unit.

  The hard disk device 103 stores in advance broadcast program information for storing the order of content data to be broadcast on each channel, and the distribution content receiving means sends the content input device 4 to the content input device 4 based on the program information. The content data to be transmitted is determined and a transmission request to the content input device 4 is made.

  The distribution content receiving means does not make a content data transmission request to the content input device 4 based on the broadcast program information, but stores the broadcast program information in the hard disk device 403 of the content input device 4 to The input device 4 may sequentially transmit the content data based on the broadcast program information. In this case, the content distribution device 1 sequentially distributes the content data input by the content input device 4 to the downstream device for each channel.

(About content data distribution means)
The content data distribution unit distributes the content data through the network 6 in a streaming manner. That is, the broadcast content data stored in the hard disk device 103 is taken out and streamed to the terminal device 2 logically connected via the network 6 (for example, the top-level terminal device when connected in a tree shape). To do. The content data also includes information such as the name of the content.

  The streaming distribution to the terminal device 2 or the like by the content data distribution unit is executed according to the following procedure.

  The content data distribution means sequentially extracts the content data based on the broadcast program information from the broadcast content data 113 stored in advance in the hard disk device 103 and stores it in the ring buffer area 120.

  Next, the content data distribution unit encodes the content data extracted from the ring buffer area 120 into a data format for streaming distribution, for example, a data format such as ASF, WMA, and WMV.

  Thereafter, the content data distribution means stores the corresponding content data in the content packet for each of the terminal devices 2 and the like connected to the terminal device 2 and the like, and transmits the content data to the content packet via the network 6. .

  Note that the content data distribution unit may flow the content selected by the input unit such as the keyboard 107 using a DJ or the like.

(About topology management means)
The content distribution apparatus 1 is allocated with a plurality of channels, and the topology management means is the location information (IP address) of the terminal apparatus 2 participating in the first hierarchy of the tree-like hierarchical structure constituted by the allocated channels. And port numbers) are managed for each channel. The distribution means distributes content data to the terminal apparatus 2 using the IP address of the terminal device 2 managed by the topology management means as the destination address and the distribution IP address as the transmission source.

(Display control means)
The display control means has a function of controlling the video chip 109 and the built-in display 110 to display content data and various types of information. That is, the display control means can control how the content video and various types of information are displayed on the built-in display 110.

(About playback means)
The reproduction means has a function of displaying the broadcast content data 113 on the built-in display 110 and outputting it from the built-in speaker 112.

[3. Description of Configuration of Terminal Device 2]
Next, the configuration and operation of the terminal device 2 will be described in more detail with reference to FIG. FIG. 18 is a diagram illustrating a schematic configuration example of the terminal device 2 in the present embodiment.

  The terminal device 2 can be a general personal computer or a dedicated terminal. As shown in FIG. 18, a CPU (Central Processing Unit) 202 and a rewritable main storage device 205 that stores (stores) various programs and the like. Between the hard disk device 203 for storing various data and the like, and the content distribution device 1, the connection management device 3, the content input device 4, the contact introduction device 5 and other terminal devices 2 on the network via the network 6. A network interface 204 for performing communication by wired communication, a user input remote control 208 that transmits and receives a predetermined infrared signal that allows the user to remotely operate the terminal device 2, and the user input remote control 208 and infrared rays. Infrared port 2 for communication 07, a peripheral device control chip 206 for controlling the infrared port 207, and image data from the CPU 202, written to an internal video memory (not shown), and displayed on the internal display 210 to be described later. Video chip 209, built-in display 210 that performs display in accordance with the signal transmitted from video chip 209, sound source chip 211 having a sound source such as FM sound source (Frequency Modulation) or Wave Table sound source, and output from sound source chip 211 And a built-in speaker 212 for converting the audio signal to sound waves, and these various components are connected to each other via a system bus 201.

  In the present embodiment, the CPU 202 and the main storage device 205 constitute a control unit 230. The network interface 204 is connected to the network 6 via the router 10b. This router 10b corresponds to the router 10 shown in FIG.

  With the user input remote control 208 as described above, operations such as purchase of content in the content distribution system S are possible. The remote controller 208 for user input in the present embodiment has a channel selection button as a selection means for selecting a channel of the content distribution system S, and the user of the terminal device 2 connects to a desired channel using this channel selection button. can do. As shown in FIG. 15, channel selection buttons 22 and 23 may be displayed on the screen of the built-in display 210 and a channel may be selected by operating the remote control 208.

(About the main storage device 205)
Further, the main storage device 205 includes an OS program 217 for providing basic functions of the terminal device 2 as a computer, and relays directly from the content distribution device 1 to another terminal device 2 in the first distribution mode. Stream control program 215 for receiving streamed and streamed content data to stream terminal device 2 and downstream terminal device 2 and terminal device 2 (or content distribution device) connected in a tree connection in the first distribution mode 1) topology management program 216 for managing location information (IP address and port number) of location information of terminal device 2 further downstream in a tree connection, and screen control program for controlling built-in display 210 218 and in the first distribution mode, the upstream device A music decoder program 219 for decoding the content data received for streaming and playing it back, or playing back the content data downloaded in the second distribution form and stored in the hard disk device 203; and a predetermined storage capacity The ring buffer area 220 for temporarily storing the received content data in a stream and the content data are streamed and played back in the first distribution form, and the content data is requested to be downloaded by the operation of the remote control 208 or the like. 2 A content purchase program 221 for downloading content data in the form of distribution is stored, which is read out by the CPU 202, and functions according to these programs are executed by the CPU 202.

  The main storage device 205 is further provided with an index table storage area for storing the index table 222 (see FIG. 14) and a routing table storage area for storing the routing table 223 (see FIG. 9). .

  The ring buffer area 220 is an area for temporarily storing content data distributed in participating channels (viewing channel and zapping countermeasure channel) for each channel, and is accumulated in the ring buffer area of the zapping countermeasure channel. Since the content data is used only for relaying without being reproduced, the ring buffer area has a smaller capacity than the ring buffer area of the reproduction channel. Since the ring buffer area of the zapping countermeasure channel is thus reduced, the main storage device 205 can be used efficiently. Of course, it is also possible to make the capacities of all the ring buffer areas the same by setting or the like.

  Here, the OS program 217 is read out and executed by the CPU 202, thereby causing the terminal device 2 such as a function related to input / output of the user-input remote control 208 or memory management such as the main storage device 205 and the hard disk device 203. It enables the basic functions of a computer to be executed. Then, with the OS program 217 being executed by the CPU 202, the above-described stream control program 215, topology management program 216, screen control program 218, music decoder program 219, content purchase program 221 and the like are read from the main storage device 205. To be executed.

  The OS program 217, the stream control program 215, the topology management program 216, the screen control program 218, the music decoder program 219, the content purchase program 221 and the like are downloaded to the main storage device 205 from, for example, a server connected to the network 6. Alternatively, the data may be recorded on a recording medium such as a CD-ROM and then read into the main storage device 205 via a drive of the recording medium.

(About the control unit 230)
The control unit 230 is configured by the CPU 202 and the main storage device 205 as described above, and the CPU 202 reads and executes the various programs 215 to 219 and 221 stored in the main storage device 205, thereby executing the entire terminal device 2. Centralized control and connection means, streaming reception means, display control means, streaming playback means, streaming relay means, decoding means, identification information acquisition means, identification information list reception means, download operation detection means, disconnection means, replay, Connection means, determination means, download processing means, message destination determination means, content data storage control means, content holding terminal device information selection means, content holding terminal device information return means, content identification information calculation means, content registration message generation means, content Registration Messe Di transmission means, the message transferring means, and functions as a content playback device or the like.

  It should be noted that the CPU 202 executes the stream control program 215 as streaming receiving means, streaming relay means, etc., and the CPU 202 executes the topology management program 216 as connection means, etc., and the CPU 202 executes the screen control program 218. As a display control unit, the CPU 202 executes the music decoder program 219, and as a decoding unit, a streaming playback unit, a content playback unit, etc., and the CPU 202 executes the content purchase program 221, thereby identifying the identification information list. Reception means, identification information acquisition means, determination means, download operation detection means, disconnection means, reconnection means, download processing means, content data storage control means, message Function as a message destination determination unit, a content holding terminal device information selection unit, a content holding terminal device information return unit, a content identification information calculation unit, a content registration message generation unit, a content registration message transmission unit, a message transfer unit, etc. It has become.

(About connection means)
The connection means connects the connection destination introduction request regarding the channel selected by the user's operation of the channel selection button of the remote control 208 as the channel selection means in order to cause the terminal device 2 to participate in the first distribution form of the content distribution system S. It transmits to the management apparatus 3 and then connects to the connection destination candidate notified from the connection management apparatus 3. Further, the connection means transmits a connection destination introduction request regarding a channel (zapping countermeasure channel) having a predetermined relationship with the channel selected by the channel selection means to the connection management apparatus 3, and then notified from the connection management apparatus 3. Connect to connection destination candidates.

  More specifically, the connection means transmits a registration request to the connection management device 3 to register it in the connection management device 3 and transmits a connection destination introduction request in order to cause the terminal device 2 to participate in the content distribution system S. Thus, the connection management apparatus 3 has a function of requesting the connection destination candidate of the channel selected by the channel selection means and the connection destination candidate of the channel having a predetermined relationship with the channel. In this registration request or connection destination introduction request, information specifying the channel selected by the user of the terminal device 2 operating the channel selection button or the like of the remote control 208, or the channel having a predetermined relationship with the selected channel. Information, location information of the terminal device 2 and the like.

  In addition, the connection means responds to the connection destination introduction request transmitted to the connection management device 3, and information on the connection destination candidates of the viewing channel and the zapping countermeasure channel notified from the connection management device 3 via the network 6, that is, the connection It has a function of receiving information such as an IP address and a port number (hereinafter, abbreviated as “connection destination candidate” including information on connection destination candidates), which is the location information of the destination candidate terminal device.

  Further, the connection means has a function of performing logical connection to the connection destination candidate based on the received connection destination candidate information of each channel. In other words, the connection means makes a connection request with the destination IP address and port number as the destination based on the information about the destination candidate, and makes a logical connection with the destination candidate. By connecting with the connection destination candidates in this way, the channel is incorporated into the hierarchical structure of a plurality of channels (viewing channel and a plurality of zapping countermeasure channels) and participates in the first distribution form.

(About streaming receiving means)
The streaming receiving means transmits the content data transmitted as a content packet from the upstream device, that is, the content distribution device 1 logically connected upstream or the terminal device 2 connected upstream by the first distribution form via the network interface 204 in the channel ( Streaming reception is performed for each viewing channel and anti-zapping channel), and the content data thus streamed is sequentially stored in the ring buffer area 220 for each channel. It should be noted that the content data receiving means and the content data relay means described later can use a known streaming distribution protocol, or can use a unique dedicated protocol.

(About streaming playback means)
The streaming reproduction means has a function of sequentially reproducing the content data sequentially received from the upstream apparatus through the network interface 204 and stored in the ring buffer area 220 in the first distribution form.

  This streaming playback means operates the sound source chip 211 and the video chip 209 by taking out from the ring buffer area content data corresponding to the latest channel last selected by a channel selection button or the like among a plurality of participating channels. The content data stored in the ring buffer area 220 is sequentially extracted, converted into a predetermined content data format (for example, Wave format), and input to the sound source chip 211 and the video chip 209. , Play content.

  The content data converted into a predetermined content data format by the streaming reproduction means is output from the built-in speaker 212 after the audio information is converted into an audio signal by the sound source chip 211 when the content data includes audio information. Is done.

  In addition, when the content data converted into a predetermined content data format by the streaming playback means includes video information, the video information is displayed on the built-in display 210 under the control of the display control means described later.

  Also, the streaming playback means determines the timing for playing back the content data based on the playback start time information included in the content data stored in the ring buffer area 220. That is, the playback means is configured to output the content data stored in the ring buffer area 220 to the built-in speaker 212 and the built-in display 210 at the playback start time.

(Display control means)
The display control means has a function of controlling the video chip 209 and the built-in display 210 to display content data and various types of information. That is, the display control means can control how the content video and various types of information are displayed on the built-in display 210.

(About streaming relay means)
The streaming relay unit is configured to receive the content data stream-received via the network 6 from the upstream device in the first distribution form, that is, the content distribution device 1 or the terminal device 2 connected upstream, and the other terminal device connected downstream. 2 through the network 6.

(Identification information list receiving means)
The identification information list receiving unit has a function of receiving the identification information list transmitted from the content input device 4. The identification information list transmitted from the content input device 4 is information in which the name of the content data that can be downloaded and the content ID are associated with each other in the second distribution form, and the terminal device 2 sends the identification information list to the content input device 4. Is transmitted from the content input device 4.

(About download operation detection means)
The download operation detecting means has a function of detecting an operation of downloading content data according to the second distribution form. For example, as shown in FIG. 16, in a state where content data that can be downloaded in the second distribution form is listed in the predetermined area 24 of the built-in display 210, the user operates the remote control 208 to specify content data to be downloaded. By detecting that the download button 26 is selected by designating with the frame 25, an operation of a download request for content data in the second distribution form is detected.

(About cutting means)
The disconnecting means includes a connection destination candidate relating to a channel having a predetermined relationship with the channel selected by the channel selecting means among the channels connected by the connecting means when the download request detecting operation is detected by the download operation detecting means. Has a function of disconnecting the connection.

  Here, the disconnecting means is a case where there are a plurality of channels having a predetermined relationship with the channel selected by the channel selecting means, and when the download request detecting operation is detected by the download operation detecting means, the disconnecting means is connected by the connecting means. The connection with the connection destination candidates for all channels having a predetermined relationship with the channel selected by the channel selection means is disconnected. That is, the disconnecting means leaves the hierarchical structure of all the zapping countermeasure channels.

  When there are a plurality of zapping countermeasure channels in this way, all zapping countermeasure channels are withdrawn, so that a larger communication band can be secured and communication in the second distribution mode can be stabilized.

  The channels having a predetermined relationship are channels having channel numbers adjacent to the channel numbers selected by the channel selection unit as described above.

(About identification information acquisition means)
The identification information acquisition unit is content that is identification information of the content data requested to be downloaded in order to acquire the content data requested to be downloaded in the second distribution form when the download operation detection unit detects the download request operation. Get an ID.

  Acquisition of the content ID requested for download is performed as follows.

  When there is a download request operation regarding the content data reproduced by the streaming reproduction means in the first distribution form, the identification information acquisition means identifies the identification information of the content data requested for download from the identification information list received by the identification information list reception means. Is obtained.

  Here, the identification information acquisition means may obtain the content ID of the content data requested to be downloaded by the content identification information calculation means described later. That is, the content ID is obtained by hashing with the hash function using the name of the content data requested for download as a keyword. Thus, by obtaining the content ID using the name of the content data requested for download as a keyword, the download processing in the second distribution form in the terminal device 2 is facilitated. The name of the content that can be downloaded in the second distribution form is acquired from the content input device 4 in the form of a list, etc., and the content identification information calculation means acquires the name of the content from the list, etc. The content ID can be calculated.

(Judgment means)
The determination unit determines whether or not the entire content data requested to be downloaded is stored in the ring buffer area 220.

  Here, when the own terminal device functions as a content holding terminal device, the content data to be held as the content holding terminal device is stored in a content data storage area (corresponding to an example of content data storage means) of the hard disk device 203. Is done. Similarly, content data downloaded in the past is also stored in the content data storage area of the hard disk device 203. The determination unit determines whether or not the content data requested to be downloaded is stored in the content data storage area of the hard disk device 203.

(Content data storage control means)
When the content data storage control means determines that the entire content data requested to be downloaded is stored in the ring buffer area 220 by the determination means, the content data storage control means does not download the content data in the second distribution form, and the ring buffer area The content data stored in 220 is stored in the content data storage area of the hard disk device 203. If the determination unit determines that the entire content data requested to be downloaded is stored in the ring buffer area 220, the disconnection unit does not disconnect the connection destination candidate of the channel in the connected state.

  If the determination unit determines that the content data requested for download is stored in the content data storage area of the hard disk device 203, the disconnection unit does not disconnect the connection destination candidate of the connected channel. The download processing means described later does not download the content data in the second distribution form.

(About download processing means)
The download processing means has a function of downloading the content data requested to be downloaded from the terminal device in the second distribution form based on the identification information of the content data acquired by the identification information acquisition means. , Download transmission request means, download data reception means, and the like.

  The download destination search unit searches for a content holding terminal device that holds the content data requested for download based on the content ID of the content data acquired by the identification information acquisition unit.

  The search for the content holding terminal device generates a content search message with the content ID acquired by the identification information acquisition means as the destination identification information, and stores the location information of the terminal device having the terminal ID in the same area as the content ID in the routing table The content search message is taken out from H.223 and transmitted to the terminal device.

  In response to the content search message, location information of the content holding terminal device that holds the content data of the content ID acquired by the identification information acquisition unit is transmitted from the root terminal device.

  In this way, the download destination search means searches for a content holding terminal device that holds the content data requested to be downloaded.

  The download transmission request means requests the content holding terminal device searched by the download destination search means to transmit the content data requested for download via the network 6 (hereinafter referred to as “download transmission request”). . This download transmission request sets the content ID of the content data corresponding to the download request with the location information of the content holding terminal device as the destination. If there are a plurality of content holding terminal devices searched by the download destination searching means, a download transmission request is made to one of the nearby content holding terminal devices.

  Here, the “neighboring content holding terminal device” means a terminal device that makes a download transmission request, a terminal device having a terminal ID close to the content holding terminal device in DHT routing, or a content holding terminal device close to the physical network. To do. In particular, when the content holding terminal device that makes a download transmission request is a content holding terminal device that is close to the physical network, the content data can be downloaded from the content holding terminal device in a short time. Note that “close to the physical network” means that the message arrival time from the terminal device that issues the download transmission request is short, or that the number of pops (number via the router) from the terminal device that issues the download transmission request is small. To do.

  The download data receiving unit receives the content data requested to be downloaded from the content holding terminal device that holds the content data requested to be downloaded via the network 6. The content data transmitted from the content holding terminal device is not in the streaming format as in the first distribution form but in the download format, but can also be in the streaming format.

  The content data received by the download receiving means is stored in the content data storage area of the hard disk device 203 by the control unit 230.

(Reconnection method)
When the download data receiving unit completes the content data requested to be downloaded, the reconnection unit transmits a connection destination introduction request regarding the zapping countermeasure channel disconnected by the disconnection unit to the connection management device 3, and then the connection management device. 3 has a function of reconnecting to the connection destination candidate notified from 3.

  Note that this reconnection means may be reconnected to the zapping countermeasure channel disconnected by the disconnection means after the reception by the download data reception means is completed and a predetermined period has elapsed. The predetermined period may be changed according to the usage status of the second distribution form in the terminal device 2. For example, the history of continuous usage time in the second distribution form can be stored in the hard disk device 203, and the predetermined period can be determined according to the average time of continuous usage time. In this way, it is possible to reduce the state in which the channel is frequently disconnected by the disconnecting means and the channel is reconnected by the reconnecting means. As a result, the load on each hierarchical structure in the first distribution form is reduced. It becomes possible to do.

(About message destination determination means)
The message destination determination means determines whether or not the received message is addressed to the own terminal device 2 based on the destination identification information of the message received via the network 6 and the routing table. The message determined by the message destination determination means is the above-described content search message, content registration message, or the like.

  Whether or not the received message is addressed to the own terminal device 2 is determined based on the routing table stored in the main storage device 205 by extracting the destination terminal ID (destination identification information) included in the message. That is, when various messages are received via the network interface 204, the message destination determination unit compares the destination identification information included in the received message with the terminal ID stored in the routing table 223, and the destination included in the message. If it is determined that the terminal ID on the routing table 223 closest to the identification information is the terminal ID of the own terminal device 2, it is determined that the message is addressed to the own terminal device 2.

(About content holding terminal device information selection means)
When the content holding terminal device information selection unit determines that the message received via the network 6 by the message destination determination unit is addressed to the terminal device 2 and is a content search message, the content search message is selected from the index table 222. The location information of the content holding terminal device that holds the content data of the content ID is selected. When there are a plurality of pieces of location information of content holding terminal devices in the index table 222, all or some of them are selected.

(About content holding terminal device information return means)
The content holding terminal device information return means returns the location information of the content holding terminal device selected by the content holding terminal device information selection means to the request terminal device via the network 6.

(About content identification information calculation means)
The content identification information calculation means calculates the content ID that is the identification information of the content data by calculating the specific information of the content data by a predetermined hash function as described above.

(About content registration message generation means)
When content data is received from the content input device 4, the received content data is stored in a content data storage area (corresponding to an example of content data storage means) of the hard disk device 203. Further, a content registration message including the terminal ID and the IP address of the terminal device is generated using the content ID calculated by the content identification information calculating means as the destination ID information.

(About content registration message transmission means)
The content registration message transmission means transmits the content registration message generated by the content registration message generation means from the identification information of the terminal device stored in the routing table 223 based on the content ID of the content data stored in the hard disk device 203. Select a terminal device and send it. For example, if the content ID of the content data stored in the hard disk device 203 is “1231” having the routing table as shown in FIG. "Is selected as the destination terminal device, and the IP address" 21.13.21.13 "of the terminal device with the terminal ID" 1221 "is extracted. Then, the content registration message is transmitted using the IP address “21.13.21.13” as the transmission destination terminal device. The destination identification information of this content registration message is “1231”.

(About message transfer means)
When the message transfer means determines that the message received via the network 6 is not addressed to its own terminal device, the message transfer means determines the location information of the transfer destination terminal device based on the destination identification information of the received message. Is transferred from the routing table 223 and the received message is transferred to the transfer destination terminal device.

(Decoding means)
The decoding means displays the content data transmitted from the other terminal device 2 on the display 210 and decodes it for output from the speaker 212. That is, the content data transmitted from the other terminal device 2 is encoded in a data format for streaming delivery, for example, a data format such as ASF, WMA, WMV, and the encoded content data is displayed on the display 210. And decoding so that it can be output from the speaker 212.

(About content playback means)
The content reproduction means retrieves and reproduces the content data stored in the hard disk device 203. At this time, the control unit 230 operates the video chip 209 and the sound source chip 211 on the basis of the stream control program 215, thereby generating the content data. Is played.

[4. Description of Configuration of Connection Management Device 3]
Next, the configuration and operation of the connection management device 3 will be described with reference to FIG.

  FIG. 19 is a diagram illustrating a schematic configuration example of the connection management device 3 in the present embodiment. The connection management device 3 is applicable to a general server computer. As shown in FIG. 19, a CPU (Central Processing Unit) 302, a rewritable main storage device 305 that stores (stores) various programs, and the like, A hard disk device 303 that stores various data, a network interface 304 that communicates with the content distribution device 1, the content input device 4, and the terminal device 2 via the network 6, and a keyboard 307 that can input predetermined information. The peripheral device control chip 306 for controlling the input means such as the mouse 308 and the video receiving the image data from the CPU 302 and writing it to the internal video memory (not shown) and displaying the data written to the video memory on the display 310 Chip 309 and These various components are connected to each other via a system bus 301.

  In the present embodiment, the CPU 302 and the main storage device 305 constitute a control unit 330. The network interface 304 is connected to the network 6 via the router 10c. This router 10c corresponds to the router 10 shown in FIG.

(About the main storage device 305)
The main storage device 305 manages an OS program 317 for providing basic functions of the connection management device 3 as a computer, and location information (such as IP addresses and port numbers) of a plurality of terminal devices 2. Terminal management program 318, a topology management program 319 for constructing and managing such that a plurality of terminal devices are logically connected in multiple layers in a tree-like hierarchical structure on the network with the content distribution device at the top, and a terminal A connection destination introduction program 320 for selecting a connection destination candidate in response to a connection destination introduction request transmitted from the device 2 and transmitting connection destination candidate information to the terminal device 2 is stored. And the function according to these programs is executed by the CPU 302.

  Here, the OS program 317 is read and executed by the CPU 302, whereby functions related to input / output of the keyboard 307 and mouse 308, and connection management device 3 such as memory management of the main storage device 305 and hard disk device 303. It is possible to execute the basic functions of a computer. Then, with the OS program 317 being executed by the CPU 302, the terminal management program 318, topology management program 319, connection destination introduction program 320, and the like are executed.

  Note that the OS program 317, the terminal management program 318, the topology management program 319, the connection destination introduction program 320, and the like may be downloaded to the main storage device 305 from, for example, a server connected to the network 6. Alternatively, after being recorded on a recording medium such as a CD-ROM, it may be read into the main storage device 305 via a drive of the recording medium.

(Regarding the controller 330)
The control unit 330 is configured by the CPU 302 and the main storage device 305 as described above, and the CPU 302 reads out and executes various programs 317 to 320 stored in the main storage device 305 to control the entire connection management device 3. It controls and functions as connection destination introduction request receiving means, connection destination candidate selection means, connection destination candidate notification means, topology management means, terminal management means, etc., which will be described later. Further, the hard disk device 303 is used as connection state information storage means for storing connection state information of a plurality of terminal devices logically connected in multiple layers in a hierarchical structure on the network 6 with the content distribution device 1 as a vertex. The

  The CPU 302 executes the terminal management program 318 as a terminal management unit or the like, and the CPU 302 executes the topology management program 319 as a topology management unit or the like, and the CPU 302 further executes the connection destination introduction program 320. Function as connection destination introduction request receiving means, connection destination candidate selecting means, connection destination candidate notifying means, and the like.

(About terminal management means)
When receiving the registration request from the terminal device 2, the terminal management means registers the IP address, which is the location information of the terminal device 2, in the terminal management database 314 for each channel. In addition, when a registration request is received from the content distribution apparatus 1, the location information of the content distribution apparatus 1 is registered in the terminal management database 314 for each channel. The location information of the terminal device 2 is included in the registration request from the terminal device 2, and the location information is acquired from the registration request.

(About topology management means)
The topology management means includes a new topology generation means for generating a tree-like hierarchical structure based on a channel generation request transmitted from the content distribution apparatus 1, and a connection destination introduction request or a connection disconnection notification of the terminal device 2. It has a function as topology changing means for changing connection information of the terminal device 2 in the tree-like hierarchical structure by topology change notification. Further, the topology management unit stores the connection state information of the terminal devices 2 constituting the hierarchical structure in the topology database 315 as the connection state information storage unit.

  When receiving a channel generation request from the content input device 4, the new topology generation unit generates a topology table and registers it in the topology database 315. Here, the topology table is a table for storing connection state information and the like of the terminal devices 2 constituting the tree-like hierarchical structure, and is registered in the topology database 315.

  The topology change means executes a function of adding or deleting information of the terminal device 2 to / from the topology table stored in the topology database 315. Based on the connection destination introduction request topology participation report from the terminal device 2, the topology change means Add or change to the table.

(About connection destination introduction request receiving means)
The connection destination introduction request receiving unit receives a connection destination introduction request via the network 6 from the terminal device 2 that is newly participating in the first distribution form or trying to use a new channel.

(About connection destination candidate selection means)
When the connection destination candidate selection means receives a connection destination introduction request via the network 6 from the terminal device 2 that newly intends to participate in the first distribution form or to join the new channel, the connection destination introduction request of the terminal device 2 Is selected from connection state information stored in the topology database 315.

(About connection destination candidate notification means)
The connection destination candidate notification unit has a function of notifying the terminal device 2 that has transmitted the connection destination introduction request via the network 6 of the connection destination candidate selected by the connection destination candidate selection unit. The notification of the connection destination candidate includes information on the connection destination candidate, that is, information such as the communication protocol, IP address, and port number of the connection destination candidate terminal device 2.

[5. Description of Configuration of Content Input Device 4]
Next, the configuration and operation of the content input device 4 will be described with reference to FIG.

  FIG. 20 is a diagram illustrating a schematic configuration example of the content input device 4 in the present embodiment. As the content input device 4, a general server computer can be applied. As shown in FIG. 20, a CPU (Central Processing Unit) 402, a rewritable main storage device 405 that stores (stores) various programs, and the like, A hard disk device 403 that stores various data, a network interface 404 that communicates with the content distribution device 1, the terminal device 2, the connection management device 3, and the like via the network 6, and a keyboard that can input predetermined information The peripheral device control chip 406 that controls input means such as 407 and the mouse 408 and image data from the CPU 402 are received and written to an internal video memory (not shown), and the data written to the video memory is displayed on the display 410. Video chip 40 These various components are connected to each other via a system bus 401.

  In the present embodiment, the CPU 402 and the main storage device 405 constitute a control unit 430. The network interface 404 is connected to the network 6 via the router 10d. This router 10d corresponds to the router 10 shown in FIG.

(Regarding main memory 405)
The main storage device 405 includes an OS program 417 for providing a basic function of the content input device 4 as a computer, and the content distribution device 1 in the first distribution mode and the terminal device 2 in the second distribution mode. A content management program 419 for performing transmission and management of content data, and an identification information list in which content names and content IDs of a plurality of content data input in the first distribution form and the second distribution form are associated with each other. A catalog management program 418 for generating an identification information list and storing it in the identification information list storage area of the hard disk device 403, taking out the identification information list from the identification information list storage area of the hard disk device 403, and transmitting it to the terminal device 2. Etc. are stored, and these are stored in the CPU 4 Read by 2, and functions according to the program by the CPU402 is executed.

  Here, the OS program 417 is read out and executed by the CPU 402, whereby functions related to input / output of the keyboard 407 and mouse 408, and content input device 4 such as memory management such as the main storage device 405 and the hard disk device 403. It is possible to execute the basic functions of a computer. Then, with the OS program 417 being executed by the CPU 402, the above-described catalog management program 418, content management program 419, and the like are executed.

  The OS program 417, catalog management program 418, content management program 419, etc. may be downloaded to the main storage device 405 from a server connected to the network 6, for example, or a CD-ROM or the like. After being recorded on the recording medium, it may be read into the main storage device 405 via a drive of the recording medium.

(About control unit 430)
The control unit 430 includes the CPU 402 and the main storage device 405 as described above, and the CPU 402 reads out and executes the various programs 417 to 419 stored in the main storage device 405, thereby controlling the entire content input device 4. It controls and functions as a content input unit, an identification information list generation unit, an identification information list transmission unit, etc., which will be described later. Further, the hard disk device 403 includes a content data storage area for storing content data to be transmitted and input to the content distribution device 1 in the first distribution form and the content holding terminal device in the second distribution form, and the content distribution device 1 and the second It is composed of an identification information list storage area or the like as identification information list storage means for storing an identification information list related to content data input to a content holding terminal device in a distribution form.

  Here, the identification information list storage means also stores an identification information list including identification information of content data other than the content data to be streamed by the content distribution device 1 as described above. Therefore, content data other than the content data directly distributed in the broadcast form can be acquired in the second distribution form. For example, when the content data is music content, it is possible to acquire music content viewed in the past in the second distribution form.

  The CPU 402 functions as an identification information list generation unit, an identification information list transmission unit, and the like when the catalog management program 418 is executed, and as a content input unit and the like when the CPU 402 executes the content management program 419.

(About content input means)
The content input means transmits content data distributed in the second distribution form to some terminal devices 2 among the plurality of terminal devices 2. Specifically, it operates as follows.

  When there is a content data input instruction by a request from the content distribution apparatus 1 or an operation from the input means such as the keyboard 407 and the mouse 408, the content input means sends the content data corresponding to the input instruction to the hard disk device 403. Retrieve from the content data storage area.

  The content data extracted from the hard disk device 403 is transmitted to the distribution forms of both the first distribution form and the second distribution form by the content input unit and input. However, the content input means may be input to the second distribution form even if the content data is not input to the first distribution form.

  In other words, the content input unit transmits the content data extracted from the hard disk device 403 to the content distribution device 1. The content data transmitted to the content distribution device 1 is streamed to each terminal device 2 in the first distribution form.

  In addition, the content input unit transmits the content data extracted from the hard disk device 403 to several terminal devices 2 in the second distribution form, and functions as a content holding terminal device. The destination terminal device 2 is randomly determined by the content input means.

(Identification information list generation means)
The identification information list generation unit updates the identification information list stored in the identification information list storage area of the hard disk device 403 when content data is input by the content input unit. That is, information that associates the content name and content ID of the content data newly input by the content input means is added to the identification information list.

(Identification information list transmission means)
The identification information list transmission unit transmits the identification information list stored in the identification information list storage unit to the plurality of terminal devices. That is, when there is an identification information list transmission request from the content distribution device 1 or the terminal device 2, the identification information list stored in the identification information list storage area of the hard disk device 403 is transmitted to the requested device.

[6. Description of the configuration of the contact introduction device 5]
Next, the configuration and operation of the contact destination introduction device 5 will be described with reference to FIG.

  FIG. 21 is a diagram illustrating a schematic configuration example of the contact introduction device 5 in the present embodiment. As the contact destination introduction device 5, a general server computer can be applied. As shown in FIG. 21, a CPU (Central Processing Unit) 502, a rewritable main storage device 505 for storing (storing) various programs and the like, Controls input means such as a hard disk device 503 that stores various data, a network interface 504 that communicates with the terminal device 2 via the network 6, and a keyboard 507 and a mouse 508 that can input predetermined information. A peripheral device control chip 506 that receives image data from the CPU 502, writes the image data to an internal video memory (not shown), and displays the data written to the video memory on the display 510. These various components Elements are connected to each other via a system bus 501.

  In the present embodiment, the CPU 502 and the main storage device 505 constitute a control unit 530. The network interface 504 is connected to the network 6 through the router 10e. This router 10e corresponds to the router 10 shown in FIG.

(About the main memory 505)
The main storage device 505 stores an OS program 517 for providing basic functions of the contact introduction device 5 as a computer, location information (such as IP addresses and port numbers) of a plurality of terminal devices 2, and the like. A terminal management program 518 for managing, a contact destination terminal apparatus introduction program 519 for introducing another terminal apparatus 2 to be contacted in response to a request from the terminal apparatus 2 not participating in the second distribution form, etc. Are read out by the CPU 502, and the function according to these programs is executed by the CPU 502.

  Here, the OS program 517 is read out and executed by the CPU 502, whereby functions related to input / output of the keyboard 507 and mouse 508, and contact destination introduction devices such as memory management of the main storage device 505 and the hard disk device 503. The basic function of the computer 5 is made executable. Then, with the OS program 517 being executed by the CPU 502, the above-described terminal management program 518, contact destination terminal device introduction program 519, and the like are executed.

  The OS program 517, terminal management program 518, contact destination terminal device introduction program 519, etc. may be downloaded to the main storage device 505 from, for example, a server connected to the network 6, or a CD- After being recorded on a recording medium such as a ROM, it may be read into the main storage device 505 via a drive of the recording medium.

(About control unit 530)
The control unit 530 includes the CPU 502 and the main storage device 505 as described above, and the CPU 502 reads out and executes various programs 517 to 519 stored in the main storage device 505, whereby the entire contact destination introduction device 5 is read. It performs overall control and functions as terminal device management means, contact destination terminal device introduction means, etc., which will be described later.

  The CPU 502 functions as a terminal management unit or the like when the terminal management program 518 is executed, and the contact destination terminal device introduction unit or the like as the CPU 502 executes a contact destination terminal device introduction program 519.

(About terminal management means)
Upon receiving a registration request for the second distribution form from the terminal device 2, the terminal management means registers the IP address, which is the location information of the terminal device 2, in the terminal management database 515. The location information of the terminal device 2 is included in the registration request from the terminal device 2, and the location information is acquired from the registration request.

(Contacting terminal device introduction means)
When the contact destination terminal device introduction means receives a registration request for the second distribution form from the terminal device 2, the terminal device 2 that made the registration request transmits a participation message from the terminal device 2 registered in the terminal management database 515. The terminal device 2 to be selected is selected.

  The contact destination terminal device introduction means retrieves the location information of the selected terminal device 2 from the terminal management database 515 and transmits it to the terminal device 2 that made the registration request.

[7. Operation of Content Distribution System S]
Hereinafter, detailed operations of the content distribution device 1, the terminal device 2, the connection management device 3, the content input device 4, and the contact destination introduction device 5 will be described more specifically with reference to flowcharts.

(Description of processing flow of content distribution apparatus 1)
First, a more specific operation of the content distribution apparatus 1 will be described with reference to FIG. FIG. 22 is a flowchart showing the entire processing in the content distribution apparatus 1. The following processes are executed by the control unit 130 of the content distribution apparatus 1 functioning as the above-described means.

  First, as shown in FIG. 22, when the power of the content distribution apparatus 1 is turned on, in the content distribution apparatus 1, the CPU 102 initializes access permission of the main storage device 105 and the hard disk device 103, initializing the work area, and the like. A setting process is executed (step S100), the programs 115 to 120 are executed by the CPU 102, the function as the control unit 130 is operated, and the process proceeds to step S101.

  In step S101, the control unit 130 in the content distribution device 1 requests the content input device 4 for content data to be broadcast in the first distribution form, and the content data transmitted from the content input device 4 in response to the request. It is stored in the broadcast content storage area in the hard disk device 103.

  In step S102, the control unit 130 in the content distribution apparatus 1 determines whether or not a broadcast start request or stop request has been received from the broadcast operator. Here, whether or not there is a broadcast start request or stop request from the broadcast operator is whether or not a broadcast start operation has been performed from the input means such as the keyboard 107 or the mouse 108 or the input means such as the keyboard 107 or the mouse 108. From this, it is determined whether or not a broadcast stop operation has been performed. Here, the broadcast operator means an operator that manages content distribution according to the first distribution form and the second distribution form, but the content distribution according to the first distribution form and the second distribution form are different operators. You may make it perform by.

  In this process, if it is determined that a broadcast start request has been received from the broadcast operator (step S102: Yes), the control unit 130 divides the content data retrieved from the hard disk device 103 into content packets while dividing the content data into predetermined capacity. It stores and prepares to transmit this content packet to the terminal device 2 logically connected downstream via the network 6. On the other hand, similarly, when it is determined that there is a broadcast stop request from the broadcast operator (step S102: Yes), the control unit 130 performs a content packet to the terminal device 2 logically connected downstream. Is stopped (step S103), and the process proceeds to step S130.

  On the other hand, in step S102, when the control unit 130 determines that there is no broadcast start request from the broadcast operator (step S102: NO), the process proceeds to step S110.

  In step S <b> 110, the control unit 130 in the content distribution device 1 determines whether a request for opening or disconnecting a session has been received from the terminal device 2. In this process, the control unit 130 in the content distribution apparatus 1 determines whether or not there is a session establishment or disconnection request from the terminal apparatus 2 via the network 6.

  In this process, if the control unit 130 determines that there is a request for opening a session (step S110: YES), it establishes a connection with the terminal device 2 (step S111), and there is a request for disconnecting the session. If it is determined (step S110: YES), the connection with the terminal device 2 is disconnected (step S111), and the process proceeds to step S112. That is, the control unit 130 performs control to change and set the connection state of the terminal device 2 in response to a request from the terminal device 2.

  If it is determined in step S110 that there is a session establishment request (step S110: YES), the control unit 130 transmits content data to the terminal device 2 logically connected downstream of the content distribution device 1 in step S112. Send streaming. That is, the content packet generated in step S103 is sequentially transmitted to the terminal device 2 logically connected downstream via the network 6. If it is determined that a session disconnection request has been made (step S110: YES), the control unit 130 performs streaming transmission of content data to the terminal device 2 logically connected downstream of the content distribution device 1. Stop. That is, the transmission of the content packet generated in step S103 is stopped (step S112). When the process of step S112 ends, the control unit 130 moves the process to step S120.

  On the other hand, in step S110, when it is determined that neither the session opening nor the disconnection is requested from the terminal device 2 (step S110: NO), the control unit 130 moves the process to step S120.

  In step S120, the control unit 130 determines whether or not the power is off. If it is determined that the power is off (step S120: YES), the process ends. If it is determined that there is not (step S120: NO), the process is repeated from step S102.

(Description of processing flow of terminal device 2)
Next, a more specific operation of the terminal device 2 will be described with reference to the flowcharts of FIGS. 23 to 32 are flowcharts showing processing in the terminal device 2. The following processes are executed by the control unit 230 of the terminal device 2 functioning as the above-described means.

  As shown in FIG. 23, when the power of the terminal device 2 is turned on, the CPU 202 of the terminal device 2 executes an initial setting operation such as initialization of access permission and work area reservation of the main storage device 205 and the hard disk device 203. Each program 215 to 219, 221 is put into an execution state by the CPU 202 and the function as the control unit 230 is operated (step S200), and then the process proceeds to step S201.

  In step S <b> 201, the control unit 230 acquires an identification information list from the content input device 4. The acquisition of the identification information list is performed when the control unit 230 requests the content input device 4 for an identification information list and receives the identification information list transmitted in response to the request.

  This identification information list is information in which names of a plurality of content data that can be acquired in the second distribution form and content IDs are associated with each other as described above, and the control unit 230 acquires this identification information list and incorporates it. By displaying on the display 210, the user of the terminal device 2 can acquire content data in the second distribution form by operating the remote controller 208 or the like.

  Next, after performing the initial channel setting process in step S202, the control unit 230 moves the process to step S203. The process of step S202 is the process of S240 to S247 in FIG. 26 and will be described in detail later.

  In step S203, the control unit 230 determines whether or not there has been a channel selection instruction from the user. Whether or not there has been a channel selection instruction from the user is determined by whether or not a channel selection instruction has been made from channel selection means such as the remote control 208.

  In this process, if the control unit 230 determines that there is a channel selection instruction from the user (step S203: YES), the control unit 230 proceeds to a channel change process (step S204). The process of step S204 is the process of S250 to S254 and S260 to S267 in FIGS. 27 and 28, and will be described in detail later.

  On the other hand, if it is determined in step S203 that there has been no channel selection instruction from the user (step S203: NO), the control unit 230 determines whether an upstream device candidate has been received from the connection management device 3 (step S205). ). That is, in response to the connection destination candidate introduction request made in the channel change processing in step S204, it is determined whether or not the connection destination candidate of the upstream device has been notified from the connection management device 3.

  In this process, if it is determined that the upstream device connection destination candidate is received from the connection management device 3 (step S205: YES), the control unit 230 selects the upstream device connection destination candidate notified from the connection management device 3 from the above. After selecting one upstream candidate connection destination device (step S206), the process proceeds to step S207.

  In step S207, the control unit 230 makes a logical connection via the network 6 to the upstream device of the selected connection destination candidate. The logical connection to the upstream device is executed by the control unit 230 making a connection request to the upstream device via the network 6. When the process of step S207 ends, the control unit 130 moves the process to step S208.

  Thereafter, in step S208, the control unit 230 requests the upstream device for streaming distribution of content data via the network 6, and the process proceeds to step S209.

  In step S209, the control unit 230 transmits a topology participation report to the connection management device 3 via the network 6.

  On the other hand, if it is determined in step S205 that no upstream device candidate has been received from the connection management device 3 (step S205: NO), the control unit 230 determines whether a content packet has been received from the upstream device (step S205). S210).

  In this process, when the control unit 230 determines that the content packet has been received from the upstream device (step S210: YES), the content data is extracted from the content packet received from the upstream device, stored in the ring buffer area 220, and further The content data is extracted and transferred to the downstream terminal device 2 as a content packet (step S211).

  Thereafter, the control unit 230 determines whether or not the content packet received from the upstream device is a content packet of the selected channel (step S212). Whether or not it is a content packet of the selected channel is determined by the control unit 230 based on the header portion of the content packet received from the upstream device via the network 6. That is, the control unit 230 determines whether the channel information included in the header portion of the content packet is a selected channel.

  Here, the selected channel means the latest channel selected last by a channel selection button or the like among a plurality of participating channels.

  In this process, when it is determined that the content packet received from the upstream device is the content packet of the selected channel (step S212: YES), the control unit 230 acquires and reproduces the content data stored in the ring buffer area 220. (Step S213). The reproduction of the content packet is realized by operating the sound source chip 211 and the video chip 209. The content packet at the reproduction time is sequentially extracted from the content data stored in the ring buffer area 220, and a predetermined packet is obtained. Content data format (for example, Wave format) and input to the sound source chip 211 or the video chip 209 to reproduce the content.

  On the other hand, when determining that the content packet received from the own upstream device is not the content packet of the selected channel (step S212: NO), the control unit 230 does not perform the process of step S213.

  If it is determined in step S210 that the content packet has not been received from the upstream device (step S210: NO), the control unit 230 determines whether there is a streaming distribution start / stop request (step S214). Whether there is a streaming distribution start / stop request, whether a streaming distribution start request transmitted from the downstream terminal apparatus 2 has been received, or a streaming distribution stop request transmitted from the downstream terminal apparatus 2 Is determined by whether or not the message is received.

  In this process, when the control unit 230 determines that there is a streaming distribution start request (step S214: YES), the control unit 230 starts transferring the content packet to the downstream device that has made the streaming distribution start request (step S214: YES). Step S215). Further, when the control unit 230 determines that there is a request for stopping streaming distribution (step S214: YES), the control unit 230 stops the transfer of the content packet to the downstream device that has made the streaming distribution stop request (step S215). ).

  This process sets whether or not to transfer the content packet in step S211, and if it is determined that there is a request to start streaming distribution, the setting is performed to transfer the content packet to the downstream device, and the streaming distribution is stopped. If it is determined that there is a request, the setting is made to stop the transfer of the content packet to the downstream device.

  On the other hand, if it is determined in step S214 that there is no request for starting / stopping streaming delivery (step S214: NO), the control unit 230 determines whether a content registration message has been received (step S216). Whether or not a content registration message has been received is determined by whether or not the content registration message transmitted from the content holding terminal device via the network 6 has been received by the terminal device 2 itself.

  In this process, if it is determined that the content registration message has been received (step S216: YES), the control unit 230 stores the location information of the content holding terminal device included in the received content registration message in the index table 222 of the main storage device 205, and A content ID of content data held by the content holding terminal device is associated and added to the index table 222 (step S217).

  Thereafter, the control unit 230 determines whether or not the terminal device 2 is a root terminal device (step S218). Whether or not the terminal device 2 is a root terminal device is determined based on the destination identification information of the received content registration message and the routing table 223.

  In this process, when the control unit 230 determines that the terminal device 2 is not a root terminal device (step S218: NO), the control unit 230 transfers the content registration message to another terminal device 2 based on the routing table 223 (step S219). ). On the other hand, when determining that the terminal device 2 is the root terminal device (step S218: YES), the control unit 230 does not perform the process of step S219.

  If it is determined in step S216 that a content registration message has not been received (step S216: NO), the control unit 230 determines whether a content deletion message has been received (step S220). Whether or not a content deletion message has been received is determined based on whether or not a content deletion message transmitted from the content holding terminal device has been received via the network 6.

  In this process, when the control unit 230 determines that the content deletion message has been received (step S220: YES), the index information (content ID, location location of the content holding node device, etc.) corresponding to the content deletion message from the index table 222. (Step S221), the process proceeds to step S218.

  If it is determined in step S220 that the content deletion message has not been received (step S220: NO), the control unit 230 determines whether or not content data to be input has been received (step S222).

  In this process, when it is determined that the content data input from the content input device 4 has been received (step S222: YES), the control unit 230 performs an input content reception process (step S223). This input content reception process is the process of S275 to S278 in FIG. 29 and will be described in detail later.

  If it is determined in step S222 that the content data to be input has not been received (step S222: NO), the control unit 230 determines whether there is a content purchase instruction from the user (step S224). Whether or not there is a content purchase instruction from the user is determined based on whether or not a content purchase instruction is operated from input means such as the remote control 208.

  In this process, when the control unit 230 determines that a download request operation by the user, that is, a content purchase instruction has been made (step S224: YES), the content purchase process is performed (step S225). This content purchase processing is the processing of S280 to S289 in FIG. 30, and will be described in detail later. For example, when the user performs a predetermined operation on the remote control 208 in a state where a screen as shown in FIG. 16 is displayed on the built-in display 210, the download request is operated by the user. Determine that it was done.

  If it is determined in step S224 that there is no content purchase instruction from the user (step S224: NO), the control unit 230 determines whether or not there is a content download request from another terminal device 2 (step S226). This content download request is a request for batch transmission of the entire content data in the second distribution form, and when the terminal device 2 is a content holding terminal device or a cache device that caches content data related to a content download request, It is determined that a content download request has been received.

  In this process, when the control unit 230 determines that there is a content download request from another terminal device 2 (step S226: YES), the control unit 230 retrieves content data corresponding to the content download request from the hard disk device 203 and makes a content download request. The extracted content data is transmitted to the other terminal device 2 (step S227).

  In this process, when the control unit 230 determines that there is no content download request from another terminal device 2 (step S226: NO), the control unit 230 determines whether the purchased content data has been downloaded (step S228). Whether or not the purchased content data has been downloaded is determined based on whether or not the content data has been received from the content holding terminal device that requested the download when the user requested a download request, that is, when a content purchase instruction was issued.

  In this process, if it is determined that the purchase content data has been downloaded (step S228: YES). The downloaded purchased content data is stored in the hard disk device 203 and stored (step S229). The content data is divided into a predetermined capacity from the content holding terminal device and transmitted as content packets, and the control unit 230 receives each content packet and stores it in the hard disk device 203.

  When the process of step S229 ends, the control unit 230 transmits an upstream device connection destination introduction request regarding the zapping countermeasure channel to the connection management device 3 (step S230). This process is a process for re-joining the zapping countermeasure channel that has left in step S284 described later.

  If it is determined in step S228 that purchased content data has not been downloaded (step S228: NO), the control unit 230 determines whether or not a content search message has been received (step S231). Whether or not a content search message has been received is determined based on whether or not a content search message transmitted from the request terminal device has been received from the terminal device 2 via the network 6.

  In this process, when the control unit 230 determines that a content search message has been received (step S231: YES), the control unit 230 performs a content search process in step S232. This content search process is the process of S290 to S294 in FIG. 32 and will be described in detail later.

  If it is determined in step S231 that a content search message has not been received (step S231: NO), the control unit 230 determines whether or not content holding terminal device information has been received (step S233). When the content holding terminal device information is information including the location information of the content holding terminal device and it is determined that the content holding terminal device information has been received (step S233: YES), the control unit 230 acquires the acquired content holding terminal device. Based on the location information, the content holding terminal device is requested to collectively transmit the entire content data (step S234).

  If it is determined in step S233 that the content holding terminal device information has not been received (step S233: NO), the control unit 230 determines whether or not a participation message for the second distribution form has been received (step S235). ).

  In this process, when the control unit 230 determines that the participation message for the second distribution form has been received (step S235: YES), the control unit 230 transmits the possessed table information to the terminal device that has transmitted the participation message (step S235). S236). That is, out of the table information of the routing table 223, the table information of the lowest level among the levels that do not match the destination identification information of the participation message is extracted from the routing table 223 and transmitted to the terminal device 2 that transmitted the participation message.

  Thereafter, the control unit 230 determines whether or not the terminal device 2 is a root terminal device (step S237). Whether or not the terminal device 2 is a root terminal device is determined based on the destination identification information of the received participation message and the routing table 223.

  In this process, when the control unit 230 determines that the terminal device 2 is not the root terminal device (step S237: NO), the control unit 230 transfers the participation message to another terminal device 2 based on the routing table 223 (step S238). . On the other hand, when determining that the terminal device 2 is the root terminal device (step S237: YES), the control unit 230 does not perform the process of step S238.

  Next, the initial channel setting process in S202 will be specifically described with reference to the flowchart of FIG.

  As shown in FIG. 26, the control unit 230 first acquires a viewing channel from the final viewing channel storage file (step S240). In this final viewing channel storage file, a channel (hereinafter referred to as “final viewing channel”) viewed immediately before the terminal device 2 is turned off is stored in the hard disk device 203 by the control unit 230 and stored. It is. In the hard disk device 203, an area for storing a final viewing channel storage file is secured.

  Next, the control unit 230 determines whether or not the final viewing channel has been acquired (step S241). Whether or not the final viewing channel has been acquired is determined based on whether or not the final viewing channel storage file is stored in the hard disk device 203. That is, when the last viewing channel saving file is stored, the last viewing channel is acquired from the file.

  In this process, when it is determined that the final viewing channel cannot be acquired (step S241: NO), the control unit 230 sets a channel to be viewed first as a default channel (here, channel ch1).

  On the other hand, when it is determined that the final viewing channel can be acquired (step S241: YES), or when the viewing channel is set to channel ch1 in step S242, the control unit 230 sets the first viewing channel as the final viewing channel or channel ch1. The connection management apparatus 3 is requested of the connection destination candidates of the upstream apparatus related to the viewing channel (step S243), and the process proceeds to step S244.

  In step S244, the control unit 230 requests the connection management apparatus 3 for a connection destination candidate of the upstream apparatus related to a channel smaller by 1 than the channel number of the viewing channel, and proceeds to the process of step S245.

  In step S245, the control unit 230 requests the connection management apparatus 3 for a connection destination candidate of the upstream apparatus related to a channel smaller by 2 than the channel number of the viewing channel, and proceeds to the process of step S246.

  In step S246, the control unit 230 requests the connection management apparatus 3 for an upstream device connection destination candidate for a channel larger by 1 than the channel number of the viewing channel, and proceeds to the process of step S247.

  In step S247, the control unit 230 requests the connection management apparatus 3 for a connection destination candidate of the upstream apparatus regarding a channel that is 2 larger than the channel number of the viewing channel.

  As described above, in the initial channel setting process, the final viewing channel or the default channel is used as a viewing channel and a connection destination candidate for the channel is requested, and connection destination candidates for channels in the range of ± 2 from the channel number of the viewing channel. To request. Connection destination candidates notified from the connection management apparatus 3 in response to this connection destination candidate request are received in step S205 described above. For example, in the case where all channels are ch1 to ch10, if the final viewing channel is ch1, the channel for requesting the connection destination candidate is ch2, ch2 (ch1 + 1), ch3 (ch1 + 2), ch9 (ch1-1). , Ch10 (ch1-2).

  Next, the initial channel processing in S204 will be specifically described with reference to the flowchart of FIG. 27 and the flowchart of FIG.

  As shown in FIG. 27, first, the control unit 230 determines whether or not the “+” button has been pressed (step S250). Whether or not the “+” button has been pressed depends on, for example, whether or not the “+” button has been pressed by operating the remote control 208 or the like while the channel selection screen displayed on the built-in display 210 is displayed. To be judged. FIG. 15 shows an example of a channel selection screen displayed on the built-in display 210 of the terminal device 2. The channel selection button 22 corresponds to the “+” button, and the channel selection button 23 corresponds to the “−” button. The display frame 21 displays content that is played back by the streaming playback means.

  In this process, when it is determined that the “+” button has been pressed (step S250: YES), the control unit 230 executes “channel change process (+)” in step S251.

  This process consists of the process of step S260-S263, as shown to Fig.28 (a). First, the control unit 230 requests the upstream device that is the content supply source terminal in the zapping countermeasure channel that is smaller by 2 than the channel number of the current viewing channel to stop the content stream (step S260). That is, the content distribution apparatus 1 that is logically connected to the own terminal apparatus 2 and performs streaming distribution to the own terminal apparatus 2 in the first distribution form with respect to the zapping countermeasure channel that is smaller by 2 than the channel number of the current viewing channel. Alternatively, another terminal apparatus 2 is requested via the network 6 to stop the streaming distribution of the content data.

  Thereafter, the control unit 230 leaves the topology of the zapping countermeasure channel that is smaller by 2 than the channel number of the current viewing channel (step S261). That is, the control unit 230 disconnects the session with the upstream device related to the zapping countermeasure channel that is smaller by 2 than the channel number of the current viewing channel, and if there is a downstream device related to the zapping countermeasure channel, By disconnecting the session, the channel is withdrawn from the topology of the zapping countermeasure channel, and the process proceeds to step S262.

  In step S262, the control unit 230 requests the connection management apparatus 3 to set a channel that is 3 larger than the channel number of the current viewing channel as a zapping countermeasure channel, and request a connection destination candidate of an upstream apparatus related to this zapping countermeasure channel. Then, the process proceeds to step S263.

  In step S263, the control unit 230 switches the viewing channel to a channel obtained by adding +1 to the channel number of the current viewing channel. For example, if the current viewing channel is channel ch5, channel ch6 is set as the viewing channel.

  On the other hand, in the process of step S250 of FIG. 27, when determining that the “+” button has not been pressed (step S251: NO), the control unit 230 determines whether the “−” button has been pressed (step S252). ).

  In this process, if the control unit 230 determines that the “−” button has been pressed (step S252: YES), it executes “channel change process (−)” in step S253.

  As shown in FIG. 28B, this process includes steps S264 to S267. First, the control unit 230 requests the upstream device, which is a content supply source terminal in the channel for countermeasures against zapping, which is 2 larger than the channel number of the current viewing channel, to stop the content stream (step S264). That is, the content distribution apparatus 1 that is logically connected to the own terminal apparatus 2 and performs streaming distribution to the own terminal apparatus 2 in the first distribution form with respect to the zapping countermeasure channel that is larger by 2 than the channel number of the current viewing channel. Alternatively, another terminal apparatus 2 is requested via the network 6 to stop the streaming distribution of the content data.

  Thereafter, the control unit 230 leaves the topology of the zapping countermeasure channel that is larger by 2 than the channel number of the current viewing channel (step S265). That is, the control unit 230 disconnects the session with the upstream device related to the zapping countermeasure channel that is larger by 2 than the channel number of the current viewing channel, and if there is a downstream device related to the zapping countermeasure channel, By disconnecting the session, the topology of the channel for countermeasures against zapping is withdrawn, and the process proceeds to step S266.

  In step S266, the control unit 230 requests the connection management apparatus 3 to set a channel that is smaller than the channel number of the current viewing channel by 3 as a zapping countermeasure channel, and request a connection destination candidate of an upstream apparatus related to this zapping countermeasure channel. Thus, the process proceeds to step S267.

  In step S268, the control unit 230 switches the viewing channel to a channel obtained by adding -1 to the channel number of the current viewing channel. For example, if the current viewing channel is channel ch5, channel ch4 is set as the viewing channel.

  When the “channel change process (+)” process in step S251 shown in FIG. 28A is completed, or the “channel change process (−)” process in step S253 shown in FIG. Then, the process proceeds to step S254 shown in FIG.

  In this process, the viewing channel number is written in the final viewing channel storage file. That is, the viewing channel number of the last viewing channel storage file stored in the hard disk device 203 is overwritten with the channel number of the viewing channel switched in step S263 or step S267.

  As described above, in the channel change process, when the viewing channel switching operation is performed by the user, the viewing channel is switched and the zapping countermeasure channel switching process is performed.

  In the present embodiment, the channel within the range of ± 2 of the channel number of the viewing channel is set as the zapping countermeasure channel, but a zapping countermeasure channel may be set for each viewing channel number. For example, if the viewing frequency is detected for each channel and the channel with low viewing frequency is the viewing channel, the number of channels for preventing zapping is increased, and if the channel with high viewing frequency is the viewing channel, the channel for preventing zapping By reducing the number of channels, it is possible to efficiently set the zapping countermeasure channel.

  Next, the input content reception process in S223 will be specifically described with reference to FIG.

  First, the control unit 230 of the terminal device 2 stores and stores the input content data received in step S222 in the content data storage area of the hard disk device 203 (step S275).

  Thereafter, the control unit 230 determines whether or not the own terminal device 2 is a root terminal device (step S276). Whether or not the terminal device 2 is a root terminal device is determined by calculating the content name of the received content data using a predetermined hash function and determining whether or not the terminal device having the content ID is its own terminal device. .

  In this process, when the control unit 230 determines that the terminal device 2 is not a root terminal device (step S276: NO), the content registration message is transmitted to the other terminal devices 2 via the network 6 based on the routing table 223. Transmit (step S278). On the other hand, when determining that the terminal device 2 is the root terminal device (step S276: YES), the control unit 230 adds and registers the content ID and the location information of the terminal device to the index table 222 (step S277). .

  As described above, in the input content reception process, the content data input from the content input device 4 is stored and stored in the hard disk device 203 and registered in the index table of the root terminal device.

  Next, the content purchase processing in S225 will be specifically described with reference to FIG.

  First, the control unit 230 of the terminal device 2 acquires a content ID to be purchased from the identification information list (step S280). That is, the content ID related to the content data determined to have been instructed to purchase content by the user in step S224 is acquired from the identification information list acquired from the content input device 4.

  Next, the control unit 230 determines whether or not the complete version of the purchased content data exists in the ring buffer area 220 (step S281). Whether or not the complete version of the purchased content data exists is determined based on whether or not the entire content data determined to have been instructed to purchase the content by the user in step S225 is stored in the ring buffer area 220. Note that the content data currently being viewed in the broadcast format is not stored entirely in the ring buffer area 220, and the determination in step S281 is YES for content data that has already been viewed in the broadcast format, This is limited to that accumulated in the ring buffer area 220.

  In this process, if it is determined that the complete version of the purchased content data exists in the ring buffer area 220 (step S281: YES), the control unit 230 stores the purchased content data in the content data storage area of the hard disk device 203. (Step S282). Since the content data stored in the ring buffer area 220 is content data for streaming playback, the content data stored in the ring buffer area 220 is converted into a purchase content format (download format) in the process of step S282. After that, it is stored in the content data storage area of the hard disk device 203. If it is determined that the complete version of the purchased content data exists in the ring buffer area 220 (step S281: YES), the control unit 230 sends the content stream to the upstream device that is the content supply source terminal of the zapping countermeasure channel. Is not requested, and no withdrawal from the topology of the anti-zapping channel is performed. That is, the control unit 230 does not disconnect the session with the upstream device related to the zapping countermeasure channel.

  On the other hand, if it is determined in step S281 that the complete version of the purchased content data does not exist in the ring buffer area 220 (step S281: NO), the control unit 230 is the content supply source terminal of all the zapping countermeasure channels. The upstream apparatus is requested to stop the content stream (step S283). That is, with respect to all the zapping countermeasure channels, to the content distribution apparatus 1 or other terminal apparatus 2 that is logically connected to the own terminal apparatus 2 and performs streaming distribution to the own terminal apparatus 2 in the first distribution form, A request is made via the network 6 to stop the streaming distribution of the content data.

  Thereafter, the controller 230 leaves the topology of all the zapping countermeasure channels (step S284). That is, the control unit 230 disconnects the session with the upstream device regarding all the zapping countermeasure channels, and if there is a downstream device regarding the zapping countermeasure channel, the control unit 230 disconnects the session with the downstream device, thereby The channel topology is withdrawn, and the process proceeds to step S285.

  The process of step S285 is a process of participating in the second distribution form, and the process of step S285 is the process of S270 to S274 in FIG. 31, and will be described in detail later.

  When the participation process to the second distribution form in step S285 ends, the control unit 230 determines whether or not the content ID exists in the index table 222 (step S286).

  In this process, if it is determined that the content ID exists in the index table 222 (step S286: YES), the control unit 230 acquires the location information of the content holding terminal device from the index table 222 (step S287), and step S288. Move on to processing.

  In step S288, the control unit 230 transmits a content transmission request to the location information of the content holding terminal device acquired from the index table 222. That is, the control unit 230 makes a download transmission request to the content holding terminal device.

  If it is determined that the content ID does not exist in the index table 222 (step S286: NO), the control unit 230 transfers a message to the next terminal device via the network 6 (step S289). That is, the control unit 230 transfers the content search message to another terminal device 2 via the network 6 based on the routing table 223.

  Here, the participation process in the second distribution form in S285 will be specifically described with reference to FIG.

  First, the control unit 230 of the terminal device 2 requests contact destination information from the contact destination introduction device 5 via the network 6 (step S270). In response to the request for contact destination information, the contact destination information transmitted from the contact destination introduction apparatus 5 via the network 6 is received via the network interface 204 (step S271).

  The received contact destination information includes the location information of the contact destination terminal device, and the control unit 230 sends a participation message to the contact destination terminal device included in the received contact destination information via the network 6. (Step S272). This participation message uses the identification information of the terminal device as destination identification information.

  The participation message transmitted in this way is sequentially transferred from the terminal device 2 that is the contact destination, and reaches the terminal device 2 at a position where it cannot be transferred. Then, table information for each level is received from a plurality of terminal devices that have received the participation message (step S273).

  Next, the control part 230 produces | generates a routing table based on the several table information received in this way (step S274).

  As described above, when a purchase request is requested, the terminal device 2 participates in the second distribution form, so that the content can be transmitted and received between the plurality of terminal apparatuses 2 in the second distribution form. ing.

  As described above, in the content purchase processing, when a content purchase operation is performed by the user, the tree-like hierarchical structure of all the zapping countermeasure channels is withdrawn, and then the content data is acquired in the second distribution form. Yes. Therefore, when content data is acquired in the second distribution form, the tree-like hierarchical structure of the zapping countermeasure channel is withdrawn, and therefore there is no influence of the zapping countermeasure channel when acquiring content data in the second distribution form.

  In the case where the second distribution form does not significantly affect the acquisition of content data instead of leaving the tree-like hierarchical structure of all the zapping countermeasure channels, only a part of the zapping countermeasure channels is in a tree form. You may make it leave the hierarchical structure.

  When withdrawing from a tree-like hierarchical structure of only a part of the zapping countermeasure channels, the control unit 230 may set a zapping countermeasure channel to be withdrawn for each viewing channel number.

  For example, the control unit 230 detects the viewing frequency for each channel, and when the channel with low viewing frequency is the viewing channel, the control unit 230 reduces the number of zapping countermeasure channels to be withdrawn, and the channel with high viewing frequency is the viewing channel. In this case, the number of zapping countermeasure channels to be withdrawn can be increased.

  Further, the control unit 230 may set a zapping countermeasure channel to be withdrawn according to the acquisition status of the content data in the second distribution form. In this case, the control unit 230 withdraws from some of the zapping countermeasure channels before acquiring the content data in the second distribution form, and then acquires the content data acquisition state (for example, the second distribution form) in the second distribution form. The zapping countermeasure channels to be withdrawn are increased or decreased in accordance with the content data reception speed in the form. For example, the zapping countermeasure channels to be withdrawn are increased / decreased so that the reception speed of the content data in the second distribution form falls within a predetermined speed range.

  Next, the content search processing in S232 will be specifically described with reference to FIG.

  First, the control unit 230 of the terminal device 2 acquires a content ID from the content search message received in step S231 (step S290).

  Next, the control unit 230 determines whether or not the content ID acquired from the content search message exists in the index table 222 (step S291).

  In this process, when the control unit 230 determines that the content ID acquired from the content search message exists in the index table 222 (step S291: YES), the location information of the content holding terminal device is acquired from the index table 222 (step S292). ), The process proceeds to step S293.

  In step S293, the control unit 230 transmits the location information of the content holding terminal device acquired from the index table 222 to the request terminal device via the network 6.

  On the other hand, when it is determined in step S291 that the content ID acquired from the content search message does not exist in the index table 222 (step S291: NO), the control unit 230 sends a message to the next terminal device via the network 6. Transfer (step S294). That is, the control unit 230 transfers the content search message to another terminal device 2 via the network 6 based on the routing table 223.

  As described above, even when the user of the terminal device 2 switches the channel while viewing the content that is stream-distributed in a broadcast form from the content distribution device, the user receives the content of the switching destination channel as a countermeasure against zapping. Therefore, the content data at the switching destination can be viewed immediately. Moreover, when the content is downloaded in the P2P grid type distribution form, which is the second distribution form, the communication band is reserved for downloading the contents according to the second distribution form because it is withdrawn from the zapping countermeasure channel. it can.

  Further, the terminal device 2 in the present embodiment temporarily caches content data distributed in a broadcast form in a ring buffer area, and when the content data to be purchased is stored in the ring buffer area, the ring buffer The content data stored in the area can be purchased.

  Accordingly, it is possible to shorten the content data purchase process compared to newly acquiring content data in the P2P grid type distribution form. By increasing the capacity of the ring buffer area, it is possible to cache a large amount of content data distributed in broadcast form, so that the download time can be shortened for users who often download the content data after viewing it. Is big.

(Description of processing flow of connection management device 3)
Next, a more specific operation of the connection management device 3 will be described with reference to FIG. FIG. 33 is a flowchart showing the entire processing in the connection management device 3. The following processes are executed by the control unit 330 of the connection management device 3 functioning as each unit described above.

  When the power of the connection management device 3 is turned on, the CPU 302 of the connection management device 3 executes initial setting operations such as initialization of access permission and work area reservation of the main storage device 305 and the hard disk device 303, and each program 317- 320 is set to an execution state by the CPU 302 and the function as the control unit 330 is operated (step S300), and then the process proceeds to step S301.

  In step S <b> 301, the control unit 330 determines whether or not there is a participation request from the terminal device 2. In this process, the control unit 330 determines whether or not a request for participation in the first distribution form from the terminal device 2 has been received via the network 6. The participation request from the terminal device 2 includes channel information that the terminal device 2 wants to participate in the first distribution form.

  In this process, when the control unit 330 determines that a request to participate in the first distribution form has been received from the terminal device 2 (step S301: YES), the location information of the terminal device 2 included in the received participation request is stored in the hard disk device. Is registered in the terminal management database 314 (step S302).

  On the other hand, if it is determined in step S301 that a request for participation in the first distribution form has not been received from the terminal device 2 (step S301: NO), the control unit 330 has received a registration request from the content distribution device 1 or not. Is determined (step S310).

  If it is determined in step S310 that the registration request from the content distribution apparatus 1 has been received (step S310: YES), the control unit 330 sends the location information of the content distribution apparatus 1 included in the received registration request to the terminal management database 314. Registration is performed (step S311).

  Next, the control unit 330 registers new channel information in the topology database 315. That is, a topology table for a new channel is generated in the topology database 315 (step S312).

  If it is determined in step S310 that the registration request from the content distribution device 1 has not been received (step S310: NO), the control unit 330 has received a connection destination introduction request from the terminal device 2 via the network 6. Is determined (step S320).

  If it is determined in step S320 that the connection destination introduction request has been received from the terminal device 2 via the network 6 (step S320: YES), the control unit 330 determines a connection destination candidate for the channel related to the connection destination introduction request from the topology database 315. The terminal device 2 or the content distribution device 1 is selected (step S321).

  The control unit 330 of the connection management device 3 sends back and notifies the connection destination candidates selected in this way via the network 6 to the terminal device 2 that has made the connection destination introduction request (step S322).

  If it is determined in step S320 that the connection destination introduction request has not been received from the terminal device 2 (step S320: NO), the control unit 330 determines whether or not there has been a topology participation report from the terminal device 2 (step S330). . Whether or not a topology participation report has been received from the terminal device 2 is determined by whether or not a topology participation report has been received from the terminal device 2 via the network 6.

  If it is determined in step S330 that there is a topology participation report from the terminal device 2 (step S330: YES), the control unit 330 extracts location information of the terminal device 2 included in the topology participation report, and updates the topology database 315. Is performed (step S331). That is, the control unit 330 registers the topology change in the topology database 315.

  When the processing of steps S302, S312, S322, and S331 is completed, or when it is determined in step S330 that there is no topology participation report from the terminal device 2 (step S330: NO), the control unit 330 performs the service of the connection management device 3. It is determined whether or not an end operation has been performed (step S340). If it is determined that the service termination operation has not been performed (S340: NO), the processing from step S301 is repeated, and if it is determined that the service termination operation of the connection management device 3 has been performed (S340: YES), the processing is terminated. To do.

(Description of processing flow of content input device 4)
Next, a more specific operation of the content input device 4 will be described with reference to FIG. FIG. 34 is a flowchart showing the entire processing in the content input device 4. The following processes are executed by the control unit 430 of the content input device 4 functioning as the above-described means.

  When the power of the content input device 4 is turned on, the CPU 402 of the content input device 4 executes an initial setting operation such as initialization of access permission and work area reservation of the main storage device 405 and the hard disk device 403, and each program 417- After 419 is set to the execution state by the CPU 402 and the function as the control unit 430 is operated (step S400), the process proceeds to step S401.

  In step S401, the control unit 430 determines whether there is a content input instruction (step S401). Here, whether or not there is a content input instruction is determined by whether the control unit 430 determines whether or not a content input operation has been performed from an input unit such as a keyboard 407 or a mouse 408, or from the content distribution apparatus 1 in step S410 described later. Judgment is made based on whether or not there is a request for transmission of content data. This content input instruction is performed by specifying content data by the name of the content.

  In this process, when it is determined that there is a content input instruction (step S401: YES), the control unit 430 stores the content ID corresponding to the content data specified by the content input instruction in the management table stored in the hard disk device 403. After storing (step S402), the process proceeds to step S403. The management table stores a plurality of content data stored in the hard disk device 403 in association with content IDs. Further, for each content data stored in the hard disk device 403, the content distribution device 1 and the content holding terminal are stored. A flag indicating whether or not it is input to the apparatus is stored in association with each content. The flag includes an uninserted flag (flag value is “0”) and an input flag (flag value is “1”).

  In step S403, the control unit 430 updates the identification information list and moves the process to step S404. The identification information list is updated by additionally storing the content ID and the content name corresponding to the content data specified by the content input instruction in the identification information list stored in the hard disk device 403.

  In step S404, the control unit 430 allows the content data specified by the content input instruction to be distributed in the second distribution form, so that the terminal device 2 serving as the content holding terminal device for the content data specified by the content input instruction. 1 or more are determined at random. The control unit 430 transmits the content data specified by the content input instruction to the terminal device 2 determined as described above via the network 6.

  On the other hand, when it is determined in step S401 that there is no content input instruction (step S401: NO), the control unit 430 determines whether or not a content data transmission request has been received from the content distribution apparatus 1. The content data transmission request is made by specifying the content data by the content name or the like.

  In this process, when it is determined that there is a content data transmission request from the content distribution device 1 (step S410: YES), the control unit 430 extracts the content data corresponding to the content data transmission request from the hard disk device 403, It transmits to the content distribution apparatus 1 via the network 6 (step S411).

  If it is determined in step S410 that there is no content data transmission request from the content distribution device 1 (step S410: NO), the control unit 430 determines whether or not there is a transmission request for the identification information list from the terminal device 2. Determination is made (step S420).

  In this process, if it is determined that there is a request for transmission of the identification information list from the terminal device 2 (step S420: YES), the control unit 430 extracts the identification information list stored in the hard disk device 403. The control unit 430 transmits this identification information list to the terminal device that has made a transmission request for the identification information list via the network 6 (step S421).

  When the processing of steps S404, S411, and S421 is completed, or when it is determined in step S420 that there is no topology participation report from the terminal device 2 (step S420: NO), the control unit 430 terminates the service of the content input device 4 It is determined whether or not an operation has been performed (step S430). If it is determined that the service termination operation has not been performed (S430: NO), the processing from step S401 is repeated, and if it is determined that the service termination operation of the content input device 4 has been performed (S430: YES), the processing is terminated. To do.

  As described above, the content input device 4 is configured to transmit and input content data to the content distribution device 1 in the first distribution form and the terminal device 2 in the second distribution form. Thus, it is possible to manage the content data to be input to the first distribution form and the second distribution form in the content distribution system S. In addition, the identification information list is generated and updated, and transmitted in response to a request from the terminal device 2, whereby the terminal device 2 transmits the content data distributed in the first distribution form to the second distribution form. It is easy to get in.

  Further, since the content input device 4 can store an identification information list including identification information of content data other than the content data that is streamed by the content distribution device 1, content other than the content data that is directly distributed in the broadcast form Data can be acquired in a P2P grid distribution form. For example, when the content data is music content, it is possible to acquire music content viewed in the past in a P2P grid type distribution form.

(Description of the processing flow of the contact introduction device 5)
Next, a more specific operation of the contact destination introduction device 5 will be described with reference to FIG. FIG. 35 is a flowchart showing the entire processing in the contact introduction device 5. The following processes are executed by the control unit 530 of the contact introduction device 5 functioning as the above-described means.

  When the power of the contact introduction device 5 is turned on, the CPU 502 of the contact introduction device 5 executes initial setting operations such as initialization of access permission and work area reservation of the main storage device 505 and the hard disk device 503, and each program 517 to 519 are set to the execution state by the CPU 502 and the function as the control unit 530 is operated (step S500), and then the process proceeds to step S501.

  In step S501, the control unit 430 determines whether or not there is a contact introduction request (step S501). Here, whether or not there is a contact destination introduction request is determined based on whether or not the control unit 530 has received a contact destination introduction request transmitted from the terminal device via the network 6.

  In this process, when it is determined that there is a contact destination introduction request (step S501: YES), the control unit 530 returns a contact destination candidate in the second distribution form to the terminal device that has made the contact destination introduction request. (Step S502).

  When the process of step S502 is completed or when it is determined in step S501 that there is no contact destination introduction request (step S501: NO), the control unit 530 determines whether or not the service termination operation of the contact destination introduction device 5 has been performed. Is determined (step S503). If it is determined that the service end operation has not been performed (S503: NO), the processing from step S501 is repeated, and if it is determined that the service end operation of the contact destination introduction device 5 has been performed (S503: YES), the processing is performed. finish.

[8. Modification 1]
In the embodiment described above, the identification information list is transmitted from the content input device 4 to the terminal device 2. However, in the first modification, the content distribution device is added by adding the following configuration to the embodiment. Send from 1. The content input device 4 does not generate and update the identification information list, and the terminal device 2 does not request the content input device 4 to transmit the identification list.

  The control unit 130 of the content distribution device 1 transmits the identification information of the content data using the first distribution form. The content data identification information may be transmitted by being included in the content data, or may be transmitted separately from the content data. This process functions as an identification information transmission unit when the CPU 102 reads out and executes the content management program 121 from the main storage device 105. In other words, the identification information transmission means transmits the identification information of the content data to be streamed by the distribution means.

  Further, the terminal device 2 acquires the identification information of the content data requested to be downloaded using the identification information of the content data transmitted from the content distribution device 1. This process functions as an identification information receiving unit when the CPU 202 reads out and executes the content purchase program 221 from the main storage device 205. In other words, the identification information receiving unit receives the identification information of the content data transmitted from the content distribution device 1. Then, the identification information acquisition unit acquires the identification information of the content data requested to be downloaded from the identification information of the content data received by the identification information receiving unit.

  In this way, content data identification information necessary for downloading content data in the P2P grid distribution mode is transmitted from the content distribution device 1 to the terminal device 2. Accordingly, since the terminal device 2 does not need to request and acquire the identification information of the content data to be downloaded from the content input device 4 or the like, the processing in the content input device can be reduced. The content data identification information may be included in the header of the content packet to be streamed and transmitted from the content distribution device.

[9. Modification 2]
In the above embodiment, the root terminal device transmits the location information of the content data to the request terminal device, and the request terminal device downloads and acquires the content data from the content holding terminal device. The root terminal device may request the content holding terminal device to transmit content data to the requesting terminal device.

  In this case, as shown in FIG. 36, the root terminal device 2Z takes out the location information of the content holding terminal device 2Y that holds the content data requested from the requesting terminal device 2X from the index table 222. Then, based on the location information of the content holding terminal device 2Y, a content data transmission request including the location information of the request terminal device 2X is transmitted to the content holding terminal device 2Y. When the content holding terminal device 2Y receives the content data transmission request, the content holding terminal device 2Y transmits content data corresponding to the content data transmission request to the location information of the request terminal device 2X included in the content data transmission request. become.

  That is, when receiving the content search message from the request terminal device 2X as the root terminal device 2Z, the control unit 230 of the terminal device 2 uses the content holding terminal device information selection unit instead of the function of the content holding terminal device information return unit. It functions as a content data transmission request means for transmitting a request for transmitting content data including the location information of the request terminal device 2X with the location information of the selected content holding terminal device 2Y as a destination.

  The request terminal device 2X transmits a search message by the download destination search means, and the download data reception means receives content data corresponding to the search message from the content holding terminal device 2Y.

  As described above, the second distribution form can be configured such that the root terminal device requests the content holding terminal device to transmit the content data to the request terminal device.

[10. Other variations]
In the above embodiment, when each terminal device 2 participates in the content distribution system S, the terminal device 2 participates in the second distribution mode at the same time as the first distribution mode, but is downloaded from the user of the terminal device 2. You may make it participate in a 2nd delivery form, when there exists a request | requirement. When participating in the second distribution form at the same time as participating in the first distribution form, the number of terminal devices 2 participating in the second distribution form can be increased, and content distribution in the second distribution form can be stabilized. However, if the user of the terminal device 2 receives a download request and participates in the second distribution mode, the load on the terminal device 2 or the second distribution mode can be reduced. it can.

  Moreover, although the tree-like hierarchical structure has been described as an example of the broadcast form of the first distribution form, it is not limited to this, and a server-client type broadcast form may be used.

  In addition, the past delivery type content delivery system has been described as an example of the second delivery form. However, the present invention is not limited to this, and the present invention is not limited to this. The present invention is also applicable.

It is a figure showing an example of outline composition of a contents distribution system concerning this embodiment. It is a figure which shows the outline | summary operation example of the content delivery system which concerns on this embodiment. It is a figure which shows the outline | summary operation example of the content delivery system which concerns on this embodiment. It is a figure which shows the outline | summary operation example of the content delivery system which concerns on this embodiment. It is delivery operation explanatory drawing of the 1st delivery form of the content delivery system which concerns on this embodiment. It is the figure which represented notionally the function of the ring buffer area | region in the terminal device of FIG. It is delivery operation explanatory drawing of the 2nd delivery form of the content delivery system which concerns on this embodiment. It is a figure which shows an example of a mode that a routing table is produced by DHT. It is a figure which shows an example of the routing table in the terminal device of FIG. It is a figure which shows an example of a mode that a terminal device participates in a 2nd delivery form. It is a figure which shows an example of a mode that the terminal device 2 holding the content data is searched by DHT routing. It is a figure which shows an example of a mode that content data are hold | maintained at a terminal device by DHT routing. It is a figure which shows an example in which a registration message is transmitted to a root terminal device by DHT routing. It is a figure which shows an example of the index table in the terminal device of FIG. It is a figure which shows an example of the display screen of the terminal device in a 1st delivery form. It is a figure which shows an example of the display screen of the terminal device in a 2nd delivery form. It is a figure which shows the example of schematic structure of the content delivery apparatus of FIG. It is a figure which shows the schematic structural example of the terminal device of FIG. It is a figure which shows the example of schematic structure of the connection destination management apparatus of FIG. It is a figure which shows the example of schematic structure of the content input apparatus of FIG. It is a figure which shows the schematic structural example of the contact destination introduction apparatus of FIG. It is a flowchart which shows the whole process in the content delivery apparatus of FIG. It is a flowchart which shows the whole process in the terminal device of FIG. It is a flowchart which shows the whole process in the terminal device of FIG. It is a flowchart which shows the whole process in the terminal device of FIG. It is a flowchart which shows the initial stage channel setting process in the terminal device of FIG. It is a flowchart which shows the channel change process in the terminal device of FIG. It is a flowchart which shows the channel change process in the terminal device of FIG. It is a flowchart which shows the input content reception process in the terminal device of FIG. It is a flowchart which shows the content purchase process in the terminal device of FIG. It is a flowchart which shows the participation process to the 2nd delivery form in the terminal device of FIG. It is a flowchart which shows the content search process in the terminal device of FIG. It is a flowchart which shows the whole process in the connection management apparatus of FIG. It is a flowchart which shows the whole process in the content input apparatus of FIG. It is a flowchart which shows the whole process in the contact destination introduction apparatus of FIG. It is a figure which shows the example of an outline | summary operation | movement of the content delivery system in the modification 2.

Explanation of symbols

S content distribution system 1 content distribution device 2 terminal device 3 connection management device 4 content input device 5 contact destination introduction device 6 network 130, 230, 330, 430, 530 control unit

Claims (16)

The content distribution device is managed by a connection management device so that a plurality of terminal devices are logically connected in multiple layers in a hierarchical structure for each channel on the network, with the content distribution device streaming the content data through a plurality of channels, respectively. A first distribution form in which the content data transmitted from a device is sequentially stream-distributed from the upstream terminal device of the hierarchical structure to the downstream terminal device for each channel by the relay function of the terminal device; and the plurality of terminal devices A content delivery system having a second delivery form in which another terminal device that holds the content data delivers the content data based on a content data download request from one terminal device,
The content distribution device includes:
A delivery means for streaming delivery of the content data via the network;
The connection management device includes:
Connection state information storage means for storing connection state information of the terminal device constituting the hierarchical structure for each channel;
A connection destination candidate selection unit that selects a connection destination candidate from the connection state information stored in the connection state information storage unit when a connection destination introduction request is received from the terminal device via the network; and the connection destination candidate selection Notification means for notifying the connection destination candidate selected by the means to the terminal device that has transmitted the connection destination introduction request via the network;
The terminal device
Channel selection means for selecting the channel;
The connection destination introduction request for the channel selected by the channel selection means and the connection destination introduction request for a channel having a predetermined relationship with the channel are transmitted to the connection management device, and then the connection management device transmits the channel. A connection means for connecting to each of the connection destination candidates notified every time and participating in the first distribution form through a plurality of channels;
Streaming receiving means for streaming receiving the content data for each channel from the connection destination candidates connected via the network;
A ring buffer area for temporarily storing the content data received by the streaming receiving means for each channel;
Streaming reproduction means for streaming reproduction of the content data of the channel selected by the channel selection means among the content data stored in the ring buffer area;
When receiving a relay request for the content data from another terminal device, streaming relay means for streaming transfer the received content data to the terminal device that has made the relay request;
Download operation detection means for detecting an operation of a download request for content data according to the second distribution form;
When the download request operation is detected by the download operation detection means, the connection destination candidates relating to channels having a predetermined relationship with the channel selected by the channel selection means among the channels connected by the connection means Cutting means for cutting off the connection with
Identification information acquisition means for acquiring identification information of the content data in order to acquire the content data requested to be downloaded in the second distribution form when the download operation detection means detects the download request operation;
Download processing means for downloading the content data requested to be downloaded from the terminal device of the second distribution form based on the identification information of the content data acquired by the identification information acquisition means;
Content data storage means for storing the content data downloaded by the download processing means;
When the download of the content data requested for download by the download processing unit is completed, the connection destination introduction request for the channel disconnected by the disconnection unit is transmitted to the connection management device, and then notified from the connection management device. Reconnection means for reconnecting to the connection destination candidate;
A content distribution system comprising: The terminal device
Determining means for determining whether or not the entire content data requested to be downloaded is stored in the ring buffer area;
If it is determined by the determination means that the entire content data requested to be downloaded is stored in the ring buffer area, the content data is not downloaded according to the second distribution form, but is stored in the ring buffer area. Content data storage control means for storing the content data stored in the content data storage means,
If the determining means determines that the entire content data requested for download is stored in the ring buffer area, the disconnecting means does not disconnect the connection destination candidate of the channel in the connected state. The content distribution system according to claim 1. The terminal device
Determination means for determining whether or not the content data requested to be downloaded is stored in the content data storage means;
If the determination unit determines that the content data requested for download is stored in the content data storage unit, the disconnection unit does not disconnect the connection destination candidate of the channel in the connected state. The content distribution system according to claim 1, wherein the download processing unit does not download the content data according to the second distribution form. Content input means for transmitting content data distributed in the second distribution mode to some of the plurality of terminal devices;
Identification information list storage means for storing an identification information list including a plurality of identification information of content data to be streamed by the content distribution device;
An identification information list transmission means for transmitting the identification information list stored in the identification information list storage means to the plurality of terminal devices, and a content input device comprising:
The terminal device
An identification information list receiving means for receiving an identification information list transmitted from the content input device;
The identification information acquisition means includes
The content distribution system according to any one of claims 1 to 3, wherein identification information of the content data requested to be downloaded is acquired from the identification information list received by the identification information list receiving unit. 5. The content distribution system according to claim 4, wherein the identification information list storage unit stores an identification information list including identification information of content data other than content data to be streamed by the content distribution device. The content distribution device includes:
Identification information transmitting means for transmitting identification information of content data to be streamed by the distribution means;
The terminal device
Having identification information receiving means for receiving identification information of the content data transmitted from the content distribution device;
The identification information acquisition means includes
The content distribution system according to any one of claims 1 to 3, wherein the identification information of the content data requested to be downloaded is acquired from the identification information of the content data received by the identification information receiving means. . The content distribution device is managed by a connection management device so that a plurality of terminal devices are logically connected in multiple layers in a hierarchical structure for each channel on the network, with the content distribution device streaming the content data through a plurality of channels, respectively. A first distribution form in which the content data transmitted from a device is sequentially stream-distributed from the upstream terminal device of the hierarchical structure to the downstream terminal device for each channel by the relay function of the terminal device; and the plurality of terminal devices The terminal device in the content distribution system has a second distribution form in which another terminal device that holds the content data distributes the content data based on a content data download request from one terminal device. And
Channel selection means for selecting the channel;
The connection destination introduction request for the channel selected by the channel selection means and the connection destination introduction request for a channel having a predetermined relationship with the channel are transmitted to the connection management device, and then the connection management device transmits the channel. A connection means for connecting to each of the connection destination candidates notified every time and participating in the first distribution form through a plurality of channels;
Streaming receiving means for streaming receiving the content data for each channel from the connection destination candidates connected via the network;
A ring buffer area for temporarily storing the content data received by the streaming receiving means for each channel;
Streaming reproduction means for streaming reproduction of the content data of the channel selected by the channel selection means among the content data stored in the ring buffer area;
When receiving a relay request for the content data from another terminal device, streaming relay means for streaming transfer the received content data to the terminal device that has made the relay request;
Download operation detection means for detecting an operation of a download request for content data according to the second distribution form;
When the download request operation is detected by the download operation detection means, the connection destination candidates relating to channels having a predetermined relationship with the channel selected by the channel selection means among the channels connected by the connection means Cutting means for cutting off the connection with
Identification information acquisition means for acquiring identification information of the content data in order to acquire the content data requested to be downloaded in the second distribution form when the download operation detection means detects the download request operation;
Download processing means for downloading the content data requested to be downloaded from the terminal device of the second distribution form based on the identification information of the content data acquired by the identification information acquisition means;
Content data storage means for storing the content data downloaded by the download processing means;
When the download of the content data requested for download by the download processing unit is completed, the connection destination introduction request for the channel disconnected by the disconnection unit is transmitted to the connection management device, and then notified from the connection management device. Reconnection means for reconnecting to the connection destination candidate;
A terminal device comprising: Determining means for determining whether or not the entire content data requested to be downloaded is stored in the ring buffer area;
If it is determined by the determination means that the entire content data requested to be downloaded is stored in the ring buffer area, the content data is not downloaded according to the second distribution form, but is stored in the ring buffer area. Content data storage control means for storing the content data stored in the content data storage means,
If the determining means determines that the entire content data requested for download is stored in the ring buffer area, the disconnecting means does not disconnect the connection destination candidate of the channel in the connected state. The terminal device according to claim 7. Determination means for determining whether or not the content data requested to be downloaded is stored in the content data storage means;
If the determination unit determines that the content data requested for download is stored in the content data storage unit, the disconnection unit does not disconnect the connection destination candidate of the channel in the connected state. The terminal device according to claim 7 or 8, wherein the download processing unit does not download the content data according to the second distribution form. The plurality of identification information lists including a plurality of pieces of identification information of content data to be streamed and distributed by the content distribution device by transmitting content data to be distributed by the content distribution device to a part of the plurality of terminal devices. An identification information list receiving means for receiving the identification information list from the content input device to be transmitted to the terminal device,
The identification information acquisition means includes
10. The terminal device according to claim 7, wherein the identification information of the content data requested to be downloaded is acquired from the identification information list received by the identification information list receiving unit. The terminal device according to claim 10, wherein the identification information list includes identification information of content data other than content data that is stream-distributed by the content distribution device. Having identification information receiving means for receiving identification information of the content data transmitted from the content distribution device;
The identification information acquisition means includes
The terminal device according to any one of claims 7 to 9, wherein the identification information of the content data requested to be downloaded is acquired from the identification information of the content data received by the identification information receiving means. The cutting means is
A channel that has a predetermined relationship with a channel selected by the channel selection means, and that is in a connected state by the connection means when the download request operation is detected by the download operation detection means The connection with the said connection destination candidate regarding all the channels which have a predetermined relationship with the channel selected by the said channel selection means among these is cut | disconnected. The any one of Claims 7-12 characterized by the above-mentioned. Terminal device. The terminal device according to any one of claims 7 to 12, wherein the channel having the predetermined relationship is a channel having a channel number adjacent to the channel number selected by the channel selection unit.   The program for functioning a computer as each means in the terminal device of any one of Claims 7-14. The content distribution device is managed by a connection management device so that a plurality of terminal devices are logically connected in multiple layers in a hierarchical structure for each channel on the network, with the content distribution device streaming the content data through a plurality of channels, respectively. A first distribution form in which the content data transmitted from a device is sequentially stream-distributed from the upstream terminal device of the hierarchical structure to the downstream terminal device for each channel by the relay function of the terminal device; and the plurality of terminal devices A content distribution method in a content distribution system having a second distribution form in which another terminal device that holds the content data distributes the content data based on a content data download request from one terminal device. And
The delivery device streaming delivering the content data;
The connection management device storing connection state information of the terminal devices constituting the hierarchical structure in a connection state information storage unit;
The terminal device connects the connection destination introduction request for the channel selected by the channel selection means for selecting the channel and the connection destination introduction request for the channel having a predetermined relationship with the channel via the network. Sending to the management device;
When the connection management device receives the connection destination introduction request from the terminal device via the network, selecting a connection destination candidate from the connection state information stored in the connection state information storage unit;
The connection management device notifying the selected connection destination candidate to the terminal device that has transmitted the connection destination introduction request via the network;
The terminal device is connected to the connection destination candidates for each channel notified from the connection management device, and participates in the first distribution form through a plurality of channels;
The terminal device streaming receiving the content data from the connection destination candidates connected via the network for each channel;
The terminal device temporarily storing the streaming-received content data in a ring buffer area for each channel;
The terminal device performs streaming reproduction of the content data of the channel selected by the channel selection means among the content data stored in the ring buffer area;
When the terminal device receives a relay request for the content data from another terminal device, streaming the received content data to the terminal device that has made the relay request;
When the terminal device detects an operation of downloading content data according to the second distribution form, the connection destination candidate for the channel having a predetermined relationship with the selected channel among the channels in the connection state Disconnecting the connection;
A step of acquiring identification information of the content data in order to acquire the content data requested to be downloaded in the second distribution form when the terminal device has an operation of requesting download of the content data in the second distribution form; When,
The terminal device downloads the content data requested to be downloaded from the terminal device of the second distribution form based on the identification information of the acquired content data;
The terminal device storing the downloaded content data in content data storage means;
When the terminal device completes the download of the content data requested to be downloaded, the terminal device transmits the connection destination introduction request regarding the disconnected channel to the connection management device, and then the connection destination notified from the connection management device. Reconnecting to the candidate,
A content distribution method comprising:

Images