Video distribution system, receiver, and reception router

The present invention relates to a video distribution system, a receiving device, and a receiving router, and more particularly to a video distribution system, a receiving device, and a receiving router using an IP network.

A video distribution system to which a conventional IP network is applied consists of a distribution device and a receiving device connected to the IP network. When unicast transfer is used in the IP network, the receiving device makes a distribution request to the distribution device. The distribution device that transmits and receives the distribution request encodes the video data and transmits it to the receiving device, and the receiving device that receives the data decodes it, reconstructs it into a video, and displays it.

Alternatively, when multicast forwarding is used in an IP network, the distribution device encodes the video data and distributes it by multicast to the IP network, and the receiving device is, for example, IGMP (Internet Group Management Protocol) or MLD (Multicast Listener Discovery). Using a multicast routing protocol such as, a distribution request is made to an IP network, the received data is decoded, reconstructed into a video, and displayed (see, for example, Non-Patent Document 1).<nplcit num="1"><text>Hiroyuki Ouchi, Hiroaki Sato, Ken Takahashi, Hiromitsu Nagata "A Study on Program Switching in IP Multicast" Proceedings of the 2003 IEICE Society Conference, B-6-24</text></nplcit>

<p> However, in a conventional video distribution system using an IP network, it is not possible to distribute all channels to a receiving device, and there is a problem that it is difficult to realize broadcasting in which all channels are distributed to a receiving device similar to a television. is there. This is because, for example, in order to distribute 6 Mbps video equivalent to TV image quality from 20 channels equivalent to cable TV or satellite broadcasting to 100 channels or more, a line of at least 120 Mbps to 600 Mbps or more is required for each receiving device. The IP network access line has insufficient bandwidth even if it is a 100 Mbps access line, which is a high-speed line using optical fiber.</p><p> Further, in the video distribution system using the conventional IP network, there is a problem that it takes time to switch channels because all channels are not distributed to the receiving device.</p><p> For example, when unicast transfer is used, a control signal is transmitted and received between the receiving device and the distribution device, a request for stopping the distribution of data before switching is performed, and a request for distribution of data after switching is executed. Propagation delay and control processing delay in the distribution device occur. Alternatively, in the case of IP multicast as well, since the control message of the multicast protocol is transferred between the receiving device and the router accommodating the receiving device, the propagation delay of the control message and the processing delay in the router occur.</p><p> Due to the above delay, when switching channels in a video distribution system using an IP network, it takes time from the viewer executing the switching request in the receiving device until the video of the switched channel is displayed.</p><p> Further, as described above, since it takes time to switch channels, the viewer may mistakenly recognize that the channel switching has failed. Therefore, the viewer repeatedly retries the channel switching request, which may cause congestion in the IP network or the distribution device.</p><p> The present invention has been made in view of the above points, and an object of the present invention is to provide a video distribution system, a receiving device, and a receiving router that enable television broadcasting by all-channel transfer by multicast in an IP network.</p>

<p> FIG. 1 is a structural diagram of the principle of the present invention.</p><p> The present invention (claim 1) is a video distribution system including a distribution device 400 and a reception device 100 connected to an IP network 200, and the distribution device 400 hierarchically encodes video data into an IP network. The receiving device 100 has a means for transferring, and the receiving device 100 has one or more hierarchical identifiers from the lowest layer of data that are hierarchically encoded as a constant receiving layer for each channel identifier in advance, and the constant reception as an additional layer at the time of viewing. Video control that decodes the acquired data and configures and displays the video for the hierarchy management table 130, which is a storage means for storing and storing hierarchical identifiers higher than the hierarchy, and the display means 500 for viewing by the user. It has means 120, an IP network 200, a video control means 120, and an IP control means 110 connected to a hierarchical management table 130, and the video control means 120 has a channel to be displayed to the IP control means 110. A means for transmitting a channel request, a channel switching request, and a channel stop request message requesting data, and a means for receiving data from the IP control means 110, decoding the received data to form an image, and displaying the image on the display means. Have the means to The IP control means 110 is stored in the hierarchical management table based on the means for receiving the channel request, channel switching request, and channel stop request messages from the video control means 120 and the request from the video control means 120. , The distribution request of the constant reception layer of all channels and the additional layer at the time of viewing of the channel requested by the video control means is transmitted to the IP network 200, and the data corresponding to the distribution request is transmitted from the IP network 200. It has means for receiving and transferring to the video control means 120.</p><p> Further, the present invention (claim 2) is the video distribution system according to claim 1, and when the IP control means 110 receives a channel switching request from the video control means 120, the IP control means 110 refers to the hierarchical management table 130. The acquired distribution stop request including the layer identifier of the additional layer at the time of viewing of the channel before switching and the distribution request including the layer identifier of the additional layer at the time of viewing of the channel after switching acquired by referring to the layer management table 130. It has a means for transmitting to the IP network and a means for transferring the data of the constant reception layer of the channel after switching corresponding to the distribution request from the IP network 200 and the data of the additional layer at the time of viewing to the video control means 120. When the control means 120 receives only the data of the constant reception layer from the IP control means 110, the control means 120 decodes only the data of the constant reception layer to form and display the image, or the constant reception layer. When both the data of the above and the data of the additional layer at the time of viewing are received, the data of the constant reception layer and the data of the additional layer at the time of viewing of the channel after switching are decoded, and the video is configured and displayed. Including means.</p><p> The present invention (claim 3) is a video distribution system including a distribution device connected to an IP network, a receiving router, and at least one receiving device. The distribution device hierarchically encodes video data. The receiving device has a means for transferring data to the IP network, the receiving device has a video controlling means for decoding the acquired data to the display means for viewing by the user, and the receiving router has a means for composing and displaying the video. One or more layer identifiers from the lowest layer of data that are connected to the IP network and receiving device and are layer-encoded as a constant reception layer for each channel identifier in advance, and an additional layer for viewing, which is higher than the constant reception layer. It has a hierarchical management table which is a storage means for registering and storing the hierarchical identifier of the above, an IP network, a video control means of the receiving device, and an IP control means connected to the hierarchical management table, and video control of the receiving device. The means is to send a channel request, a channel switching request, and a channel stop request message requesting data of the channel to be displayed to the IP control means of the receiving router. The IP control means of the receiving router includes means for receiving data from the IP control means, decoding the received data to form an image, and displaying the image on the display means. Means for receiving messages of channel request, channel switching request, and channel stop request, constant reception hierarchy of all channels stored in the hierarchy management table based on the request from the video control means, and the video control. It has an additional layer at the time of viewing of the channel requested by the means, and a means for transmitting the distribution request to the IP network, receiving the data corresponding to the distribution request from the IP network, and transferring the data to the video control means. ..</p><p> Further, the present invention (claim 4) is the video distribution system according to claim 3, wherein the IP control means of the receiving router receives a channel switching request from the video control means of the receiving device, the hierarchical management table. Distribution stop request including the hierarchical identifier of the additional layer at the time of viewing of the channel before switching obtained by referring to the above, and distribution including the hierarchical identifier of the additional layer at the time of viewing of the channel after switching acquired by referring to the hierarchy management table. It has a means for transmitting the request to the IP network and a means for transferring the data of the constant reception layer of the switched channel corresponding to the distribution request from the IP network and the data of the additional layer at the time of viewing to the video control means. When the video control means of the receiving device receives only the data of the constant reception layer from the IP control means of the receiving router, it decodes only the data of the constant reception layer, configures and displays the video, or displays it. When both the data of the constant reception layer and the data of the additional layer at the time of viewing are received, the data of the continuous reception layer and the data of the additional layer at the time of viewing of the channel after switching are decoded to obtain the video. Includes means to configure and display.</p><p> The present invention (claim 5) is a receiving device connected to a distribution device connected to an IP network, from the lowest layer of data that is hierarchically encoded as a constant receiving layer for each channel identifier in advance. Data acquired for the above-mentioned hierarchical identifier and the hierarchical management table which is a storage means for storing and storing the hierarchical identifier higher than the always-received hierarchy as an additional layer for viewing, and the display means for viewing by the user. It has a video control means for decoding and displaying a video, and an IP network, a video control means, and an IP control means connected to a hierarchical management table, and the video control means refers to the IP control means. Then, a means for transmitting a channel request, a channel switching request, and a channel stop request message requesting the data of the channel to be displayed, and a means for receiving the data from the IP control means, and decoding the received data to form a video. The IP control means has a means for displaying the data on the display means, and the IP control means has a means for receiving a channel request, a channel switching request, and a channel stop request message from the video control means. Based on the request from the video control means, the IP network delivers the distribution request of the constant reception layer of all channels stored in the hierarchy management table and the additional layer at the time of viewing of the channel requested by the video control means. It has a means for transmitting data to the IP network, receiving data corresponding to the distribution request from the IP network, and transferring the data to the video control means.</p><p> Further, the present invention (claim 6) is the receiving device according to claim 5, wherein when the IP control means receives the channel switching request from the video control means, it is acquired by referring to the hierarchical management table. A distribution stop request including the layer identifier of the additional layer at the time of viewing of the channel before switching and a distribution request including the layer identifier of the additional layer at the time of viewing of the channel after switching acquired by referring to the hierarchy management table are transmitted to the IP network. The video control means has a means for transferring the data of the constant reception layer of the channel after switching corresponding to the distribution request from the IP network and the data of the additional layer at the time of viewing to the video control means, and the video control means is IP control. When only the data of the always-received layer is received from the means, only the data of the always-received layer is decoded to compose and display the video, or the data of the always-received layer and the additional layer at the time of viewing are displayed. When the data is received together, the means for decoding the data of the constant reception layer and the data of the additional layer at the time of viewing of the channel after switching to compose and display the video is included.</p><p> The present invention (claim 7) is a distribution device connected to an IP network and a reception router connected to at least one reception device, and is layer-encoded in advance for each channel identifier as a constant reception layer. One or more hierarchical identifiers from the lowest layer of data, and a hierarchical management table that is a storage means for registering and storing hierarchical identifiers higher than the constant reception layer as additional layers for viewing, IP network, and video of the receiving device. It has a control means and an IP control means connected to a hierarchical management table, and the IP control means is a means for receiving a channel request, a channel switching request, and a channel stop request message from the video control means of the receiving device. And, based on the request from the video control means, the distribution request of the constant reception layer of all channels stored in the hierarchy management table and the additional layer at the time of viewing of the channel requested by the video control means. It has means for transmitting to an IP network, receiving data corresponding to the distribution request from the IP network, and transferring the data to the video control means.</p><p> Further, the present invention (claim 8) is the receiving router according to claim 7, and when the IP control means receives a channel switching request from the video control means of the receiving device, the IP control means refers to the hierarchical management table. IPs the acquired distribution stop request including the layer identifier of the additional layer at the time of viewing of the channel before switching and the distribution request including the layer identifier of the additional layer at the time of viewing of the channel after switching acquired by referring to the hierarchy management table. It has a means for transmitting to the network and a means for transferring the data of the constant reception layer of the switched channel corresponding to the distribution request from the IP network and the data of the additional layer at the time of viewing to the video control means.</p><p> The present invention (claim 9) is for a distribution device connected to an IP network and a reception device connected to the reception router in a video distribution system having a reception router, and for a display means to be viewed by a user. It has a video control means that decodes the data acquired from the receiving router, configures the video, and displays it on the display means, and the video control means is a channel that displays the data to the IP control means in the receiving router. A means for transmitting a message of a channel request, a channel switching request, and a channel stop request for requesting data, and a means for receiving data from an IP control means, decoding the received data to form an image, and displaying the image on a display means. Means and.</p><p> Further, the present invention (claim 10) is the receiving device according to claim 9, wherein the video control means always receives only the data of the reception layer from the IP control means of the receiving router. When only the data of the constant reception layer is decoded and the video is configured and displayed, or when both the data of the constant reception layer and the data of the additional layer at the time of viewing are received, the constant of the channel after switching. It includes means for decoding the data of the reception layer and the data of the additional layer at the time of viewing to compose and display the video.</p>

<p> As described above, according to the present invention, in an IP network, television broadcasting by all-channel transfer can be realized by multicast, and high-speed channel switching corresponding to user's channel surfing can be realized.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]

FIG. 2 shows a network configuration according to the first embodiment of the present invention.

The network shown in the figure has a configuration in which a plurality of receiving devices 100 are connected to the IP network 200 and the distribution device 400 is connected to the IP network 200.

FIG. 3 shows the configuration of the receiving device according to the first embodiment of the present invention.

The receiving device 100 shown in the figure has an IP control unit 110, a video control unit 120, and a hierarchical management table 130, and the video control unit 120 and the hierarchical management table 130 are connected to the IP control unit 110.

The IP control unit 110 is connected to the IP network 200 and transfers the data received from the IP network 200 to the video control unit 120 based on the data acquired from the hierarchical management table 130. In addition, messages such as channel request, channel switching, and channel stop are received from the video control unit 120.

The video control unit 120 transmits a message such as a channel request, channel switching, and channel stop to the IP control unit 110. Further, the video control unit 120 receives data from the IP control unit 110, decodes the received data, constitutes a video, and displays the video on a display device 500 such as a viewer's display.

The hierarchy management table 130 is composed of storage means such as a memory, and as shown in FIG. 4, is a table that stores a channel identifier, a hierarchy number, a hierarchy identifier, and a hierarchy attribute. The channel identifier is channel identification information common to the video control unit 120 and the IP control unit 110. For example, in the case of a television, a channel number such as 1 channel 2 channel can be considered. For the layer number, for example, "1" is used as the basic layer, and numbers are assigned in the order of layers such as "2" and "3". The hierarchical identifier is an identifier in the IP network corresponding to the hierarchical number, and a multicast address or a combination of a multicast address and a source address can be considered. The hierarchy attribute defines whether it is a constant reception hierarchy or an additional hierarchy during viewing. However, the example shown in FIG. 4 is a description for clarifying the description, and the present invention is not limited to the channel identification method, the number of channels, the number of layers, the layer identification method, and the number of layer identifiers.

Further, the constant reception layer and the additional layer at the time of viewing may each be composed of a plurality of layers.

Next, the operation of the network in the above configuration will be described.

FIG. 5 is a sequence chart of the operation of the system according to the first embodiment of the present invention. In the sequence chart shown below, "Ch" indicates a channel, "always" indicates that the hierarchical attribute is always a reception hierarchy, and "addition" indicates that the hierarchical attribute is an additional hierarchy during viewing. There is.

Step 101) For example, the data shown in FIG. 4 is registered in the hierarchical management table 130.

Step 102) The video control unit 120 and the IP control unit 110 of the receiving device 100 are activated.

Step 103) The IP control unit 110 acquires the hierarchical identifier of the always-received hierarchy of all channels from the hierarchical management table 130, and requests the IP network 200 for the acquired hierarchical identifier data. For example, the IP control unit 110 transmits a hierarchy identifier request requesting batch acquisition of the reception hierarchy to the hierarchy management table 130 shown in FIG.

Step 104) When the hierarchical management table 130 acquires the hierarchical identifier request from the IP control unit 110, the hierarchical management table 130 returns the requested hierarchical identifier to the IP control unit 110. For example, the data that the constant reception layer of "Channel 1" is only "Layer 1" and "230.0.0.1", and the constant reception layer of "Channel 2" is only "Layer 1" and is "230.0.10.1" is transmitted. To do.

Step 105) Next, the IP control unit 110 sends a multicast join request specifying "230.0.0.1" and "230.0.10.1" to the IP network 200. For example, in IGMPv3 and MLDv2, it is conceivable to send a "Report message" in which multicast addresses are specified in a batch. Alternatively, when the hierarchical identifier is a combination of a multicast address and a source address, it is conceivable to send a "Report message" in which the combination of the multicast address and the source address is collectively specified.

Step 106) The IP control unit 110 acquires data from the IP network 200. When the "Report message" in which the above multicast addresses are collectively specified is sent, the data of "230.0.0.1" and the data of "230.0.10.1" arrive independently from the IP network 200.

Step 107) The video control unit 120 transmits a channel request for the video to be displayed on the display device 500 first to the IP control unit 110 automatically or by an operation of the viewer. For example, assume that the channel request is "channel 1".

Step 108) Upon receiving the channel request from the video control unit 120, the IP control unit 110 transmits the layer identifier request, for example, the layer identifier request of channel 1 to the layer management table 130.

Step 109) The IP control unit 110 acquires the hierarchy identifier from the hierarchy management table 130. For example, the hierarchical identifier of "Channel 1" acquires data that the constant reception hierarchy is "Layer 1" and "230.0.0.1", and the additional hierarchy during viewing is "Layer 2" and "230.0.0.2". To do.

Step 110) Next, the IP control unit 110 transfers the data of 230.0.0.1 being received and the fact that the 230.0.0.1 is layer 1 of the channel 1 to the video control unit 120.

Step 111) When the video control unit 120 receives only the "layer 1" data from the IP control unit 110, the video control unit 120 decodes and configures the video from only the "layer 1" data, and configures the user's display device. Display at 500.

Step 112) Further, the IP control unit 110 sends a multicast join request for which the hierarchical identifier 230.0.0.2 is specified to the IP network 200.

Step 113) When the IP control unit 110 starts receiving the data of the layer identifier "230.0.0.2" from the IP network 200, the data of "230.0.0.2" and "Layer 2" in which "230.0.0.2" is "Channel 1" Is transferred to the video control unit 120.

Step 114) After the video control unit 120 starts receiving the data of the layer 2, the video control unit 120 decodes the video from the data of the layer 1 and the layer 2, configures it, and displays it on the display device 500.

As described above, in the present embodiment, the hierarchical coded data is used, and the video data is divided into a low bit rate constant reception layer and a viewing additional layer for improving video quality, and the video configuration is used as the constant reception layer. The minimum required layer of data is distributed to all channel receivers 100. As a result, all channels can be distributed to the receiving device 100. Further, by distributing the data of the additional layer at the time of viewing that improves the video quality only to the necessary channels, the video quality equivalent to that of the television can be obtained.

For example, even if the video data is 6 Mbps, if the continuous reception layer is 500 kbps and the additional layer during viewing is 5.5 Mbps, 100 channels are always distributed and even if one channel is viewed, the access line is 55.5 Mbps. All you need is a band. As a result, broadcasting similar to that of a television can be realized with a 100 Mbps access line.

[Second Embodiment]

In the present embodiment, processing when the IP control unit is requested by the video control unit to switch channels will be described.

The network configuration, the configuration of the receiving device, and the contents of the hierarchical management table are the same as those in the first embodiment described above.

FIG. 6 is a sequence chart of the operation of the system according to the second embodiment of the present invention.

Step 201) It is assumed that the video control unit 120 is playing "channel 1" as an initial state. At this time, the video control unit 120 receives the data of the constant reception layer of "channel 1" and the data of the additional layer during viewing.

Step 202) When the video control unit 120 performs channel switching from channel 1 to channel 2, it transmits a channel switching request to channel 2 to the IP control unit 110.

Step 203) When the IP control unit 110 receives the channel switching request from the video control unit 120, the IP control unit 110 changes the data transmitted to the video control unit 120 from channel 1 to channel 2. At this time, the IP control unit 110 receives the data of the constant reception layer of "channel 2", but does not receive the data of the additional layer at the time of viewing, so that only the data of the constant reception layer is transferred. become.

Step 204) In this case, the video control unit 120 reproduces the video of channel 2 only from the constant reception layer.

Step 205) The IP control unit 110 sends a multicast exit request including the layer identifier 230.0.0.2 to the IP network 200 in order to stop the data of the additional layer during viewing of channel 1.

Step 206) The IP control unit 110 requests the hierarchy identifier from the hierarchy management table 130 in order to acquire the data of the additional hierarchy at the time of viewing of channel 2.

Step 207) The IP control unit 110 acquires "230.0.10.2" as the hierarchy identifier of the additional hierarchy at the time of viewing of "channel 2" from the hierarchy management table 130.

Step 208) The IP control unit 110 sends a multicast participation request including "230.0.10.2" to the IP network 200.

In this case, in order to prevent congestion of the access line, after confirming the data stop of the additional layer during viewing of "Channel 1", the multicast participation request of the additional layer during viewing of "Channel 2" is transmitted. May be good.

Step 209) When the IP control unit 110 starts receiving the data of "230.0.10.2" from the IP network 200, the data of "230.0.10.2" and the data of "230.0.10.2" are "Channel 2" "Channel 2". Transferring the fact that it is "Layer 2" to the video control unit 120.

Step 210) From this point onward, the video control unit 120 decodes and configures the video from the data of the constant reception layer and the additional layer at the time of viewing of the channel 2, and displays the video on the display device 500.

As described above, in the present embodiment, in the channel switching, the minimum data necessary for the video configuration is distributed, and high-speed channel switching is possible in the receiving device 100. Immediately after switching channels, the data of the additional layer during viewing is not received, and there is a possibility that deterioration of video image quality may be recognized, but if the data of the additional layer during viewing is received, the video quality will improve. In addition, it is more effective than the conventional method in which the minimum data necessary for the video configuration cannot be received and the video cannot be displayed at all.

[Third Embodiment]

In this embodiment, an example in which a timer is used at the time of channel switching in the second embodiment described above will be described.

FIG. 7 shows the configuration of the receiving device according to the third embodiment of the present invention. The difference from the configuration of FIG. 3 is that the channel switching state monitoring timer 111 is provided in the IP control unit 110.

FIG. 8 is a sequence chart of the operation of the system according to the third embodiment of the present invention.

Step 301) This step is the same as the second embodiment described above.

Step 302) Similar to the second embodiment, when the video control unit 120 performs channel switching from channel 1 to channel 2, the IP control unit 110 makes a channel switching request to channel 2. Send to.

Step 303) At this time, the IP control unit 110 receives the data of the constant reception layer of "channel 2", but does not receive the data of the additional layer at the time of viewing, so that only the data of the constant reception layer is received. Forward.

Step 304) The video control unit 120 reproduces the video of channel 2 only from the reception layer at all times.

Step 305) The IP control unit 110 sends a multicast exit request including the layer identifier 230.0.0.2 to the IP network 200 in order to stop the data of the additional layer during viewing of channel 1.

Step 306) At this time, the IP control unit 110 stores in the memory (not shown) that the channel after switching is channel 2.

Step 307) Further, the IP control unit 110 activates the channel switching status monitoring timer 111. The value of the timer is a predetermined value, and the present invention does not limit the value of the timer. As the value of the timer, the IP control unit 110 learns the habit of the viewer's channel switching request, does not send unnecessary messages to the IP network, and automatically receives additional layers during viewing as soon as possible. It is also possible to change to. For example, a method is conceivable in which the IP control unit 110 measures the reception time interval of the channel switching request and changes it to the sum of the average value of the measurement samples equal to or less than the predetermined time and the margin time.

Step 308) When the channel switching status monitoring timer 111 times out, the IP control unit 110 requests the hierarchy identifier from the hierarchy management table 130 in order to acquire the data of the additional hierarchy at the time of viewing of channel 2.

Step 309) The IP control unit 110 acquires the additional hierarchical identifier 230.0.10.2 at the time of viewing of channel 2 from the hierarchical management table 130.

Step 310) The IP control unit 110 transmits a multicast join request including the hierarchical identifier 230.0.10.2 to the IP network 200.

Step 311) When the IP control unit 110 starts receiving the data of "230.0.10.2" from the IP network 200, the data of the hierarchical identifier "230.0.10.2" and the data of the "230.0.10.2" are the "channel 2". Transferring that it is "layer 2" to the video control unit 120.

Step 312) From this point onward, the video control unit 120 decodes the data of the constant reception layer and the additional layer during viewing of "channel 2", configures the video, and displays it on the display device 500.

As described above, according to the present embodiment, since a time interval is provided between the distribution stop processing of the channel before switching and the distribution start processing of the channel after switching by timer monitoring at the time of channel switching, the distribution device, Alternatively, it is possible to reduce the processing load of the router installed in the IP network.

[Fourth Embodiment]

In the present embodiment, when the IP control unit 110 receives a channel switching request from the video control unit 120 while the channel switching state monitoring timer is operating, the channel stored in the memory (not shown) is switched to the latest channel. An example of changing to the channel after switching specified in the request and restarting the channel switching status monitoring timer will be described.

The configuration of the system and the receiving device 100 in the present embodiment is the same as that in the third embodiment described above.

FIG. 9 is a sequence chart of the operation of the system according to the fourth embodiment of the present invention.

Step 401) The video control unit 120 is playing back the video of channel 1.

Step 402) When the video control unit 120 performs channel switching from channel 1 to channel 2, the video control unit 120 transmits a channel switching request to channel 2 to the IP control unit 110.

Step 403) The IP control unit 110 sends a multicast exit request to the IP network 200 in order to stop the data of the additional layer during viewing of channel 1.

Step 404) The IP control unit 110 changes the data to be transmitted to the video control unit 120 from channel 1 to channel 2.

Step 405) At this time, the IP control unit 110 stores in the memory (not shown) that the channel after switching is channel 2, as in the third embodiment described above.

Step 406) Further, the IP control unit 110 activates the channel switching status monitoring timer 111. The value of the timer is a predetermined value, and the present invention does not limit the value of the timer.

Step 407) The video control unit 120 decodes the data in the layer 1 of the channel 2, constructs the video, and reproduces it on the display.

Step 408) Here, it is assumed that the IP control unit 110 receives the channel switching request from the video control unit 120 before the time-out of the channel switching state monitoring timer 111.

Step 409) The IP control unit 110 changes the channel identifier after channel switching stored in the memory (not shown) from "channel 2" to "channel 3", and changes the data of "channel 3" to the video control unit. Send to 110.

Step 410) The IP control unit 110 restarts the channel switching status monitoring timer 111. After that, when the IP control unit 110 receives the channel switching request before the time-out of the channel switching state monitoring timer 111, the IP control unit 110 changes the channel identifier after the channel switching stored in the memory (not shown) each time.

Step 411) The IP control unit 110 restarts the channel switching status monitoring timer 111.

Step 412) The IP control unit 110 assumes that the channel switching status monitoring timer 111 has timed out.

Step 413) At this time, the IP control unit 110 requests the hierarchy identifier from the hierarchy management table 130 in order to acquire the data of the additional hierarchy at the time of viewing of channel 3.

Step 414) The IP control unit 110 acquires the additional hierarchical identifier 230.0.20.2 for viewing Channel 3 from the hierarchical management table 130.

Step 415) The IP control unit 110 transmits a multicast participation request including the hierarchical identifier 230.0.20.2 to the IP network 200, and acquires the data corresponding to the identifier.

Step 416) The IP control unit 110 transfers the acquired data of the hierarchical identifier 230.0.20.2 and the fact that the 230.0.20.2 is the layer 2 of the channel 3 to the video control unit 120.

Step 417) From this point onward, the video control unit 120 decodes the data of the constant reception layer and the additional layer at the time of viewing of the channel 3, configures the video, and displays it on the display device 500.

As described above, according to the present embodiment, when monitoring the timer at the time of channel switching, continuous channel switching is performed in consideration of an operation called channel surfing in which the viewer temporarily repeats channel switching. It is also possible to monitor and suppress the transmission of delivered messages when such continuous channel operations are performed. It is also effective in reducing the processing load of the distribution device or the router installed in the IP network.

[Fifth Embodiment]

In the present embodiment, a channel storage unit for storing channels is provided, and for all channels, the always-receive layer is stored instead of transmitting the delivery request for which the hierarchical identifier of the always-receive layer is specified to the IP network. An example of sending a delivery request specifying the hierarchical identifier of is described.

FIG. 10 shows the configuration of the receiving device according to the fifth embodiment of the present invention.

The receiving device 100 shown in the figure is a configuration in which a channel storage unit 140 is added to the configuration of FIG. 7 in the above-described third embodiment. The channel storage unit 140 is composed of a storage medium such as a memory or a hard disk.

FIG. 11 is a sequence chart (No. 1) of the system according to the fifth embodiment of the present invention.

Step 501) The video control unit 120 transmits a channel request and a channel switching request (channel 2) to the IP control unit 110.

Steps 502 to 506) When the IP control unit 110 receives the channel request and the channel switching request from the video control unit 120, if it is receiving the data of the constant reception layer of the channel, the above-mentioned second to fourth steps are taken. The same operation as that of the embodiment of is performed.

Step 507) The video control unit 120 transmits a channel request and a channel switching request (channel 3) to the IP control unit 110.

Steps 508 to 510) When the IP control unit 110 receives the channel request and the channel switching request from the video control unit 120, if the data of the constant reception layer of the channel after switching is not received, the channel storage unit 140 is in the channel. To register. For example, when a channel switching request from the video control unit 120 to "channel 3" is received, it is determined that the data in the constant reception layer of "channel 3" has not been received, and "channel 3" is sent to the channel storage unit 140. To register. The channel storage unit 140 responds to the IP control unit 110 that "channel 3" has been registered.

Steps 511 and 512) The IP control unit 110 requests the hierarchical identifier of "channel 3" from the hierarchical management table 130 and acquires the hierarchical identifier.

Step 513) The IP control unit 110 transmits a multicast exit request for the additional layer during viewing of channel 2 to the IP network 200 as the channel is switched from channel 2 to channel 3.

Step 514) Also, based on the hierarchy identifier (channel 3) obtained from the hierarchy management table 130, send a multicast join request to the IP network 200.

In the above example, an example in which the channel switching state monitoring timer 111 is not used is shown, but the processing when the channel switching state monitoring timer 111 is used is as follows.

FIG. 12 is a sequence chart (No. 2) of the system according to the fifth embodiment of the present invention.

When the channel switching status monitoring timer 111 is used, the IP control unit 110 sets the timeout of the channel switching status monitoring timer 111 when receiving the channel switching request, as in steps 408 to 412 in the fourth embodiment described above. It waits, determines whether or not the data in the constant reception layer of the switched channel (for example, "channel 3") has not been received, and if it has not been received, the channel storage unit 140 has not received the channel (for example, "channel 3"). Remember Channel 3) (steps 521 to 523).

According to the above embodiment, when the number of channels to be viewed is small, not all channels including the channels with low viewing frequency are delivered to the receiving device, but only the recently displayed channel is received. By delivering to the device, the bandwidth used by the access line can be saved. For example, when the constant reception layer is 500 kbps, if the constant distribution is limited to 10 channels, a band of 5 Mbps is sufficient as an access line, and the remaining band can be effectively used for other data transfer.

[Sixth Embodiment]

In the fifth embodiment described above, the channel is stored in the channel storage unit 140, but in the present embodiment, not only the channel but also the time when the channel is stored or the time when the expiration date is stored is stored and predetermined. An example of deleting the channel / time information when the time has passed will be described.

The configuration of the receiving device in the present embodiment is the same as that in the fifth embodiment described above.

FIG. 13 is a sequence chart of the operation of the receiving device according to the sixth embodiment of the present invention. The parts other than the following description are the same as those in the fifth embodiment.

When the IP control unit 110 registers "channel 3" in the channel storage unit 140, the IP control unit 110 registers "channel 3" and the current time in the channel storage unit 140 (step 604). The channel storage unit 140 deletes the channel 3 after a lapse of a predetermined time (step 611).

Further, when the IP control unit 110 registers "channel 3" in the channel storage unit 140, the IP control unit 110 also registers the expiration time, and the channel storage unit 140 registers "channel 3" when the finite expiration time arrives. You may delete the memory of.

It is effective from the viewpoint of improving the control speed to cache the recently displayed channel information by reflecting the channel requested by the viewer as in the present embodiment.

[7th Embodiment]

In the present embodiment, when a new channel is stored in the channel storage unit 140, when the maximum number of channels is exceeded, among the channels already stored in the storage unit 140, from the storage time to the current time. An example of deleting the memory of the channel having the longest time or the channel having the shortest time from the current time to the expiration date and registering a new channel will be described.

The configuration of the receiving device 100 in the present embodiment is the same as that in the fifth embodiment described above.

FIG. 14 is a sequence chart of the operation of the receiving device according to the seventh embodiment of the present invention.

When "Channel 1" and "Channel 2" are already registered in the channel storage unit 140 (step 701), the IP control unit 110 requests "Channel 3" when registering "Channel 3" in the channel storage unit 140. Is registered in the channel storage unit 140, and when the maximum number of channels is exceeded, the channel storage unit 140 stores the storage of the channel having the maximum time from the storage time to the current time (for example, channel 1). Delete and register "Channel 3" (step 705). At this time, the memory storage unit 140 notifies the IP control unit 110 that the storage of channel 1 has been deleted (step 706).

The IP control unit 110 notified of the memory deletion of "channel 1" transmits a multicast exit request to the IP network 200 for the constant reception layer of "channel 1" (step 709). In this case, the multicast exit request of "channel 1" can be integrated into the same message as the multicast exit request of "channel 3" due to the channel switching from "channel 2" to "channel 3".

Limiting the number of channels to be cached and deleting infrequently used data from the storage means as in the present embodiment is effective from the viewpoint of improving memory usage efficiency.

[Eighth embodiment]

In the present embodiment, when the IP control unit 110 receives the channel request from the video control unit 120 and when the channel switching request is received, the time when the channel of the channel storage unit 140 is stored is updated for the channel. An example of doing so will be described.

The configuration of the receiving device 100 in the present embodiment is the same as that in the fifth embodiment described above.

FIG. 15 is a sequence chart of the operation of the receiving device according to the eighth embodiment of the present invention.

When the IP control unit 110 receives the channel switching request from the video control unit 120 (step 801), the IP control unit 110 requests the memory storage unit 140 to register a new channel and time regardless of whether the reception layer is constantly receiving or not receiving. (Step 802). If the channel for which the registration request is made is stored, the channel storage unit 140 updates the registration time or expiration time of the channel (step 803), and the IP control unit 110 indicates that the channel has been registered (updated). Notify (step 804).

From the viewpoint of cache, as in the present embodiment, extending the retention period of data having a high read frequency is effective from the viewpoint of improving the control speed.

[9th embodiment]

In this embodiment, an example of stopping / starting the power supply when the above-mentioned channel storage unit 140 is configured by the non-volatile memory will be described.

The configuration in the present embodiment is the same as that in the fifth embodiment described above, but the channel storage unit 140 is a non-volatile memory.

FIG. 16 is a flowchart of the operation of the receiving device according to the ninth embodiment of the present invention.

Currently, the receiving device 100 is in a stopped state (step 901), and "channel 1" and "channel 2" are stored in the channel storage unit 140 (step 902). Further, it is assumed that the hierarchical identifiers of "channel 1", "channel 2", and "channel 3" are stored in the memory of the hierarchical management table 130 (step 903).

When the receiving device 100 is activated (step 904), the IP control unit 110 reads out the stored channel from the channel storage unit 140 (steps 905 and 906). For example, reading "channel 1" and "channel 2" Next, the IP control unit 110 reads the hierarchical identifiers of the always-received layers of "channel 1" and "channel 2" from the hierarchy management table 130 (steps 907,908). Send a multicast join request to the IP network 200 to the always-on tiers of "channel 1" and "channel 2" (step 909). As a result, the data of the constant reception layer of "channel 1" and "channel 2" is transmitted from the IP network 200 (step 910).

As in the present embodiment, storing the final display channel in the non-volatile memory when the power is stopped, requesting distribution to the previous final display channel when the power is restarted, and displaying the display is an operation of the viewer at the time of startup. It is effective in terms of simplifying and improving convenience.

[10th Embodiment]

Also in this embodiment, an example in which the power supply is stopped / started when the channel storage unit 140 is configured by the non-volatile memory in the above-mentioned ninth embodiment will be described.

In the present embodiment, the channels stored in the channel storage unit 140 are different from those in the ninth embodiment described above, and in the present embodiment, an example of storing the recently displayed channel and the last displayed channel will be described. ..

The contents of the receiving device 100 configuration and the hierarchical management table 130 in this embodiment are the same as those in the fifth embodiment described above, but the channel storage unit 140 is a non-volatile memory.

It is assumed that the video control unit 120 is playing back the video of channel 1 (step 1001). Channel 1 and channel 2 are stored in the channel storage unit 140 of the non-volatile memory (step 1002). It is assumed that the hierarchy management table 130 stores the hierarchy identifiers of "channel 1", "channel 2", and "channel 3" (step 1003).

When the IP control unit 110 acquires the last reproduced and displayed channel, for example, "channel 1" from the video control unit 120 during the stop processing, the receiving device 100 writes the "channel 1" to the channel storage unit 140 ( Step 1004,1005).

Next, at startup, the receiving device reads the channel and the last regenerated and displayed channel (channel 1) from the channel storage unit 140 in the IP control unit 110 (steps 1006, 1007). For example, when the channels stored in the channel storage unit 140 are "channel 1" and "channel 2" and the last reproduced and displayed channel is "channel 1", "channel 1" and "channel 2" are read out. ..

Next, the IP control unit 110 reads the layer identifiers of the "channel 1" constant reception layer and the viewing additional layer, and the "channel 2" constant reception layer hierarchy identifiers from the layer management table 130 (steps 1008, 1009). A multicast join request is sent to the IP network 200 for the always-receive layer of "channel 1", the additional layer for viewing, and the always-receive layer of "channel 2" (step 1010).

When the IP control unit 110 receives the data of the constant reception layer of "channel 1" and the additional layer during viewing from the IP network 200 (step 1011), the IP control unit 110 transfers the data to the video control unit 120 as the last displayed / reproduced channel (step 1012). ). Alternatively, if the IP control unit 110 explicitly requests a channel from the video control unit 120 within a predetermined time from the start, the IP control unit 110 does not explicitly display the channel, but the channel that is explicitly requested. Data may be transferred to the video control unit 120.

According to the above embodiment, the final display channel can be displayed to improve the convenience of the viewer, and only the recently displayed channel can be delivered to the receiving device 100 to reduce the bandwidth used by the access line.

[11th Embodiment]

In the present embodiment, all the data of the constant reception layer received from the IP network 200 by the IP control unit 110 is transmitted to the video control unit 120, and each channel acquired from the IP control unit 110 in the video control unit 120. An example of composing a video from the data of the constant reception layer of the above and displaying it in a list will be described.

The configuration of the receiving device in the present embodiment is the same as that in the first embodiment described above.

FIG. 18 is a sequence chart of the operation of the receiving device according to the eleventh embodiment of the present invention.

The IP control unit 110 transmits to the video control unit 120 data of the constant reception layer of all channels receiving from the IP network 200 in addition to the data of the channel requested by the video control unit 120 (step 1101). ) Is different from the first embodiment.

The video control unit 120 displays a list of data in the constant reception layer of the channel received from the IP control unit 110 (step 1102). For example, as shown in FIG. 18, if the data is "channel 1", "channel 2", and "channel 3", it is conceivable to divide the screen into three and display the video of each channel. In this case, when the viewer selects a video by operating a mouse or the like, a channel request for the selected channel, for example, channel 1 is transmitted to the IP control unit 110 (step 1103), as in the first embodiment. In addition, the IP control unit 110 receives the data of the additional layer during viewing of "channel 1" from the IP network 200 (step 1104), transfers the data to the video control unit 120 (step 1105), and the video control unit 120 "channel 1". It is also possible to play back the video.

According to the present embodiment, the images reproduced by the receiving device can be collectively displayed, and the convenience of channel selection is improved.

[Twelfth Embodiment]

In the present embodiment, when the IP control unit 110 receives a channel request from the video control unit 120 that requests data of only the constant reception layer, it acquires the data of the constant reception layer for the channel and transfers it to the video control unit 120. Then, the video control unit 120 describes an example of displaying the data in a list.

The configuration of the receiving device 100 and the contents of the hierarchical management table 130 in the present embodiment are the same as those in the first embodiment.

FIG. 19 is a sequence chart of the operation of the receiving device according to the twelfth embodiment of the present invention.

The video control unit 120 is the first embodiment in that the channel is selected by the channel when the data in the reception layer is always received.

For example, the IP control unit 110 of the receiving device 100 receives the data of the constant reception layer of "channel 1", "channel 2", and "channel 3" from the IP network 200, but the video control unit 120 receives "channel 1". When displaying only the data of "" and "channel 2", the video control unit 120 requests the IP control unit 110 for the constant reception layer of "channel 1" and the constant reception layer of "channel 2" (step 1201).

The video control unit 120 receives the data of the constant reception hierarchy of channel 1 and channel 2 from the IP control unit 110 (step 1202), divides the screen into two, and displays the video of each channel on the display device 500. indicate. (Step 1203).

According to the present embodiment, when the number of channels is large, the video reproduced only on the selected channel can be collectively displayed, and the processing capacity of the reception processing device can be improved.

[13th Embodiment]

In the present embodiment, the IP control unit 110 in the first to twelfth embodiments described above uses a multicast protocol as a distribution stop request to multicast a multicast participation request transmitted to the IP network 200 as a distribution request. Send a withdrawal request.

According to the video distribution system of the present embodiment, since a large number of channels are distributed to each receiving device, the bandwidth of the IP network can be effectively used by applying IP multicast.

[14th Embodiment]

In the present embodiment, when the IP network 200 uses the IP version 4, the IP control unit 110 transmits an IGMP version 3 Report message as a multicast join request and a multicast exit request. Alternatively, the IP control unit 110 transmits an IGMP version 2 Report message as a multicast join request, and transmits an IGMP version 2 Leave message as a multicast exit request.

Alternatively, when the IP network 200 uses IP version 6, the IP control unit 110 transmits an MLD version 2 Report message as a multicast join request and a multicast exit request. Alternatively, the IP control unit 110 transmits an MLS version 1 Report message as a multicast join request, and transmits an MLD version 1 Done message as a multicast exit request.

In this way, the standard IGMP and MLD can be used as the IP multicast protocol.

[Fifteenth Embodiment]

In this embodiment, when IGMP version 2 or MLD version 1 is used, a multicast address is used as a hierarchical identifier, and when IGMP version 3 or MLD version 2 is used, a combination of a multicast address and a source address is used as a hierarchical identifier. Is used. In this case, the source address is the IP address assigned to the distribution device.

According to the present embodiment, when multicast is used in an IP network, a multicast address or a combination of the multicast address and the source address, that is, the IP address assigned to the distribution device can be used as the hierarchical identifier. it can.

[16th Embodiment]

In this embodiment, configurations other than those described in FIGS. 3, 7, and 10 are shown.

In the receiving device shown in FIGS. 3, 7, and 10 described above, the IP control unit 110 and the hierarchical management table 130 are provided in the receiving device, but in the present embodiment, as shown in FIG. 20, IP control is provided. This is a configuration in which the receiving router 300 is provided with the unit 310 and the hierarchical management table 320.

The IP control unit 310 of the receiving router 300 is connected to a plurality of receiving devices 100 having the video control unit 120, and is also connected to the IP network 200.

The operation shown in the configuration shown in FIG. 20 is the same as that of the first to fifteenth embodiments described above, but the IP control unit 2310 of the receiving router 300 controls each video control unit 120 of the receiving device 100. To do. Therefore, when connecting a plurality of video control units 120 to the IP control unit 310, the channel switching monitoring timer is operated independently for each video control unit 120.

Further, in the configuration example of FIG. 21, a plurality of channel storage units 340 and a hierarchical management table 330 are connected to the IP control unit 310. When a plurality of video control units 120 are connected to the IP control unit 310, the channel storage unit 340 operates independently for each video control unit 120.

With the above configuration, the receiving device can commonly use the IP control unit by providing the reception control function (IP control unit) of the hierarchically coded data only in the receiving router.

In addition, the operations of the receiving device and the receiving router in each of the above embodiments may be constructed as a program, installed and executed on a computer used as the receiving device and the receiving router, or distributed via a network. It is possible.

The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

The present invention is applicable to a video distribution system in an IP network.

<figref num="1">It is a principle block diagram of this invention.</figref><figref num="2">It is a network configuration diagram in the 1st Embodiment of this invention.</figref><figref num="3">It is a block diagram of the receiving apparatus in 1st Embodiment of this invention.</figref><figref num="4">It is a block diagram of the hierarchical management table in 1st Embodiment of this invention.</figref><figref num="5">It is a sequence chart of the operation of the receiving apparatus in the 1st Embodiment of this invention.</figref><figref num="6">It is a sequence chart of the operation of the receiving apparatus in the 2nd Embodiment of this invention.</figref><figref num="7">It is a block diagram of the receiving apparatus in 3rd Embodiment of this invention.</figref><figref num="8">It is a sequence chart of the operation of the receiving apparatus in the 3rd Embodiment of this invention.</figref><figref num="9">It is a sequence chart of the operation of the receiving device in 4th Embodiment of this invention.</figref><figref num="10">It is a block diagram of the receiving apparatus in 5th Embodiment of this invention.</figref><figref num="11">It is a sequence chart (the 1) of the operation of the receiving apparatus in 5th Embodiment of this invention.</figref><figref num="12">It is a sequence chart (No. 2) of the operation of the receiving apparatus in the 5th Embodiment of this invention.</figref><figref num="13">It is a sequence chart of the operation of the receiving apparatus in the 6th Embodiment of this invention.</figref><figref num="14">It is a sequence chart of the operation of the receiving apparatus in 7th Embodiment of this invention.</figref><figref num="15">It is a sequence chart of the operation of the receiving apparatus in 8th Embodiment of this invention.</figref><figref num="16">It is a sequence chart of the operation of the receiving apparatus in the 9th Embodiment of this invention.</figref><figref num="17">It is a sequence chart of the operation of the receiving device in the tenth embodiment of this invention.</figref><figref num="18">It is a sequence chart of the operation of the receiving device in 11th Embodiment of this invention.</figref><figref num="19">It is a sequence chart of the operation of the receiving device in the twelfth embodiment of the present invention.</figref><figref num="20">It is a block diagram (the 1) of the receiving device and the receiving router in the 16th Embodiment of this invention.</figref><figref num="21">It is a block diagram (the 2) of the receiving device and the receiving router in the 16th Embodiment of this invention.</figref>

Code description

100 Receiver 110 IP control means, IP control 111 Channel switching status monitoring timer 120 Video control means, video control 130 Hierarchical management table 140 Channel storage 200 IP network 300 Receiving router 310 IP control 320 Hierarchical management table 400 Distribution device 500 Display means, display device