JP4609236B2 - Video distribution system and receiving router - Google Patents

Description

The present invention relates to a video distribution system及beauty receiving router, in particular, it relates to a video distribution system及beauty receiving router in IP networks.

  A conventional video distribution system applied to an IP network is composed of a distribution device and a reception device connected to the IP network. When unicast transfer is used in the IP network, the reception device makes a distribution request to the distribution device. The distribution device that has transmitted and received the distribution request encodes the video data and transmits the encoded video data to the reception device, and the reception device that receives the data decodes and reconstructs and displays the video.

Alternatively, when using multicast transfer in an IP network, the distribution device encodes the video data and distributes it multicast to the IP network, and the reception device is, for example, IGMP (Internet Group Management Protocol) or MLD (Multicast Listener Discovery) Using a multicast routing protocol such as the above, a distribution request is made to the IP network, the received data is decoded, reconstructed into a video, and displayed (for example, see Non-Patent Document 1).
Hiroyuki Ouchi, Hiroaki Sato, Ken Takahashi, Hiromitsu Nagata “A Study on Program Switching in IP Multicast”, Proceedings of Society Conference of IEICE, B-6-24

  However, in a conventional video distribution system using an IP network, all channels cannot be distributed to a receiving device, and it is difficult to realize broadcasting that distributes all channels 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 television or satellite broadcasting to 100 channels or more, a line of at least 120 Mbps to 600 Mbps or more is required per receiving device. In an IP network access line, even a 100 Mbps access line, which is a high-speed line using an optical fiber, has insufficient bandwidth.

  Furthermore, 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.

  For example, when using unicast transfer, a control signal is transmitted and received between the receiving device and the distribution device, a request to stop distributing data before switching, and a distribution request for data after switching are performed. Propagation delay and control processing delay in the distribution apparatus occur. Alternatively, in the case of IP multicast, since a multicast protocol control message is transferred between the receiving device and the router accommodating the receiving device, a propagation delay of the control message and a processing delay in the router occur.

  Due to the delay described above, when a channel is switched in a video distribution system using an IP network, it takes time until the video of the channel after switching is displayed after the viewer makes a switching request in the receiving device.

  Further, as described above, since channel switching takes time, the viewer may misrecognize that channel switching has failed. For this reason, the viewer repeatedly tries the channel switching request, and congestion may occur in the IP network or the distribution device.

The present invention has been made in view of the above, in the IP network, and an object thereof is to provide a video distribution system及beauty receiving router that enables a television broadcast by all channels transmitted by multicast.

  FIG. 1 is a principle configuration diagram of the present invention.

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,
The distribution apparatus 400 includes means for hierarchically encoding video data and transferring it to an IP network.
The receiving device 100
For each channel identifier, one or more layer identifiers from the lowest layer of data that is hierarchically encoded as a constantly receiving layer and a layer identifier higher than the constantly receiving layer are registered and stored as additional layers at the time of viewing. A hierarchy management table 130 as storage means;
A video control unit 120 that decodes the acquired data and composes and displays a video for the display unit 500 that the user views;
An IP control unit 110 connected to the IP network 200, the video control unit 120, and the hierarchy management table 130;
Have
The video control means 120
Means for transmitting a message of a channel request for requesting data of a channel to be displayed, a channel switching request, and a channel stop request to the IP control means 110;
Receiving data from the IP control means 110, decoding the received data to form a video, and displaying the data on the display means,
The IP control means 110
Means for receiving from the video control means 120 a message of a channel request, a channel switch request, and a channel stop request;
Based on the request from the video control means 120, the distribution request of the always receiving hierarchy of all the channels stored in the hierarchy management table and the additional hierarchy at the time of viewing of the channel requested from the video control means is IP Means for transmitting to the network 200, receiving data corresponding to the distribution request from the IP network 200, and transferring the data to the video control means 120.

The present invention (Claim 2) is the video distribution system according to Claim 1,
The IP control means 110
When a channel switching request is received from the video control means 120, the distribution stop request including the layer identifier of the additional layer at the time of viewing the channel before switching, which is acquired by referring to the layer management table 130, and the layer management table 130 are referred to. Means for transmitting the distribution request including the layer identifier of the additional layer when viewing the channel after switching acquired to the IP network;
Means for transferring the data of the constantly receiving layer of the post-switching channel corresponding to the distribution request from the IP network 200 and the data of the additional layer for viewing to the video control unit 120;
The video control means 120
When only the data of the always receiving layer is received from the IP control means 110, only the data of the always receiving layer is decoded and displayed as a video, or when the data of the always receiving layer is viewed When the data of the additional layer is received together, a means for decoding and displaying the data of the constantly receiving layer and the data of the additional layer at the time of viewing of the channel after switching to compose and display a video is included.

The present invention (Claim 3) is a video distribution system including a distribution device connected to an IP network, a reception router, and at least one reception device,
The distribution apparatus has means for hierarchically encoding video data and transferring it to an IP network,
The receiving device
For the display means for viewing by the user, it has video control means for decoding the acquired data and composing and displaying the video,
The receiving router
Connected to the IP network and the receiving device,
For each channel identifier, one or more layer identifiers from the lowest layer of data that is hierarchically encoded as a constantly receiving layer and a layer identifier higher than the constantly receiving layer are registered and stored as additional layers at the time of viewing. A hierarchy management table as a storage means;
An IP network, a video control unit of the receiving apparatus, and an IP control unit connected to the hierarchy management table;
Have
The video control means of the receiving device
Means for transmitting a message of a channel request for requesting channel data to be displayed, a channel switching request, and a channel stop request to the IP control means of the receiving router;
Receiving data from the IP control means, decoding the received data to compose a video, and displaying on the display means,
The IP control means of the receiving router is
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;
Based on the request from the video control means, the distribution request for the always receiving hierarchy of all the channels stored in the hierarchy management table and the additional hierarchy when viewing the channel requested from the video control means is sent to the IP network. And means for receiving data corresponding to the distribution request from the IP network and transferring the data to the video control means.

The present invention (Claim 4) is the video distribution system according to Claim 3,
The IP control means of the receiving router is
When a channel switching request is received from the video control means of the receiving apparatus, the distribution stop request including the layer identifier of the additional layer at the time of viewing the channel before switching acquired by referring to the layer management table and the layer management table are referred to Means for transmitting the distribution request including the layer identifier of the additional layer when viewing the channel after switching acquired to the IP network;
Means for transferring the data of the constantly receiving layer of the post-switching channel corresponding to the distribution request from the IP network and the data of the additional layer for viewing to the video control unit,
The video control means of the receiving device
When only the data of the constantly receiving layer is received from the IP control means of the receiving router, only the data of the constantly receiving layer is decoded and displayed as a video, or A means for decoding and displaying the always-received layer data and the additional layer data for viewing in the channel after switching when both of the additional layer data at the time of viewing are received. .

The present invention (Claim 5) is a receiving apparatus connected to a distribution apparatus connected to an IP network,
For each channel identifier, one or more layer identifiers from the lowest layer of data that is hierarchically encoded as a constantly receiving layer and a layer identifier higher than the constantly receiving layer are registered and stored as additional layers at the time of viewing. A hierarchy management table as a storage means;
A video control means for decoding the acquired data and composing and displaying the video for the display means for viewing by the user;
IP network, video control means, and IP control means connected to the hierarchy management table;
Have
The video control means
Means for transmitting a message of a channel request for requesting data of a channel to be displayed, a channel switching request, and a channel stop request to the IP control means;
Receiving data from the IP control means, decoding the received data to compose a video, and displaying on the display means,
IP control means
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 distribution request for the always receiving hierarchy of all the channels stored in the hierarchy management table and the additional hierarchy when viewing the channel requested from the video control means is sent to the IP network. And means for receiving data corresponding to the distribution request from the IP network and transferring the data to the video control means.

The present invention (Claim 6) is the receiving apparatus according to Claim 5,
IP control means
When a channel switching request is received from the video control means, the distribution stop request including the layer identifier of the additional layer at the time of viewing the channel before switching acquired with reference to the layer management table, and acquired with reference to the layer management table Means for transmitting a distribution request including a layer identifier of an additional layer at the time of viewing the channel after switching to the IP network;
Means for transferring the data of the constantly receiving layer of the post-switching channel corresponding to the distribution request from the IP network and the data of the additional layer for viewing to the video control unit,
The video control means
When only the data of the always receiving layer is received from the IP control means, only the data of the constantly receiving layer is decoded and displayed as a video, or added to the data of the always receiving layer and the viewing time In the case where both layers of data are received, there is included means for decoding the constantly received layer data and the additional layer data during viewing of the channel after switching, and constituting and displaying a video.

The present invention (Claim 7) is a distribution device connected to an IP network and a receiving router connected to at least one receiving device,
For each channel identifier, one or more layer identifiers from the lowest layer of data that is hierarchically encoded as a constantly receiving layer and a layer identifier higher than the constantly receiving layer are registered and stored as additional layers at the time of viewing. A hierarchy management table as a storage means;
An IP network, a video control unit of the receiving apparatus, and an IP control unit connected to the hierarchy management table;
Have
IP control means
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;
Based on the request from the video control means, the distribution request for the always receiving hierarchy of all the channels stored in the hierarchy management table and the additional hierarchy when viewing the channel requested from the video control means is sent to the IP network. And means for receiving data corresponding to the distribution request from the IP network and transferring the data to the video control means.

The present invention (Claim 8) is the receiving router according to Claim 7,
IP control means
When a channel switching request is received from the video control means of the receiving apparatus, the distribution stop request including the layer identifier of the additional layer at the time of viewing the channel before switching acquired by referring to the layer management table and the layer management table are referred to Means for transmitting the distribution request including the layer identifier of the additional layer when viewing the channel after switching acquired to the IP network;
Means for transferring the constantly received layer data of the post-switching channel corresponding to the distribution request from the IP network and the data of the additional layer during viewing to the video control unit;
Have

  As described above, according to the present invention, in the IP network, it is possible to perform television broadcasting by all-channel transfer by multicast, and it is possible to realize high-speed channel switching corresponding to user channel surfing.

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

[First embodiment]
FIG. 2 shows a network configuration in 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 an IP network 200 and a distribution device 400 is connected to the IP network 200.

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

  The receiving apparatus 100 shown in the figure includes an IP control unit 110, a video control unit 120, and a hierarchy management table 130, and the video control unit 120 and the hierarchy 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 hierarchy management table 130. In addition, the video control unit 120 receives messages such as a channel request, channel switching, and channel stop.

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

  The hierarchy management table 130 is configured by storage means such as a memory, and stores a channel identifier, a hierarchy number, a hierarchy identifier, and a hierarchy attribute as shown in FIG. 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 example, “1” is a basic layer, and numbers are assigned in order of “2” and “3”. The hierarchy identifier is an identifier in the IP network corresponding to the hierarchy number, and a multicast address or a combination of a multicast address and a source address can be considered. The layer attribute defines whether it is a constant reception layer or an additional layer during viewing. However, the example shown in FIG. 4 is a description for clarifying the explanation, 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.

  In addition, the always receiving layer and the viewing-time additional layer can each be composed of a plurality of layers.

  Next, the network operation 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 charts shown below, “Ch” indicates a channel, “always” indicates that the layer attribute is a constantly received layer, and “add” indicates that the layer attribute is an additional layer during viewing. Yes.

  Step 101) In the hierarchy management table 130, for example, data shown in FIG. 4 is registered.

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

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

  Step 104) Upon acquiring the hierarchy identifier request from the IP control unit 110, the hierarchy management table 130 returns the requested hierarchy identifier to the IP control unit 110. For example, “Channel 1” always receives “Hierarchy 1”, “230.0.0.1”, and “Channel 2” always receives “Hierarchy 1” and “230.0.10.1”. To do.

  Step 105) Next, the IP control unit 110 transmits a multicast participation request specifying “230.0.0.1” and “230.0.10.1” to the IP network 200. For example, in IGMPv3 and MLDv2, it is possible to transmit a “Report message” in which multicast addresses are collectively specified. Alternatively, when the hierarchy identifier is a combination of a multicast address and a source address, it is conceivable to transmit a “Report message” in which the combination of the multicast address and the source address is designated collectively.

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

  Step 107) The video control unit 120 first transmits a channel request for video to be displayed on the display device 500 to the IP control unit 110 automatically or by a viewer's operation. For example, it is assumed 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 a layer identifier request, for example, a 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 layer identifier of “channel 1” is acquired that the always receiving layer is “hierarchy 1” and “230.0.0.1”, and the viewing additional layer is “hierarchy 2” and “230.0.0.2”. To do.

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

  Step 111) When only the data of “Layer 1” is received from the IP controller 110, the image controller 120 decodes the image from only the data of “Layer 1”, and configures the display device of the user. 500.

  Step 112) Further, the IP control unit 110 transmits a multicast participation request specifying the layer identifier “230.0.0.2” to the IP network 200.

  Step 113) When the IP controller 110 starts to receive the data of the layer identifier “230.0.0.2” from the IP network 200, the data “230.0.0.2” and “layer 2” of “230.0.0.2” are “channel 1”. ”Is transferred to the video control unit 120.

  Step 114) After starting to receive the data of “Hierarchy 2”, the video controller 120 decodes the video from the data of “Hierarchy 1” and “Hierarchy 2”, configures it, and displays it on the display device 500.

  As described above, in the present embodiment, hierarchically encoded data is used, and video data is divided into a low bit rate constant reception layer and a viewing additional layer that improves video quality. In other words, the data of the minimum necessary hierarchy is distributed to all channel receiving apparatuses 100. Thereby, all the channels can be distributed to the receiving device 100. Furthermore, by distributing the data of the additional layer at the time of viewing for improving the video quality only for the necessary channels, the video quality equivalent to that of the television can be obtained.

  For example, even with 6 Mbps video data, if the constant reception layer is 500 kbps and the additional layer for viewing is 5.5 Mbps, even if the channel is always distributed and one channel is viewed, 55. A bandwidth of 5 Mbps is sufficient. Thereby, the same broadcasting as the television can be realized on the 100 Mbps access line.

[Second Embodiment]
In the present embodiment, a process when the IP control unit is requested to switch channels from the video control unit will be described.

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

  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 constantly receiving 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”, the video control unit 120 transmits a channel switching request to “channel 2” to the IP control unit 110.

  Step 203) Upon receiving the channel switching request from the video control unit 120, the IP control unit 110 changes the data to be 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 constantly receiving layer of “Channel 2”, but does not receive the data of the additional layer for viewing, and therefore transfers only the data of the constantly receiving layer. become.

  Step 204) In this case, the video control unit 120 reproduces the video of “Channel 2” only from the always receiving layer.

  Step 205) The IP control unit 110 transmits a multicast leaving request including the layer identifier “230.0.0.2” to stop the data of the additional layer at the time of viewing “Channel 1” to the IP network 200.

  Step 206) The IP control unit 110 requests a hierarchy identifier from the hierarchy management table 130 in order to acquire data of the additional hierarchy when viewing “Channel 2”.

  Step 207) The IP control unit 110 acquires “230.0.10.2” from the hierarchy management table 130 as the hierarchy identifier of the additional hierarchy when viewing “Channel 2”.

  Step 208) The IP control unit 110 transmits 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 when viewing “Channel 1”, a multicast participation request for the additional layer when viewing “Channel 2” is transmitted. Also good.

  Step 209) When the IP control unit 110 starts receiving the data “230.0.10.2” from the IP network 200, the data “230.0.10.2” and the data “230.0.10.2” are “channel 2”. “Level 2” is transferred to the video controller 120.

  Step 210) Thereafter, the video control unit 120 decodes and configures the video from the data of the constantly receiving layer of “Channel 2” and the additional layer of viewing, and displays the video on the display device 500.

  As described above, in this embodiment, the minimum data necessary for the video configuration is distributed in channel switching, and high-speed channel switching is possible within the receiving apparatus 100. Immediately after the channel is switched, data in the additional layer at the time of viewing is not received and there is a possibility that the image quality deterioration is recognized. However, if the data in the additional layer at the time of viewing is received, the video quality is improved. In addition, unlike the prior art, the minimum data required for the video configuration cannot be received, which is more effective than the video display cannot be performed at all.

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

  FIG. 7 shows the configuration of the receiving apparatus according to the third embodiment of the present invention. A difference from the configuration of FIG. 3 is that a 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 in 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 sends a channel switching request to “channel 2”. Send to.

  Step 303) At this time, the IP control unit 110 has received the data of the constantly receiving layer of “Channel 2”, but has not received the data of the additional layer at the time of viewing. Forward.

  Step 304) The video control unit 120 reproduces the video of “Channel 2” only from the always receiving layer.

  Step 305) The IP control unit 110 transmits a multicast leaving request including the layer identifier “230.0.0.2” to the IP network 200 in order to stop the data of the additional layer when viewing “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 state monitoring timer 111. The timer value is a predetermined value, and the present invention does not limit the timer value. As the timer value, the IP control unit 110 learns the viewer's channel switching request trap, and automatically sends the unnecessary layers to the IP network without receiving unnecessary messages 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 measurement samples equal to or less than a predetermined time and the margin time.

  Step 308) When the channel switching state monitoring timer 111 times out, the IP control unit 110 requests a hierarchy identifier from the hierarchy management table 130 in order to acquire data of the additional hierarchy when viewing “Channel 2”.

  Step 309) The IP control unit 110 obtains the additional tier identifier “230.0.10.2” during viewing of “Channel 2” from the tier management table 130.

  Step 310) The IP control unit 110 transmits a multicast participation request including the layer identifier “230.0.10.2” to the IP network 200.

  Step 311) When the IP control unit 110 starts receiving the data “230.0.10.2” from the IP network 200, the data of the layer identifier “230.0.10.2” and the data of the “230.0.10.2” are “channel 2”. The fact that it is “Layer 2” is transferred to the video controller 120.

  Step 312) After that, the video control unit 120 decodes the data of the constantly receiving layer and the additional layer of viewing of “Channel 2”, composes the video, and displays it on the display device 500.

  As described above, according to the present embodiment, a time interval is provided between the distribution stop process of the pre-switch channel and the distribution start process of the post-switch channel by timer monitoring at the time of channel switching. Or it becomes 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 during the operation of the channel switching state monitoring timer, the channel stored in the memory (not shown) is changed to the latest channel switching. An example will be described in which the channel is changed to the channel after the switching instructed by the request and the channel switching state monitoring timer is restarted.

  The configuration of the system and receiving apparatus 100 in the present embodiment is the same as that of 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 switching the channel 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 transmits a multicast leaving request to the IP network 200 in order to stop the data of the additional layer when viewing “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.

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

  Step 407) The video control unit 120 decodes the data of “Layer 1” of “Channel 2”, constructs a video, and plays it back on the display.

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

  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. To 110.

  Step 410) The IP control unit 110 restarts the channel switching state monitoring timer 111. Thereafter, when a channel switching request is received before the channel switching state monitoring timer 111 times out, the IP control unit 110 changes the channel identifier after channel switching stored in a memory (not shown).

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

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

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

  Step 414) The IP control unit 110 acquires the additional layer identifier “230.0.20.2” when viewing “Channel 3” from the layer management table 130.

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

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

  Step 417) Thereafter, the video control unit 120 decodes the data of the constantly receiving layer and the additional layer during viewing of “Channel 3”, composes the video, and displays it on the display device 500.

  As described above, according to the present embodiment, when monitoring a timer at the time of channel switching, continuous channel switching is performed in consideration of the operation that the viewer repeats channel switching temporarily, which is said to be channel surfing. It is possible to monitor and to suppress delivery message transmission when such continuous channel operation is performed. Further, it is effective for reducing the processing load of the distribution apparatus 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, instead of transmitting a distribution request specifying a layer identifier of the constantly receiving layer to the IP network, the always receiving layer is stored. An example of transmitting a distribution request designating a hierarchical identifier of will be described.

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

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

  FIG. 11 is a first sequence chart 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 a channel request and a channel switching request from the video control unit 120, if the data of the constantly receiving layer of the channel is being received, The same operation as in the embodiment 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 constantly receiving layer of the channel after switching is not received, the channel storage unit 140 stores the channel. Register. For example, when a channel switching request to “channel 3” is received from the video control unit 120, it is determined that the data of the constantly receiving layer of “channel 3” has not been received, and “channel 3” is stored in the channel storage unit 140. 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 hierarchy identifier of “channel 3” from the hierarchy management table 130, and acquires the hierarchy identifier.

  Step 513) With the channel switching from “Channel 2” to “Channel 3”, the IP control unit 110 transmits to the IP network 200 a multicast leaving request for the additional layer when viewing “Channel 2”.

  Step 514) Also, based on the hierarchy identifier (“channel 3”) acquired from the hierarchy management table 130, a multicast participation request is transmitted to the IP network 200.

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

  FIG. 12 is a sequence chart (part 2) of the system according to the fifth embodiment of the present invention.

  When the channel switching state monitoring timer 111 is used, the IP control unit 110 sets the timeout of the channel switching state monitoring timer 111 when receiving the channel switching request, as in steps 408 to 412 in the fourth embodiment described above. After waiting, it is determined whether or not the data of the constantly receiving layer of the channel after switching (for example, “Channel 3”) has not been received, and if it has not been received, “Channel 3”) is stored (steps 521 to 523).

  According to the present embodiment described above, when there are actually few channels to be viewed, not all channels including channels with low viewing frequency are distributed to the receiving device, but only recently displayed channels are received. By distributing to the device, the bandwidth used for the access line can be saved. For example, if the constant reception layer is 500 kbps, if the constant distribution is limited to 10 channels, a 5 Mbps bandwidth is sufficient for the access line, and the remaining bandwidth can be used effectively for other data transfer.

[Sixth Embodiment]
In the fifth embodiment described above, the channel is stored in the channel storage unit 140. However, in this embodiment, not only the channel but also the time when the channel is stored or the expiration date is stored in advance. An example in which channel / time information is deleted at the time when the time elapses will be described.

  The configuration of the receiving apparatus in this embodiment is the same as that of the fifth embodiment described above.

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

  When registering “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 predetermined time has elapsed (step 611).

  In addition, when registering “Channel 3” in the channel storage unit 140, the IP control unit 110 also registers the expiration date, and the channel storage unit 140 receives “Channel 3” when the finite expiration time arrives. You may delete the memory.

  As in this embodiment, caching recently displayed channel information reflecting the channel requested by the viewer is effective from the viewpoint of improving the control speed.

[Seventh 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 will be described in which the storage of the channel having the maximum time or the channel having the minimum time from the current time to the expiration date is deleted and a new channel is registered.

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

  FIG. 14 is a sequence chart of the operation of the receiving apparatus 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 registers “Channel 3” when registering “Channel 3” in the channel storage unit 140. ”Is registered in the channel storage unit 140, if the maximum number of channels is exceeded, the channel storage unit 140 stores the channel (for example,“ channel 1 ”) having the maximum time from the storage time to the current time. 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 that has been notified of the deletion of the storage of “channel 1” transmits a multicast leave request to the IP network 200 for the constantly receiving layer of “channel 1” (step 709). In this case, the multicast leave request for “channel 1” can be integrated into the same message as the multicast leave request for “channel 3” accompanying the channel switching from “channel 2” to “channel 3”.

  As in this embodiment, limiting the number of channels to be cached and deleting data with low usage frequency from the storage means is effective from the viewpoint of improving memory usage efficiency.

[Eighth Embodiment]
In the present embodiment, when the IP control unit 110 receives a channel request from the video control unit 120 and receives a channel switching request, the time when the channel storage unit 140 stores the channel is updated for the channel. An example will be described.

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

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

  When the IP control unit 110 receives a 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 always receiving layer is receiving or not receiving. (Step 802). If the channel with the registration request has been stored, the channel storage unit 140 updates the registration time or expiration date of the channel (step 803), and indicates that the channel has been registered (updated). (Step 804).

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

[Ninth Embodiment]
In this embodiment, an example in which the power supply is stopped / started when the above-described channel storage unit 140 is configured by a nonvolatile memory will be described.

  The configuration of this embodiment is the same as that of the fifth embodiment described above, but the channel storage unit 140 is a nonvolatile memory.

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

  The receiving apparatus 100 is currently stopped (step 901), and “channel 1” and “channel 2” are stored in the channel storage unit 140 (step 902). Further, it is assumed that the hierarchy identifiers of “channel 1”, “channel 2”, and “channel 3” are stored in the memory of the hierarchy management table 130 (step 903).

When the receiving apparatus 100 is activated (step 904), the IP control unit 110 reads a channel stored from the channel storage unit 140 (steps 905 and 906). For example, “Channel 1” and “Channel 2” are read out. Next, the IP control unit 110 reads out the layer identifiers of the constantly receiving layers of “Channel 1” and “Channel 2” from the layer management table 130 (Steps 907 and 908). ), A multicast participation request is transmitted to the IP channel 200 to the always receiving layer of “channel 1” and “channel 2” (step 909). As a result, data in the constantly receiving layer of “channel 1” and “channel 2” is transmitted from the IP network 200 (step 910).

  As in this embodiment, the final display channel is stored in the nonvolatile memory when the power is stopped, and the distribution request is made to the previous final display channel when the power is restarted. This is effective in simplifying and improving convenience.

[Tenth embodiment]
Also in the present embodiment, an example will be described in which the power supply is stopped / started when the channel storage unit 140 is configured by a nonvolatile memory in the ninth embodiment.

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

  The configuration of the receiving apparatus 100 and the contents of the hierarchy management table 130 in the present embodiment are the same as those in the fifth embodiment described above, but the channel storage unit 140 is a nonvolatile 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 nonvolatile memory (step 1002). Assume that the hierarchy identifiers of “channel 1”, “channel 2”, and “channel 3” are stored in the hierarchy management table 130 (step 1003).

  When the receiving apparatus 100 obtains the channel, for example, “channel 1”, which was last reproduced and displayed by the IP control unit 110 from the video control unit 120 during the stop process, the receiving apparatus 100 writes the “channel 1” in the channel storage unit 140 ( Step 1004, 1005).

  Next, at the time of activation, the receiving apparatus reads the channel and the channel (“channel 1”) that has been reproduced and displayed last from the channel storage unit 140 in the IP control unit 110 (steps 1006 and 1007). For example, when the channels stored in the channel storage unit 140 are “channel 1” and “channel 2”, and the channel reproduced and displayed last is “channel 1”, “channel 1” and “channel 2” are read out. .

  Next, the IP control unit 110 reads out the layer identifiers of the constantly receiving layer of “Channel 1”, the additional layer during viewing, and the constantly receiving layer of “Channel 2” from the layer management table 130 (Steps 1008 and 1009). A multicast participation request is transmitted to the IP network 200 for the always receiving layer of “Channel 1”, the additional layer for viewing and the always receiving layer of “Channel 2” (step 1010).

  When the IP control unit 110 receives the data of the always-received layer of “Channel 1” and the additional layer at the time of 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 and reproduced channel (Step 1012) ). Alternatively, if there is an explicit channel request from the video control unit 120 within a predetermined time from the start-up, the IP control unit 110 does not use the channel that was explicitly reproduced and displayed, but the channel that is explicitly requested. May be transferred to the video control unit 120.

  According to the present embodiment described above, the final display channel can be displayed to improve the convenience for the viewer, and only the recently displayed channel can be distributed to the receiving apparatus 100, thereby reducing the use band of the access line.

[Eleventh embodiment]
In the present embodiment, all the data of the constantly receiving layer received by the IP control unit 110 from the IP network 200 is transmitted to the video control unit 120, and each channel acquired from the IP control unit 110 in the video control unit 120 is transmitted. A description will be given of an example in which a video is composed of data of the regular reception layer and displayed as a list.

  The configuration of the receiving apparatus in this embodiment is the same as that in the first embodiment described above.

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

  The IP control unit 110 transmits to the video control unit 120 the data of the constantly receiving layer of all the channels received from the IP network 200 in addition to the data of the channel for which a channel request has been received from the video control unit 120 (step 1101). ) Is different from the first embodiment.

  The video control unit 120 displays a list of data of the constantly receiving layer of the channels 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 possible to divide the screen into three and display the video of each channel. In this case, when the viewer selects a video by operating the mouse or the like, a channel request of the selected channel, for example, “channel 1” is transmitted to the IP control unit 110 (step 1103), and the same as in the first embodiment. In addition, the IP control unit 110 receives the data of the additional layer at the time of viewing of “Channel 1” from the IP network 200 (Step 1104), transfers it to the video control unit 120 (Step 1105), and the video control unit 120 “Channel 1”. Can also be played.

  According to the present embodiment, it is possible to collectively display the images reproduced in the receiving apparatus, and the convenience of channel selection is improved.

[Twelfth embodiment]
In this embodiment, when the IP control unit 110 receives a channel request for requesting data of the always receiving layer only from the video control unit 120, the data of the always receiving layer is acquired for the channel and transferred to the video control unit 120. An example in which the video control unit 120 displays a list of the data will be described.

  The configuration of the receiving apparatus 100 and the contents of the hierarchy management table 130 in this embodiment are the same as those in the first embodiment.

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

  The video control unit 120 is different from the first embodiment in that the channel is selected according to the channel when the data of the constantly receiving layer is received.

  For example, the IP control unit 110 of the receiving apparatus 100 receives the data of the constantly receiving layer of “Channel 1”, “Channel 2”, and “Channel 3” from the IP network 200, but the video control unit 120 receives “Channel 1”. ] And “Channel 2” only, the video controller 120 requests the IP controller 110 for the “Channel 1” constant reception layer and the “Channel 2” constant reception layer (step 1201).

  The video control unit 120 receives the data of the constantly receiving layer 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, videos reproduced only for the selected channel can be displayed in a lump, and the processing capability of the reception processing device can be improved.

[Thirteenth embodiment]
In this embodiment, in IP control section 110 in the first to twelfth embodiments described above, a multicast participation request transmitted to IP network 200 as a distribution request is used as a distribution stop request using a multicast protocol. Send a leave request.

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

[Fourteenth embodiment]
In the present embodiment, when the IP network 200 uses IP version 4, the IP control unit 110 transmits an IGMP version 3 “Report message” as a multicast join request and a multicast leave request. Alternatively, the IP control unit 110 transmits an IGMP version 2 “Report message” as a multicast participation request, and transmits an IGMP version 2 “Leave message” as a multicast leave 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 leave request. Alternatively, the IP control unit 110 transmits an MLS version 1 “Report message” as a multicast participation request, and transmits an MLD version 1 “Done message” as a multicast withdrawal request.

  In this way, 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 layer identifier, and when IGMP version 3 or MLD version 2 is used, a combination of a multicast address and a source address as a layer identifier Is used. In this case, the source address is an IP address assigned to the distribution apparatus.

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

[Sixteenth embodiment]
In the present embodiment, configurations other than those shown in FIGS. 3, 7, and 10 are shown.

  In the receiving apparatuses shown in FIGS. 3, 7, and 10, the IP control unit 110 and the hierarchy management table 130 are provided in the receiving apparatus. However, in this embodiment, as shown in FIG. The receiving router 300 includes a unit 310 and a hierarchy management table 320.

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

  The operations shown in the configuration shown in FIG. 20 are the same as those in 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. Accordingly, when a plurality of video control units 120 are connected to the IP control unit 310, the channel switching monitoring timer is operated independently for each video control unit 120.

  In the configuration example of FIG. 21, a plurality of channel storage units 340 and a hierarchy 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 configuration as described above, by providing a reception control function (IP control unit) for hierarchically encoded data only in the receiving router, the receiving apparatus can commonly use the IP control unit.

  In addition, the operation of the receiving device and the receiving router in each of the above embodiments can 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. 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.

It is a principle block diagram of this invention. It is a network block diagram in the 1st Embodiment of this invention. It is a block diagram of the receiver in the 1st Embodiment of this invention. It is a block diagram of the hierarchy management table in the 1st Embodiment of this invention. It is a sequence chart of operation | movement of the receiver in the 1st Embodiment of this invention. It is a sequence chart of operation | movement of the receiver in the 2nd Embodiment of this invention. It is a block diagram of the receiver in the 3rd Embodiment of this invention. It is a sequence chart of the operation | movement of the receiver in the 3rd Embodiment of this invention. It is a sequence chart of operation | movement of the receiver in the 4th Embodiment of this invention. It is a block diagram of the receiver in the 5th Embodiment of this invention. It is a sequence chart (the 1) of operation | movement of the receiver in the 5th Embodiment of this invention. It is a sequence chart (the 2) of operation | movement of the receiver in the 5th Embodiment of this invention. It is a sequence chart of operation | movement of the receiver in the 6th Embodiment of this invention. It is a sequence chart of the operation | movement of the receiver in the 7th Embodiment of this invention. It is a sequence chart of the operation | movement of the receiver in the 8th Embodiment of this invention. It is a sequence chart of the operation | movement of the receiver in the 9th Embodiment of this invention. It is a sequence chart of operation | movement of the receiver in the 10th Embodiment of this invention. It is a sequence chart of operation | movement of the receiver in the 11th Embodiment of this invention. It is a sequence chart of the operation | movement of the receiver in the 12th Embodiment of this invention. It is a block diagram (the 1) of the receiver and receiving router in the 16th Embodiment of this invention. It is a block diagram (the 2) of the receiver and receiver in the 16th Embodiment of this invention.

Explanation of symbols

100 Receiving Device 110 IP Control Unit, IP Control Unit 111 Channel Switching State Monitoring Timer 120 Video Control Unit, Video Control Unit 130 Hierarchy Management Table 140 Channel Storage Unit 200 IP Network 300 Receiving Router 310 IP Control Unit 320 Hierarchy Management Table 400 Distribution Device 500 Display means, display device

Claims (8)

A video distribution system including a distribution device and a reception device connected to an IP (Internet Protocol) network,
The distribution device includes means for hierarchically encoding video data and transferring the video data to the IP network;
The receiving device is:
For each channel identifier, one or more layer identifiers from the lowest layer of data that is hierarchically encoded as a constantly receiving layer and a layer identifier higher than the constantly receiving layer are registered and stored as additional layers at the time of viewing. A hierarchy management table as a storage means;
A video control means for decoding the acquired data and composing and displaying the video for the display means for viewing by the user;
IP control means connected to the IP network, the video control means, and a hierarchy management table;
Have
The video control means includes
Means for transmitting a message of a channel request for requesting data of a channel to be displayed, a channel switching request, and a channel stop request to the IP control means;
Receiving data from the IP control means, decoding the received data to form a video, and displaying on the display means,
The IP control means includes
Means for receiving a message of the channel request, the channel switching request, and the channel stop request from the video control means;
Based on the request from the video control means, a distribution request for the always receiving hierarchy of all the channels stored in the hierarchy management table and the additional layer at the time of viewing the channel requested from the video control means is sent. Means for transmitting to the IP network, receiving data corresponding to the distribution request from the IP network, and transferring the data to the video control means;
A video distribution system comprising: The IP control means includes
When the channel switching request is received from the video control means, the distribution stop request including the layer identifier of the additional layer at the time of viewing the channel before switching, which is acquired by referring to the layer management table, and the layer management table is referred to Means for transmitting to the IP network a distribution request including a layer identifier of an additional layer when viewing the channel after switching acquired in
Means for transferring, from the IP network, data in the constantly receiving layer of the post-switching channel corresponding to the distribution request and data in the additional layer during viewing to the video control unit,
The video control means includes
When only the data of the always receiving layer is received from the IP control means, only the data of the always receiving layer is decoded and displayed as a video, or the data of the always receiving layer and the viewing And a means for decoding and displaying the constantly received layer data and the viewing additional layer data of the channel after switching and composing and displaying the video when the time additional layer data is received together. Item 2. The video distribution system according to Item 1. A video distribution system including a distribution device connected to an IP network, a reception router, and at least one reception device,
The distribution device includes means for hierarchically encoding video data and transferring the video data to the IP network;
The receiving device is:
For the display means for viewing by the user, it has video control means for decoding the acquired data and composing and displaying the video,
The receiving router is
Connected to the IP network and the receiving device;
For each channel identifier, one or more layer identifiers from the lowest layer of data that is hierarchically encoded as a constantly receiving layer and a layer identifier higher than the constantly receiving layer are registered and stored as additional layers at the time of viewing. A hierarchy management table as a storage means;
IP control means connected to the IP network, the video control means of the receiving device, and the hierarchy management table;
Have
The video control means of the receiving device is:
Means for transmitting a channel request requesting data of a channel to be displayed, a channel switching request, and a channel stop request message to the IP control means of the receiving router;
Receiving data from the IP control means, decoding the received data to form a video, and displaying on the display means,
The IP control means of the receiving router is:
Means for receiving the channel request, the channel switching request, and the channel stop request message from the video control means of the receiving device;
Based on the request from the video control means, a distribution request for the always receiving hierarchy of all the channels stored in the hierarchy management table and the additional layer at the time of viewing the channel requested from the video control means is sent. Means for transmitting to the IP network, receiving data corresponding to the distribution request from the IP network, and transferring the data to the video control means;
A video distribution system comprising: The IP control means of the receiving router is:
A distribution stop request including a layer identifier of an additional layer at the time of viewing the channel before switching, obtained by referring to the layer management table when the channel switching request is received from the video control means of the receiving device; Means for transmitting to the IP network a distribution request including a layer identifier of an additional layer when viewing the channel after switching acquired with reference to the management table;
Means for transferring, from the IP network, data in the constantly receiving layer of the post-switching channel corresponding to the distribution request and data in the additional layer during viewing to the video control unit,
The video control means of the receiving device is:
When only the data of the constantly receiving layer is received from the IP control means of the receiving router, only the data of the constantly receiving layer is decoded and displayed as a video, or When both the data and the data of the additional layer for viewing are received, the data of the constantly receiving layer and the data of the additional layer for viewing of the channel after switching are decoded, and the video is configured and displayed. 4. The video distribution system according to claim 3, further comprising means. A receiving device connected to a distribution device connected to an IP network,
For each channel identifier, one or more layer identifiers from the lowest layer of data that is hierarchically encoded as a constantly receiving layer and a layer identifier higher than the constantly receiving layer are registered and stored as additional layers at the time of viewing. A hierarchy management table as a storage means;
A video control means for decoding the acquired data and composing and displaying the video for the display means for viewing by the user;
IP control means connected to the IP network, the video control means, and a hierarchy management table;
Have
The video control means includes
Means for transmitting a message of a channel request for requesting data of a channel to be displayed, a channel switching request, and a channel stop request to the IP control means;
Receiving data from the IP control means, decoding the received data to form a video, and displaying on the display means,
The IP control means includes
Means for receiving a message of the channel request, the channel switching request, and the channel stop request from the video control means;
Based on the request from the video control means, a distribution request for the always receiving hierarchy of all the channels stored in the hierarchy management table and the additional layer at the time of viewing the channel requested from the video control means is sent. Means for transmitting to the IP network, receiving data corresponding to the distribution request from the IP network, and transferring the data to the video control means;
A receiving apparatus comprising: The IP control means includes
When the channel switching request is received from the video control means, the distribution stop request including the layer identifier of the additional layer at the time of viewing the channel before switching, which is acquired by referring to the layer management table, and the layer management table is referred to Means for transmitting to the IP network a distribution request including a layer identifier of an additional layer when viewing the channel after switching acquired in
Means for transferring, from the IP network, data in the constantly receiving layer of the post-switching channel corresponding to the distribution request and data in the additional layer during viewing to the video control unit,
The video control means includes
When only the data of the always receiving layer is received from the IP control means, only the data of the always receiving layer is decoded and displayed as a video, or the data of the always receiving layer and the viewing And a means for decoding and displaying the constantly received layer data and the viewing additional layer data of the channel after switching and composing and displaying the video when the time additional layer data is received together. Item 6. The receiving device according to Item 5. A distribution device connected to the IP network, and a receiving router connected to at least one receiving device,
For each channel identifier, one or more layer identifiers from the lowest layer of data that is hierarchically encoded as a constantly receiving layer and a layer identifier higher than the constantly receiving layer are registered and stored as additional layers at the time of viewing. A hierarchy management table as a storage means;
IP control means connected to the IP network, the video control means of the receiving device, and the hierarchy management table;
Have
The IP control means includes
Means for receiving the channel request, the channel switching request, and the channel stop request message from the video control means of the receiving device;
Based on the request from the video control means, a distribution request for the always receiving hierarchy of all the channels stored in the hierarchy management table and the additional layer at the time of viewing the channel requested from the video control means is sent. Means for transmitting to the IP network, receiving data corresponding to the distribution request from the IP network, and transferring the data to the video control means;
A receiving router. The IP control means includes
A distribution stop request including a layer identifier of an additional layer at the time of viewing the channel before switching, obtained by referring to the layer management table when the channel switching request is received from the video control means of the receiving device; Means for transmitting to the IP network a distribution request including a layer identifier of an additional layer when viewing the channel after switching acquired with reference to the management table;
Means for transferring, from the IP network, data of the constantly receiving layer of the post-switching channel corresponding to the distribution request and data of the additional layer during viewing to the video control unit;
The receiving router according to claim 7.

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