WO2015040817A1 - Procédé d'émission, procédé de réception, appareil émetteur et appareil récepteur - Google Patents

Procédé d'émission, procédé de réception, appareil émetteur et appareil récepteur Download PDF

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Publication number
WO2015040817A1
WO2015040817A1 PCT/JP2014/004591 JP2014004591W WO2015040817A1 WO 2015040817 A1 WO2015040817 A1 WO 2015040817A1 JP 2014004591 W JP2014004591 W JP 2014004591W WO 2015040817 A1 WO2015040817 A1 WO 2015040817A1
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WIPO (PCT)
Prior art keywords
transmission
reference clock
clock information
packet
stored
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Application number
PCT/JP2014/004591
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English (en)
Japanese (ja)
Inventor
賀敬 井口
遠間　正真
加藤　久也
Original Assignee
パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカ
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Priority claimed from JP2014173071A external-priority patent/JP6382029B2/ja
Application filed by パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカ filed Critical パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカ
Priority to EP20175768.9A priority Critical patent/EP3758388A1/fr
Priority to EP14845940.7A priority patent/EP3048793B1/fr
Priority to CN201480040274.1A priority patent/CN105379290B/zh
Publication of WO2015040817A1 publication Critical patent/WO2015040817A1/fr
Priority to US15/063,602 priority patent/US10070199B2/en
Priority to US16/047,642 priority patent/US11082750B2/en
Priority to US17/361,488 priority patent/US20210345008A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/60—Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
    • H04N21/63—Control signaling related to video distribution between client, server and network components; Network processes for video distribution between server and clients or between remote clients, e.g. transmitting basic layer and enhancement layers over different transmission paths, setting up a peer-to-peer communication via Internet between remote STB's; Communication protocols; Addressing
    • H04N21/643—Communication protocols
    • H04N21/64322—IP
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
    • H04N21/85—Assembly of content; Generation of multimedia applications
    • H04N21/854—Content authoring
    • H04N21/8547—Content authoring involving timestamps for synchronizing content

Definitions

  • the present disclosure relates to a transmission method and a reception method in a case where content is transmitted through broadcasting using an IP (Internet Protocol) packet.
  • IP Internet Protocol
  • the MMT method (see Non-Patent Document 1) is a multiplexing method for multiplexing and packetizing content such as video and audio and transmitting the content through one or more transmission paths such as broadcasting or communication.
  • the MMT method is applied to a broadcasting system, the reference clock information on the transmission side is transmitted to the reception side, and the reception device generates a system clock in the reception device based on the reference clock information.
  • MPEG media transport MMT
  • a transmission method is a transmission method in content transmission using an IP (Internet Protocol) packet performed through broadcasting, and stores one or more first transmission units in which the IP packet is stored.
  • the first second in the frame Reference clock information indicating the time for reproducing the content is included in the first transmission unit located at the head of the transmission unit.
  • a recording medium such as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable CD-ROM.
  • a recording medium such as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable CD-ROM.
  • These comprehensive or specific aspects may be realized by any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.
  • FIG. 1 is a protocol stack diagram when transmission is performed using the MMT scheme and the advanced BS transmission scheme.
  • FIG. 2 is a diagram illustrating a data structure of a TLV packet.
  • FIG. 3 is a block diagram showing a basic configuration of the receiving apparatus.
  • FIG. 4 is a block diagram showing a functional configuration of the receiving apparatus when the reference clock information is stored in the extension field of the MMT packet header.
  • FIG. 5 is a diagram illustrating a flow of obtaining reference clock information of the receiving apparatus when the reference clock information is stored in the extension field of the MMT packet header.
  • FIG. 6 is a block diagram illustrating a functional configuration of the receiving device when the reference clock information is stored in the control information.
  • FIG. 1 is a protocol stack diagram when transmission is performed using the MMT scheme and the advanced BS transmission scheme.
  • FIG. 2 is a diagram illustrating a data structure of a TLV packet.
  • FIG. 3 is a block diagram showing a basic configuration of the receiving apparatus.
  • FIG. 4
  • FIG. 7 is a diagram illustrating an acquisition flow of the reference clock information of the receiving device when the reference clock information is stored in the control information.
  • FIG. 8 is a block diagram showing a configuration of a receiving apparatus when reference clock information is stored in a TLV packet.
  • FIG. 9 is a diagram illustrating an example in which the long format NTP is stored in the TLV packet.
  • FIG. 10 is a diagram illustrating an acquisition flow of the reference clock information of the receiving device when the reference clock information is stored in the TLV packet.
  • FIG. 11 is a diagram illustrating a configuration in which the reference clock information is added immediately before the header of the IP packet.
  • FIG. 12 is a diagram illustrating a configuration in which the reference clock information is added immediately before the TLV packet.
  • FIG. 13 is a diagram illustrating a configuration of a transmission slot.
  • FIG. 14 is a diagram illustrating a configuration of a slot header of a transmission slot.
  • FIG. 15 is a block diagram illustrating a functional configuration of the receiving apparatus when information indicating that the reference clock information is included in the slot header is stored in the TMCC control information.
  • FIG. 16 is a diagram showing an acquisition flow of the reference clock information when information indicating that the reference clock information is included in the slot header is stored in the TMCC control information.
  • FIG. 17 is a diagram showing a flow when a bit string at a specific position is extracted from an IP packet or a compressed IP packet.
  • FIG. 18 is a block diagram illustrating a functional configuration of the transmission apparatus.
  • FIG. 19 is a diagram illustrating an operation flow of the transmission apparatus.
  • the present disclosure relates to a hybrid distribution system that uses an MMT (MPEG Media Transport) method being standardized by MPEG (Moving Picture Expert Group), transmits reference clock information from a transmission side, and receives reference clock information on a reception side.
  • MMT MPEG Media Transport
  • the present invention relates to a method and an apparatus for generating (reproducing) a reference clock.
  • the MMT method is a multiplexing method for multiplexing and packetizing video and audio and transmitting them through one or more transmission paths such as broadcasting or communication.
  • the reference clock on the transmission side is synchronized with NTP (Network Time Protocol) defined in IETF RFC 5905, and based on the reference clock, PTS (Presentation Time Stamp) or DTS (Decode) Give the media a time stamp such as Time Stamp.
  • NTP Network Time Protocol
  • PTS Presentation Time Stamp
  • DTS Decode
  • the reference clock information on the transmission side is transmitted to the reception side, and the reception device generates a reference clock (hereinafter also referred to as a system clock) in the reception device based on the reference clock information.
  • control information such as a message, a table, or a descriptor
  • MMT packet header added.
  • the MMT packet is transmitted through a broadcast transmission path or a communication transmission path by being stored in an IP packet.
  • the MMT packet When transmitting an MMT packet using the advanced BS transmission system defined by the ARIB standard, the MMT packet is encapsulated into an IP packet, the IP packet is encapsulated into a TLV (Type Length Value) packet, and then the advanced BS transmission system is used. Store in the specified transmission slot.
  • TLV Type Length Value
  • the TLV packet is extracted from the transmission slot
  • the IP packet is extracted from the TLV packet
  • the IP packet is extracted from the TLV packet
  • the IP packet Multiple processes such as extracting the MMT packet from the MMT packet and further extracting the reference clock information from the header or payload of the MMT packet, and there are many processes for acquiring the reference clock information, and more time is required until the acquisition. Cost.
  • the processing in the IP layer and higher layers is generally software processing.
  • the reference clock information is stored in the MMT packet, the reference clock information is extracted and reproduced by the software program. In this case, there is a problem that jitter is generated in the acquired reference clock information due to the processing capability of the CPU, interrupts and priorities from other software programs, and the like.
  • a transmission method is a transmission method in content transmission using an IP (Internet Protocol) packet performed through broadcasting, and the first transmission unit in which the IP packet is stored is 1
  • Reference clock information indicating the time for reproducing the content is included in the first transmission unit positioned at the head in the second transmission unit.
  • the receiving apparatus can specify the position of the reference clock information in advance. Therefore, the receiving apparatus can reduce (simplify) the process of acquiring the reference clock information.
  • An example of the first transmission unit is a TLV packet
  • an example of the second transmission unit is a slot
  • an example of a transmission frame is a transmission slot.
  • the first transmission unit may be a variable-length transmission unit
  • the second transmission unit may be a fixed-length transmission unit
  • the IP packet stored in the first transmission unit located at the head may be an IP packet not subjected to header compression.
  • the position of the reference clock information can be specified in more detail on the reception side. Therefore, it is possible to simplify the process in which the receiving device acquires the reference clock information.
  • the first transmission unit is a TLV (Type Length Value) packet
  • the second transmission unit is a slot in the advanced BS transmission system
  • the frame is a transmission slot in the advanced BS transmission system. May be.
  • the reference clock information may be NTP (Network Time Protocol).
  • the frame may be transmitted at a predetermined transmission cycle.
  • a reception method is a reception method in content transmission using an IP packet performed through broadcasting, and includes a second transmission unit including one or more first transmission units in which the IP packet is stored.
  • a transmission apparatus is a transmission apparatus used for content transmission using IP packets performed through broadcasting, and stores one or more first transmission units in which the IP packets are stored
  • a generation unit configured to generate a transmission frame storing a plurality of second transmission units; and a transmission unit configured to transmit the generated frame, wherein the generation unit includes a first second transmission unit in the frame.
  • reference clock information indicating the time for reproducing the content is included on the receiving side.
  • a receiving apparatus is a receiving apparatus used for content transmission using an IP packet performed through broadcasting, and includes a first transmission unit in which at least one first transmission unit is stored.
  • Reception for receiving a frame containing a plurality of transmission units 2 and including reference clock information in the first transmission unit located at the head of the second transmission unit at the head of the frame
  • An extraction unit that extracts the reference clock information from the received frame
  • a generation unit that generates a clock for reproducing the content using the extracted reference clock information.
  • a recording medium such as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable CD-ROM.
  • a recording medium such as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable CD-ROM.
  • These comprehensive or specific aspects may be realized by any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.
  • FIG. 1 shows a protocol stack diagram when transmission is performed using the MMT scheme and the advanced BS transmission scheme.
  • MMT MMT
  • MPUs Media Presentation Units
  • MFUs Media Fragment Units
  • an MMT packet header is also attached to control information such as an MMT message to form an MMT packet.
  • the MMT packet header is provided with a field for storing NTP in a 32-bit short format, and this field can be used for QoS control of a communication line.
  • the MMT packetized data is encapsulated in an IP packet having a UDP header or an IP header.
  • IP packets having the same source IP address, destination IP address, source port number, destination port number, and protocol type in the IP header or UDP header is defined as an IP data flow.
  • the plurality of IP packets included have redundant headers. For this reason, in one IP data flow, some IP packets are header-compressed.
  • FIG. 2 is a diagram illustrating a data structure of a TLV packet.
  • the TLV packet stores an IPv4 packet, an IPv6 packet, a compressed IP packet, a NULL packet, and a transmission control signal. These pieces of information are identified using an 8-bit data type. Transmission control signals include, for example, AMT (Address Map Table) and NIT (Network Information Table). In the TLV packet, a 16-bit field is used to indicate the data length (in bytes), and then the data value is stored. Since there is 1-byte header information before the data type (not shown in FIG. 2), the TLV packet has a total header area of 4 bytes.
  • AMT Address Map Table
  • NIT Network Information Table
  • a TLV packet is mapped to a transmission slot in the advanced BS transmission system, and pointers indicating the beginning position of the first packet and the end position of the last packet included in each slot in TMCC (Transmission and Multiplexing Configuration Control) control information / Slot information is stored.
  • TMCC Transmission and Multiplexing Configuration Control
  • FIG. 3 is a block diagram showing a basic configuration of the receiving apparatus. Note that the configuration of the receiving apparatus in FIG. 3 is simplified, and a more specific configuration will be described later separately according to the manner in which the reference clock information is stored.
  • the receiving device 20 includes a receiving unit 10, a decoding unit 11, a TLV demultiplexer (DEMUX) 12, an IP demultiplexer (DEMUX) 13, and an MMT demultiplexer (DEMUX) 14.
  • a receiving unit 10 includes a receiving unit 10, a decoding unit 11, a TLV demultiplexer (DEMUX) 12, an IP demultiplexer (DEMUX) 13, and an MMT demultiplexer (DEMUX) 14.
  • the receiving unit 10 receives transmission path encoded data.
  • the decoding unit 11 decodes the transmission path encoded data received by the receiving unit 10, performs error correction, and extracts a TMCC control signal and TLV data.
  • the TLV data extracted by the decoding unit 11 is subjected to DEMUX processing by the TLV demultiplexer 12.
  • the DEMUX process of the TLV demultiplexer 12 differs depending on the data type. For example, when the data type is a compressed IP packet, the TLV demultiplexer 12 performs processing such as restoring the compressed header and passing it to the IP layer.
  • the IP demultiplexer 13 performs processing such as header analysis of IP packets or UDP packets, and extracts MMT packets for each IP data flow.
  • the MMT demultiplexer 14 performs a filtering process (MMT packet filtering) based on the packet ID stored in the MMT packet header.
  • MMT packet filtering a filtering process
  • a descriptor, a table, or a message for storing reference clock information is defined and stored in an MMT packet as control information
  • a descriptor, a table indicating reference clock information, or an identifier indicating a message is control information. Shown in The control information is stored in the MMT packet on the transmission side.
  • the receiving device 20 can identify the reference clock information based on the identifier.
  • the reference clock information may be stored in the MMT packet by using an existing descriptor (for example, CRI_descriptor ()).
  • extension field For example, there is a method of storing using a header_extension field (hereinafter referred to as an extension field).
  • the extension field is enabled by setting the extension_flag of the MMT packet header to “1”.
  • an extension field type indicating the data type of data stored in the extension field is stored, and in the extension field type, information indicating reference clock information (for example, 64-bit long format NTP) is stored. There is a method of storing the reference clock information in the extension field.
  • the receiving device 20 refers to the extension field of the MMT packet. If the extended field type indicates that it is reference clock information, the reference clock information is extracted and the clock is reproduced.
  • reference clock information may be stored in an existing header field. Further, when there are unused fields or when there are fields that are not necessary for broadcasting, the reference clock information may be stored in these fields.
  • the reference clock information may be stored using both the existing field and the extension field.
  • an existing 32-bit short format NTP field and an extension field may be used in combination.
  • the reference clock information is, for example, the time when the first bit of the MMT packet in which the reference clock information is stored passes through a predetermined position (for example, when output from a specific component of the transmission apparatus). However, the time when a bit at another position passes a predetermined position may be used.
  • the MMT packet including the control information is transmitted at a predetermined transmission interval.
  • the reference clock information is stored in the extension field of the MMT packet, it is stored in the extension field of the header of the predetermined MMT packet. Specifically, for example, at least one reference clock information is stored in the header extension field of the MMT packet at intervals of 100 ms.
  • the program information stores the packet ID of the MMT in which the reference clock information is stored.
  • the receiving device 20 analyzes the program information and acquires an MMT packet in which the reference clock information is stored.
  • the packet ID of the MMT packet storing the reference clock information may be defined in advance as a fixed value. Thereby, the receiving device 20 can acquire the reference clock information without analyzing the program information.
  • FIG. 4 is a block diagram illustrating a functional configuration of the reception device 20 when the reference clock information is stored in the extension field of the MMT packet header.
  • FIG. 5 is a diagram showing an acquisition flow of the reference clock information of the receiving device 20 when the reference clock information is stored in the extension field of the MMT packet header.
  • the MMT demultiplexer 14 when the reference clock information is stored in the extension field of the MMT packet header, the MMT demultiplexer 14 is provided with a reference clock information extraction unit 15 (an example of an extraction unit).
  • a reference clock generation unit 16 (an example of a generation unit) is provided at the subsequent stage of the multiplexer 14.
  • the decoding unit 11 of the receiving device 20 decodes the transmission path encoded data received by the receiving unit 10 (S101), and extracts the TLV packet from the transmission slot (S102).
  • the TLV demultiplexer 12 performs DEMUX on the extracted TLV packet and extracts an IP packet (S103). At this time, the header of the compressed IP packet is reproduced.
  • the IP demultiplexer 13 demultiplexes the IP packet, acquires the designated IP data flow, and extracts the MMT packet (S104).
  • the MMT demultiplexer 14 analyzes the header of the MMT packet and determines whether or not the extension field is used and whether or not there is reference clock information in the extension field (S106). If there is no reference clock information in the extension field (No in S106), the process is terminated.
  • the reference clock information extraction unit 15 extracts the reference clock information from the extension field (S107). Then, the reference clock generation unit 16 generates a system clock based on the extracted reference clock information (S108). In other words, the system clock is a clock for reproducing content.
  • FIG. 6 is a block diagram illustrating a functional configuration of the receiving device 20 when the reference clock information is stored in the control information.
  • FIG. 7 is a diagram illustrating an acquisition flow of the reference clock information of the reception device 20 when the reference clock information is stored in the control information.
  • the reference clock information extraction unit 15 is arranged at the subsequent stage of the MMT demultiplexer 14.
  • step S111 to step S114 is the same as the flow of step S101 to step S104 described in FIG.
  • the MMT demultiplexer 14 acquires the packet ID of the packet including the reference clock information from the program information (S115), and acquires the MMT packet of the packet ID (S116). Subsequently, the reference clock information extraction unit 15 extracts the reference clock information from the control signal included in the extracted MMT packet (S117), and the reference clock generation unit 16 obtains the system clock based on the extracted reference clock information. Generate (S118).
  • the receiving apparatus 20 extracts the TLV packet from the transmission slot, and the TLV Extract the IP packet from the packet. Further, the receiving device 20 extracts the MMT packet from the IP packet, and further extracts the reference clock information from the header or payload of the MMT packet. As described above, when the reference clock information is stored in the MMT packet, there are many processes for acquiring the reference clock information, and more time is required for the acquisition.
  • processing for assigning a time stamp to media such as video and audio based on the reference clock and processing for transmitting the media are realized using the MMT method, and transmission of the reference clock information is performed lower than the MMT layer.
  • a method performed using a lower layer, a lower protocol, or a lower multiplexing scheme will be described.
  • FIG. 8 is a block diagram illustrating a configuration of the reception device 20 when the reference clock information is stored in the TLV packet.
  • FIG. 8 is different from FIGS. 4 and 6 in the arrangement of the reference clock information extraction unit 15 and the reference clock generation unit 16.
  • the synchronization unit 17 and the decryption presentation unit 18 are also illustrated.
  • the TLV packet is composed of an 8-bit data type, a 16-bit data length, and 8 * N-bit data.
  • a 1-byte header (not shown in FIG. 2) is present before the data type.
  • the data type is specifically defined as, for example, 0x01: IPv4 packet, 0x03: header compressed IP packet, and the like.
  • the data type is defined using the undefined area of the data type.
  • the data type is described to indicate that the data is the reference clock information.
  • FIG. 9 is a diagram illustrating an example in which the long format NTP is stored in the TLV packet, and the long format NTP is stored in the data field.
  • the reference clock information extraction unit 15 analyzes the data type of the TLV packet, and when the reference clock information is stored, analyzes the data length and extracts the reference clock information from the data field.
  • the reference clock information extraction unit 15 may acquire the reference clock information without analyzing the data length field. For example, when it is indicated that the data type is 64 bit long low mat NTP, the reference clock information extraction unit 15 may extract the 4th byte + 1 bit to the 4th byte + 64th bit. Further, the reference clock information extraction unit 15 may extract only desired bits from the 64-bit data.
  • FIG. 10 is a diagram illustrating an acquisition flow of the reference clock information of the reception device 20 when the reference clock information is stored in the TLV packet.
  • the decoding unit 11 decodes the transmission path encoded data received by the receiving unit 10 (S121), and extracts the TLV packet from the transmission slot (S122).
  • the TLV demultiplexer 12 analyzes the data type of the TLV packet (S123), and determines whether the data type is reference clock information (S124).
  • the reference clock information extraction unit 15 extracts the reference clock information from the data field of the TLV packet (S125).
  • the reference clock generation unit 16 generates a system clock based on the reference clock information (S126).
  • the reference clock information acquisition flow ends.
  • the IP demultiplexer 13 extracts the IP packet according to the data type. Then, the IP DEMUX process and the MMT DEMUX process are performed on the extracted IP packet to extract the MMT packet. Further, the synchronization unit 17 outputs the video data to the decoding presentation unit 18 at a timing when the time stamp of the video data included in the extracted MMT packet matches the reference clock generated in step S126, and the decoding presentation unit 18 Decodes and presents video data.
  • the reference clock information is stored in the type data of the TLV packet, and the reference clock information is stored in the data field of the TLV packet.
  • the reference clock information is stored in the data field of the TLV packet.
  • the reference clock information can be extracted and reproduced in lower layers across the IP layer, the reference clock information can be extracted by hardware implementation. As a result, the influence of jitter and the like can be reduced as compared with the case where the extraction of the reference clock information is performed by software implementation, and a reference clock with higher accuracy can be generated.
  • the data length field may not be transmitted.
  • an identifier indicating that the data length field is data that is not transmitted is stored.
  • the reference clock information is stored in the data field of the TLV packet.
  • the reference clock information may be added immediately before or after the TLV packet.
  • the reference clock information may be added immediately before or after the data stored in the TLV packet. In these cases, a data type that can identify the location where the reference clock information is added is assigned.
  • FIG. 11 is a diagram showing a configuration in which the reference clock information is added immediately before the header of the IP packet.
  • the data type indicates an IP packet with reference clock information.
  • the receiving device 20 sets a predetermined reference clock information length from the beginning of the data field of the TLV packet. By extracting the bits, reference clock information can be acquired.
  • the data length may specify the length of data including the length of the reference clock information, or may specify the length not including the length of the reference clock information.
  • FIG. 12 is a diagram showing a configuration in which the reference clock information is added immediately before the TLV packet.
  • the data type is a conventional data type
  • an identifier indicating that the TLV packet is a TLV packet with reference clock information is stored in, for example, the slot header of the transmission slot or TMCC control information.
  • FIG. 13 is a diagram illustrating a configuration of a transmission slot
  • FIG. 14 is a diagram illustrating a configuration of a slot header of the transmission slot.
  • the transmission slot is composed of a plurality of slots (in the example of FIG. 13, 120 slots of Slot # 1-Slot # 120).
  • the number of bits included in each slot is a fixed number of bits uniquely determined based on the error correction coding rate, has a slot header, and stores one or more TLV packets.
  • the TLV packet has a variable length.
  • the position of the first byte of the first TLV packet in the slot is indicated by the number of bytes from the beginning of the slot excluding the slot header. Is stored. The remaining 160 bits of the slot header are undefined.
  • the slot header When an identifier indicating that the TLV packet is a TLV packet with reference clock information is stored in the slot header, for example, information that can specify the position of the TLV packet with reference clock information in the slot, the type of reference clock information, and data The length and the like are stored by extending (using) the undefined field of the slot header.
  • a data type stored in the slot a data type indicating a TLV packet with reference clock information may be defined.
  • an area for storing the reference clock information may be newly defined in the undefined field of the slot header.
  • the reference clock information may be stored in a predetermined slot, or information indicating that the reference clock information is included in the slot header.
  • the predetermined slot is, for example, the first slot (Slot # 1 in the example of FIG. 13) of the transmission slots, and the reference clock stored in the IP packet in the first TLV packet in this slot. Information may be included.
  • FIG. 15 is a block diagram illustrating a functional configuration of the reception device 20 when information indicating that the reference clock information is included in the slot header is stored in the TMCC control information.
  • FIG. 16 is a diagram showing an acquisition flow of the reference clock information when information indicating that the reference clock information is included in the slot header is stored in the TMCC control information.
  • the reference clock information extraction unit 15 is connected to the decoding unit 11. A reference clock signal is obtained from the output transmission slot.
  • the decoding unit 11 decodes the transmission path encoded data (S131), analyzes the TMCC control signal (S132), and determines whether there is reference clock information in the slot header in the transmission slot. (S133). If there is reference clock information in the slot header (Yes in S133), the reference clock information extraction unit 15 extracts the reference clock information from the slot header (S134), and the reference clock generation unit 16 uses the reference clock information based on the reference clock information. A system reference clock (system clock) is generated (S135). On the other hand, if there is no reference clock information in the slot header (No in S133), the reference clock information acquisition flow ends.
  • system clock system clock
  • Such a receiving apparatus 20 can acquire the reference clock information at the layer of the transmission slot, it can acquire the reference clock information even earlier than the case where it is stored in the TLV packet.
  • the reference clock information in the TLV packet or the transmission slot, it is possible to reduce the processing until the reference clock information is acquired in the receiving device 20, and the acquisition time of the reference clock information. Can be shortened.
  • the reference clock information is stored in the physical layer in this way, acquisition and reproduction of the reference clock information by hardware can be easily realized, and a clock with higher accuracy than acquisition and reproduction of the reference clock information by software. Playback is possible.
  • the transmission method according to the first embodiment can be summarized as follows.
  • a system including a plurality of layers (protocols) including the IP layer the time stamp of the media is obtained based on the reference clock information in a layer higher than the IP layer.
  • reference clock information is transmitted in a layer lower than the IP layer. According to such a configuration, it becomes easy for the receiving device 20 to process the reference clock information by hardware.
  • the time at which the first bit of the TLV packet is transmitted on the transmission side is stored as the reference clock information. Further, a predetermined time other than the transmission time of the first bit may be stored as the reference clock information.
  • TLV packets including reference clock information are transmitted at predetermined intervals.
  • the TLV packet including the reference clock information is included in the transmission slot and transmitted at a predetermined transmission cycle.
  • at least one reference clock information may be stored and transmitted in a TLV packet at 100 ms intervals.
  • TLV packets including reference clock information may be arranged at predetermined intervals at predetermined locations in the transmission slot of the advanced BS transmission system.
  • a TLV packet including reference clock information is stored once every 5 slot units, which is a slot allocation unit of the TLV packet, and the reference clock information is stored in the first TLV packet of the first slot among the 5 slot units. May be. That is, the TLV packet including the reference clock information may be arranged at the head of the head slot in the transmission slot (that is, immediately after the slot header).
  • the transmission cycle and the transmission interval of the reference clock information may be changed according to the modulation scheme or coding rate of the transmission path coding scheme.
  • a method for storing reference clock information in an upper layer such as an MMT packet and storing the MMT packet in which the reference clock information is stored in an IP packet will be described.
  • an MMT packet that is an upper layer is directly referenced from a lower layer such as a TLV packet.
  • the reference clock information included in the MMT packet is acquired without performing normal DEMUX processing.
  • the reference clock information is included in the control information stored in the MMT packet described above.
  • a predetermined packet ID is assigned to the control information including the reference clock information.
  • the MMT packet including the reference clock information is stored in a dedicated IP data flow, and the transmission source IP address, destination IP address, transmission source port number, destination port number, and protocol are determined in advance. A type is given.
  • the TLV demultiplexer 12 can extract an IP packet including reference clock information by acquiring a predetermined IP data flow. .
  • the receiving device 20 can extract the IP packet including the reference clock information by referring to the context identifier of the compressed IP packet header.
  • an IP packet including reference clock information may be specified not to be header-compressed, or may be specified to be necessarily header-compressed.
  • a predetermined context identifier may be assigned to the IP packet including the reference clock information, and it may be defined that all headers are compressed.
  • an identifier indicating that the packet is an IP packet belonging to an IP data flow including reference clock information in the data type field of TLV, or an identifier indicating a compressed IP packet belonging to an IP data flow including reference clock information, etc. It is also possible to define The method will be described below.
  • the receiving device 20 determines the TLV data type, and if it is determined that the reference clock information is included, the receiving device 20 directly acquires the reference clock information included in the MMT packet from the IP packet.
  • the receiving device 20 extracts the reference clock information included in the MMT packet by extracting the bit string at the specific position from the IP packet or the compressed IP packet without analyzing the IP address, the port number, or the context identifier. May be.
  • Extracting a bit string at a specific position means, for example, extracting information for a specific length from a position offset by a fixed-length byte from a TLV packet header, and thereby acquiring reference clock information.
  • the fixed length byte offset length for extracting the reference clock information is uniquely determined for each of the IP packet and the compressed IP packet. Therefore, after determining the TLV data type, the receiving apparatus 20 can acquire the reference clock information by immediately extracting information for a specific length from the position offset by a fixed-length byte.
  • the upper layer reference clock information may be acquired from the lower layer by defining other protocols and identifiers.
  • an identifier indicating whether or not the reference clock information is included in the IP packet may be stored in a field other than the TLV data type.
  • the reference time information included in the MMT packet may be extracted by extracting a bit string at a specific position from the IP packet or the compressed IP packet without analyzing the IP address, the port number, and the context identifier.
  • FIG. 17 is a diagram showing a flow when a bit string at a specific position is extracted from an IP packet or a compressed IP packet. Note that the configuration of the receiving device 20 in this case is the same as the block diagram shown in FIG.
  • the decoding unit 11 decodes the transmission path encoded data received by the receiving unit 10 (S141), and extracts a TLV packet from the transmission path slot (S142).
  • the TLV demultiplexer 12 analyzes the data type of the TLV packet and determines whether or not the data type is an IP including the reference clock information (S144). If it is determined that the data type is not an IP packet including reference clock information (No in S144), the flow ends. When it is determined that the data type is an IP packet including the reference clock information (Yes in S144), the IP packet and the MMT packet are analyzed to determine whether the IP header is compressed (S145).
  • reference clock information included in the MMT packet at a position offset by a fixed length N bytes from the TLV header is acquired (S146). If the IP header is compressed (Yes in S145), reference clock information included in the MMT packet at a position offset by a fixed length M bytes from the TLV header is acquired (S147).
  • the reference clock generation unit 16 generates a system clock based on the reference clock information (S148).
  • the data structure of the IP packet header differs depending on whether the IP packet is IPv4 or IPv6, the fixed length N bytes and M bytes have different values.
  • Normal MMT packets including audio, video, and control signals are subjected to DEMUX processing in normal steps, whereas MMT packets including reference clock information are collectively processed by DEMUX processing from a lower layer to an upper layer. Done. Thereby, even if the reference clock information is stored in the upper layer, the reference clock information can be acquired in the lower layer. That is, the processing for acquiring the reference clock information can be reduced, the time until acquisition of the reference clock information can be shortened, and the hardware can be easily implemented.
  • a plurality of reference clock information may be transmitted in one or more layers.
  • the receiving device 20 may select either one of the reference clock information and use it to generate a reference clock (system clock), or use both to generate the reference clock. It may be generated.
  • the receiving device 20 may select highly accurate reference clock information, or may select reference clock information that can be acquired earlier.
  • the reception device 20 can reproduce the 32-bit short format NTP, the NTP field included in the conventional MMT packet header is unnecessary. For this reason, other information may be stored in the NTP field, or header compression may be performed by reducing the NTP field.
  • header compression information indicating that the NTP field has been reduced is transmitted.
  • the receiving apparatus 20 When the NTP field is reduced, the receiving apparatus 20 generates a reference clock using other reference clock information and reproduces a 32-bit short format NTP.
  • the communication receiving apparatus may use the 32-bit short format NTP for QoS control and may not use the reference clock information. Therefore, the reference clock information may not be transmitted on the communication transmission path. If the end-to-end delay of the communication transmission path is within a certain range, the reference clock information may be used for clock recovery.
  • the case where the MMT / IP / TLV method is used has been described as an example.
  • a method other than the MMT method may be used as the multiplexing method.
  • the present disclosure can be applied to the MPEG2-TS system, the RTP system, or the MPEG-DASH system.
  • RoHC Robot Header Compression
  • HCfB Header Compression for Broadcasting
  • GSE Generic Stream Encapsulation
  • ULE Uniform Light-weight. Encapsulation
  • the present disclosure can be applied to any of the above-described methods.
  • the time until acquisition of the reference clock information in the receiving device 20 is reduced, the processing is reduced, and the hardware is implemented. High accuracy of the clock can be realized.
  • FIG. 18 is a block diagram illustrating a functional configuration of the transmission apparatus.
  • FIG. 19 is a diagram illustrating an operation flow of the transmission apparatus.
  • the transmission device 30 includes a generation unit 31 and a transmission unit 32.
  • the components of the transmission device 30 are specifically realized by a microcomputer, a processor, a dedicated circuit, or the like.
  • the transmission device 30 is specifically a broadcast server, and is an example of the “transmission side” in the first embodiment.
  • the generation unit 31 generates, for example, a transmission slot that stores a plurality of slots in which one or more TLV packets in which IP packets are stored are stored (S151 in FIG. 19). Further, the generation unit 31 includes reference clock information such as NTP used for reproduction of content (for example, broadcast content such as video or audio) in the reception device 20 in the TLV packet positioned at the head in the transmission slot. . Specifically, the generation unit 31 includes an encoding unit that encodes broadcast content, an MMT multiplexer, an IP multiplexer, a TLV multiplexer, and the like.
  • the TLV packet is an example of a first transmission unit
  • the slot is an example of a second transmission unit
  • the transmission slot is an example of a transmission frame.
  • the transmission unit 32 transmits the transmission slot (transmission path encoded data including the transmission slot) generated by the generation unit 31 through broadcasting (S152 in FIG. 19).
  • the reception device 20 acquires the reference clock information by including the reference clock information in the TLV packet located at the head in the transmission slot. Processing can be simplified. Therefore, it is possible to shorten the time until the receiving device 20 acquires the reference clock information.
  • each component may be configured by dedicated hardware or may be realized by executing a software program suitable for each component.
  • Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.
  • Each component may be a circuit. These circuits may constitute one circuit as a whole, or may be separate circuits. Each of these circuits may be a general-purpose circuit or a dedicated circuit.
  • another processing unit may execute a process executed by a specific processing unit.
  • the order of the plurality of processes may be changed, and the plurality of processes may be executed in parallel.
  • reception device reception method
  • transmission device transmission method
  • the transmission method of the present disclosure is useful as a transmission method that can reduce processing for acquiring reference clock information on the receiving side when the MMT method is applied to a broadcasting system.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
  • Time-Division Multiplex Systems (AREA)

Abstract

　L'invention concerne un procédé d'émission dans une communication de contenu utilisant un paquet de protocole Internet (IP) réalisée par diffusion générale, le procédé d'émission comprenant une étape de génération (S151) consistant à générer une trame de communications servant à stocker une pluralité de deuxièmes unités de communications dont chacune conserve une ou plusieurs premières unités de communications dans lesquelles est stocké le paquet IP, et une étape d'émission (S152) consistant à émettre la trame générée, l'étape de génération (S151) comprenant, dans la première unité de communications située au début à l'intérieur de la trame, des informations d'horloge de référence indiquant une heure de la journée nécessaire à la reproduction de contenu côté réception. Il en résulte un procédé d'émission capable d'alléger un processus d'acquisition des informations d'horloge de référence côté réception.
PCT/JP2014/004591 2013-09-20 2014-09-08 Procédé d'émission, procédé de réception, appareil émetteur et appareil récepteur WO2015040817A1 (fr)

Priority Applications (6)

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EP20175768.9A EP3758388A1 (fr) 2013-09-20 2014-09-08 Procédé de transmission, procédé de réception, appareil émetteur et appareil récepteur
EP14845940.7A EP3048793B1 (fr) 2013-09-20 2014-09-08 Procédé d'émission, procédé de réception, appareil émetteur et appareil récepteur
CN201480040274.1A CN105379290B (zh) 2013-09-20 2014-09-08 发送方法、接收方法、发送装置及接收装置
US15/063,602 US10070199B2 (en) 2013-09-20 2016-03-08 Transmission method, reception method, transmission apparatus, and reception apparatus
US16/047,642 US11082750B2 (en) 2013-09-20 2018-07-27 Transmission method, reception method, transmission apparatus, and reception apparatus
US17/361,488 US20210345008A1 (en) 2013-09-20 2021-06-29 Transmission method, reception method, transmission apparatus, and reception apparatus

Applications Claiming Priority (4)

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US201361880304P 2013-09-20 2013-09-20
US61/880,304 2013-09-20
JP2014173071A JP6382029B2 (ja) 2013-09-20 2014-08-27 送信方法、受信方法、送信装置、及び受信装置
JP2014-173071 2014-08-27

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