Transmitting system, multiplexing apparatus, and leap second correction method

Patent metadata

Field	Value
Publication number	US-2017373779-A1
Application number	US-201715700397-A
Country	US
Kind code	A1
Filing date	Sep 11, 2017
Priority date	Mar 11, 2015
Publication date	Dec 28, 2017
Grant date	—

Abstract

A transmitting system includes an outputting apparatus and a multiplexing apparatus. The outputting apparatus transmits MMTP packets to which an NTP short format timestamp is added. The multiplexing apparatus multiplexes the MMTP packets. The multiplexing apparatus includes an extractor, a controller, a determiner, a management information generator, a continuity determiner, and a transmission timing adjuster. The transmission timing adjuster writes, for adjustment of a transmission timing of an MMTP packet being close to an MMTP packet in which an NTP short format timestamp value is discontinuous, time information taking a leap second processing into consideration, to the NTP short format timestamp of the MMTP packet.

First claim

1 . A transmitting system comprising an outputting apparatus configured to transmit MPEG Media Transport Protocol (MMTP) packets to which a Network Time Protocol (NTP) short format timestamp is added, and a multiplexing apparatus configured to multiplex the MMTP packets, wherein
the multiplexing apparatus comprises: an extractor configured to extract first integer second time information from the NTP short format timestamp added to an MMTP packet transmitted from the outputting apparatus; a controller configured to acquire information relating to a leap second processing and second integer second time information corresponding to a discontinuity occurrence time that occurred due to leap second correction, based on information concerning a leap second included in an NTP packet and time information acquired based on an NTP; a determiner configured to determine whether the first integer second time information matches the second integer second time information; a management information generator configured to generate, in response to a determination that the first integer second time information matches the second integer second time information, matching information indicating the match and identification information relating to the leap second processing; a continuity determiner configured to determine whether the MMTP packet is close to an MMTP packet in which an NTP short format timestamp value is discontinuous, based on the matching information, the identification information, and a difference between a value of the NTP short format timestamp and the time information acquired based on the NTP; and a transmission timing adjuster configured to adjust a transmission timing of a MMTP packet transmitted from the outputting apparatus, wherein the transmission timing adjuster writes, for adjustment of a transmission timing of the MMTP packet being close to the MMTP packet in which the NTP short format timestamp value is discontinuous, time information taking the leap second processing into consideration, to the NTP short format timestamp of the MMTP packet.

2 . The system according to claim 1 ,
wherein the multiplexing apparatus further comprises an input selector configured to receive a plurality of MMTP packets, select an MMTP packet having a smallest value of an NTP short format timestamp, and output the selected MMTP packet to the extractor.

3 . The system according to claim 1 , wherein the transmission timing adjuster outputs the MMTP packet having the NTP short format timestamp in which the time information is written, in accordance with the time information.

4 . The system according to claim 1 , wherein if the leap second processing is insertion of a leap second, the transmission timing adjuster determines whether a time when the MMTP packet close to the MMTP packet in which the NTP short format timestamp value is discontinuous is transmitted exceeds 00:00:00, and writes, if the time exceeds 00:00:00, time information indicating a value obtained by subtracting one second from the excess time.

5 . The system according to claim 1 , wherein if the leap second processing is deletion of a leap second, the transmission timing adjuster determines whether a time when the MMTP packet close to the MMTP packet in which the NTP short format timestamp value is discontinuous is transmitted exceeds 23:59:59, and writes, if the time exceeds 23:59:59, time information indicating a value obtained by adding one second to the excess time.

6 . A multiplexing apparatus comprising:
an extractor configured to extract first integer second time information from a Network Time Protocol (NTP) short format timestamp added to an MPEG Media Transport Protocol (MMTP) packet; a controller configured to acquire information relating to a leap second processing and second integer second time information corresponding to a discontinuity occurrence time that occurred due to leap second correction, based on information concerning a leap second included in an NTP packet and time information acquired based on an NTP; a determiner configured to determine whether the first integer second time information matches the second integer second time information; a management information generator configured to generate, in response to a determination that the first integer second time information matches the second integer second time information, matching information indicating the match and identification information relating to the leap second processing; a continuity determiner configured to determine whether the MMTP packet is close to an MMTP packet in which an NTP short format timestamp value is discontinuous, based on the matching information, the identification information, and a difference between a value of the NTP short format timestamp and the time information acquired based on the NTP; and a transmission timing adjuster configured to adjust a transmission timing of a MMTP packet, wherein the transmission timing adjuster writes, for adjustment of a transmission timing of the MMTP packet being close to the MMTP packet in which the NTP short format timestamp value is discontinuous, time information taking the leap second processing into consideration, to the NTP short format timestamp of the MMTP packet.

7 . The apparatus according to claim 6 , further comprising:
an input selector configured to receive a plurality of MMTP packets, select an MMTP packet having a smallest value of an NTP short format timestamp, and output the selected MMTP packet to the extractor.

8 . The apparatus according to claim 6 , wherein the transmission timing adjuster outputs the MMTP packet having the NTP short format timestamp in which the time information is written, in accordance with the time information.

9 . The apparatus according to claim 6 , wherein if the leap second processing is insertion of a leap second, the transmission timing adjuster determines whether a time when the MMTP packet close to the MMTP packet in which the NTP short format timestamp value is discontinuous is transmitted exceeds 00:00:00, and writes, if the time exceeds 00:00:00, time information indicating a value obtained by subtracting one second from the excess time.

10 . The apparatus according to claim 6 , wherein if the leap second processing is deletion of a leap second, the transmission timing adjuster determines whether a time when the MMTP packet close to the MMTP packet in which the NTP short format timestamp value is discontinuous is transmitted exceeds 23:59:59, and writes, if the time exceeds 23:59:59, time information indicating a value obtained by adding one second to the excess time.

11 . A leap second correction method, comprising:
extracting first integer second time information from a Network Time Protocol (NTP) short format timestamp added to an MPEG Media Transport Protocol (MMTP) packet; acquiring information relating to a leap second processing and second integer second time information corresponding to a discontinuity occurrence time occurred due to leap second correction, based on information concerning a leap second included in an NTP packet and time information acquired based on an NTP; determining whether the first integer second time information matches the second integer second time information; generating, in response to a determination that the first integer second time information matches the second integer second time information, matching information indicating the match and identification information relating to the leap second processing; determining whether the MMTP packet is close to an MMTP packet in which an NTP short format timestamp value is discontinuous, based on the matching information, the identification information,

Assignees

• Toshiba Kk
• Toshiba Infrastructure Systems & Solutions Corp

Inventors

• Yamakage Tomoo
• Tanaka Tatsuya
• Hashi Yasumichi
• Iwami Keita

Classifications

• H04J3/0661 Primary

  using timestamps · CPC title

• H04N21/242 Primary

  Synchronisation processes, e.g. processing of PCR [Programme Clock References] {(arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18)} · CPC title

• H04J3/0685

  Clock or time synchronisation in a node; Intranode synchronisation · CPC title

• H04J3/0632

  Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] (queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56) · CPC title

• H04L65/65

  Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP] · CPC title