JP2021005880A - Reception device and communication system - Google Patents

Abstract

To provide a reception device that can restore each MMTP packet in an appropriate order even when a leap second is inserted.SOLUTION: A restoration unit 36 restores data from an MMTP packet transmitted by a transmission device. During a leap second which is a time to be inserted so as to approach the Coordinated Universal Time to the world time, a time monitoring unit 51 inputs, to the restoration unit 36, under-insertion information indicating that the time is the leap second. A count unit 35 inputs time information indicating the current time into the restoration unit 36 based on the Coordinated Universal Time. When an MMTP packet is generated at a timing corresponding to the leap second, leap second information indicating that the MMTP packet has been generated during the leap second is contained in the MMTP packet. In a case where the MMTP packet contains the leap second information indicating that the MMTP packet has been generated during the leap second, the restoration unit 36 restores the MMTP packet at a timing based on the time information input by the count unit 35 when the under-insertion information is input.SELECTED DRAWING: Figure 5

Description

The present invention relates to a receiving device for communicating MMTP packets and a communication system.

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

Non-Patent Document 1 describes a system for transmitting and receiving more information via broadcasting and communication lines.

In the system described in Non-Patent Document 1, information is generated according to the date and time of reproduction so that the receiving device can reproduce in an appropriate order based on the time stamp of NTP (Network Time Protocol). It is transmitted in association with television program information and the like. Here, the NTP time stamp means information indicating the date and time based on the NTP by the integrated number of seconds from the predetermined date and time. Hereinafter, for the sake of simplicity, the date and time are also simply referred to as time. The receiving device reproduces the video and audio based on the television program information and the like in an appropriate order based on the separately acquired NTP time stamp and the time information associated with the television program information and the like.

The NTP time stamp is based on Coordinated Universal Time. Coordinated Universal Time is adjusted once every few years to approach Coordinated Universal Time. The adjustment is made by inserting a leap second or deleting a leap second. Specifically, when a leap second is inserted, for example, a series of 8:59:59:00 (hereinafter referred to as "8:59:59: 00") to 8:59:59:99. Timestamps are generated twice in a row. When the leap second is deleted, a time stamp indicating the second after 8:59:58: 00 is generated so as to indicate 9:00:00: 00.

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

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

Japanese Unexamined Patent Publication No. 2016-100892

"Media transport method by MMT in digital broadcasting 1.7 version", [online], July 2016, Association of Radio Industries and Businesses, [Search 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. Then, each MMTP packet is restored on the receiving side at a timing corresponding to the value indicated in the Timestamp field in the MMTP packet header.

FIG. 6 is an explanatory diagram showing an example of a timing at which an MMTP packet is generated and a timing at which it is restored. In FIG. 6, the timing at which the transmitting device generates the MMTP packet is shown in the middle stage. Further, in FIG. 6, the lower part shows the timing at which the transmitting device performs a restoration process on the MMTP packet to restore the main signal data (hereinafter, also simply referred to as restoring the MMTP packet).

As shown in FIG. 6, the transmission device includes the main signal data in the payload according to the order in which the main signal data is input, and time stamp information indicating the time according to the timing when the main signal data is input. MMTP packets containing the above in the header 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 packet is generated. Specifically, the MMTP packet (MMTP packet numbered with (8) in FIG. 6) including the time stamp information indicating 8:59:59:200 generated when the quiet second is inserted is 8 MMTP packet containing time stamp information indicating: 59: 59: 300 (MMTP packet numbered (5) in FIG. 6), MMTP packet containing time stamp information indicating 8:59:59: 500 (FIG. 6). MMTP packet numbered (6) in (6) and MMTP packet (MMTP packet numbered (7) in FIG. 6) containing time stamp information indicating 8:59:59:800. ing. Further, the MMTP packet (MMTP packet numbered (9) in FIG. 6) including the time stamp information indicating 8:59:59: 600 generated when the leap second is inserted is 8:59: It is generated after the MMTP packet (MMTP packet numbered (7) in FIG. 6) containing the time stamp information indicating 59: 800.

That is, as shown in FIG. 6, each MMTP packet generated in the period A, which is one second immediately before the leap second, and numbered (5) to (7) is in the period of the inserted leap second. It is generated before each MMTP packet generated in a certain 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 the smaller values are numbered.

However, when the restoration process is performed on the MMTP packets at the timing corresponding to the time 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 corresponding to the value indicated in the Timestamp field in the MMTP packet header. In this case, there is a problem that each MMTP packet is not restored in an appropriate order and timing.

Specifically, as shown in the lower part of FIG. 6, the restoration process is performed on the MMTP packet numbered (8) before the MMTP packet numbered (5) to (7). .. Then, the main signal data based on the MMTP packet numbered (8) is restored before the main signal data based on the MMTP packet numbered (5) to (7). Further, as shown in the lower part of FIG. 6, the restoration process is performed on the MMTP packet numbered (9) 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 the video and audio based on the television program information and the like are not reproduced in an appropriate order.

Further, in the invention described in Patent Document 1, the restoration order of MPU is examined, but the restoration order of MMTP packets is not considered.

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

The receiving device according to the present invention is a leap second when it is a recovery means that restores data from an MMTP packet transmitted by a transmitting device and a leap second, which is the time inserted to bring Coordinated Universal Time closer to Universal Time. It is installed on the broadcast receiving side with a time monitoring means for inputting insertion information indicating that to the restoration means and a counting means for inputting the time information indicating the current time to the restoration means based on Coordinated Universal Time, and is included in the MMTP packet. Includes leap second information indicating that it was generated in leap seconds when it was generated at a timing corresponding to the leap second, and the recovery means is the leap second information indicating that it was generated in leap seconds 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 insertion information is input.

The communication system according to the present invention is characterized by comprising a receiving device of any aspect and a transmitting device of any aspect.

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 1st Embodiment of this invention. It is explanatory drawing which shows the example of the restoration process which restores the main signal data in the MMTP packet restoration part. It is a flowchart which shows the operation of the transmission device in 1st Embodiment of this invention. It is a flowchart which shows the operation of the receiving apparatus in 1st Embodiment of this invention. It is a block diagram which shows the structural example of the receiving apparatus of 2nd Embodiment. It is explanatory drawing which shows the example of the timing which MMTP packet is generated and the timing which is restored.

Embodiment 1.
The information communication system 100 of the first embodiment will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of the information communication system 100 of the first embodiment. As shown in FIG. 1, the information communication system 100 of the first embodiment includes a transmitting device 200 and a receiving device 300. The transmitting device 200 and the receiving device 300 are connected to, for example, a communication network 400 such as the Internet. Then, the transmitting device 200 and the receiving device 300 transmit and receive information to and from each other via the communication network 400.

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

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

A configuration example of the transmission device 200 will be described. As shown in FIG. 1, the transmission device 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 or 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 generator 210, a frequency is, for ^{example, 2} 32 Hz clock signal and ^generates a clock signal of ^{2 24} ~2 28 Hz.

The clock signal input by the clock signal generation unit 210 and the external time information transmitted from the external server are input to the NTP counter unit 220. The external time information transmitted from the external server is, for example, an NTP format signal transmitted from the NTP server, and is a signal indicating at least 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, if a leap second is inserted in the last minute of the current month, the leap second indicator is set to the value "1", otherwise the leap second indicator is set to the value "0". 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, the NTP counter unit 220 generates NTP time information indicating the current date and time (also simply referred to as time for the sake of simplicity) based on the NTP format, for example, by accumulating seconds from a predetermined date and time. .. It is assumed that the NTP time information includes the leap second indicator shown in the input external time information. Therefore, the time indicated by the NTP time information is the 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. The 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.

Further, 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 monitoring unit 221 on the transmitting side. including.

When the transmitting side leap second monitoring unit 221 determines that the time indicated by the NTP time information is the time in the leap second, the MMTP packetization processing unit 230 converts the leap second inserting information indicating that the leap second is inserted. Enter in.

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

The MMTP packetization processing unit 230 includes time stamp information indicating a time corresponding to the time indicated by the NTP time information input by the NTP counter unit 220 and leap second information in a header, and uses the input main signal data as a payload. Generate an MMTP packet containing. The MMTP packetization processing unit 230 generates an MMTP packet in the header containing leap second information indicating that it was generated in leap seconds when the transmitting side leap second monitoring unit 221 inputs information during leap second insertion. To do. Further, the MMTP packetization processing unit 230 includes leap second information indicating that it was generated when it was not a leap second in the header when the transmitting side leap second monitoring unit 221 did not input the leap second inserting 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 indicates that the MMTP packet was generated in the leap second when the value of the flag is set to "1". When the value of the flag is set to "0", it indicates that the MMTP packet was generated when it was not a leap second.

The MMTP packetization processing unit 230 generates time stamp information indicating a time in consideration of the time required for decoding the main signal data and the like at the time indicated by the NTP time information input by the NTP counter unit 220.

Here, when the leap second is inserted, for example, 8:59:59: 000 to 8:59:59:999 is repeated twice. Therefore, for example, a series of NTP time information indicating 8:59:59: 000 to 8:59:59:999 is continuously input to the MMTP packetization processing unit 230 twice. Then, among the NTP time information generated twice in succession, the NTP time information indicating 8:59:59: 000 to 8:59:59:999 is input to the MMTP packetization processing unit 230. If so, the information during leap second insertion is entered.

Therefore, the MMTP packetization processing unit 230 includes time stamp information indicating the time corresponding to the time indicated by the NTP time information and leap second information indicating that the information was generated in the leap second when the information during the leap second insertion was input. Generates an MMTP packet containing and in the header. That is, in the MMTP packetization processing unit 230, when a leap second is inserted and, for example, 8:59:59: 000 to 8:59:59:999 is repeated twice, the second time is 8:59:59. At the timing when: 000 to 8:59:59:999 arrives, the header includes time stamp information indicating the time corresponding to the time indicated by the NTP time information and leap second information indicating that the data was generated in leap seconds. Generates an MMTP packet containing the input main signal data in the payload. Therefore, two sets of MMTP packets including the time stamp information indicating the time corresponding to the time indicated by the NTP time information indicating 8:59:59: 00 to 8:59:59:99 in the header are generated, and one set of MMTP packets is generated. The header of each MMTP packet contains leap second information indicating that it was generated in leap seconds, and the header of the other set of MMTP packets contains leap seconds indicating that it was generated when it was not in 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, the NTP packet generation unit 240 generates, for example, an NTP packet including NTP time information indicating the time when 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, the multiplexing unit 250 transmits the generated IP packet to the receiving device 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 shown in FIG. 1, the receiving device 300 includes a multiplexing 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 multiplex separation unit 310, the NTP packet reception unit 320, the comparison unit 330, the clock signal generation unit 340, the NTP counter unit 350, and the MMTP packet restoration unit 360 are, for example, a CPU or a plurality of CPUs that execute processing according to program control. Realized by the circuit.

When the multiplex separation unit 310 receives an IP packet in which an MMTP packet and an NTP packet are multiplexed and transmitted, the multiplex separation unit 310 multiplexes the IP packet into an NTP packet and an MMTP packet. Then, the multiplex separation unit 310 inputs the multiplex separated 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, which 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.

A PLL (Phase Locked Loop) is configured by the comparison unit 330 and the clock signal generation unit 340. 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 which 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 according 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. The clock signal generator 340, in response to a signal comparison unit 330 is input, frequency, ^{e.g., 2} 32 Hz clock signal and ^generates a clock signal of ^{2 24} ~2 28 Hz.

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, for example, generated NTP time information indicating the current date and time (also simply referred to as time for the sake of simplicity) based on the accumulated seconds from a predetermined date and time 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.

Further, as shown in FIG. 1, the NTP counter unit 350 is a receiving side leap second monitoring unit that determines whether or not the time indicated by the generated NTP time information generated by the NTP counter unit 350 is the time in leap seconds. Includes 351.

When the receiving side leap second monitoring unit 351 determines that the time indicated by the generated NTP time information is the time in the leap second, the leap second inserting information indicating that the leap second is inserted is the MMTP packet restoration unit 360. Enter in.

When the receiving side leap second monitoring unit 351 indicates that a leap second is inserted by a 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 insertion 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 restoration processing for restoring the main signal data from the MMTP packet at the 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 the MMTP including the time stamp information at a timing corresponding to, for example, 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. Performs a restoration process that restores the main signal data from the packet. More specifically, the MMTP packet restoration unit 360 includes the time stamp information at a timing at which 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 match, for example. Performs restoration processing to restore the main signal data from the MMTP packet.

When a leap second is inserted, the time stamp information may indicate the same time in different MMTP packets.

Specifically, when a leap second is inserted, the MMTP packet restoration unit 360 contains 2 MMTP packets including time stamp information indicating, for example, 8:59:59: 000 to 8:59:59:999. The set is input. Then, of the two sets of MMTP packets, one set of MMTP packets generated at the timing when the second 8:59:59: 000 to 8:59:59:999 arrives is generated in leap seconds. It contains leap second information indicating that it 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 insertion information indicating that the leap second is inserted, which is input from the receiving side leap second monitoring unit 351, and one of the sets thereof. Restoration processing is performed to restore the main signal data from the MMTP packet containing 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 information indicating that the leap second is inserted, which is input from the receiving side leap second monitoring unit 351 for example. Restoration that restores the main signal data from the MMTP packet containing the time stamp information at the timing when the time indicated by the generated NTP time information and the time indicated by the time stamp information included in the one set of MMTP packets match. Perform processing.

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

FIG. 2 is an explanatory diagram showing an example of a restoration process for restoring 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 the time when the MMTP packet is generated, but the time when the generation of the MMTP packet is finished may be the time when the MMTP packet is generated. Other timings such as the timing at which the main signal data coding process ends 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 packet is generated. Specifically, the MMTP packet (MMTP packet numbered (8) in FIG. 2) including the time stamp information indicating 8:59:59:200 generated when the quiet second is inserted is 8 MMTP packet containing time stamp information indicating: 59: 59: 300 (MMTP packet numbered with (5) in FIG. 2), MMTP packet containing time stamp information indicating 8:59:59:500 (FIG. 2). MMTP packet numbered (6) in (6) and MMTP packet (MMTP packet numbered (7) in FIG. 2) containing time stamp information indicating 8:59:59:800. ing. Further, the MMTP packet (MMTP packet numbered (9) in FIG. 2) including the time stamp information indicating 8:59:59: 600 generated when the leap second is inserted is 8:59: It is generated after the MMTP packet (MMTP packet numbered (7) in FIG. 2) containing the time stamp information indicating 59: 800.

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

Further, each MMTP packet numbered (8) to (10) is generated in a leap second based on the leap second information of each MMTP packet generated in the period B and numbered (8) to (10). It is shown that it was done. When each MMTP packet numbered (5) to (7) is not a leap second according to the leap second information of each MMTP packet generated in the period A and numbered (5) to (7). It is shown that it was generated in.

Therefore, the MMTP packet restoration unit 360 transmits an MMTP packet including leap second information indicating that it was generated in leap seconds from the NTP counter unit 350 together with information during leap second insertion indicating that it was generated in leap seconds. Restore at the 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 packet numbered (1) to (7) and (11) to (13) was generated when it was not a leap second. It is included. Further, in the example shown in FIG. 2, the MMTP packets numbered (8) to (10) include leap second information indicating that they were generated in leap seconds.

Therefore, the MMTP packet restoration unit 360 is inserting the MMTP packet numbered (1) to (7), (11) to (13) with the time indicated by the time stamp information included in the MMTP packet and the leap second. Restoration processing is performed to restore the main signal data from the MMTP packet containing the time stamp information at the timing when the time indicated by the generated NTP time information input by the NTP counter unit 220 when the information is not input matches. Further, 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 matches, the 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 each MMTP packet 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 showing the operation of the transmission device 200 according to the first embodiment. As shown in FIG. 3, in the transmission device 200, the clock signal generation unit 210 generates a clock signal having a predetermined frequency and inputs it 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 transmitting side leap second monitoring unit 221 determines that the time indicated by the NTP time information is the time in the leap second (Y in step S104), 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 the header the time stamp information indicating the time indicated by the NTP time information input by the NTP counter unit 220 and the leap second information according to whether or not the leap second insertion information is input. , Generates an MMTP packet containing the input main signal data in the payload (step S106).

Further, 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, the multiplexing unit 250 transmits the generated IP packet to the receiving device 300.

Next, the operation of the receiving device 300 in the first embodiment will be described. FIG. 4 is a flowchart showing the operation of the receiving device 300 according to the first embodiment. As shown in FIG. 4, in the receiving device 300, when the multiplex separation unit 310 receives an IP packet in which an MMTP packet and an NTP packet are multiplexed and transmitted, the IP packet is divided into an NTP packet and an MMTP packet. (Step S201). Then, the multiplex separation unit 310 inputs the multiplex separated 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 (step S202).

The comparison unit 330 compares the time indicated by the restored NTP time information, which is the restored NTP time information, with the time indicated by the generated NTP time information, which 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 according 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.

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

When the receiving side leap second monitoring unit 351 determines that the time indicated by the generated NTP time information is the time in the leap second (Y in step S206), the leap second inserting information indicating that the leap second is inserted. Is input to the MMTP packet restoration unit 360 (step S207).

The MMTP packet recovery unit 360 generated the MMTP packet in leap seconds when the input MMTP packet contained leap second information indicating that it was generated in leap seconds (Y in step S208). Restoration is performed 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 information indicating that (step S209).

Further, when the input MMTP packet contains leap second information indicating that the MMTP packet was generated when the MMTP packet is not in leap seconds (N in step S208), the MMTP packet recovery unit 360 sets the MMTP packet in leap seconds. 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 insertion information is not input (step S210).

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

According to the present embodiment, in the case of leap seconds, the MMTP packetization processing unit 230 generates an MMTP packet including leap second information indicating that it is a leap second. Then, the multiplexing unit 250 multiplexes the generated MMTP packet and the NTP packet according to the current time and transmits it to the receiving device 300.

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

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

Embodiment 2.
Next, the receiving device 30 of the second embodiment will be described with reference to the drawings. FIG. 5 is a block diagram showing a configuration example of the receiving device 30 of the second embodiment. As shown in FIG. 5, the receiving device 30 of the second embodiment includes the restoring unit 36, the time monitoring unit 51, and the 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. Further, the time monitoring unit 51 corresponds to, for example, the receiving side leap second monitoring unit 351 in the first embodiment shown in FIG. The counting 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 to the restoration unit 36 the insertion information indicating that the time is a leap second, which is the time inserted to bring the coordinated universal time closer to the world time.

The counting unit 35 inputs time information indicating the current time based on Coordinated Universal Time into the restoration unit 36.

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

Then, the restoration unit 36 is based on the time information input by the counting unit 35 when the insertion information is input when the leap second information indicating that the MMTP packet was generated in leap seconds is included in the MMTP packet. Restore the MMTP packet at the timing.

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

Although the present invention has been described above with reference to the embodiments, 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 within the scope of the present invention in terms of the structure and details of the present invention.

This application claims priority on the basis of Japanese application Japanese Patent Application No. 2016-240867 filed on December 13, 2016, and incorporates all of its disclosures herein.

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

Claims (10)

MMTP packet restoration means for restoring MMTP packets and
Time information generation means for generating time information and
A determining means for determining whether or not the time indicated by the time information generated by the time information generating means is a leap second.
When the determination means determines that the time is in leap seconds, the input means for inputting the leap second insertion information indicating that the leap second is inserted into the MMTP packet restoration means.
With
The MMTP packet restoration means is the time information generating means when the leap second inserting information is input by the input means when the leap second information indicating that the MMTP packet is generated in the leap second is included in the MMTP packet. A receiving device characterized in that the MMTP packet is restored at a timing based on the time indicated by the time information generated by. The MMTP packet restoration means is the time information generating means when the MMTP packet does not include leap second information indicating that the MMTP packet was generated in leap seconds and the information during leap second insertion is not input by the input means. The receiving device according to claim 1, wherein the MMTP packet is restored at a timing based on the time indicated by the time information generated by. The MMTP packet includes time stamp information indicating a time corresponding to the timing at which the MMTP packet is generated.
The MMTP packet restoration means is generated by the time information generation means when the leap second insertion information is input when the MMTP packet contains leap second information indicating that the MMTP packet was generated in leap seconds. The receiving device according to claim 1 or 2, wherein the MMTP packet is restored at a timing based on the time indicated by the time information and the time indicated by the time stamp information. The MMTP packet includes time stamp information indicating a time corresponding to the timing at which the MMTP packet is generated.
When the MMTP packet restoration means does not include leap second information indicating that the MMTP packet was generated in leap seconds, and the information during leap second insertion is not input, the time information generating means The receiving device according to any one of claims 1 to 3, which restores the MMTP packet at a timing based on the time indicated by the generated time information and the time indicated by the time stamp information. MMTP packet generation means for generating MMTP packets and
Time information generation means for generating time information and
A determining means for determining whether or not the time indicated by the time information generated by the time information generating means is a leap second.
When the determination means determines that the time is in leap seconds, the input means for inputting the leap second insertion information indicating that the leap second is inserted into the MMTP packet generation means.
With
When the leap second insertion information is input by the input means, a time stamp indicating a time corresponding to the time information generated by the time information generating means is added to the MMTP packet generated by the MMTP packet generating means. A transmitter characterized by containing information and leap second information indicating that it was generated in leap seconds. The receiving device according to any one of claims 1 to 4,
A communication system including the transmission device according to claim 5. Generate time information,
Determines whether the time indicated by the generated time information is the time in leap seconds.
When it is determined by the above determination that the time is in leap seconds, information during leap second insertion indicating that leap seconds are inserted is generated.
When the MMTP packet contains leap second information indicating that it was generated in leap seconds, the MMTP packet is sent at a timing based on the time indicated by the time information generated when the leap second insertion information is generated. A receiving method characterized by restoring. Generate time information,
Determines whether the time indicated by the generated time information is the time in leap seconds.
When it is determined in the above determination that the time is in leap seconds, information during leap second insertion indicating that leap seconds are inserted is generated.
When the leap second insertion information is generated, an MMTP packet including time stamp information indicating the time corresponding to the generated time information and leap second information indicating that the leap second is generated is displayed. A transmission method characterized by generating. On the computer
MMTP packet restoration processing to restore MMTP packets and
Time information generation process to generate time information and
Judgment processing to determine whether the time indicated by the generated time information is the time in leap seconds, and
When it is determined by the determination process that the time is in leap seconds, a generation process for generating leap second inserting information indicating that leap seconds are inserted is executed.
When the MMTP packet restoration process includes leap second information indicating that the MMTP packet was generated in leap seconds, the time information generated when the leap second insertion information is generated in the generation process. A receiving program for restoring the MMTP packet at a timing based on the time indicated by. On the computer
MMTP packet generation processing to generate MMTP packets and
Time information generation process to generate time information and
Judgment processing to determine whether the time indicated by the generated time information is the time in leap seconds, and
When it is determined in the determination process that the time is in leap seconds, a generation process for generating leap second inserting information indicating that leap seconds are inserted is executed.
When the leap second insertion information is generated in the generation process in the MMTP packet generation process, the time stamp information indicating the time corresponding to the generated time information and the leap second indicating that the information is generated in the leap second are generated. A transmission program for generating MMTP packets containing second information.

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