WO2018110478A1 - Reception device and communication system - Google Patents

Abstract

[Problem] To provide a reception device in which MMTP packets can be recovered in an appropriate order even when a leap second is inserted. [Solution] A recovery unit 36 recovers data from a MMTP packet transmitted by a transmission device. At a time of a leap second which is inserted in order to keep Coordinated Universal Time close to universal time, a time monitoring unit 51 inputs, to the recovery unit 36, insertion ongoing information indicating that the time is at the leap second. A count unit 35 inputs, to the recovery unit 36, time information indicating the current time on the basis of Coordinated Universal Time. In addition, in a case where the MMTP packet was generated at a timing corresponding to the leap second, the MMTP packet includes leap second information indicating that the MMTP packet was generated at the leap second. If the MMTP packet includes the leap second information indicating that the MMTP packet was generated at the leap second, the recovery unit 36 recovers the MMTP packet at a timing based on the time information that was inputted from the count unit 35 when the insertion ongoing information was inputted.

Description

Reception device and communication system

The present invention relates to a receiving apparatus that performs communication of MMTP packets, and a communication system.

In television broadcasting, in order to improve the quality of video and audio to be output to a receiving device or to increase the number of types, it is considered to transmit more information to the receiving device.

Non-Patent Document 1 describes a system that transmits and receives more information via broadcasting and communication lines.

In the system described in Non-Patent Document 1, information corresponding to the date and time of playback is generated based on the NTP (Network Time Protocol) time stamp so that the receiving device can play back in an appropriate order. And transmitted in association with television program information or the like. Here, the time stamp of NTP refers to information indicating the date and time based on the NTP by the number of seconds accumulated from a predetermined date and time. Hereinafter, for simplicity of explanation, the date and time is also simply referred to as time. The receiving device reproduces video and audio based on the television program information in an appropriate order based on the separately acquired NTP time stamp and the time information associated with the television program information.

NTP time stamps are based on Coordinated Universal Time. Coordinated universal time is adjusted once every few years to approximate universal time. The adjustment is performed by inserting leap seconds or deleting leap seconds. Specifically, when leap seconds are inserted, for example, a series of 8:59:59 (hereinafter referred to as “8: 59: 55: 00”) to 8: 59: 59: 99 A time stamp is generated twice in succession. When the leap second is deleted, a time stamp indicating the next second of 8: 59: 58: 00 is generated to indicate 9: 00: 00: 00.

Non-Patent Document 1 describes a digital broadcasting system based on MMT (MPEG (Moving Picture Experts Group) Media Transport). In the system described in Non-Patent Document 1, the presentation time of an MPU (Media Processing Unit) is indicated in a time stamp descriptor in the MPU and transmitted. In the system described in Non-Patent Document 1, when performing leap second adjustment, the transmission side sets a predetermined flag in the extended time stamp descriptor of the MPU and transmits the MPU.

Patent Document 1 describes that when leap second adjustment is performed, the transmission side corrects the time indicated in the MPU time stamp descriptor and transmits correction information indicating the correction.

JP 2016-1000089 A2

“Media transport system using digital broadcasting with MMT version 1.7”, [online], July 2016, Radio Industry Association, [searched on September 28, 2016], Internet <URL: http: // www.arib.or.jp/english/html/overview/doc/2-STD-B60v1_7.pdf>

In the system described in Non-Patent Document 1, the MPU is divided into MMTP (MMT Protocol) packets and transmitted / received. Each MMTP packet is restored on the receiving side at a timing according to the value indicated in the Timestamp field in the MMTP packet header.

FIG. 6 is an explanatory diagram showing an example of the timing for generating and restoring the MMTP packet. In FIG. 6, the middle stage shows the timing at which the transmission apparatus generates the MMTP packet. In FIG. 6, the lower part shows the timing at which the transmission apparatus restores the main signal data by performing restoration processing on the MMTP packet (hereinafter, also simply referred to as restoration of the MMTP packet).

As shown in FIG. 6, the transmission apparatus includes time stamp information indicating the time corresponding to the timing at which the main signal data is input, including the main signal data in the payload according to the order in which the main signal data is input. Are sequentially generated. Therefore, the time stamp information corresponds to the Timestamp field in the system described in Non-Patent Document 1.

As shown in the middle part of FIG. 6, the time indicated by the time stamp information in the MMTP packet generated when the leap second is inserted does not correspond to the order in which the MMTP packets are generated. Specifically, an MMTP packet (MMTP packet numbered (8) in FIG. 6) generated when a leap second is inserted and including time stamp information indicating 8: 59: 59: 200 is 8 MMTP packet including time stamp information indicating 59: 59: 300 (MMTP packet numbered (5) in FIG. 6), and MMTP packet including time stamp information indicating 8: 59: 59: 500 (FIG. 6). MMTP packets numbered (6) in FIG. 6) and MMTP packets including time stamp information indicating 8: 59: 59: 800 (MMTP packets numbered (7) in FIG. 6). ing. An MMTP packet (MMTP packet numbered (9) in FIG. 6) that is generated when a leap second is inserted and includes time stamp information indicating 8: 59: 59: 600 is 8:59: It is generated after an MMTP packet including time stamp information indicating 59: 800 (MMTP packet numbered (7) in FIG. 6).

That is, as shown in FIG. 6, each MMTP packet generated in the period A that is 1 second immediately before the leap second and numbered (5) to (7) is inserted in the inserted leap second period. It is generated prior to each MMTP packet generated during a period B and numbered (8) to (10). Further, as shown in FIG. 6, each MMTP packet numbered (5) to (10) is generated in the order in which small values are numbered.

However, when the restoration process is performed on the MMTP packets at the timing indicated by the time stamp information, the main signal data is restored in an order different from the input order. Further, the main signal data included in the MMTP packet including the time stamp information indicating the time corresponding to the leap second is restored at a timing different from the input timing.

Then, when the leap second is inserted, in the system described in Non-Patent Document 1, each MMTP packet is restored at a timing according to the value indicated in the Timestamp field in the MMTP packet header. The MMTP packets are not restored in the proper order and timing.

Specifically, as shown in the lower part of FIG. 6, the MMTP packet numbered (8) is subjected to the restoration process before the MMTP packets numbered (5) to (7). . As a result, the main signal data based on the MMTP packets numbered (8) is restored before the main signal data based on the MMTP packets numbered (5) to (7). Further, as shown in the lower part of FIG. 6, the MMTP packet numbered (9) is subjected to the restoration process before the MMTP packet numbered (7). Then, the main signal data based on the MMTP packet numbered (9) is restored before the main signal data based on the MMTP packet numbered (7).

Then, there arises a problem that video and audio based on television program information or the like cannot be reproduced in an appropriate order.

In the invention described in Patent Document 1, the MPU restoration order is examined, but the MMTP packet restoration order is not considered.

Therefore, an object of the present invention is to provide a receiving apparatus and a communication system that can restore each MMTP packet in an appropriate order even when leap seconds are inserted.

The receiving device according to the present invention has a leap second when it is a leap second which is a time inserted to restore the coordinated universal time and a restoring means for restoring data from the MMTP packet transmitted by the transmitting device. Is installed on the broadcast receiving side and includes a time monitoring means for inputting in-insertion information indicating to the restoration means and a counting means for inputting time information indicating the current time to the restoration means based on the coordinated universal time, and is provided in the MMTP packet. Includes the leap second information indicating that the leap second was generated when the leap second was generated at the timing according to the leap second, and the restoration unit indicated the leap second information indicating that the leap second was generated in the MMTP packet. Is included, the MMTP packet is restored at a timing based on the time information input by the counting means when the information being inserted is input. .

The communication system according to the present invention includes any one of the receiving apparatuses and any one of the transmitting apparatuses.

According to the present invention, each MMTP packet can be restored in an appropriate order even when the NTP time stamp is adjusted.

It is a block diagram which shows the structural example of the information communication system of the 1st Embodiment of this invention. It is explanatory drawing which shows the example of the decompression | restoration process which decompress | restores main signal data in a MMTP packet decompression | restoration part. It is a flowchart which shows operation | movement of the transmitter in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the receiver in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the receiver of 2nd Embodiment. It is explanatory drawing which shows the example of the timing which a MMTP packet is produced | generated, and the timing which is decompress | restored.

Embodiment 1. FIG.
An information communication system 100 according to the first embodiment will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of an information communication system 100 according to the first embodiment. As illustrated in FIG. 1, the information communication system 100 according to the first embodiment includes a transmission device 200 and a reception device 300. The transmission device 200 and the reception device 300 are connected to a communication network 400 such as the Internet, for example. The transmission device 200 and the reception device 300 transmit / receive information to / from each other via the communication network 400.

Also, it is assumed that the receiving device 300 can receive the information transmitted by the transmitting device 200 via broadcasting.

The transmission device 200 is installed in a television broadcasting station, for example. The receiving apparatus 300 is built in or connected to, for example, a television broadcast receiver or a set top box. Note that the receiving device 300 may be installed in, for example, a television broadcasting station, and configured to output a signal from the receiving device 300 so as to be received by a television broadcast receiver or a set-top box. .

A configuration example of the transmission device 200 will be described. As illustrated in FIG. 1, the transmission apparatus 200 includes a clock signal generation unit 210, an NTP counter unit 220, an MMTP packetization processing unit 230, an NTP packet generation unit 240, and a multiplexing unit 250.

The NTP counter unit 220, the MMTP packetization processing unit 230, the NTP packet generation unit 240, and the multiplexing unit 250 are realized by, for example, a CPU (Central Processing Unit) that executes processing according to program control and a plurality of circuits. .

The clock signal generation unit 210 generates a clock signal having a predetermined frequency and inputs it to the NTP counter unit 220. The clock signal generation unit 210 generates a clock signal with a frequency of 2 ³² Hz or a clock signal with a frequency of 2 ²⁴ to 2 ²⁸ Hz, for example.

The NTP counter unit 220 receives the clock signal input by the clock signal generation unit 210 and the external time information transmitted from the external server. The external time information transmitted from the external server is, for example, an NTP format signal transmitted from the NTP server, and at least a signal indicating a time and a leap second indicator. The leap second indicator is, for example, a descriptor indicating that a leap second is inserted in the last minute of the current month. Specifically, when a leap second is inserted in the last minute of the current month, a value “1” is set to the leap second indicator, otherwise a value “0” is set to the leap second indicator. Set.

The NTP counter unit 220 generates NTP time information indicating the current time according to the NTP format based on the clock signal input by the clock signal generation unit 210. Specifically, for example, based on the NTP format, the NTP counter unit 220 generates NTP time information indicating the current date and time (also simply referred to as time for simplicity of explanation) based on the number of seconds accumulated from a predetermined date and time. . Note that the NTP time information includes the leap second indicator indicated in the input external time information. Therefore, the time indicated by the NTP time information is a time based on the clock signal input by the clock signal generation unit 210, and the value set in the leap second indicator is set in the leap second indicator of the external time information. Value.

Then, the NTP counter unit 220 inputs the generated NTP time information to the MMTP packetization processing unit 230 and the NTP packet generation unit 240.

As shown in FIG. 1, the NTP counter unit 220 determines whether or not the time indicated by the NTP time information generated by the NTP counter unit 220 is a leap second time. including.

When the transmission side leap second monitoring unit 221 determines that the time indicated by the NTP time information is a time in leap second, the MMTP packetization processing unit 230 sets leap second inserting information indicating that the leap second is inserted. To enter.

In addition, when the leap second indicator is inserted by the leap second indicator in the time information input to the NTP counter unit 220, the transmission-side leap second monitoring unit 221 specifically, for example, When the value “1” is set in the second indicator, leap second insertion information is input to the MMTP packetization processing unit 230 when generating NTP time information indicating the time when the leap second is inserted. To do.

The MMTP packetization processing unit 230 includes time stamp information indicating time according to the time indicated by the NTP time information input by the NTP counter unit 220 and leap second information in the header, and the input main signal data is included in the payload. An included MMTP packet is generated. The MMTP packetization processing unit 230 generates an MMTP packet including leap second information indicating that the leap second has been generated in the header when the transmission side leap second monitoring unit 221 inputs the leap second insertion in-progress information. To do. Further, the MMTP packetization processing unit 230 includes leap second information indicating that it is generated when it is not leap second when the transmission side leap second monitoring unit 221 does not input leap second insertion in-progress information. Generate an MMTP packet. Then, the MMTP packetization processing unit 230 inputs the generated MMTP packet to the multiplexing unit 250. The leap second information is, for example, a predetermined flag in the header of the MMTP packet, and when the value of the flag is set to “1”, it indicates that the MMTP packet was generated in leap seconds, If the flag value is set to “0”, it indicates that the MMTP packet was generated when it was not a leap second.

Note that the MMTP packetization processing unit 230 generates time stamp information indicating the time taking into account the time required for decoding the main signal data, etc., at the time indicated by the NTP time information input by the NTP counter unit 220.

Here, when leap seconds are inserted, for example, 8: 59: 59: 000 to 8: 59: 59: 999 are repeated twice. Therefore, a series of NTP time information indicating, for example, 8: 59: 59: 000 to 8: 59: 59: 999 is input to the MMTP packetization processing unit 230 twice in succession. The MMTP packetization processing unit 230 receives NTP time information indicating 8: 59: 59: 000 to 8: 59: 59: 999 for the second time out of the NTP time information generated twice consecutively. In this case, leap second insertion information is input.

Therefore, when the leap second insertion information is input, the MMTP packetization processing unit 230 includes the time stamp information indicating the time corresponding to the time indicated by the NTP time information and the leap second information indicating that the leap second is generated. And an MMTP packet including the header. That is, the MMTP packetization processing unit 230 inserts the leap second, and for example, when 8: 59: 59: 000 to 8: 59: 59: 999 is repeated twice, the second 8:59:59 : 000 to 8: 59: 59: 999, the header includes time stamp information indicating the time according to the time indicated by the NTP time information and leap second information indicating that it was generated in leap seconds, An MMTP packet including the input main signal data in the payload is generated. Therefore, two sets of MMTP packets including time stamp information indicating the time corresponding to the time indicated by the NTP time information indicating 8: 59: 55: 00 to 8: 59: 59: 99 in the header are generated. The header of the MMTP packet includes leap second information indicating that it was generated in leap seconds, and the header of the other pair of MMTP packets indicates leap seconds indicating that they are generated when they are not leap seconds. Contains information.

The NTP packet generation unit 240 generates an NTP packet including the NTP time information input by the NTP counter unit 220. Then, the NTP packet generation unit 240 inputs the generated NTP packet to the multiplexing unit 250. Therefore, for example, the NTP packet generation unit 240 generates an NTP packet including NTP time information indicating the time at which the MMTP packet multiplexed by the multiplexing unit 250 described later is generated.

The multiplexing unit 250 generates an IP (Internet Protocol) packet in which the MMTP packet input by the MMTP packetization processing unit 230 and the NTP packet generated by the NTP packet generation unit 240 are multiplexed. Then, multiplexing unit 250 transmits the generated IP packet to receiving apparatus 300. The transmitted IP packet is received by the receiving device 300 via the communication network 400.

A configuration example of the receiving device 300 will be described. As illustrated in FIG. 1, the receiving apparatus 300 includes a demultiplexing unit 310, an NTP packet receiving unit 320, a comparison unit 330, a clock signal generation unit 340, an NTP counter unit 350, and an MMTP packet restoration unit 360.

The demultiplexing unit 310, the NTP packet receiving unit 320, the comparing unit 330, the clock signal generating unit 340, the NTP counter unit 350, and the MMTP packet restoring unit 360 include, for example, a CPU that executes processing according to program control, Realized by the circuit.

The demultiplexing unit 310 demultiplexes the IP packet into the NTP packet and the MMTP packet when receiving the IP packet transmitted by multiplexing the MMTP packet and the NTP packet. Then, the demultiplexing unit 310 inputs the demultiplexed NTP packet to the NTP packet receiving unit 320, and inputs the MMTP packet to the MMTP packet restoration unit 360.

The NTP packet receiving unit 320 restores the NTP time information based on the input NTP packet. Then, the NTP packet receiving unit 320 inputs the restored NTP time information that is the restored NTP time information to the comparison unit 330 and the NTP counter unit 350. The restored NTP time information corresponds to the NTP time information generated by the NTP counter unit 220. Therefore, the restored NTP time information includes a leap second indicator.

The comparison unit 330 and the clock signal generation unit 340 constitute a PLL (Phase Locked Loop). Specifically, the comparison unit 330 compares the time indicated by the restored NTP time information with the time indicated by the generated NTP time information that is the time information generated by the NTP counter unit 350. The generated NTP time information will be described later.

Then, the comparison unit 330 inputs a signal corresponding to the comparison result to the clock signal generation unit 340.

The clock signal generation unit 340 generates a clock signal corresponding to the signal input by the comparison unit 330. Then, the clock signal generation unit 340 inputs the generated clock signal to the NTP counter unit 350. Note that the clock signal generation unit 340 generates a clock signal having a frequency of, for example, 2 ³² Hz or a clock signal having a frequency of 2 ²⁴ to 2 ²⁸ Hz in accordance with the signal input by the comparison unit 330.

The NTP counter unit 350 generates generated NTP time information indicating the current time according to the NTP format based on the clock signal input by the clock signal generation unit 340. Specifically, the NTP counter unit 350 generates generated NTP time information that indicates the current date and time (also simply referred to as time for simplicity of explanation) based on the number of seconds accumulated from a predetermined date and time, for example, based on the NTP format. To do. Then, the NTP counter unit 350 inputs the generated generated NTP time information to the comparison unit 330 and the MMTP packet restoration unit 360.

As shown in FIG. 1, the NTP counter unit 350 is configured to determine whether the time indicated by the generated NTP time information generated by the NTP counter unit 350 is a leap second time. 351.

If the reception-side leap second monitoring unit 351 determines that the time indicated by the generated NTP time information is the time in leap seconds, the MMTP packet restoration unit 360 displays leap second insertion information indicating that leap seconds are inserted. To enter.

Note that the reception-side leap second monitoring unit 351, when the leap second is indicated by the leap second indicator in the restored NTP time information input to the NTP counter unit 350, specifically, for example, When the value “1” is set in the leap second indicator, the leap second inserting information is input to the MMTP packet restoration unit 360 together with the generated NTP time information indicating the time when the leap second is inserted.

The MMTP packet restoration unit 360 performs a restoration process for restoring the main signal data from the MMTP packet at a timing corresponding to the time indicated by the time stamp information included in the header of the MMTP packet. .

Specifically, the MMTP packet restoration unit 360 includes, for example, an MMTP including the time stamp information at a timing according to the time indicated by the generated NTP time information input by the NTP counter unit 350 and the time indicated by the time stamp information. A restoration process for restoring the main signal data from the packet is performed. More specifically, for example, the MMTP packet restoration unit 360 includes the time stamp information at a timing when the time indicated by the generated NTP time information input by the NTP counter unit 350 matches the time indicated by the time stamp information. A restoration process for restoring the main signal data from the MMTP packet is performed.

Note that when leap seconds are inserted, the time stamp information can indicate the same time in different MMTP packets.

Specifically, when a leap second is inserted, the MMTP packet restoration unit 360 receives, for example, two MMTP packets including time stamp information indicating 8: 59: 59: 000 to 8: 59: 59: 999. Pair input. Of the two sets of MMTP packets, one set of MMTP packets generated at the time when the second 8: 59: 59: 000 to 8: 59: 59: 999 arrives is generated in leap seconds. It includes leap second information indicating that this has been done.

Therefore, the time indicated by the generated NTP time information input from the NTP counter unit 350 together with the leap second inserting information indicating that the leap second is inserted, which is input from the reception-side leap second monitoring unit 351, and one of the sets The main signal data is restored from the MMTP packet including the time stamp information at a timing corresponding to the time indicated by the time stamp information included in the MMTP packet. More specifically, the MMTP packet restoration unit 360 is input from the NTP counter unit 350 together with the leap second insertion in-progress information indicating that the leap second is inserted, which is input from the reception-side leap second monitoring unit 351, for example. Restoration for restoring main signal data from the MMTP packet including the time stamp information at a timing when the time indicated by the generated NTP time information matches the time indicated by the time stamp information included in the one set of MMTP packets Process.

Then, the MMTP packet restoration unit 360 outputs the restored main signal data.

FIG. 2 is an explanatory diagram showing an example of restoration processing for restoring the main signal data in the MMTP packet restoration unit 360. In this example, the time when the generation of the MMTP packet is started is set as the time when the MMTP packet is generated, but the time when generation of the MMTP packet is ended may be set as the time when the MMTP packet is generated. Other timing such as the timing at which the encoding process of the main signal data is completed may be the time when the MMTP packet is generated.

As shown in FIG. 2, the time indicated by the time stamp information in the MMTP packet generated when the leap second is inserted does not correspond to the order in which the MMTP packets are generated. Specifically, an MMTP packet (MMTP packet numbered (8) in FIG. 2) that is generated when a leap second is inserted and includes time stamp information indicating 8: 59: 59: 200 is 8 MMTP packet including time stamp information indicating 59: 59: 300 (MMTP packet numbered (5) in FIG. 2), MMTP packet including time stamp information indicating 8: 59: 59: 500 (FIG. 2) MMTP packets numbered (6) in FIG. 2) and MMTP packets including time stamp information indicating 8: 59: 59: 800 (MMTP packets numbered (7) in FIG. 2). ing. An MMTP packet (MMTP packet numbered (9) in FIG. 2) that is generated when a leap second is inserted and includes time stamp information indicating 8: 59: 59: 600 is 8:59: It is generated after the MMTP packet including the time stamp information indicating 59: 800 (the MMTP packet numbered (7) in FIG. 2).

That is, as shown in FIG. 2, each MMTP packet generated during period A and numbered (5) to (7) is generated during period B, which is an inserted leap second (8). It is generated before each MMTP packet numbered with (10) to (10). Then, as shown in FIG. 2, the MMTP packets numbered (5) to (10) are generated in the order in which small values are numbered.

Also, each MMTP packet numbered (8)-(10) is generated in leap seconds by leap second information of each MMTP packet numbered (8)-(10) generated during period B It has been shown. When the MMTP packets numbered (5) to (7) are not leap seconds by the leap second information of the MMTP packets numbered (5) to (7) generated during the period A It is shown that it was generated.

Therefore, the MMTP packet restoration unit 360 generates an MMTP packet including leap second information indicated to have been generated in leap seconds from the NTP counter unit 350 together with leap second inserting information indicating that it has been generated in leap seconds. It is restored at a timing based on the time indicated by the input generated NTP time information.

Specifically, in the example shown in FIG. 2, leap second information indicating that the MMTP packets numbered (1) to (7) and (11) to (13) are generated when they are not leap seconds. It is included. In the example shown in FIG. 2, the MMTP packets numbered (8) to (10) include leap second information indicating that they are generated in leap seconds.

Therefore, the MMTP packet restoration unit 360 inserts the MMTP packet numbered (1) to (7) and (11) to (13) with the time indicated by the time stamp information included in the MMTP packet and the leap second. At a timing when the time indicated by the generated NTP time information input by the NTP counter unit 220 when no information is input matches, a restoration process is performed to restore the main signal data from the MMTP packet including the time stamp information. Also, the MMTP packet restoration unit 360 inputs the MMTP packets numbered (8) to (10) from the NTP counter unit 350 together with the time indicated by the time stamp information included in the MMTP packet and the leap second insertion information. At the timing when the time indicated by the generated NTP time information coincides, a restoration process for restoring the main signal data from the MMTP packet including the time stamp information is performed.

Then, as shown in the lower part of FIG. 2, the MMTP packet restoration unit 360 performs restoration processing on the MMTP packets in ascending order of the assigned numbers, that is, in the order of generation.

Next, the operation of the transmission device 200 in the first embodiment will be described. FIG. 3 is a flowchart illustrating the operation of the transmission apparatus 200 according to the first embodiment. As shown in FIG. 3, in the transmission apparatus 200, the clock signal generation unit 210 generates a clock signal having a predetermined frequency and inputs the clock signal to the NTP counter unit 220 (step S101).

The NTP counter unit 220 generates NTP time information indicating the current time according to the NTP format based on the clock signal input by the clock signal generation unit 210 (step S102). Then, the NTP counter unit 220 inputs the generated NTP time information to the MMTP packetization processing unit 230 and the NTP packet generation unit 240 (step S103).

Further, when the transmission-side leap second monitoring unit 221 determines that the time indicated by the NTP time information is a time in leap seconds (Y in step S104), the transmission side leap second monitoring unit 221 indicates that the leap second is inserted together with the NTP time information. The indicated leap second insertion information is input to the MMTP packetization processing unit 230 (step S105).

The MMTP packetization processing unit 230 includes, in a header, time stamp information indicating the time indicated by the NTP time information input by the NTP counter unit 220, and leap second information according to whether leap second insertion information is input. Then, an MMTP packet including the input main signal data in the payload is generated (step S106).

Also, the NTP packet generation unit 240 generates an NTP packet indicating the time indicated by the NTP time information based on the NTP time information input by the NTP counter unit 220 in the process of step S103 (step S107).

The multiplexing unit 250 generates an IP packet in which the MMTP packet input by the MMTP packetization processing unit 230 and the NTP packet generated by the NTP packet generation unit 240 are multiplexed (step S108). Then, multiplexing unit 250 transmits the generated IP packet to receiving apparatus 300.

Next, the operation of the receiving device 300 in the first embodiment will be described. FIG. 4 is a flowchart illustrating the operation of the reception device 300 according to the first embodiment. As illustrated in FIG. 4, in the receiving apparatus 300, when the demultiplexing unit 310 receives an IP packet that is transmitted by multiplexing an MMTP packet and an NTP packet, the demultiplexing unit 310 converts the IP packet into an NTP packet and an MMTP packet. (Step S201). Then, the demultiplexing unit 310 inputs the demultiplexed NTP packet to the NTP packet receiving unit 320, and inputs the MMTP packet to the MMTP packet restoration unit 360.

The NTP packet receiving unit 320 restores NTP time information based on the input NTP packet (step S202).

The comparing unit 330 compares the time indicated by the restored NTP time information that is the restored NTP time information with the time indicated by the generated NTP time information that is the time information generated by the NTP counter unit 350 (step S203). The comparison unit 330 inputs a signal corresponding to the comparison result to the clock signal generation unit 340.

The clock signal generation unit 340 generates a clock signal corresponding to the signal input by the comparison unit 330 (step S204). The clock signal generation unit 340 inputs the clock signal generated in the process of step S204 to the NTP counter unit 350.

The NTP counter 350 generates generated NTP time information indicating the current time according to the NTP format based on the clock signal input by the clock signal generator 340 (step S205), and inputs the generated NTP time information to the MMTP packet restoration unit 360.

When the reception-side leap second monitoring unit 351 determines that the time indicated by the generated NTP time information is a leap second time (Y in step S206), leap second insertion-in-progress information indicating that a leap second has been inserted. Is input to the MMTP packet restoration unit 360 (step S207).

When the input MMTP packet includes leap second information indicating that it has been generated in leap seconds (Y in step S208), the MMTP packet restoration unit 360 generates the MMTP packet in leap seconds. It is restored at a timing based on the time indicated by the generated NTP time information input from the NTP counter unit 350 together with the leap second insertion in-progress information indicating this (step S209).

In addition, when the input MMTP packet includes leap second information indicating that it was generated when it is not leap second (N in step S208), the MMTP packet restoration unit 360 converts the MMTP packet to leap second. Restoration is performed at a timing based on the time indicated by the generated NTP time information input from the NTP counter unit 350 when the information being inserted is not input (step S210).

Then, the MMTP packet restoration unit 360 outputs the restored main signal data.

According to this embodiment, when it is leap second, the MMTP packetization processing unit 230 generates an MMTP packet including leap second information indicating leap second. Then, the multiplexing unit 250 multiplexes the generated MMTP packet and the NTP packet according to the current time, and transmits the multiplexed packet to the receiving apparatus 300.

In the receiving apparatus 300, when it is leap second, the MMTP packet restoration unit 360 restores the MMTP packet including leap second information indicating leap second. Therefore, the receiving apparatus 300 can restore the MMTP packet at an appropriate timing even when leap seconds are inserted.

Therefore, the receiving apparatus 300 can restore each MMTP packet at an appropriate timing and appropriately output main signal data included in the payload of the MMTP packet even when leap seconds are inserted. it can.

Embodiment 2. FIG.
Next, the receiving apparatus 30 of 2nd Embodiment is demonstrated with reference to drawings. FIG. 5 is a block diagram illustrating a configuration example of the receiving device 30 according to the second embodiment. As shown in FIG. 5, the receiving device 30 according to the second embodiment includes a restoration unit 36, a time monitoring unit 51, and a counting unit 35, and is installed on the broadcast receiving side.

The restoration unit 36 corresponds to, for example, the MMTP packet restoration unit 360 in the first embodiment shown in FIG. The time monitoring unit 51 corresponds to, for example, the reception leap second monitoring unit 351 in the first embodiment shown in FIG. The count unit 35 corresponds to, for example, the NTP counter unit 350 in the first embodiment shown in FIG.

The restoration unit 36 restores data from the MMTP packet transmitted by the transmission device (corresponding to the transmission device 200 in the first embodiment shown in FIG. 1).

The time monitoring unit 51 inputs the in-insertion information indicating the leap second to the restoration unit 36 when the leap second is the time inserted to approximate the coordinated universal time.

The count unit 35 inputs time information indicating the current time to the restoration unit 36 based on the coordinated universal time.

In addition, the MMTP packet includes leap second information indicating that it was generated in leap seconds when generated at a timing corresponding to leap seconds.

Then, when the MMTP packet includes leap second information indicating that the MMTP packet was generated in leap seconds, the restoration unit 36 is based on the time information input by the count unit 35 when the in-insertion information is input. At the timing, the MMTP packet is restored.

According to the present embodiment, the receiving device 30 can restore each MMTP packet at an appropriate timing even when leap seconds are inserted.

The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

This application claims priority based on Japanese Patent Application No. 2016-240867 filed on Dec. 13, 2016, the entire disclosure of which is incorporated herein.

30, 300 Receiving device 35 Count unit 36 Restoring unit 51 Time monitoring unit 100 Information communication system 200 Transmitting device 210, 340 Clock signal generation unit 220, 350 NTP counter unit 221 Transmission side leap second monitoring unit 230 MMTP packetization processing unit 240 NTP Packet generation unit 250 Multiplexing unit 310 Demultiplexing unit 320 NTP packet receiving unit 330 Comparison unit 351 Receiving side leap second monitoring unit 360 MMTP packet restoration unit

Claims (6)

Restoring means for restoring data from the MMTP packet sent by the sending device;
Time monitoring means for inputting into-restoration information indicating that the leap second is being inserted when the leap second is the time inserted to approximate the coordinated universal time;
Installed on the broadcast receiving side with a counting means for inputting time information indicating the current time based on the Coordinated Universal Time to the restoration means,
The MMTP packet includes leap second information indicating that it was generated in the leap second when generated at a timing corresponding to the leap second,
When the MMTP packet includes leap second information indicating that it has been generated in the leap second, the restoration means includes the time information input by the counting means when the in-insertion information is input. The receiving apparatus, wherein the MMTP packet is restored at a timing based on The MMTP packet includes time stamp information indicating a time according to the timing at which the MMTP packet is generated,
When the MMTP packet includes leap second information indicating that it has been generated in the leap second, the restoration means includes the time information input by the counting means when the in-insertion information is input. The receiving apparatus according to claim 1, wherein the MMTP packet is restored at a timing based on a time indicated by the time indicated by the time indicated by the time stamp information. The MMTP packet includes time stamp information indicating a time according to the timing at which the MMTP packet is generated,
The restoration means is input by the counting means when the in-insertion information is not input when the MMTP packet includes leap second information indicating that it was generated when the leap second is not The receiving apparatus according to claim 1 or 2, wherein the MMTP packet is restored at a timing based on a time indicated by time information and a time indicated by the time stamp information. The NTP packet transmitted by the transmission device together with the MMTP packet includes NTP time information indicating the time when the MMTP packet was generated based on the Coordinated Universal Time,
The receiving device according to any one of claims 1 to 3, wherein the time monitoring unit determines whether the current time is leap second based on a time indicated by the NTP time information. The receiving device according to claim 1, wherein the receiving device is connected to the transmitting device via a communication network. The receiving device according to any one of claims 1 to 5,
A communication system comprising the transmission device.

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