JP7255301B2 - Switching method, IP retransmission system, IP retransmission device and control device - Google Patents

Description

The present disclosure relates to a switching method, an IP retransmission system, an IP retransmission device and a control device.

2. Description of the Related Art Along with recent improvements in digital technology, services that provide more programs by applying digital technology to television broadcasting and the like are being provided. High-efficiency compression and multiplexing techniques are used to provide more programs with high image quality and sound quality using a limited transmission band.

As an example of such a digital broadcasting system, for example, Japanese Patent Application Laid-Open No. 2010-171799 (Patent Document 1) discloses the following configuration. That is, the re-multiplexing system includes a demodulator that receives and demodulates digital broadcast waves and outputs MPEG-2 TS (Transport Stream), and MPEG-2 TS is input from the demodulator and converts MPEG-2 video of multiple channels. A plurality of video transcoders that perform transcoding on each target, multiplex the video after transcoding, the audio and subtitles in the digital broadcast signal, and the PCR (Program Clock Reference) in MPEG-2 TS format and output them. and a remultiplexer for remultiplexing the transcoder output signals of the plurality of video transcoders and the MPEG-2 TS output of the demodulator. The remultiplexing device receives transcoder output signals from the plurality of video transcoders, extracts TS packets of MPEG-2 TS from the received signals, and writes them into a signal buffer area of the signal storage means. a transcoder output signal receiving means for receiving MPEG-2 TS output from said demodulator, extracting TS packets of MPEG-2 TS from said received signal, and writing them to a signal buffer area of signal storage means PCR in TS packets of MPEG-2 TS written in signal storage means by signal reception means, and MPEG-2 TS written in signal storage means by said broadcast signal reception means time stamp value for determining the multiplex timing of the TS packets of MPEG-2 TS received from the video transcoder and the TS packets of MPEG-2 TS received from the demodulator, based on the PCR in the TS packets of is obtained for each TS packet, and the multiple timing control means for writing the time stamp value together with each TS packet into the signal storage means; multiplexing means for reading out the TS packets in the signal storage means at timing, remultiplexing the transcoder output signal and the digital broadcast signal, and outputting them.

Also, a technique for transmitting content using MMTP (MPEG Media Transport Protocol) packets has been developed.

For example, Non-Patent Document 1 (Association of Radio Industries and Businesses, “Media Transport Method by MMT in Digital Broadcasting ARIB STD-B60 Version 1.9”, March 24, 2017) describes broadcasting using the MMT method A system is disclosed.

In this broadcasting system, MMT packets containing program information such as audio information and video information are stored in IP packet payloads. An IP packet is stored in the payload of a TLV (Type Length Value) packet.

JP 2010-171799 A

Association of Radio Industries and Businesses, “Media transport method by MMT in digital broadcasting ARIB STD-B60 Version 1.9”, March 24, 2017 Association of Radio Industries and Businesses, "Transmission method for advanced broadband satellite digital broadcasting ARIB STD-B44 Version 2.1", March 25, 2016 International Telecommunication Union Radiocommunications Sector, ``Recommendation ITU-R BT. itu. int/dms_pubrec/itu-r/rec/bt/R-REC-BT. 1869-0-201003-I! ! PDF-E. pdf> "JCTEA STD-002-6.0 Digital Cable Television Broadcast Multiplexing Equipment", Japan CATV Engineering Association

2. Description of the Related Art In many cases, a plurality of active and standby distribution devices are installed in a station building of a distributor of digital broadcasting such as cable television.

In such a distribution device, in order to absorb fluctuations in the transmission time of packets in the network in the playback device, there is a case where information on the timing at which the packet should be processed is included in the packet and transmitted.

Here, when the output of the distribution device is stopped and the distribution is switched to the standby distribution device for maintenance replacement of the active distribution device, if the information contained in the packet received by the reproduction device is disturbed, It becomes difficult to reproduce the content satisfactorily.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. A retransmission system, an IP retransmission device and a control device are provided.

A switching method according to the present disclosure operates retransmission of content in an IP retransmission system including a plurality of IP retransmission devices that receive broadcast waves and retransmit IP packets containing content included in the broadcast waves. A switching method for switching from the IP retransmission device of the system to the IP retransmission device of the standby system, wherein the frequency of the broadcast wave received by the IP retransmission device of the operation system is changed to the IP retransmission device of the standby system. a first count based on synchronization information for time synchronization that can be acquired by each IP retransmission device, which is information generated in the active IP retransmission device; and a second count value indicating the processing timing of the content reproducing device to the standby IP retransmitting device; a step of switching retransmission of the content from a transmission device to the standby IP retransmission device; and sending.

An IP retransmission system according to the present disclosure includes a plurality of IP retransmission devices that receive the same broadcast wave from a distributor and retransmit IP packets containing content included in the broadcast wave; The IP packet output from the IP retransmission device is relayed by a relay device and transmitted to the network, and the standby IP retransmission device changes the frequency of the received broadcast wave to the active IP retransmission device. According to the frequency of the broadcast wave received by the device, the standby IP retransmitting device receives information generated by the active IP retransmitting device, which is the time that can be acquired by each of the IP retransmitting devices. acquiring timing information including a difference between a first count value based on synchronization information for synchronization and a second count value indicating processing timing in the content reproduction device via the control device, the control device comprising: and switching retransmission of the content by causing the active IP retransmission device to stop retransmission of the content at a predetermined timing, and causing the standby IP retransmission device to retransmit the content at a predetermined timing. , and the IP retransmitting device of the switching destination includes the processing timing based on the given timing information in the IP packet and transmits it.

An IP retransmission device of the present disclosure is an IP retransmission device in an IP retransmission system that receives a broadcast wave and retransmits content included in the broadcast wave by including it in an IP packet, wherein each of the IP retransmission devices a timing information generating unit that generates timing information including a difference between a first count value based on the synchronization information for time synchronization that can be acquired in and a second count value that indicates the processing timing of the content reproduction device; a notification unit that notifies the other IP retransmission device of the timing information generated by the timing information generation unit; an acquisition unit that acquires the timing information notified from the other IP retransmission device; a packet processing unit that generates and transmits the IP packet including the processing timing based on the timing information acquired by the unit.

A control device according to the present disclosure is a control device in an IP retransmission system including a plurality of IP retransmission devices that receive broadcast waves, include content included in the broadcast waves in IP packets, and retransmit IP packets, a broadcast wave command unit for notifying the IP retransmission device of of a command to match the frequency of the broadcast wave to be received with the frequency of the broadcast wave received by the IP retransmission device of the operation system; A first count value based on synchronization information for time synchronization that can be acquired by each IP retransmission device, which is information generated in the IP retransmission device of the above; an acquisition unit that acquires timing information including a difference from the count value of the active system at a predetermined timing a switching command unit for notifying a command for the IP retransmitting device of the above to stop retransmitting the content and for the IP retransmitting device of the standby system to start retransmitting the content at a predetermined timing.

One aspect of the present disclosure can be implemented not only as an IP retransmission system including such a characteristic processing unit, but also as a program for causing a computer to execute steps of such characteristic processing. Also, one aspect of the present disclosure may be implemented as a semiconductor integrated circuit that implements part or all of the IP retransmission system.

One aspect of the present disclosure can be implemented not only as an IP retransmission device including such a characteristic processing unit, but also as a switching method having steps of such characteristic processing, can be implemented as a program for executing Also, one aspect of the present disclosure can be implemented as a semiconductor integrated circuit that implements part or all of the IP retransmission device.

One aspect of the present disclosure can be realized not only as a control device including such a characteristic processing unit, but also as a control method having such characteristic processing as steps, or as a control method in which such steps are executed by a computer. It can be realized as a program for making Also, one aspect of the present disclosure can be implemented as a semiconductor integrated circuit that implements part or all of the control device.

According to the present disclosure, it is possible to realize stable content reproduction in a reproduction device in a configuration in which a content transmission device can be switched.

FIG. 1 is a diagram showing the configuration of an IP retransmission system according to an embodiment of the present disclosure. FIG. 2 is a diagram showing an example protocol stack of data transmitted by a broadcast signal in the IP retransmission system according to the embodiment of the present disclosure. FIG. 3 is a diagram showing an example of TLV packets transmitted by broadcast signals in the IP retransmission system according to the embodiment of the present disclosure. FIG. 4 is a diagram showing the configuration of an IP retransmission device in the IP retransmission system according to the embodiment of the present disclosure. FIG. 5 is a diagram showing an example of NTP data in NTP length format in the IP retransmission system according to the embodiment of the present disclosure. FIG. 6 is a diagram illustrating an example of a TLV packet division method performed in the IP retransmission device according to the embodiment of the present disclosure. 7 is a diagram showing an example of the format of the TS packet shown in FIG. 6. FIG. FIG. 8 is a diagram illustrating processing when switching IP retransmission devices by the IP retransmission system according to the embodiment of the present disclosure. FIG. 9 is a diagram illustrating an example of a sequence of switching processing of IP retransmission devices by the IP retransmission system according to the embodiment of the present disclosure. FIG. 10 is a diagram showing the configuration of a control device in the IP retransmission system according to the embodiment of the present disclosure. FIG. 11 is a diagram showing a configuration of a modification of the IP retransmission device in the IP retransmission system according to the embodiment of the present disclosure.

First, the contents of the embodiments of the present disclosure will be listed and described.

(1) A switching method according to an embodiment of the present disclosure is provided in an IP retransmission system including a plurality of IP retransmission devices that receive broadcast waves and retransmit IP packets containing content included in the broadcast waves. A switching method for switching retransmission of the content from the active IP retransmitting device to the standby IP retransmitting device, wherein the frequency of a broadcast wave received by the active IP retransmitting device a step of matching the frequency of the broadcast wave received by the standby IP retransmission device; giving timing information including a difference between a first count value based on synchronization information and a second count value indicating processing timing in the content reproduction device to the standby IP retransmission device; and a predetermined timing. a step of switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device; and transmitting timing in said IP packet.

With this method, compared to the case where the output stop timing of the active IP retransmitting device and the output start timing of the standby IP retransmitting device are simply switched together, the IP retransmitting device of the switching destination can be It is possible to stably process the IP packets transmitted from the transmitting device and reproduce the content satisfactorily. In addition, by using the synchronization information that can be acquired by each IP retransmission device, it is possible to avoid the influence of the transmission delay of the timing information from the active IP retransmission device to the standby IP retransmission device. Therefore, in a configuration in which the content transmission device can be switched, it is possible to realize stable content reproduction in the reproduction device.

(2) Preferably, the count frequency of the first count value and the count frequency of the second count value are different, and the timing information further includes the first count value from which the difference is calculated. , the switching method is further characterized in that the IP retransmission device to be switched to is based on the difference and the first count value included in the timing information and the count value based on the synchronization information acquired by itself. and calculating the processing timing.

With such a method, in a system in which the frequency of each count value is different, the timing of the second count value in the active IP retransmission device and the second count value in the standby IP retransmission device can be easily matched. can be done.

(3) Preferably, the synchronization information is NTP (Network Time Protocol) data included in the broadcast wave, and the processing timing is a time stamp included in a TTS (Time-stamped TS) packet.

With this method, in a system that provides an IP retransmission service for transmitting advanced broadband satellite digital broadcasting to subscribers' homes via an IPTV transmission network, NTP data can be effectively used, and from the IP retransmission device to which switching is to be made. It is possible to stably process IP packets to be transmitted and to reproduce contents satisfactorily.

(4) An IP retransmission system according to an embodiment of the present disclosure includes a plurality of IP retransmission devices that receive the same broadcast wave from a distributor and retransmit IP packets containing content included in the broadcast wave. , and a control device, wherein the IP packet output from each IP retransmission device is relayed by a relay device and transmitted to a network, and the standby IP retransmission device adjusts the frequency of the broadcast wave to be received. , according to the frequency of the broadcast wave received by the active IP retransmitting device, the standby IP retransmitting device is information generated in the active IP retransmitting device, each of the IP Timing information including a difference between a first count value based on the synchronization information for time synchronization that can be acquired by the retransmission device and a second count value indicating the processing timing of the content reproduction device is transmitted via the control device. The control device causes the active IP retransmission device to stop retransmission of the content at a predetermined timing, and causes the standby IP retransmission device to stop retransmission of the content at a predetermined timing. and the switching destination IP retransmission device transmits the IP packet including the processing timing based on the given timing information.

With such a configuration, compared to the case where the output stop timing of the active IP retransmitting device and the output start timing of the standby IP retransmitting device are simply switched together, the IP retransmitting device of the switching destination can be It is possible to stably process the IP packets transmitted from the transmitting device and reproduce the content satisfactorily. In addition, by using the synchronization information that can be acquired by each IP retransmission device, it is possible to avoid the influence of the transmission delay of the timing information from the active IP retransmission device to the standby IP retransmission device. Therefore, in a configuration in which the content transmission device can be switched, it is possible to realize stable content reproduction in the reproduction device.

(5) An IP retransmission device according to an embodiment of the present disclosure is an IP retransmission device in an IP retransmission system that receives broadcast waves and retransmits IP packets containing content included in the broadcast waves. and timing information including a difference between a first count value based on synchronization information for time synchronization that can be acquired in each IP retransmission device and a second count value indicating processing timing in the content reproduction device. a timing information generating unit for generating; a notifying unit for notifying the other IP retransmitting device of the timing information generated by the timing information generating unit; and the timing information notified from the other IP retransmitting device. An acquisition unit for acquiring, and a packet processing unit for generating and transmitting the IP packet including the processing timing based on the timing information acquired by the acquisition unit.

With such a configuration, compared to the case where the output stop timing of the active IP retransmitting device and the output start timing of the standby IP retransmitting device are simply switched together, the IP retransmitting device of the switching destination can be It is possible to stably process the IP packets transmitted from the transmitting device and reproduce the content satisfactorily. In addition, by using the synchronization information that can be acquired by each IP retransmission device, it is possible to avoid the influence of the transmission delay of the timing information from the active IP retransmission device to the standby IP retransmission device. Therefore, in a configuration in which the content transmission device can be switched, it is possible to realize stable content reproduction in the reproduction device.

(6) A control device according to an embodiment of the present disclosure is an IP retransmission system that includes a plurality of IP retransmission devices that receive broadcast waves and retransmit IP packets containing content included in the broadcast waves. A control device that notifies the IP retransmission device of the standby system of a command to match the frequency of the broadcast wave to be received with the frequency of the broadcast wave received by the IP retransmission device of the operation system. a first count value based on synchronization information for time synchronization that can be acquired by each IP retransmission device, which is information generated in the active IP retransmission device; and reproduction of the content. an acquisition unit that acquires timing information including a difference from a second count value indicating processing timing in the device; and an information addition unit that provides the timing information acquired by the acquisition unit to the standby IP retransmission device. , the active IP retransmission device stops retransmission of the content at a predetermined timing, and the standby IP retransmission device notifies an instruction to start retransmission of the content at a predetermined timing; and an instruction unit.

With such a configuration, compared to the case where the output stop timing of the active IP retransmitting device and the output start timing of the standby IP retransmitting device are simply switched together, the IP retransmitting device of the switching destination can be It is possible to stably process the IP packets transmitted from the transmitting device and reproduce the content satisfactorily. In addition, by using the synchronization information that can be acquired by each IP retransmission device, it is possible to avoid the influence of the transmission delay of the timing information from the active IP retransmission device to the standby IP retransmission device. Therefore, in a configuration in which the content transmission device can be switched, it is possible to realize stable content reproduction in the reproduction device.

Embodiments of the present disclosure will be described below with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. Moreover, at least part of the embodiments described below may be combined arbitrarily.

[composition]
FIG. 1 is a diagram showing the configuration of an IP retransmission system according to an embodiment of the present disclosure.

Referring to FIG. 1, the IP retransmission system 301 is, for example, the Association of Radio Industries and Businesses, "Transmission method for advanced broadband satellite digital broadcasting ARIB STD-B44 Version 2.1", March 25, 2016 (non- An IP retransmission system that complies with broadcast wave standards such as advanced broadband satellite digital broadcasting according to the method disclosed in Patent Document 2), and includes a plurality of IP retransmission devices 101, one or a plurality of control devices 151, and a distributor. 152 , an L2 switch 153 and an L3 switch 155 . Note that IP retransmission system 301 may be an IP retransmission system conforming to other standards.

In FIG. 1, as an example, 15 IP retransmitting devices 101 are provided as the active system, 2 IP retransmitting devices 101 are the standby system, and 2 control devices 151 are provided as the active system and the standby system. there is Note that the L2 switch 153 and the L3 switch 155 are each realized by one device or multiple devices.

The IP retransmitting device 101 receives a broadcast wave including a stream containing content, and retransmits IP packets containing the content and the like included in the received broadcast wave. More specifically, distributor 152 distributes the broadcast signal received at antenna 81 to each IP retransmission device 101 .

The stream includes content, that is, program information and the like. Program information includes, for example, audio information, video information, EPG (Electronic Program Guide) information, SI information (Service Information), caption information, and the like.

FIG. 2 is a diagram showing an example protocol stack of data transmitted by a broadcast signal in the IP retransmission system according to the embodiment of the present disclosure. In FIG. 2, a protocol stack using TLV packets is shown.

Referring to FIG. 2, TLV packets are often used for transmission of 4K UHDTV (Ultra High Definition Television) or 8K UHDTV according to standards such as 2160p or 4320p.

In the example shown in FIG. 2, the broadcast wave includes, for example, TMCC (Transmission & Multiplexing Configuration Control) information, AC information and TLV packets.

FIG. 3 is a diagram showing an example of TLV packets transmitted by broadcast signals in the IP retransmission system according to the embodiment of the present disclosure. FIG. 3 shows an example of a packet having a header storing information indicating a data type, International Telecommunication Union Radiocommunications Sector, "Recommendation ITU-R BT.1869", March 2010, [online], [Heisei Retrieved March 8, 2019], Internet <URL: http://www. itu. int/dms_pubrec/itu-r/rec/bt/R-REC-BT. 1869-0-201003-I! ! PDF-E. pdf> (Non-Patent Document 3).

A TLV packet includes a TLV header and a TLV payload. The TLV header includes a 'start code' field with a value of '01', a 'future reserved' field, a 'packet type' field, and a 'length' field. are 2 bits, 6 bits, 8 bits and 16 bits respectively.

A value such as “0x01”, “0x02”, “0x03” or “0xFF” is stored in the “packet type” field. Here, the numbers starting with "0x" mean that the numbers after "0x" are represented in hexadecimal.

When "0x01" is stored in the "packet type" field, the TLV packet 61 includes an IPv4 packet whose total data length is the value stored in the "length" field in the TLV payload.

When "0x02" is stored in the "packet type" field, the TLV packet 62 includes an IPv6 packet whose total data length is the value stored in the "length" field in the TLV payload.

When "0x03" is stored in the "packet type" field, the TLV packet 63 includes an IP packet whose total data length is the value stored in the "length" field in the TLV payload. A compressed IP packet is, for example, an IP packet whose IP header is compressed.

Also, when "0xFF" is stored in the "packet type" field, the TLV packet 64 includes null data that is the total data length of the value stored in the "length" field in the TLV payload. Hereinafter, a TLV packet containing null data in the TLV payload is also referred to as a TLV null packet.

Referring to FIG. 2 again, for example, NTP (Network Time Protocol) data for time synchronization, IP-SI data, time information, MMT packets, or data transmission methods are stored in UDP (User Datagram Protocol)/IP packets. be done. MMT packets contain video information, audio information, MMT-SI data, and other information.

TLV packets 61 to 63 (hereinafter also referred to as TLV information packets) store such UDP/IP packets.

In addition, it is stipulated that one or more streams forming a frame are included in a broadcast wave. Multiple streams can be efficiently transmitted by using broadcast waves to transmit streams while maintaining the frame structure.

A frame can contain multiple streams, each corresponding to a program from up to 16 stations. Each stream is distinguished, for example, by using the transport stream ID contained in the MMT packet in the TLV packet.

Referring to FIG. 1 again, IP retransmitting apparatus 101 extracts content information, ie, program information, from the broadcast signal received from distributor 152, and divides the extracted content information into a plurality of IP packets containing, for example, Multicast to each IP-STB 171 via L3 switch 155 and IP network 401 . That is, IP packets output from each IP retransmission device 101 are relayed by the L3 switch 155, which is an example of a relay device, and transmitted to the IP network 401. FIG. For example, IP retransmitting device 101 retransmits the information obtained by dividing the content into one or more IP packets.

The IP-STB 171 is an example of a content reproduction device, extracts content information from each IP packet received from the IP network 401, and reproduces it on a television device (TV) 172. FIG.

IP retransmission device 101 transmits SI information of the corresponding station to all-station SI (Service Information) server 161 via L2 switch 153 .

IP retransmission device 101 also extracts emergency information such as an emergency alert from the broadcast signal received from distributor 152 and transmits the information to emergency alert server 162 via L2 switch 153 .

The control device 151 performs settings and monitoring of the IP retransmission device 101 by transmitting and receiving information to and from the IP retransmission device 101 via the L2 switch 153 .

FIG. 4 is a diagram showing the configuration of an IP retransmission device in the IP retransmission system according to the embodiment of the present disclosure.

Referring to FIG. 4, IP retransmission device 101 includes tuner 11, control section (timing information generation section, notification section and acquisition section) 18, counters 19A and 19B, switch circuit 20, and high-precision oscillator 21. , a packet processing unit 22 , a multiplier circuit 23 , an NTP packet acquisition unit 24 , a conversion unit 25 , a deletion unit 26 and a TS conversion unit 27 . Packet processing unit 22 includes IP conversion unit 17 and TTS conversion unit 28 .

High accuracy oscillator 21 generates, for example, a reference clock. More specifically, the high-precision oscillator 21 is an oscillator that generates a high-precision clock pulse of 27 MHz synchronized with time information included in radio waves transmitted from, for example, GPS (Global Positioning System) satellites. High accuracy oscillator 21 outputs the generated clock pulse to counter 19B and multiplier circuit 23 .

The multiplier circuit 23 outputs a multiplied clock obtained by multiplying the reference clock received from the high-accuracy oscillator 21 by a predetermined number to the counter 19A. Specifically, the multiplier circuit 23 multiplies the reference clock to generate a clock pulse of 2̂32 Hz, and outputs the generated clock pulse to the counter 19A. Here, "a^b" means a to the power of b.

The high-precision oscillator 21 may be configured to generate a high-precision clock pulse using an OCXO (Oven Controlled Oscillator), a rubidium oscillator, or the like.

Counter 19A updates the count value according to the timing of the multiplied clock received from multiplication circuit 23, for example. Counter 19B updates the count value according to the timing of the reference clock received from high-precision oscillator 21, for example.

More specifically, the counter 19A counts the pulses of the multiplied clock received from the multiplication circuit 23 and holds the count value.

The counter 19B counts the pulses of the reference clock received from the high accuracy oscillator 21 and holds the count value.

Broadcast waves in the IP retransmission system 301 are transmitted between devices using the above-mentioned TLV null packets, variable-sized packets containing program information, that is, data-sized variable packets, and Coordinated Universal Time (UTC). includes synchronization information for time synchronization in and conforms to the MMT scheme.

Here, the TLV packet is an example of a variable packet. NTP data is an example of synchronization information for time synchronization that can be acquired by IP retransmission device 101 .

The control unit 18 sets and monitors each unit in the IP retransmission device 101 , and transmits and receives various information to and from the control device 151 .

The tuner 11 demodulates the broadcast signal of the frequency specified by the control unit 18 among the broadcast signals received from the distributor 152, thereby including TLV null packets, TLV program packets, and time adjustment information. Generate a stream.

More specifically, tuner 11 demodulates the broadcast signal received from distributor 152 to generate a stream composed of a plurality of TLV packets (see FIG. 2). In the stream, for example, NTP data is transmitted every 33 milliseconds.

Tuner 11 outputs the generated stream to NTP packet acquisition section 24 and deletion section 26 .

The NTP packet acquisition unit 24 receives the stream from the tuner 11 , acquires IP packets containing NTP data (hereinafter also referred to as NTP packets) from the received stream, and outputs the acquired NTP packets to the conversion unit 25 .

The conversion unit 25 uses, for example, NTP data included in the broadcast wave to set the time for the counter 19A.

More specifically, the conversion unit 25 receives an NTP packet from the NTP packet acquisition unit 24 and acquires Coordinated Universal Time in NTP length format from the NTP data included in the received NTP packet.

FIG. 5 is a diagram showing an example of NTP data in NTP length format in the IP retransmission system according to the embodiment of the present disclosure.

Referring to FIG. 5, NTP data includes a 32-bit integer field indicating time in seconds and a 32-bit fractional field indicating time in seconds or less.

The conversion unit 25 holds a formula (hereinafter also referred to as a conversion formula) for converting the NTP long format Coordinated Universal Time into the count value of the counter 19A.

The deviation between the time based on the count value of the counter 19A and the Coordinated Universal Time is allowable up to, for example, about 500 nanoseconds. One count of the count value corresponds to about 37 nanoseconds, so even if the count value fluctuates by about 10 counts, it falls within the allowable range.

For example, if the frequency accuracy of the high-precision oscillator 21 is 1 ppm, the count value of the counter 19A is considered to deviate by one count every 37 milliseconds. is calibrated, the time based on the count value can be synchronized with sufficient accuracy to Coordinated Universal Time.

In this example, the conversion unit 25 converts Coordinated Universal Time to the count value of the counter 19A using the conversion formula each time an NTP packet is received from the NTP packet acquisition unit 24, that is, every 33 milliseconds. A count value is set in the counter 19A.

After that, the counter 19A holds a count value obtained by counting 2̂32 Hz clock pulses in the IP retransmission device 101 from the set count value (hereinafter also referred to as a synchronous count value).

As a result, the count value indicated by the counter 19A can represent Coordinated Universal Time with an accuracy of 2̂32 Hz, for example, based on NTP data.

The deletion unit 26 deletes TLV null packets from the stream generated by the tuner 11 .

More specifically, the deletion unit 26 monitors the stream received from the tuner 11 and tries to detect the start code in the TLV header (see FIG. 3).

Upon detecting the start code, the deletion unit 26 checks the value stored in the packet type field after the start code.

When the value stored in the field is 0xFF, the deletion unit 26 determines that the TLV packet containing the start code is a TLV null packet, and deletes the TLV packet from the stream.

On the other hand, when the value stored in the field is a value other than 0xFF, the deletion unit 26 determines that the TLV packet containing the start code is not a TLV null packet, and outputs the TLV packet to the TS conversion unit 27. .

FIG. 6 is a diagram illustrating an example of a TLV packet division method performed in the IP retransmission device according to the embodiment of the present disclosure.

In FIG. 6, "JCTEA STD-002-6.0 Digital Cable Television Broadcast Multiplexing Device", described in Japan CATV Engineering Association (Non-Patent Document 4), TLV packets into multiple TS packets How to store is shown.

7 is a diagram showing an example of the format of the TS packet shown in FIG. 6. FIG.

6 and 7, TS conversion unit 27 creates a plurality of fixed packets each having a predetermined size and including data obtained by dividing TLV packets included in the stream. Here, the TS packet has a size of 188 bytes and is an example of a fixed packet.

More specifically, the TS conversion unit 27 has, for example, a buffer for holding unstored data.

For example, when the TS conversion unit 27 receives the TLV packet 1 (see FIG. 6) from the deletion unit 26 when no unstored data is stored in the buffer, for example, up to 184 bytes from the beginning of the received TLV packet 1 data as divided TLV packets.

The TS conversion unit 27 adds a 3-byte TS header to the obtained divided TLV packet, and if a TLV header exists, adds a 1-byte head TLV instruction, so that the divided TLV packet is stored in the payload. A TS packet (hereinafter referred to as a TLV-stored TS packet) is created, and the created TLV-stored TS packet is output to the TTS conversion unit 28 .

Similarly, the TS conversion unit 27 creates a TLV-stored TS packet and outputs it to the TTS conversion unit 28 every time it acquires 185-byte data from the beginning of the remaining data of the TLV packet 1 as a divided TLV packet.

Also, when the size of the acquired data is less than 185 bytes, the TS conversion unit 27 stores the acquired data in the buffer as unstored data.

Then, when the TS conversion unit 27 receives the subsequent TLV packet 2 (see FIG. 6) from the deletion unit 26, since unstored data is stored in the buffer, the size obtained by subtracting the size of the unstored data from 184 bytes is data from the beginning of TLV packet 2.

The TS conversion unit 27 adds unstored data to the head of the acquired data, arranges the head TLV instruction and the data of TLV packet 2 to create divided TLV packets, and then discards the unstored data in the buffer.

The TS conversion unit 27 adds a TS header to the created divided TLV packet to create a TLV storage TS packet, and outputs the created TLV storage TS packet to the TTS conversion unit 28 .

Although the TS conversion unit 27 is configured to create the TLV-stored TS packets shown in FIGS. 6 and 7, it is not limited to this. If the TS packet has a TS header including a synchronization byte at the beginning and a size of 188 bytes, the TS conversion unit 27 stores the divided TLV packet in a TS packet having the format shown in FIG. 6, for example. may be

In this way, with the configuration using TS packets, it is possible to use the TSoverIP recording device, measuring device, monitoring device, etc. that are used in the MPEG2-TS technical system.

Referring to FIG. 4 again, the TTS conversion unit 28 adds, for example, a time stamp indicating the transmission timing of the TLV-stored TS packet to the TLV-stored TS packet.

More specifically, upon receiving a TLV-stored TS packet from the TS-former 27, the TTS-formatting unit 28 adds a time stamp before the TS header of the TLV-stored TS packet.

Here, the time stamp is an example of processing timing in the content reproducing device, eg IP-STB 171 . For example, IP retransmission device 101 uses the count value of a counter that operates according to the timing of the free-running clock as the processing timing. This processing timing is the processing timing of the TLV-stored TS packet in the IP-STB 171 .

Specifically, the time stamp is the timing at which the IP-STB 171 should input the TLV-stored TS packet to the decoder, for example, the count value of the counter 19B that operates according to the timing of the 27 MHz reference clock in the IP retransmission device 101. . That is, in IP retransmission apparatus 101, the count frequency of the synchronization count value and the count frequency of the time stamp are different. Also, the reference clock is asynchronous among the IP retransmission devices 101 .

By using time stamps, the IP-STB 171 can absorb fluctuations in the transmission time of each IP packet in the network, process TLV-stored TS packets at appropriate timing, and reproduce content information satisfactorily.

Hereinafter, a TLV-stored TS packet to which a time stamp is added is also referred to as a TLV-stored TTS (Time-stamped TS) packet.

The size of the timestamp is a predetermined size, eg 4 bytes. Therefore, the size of a TLV-stored TTS packet is a fixed length of 192 bytes.

The IP conversion unit 17 includes one or more TLV-stored TTS packets received from the TTS conversion unit 28 in an IP packet, and outputs the IP packet to the L3 switch 155 via the switch circuit 20 .

[Theme]
Patent Literature 1 discloses a method of synchronizing the timings of a plurality of delivery devices using TTS packets and PCR.

However, since the broadcast wave of advanced wideband satellite digital broadcasting does not contain PCR, it is necessary to synchronize the timings of multiple distribution devices by another method.

On the other hand, the IP retransmission system according to the embodiment of the present disclosure solves the above problem by the following configuration and operation.

FIG. 8 is a diagram illustrating processing when switching IP retransmission devices by the IP retransmission system according to the embodiment of the present disclosure.

4 and 8, control section 18 in IP retransmitting device 101 can generate timing information regarding processing timing in IP-STB 171 and notify other IP retransmitting devices 101 of it.

For example, the timing information includes the difference Δt between the synchronization count value based on the NTP data and the time stamp Stp_A indicating the processing timing in the IP-STB 171 .

The active IP retransmission device 101 provides the generated timing information to the standby IP retransmission device 101 .

More specifically, when control unit 18 in active IP retransmission device 101 receives, for example, a timing information request from control device 151, which will be described later, control unit 18 sets the current synchronization count value and current time stamp Stp_A to counter 19A and Each of them is acquired from the TTS conversion unit 28, and the difference Δt between the acquired synchronization count value and the time stamp Stp_A is calculated.

Specifically, for example, the control unit 18 acquires the current synchronization count value cnt_A1 from the counter 19A and acquires the current time stamp Stp_A1 from the TTS conversion unit 28 . Then, the control unit 18 calculates the difference Δt1 between the synchronous count value cnt_A1 and the time stamp Stp_A1, and generates timing information including the calculated difference Δt1 and the synchronous count value cnt_A1 from which the difference Δt1 is calculated.

The control unit 18 then transmits the generated timing information to the control device 151 .

Further, for example, when the synchronization count value acquired in response to the timing information request from the control device 151 is synchronization count value cnt_A2, synchronization count value cnt_A3, synchronization count value cnt_A4 or cnt_A5, the control unit 18 outputs the current , and performs the same processing as above.

Control device 151 transmits the timing information received from active IP retransmission device 101 to standby IP retransmission device 101 .

Standby IP retransmission device 101 acquires the timing information generated in active IP retransmission device 101 via control device 151 .

More specifically, the control unit 18 in the standby IP retransmission device 101 acquires the timing information notified from the active IP retransmission device 101 .

Specifically, the control unit 18 receives the timing information transmitted from the control device 151 and acquires the difference Δt1 and the synchronization count value cnt_A1 included in the received timing information.

Based on the difference Δt1 and the synchronization count value cnt_A1 included in the timing information and the synchronization count value based on the synchronization information acquired by itself, the standby IP retransmission device 101 determines the time stamp to be added by itself. Stp_AB is calculated as the processing timing.

More specifically, control unit 18 in standby IP retransmission device 101 uses the acquired synchronization count value cnt_A1 to obtain timing information between active IP retransmission device 101 and standby IP retransmission device 101. The processing timing is calculated by correcting the delay time due to the transmission of .

Here, the active IP retransmitting device 101 and the standby IP retransmitting device 101 synchronize their own counters 19A based on common synchronization information, and each counter 19A uses the same count frequency. Therefore, for example, the synchronous count value cnt_A1 of the counter 19A in the active IP retransmitting device 101 is the same as the synchronous count value cnt_B1 of the counter 19A in the standby IP retransmitting device 101 at the same time.

The control unit 18 in the standby IP retransmission device 101 receives, for example, the timing information transmitted from the control device 151, and counters the current synchronization count value based on the NTP data acquired by its own IP retransmission device 101. 19A.

Specifically, the control unit 18 acquires the synchronous count value cnt_B3, which is the count value of its own counter 19A, from the counter 19A at the timing of receiving the timing information transmitted from the control device 151, for example.

Then, the control unit 18 calculates the delay time Δsec by dividing the value obtained by subtracting the synchronization count value cnt_A1 included in the timing information from the synchronization count value cnt_B3 by 2̂32, which is the count frequency of the synchronization count value. .

Further, the control unit 18 calculates the count increment value of the counter 19A advanced during the delay time Δsec, that is, (1/2̂32)×Δsec. Further, the control unit 18 calculates the count increment value of the counter 19B advanced during the delay time Δsec, that is, (1/27000000)×Δsec.

Then, the control unit 18 calculates a correction value for correcting the delay time Δsec by subtracting the count increment value of the counter 19A from the calculated count increment value of the counter 19B.

The standby IP retransmitting device 101 transmits an IP packet containing the processing timing based on the timing information given from the active IP retransmitting device 101 .

More specifically, control unit 18 corrects the count value of counter 19B, for example, using the calculated correction value and the acquired difference Δt1 in active IP retransmission device 101 . Specifically, the control unit 18 sets a value obtained by adding the difference Δt1 and the calculated correction value to the synchronization count value cnt_B3 (hereinafter also referred to as time stamp Stp_AB1) in the counter 19B.

After that, the counter 19B holds a count value obtained by counting the pulses of the 27 MHz reference clock in its own IP retransmission device 101 from the set time stamp Stp_AB1. That is, in standby IP retransmission apparatus 101, the count value of counter 19B is corrected from the original count value (hereinafter also referred to as time stamp Stp_B) to time stamp Stp_AB.

For example, by using the count value of the counter 19B based on the time stamp Stp_AB1, the TTS unit 28 matches the time stamp in the active IP retransmitting device 101 with the time stamp in the standby IP retransmitting device 101. can be done.

Then, the TTS unit 28 generates and transmits an IP packet including processing timing based on the timing information acquired by the control unit 18 .

More specifically, the TTS conversion unit 28 creates TLV storage TTS to which the corrected time stamp, ie, the count value of the counter 19B is added, and outputs the created TLV storage TTS to the IP conversion unit 17 .

The IP conversion unit 17 includes one or more TLV-stored TTS packets received from the TTS conversion unit 28 in an IP packet, and outputs the IP packet to the L3 switch 155 via the switch circuit 20 .

[Flow of operation]
Next, the flow of switching operation of the IP retransmission device in the IP retransmission system according to the embodiment of the present disclosure will be described.

Each device in the IP retransmission system 301 has a computer including a memory, and an arithmetic processing unit such as a CPU in the computer reads and executes a program including part or all of each step in the following flowchart from the memory. do. Programs for these multiple devices can each be installed from the outside. Programs for these devices are stored in recording media and distributed.

FIG. 9 is a diagram illustrating an example of a sequence of switching processing of IP retransmission devices by the IP retransmission system according to the embodiment of the present disclosure.

Referring to FIG. 9, in a situation where IP retransmitting device 101A and IP retransmitting device 101B, which are IP retransmitting devices 101, are active and standby, respectively, first, control device 151 controls IP retransmitting device 101A. An error is detected (step S1), and a standby instruction is transmitted to the IP retransmission device 101A (step S2).

IP retransmitting device 101A receives the standby instruction from control device 151, stops transmission of IP packets, SI information, and emergency alerts by, for example, turning off switch circuit 20, and becomes a standby system (step S3).

Next, control device 151 transmits an operation instruction to IP retransmission device 101B (step S4).

Next, IP retransmitting device 101B receives an operation instruction from control device 151, and matches the frequency of the received broadcast wave to the frequency of the broadcast wave received by IP retransmitting device 101A. IP retransmission device 101B then turns on switch circuit 20, for example, to start transmission of IP packets, SI information, and emergency alerts, and becomes an active system (step S5).

Next, when the replacement or repair of the IP retransmission device 101A is completed, the control device 151 accepts a switching instruction by an operator's operation, for example (step S6).

Next, the control device 151 transmits a timing information request to the IP retransmission device 101B (step S7).

Next, IP retransmitting device 101B receives the timing information request from control device 151, generates timing information including the latest synchronization count value of itself and the difference Δt corresponding to the synchronization count value, and 151 (step S8).

Next, the control device 151 transmits the timing information received from the IP retransmission device 101B to the IP retransmission device 101A (step S9).

Next, the standby IP retransmitting device 101A acquires, via the control device 151, information about the processing timing in the IP-STB 171 generated in the active IP retransmitting device 101B. More specifically, IP retransmitting device 101A receives the timing information from control device 151, and calculates the synchronization count value of IP retransmitting device 101B included in the received timing information and the difference Δt corresponding to the synchronization count value. acquire (step S10).

Next, the standby IP retransmission device 101A calculates the processing timing to be added by itself based on the acquired synchronization count value and the difference Δt of the IP retransmission device 101B and the acquired own synchronization count value. (step S11).

Next, the standby IP retransmission device 101A performs adjustment processing based on the calculated processing timing, for example, corrects the count value of the counter 19B as described above (step S12), and transmits ACK to the control device 151. (Step S13).

Next, the control device 151 switches content retransmission from the active IP retransmission device 101B to the standby IP retransmission device 101A. More specifically, as switching of content retransmission, control device 151 causes active IP retransmission device 101B to stop retransmission of content at a predetermined switching timing, and causes standby IP retransmission device 101A to stop retransmission of content at a predetermined switching timing. retransmission of the content is started at the switching timing of . That is, control device 151 receives ACK from IP retransmitting device 101A and notifies IP retransmitting device 101A and IP retransmitting device 101B of predetermined switching timing.

Specifically, control device 151 notifies IP retransmission device 101A and IP retransmission device 101B of a time stamp indicating the switching timing. Here, when the control device 151 needs to adjust the timing between the transmission stop timing of the IP retransmission device 101A and the transmission start timing of the IP retransmission device 101B, the control device 151 sets the time stamp to be transmitted to each IP retransmission device 101. It may be adjusted to notify a different timestamp. That is, the switching timing may differ between the active IP retransmitting device 101 and the standby IP retransmitting device 101 (steps S14 and S16).

Next, IP retransmitting device 101A and IP retransmitting device 101B, upon receiving notification of the time stamp from control device 151, transmit ACK to control device 151 (steps S15 and S17).

Next, at a predetermined timing, ie, the timing of the time stamp notified from control device 151, IP retransmission device 101B stops transmitting IP packets, SI information, and emergency alerts, and becomes a standby system (step S18).

At a predetermined timing, that is, at the timing of the time stamp notified from control device 151, IP retransmitting device 101A starts transmitting IP packets, SI information, and emergency alerts, and becomes an active system. That is, the IP retransmitting device 101A transmits an IP packet containing the processing timing based on the timing information given from the control device 151 . More specifically, the IP retransmitting device 101A transmits the TTS packet including the processing timing calculated based on the timing information given from the control device 151 (step S19).

FIG. 10 is a diagram showing the configuration of a control device in the IP retransmission system according to the embodiment of the present disclosure.

Referring to FIG. 10 , control device 151 includes broadcast wave instruction section 31 , acquisition section 32 , information addition section 33 , and switching instruction section 34 .

Broadcast wave command unit 31 instructs standby IP retransmitting device 101 to match the frequency of the received broadcast wave with the frequency of the broadcast wave received by active IP retransmitting device 101. Notify operational instructions.

Acquisition unit 32 transmits the above-described timing information request, for example, to generate a synchronization count value that can be acquired by each IP retransmission device 101 and a content reproduction device, such as Timing information including a time stamp indicating the processing timing in the IP-STB 171, that is, the difference Δt from the count value of the counter 19B is obtained.

The information providing unit 33 provides the timing information acquired by the acquiring unit 32 to the standby IP retransmission device 101 . More specifically, information adding section 33 gives the timing information generated in active IP retransmitting device 101 to standby IP retransmitting device 101 .

The switching instruction unit 34 issues an instruction for the active IP retransmitting device 101 to stop retransmitting content at a predetermined timing and for the standby IP retransmitting device 101 to start retransmitting content at a predetermined timing. Notify the switching timing described above. The predetermined timing is, for example, the timing specified using the processing timing as described above.

[Modification]
FIG. 11 is a diagram showing a configuration of a modification of the IP retransmission device in the IP retransmission system according to the embodiment of the present disclosure.

Referring to FIG. 11, IP retransmitting apparatus 102 is different from IP retransmitting apparatus 101 shown in FIG. A packet including NTP data periodically or irregularly transmitted by an external NTP server 156 is obtained.

More specifically, NTP packet acquisition unit 24 receives the packet transmitted from NTP server 156 periodically or irregularly via, for example, a network, and outputs the received packet to conversion unit 25 .

The conversion unit 25 acquires Coordinated Universal Time in NTP length format from the NTP data included in the packet received from the NTP packet acquisition unit 24 . Then, the conversion unit 25 uses the acquired Coordinated Universal Time to set the time for the counter 19A.

In addition, although the IP retransmission system according to the embodiment of the present disclosure has a configuration in which the count frequency of the synchronization count value and the count frequency of the time stamp are different, the configuration is not limited to this. In the IP retransmission system 301, the count frequency of the synchronization count value and the count frequency of the time stamp may be the same frequency.

Moreover, although the IP retransmission system according to the embodiment of the present disclosure is configured to use broadcast waves such as advanced wideband satellite digital broadcasting, the present invention is not limited to this. IP retransmission system 301 may be configured to use broadcast waves other than advanced broadband satellite digital broadcasts including NTP data as synchronization information.

Also, in the IP retransmission system according to the embodiment of the present invention, the IP retransmission apparatus 101 is configured to include the TLV-stored TTS packet in the IP packet and transmit it, but the configuration is not limited to this. In the IP retransmission system 301, the IP retransmission device 101 may be configured to include, in an IP packet, a packet that is a different type of packet from the TLV-stored TTS packet and to which a time stamp has been added.

By the way, in a broadcasting system in which a plurality of active and standby distribution devices are provided, the distribution device may transmit information on the timing at which the packet should be processed in the packet. It is difficult to stop the broadcast output when, for example, a 24-hour broadcast is performed in a situation where an active distribution apparatus is to be replaced for maintenance. For this reason, it is necessary to stop the output of the distribution device and switch the distribution to the standby distribution device for maintenance and replacement of the active distribution device. , it becomes difficult to reproduce the content satisfactorily.

In contrast, in the IP retransmission system according to the embodiment of the present disclosure, a plurality of IP retransmission devices 101 receive broadcast waves, include content included in the broadcast waves in IP packets, and retransmit the IP packets. The switching method according to the embodiment of the present disclosure is a switching method for switching retransmission of content from active IP retransmitting device 101 to standby IP retransmitting device 101 . First, the frequency of the broadcast wave received by the IP retransmission device 101 of the standby system is adjusted to the frequency of the broadcast wave received by the IP retransmission device 101 of the active system. Next, the synchronization count value based on the synchronization information for time synchronization that can be acquired by each IP retransmission device 101, which is information generated in the active IP retransmission device 101, and the processing timing in the content reproduction device are calculated. Timing information including the difference Δt from the indicated time stamp is provided to the standby IP retransmission device 101 . Next, at a predetermined timing, the retransmission of content is switched from the IP retransmission device 101 of the active system to the IP retransmission device 101 of the standby system. Next, IP retransmitting device 101 of the switching destination includes the processing timing based on the given timing information in the IP packet and transmits it.

With this method, compared to the case where the output stop timing of the active IP retransmitting device 101 and the output start timing of the standby IP retransmitting device 101 are simply switched together, the playback device can It is possible to stably process the IP packets transmitted from the IP retransmitting device 101 and reproduce the content satisfactorily. In addition, by using the synchronization information that can be acquired by each IP retransmitting device 101, it is possible to avoid the influence of delay in transmission of timing information from the active IP retransmitting device 101 to the standby IP retransmitting device. .

Therefore, with the switching method according to the embodiment of the present disclosure, it is possible to realize stable content reproduction in the reproduction device in a configuration that allows switching of the content transmission device.

Also, in the switching method according to the embodiment of the present disclosure, the count frequency of the synchronization count value and the count frequency of the time stamp are different. The timing information further includes a synchronization count value from which the difference Δt is calculated. In the switching method according to the embodiment of the present disclosure, IP retransmission device 101 to which switching is performed further uses difference Δt and synchronization count value included in the timing information and the count value based on the synchronization information acquired by itself. to calculate the processing timing.

With this method, in a system with different synchronization count values and timestamp frequencies, it is possible to easily match the timing of the timestamp in the active IP retransmitting device 101 and the timestamp in the standby IP retransmitting device. .

Also, in the switching method according to the embodiment of the present disclosure, the synchronization information is NTP data included in broadcast waves. The processing timing is a time stamp included in the TLV storage TTS.

By such a method, in a system that performs an IP retransmission service for transmitting advanced broadband satellite digital broadcasting to a subscriber's home via the IP network 401, NTP data can be effectively used, and the switching destination IP retransmission device 101 can be used. It is possible to stably process the IP packets transmitted from and reproduce the content satisfactorily.

In addition, in the IP retransmission system according to the embodiment of the present disclosure, the plurality of IP retransmission devices 101 receive the same broadcast wave from the distributor 152, include the content included in the broadcast wave in the IP packet, and reproduce the content. Send. The L3 switch 155 relays IP packets output from each IP retransmission device 101 and transmits them to the network. Standby IP retransmitting device 101 adjusts the frequency of the received broadcast wave to the frequency of the broadcast wave received by active IP retransmitting device 101 . The standby IP retransmission device 101 generates a synchronization count value based on synchronization information for time synchronization that can be acquired in each IP retransmission device 101, which is information generated in the active IP retransmission device 101, and a content timing information including the difference Δt from the time stamp indicating the processing timing in the playback device is obtained via the control device 151 . Control device 151 causes active IP retransmitting device 101 to stop retransmitting content at a predetermined timing, and causes standby IP retransmitting device 101 to stop retransmitting content at a predetermined timing. Transmission is started, and IP retransmission device 101 of the switching destination transmits an IP packet including processing timing based on the given timing information.

With such a configuration, compared to the case where the output stop timing of the active IP retransmitting device 101 and the output start timing of the standby IP retransmitting device 101 are simply switched, It is possible to stably process the IP packets transmitted from the IP retransmitting device 101 and reproduce the content satisfactorily. In addition, by using the synchronization information that can be acquired by each IP retransmitting device 101, it is possible to avoid the influence of delay in transmission of timing information from the active IP retransmitting device 101 to the standby IP retransmitting device. .

Therefore, in the IP retransmission system according to the embodiment of the present disclosure, it is possible to realize stable content reproduction in the reproduction device in a configuration that allows switching of the content transmission device.

Further, in the IP retransmission device according to the embodiment of the present disclosure, the control unit 18 controls the synchronization count value based on the synchronization information for time synchronization that can be acquired in each IP retransmission device 101, and the processing in the content reproduction device. Timing information including a difference Δt from a time stamp indicating timing is generated. The control unit 18 notifies the other IP retransmission device 101 of the generated timing information. The control unit 18 acquires the timing information notified from the other IP retransmission device 101 . The packet processing unit 22 generates and transmits an IP packet including processing timing based on the timing information acquired by the control unit 18 .

With such a configuration, compared to the case where the output stop timing of the active IP retransmitting device 101 and the output start timing of the standby IP retransmitting device 101 are simply switched, It is possible to stably process the IP packets transmitted from the IP retransmitting device 101 and reproduce the content satisfactorily. In addition, by using the synchronization information that can be acquired by each IP retransmitting device 101, it is possible to avoid the influence of delay in transmission of timing information from the active IP retransmitting device 101 to the standby IP retransmitting device. .

Therefore, with the IP retransmission device according to the embodiment of the present disclosure, it is possible to realize stable content reproduction in the reproduction device in a configuration in which the content transmission device can be switched.

Further, in the control device according to the embodiment of the present disclosure, broadcast wave command unit 31 instructs standby IP retransmission device 101 to set the frequency of the broadcast wave to be received by active IP retransmission device 101 to It notifies an operation instruction to match the frequency of the received broadcast wave. The acquisition unit 32 acquires a synchronization count value based on synchronization information for time synchronization that can be acquired by each IP retransmission device 101, which is information generated by the active IP retransmission device 101, and processing in the content reproduction device. Timing information including a difference Δt from a time stamp indicating timing is acquired. The information providing unit 33 provides the timing information acquired by the acquiring unit 32 to the standby IP retransmission device 101 . The switching command unit 34 commands the active IP retransmitting device 101 to stop retransmitting content at a predetermined timing and the standby IP retransmitting device 101 to start retransmitting content at a predetermined timing. Notice.

With such a configuration, compared to the case where the output stop timing of the active IP retransmitting device 101 and the output start timing of the standby IP retransmitting device 101 are simply switched, It is possible to stably process the IP packets transmitted from the IP retransmitting device 101 and reproduce the content satisfactorily. In addition, by using the synchronization information that can be acquired by each IP retransmitting device 101, it is possible to avoid the influence of delay in transmission of timing information from the active IP retransmitting device 101 to the standby IP retransmitting device. .

Therefore, in the control device according to the embodiment of the present disclosure, it is possible to realize stable content reproduction in the reproduction device in a configuration that allows switching of the content transmission device.

The above-described embodiments should be considered as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

The above description includes features appended below.
[Appendix 1]
a plurality of IP retransmitting devices that receive the same broadcast wave from a distributor and retransmit IP packets containing content included in the broadcast wave;
a control device;
the IP packet output from each IP retransmission device is relayed by a relay device and transmitted to a network;
the standby IP retransmission device adjusts the frequency of the received broadcast wave to the frequency of the broadcast wave received by the active IP retransmission device;
The standby IP retransmission device has a first count value based on synchronization information for time synchronization that can be acquired by each of the IP retransmission devices, which is information generated in the active IP retransmission device. obtaining, via the control device, timing information including a difference from a second count value indicating processing timing in the content reproduction device;
The control device causes the active IP retransmission device to stop retransmission of the content at a predetermined timing, and causes the standby IP retransmission device to stop retransmission of the content at a predetermined timing, as switching of retransmission of the content. initiate a resend of the content,
the IP retransmission device to be switched to transmits the IP packet including the processing timing based on the given timing information;
the second count value is a count value of a counter that operates according to timing of a clock generated by a high-precision oscillator in the IP retransmission device;
The standby IP retransmission device corrects the second count value based on the acquired timing information,
The IP retransmitting device includes a plurality of TS packets containing information obtained by dividing the content into a plurality of pieces in one or more of the IP packets and retransmits them,
The IP retransmission system, wherein the processing timing is the processing timing of the TS packet in the playback device.

[Appendix 2]
An IP retransmission device in an IP retransmission system that receives a broadcast wave, includes content included in the broadcast wave in an IP packet, and retransmits the content,
generating timing information including a difference between a first count value based on synchronization information for time synchronization that can be acquired in each IP retransmission device and a second count value indicating processing timing in the content reproduction device; a timing information generator;
a notification unit that notifies the other IP retransmission device of the timing information generated by the timing information generation unit;
an acquisition unit that acquires the timing information notified from the other IP retransmission device;
a packet processing unit that generates and transmits the IP packet including the processing timing based on the timing information acquired by the acquisition unit;
the second count value is a count value of a counter that operates according to timing of a clock generated by a high-precision oscillator in the IP retransmission device;
The packet processing unit corrects the second count value based on the acquired timing information,
The packet processing unit includes a plurality of TS packets containing information obtained by dividing the content into a plurality of pieces in one or more of the IP packets and retransmits them,
The IP retransmission device, wherein the processing timing is the processing timing of the TS packet in the playback device.

[Appendix 3]
A control device in an IP retransmission system comprising a plurality of IP retransmission devices that receive broadcast waves and retransmit IP packets containing content included in the broadcast waves,
a broadcast wave command unit that notifies the IP retransmission device of the standby system of a command to match the frequency of the broadcast wave to be received with the frequency of the broadcast wave received by the IP retransmission device of the active system;
A first count value based on synchronization information for time synchronization that can be acquired in each IP retransmission device, which is information generated in the active IP retransmission device, and a processing timing in the content reproduction device. an acquisition unit that acquires timing information including a difference from the second count value indicated;
an information addition unit that provides the timing information acquired by the acquisition unit to the standby IP retransmission device;
A switching command for notifying an order for the active IP retransmission device to stop retransmission of the content at a predetermined timing and for the standby IP retransmission device to start retransmission of the content at a predetermined timing. and
the second count value is a count value of a counter that operates according to timing of a clock generated by a high-precision oscillator in the IP retransmission device;
The standby IP retransmission device corrects the second count value based on the timing information provided by the information addition unit,
The IP retransmitting device includes a plurality of TS packets containing information obtained by dividing the content into a plurality of pieces in one or more of the IP packets and retransmits them,
The control device, wherein the processing timing is the processing timing of the TS packet in the playback device.

11 tuner 17 IP conversion unit 18 control unit (timing information generation unit, notification unit and acquisition unit)
19A, 19B counter 20 switch circuit 21 high accuracy oscillator 22 packet processing unit 23 multiplier circuit 24 NTP packet acquisition unit 25 conversion unit 26 deletion unit 27 TS conversion unit 28 TTS conversion unit 31 broadcast wave command unit 32 acquisition unit 33 information addition unit 34 Switching instruction unit 81 antenna 101, 102 IP retransmission device 151 control device 152 distributor 153 L2 switch 155 L3 switch 156 NTP server 161 all-station SI server 162 emergency alert server 301 IP retransmission system 401 IP network 171 IP-STB
172 TV
301 IP retransmission system

Claims (6)

In an IP retransmission system comprising a plurality of IP retransmission devices that receive broadcast waves and retransmit IP packets containing content included in the broadcast waves, the retransmission of the content is performed by the active IP retransmission device. A switching method for switching from a standby system to the IP retransmission device,
a step of matching the frequency of the broadcast wave received by the standby IP retransmission device to the frequency of the broadcast wave received by the active IP retransmission device;
A first count value based on synchronization information for time synchronization that can be acquired in each IP retransmission device, which is information generated in the active IP retransmission device, and a processing timing in the content reproduction device. providing timing information including a difference from the indicated second count value to the standby IP retransmission device;
switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device at a predetermined timing;
a switching method, wherein the standby IP retransmission device includes the processing timing based on the given timing information in the IP packet and transmits the IP packet. The count frequency of the first count value and the count frequency of the second count value are different,
the timing information further includes the first count value from which the difference is calculated;
The switching method further comprises:
The standby IP retransmission device calculates the processing timing based on the difference and the first count value included in the timing information and the count value based on the synchronization information acquired by itself. 2. The switching method of claim 1, comprising the steps of: The synchronization information is NTP (Network Time Protocol) data included in the broadcast wave,
3. The switching method according to claim 1, wherein said processing timing is a time stamp included in a TTS (Time-stamped TS) packet. a plurality of IP retransmitting devices that receive the same broadcast wave from a distributor and retransmit IP packets containing content included in the broadcast wave;
a control device;
the IP packet output from each IP retransmission device is relayed by a relay device and transmitted to a network;
the standby IP retransmission device adjusts the frequency of the received broadcast wave to the frequency of the broadcast wave received by the active IP retransmission device;
The standby IP retransmission device has a first count value based on synchronization information for time synchronization that can be acquired by each of the IP retransmission devices, which is information generated in the active IP retransmission device. obtaining, via the control device, timing information including a difference from a second count value indicating processing timing in the content reproduction device;
The control device causes the active IP retransmission device to stop retransmission of the content at a predetermined timing, and causes the standby IP retransmission device to stop retransmission of the content at a predetermined timing, as switching of retransmission of the content. initiate a resend of the content,
The IP retransmission system, wherein the standby IP retransmission device transmits the IP packet including the processing timing based on the given timing information. An IP retransmission device in an IP retransmission system that receives a broadcast wave, includes content included in the broadcast wave in an IP packet, and retransmits the content,
generating timing information including a difference between a first count value based on synchronization information for time synchronization that can be acquired in each IP retransmission device and a second count value indicating processing timing in the content reproduction device; a timing information generator;
a notification unit that notifies the other IP retransmission device of the timing information generated by the timing information generation unit;
an acquisition unit that acquires the timing information notified from the other IP retransmission device;
and a packet processing unit that generates and transmits the IP packet including the processing timing based on the timing information acquired by the acquisition unit. A control device in an IP retransmission system comprising a plurality of IP retransmission devices that receive broadcast waves and retransmit IP packets containing content included in the broadcast waves,
a broadcast wave command unit that notifies the IP retransmission device of the standby system of a command to match the frequency of the broadcast wave to be received with the frequency of the broadcast wave received by the IP retransmission device of the active system;
A first count value based on synchronization information for time synchronization that can be acquired in each IP retransmission device, which is information generated in the active IP retransmission device, and a processing timing in the content reproduction device. an acquisition unit that acquires timing information including a difference from the second count value indicated;
an information addition unit that provides the timing information acquired by the acquisition unit to the standby IP retransmission device;
A switching command for notifying an order for the active IP retransmission device to stop retransmission of the content at a predetermined timing and for the standby IP retransmission device to start retransmission of the content at a predetermined timing. A controller, comprising:

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