JP2018125742A - Multiplexer, switching device, transmission system, and transmission method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to identify a switching point of TLV packets between a main system and a redundant system and achieve seamless switching not requiring analysis of video data and voice data.SOLUTION: According to embodiments, a multiplexer detects an MMTP packet corresponding to a switching point between a main system and a redundant system from MMTP packets to be converted into TLV packets, converts the MMTP packet into TLV packets, and generates a TLV packet corresponding to the detected switching point. The switching device detects input TLV packets, identifies the TLV packet corresponding to the switching point from the detected TLV packets, and executes switching between the main system and the redundant system at the identified TLV packet.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a multiplexing device, a switching device, a transmission system, and a transmission method for a hybrid content distribution service that links broadcasting and communication.

  Conventionally, an MMT (MPEG Media Transport) system has been adopted as a data multiplexing system for 4K and 8K broadcasting as a new multiplexing system for realizing a hybrid content distribution service that links broadcasting and communication. In a transmission system that employs the MMT method, a redundant configuration including two or more systems may be assembled so that the function can be maintained even when a failure occurs. If a failure occurs in the main system or maintenance is required, switching from the main system to the redundant system is performed by the switching device. Therefore, such a switching device is desired to seamlessly switch between the main system and the redundant system as much as possible. Non-Patent Document 1 describes “MMT Operation Guidelines at Redundant System Switching” as a specific operation rule.

  The “MMT operation guideline for redundant system switching” describes the transmission side guideline and the reception side guideline. Specifically, the transmission side guideline includes the following description.

(Guideline T1.1)
The redundant transmission system should match the GOP (Group of Pictures) phase with the main transmission system as much as possible. In addition, system switching should be performed in consideration of matching with pointer slot information transmitted two frames ahead of the main line signal.
Switching in consideration of the consistency of the relationship between MPU (Media Processing Unit) time stamp and MPU.

(Guideline T1.2)
If the processing contents change, to prevent the version number from changing due to redundancy switching, further change the version number on the sending side.

(Guideline T1.3)
System switching should be performed with audio muted as much as possible.

  When the main system and the redundant system are seamlessly switched in accordance with such a transmission side guideline, a process for aligning the GOP phases of the main system and the redundant system is performed by the encoding device, and a switching point is created in the video data and the audio data. Is done.

  Accordingly, the switching point is identified by the switching device, and the system switching from the main system to the redundant system is performed at the switching point.

ARIB TR-B39 Chapter 7 Chapter 5 5.6 Guidelines for MMT Operation when Switching Redundant Systems

  However, such conventional methods have the following problems.

  That is, since the transmission format of the TLV packet cannot add information indicating the switching point, the switching device needs to analyze video data, audio data, and the like included in the TLV packet, which places a burden on analysis processing. There is a problem.

  The problem to be solved by the present invention is to provide a multiplexing device that makes it possible to identify a switching point of a TLV packet between a main system and a redundant system. Further, this provides a switching device, a transmission system, and a transmission method that can seamlessly switch TLV packets between the main system and the redundant system without analyzing video data, audio data, and the like. is there.

  The transmission system of the embodiment is a transmission system including a main system and a redundant system for transmitting a TLV packet, and includes a multiplexing device provided in each of the main system and the redundant system, and a main system and a redundant system. And a switching device for switching between the systems. The multiplexing apparatus includes a first detection unit that detects an MMTP packet corresponding to a switching point between the primary system and the redundant system from an MMTP (MPEG Media Transport Protocol) packet that is converted into a TLV packet, and the MMTP packet is converted into a TLV packet. And a generating unit that generates a TLV packet corresponding to the switching point detected by the first detecting unit. The switching device includes: a second detection unit that detects an input TLV packet; an identification unit that identifies a TLV packet corresponding to a switching point from the TLV packet detected by the second detection unit; and the identified TLV The packet includes a switching unit that switches between the main system and the redundant system.

It is a block diagram which shows the example of whole structure of the transmission system with which the transmission method of embodiment of this invention was applied. It is a block diagram which shows the structural example of an encoding apparatus. It is a figure which shows the structure of the MMTP packet defined by ARIB STD-B60. It is a figure which shows the structure (ARIB STD-B60) of a MMTP payload. It is a block diagram which shows the structural example of a TLV multiplexing apparatus. It is a figure which shows the structure of the TLV packet prescribed | regulated by ARIB STD-B32. It is a figure which shows allocation of the "packet type" in the TLV packet prescribed | regulated by ARIB STD-B32. It is a block diagram which shows the structural example of a redundant switching apparatus. It is a flowchart (1/3) which shows the operation example of the transmission system to which the transmission method of embodiment of this invention was applied. It is a flowchart (2/3) which shows the operation example of the transmission system to which the transmission method of embodiment of this invention was applied. It is a flowchart (3/3) which shows the operation example of the transmission system to which the transmission method of embodiment of this invention was applied.

  A transmission system to which a transmission method according to an embodiment of the present invention is applied will be described below with reference to the drawings.

(Overall configuration of transmission system)
FIG. 1 is a block diagram illustrating an overall configuration example of a TLV packet transmission system 10 that transmits a TLV packet as an example of a transmission system to which a transmission method according to an embodiment of the present invention is applied.

  The TLV packet transmission system 10 according to the embodiment of the present invention includes two systems of a main system and a redundant system in order to transmit a TLV packet that is an example of a broadcast signal. The TLV packet transmission system 10 includes a field-programmable gate array (FPGA), a central processing unit (CPU) or a combination thereof, and a program memory (for example, a solid state drive (SSD) and a hard disk drive (HDD)) that constitute a computer. As a control function necessary for carrying out the present embodiment, a coding device 20 (# 1) and an MMT multiplexing device 30 (# 1) are provided as main systems. ), A scrambler 50 (# 1), an IP multiplexer 60 (# 1), and a TLV multiplexer 70 (# 1). As a redundant system, an encoder 20 (# 2) and an MMT multiplexer 30 are provided. (# 2), scrambler 50 (# 2), IP multiplexer 60 (# 2), and TLV multiplexer 70 (# 2). And a common redundant switching device 90 and a redundancy system. All of these control functions are realized by causing the FPGA or CPU to execute a program stored in the program memory.

  In addition, the TLV is configured so that external inputs are made to the encoding devices 20 (# 1), 20 (# 2), the TLV multiplexing devices 70 (# 1), 70 (# 2), and the redundancy switching device 90. An external input device 100 is connected to the packet transmission system 10.

(Encoding device)
FIG. 2 is a block diagram illustrating a configuration example of the encoding device 20.

  The encoding devices 20 (# 1) and 20 (# 2), for example, convert a video signal, an audio signal, and a caption signal input from a broadcast master system (not shown) into a broadcast signal in an MMTP (MPEG Media Transport Protocol) packet format. This is a device for conversion, and includes a switching control receiving unit 21, a GOP phase adjusting unit 22, a signal encoding unit 23, a switching information setting unit 24, and an MMTP packetizing unit 25. Since both the encoding devices 20 (# 1) and 20 (# 2) have the same configuration, the above-described components will be described below without distinguishing between the main system and the redundant system.

  The signal encoding unit 23 receives, for example, a video signal, an audio signal, and a caption signal input from a broadcast master system (not shown), encodes (compresses) the received signals, and encodes (compresses) them. The video signal, the audio signal, and the caption signal are output to the switching information setting unit 24 and the MMTP packetizing unit 25, respectively.

  The switching control receiving unit 21 receives a request for switching between the main system and the redundant system from the external input device 100. When the switching control accepting unit 21 receives a switching request, the GOP phase adjusting unit 22, the switching information setting unit 24, and the MMTP packetizing unit 25 perform the main system and the redundant system as described below. The process for switching is executed.

  The GOP phase adjustment unit 22 outputs an adjustment signal for aligning the GOP (Group of Pictures) phases of the video signal, the audio signal, and the caption signal to the switching information setting unit 24 after receiving the request by the switching control receiving unit 21. To do.

  The switching information setting unit 24 sets a predetermined value (for example, 0) to an MPU (Media Processing Unit) sequence number included in the MMTP packet corresponding to the switching point between the main system and the redundant system determined based on the adjustment signal. Generate an instruction input to set Then, this instruction input is output to the MMTP packetization unit 25.

  Alternatively, the switching information setting unit 24 sets the least significant bit of the time stamp field included in the MMTP packet corresponding to the switching point between the main system and the redundant system determined based on the adjustment signal to a predetermined value (for example, 0 ) To generate an instruction input. Then, this instruction input is output to the MMTP packetization unit 25.

  FIG. 3 is a diagram showing a configuration of an MMTP packet defined in ARIB STD-B60, which is a standard of ARIB (Radio Industry Association). Further, FIG. 4 is a diagram showing a configuration of the MMTP payload (ARIB STD-B60) indicated by a box at the end of the data structure of FIG. MPU_sequence_number indicated by a box in FIG. 4 is an MPU sequence number.

  The MMTP packetizing unit 25 packetizes the video signal, the audio signal, and the caption signal encoded (compressed) by the signal encoding unit 23 to generate respective MMTP packets.

  In this way, the MMTP packetizing unit 25 outputs the MMTP packets of the video signal, the audio signal, and the caption signal to the MMT multiplexing apparatus 30 in a state where the switching point can be identified.

  Note that the video master signal, the audio signal, and the caption signal are not always input from the broadcast master system to the encoding device 20, and only one or two of these signals are input. There may be cases. For example, when only the video signal is input from the broadcast master system to the encoding device 20, the encoding device 20 outputs only the MMTP packet of the video signal to the MMT multiplexing device 30. When the video signal and the audio signal are input from the broadcast master system to the encoding device 20, the encoding device 20 outputs the MMTP packet of the video signal and the MMTP packet of the audio signal to the MMT multiplexing device 30. That's it.

(MMT multiplexer)
Both the MMT multiplexing devices 30 (# 1) and 30 (# 2) have the same configuration, and the MMTP packets output by the corresponding encoding devices 20 (# 1) and 20 (# 2) ( For example, MMTP packets for video signals, MMTP packets for audio signals, and MMTP packets for subtitles) and data in the MMTP packet format output from an EPG (electronic program guide) sending device (not shown) are multiplexed and multiplexed. The MMTP packet is output to the scrambler 50 of the same system. In addition, the MMT multiplexers 30 (# 1) and 30 (# 2) also internally generate (reconstruct) MMT-SI such as PA messages as necessary.

(Scrambler)
The scramblers 50 (# 1) and 50 (# 2) have the same configuration, and the MMTP packets output from the corresponding MMT multiplexers 30 (# 1) and 30 (# 2) Then, encryption for copyright protection is performed, and the encrypted MMTP packet is output to the IP multiplexer 60 of the same system. Since encryption is not essential, the scrambler 50 may not be provided.

  The IP multiplexers 60 (# 1) and 60 (# 2) have the same configuration, and the MMTP packets output from the corresponding scramblers 50 (# 1) and 50 (# 2) are received. The data is multiplexed with IP packet format data from another device (not shown). Then, the MMTP packet and the IP packet obtained as a result of multiplexing are output to the TLV multiplexing device 70 of the same system.

(TLV multiplexer)
FIG. 5 is a block diagram illustrating a configuration example of the TLV multiplexing device 70. The TLV multiplexer 70 detects the MMTP packet corresponding to the switching point between the primary system and the redundant system from the MMTP packets output from the IP multiplexer 60 of the same system, and converts the MMTP packet into a TLV packet. A device for generating a TLV packet corresponding to the detected switching point. Hereinafter, the configuration of such a TLV multiplexer 70 will be described.

  The TLV multiplexers 70 (# 1) and 70 (# 2) have the same configuration, and the MMTP packet / IP packet (for example, the MMTP of the video signal) output from the IP multiplexer 60 of the same system. Packet / IP packet, voice signal MMTP packet / IP packet, subtitle MMTP packet / IP packet, etc., which are encrypted when the scrambler 50 is provided) The TLV transmission format (TLV packet) is converted, and the TLV packet obtained by the conversion is output to the redundancy switching device 90. In addition, TLV-SI is generated internally.

  In order to realize this, the TLV multiplexer 70 includes a receiving unit 71, a filter unit 72, a sequence number acquisition unit 73, a switching point detection unit 74, and a switching point detection unit 74 provided for each type of input MMTP packet / IP packet. A TLV packetization unit 77 is provided. In addition, one switching control reception unit 75, one multiplexing unit 76, one TLV-SI generation unit 78, one null packet generation unit 79, and one transmission unit 81 are provided.

  The receiving units 71 (# 1),..., 71 (#n) are provided for each type of MMTP packet / IP packet input to the TLV multiplexer 70. For example, the receiving unit 71 (# 1) ) Receives the MMTP packet / IP packet of the video signal output from the IP multiplexer 60, and the receiving unit 71 (# 2) receives the MMTP packet / IP packet of the audio signal output from the encoder 20. The unit 71 (#n) receives the MMTP packet / IP packet of the electronic program guide output from the EPG (not shown), and outputs it to the corresponding filter unit 72.

  The filter units 72 (# 1),..., 72 (#n) are provided corresponding to the receiving units 71 (# 1),..., 71 (#n), respectively. 72 (# 1) performs a filtering process on the MMTP packet / IP packet of the video signal output from the receiving unit 71 (# 1), and the filtering unit 72 (# 2) receives the receiving unit 71 (# 2). Filtering is performed on the MMTP packet / IP packet of the audio signal output from the filter unit 72 (#n), and the MMTP packet / IP packet of the electronic program guide output from the receiving unit 71 (#n) Filter processing is performed on the image. Then, the filtered MMTP packet / IP packet is output to the corresponding sequence number acquisition unit 73.

  Sequence number acquisition units 73 (# 1),..., 73 (#n) are provided corresponding to the filter units 72 (# 1),..., 72 (#n), respectively. The MMTP packet / IP packet output from the corresponding filter unit 72 is output to the corresponding switching point detection unit 74, and the MMTP packet (see FIG. 3) among the MMTP packets / IP packets output from the corresponding filter unit 72. The MPU sequence number is acquired from the MTTP payload (see FIG. 4) included in the reference), and the acquired MPU sequence number is output to the corresponding switching point detection unit 74.

  The switching control receiving unit 75 receives a request for switching between the main system and the redundant system from the external input device 100. Then, when the switching control reception unit 75 receives a switching request, the TLV multiplexing device 70 executes a process described later.

  Switching point detection units 74 (# 1),..., 74 (#n) are provided corresponding to the sequence number acquisition units 73 (# 1),. The MMTP packet / IP packet output from the corresponding sequence number acquisition unit 73 is output to the corresponding TLV packetization unit 77, and the sequence number output from the corresponding sequence number acquisition unit 73 is a predetermined value. (For example, 0) is detected. For example, the switching point detection unit 74 (# 1) detects that the sequence number output from the sequence number acquisition unit 73 (# 1) has reached a predetermined value (for example, 0). Similarly, the switching point detection unit 74 (# 2) detects that the sequence number output from the sequence number acquisition unit 73 (# 2) has reached a predetermined value (for example, 0), and detects the switching point. The unit 74 (# 3) detects that the sequence number output from the sequence number acquisition unit 73 (# 3) has reached a predetermined value (for example, 0), and the switching point detection unit 74 (#n) Detects that the sequence number output from the sequence number acquisition unit 73 (#n) has reached a predetermined value (for example, 0). In this way, each switching point detector 74 detects an MMTP packet / IP packet corresponding to a switching point between the main system and the redundant system. Then, the detection result is output to the null packet generator 79.

  TLV packetization units 77 (# 1),..., 74 (#n) are provided corresponding to the switching point detection units 74 (# 1),. The MMTP packet / IP packet output from the corresponding switching point detection unit 74 is input to generate a TLV packet, and the generated TLV packet is output to the multiplexing unit 76.

  The TLV-SI generation unit 78 generates TLV-SI and outputs it to the multiplexing unit 76.

  The null packet generation unit 79 generates an MMTP packet / IP packet corresponding to the switching point based on the detection result output from the switching point detection unit 74 (# 1), (# 2),..., (#N). A request signal for setting as a null packet is output to multiplexing section 76. The request signal includes identification information of the MMTP packet / IP packet corresponding to the switching point.

  The multiplexing unit 76, for each TLV packet output from the TLV packetizing unit 77, based on the identification information included in the request signal output from the null packet generation unit 79, the MMTP packet / IP corresponding to the identification information. The packet type of the TLV packet corresponding to the packet is set to a null packet, and the multiplexed MMTP packet / IP packet is output to the transmission unit 81.

  FIG. 6 is a diagram showing the structure of a TLV packet defined by ARIB STD-B32.

  “Packet type” in FIG. 6 is an area used to identify the type of packet stored in the TLV packet, and the assignment is as shown in FIG. The “data length” is an area in which the number of data bytes that follow is written.

  FIG. 7 is a diagram illustrating assignment of “packet type” in a TLV packet defined by ARIB STD-B32.

  As shown in FIG. 7, the “null packet” is a packet in which a byte string of 0xFF having a length indicated by “data length” is written in data. Therefore, in the TLV packet having the structure as shown in FIG. 6, the “packet type” is set to 0xFF, so that the packet becomes a null packet. In this way, the multiplexing unit 76 inserts the TLV packet of the packet type xFF corresponding to the switching point into the TLV packet corresponding to the MMTP packet / IP packet corresponding to the identification information.

  Thereafter, the transmission unit 81 outputs the TLV packet to the redundancy switching device 90. Accordingly, among the TLV packets output to the redundancy switching device 90, the TLV packet corresponding to the switching point is a null packet.

  Note that the null packet generation unit 79 can generate a TLV packet corresponding to the switching point in the following manner instead of the null packet. That is, as shown in FIG. 7, 0x04 to 0xFD of “packet type” are currently undefined. Therefore, any of 0x04 to 0xFD of “packet type” is newly assigned as a “switching point packet” indicating a switching point. For example, when the “packet type” is 0x04, the packet is defined as “switching point packet”, and the multiplexing unit 76 outputs the packet output from the null packet generation unit 79 to the TLV packet output from the TLV packetizing unit 77. Insert a TLV packet of type 0x04.

  Thereafter, the transmission unit 81 outputs the TLV packet to the redundancy switching device 90. In this case, among the TLV packets output to the redundancy switching device 90, the TLV packet corresponding to the switching point is a “switching point packet”.

(Redundant switching device)
FIG. 8 is a block diagram illustrating a configuration example of the redundancy switching device 90.

  The redundancy switching device 90 is a device for switching between the primary system and the redundant system, and includes a switching control reception unit 91, packet detection units 92 (# 1) and 92 (# 2), a packet identification unit 94, And a system switching unit 95 is provided.

  The switching control receiving unit 91 receives a request for switching between the main system and the redundant system from the external input device 100. Then, when the switching control receiving unit 91 receives a switching request, the redundancy switching device 90 executes processing for switching as described below.

  The packet detector 92 (# 1) is connected to the main system. That is, it is connected to the TLV multiplexing device 70 (# 1), detects the TLV packet output from the TLV multiplexing device 70 (# 1), and detects the detected TLV packet as a packet identification unit 94 and a system switching unit. Output to 95. Similarly, the packet detection unit 92 (# 2) connected to the redundant system detects the TLV packet output from the TLV multiplexing device 70 (# 2), and detects the detected TLV packet as the packet identification unit 94 and Output to the system switching unit 95.

  The packet identification unit 94 identifies a predetermined TLV packet from the TLV packets output from the packet detection units 92 (# 1) and 92 (# 2). The predetermined TLV packet is, for example, as described above, a null packet or a packet defined as a “switching point packet”.

  From the TLV packets output from the packet detectors 92 (# 1) and 92 (# 2), the packet identification unit 94 is a TLV packet that is a null packet or a TLV packet that is defined as a “switching point packet”. In addition, a predetermined TLV packet is identified. Then, the identification result of the TLV packet is output to the system switching unit 95.

  Based on the identification result of the TLV packet output from the packet identification unit 94 for the TLV packet output from the packet detection unit 92 (# 1) and 92 (# 2), the system switching unit 95 Switch over to the redundant system.

  In this way, the redundancy switching device 90 realizes seamless switching of TLV packets between the main system and the redundant system without performing data analysis.

(Overall operation of transmission system)
Next, the operation of the transmission system configured as shown in FIG. 1 will be described using the flowcharts of FIGS.

  For example, a video signal, an audio signal, and a caption signal are input to the main encoding device 20 (# 1) from a broadcast master system (not shown). Similarly, a video signal, an audio signal, and a caption signal are input to the redundant encoding device 20 (# 2), for example, from a broadcast master system (not shown) (S1).

  These signals are received by the signal encoding unit 23, and the signal encoding unit 23 performs encoding (compression) on the received signals, and the encoded video signal, audio signal, and subtitle signal are switched. The data is output to the information setting unit 24 and the MMTP packetizing unit 25, respectively.

  In this state, when the switching control reception unit 21 receives a switching request from the external input device 100 (S2), the encoding device 20 performs processing for switching as described below. .

  First, the GOP phase adjustment unit 22 generates an adjustment signal for aligning the GOP phases of the video signal, the audio signal, and the caption signal, and outputs the adjustment signal to the switching information setting unit 24 (S3).

  In the switching information setting unit 24, a predetermined value (for example, the MPU sequence number (FIG. 4) included in the MMTP packet (FIG. 4) corresponding to the switching point between the main system and the redundant system determined based on the adjustment signal is used. , 0) is generated (S4). This instruction input is output from the switching information setting unit 24 to the MMTP packetizing unit 25.

  Alternatively, in the switching information setting unit 24, the least significant bit of the time stamp field (FIG. 3) included in the MMTP packet corresponding to the switching point between the main system and the redundant system determined based on the adjustment signal is set to a predetermined value. An instruction input for setting to (for example, 0) is generated. Also in this case, the generated instruction input is output to the MMTP packetization unit 25.

  In the MMTP packetizing unit 25, the MMTP packets of the video signal, the audio signal, and the caption signal are output to the MMT multiplexing apparatus 30 in a state where the switching point can be identified (S6).

  In each of the MMT multiplexing devices 30 (# 1) and 30 (# 2), the MMTP packets (for example, MMTP packets of the video signal) output by the corresponding encoding devices 20 (# 1) and 20 (# 2), respectively. MMTP packets of audio signals and MMTP packets of subtitles) and data in the MMTP packet format output from an EPG (electronic program guide) transmission device (not shown) are multiplexed, and the multiplexed MMTP packets are of the same system The data is output to the scrambler 50 (S7).

  In the scramblers 50 (# 1) and 50 (# 2), an encryption for copyright protection is applied to the MMTP packets output from the corresponding MMT multiplexers 30 (# 1) and 30 (# 2). The encrypted MMTP packet is output to the IP multiplexer 60 of the same system (S8).

  In the IP multiplexers 60 (# 1) and 60 (# 2), the MMTP packets output from the corresponding scramblers 50 (# 1) and 50 (# 2) are IP packets from other devices not shown. Multiplexed with the format data (S9). Then, the MMTP packet / IP packet obtained as a result of multiplexing is output to the TLV multiplexing device 70 of the same system.

  In TLV multiplexers 70 (# 1) and 70 (# 2), MMTP packets / IP packets output from IP multiplexers 60 of the same system are received by receivers 71 (# 1) provided for each signal type. ,..., 71 (#n) and output to the corresponding filter units 72 (# 1),. Then, each of the filter units 72 (# 1),..., 72 (#n) performs the filtering process, and the filtered MMTP packet / IP packet is output to the corresponding sequence number acquisition unit 73 (S10). ).

  In each sequence number acquisition unit 73 (# 1),..., 73 (#n), the MMTP packet / IP packet output from the corresponding filter unit 72 is output to the corresponding switching point detection unit 74. . Also, the MPU sequence number is acquired from the MTTP payload (see FIG. 4) included in the MMTP packet (see FIG. 3) of the MMTP / IP packets output from the corresponding filter unit 72, and the corresponding switching inspection is performed. The data is output to the output unit 74 (S11).

  The switching control receiving unit 75 receives a request for switching between the main system and the redundant system from the external input device 100. When the switching control reception unit 75 receives a switching request (S12), each switching point detection unit 74 (# 1),..., 74 (#n) receives a corresponding sequence number from the corresponding sequence number acquisition unit 73. The output MMTP packet / IP packet is output to the corresponding TLV packetization unit 77. Further, it is detected that the sequence number output from the corresponding sequence number acquisition unit 73 has reached a predetermined value (for example, 0), and the detection result is output to the null packet generation unit 79 (S13).

  The TLV packetization unit 77 generates a TLV packet from the MMTP packet, and outputs the generated TLV packet to the multiplexing unit 76 (S14).

  In the TLV-SI generation unit 78, TLV-SI is generated and output to the multiplexing unit 76. The null packet generator 79 nulls the MMTP packet / IP packet corresponding to the switching point based on the detection result output from the switching point detector 74 (# 1),..., 74 (#n). A request signal for setting as a packet is output to multiplexing section 76. The request signal includes identification information of the MMTP packet corresponding to the switching point.

  In the multiplexing unit 76, for each TLV packet output from each TLV packetizing unit 77, an MMTP / IP packet corresponding to the identification information based on the identification information included in the request signal output from the null packet generation unit 79 The packet type of the TLV packet corresponding to is set to a null packet, and the multiplexed MMTP / IP packet is output to the transmission unit 81. The MMTP / IP packet is output from the transmission unit 81 to the redundancy switching device 90 (S15). Thereby, among the TLV packets output to the redundancy switching device 90, the TLV packet corresponding to the switching point is a null packet.

  Note that the multiplexing unit 76 newly assigns, for example, any of 0x04 to 0xFD of “packet type” that is currently undefined as a “switching point packet” indicating a switching point, and from the null packet generation unit 79. Based on the identification information included in the output request signal, the packet type of the corresponding TLV packet may be set to 0x04. Thereby, among the TLV packets output to the redundancy switching device 90, the TLV packet corresponding to the switching point is set as the “switching point packet”.

  In the redundant switching device 90, when the switching control receiving unit 91 receives a request for switching between the primary system and the redundant system from the external input device 100 (S16), the redundant switching device 90 operates as follows.

  That is, the TLV packet output from the main TLV multiplexer 70 (# 1) is detected by the packet detection unit 92 (# 1), and the detected TLV packet is transmitted to the packet identification unit 94 and the system switching unit. 95 is output. Further, the TLV packet output from the redundant TLV multiplexing device 70 (# 2) is detected by the packet detection unit 92 (# 2), and the detected TLV packet is transmitted to the packet identification unit 94 and the system switching unit. (S17).

  The packet identification unit 94 identifies TLV packets having a predetermined multiplex configuration from the TLV packets output from the packet detection units 92 (# 1) and 92 (# 2) (S18). A TLV packet having a predetermined multiplex configuration is, for example, a null packet or a packet defined as a “switching point packet” as described above.

  As described above, the packet identification unit 94 is defined as a TLV packet that is a null packet or a “switching point packet” from the TLV packets output from the packet detection units 92 (# 1) and 92 (# 2). Like a TLV packet, a TLV packet having a predetermined multiplex configuration is identified. Then, the identified TLV packet is output to the system switching unit 95.

  The system switching unit 95 switches between the primary system and the redundant system in the TLV packet output from the packet identification unit 94 with respect to the TLV packet output from the packet detection units 92 (# 1) and 92 (# 2). Is implemented (S19).

  In this way, the redundancy switching device 90 realizes seamless switching of TLV packets between the main system and the redundant system without analyzing data.

  As described above, according to the transmission system to which the transmission method of the present embodiment is applied, the TLV multiplexing device 70 can identify the switching point of the TLV packet between the primary system and the redundant system. As a result, the redundancy switching device 90 can perform seamless switching of TLV packets between the main system and the redundant system without analyzing data such as video and audio.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  10 packet transmission system, 20 encoding device, 21 switching control reception unit, 22 GOP phase adjustment unit, 23 signal encoding unit, 24 switching information setting unit, 25 MMTP packetizing unit, 30 MMT multiplexing device, 50 scrambler, 60 IP multiplexer, 70 TLV multiplexer, 71 receiver, 72 filter, 73 sequence number acquisition unit, 74 switching point detector, 75 switching control receiver, 76 multiplexer, 77 TLV packetizer, 78 TLV -SI generation unit, 79 null packet generation unit, 81 transmission unit, 90 redundant switching device, 91 switching control reception unit, 92 packet detection unit, 94 packet identification unit, 95 system switching unit, 100 external input device.

Claims (6)

A multiplexing device applied to a transmission system including a main system and a redundant system for transmitting a TLV packet, and provided in each of the main system and the redundant system,
A detection unit for detecting an MMTP packet corresponding to a switching point between the main system and the redundant system from an MMTP (MPEG Media Transport Protocol) packet converted into the TLV packet;
A conversion unit for converting the MMTP packet into the TLV packet;
A generation unit that generates a TLV packet corresponding to the switching point detected by the detection unit;
A multiplexing apparatus comprising:   The multiplexing device according to claim 1, wherein the generation unit generates a TLV packet corresponding to the switching point detected by the detection unit as a null packet. A switching device applied to a transmission system including a main system and a redundant system for transmitting a TLV packet, for switching between the main system and the redundant system,
A detection unit for detecting an input TLV packet;
An identification unit for identifying a predetermined TLV packet from the TLV packet detected by the detection unit;
A switching unit that performs switching between the main system and the redundant system in the predetermined TLV packet;
A switching device comprising:   The switching device according to claim 3, wherein the predetermined TLV packet is a null packet. A transmission system having a main system and a redundant system for transmitting TLV packets,
A multiplexing device provided in each of the main system and the redundant system;
A switching device for performing switching between the main system and the redundant system;
The multiplexing device comprises:
A first detection unit for detecting an MMTP packet corresponding to a switching point between the main system and the redundant system from an MMTP (MPEG Media Transport Protocol) packet converted into the TLV packet;
A conversion unit for converting the MMTP packet into the TLV packet;
A generation unit that generates a TLV packet corresponding to the switching point detected by the first detection unit,
The switching device is
A second detection unit for detecting the generated TLV packet;
An identification unit for identifying a TLV packet corresponding to the switching point generated by the generation unit from the TLV packet detected by the second detection unit;
A transmission system comprising: a switching unit configured to perform switching between the main system and the redundant system in the identified TLV packet. A transmission method applied to a transmission system including a main system and a redundant system for transmitting a TLV packet,
In the multiplexing device provided in each of the main system and the redundant system,
From an MMTP (MPEG Media Transport Protocol) packet converted to the TLV packet, an MMTP packet corresponding to a switching point between the main system and the redundant system is detected,
Converting the MMTP packet into the TLV packet;
Generating a TLV packet corresponding to the detected switching point;
In a switching device for performing switching between the main system and the redundant system,
Detecting the generated TLV packet;
A transmission method in which, when a TLV packet corresponding to the generated switching point is identified from the detected TLV packet, switching between the main system and the redundant system is performed in the identified TLV packet. .