JP6389585B1 - Transmitting apparatus and receiving apparatus - Google Patents

Abstract

Provided are a transmission device and a reception device capable of efficiently transmitting a variable-length packet such as an IP packet simultaneously with transmission of a digital broadcast TS.
When a variable-length packet is multiplexed and transmitted in a plurality of TS multiplexed frames, the transmission device of the present invention divides the variable-length packet and assigns it to a third packet having the same packet length as the TS packet. An array for forming the packet sequence of the third packet with the start position information added to the data of the start position of the long packet, and indicating the relative arrangement position in the frame regarding the TS packet and the third packet The multi-frame header information is generated so as to include the position information. The receiving device 20 of the present invention receives this multiplexed signal, refers to the array position information, separates the third packet from the plurality of TS multiplexed frames, extracts the third packet, and restores the variable-length packet. To do.
[Selection] Figure 1

Description

  The present invention relates to a transmission apparatus that multiplex-transmits variable-length packets together with a transport stream (TS) and a reception apparatus thereof.

  In digital broadcasting, video signals and audio signals are multiplexed and transmitted using a transport stream. A typical example of a transport stream is a group of fixed-length (188 byte) packet column information starting with a synchronization byte 0x47 such as a packet of an MPEG-2 transport stream (hereinafter referred to as a “TS packet”). It is.

  In the current cable television, one TS packet format header slot per frame and 52 TS placement packet placements conforming to the Japan CATV Technology Association standard (for example, see Non-Patent Document 1) A plurality of TS multiplexed frames (TSMF) consisting of slots are used. Using this frame, a retransmission service by transmodulation of BS digital broadcasting and terrestrial digital broadcasting is operated.

  On the other hand, in order to add a file-type content distribution service for communication and storage, IP (Internet Protocol) packets are multiplexed in addition to TS from one modulator, such as satellite broadcasting, terrestrial broadcasting, and cable television independent broadcasting. Several methods for enabling transmission have been proposed.

  The “techniques that enable transmission of IP packets in addition to TS” that have been proposed so far can be broadly divided into two.

  The first technique for enabling transmission of IP packets is a method of dividing (accommodating) IP packets into MPEG-2 Systems TS packets, and is an MPE (Multi-Protocol Encapsulation) (for example, non-patent document). 2) and ULE (Unidirectional Lightweight Encapsulation) (for example, see Non-Patent Document 3). MPE is a system in which IP packets are encapsulated in a section format defined by MPEG-2 Systems and stored in TS packets. In ULE, an EtherType field, a destination address field, and a CRC field are added to an IP packet, and then encapsulated into a private stream defined by MPEG-2 Systems and stored in a TS packet. Since these schemes are TS packets as seen from the transmission path coding side, a transmission scheme for transmitting an existing TS can be used, a scheme for performing a new service using IP and a scheme for transmitting only a conventional TS. It is thought that it is easy to make a receiver to receive in common. In Japan, using a terrestrial digital broadcast transmission method, a method using ULE is adopted in multimedia broadcasting ISDB-Tmm.

  The second technique for enabling transmission of IP packets is realized by advanced BS digital broadcasting (for example, see Non-Patent Document 4), DVB-C2 (for example, Non-Patent Document 5), and the like. In advanced BS digital broadcasting, an IP packet is encapsulated in a TLV (type length value) packet (for example, see Non-Patent Documents 6 and 7), and a transmission path is established by assigning a TLV packet to a slot different from the slot in which the TS is arranged. Sharing. Since slots in a frame have a fixed length, a technique for describing the start position of a TLV packet for each packet placement slot in TMCC in order to allocate variable-length TLV packets without waste is disclosed (for example, patents). Reference 1). On the other hand, in DVB-C2, GSE (Generic Stream Encapsulated) and TS encapsulating an IP packet are converted into a common signal format called PLP (Physical Layer Pipe), and this is framed and transmitted.

  Incidentally, bi-directional transmission of IP packets used for communication services on cable television is realized by Docsis (Data-over-cable Service Interface Specifications) (for example, see Non-Patent Document 8). In Docsis, a packet having a total length of 188 bytes composed of a 4-byte unique MAC header and a payload carrying an IP packet is transmitted.

  In addition, the existing transmission system for transmitting TS is expanded to form a multiple TS multiplexed frame (TSMF) as used in cable television, and at the same time as transmitting digital broadcasting TS, IP packets, etc. A technique for multiplexing and transmitting a variable-length packet in TSMF is disclosed (for example, see Patent Document 2).

JP 2008-136052 A JP 2013-175949 A

JCTEA STD-002 5.0 version, "Digital broadcasting cable television broadcasting multiplexing device", Japan CATV Technology Association, October 2007 ETSI EN 301 192-V1.4.1, “Digital Video Broadcasting (DVB); DVB Specification for data broadcasting,” European Standard, June 2004 G. Fairhurst and B. C. Nocker, “Unidirectional Lightweight Encapsulation (ULE) for Transmission of IP Datagrams over an MPEG-2 Transport Stream (TS)”, IETF, RFC 4326, December 2005 ARIB STD-B44 version 1.0, "Transmission system for advanced broadband satellite digital broadcasting", The Japan Radio Industry Association, July 29, 2009 ETSI EN 302 769-V1.2.1, “Digital Video Broadcasting (DVB); Frame structure channel coding and modulation for a second generation digital transmission system for cable systems (DVB-C2)”, April 2011 S. Aoki and K. Aoki, “Efficient Multiplexing Scheme for IP Packets over the Advanced Satellite Broadcasting System”, IEEE Transactions on Consumer Electronics, vol. 55, no. 1, pp.49-55, February 2009 ARIB STD-B32 1.0, “Video Coding, Audio Coding and Multiplexing in Digital Broadcasting”, The Japan Radio Industry Association, May 31, 2001 CableLabs, Data-Over-Cable Service Interface Specifications (DOCSIS) 3.0, CM-SP-MULPIv3.0-I17-111117, “MAC and Upper Layer Protocols Interface Specification”, November 17, 2011

  MPE and ULE systems that encapsulate IP packets in MPEG-2 Systems TS packets have the advantage of using existing transmission systems for transmitting TS as described above, but in addition to IP header information. It is necessary to add a TS packet header, a private stream header, and a section header as packet header information. Further, when IP packets are accommodated in fixed-length TS packets, there is a possibility that stuffing may occur, resulting in a disadvantage that overhead is increased and transmission efficiency is poor. In DVB-C2, according to Non-Patent Document 5, if the payload length is about 2000 bytes, 5% to 14%, if it is about 4000 bytes, 4% to 8% is the overhead ratio. . In Docsis, according to Non-Patent Document 8, if the payload length is about 2000 bytes, it is about 15% for 64QAM, about 13% for 256QAM, and about 14% for 64QAM when the payload length is about 4000 bytes. %, 256QAM is approximately 12% overhead. However, advanced BS digital broadcasting and DVB-C2 employ a method of reducing the overhead ratio as described above, and transmission efficiency has an advantage over Docsis.

  On the other hand, when configuring a shared receiver for the existing transmission scheme for transmitting TS and advanced BS digital broadcasting, DVB-C2 or Docsis, it must support a plurality of transmission schemes. There is a problem that leads to an increase in cost.

  In order to solve this problem, in the technique according to Patent Document 2, an existing transmission method for transmitting TS is expanded, and a plurality of TS multiplexed frames (TSMF) as used in cable television are configured. At the same time as transmitting a digital broadcasting TS, a variable length packet such as an IP packet is multiplexed and transmitted in TSMF. In this technique, all information necessary for multiplexing or demultiplexing the variable-length packet into TSMF (including information for dividing or restoring the variable-length packet), in particular, the data of the divided variable-length packet is changed to the original variable. In order to store all the information necessary to restore a long packet in the extension information area (680 bits) provided in the frame header of TSMF, the receiver is in an extended form of the existing transmission method. Even when a shared receiver as described above is configured, it is possible to suppress the increase in cost and efficiently transmit variable-length packets such as IP packets at the same time as transmitting digital broadcasting TS. it can.

  However, in the technique according to Patent Document 2, since the processing load of the frame header of TSMF increases by the amount of information stored in the extension information area, the information amount to be stored in the extension information area is reduced as described above. A technique for suppressing an increase in cost when a shared receiver as described above is configured is desired. Further, according to the technique disclosed in Patent Document 2, when the extension information area of the TSMF is used, the extension information area that can be used to realize a new service in the future is reduced.

  An object of the present invention has been made in consideration of the above-described problems, and is capable of efficiently transmitting variable-length packets such as IP packets at the same time as transmitting digital broadcasting TS. Is to provide.

  In general, the transmission apparatus according to the present invention is a third packet having the same packet length as a TS packet for dividing and storing variable-length packet data (referred to as “TS-like packet” in this specification). 2) information for dividing or restoring the variable length packet (information for indicating the start position of the variable length packet) and the third packet. And a flag for distinguishing whether or not the head position of the variable-length packet is included. Among these, a flag for distinguishing whether or not the head position of the variable-length packet to be divided is included is described in the header of the third packet. The flag may be described in the multiplexed frame header information of a plurality of TS multiplexed frames (for example, the extension information area of TSMF). In the multi-frame header information, array position information for indicating a relative array position in the frame regarding the TS packet and the third packet is described. However, when the predetermined stream identification information (information for identifying the stream to which the data of each packet belongs) described in TSMF is configured so that the TS packet and the third packet can be discriminated, the arrangement position It is not always necessary to describe the information in the extension information area of TSMF, that is, the amount of use of the extension information area of TSMF can be further reduced. Information for indicating the head position of the variable-length packet is configured to be added as head position information to the third packet including the data of the head position of the variable-length packet. This reduces the amount of information stored in the extension information area of TSMF.

  Also, the receiving apparatus of the present invention multiplexes multiple TS multiplexed frames in which variable length packet data is multiplexed in a frame composed of a plurality of packet placement slots to which TS packets are allocated and one slot for multiple frame header information. When separating the TS packet and the third packet including the variable-length packet data from the signal, the relative arrangement position in the frame included in the multiplexed frame header information of the plurality of TS multiplexed frames is indicated. The third packet is determined and separated from either or both of the array position information and the stream identification information for identifying the stream to which the data of each packet belongs. Subsequently, the receiving apparatus of the present invention refers to a flag for distinguishing whether or not the start position of the variable length packet is included for the data of the variable length packet, and receives the third packet including the start position. The packet of the third packet is obtained by determining and extracting the head position information, which is information for indicating the head position of the variable length packet stored in the third packet, to grasp the head position of the variable length packet. Combine column data and restore variable length packet.

  That is, the transmission apparatus of the present invention is a transmission apparatus that multiplex-transmits a variable-length packet in a frame composed of a plurality of packet placement slots to which TS (Transport Stream) packets are allocated and one multi-frame header information slot, Generate a third packet having the same packet length as the TS packet to be transmitted, divide the variable length packet to be transmitted, and sequentially assign the divided variable length packet data to the third packet, The same synchronization byte as that of the TS packet is added to the received data, and the head position information indicating the head position of the variable length packet is added to the data located at the head position of the variable length packet. Variable length packet dividing means for forming a packet sequence of the third packet, and a plurality of predetermined packet placement slots. Multi-frame header generation means for generating multi-frame header information defining a data structure arrangement of the TS packet and the third packet in the frame to be transmitted, and based on the multi-frame header information, the TS packet and the third packet A variable means comprising: multiplexing means for arranging and multiplexing packets for each packet placement slot to configure a plurality of TS multiplexed frames; and transmitting means for transmitting a multiplexed signal of the plurality of TS multiplexed frames to the outside. A flag for distinguishing whether or not to include the start position of a long packet is included in the third packet, and the start position information of the variable length packet is included in the multiplexed frame header information And the flag is the leading position of the variable-length packet in the third packet. Is placed only when it indicates that it contains, and the placed head position information is a 1-byte description of a numerical value indicating in which position the head position of the variable-length packet is in the third packet. The multi-frame header generation means includes means for generating the multi-frame header information so as to include arrangement position information for indicating a relative arrangement position in the frame relating to the TS packet and the third packet. It is characterized by.

  Furthermore, the receiving apparatus of the present invention multiplexes multiple TS multiplexed frames in which variable length packet data is multiplexed in a frame composed of a plurality of packet placement slots to which TS packets are allocated and one slot for multiple frame header information. A receiving device for receiving variable-length packet data from a signal, receiving means for receiving a multiplexed signal of the multiple TS multiplexed frames, and the multiple TS multiplexing with reference to multiplexed frame header information of the multiple TS multiplexed frames Separating means for extracting and separating the third packet including the data of the variable-length packet from the frame, and extracting the head position information of the variable-length packet stored in the third packet, and the head of the variable-length packet The variable-length packet is extracted from the packet sequence of the third packet based on the position information and synthesized. Variable length packet restoring means for restoring, a flag for distinguishing whether or not the head position of the variable length packet is included is included in the third packet, and the head of the variable length packet The position information is configured without being included in the multi-frame header information, and is disposed only when the flag indicates that the variable packet includes the head position in the third packet. The position information is a numerical value indicating one position in the third packet in 1 byte, and the multi-frame header information is a relative value in the frame related to the TS packet and the third packet. The separation means refers to the arrangement position information and refers to the arrangement position information from the plurality of TS multiplexed frames. The variable length packet restoring means extracts the leading position information of the variable length packet stored in the third packet with reference to the flag, and the leading position information The head position of the variable-length packet is determined based on the numerical value indicated by.

  This makes it possible to encapsulate variable-length packets into packets with a low overhead of TS packet length, and to multiplex variable-length packets simultaneously with TS packets. It is possible to transmit efficiently while sharing. In the transmission apparatus of the present invention, the same synchronization pattern as that of the TS packet (for example, 0x47) is added to the head of the third packet (that is, “TS-like packet” in the present specification) for storing variable-length packet data. Is described in the first byte of the slot), it is possible to reduce the demodulation processing for identifying the TS packet and the third packet on the receiving side, and to transmit efficiently.

  In particular, two pieces of information for dividing or restoring a variable-length packet are distinguished (information for indicating the start position of a variable-length packet and whether the TS-like packet includes the start position of a variable-length packet) For efficient transmission while improving the utilization efficiency of multiframe header information that defines the data structure arrangement of TS packets and TS-like packets in multiple TS multiple frames (TSMF). It becomes possible.

  In particular, since the information about the head position of the variable-length packet is stored in the TS-like packet without being described in the multi-frame header information, the data structure of the TS packet and TS-like packet in the multiple TS multi-frame (TSMF) It is possible to efficiently transmit while improving the utilization efficiency of the multi-frame header information that defines the arrangement.

  Further, the variable length packet according to the present invention can be any of an IP packet, a TLV packet, or a GSE packet. In this way, a signal in which any type of variable-length packet having packet length information is multiplexed can be transmitted.

  Further, the multiplexed signal according to the present invention can be transmitted through a transmission line of a cable television. This makes it possible to transmit IP packet data in a TLV packet format that can also be used for advanced BS digital broadcasting, thereby increasing the sharing rate of the transmission equipment, and wide use and high utilization efficiency in consideration of the retransmission device A transmission system can be constructed.

  Therefore, for example, it is possible to construct a transmission system that can efficiently multiplex variable-length packets simultaneously with TS packets by efficiently using the extension information area of the currently used TSMF frame header. In this transmission system, the amount of information stored in the extension information area of TSMF for transmitting information necessary for multiplexing or demultiplexing variable-length packets into TSMF can be reduced. It is possible to secure an area of extended information that can be used for the realization.

It is a schematic block diagram of the transmitter of 1st Embodiment by this invention. It is a figure explaining the example of a variable length packet division | segmentation in the variable length packet division part in the transmitter of 1st Embodiment by this invention. It is a figure which shows an example of the multiple TS multiplexing frame in the transmission apparatus of 1st Embodiment by this invention. It is a figure which shows an example of the multi-frame header information in the transmitter of 1st Embodiment by this invention. It is a schematic block diagram of the receiver of 1st Embodiment by this invention. It is a schematic block diagram of the transmitter of 2nd Embodiment by this invention. It is a figure explaining the example of a variable length packet division | segmentation in the variable length packet division part in the transmitter of 2nd Embodiment by this invention. It is a figure which shows an example of the multi-frame header information in the transmission apparatus of 2nd Embodiment by this invention. It is a schematic block diagram of the receiver of 2nd Embodiment by this invention.

  Hereinafter, the transmitting device 10 and the receiving device 20 of each embodiment according to the present invention will be described in detail with reference to the drawings. In the example of each embodiment, an example will be described in which a variable-length packet such as an IP packet, a TLV packet, or a GSE packet is multiplexed and transmitted in a plurality of TS multiplexed frames (TSMF) simultaneously with the TS packet. The multiple TS multiplex frame (TSMF) is composed of a plurality of packet arrangement slots for assigning TS packets and one multiplex frame header information slot.

<First Embodiment>
[Transmitter]
FIG. 1 is a schematic configuration diagram of a transmission apparatus 10 according to the first embodiment of the present invention. The transmission apparatus 10 includes a variable length packet division unit 11, a multiplexing unit 12, a multiplexed frame header generation unit 13, and a transmission unit 14. As will be apparent from the description below, the transmission device 10 of the present embodiment includes the function blocks of the transmission device disclosed in Patent Document 2 as the functions of the variable-length packet division unit 11 and the multiplex frame header generation unit 13. Note the differences.

  The variable length packet division unit 11 generates a third packet (hereinafter referred to as “TS-like packet”) having a packet length (fixed length of 188 bytes) having the same size as the TS packet to be transmitted, and transmits the third packet. The packet is divided and the data of the divided variable-length packet is encapsulated by sequentially assigning to the TS-like packet and output to the multiplexing unit 12. Here, when the variable length packet dividing unit 11 divides the variable length packet into TS-like packets and assigns data, the variable length packet dividing unit 11 adds the same synchronization byte (0x47) as the TS packet to each divided data, For data located at the head position of the variable length packet, head position information indicating the head position of the variable length packet is added to form a TS-like packet. Accordingly, the “head position information” is added to the third packet including the data of the head position of the variable length packet. For this reason, the variable length packet dividing unit 11 sends a flag (preferably 1 bit) for distinguishing whether or not the head position of the variable length packet is included in the TS-like packet to the multiplexed frame header generating unit 13. Supply. Therefore, “head position information” of the variable length packet according to the present embodiment is different from the technique of Patent Document 2 and is described in the multiplexed frame header information (TSMF extension information area) of the multiple TS multiplexed frames. You do n’t have to.

  In order to transmit the TS packet and TS-like packet in a frame having a plurality of predetermined packet placement slots, the multiplex frame header generation unit 13 performs relative processing in the frames related to the TS packet and TS-like packet. Multiple frame header information including array position information (that is, information indicating the stream type) for indicating the array position and a flag indicating whether or not the start position of the variable length packet supplied from the variable length packet division unit 11 is included. Is generated and sent to the multiplexing unit 12. Although the multi-frame header information according to the present invention will be described in detail later, the above-described array position information is used as the data structure array for the data structure array information based on the slot array in the existing multiple TS multiple frames (TSMF). The information is extended to be described in the extended information area. However, when the configuration is such that the TS packet and the third packet can be discriminated as the default stream identification information described in the TSMF, it is not always necessary to describe the arrangement position information in the extension information area of the TSMF. That is, it is not necessary to use the extension information area of the TSMF as information for multiplexing or demultiplexing the variable-length packet into the TSMF, in addition to the above flag.

  Multiplexer 12 arranges one multiframe header information slot in one frame, inputs TS packets and TS-like packets output from variable length packet divider 11, and receives multiple frames header generator 13. Based on the data structure indicated by the supplied multiplex frame header information, TS packets and TS-like packets are arranged and multiplexed for each packet allocation slot of the one frame, and a plurality of slots are added by adding the slots of the multiplex frame header information. This is configured as a TS multiplexed frame, and the multiplexed signal of the plurality of TS multiplexed frames is output to the transmitter 14.

  The transmission unit 14 performs predetermined coding modulation on the multiplexed signal of the multiple TS multiplexed frames obtained from the multiplexing unit 12 and transmits the resultant signal as a carrier wave to the outside. For example, a carrier wave (multiplexed signal) based on a plurality of TS multiplexed frames (TSMF) is distributed to a cable television subscriber's home through a cable television transmission path.

  Here, in the technique of Patent Document 2, all the information regarding the head position of the variable-length packet in the TS-like packet is included in the header information of the multiple TS multiplexed frame. In the apparatus 10, a plurality of TS multiplexing flags (preferably 1 bit) for distinguishing whether or not the head position of the variable length packet is included by the functions of the variable length packet dividing unit 11 and the multiplexed frame header generating unit 13. The difference is that the TS-like packet corresponding to the flag indicating that the start position of the variable length packet is included in the multiple frame header information of the frame is configured to accommodate the start position information of the variable length packet. To do.

  More specifically, the technique of Patent Document 2 is based on a data structure indicated by header information of a plurality of TS multiplexed frames including information on the start position of a variable-length packet and arrangement position information (that is, information indicating the stream type). In addition, the transmission apparatus 10 according to the present invention is configured to form a TS-like packet that encapsulates the divided variable-length packet data. However, in the transmission apparatus 10 according to the present invention, the arrangement position information and / or the TS packet and the third packet The frame identification information includes stream identification information configured to be able to discriminate the packet and a flag (preferably 1 bit) for distinguishing whether or not the TS-like packet includes the beginning position of the variable-length packet. The difference is that the data of the divided variable-length packet is encapsulated based on the data structure indicated by this multi-frame header information. That. In addition, when the transmission apparatus 10 according to the present invention divides a variable-length packet into TS-like packets and assigns the data, the transmission apparatus 10 newly adds data according to the present invention to data located at the head position of the variable-length packet. The difference is that a TS-like packet is formed by adding head position information indicating the head position of the defined variable-length packet.

  As described above, according to the transmitting apparatus 10 of the present invention, two pieces of information for dividing or restoring a variable-length packet (information for indicating the head position of the variable-length packet and variable in the TS-like packet). Since it is transmitted separately in a flag for distinguishing whether or not the head position of a long packet is included, the overhead is reduced as the transmission efficiency and the use efficiency of the multi-frame header information is improved and the variable length is efficiently changed. Packets can be multiplexed and transmitted.

  FIG. 2 shows an example of division in the variable length packet division unit 11. In the example shown in FIG. 2, the variable length packet dividing unit 11 divides the input variable length packet # 1 into data of 186 bytes from the beginning. This is encapsulated in a TS-like packet # 1 having a length of 188 bytes, in which a synchronization byte (0x47) of 1 byte is added to the head and head position information (1 byte) is added to the second byte, and is supplied to the multiplexing unit 12.

  Next, the variable length packet dividing unit 11 calculates the remaining length of the variable length packet # 1 from the packet length information stored in the variable length packet # 1. When the length of the remaining variable-length packet is “187 bytes or more”, 187-byte data is divided and encapsulated in a TS-like packet # 2 with a synchronization byte (0x47) added to the head. When the length of the remaining variable-length packet is “less than 186 bytes”, as with the TS-like packet # 1, a 1-byte synchronization byte (0x47) is added to the head, and head position information is added to the second byte. A TS-like packet to which (1 byte) is added is assumed.

  However, when the length of the remaining variable-length packet is “186 bytes”, head position information indicating that the head position of the variable-length packet is present at the third byte of the TS-like packet # 3 is added. This is because the receiver side determines whether the head position information in the TS-like packet # 3 is the second byte or the third byte, so that the TS-like packet # 2 is data of a synchronization byte and a variable length packet. This is to make it possible to identify the length of variable-length packets up to TS-like packet # 2. That is, in this case, on the transmitting side, dummy data is inserted into the last byte data of the TS-like packet # 2 and the second byte data of the TS-like packet # 3, and on the receiving side, the TS-like packet # 3 is inserted. By determining whether the head position information in 3 is the second byte or the third byte, the length of the variable-length packet up to the TS-like packet # 2 can be identified. It should be noted that a null-length variable-length packet is inserted so that the remaining variable-length packet is not “186 bytes” in length, and the leading position of the variable-length packet in the TS-like packet is adjusted. It can also be configured.

  In the example shown in FIG. 2, the value of the head position information of the variable-length packet is “0” indicating the second byte counted from the synchronization byte (0x47) of the first TS-like packet # 1, and the third It becomes 'X-2' indicating the X byte of the TS-like packet # 3, and 'Y-2' indicating the Y byte of the fourth TS-like packet # 4. Here, X-2 is the length of the data that is divided into variable-length packet # 1 and placed in TS-like packet # 3, and Y-2 is the variable length packet # 2 that is divided into TS-like packet # 3. 4 is the length of data to be arranged.

  Note that the technique of Patent Document 2 is configured such that 8 bits indicating information on the head position of a variable-length packet are assigned to each packet placement slot in the frame in the header information of a plurality of TS multiplexed frames. In this case, it is necessary to secure an extended information area describing 416 bits (52 slots × 8 bits) in the header information. On the other hand, in the technique according to the present invention, a flag indicating whether or not the TS-like packet includes the head position is indicated by 1 bit, so that only 52 bits (52 slots × 1 bit) are included in the multiplexed frame header information (TSMF). It is sufficient to secure it in the extended information area in the header information, and the information amount of the header information can be reduced by 364 bits.

  Next, a specific configuration example of multiple TS multiple frames (TSMF) and multiple frame header information will be described. FIG. 3 is a diagram illustrating an example of a plurality of TS multiple frames (TSMF) in the transmission apparatus 10. The multiple TS multiplex frame (TSMF) has a slot for storing multiplex frame header information according to the present invention and 52 packet placement slots for assigning TS-like packets and TS packets, and the slot length is 188 bytes. .

  FIG. 4 shows an example of multiframe header information according to the present invention. First, in the data structure arrangement information in the frame of TS packets at the time of multiple TS transmission that is currently operated in compliance with the Japanese CATV Technology Association standard, the correspondence between the TS identifier (ts_id) and the original network identifier (original_network_id) Is given as a relative TS number (relative_ts_number; maximum value 15). The relative TS number indicates the relative TS number of the TS packet stored in each packet placement slot of the frame. The data structure arrangement information is given by using the relative TS number to indirectly correspond to the order of the table of ts_id / original_network_id.

  Therefore, in the transmission apparatus 10 of the present embodiment, the data structure arrangement information of the existing multiple TS multiplexed frames is expanded, and a new TS-like packet and TS packet are arranged for each packet arrangement slot in the frame. In order to obtain data structure array information, array position information (stream type information) indicating whether a stream is a TS packet for each ts_id / original_network_id or whether a stream is a TS-like packet for each TLV_id / original_network_id ) Is newly added to the extension information area in the header information of the TSMF. In this way, the multiplex frame header generation unit 13 indicates the arrangement of each TS-like packet and TS packet for each packet arrangement slot in the frame by the arrangement position information (stream type information), and the variable length packet. New data structure array information indicating whether the packet is a variable-length packet including head position information by a flag (preferably 1 bit) for distinguishing whether the head position is included or not is used as multiframe header information Generate.

  However, if the stream identification information (ts_id / original_network_id and TLV_id / original_network_id) is configured so that it can be determined whether the identifier is a TS identifier (ts_id) or a variable-length packet identifier (eg, TLV_id), the array Position information (stream type information) can be omitted from the multiplexed frame header information (TSMF header).

[Receiver]
FIG. 5 is a schematic configuration diagram of the receiving device 20 according to the first embodiment of the present invention. The receiving device 20 is a device that receives variable-length packet data from a multiplexed signal of TS packet sequences having header information in the TS packet format. The receiving device 21, the separating unit 22, the variable-length packet restoring unit 23, Is provided. As will be apparent from the following description, the receiving device 20 of the present embodiment is different from the functional block of the receiving device disclosed in Patent Document 2 as functions of the separation unit 22 and the variable length packet restoration unit 23. Keep in mind.

  The receiving unit 21 receives and demodulates a carrier wave (multiplexed signal) of a packet sequence transmitted in a plurality of TS multiplexed frames having TS packet format header information as multiplexed frame header information according to the present invention illustrated in FIG. , And sent to the separation unit 22. In particular, since the same synchronization pattern is given to the TS packet and the TS-like packet, the receiving unit 21 can receive these packets as the same packets of the multiple TS multiplexed frames.

  The separation unit 22 extracts and separates TS packets and TS-like packets from a plurality of TS multiplexed frames based on the multiplexed frame header information. More specifically, the separation unit 22 includes arrangement position information for indicating a relative arrangement position in a frame related to a TS packet and a TS-like packet having the same packet length as the TS packet from the multiplexed frame header information. A flag for distinguishing whether or not the head position of the variable length packet is included is extracted, the TS-like packet is separated from the TSMF packet sequence based on the arrangement position information, and the TS-like packet is changed to the variable length. The packet is sent to the variable length packet restoration unit 23 together with a flag for distinguishing whether or not the head position of the packet is included. However, if the TS packet and the TS-like packet are configured to be discriminated by the stream identification information (ts_id / original_network_id and TLV_id / original_network_id) that is information for identifying the stream to which the data of each packet belongs, Since it is not necessary to describe the array position information in the multiplexed frame header information, the separating unit 22 separates the TS position and the TS-like packet from the multiplexed signal of the multiple TS multiplexed frames. The TS-like packet can be discriminated and separated from one or both of the stream identification information and the stream identification information.

  The variable-length packet restoration unit 23 refers to a flag for distinguishing whether or not the leading position of the variable-length packet stored in the multiframe header information is included, and the variable-length packet stored in the TS-like packet The head position information of the packet is extracted, data is extracted from the packet sequence of the TS-like packet based on the head position information of the variable length packet, and the variable length packet is restored.

  As described above, in the receiving device 20, the receiving unit 21 demodulates the received carrier wave, extracts a plurality of TS multiplexed frames, and outputs them to the demultiplexing unit 22. In the demultiplexing unit 22, the array stored in the multiframe header information A TS packet and a TS-like packet are separated based on position information and / or stream identification information. The separated TS-like packet is supplied to the variable-length packet restoring unit 23 together with the flag related to the head position of the variable-length packet. The variable length packet restoration unit 23 combines the data of the TS-like packet packet sequence based on the leading position information of the variable length packet extracted with reference to the flag related to the leading position of the variable length packet, and restores the variable length packet. To do.

  Here, in the technique of Patent Document 2, the data of the TS-like packet is separated from the TSMF packet sequence based on the arrangement position information stored in the multiframe header information and the information on the start position of the variable length packet. However, in the receiving apparatus 20 according to the present invention, the arrangement position information and / or the stream identification information is obtained by the functions of the separation unit 22 and the variable length packet restoration unit 23. Based on the TSMF packet sequence, the TS-like packet is separated, and the head position information in the TS-like packet is extracted based on a flag for distinguishing whether or not the head position of the variable-length packet is included. As a result, the data of the packet sequence of the TS-like packet is synthesized based on the head position information, and the variable length packet is restored. It is different in that it is configured.

  As described above, according to the receiving device 20 according to the present invention, the head position of the variable-length packet in the TS-like packet can be immediately grasped while the amount of information of the multiframe header information is reduced. It is possible to efficiently restore the variable length packet based on the head position information of the variable length packet in the TS-like packet.

  Therefore, according to the transmission system of the transmission device 10 and the reception device 20 according to the present invention, the variable length packet is encapsulated into a packet of a format with a small overhead of the TS packet length, and the variable length packet is multiplexed simultaneously with the TS packet. Therefore, transmission can be efficiently performed while sharing the transmission equipment even in the configuration of the transmission path. In particular, two pieces of information for dividing or restoring a variable-length packet are distinguished (information for indicating the start position of a variable-length packet and whether the TS-like packet includes the start position of a variable-length packet) Therefore, it is possible to efficiently multiplex and transmit variable-length packets while reducing the overhead as the transmission efficiency and improving the utilization efficiency of the multiplexed frame header information.

  For example, it is possible to construct a transmission system that can multiplex variable-length packets with TSMF simultaneously with TS packets by using a transmission path of a currently used TSMF transmission method. Furthermore, in this transmission system, the amount of information stored in the extension information area of the TSMF required for information required for multiplexing or demultiplexing variable-length packets into the TSMF can be reduced as compared with the technique of Patent Document 2. Therefore, it is possible to secure an area for extended information that can be used to realize a new service in the future.

  Next, the transmitting device 10 and the receiving device 20 according to the second embodiment of the present invention will be described in detail with reference to the drawings. In the second embodiment, the same reference numerals are assigned to the same components as those in the first embodiment. In this example, an example will be described in which a variable-length packet such as an IP packet, a TLV packet, or a GSE packet is multiplexed and transmitted in a plurality of TS multiplexed frames (TSMF) simultaneously with the TS packet. The multiple TS multiplex frame (TSMF) is composed of a plurality of packet arrangement slots for assigning TS packets and one multiplex frame header information slot.

Second Embodiment
[Transmitter]
FIG. 6 is a schematic configuration diagram of the transmission device 10 according to the second embodiment of the present invention. The transmission apparatus 10 includes a variable length packet division unit 11, a multiplexing unit 12, a multiplexed frame header generation unit 13, and a transmission unit 14. As will be apparent from the description below, the transmission device 10 of the present embodiment includes the function blocks of the transmission device disclosed in Patent Document 2 as the functions of the variable-length packet division unit 11 and the multiplex frame header generation unit 13. Note the differences.

  The variable length packet division unit 11 generates a third packet (hereinafter referred to as “TS-like packet”) having a packet length (fixed length of 188 bytes) having the same size as the TS packet to be transmitted, and transmits the third packet. The packet is divided and the data of the divided variable-length packet is encapsulated by sequentially assigning to the TS-like packet and output to the multiplexing unit 12. Here, when the variable length packet dividing unit 11 divides the variable length packet into TS-like packets and assigns data, the variable length packet dividing unit 11 adds the same synchronization byte (0x47) as the TS packet to each divided data, In addition to distinguishing whether or not each third packet includes the leading position of the variable-length packet, this “numerical value indicating the leading position when the leading position is included” and “when the leading position is not included, this is indicated. “Start position information” describing “numerical value” is accommodated in the third packet. Therefore, “head position information” of the variable length packet according to the present embodiment is different from the technique of Patent Document 2 and is described in the multiplexed frame header information (TSMF extension information area) of the multiple TS multiplexed frames. You do n’t have to.

  In order to transmit the TS packet and TS-like packet in a frame having a plurality of predetermined packet placement slots, the multiplex frame header generation unit 13 performs relative processing in the frames related to the TS packet and TS-like packet. Multiplex frame header information including array position information (that is, information indicating the stream type) for indicating the array position is generated and sent to the multiplexing unit 12. Although the multi-frame header information according to the present invention will be described in detail later, the above-described array position information is used as the data structure array for the data structure array information based on the slot array in the existing multiple TS multiple frames (TSMF). The information is extended to be described in the extended information area. However, when the configuration is such that the TS packet and the third packet can be discriminated as the default stream identification information described in the TSMF, it is not always necessary to describe the arrangement position information in the extension information area of the TSMF. That is, it is not necessary to use the extension information area of the TSMF as information for multiplexing or demultiplexing the variable-length packet into the TSMF.

  Multiplexer 12 arranges one multiframe header information slot in one frame, inputs TS packets and TS-like packets output from variable length packet divider 11, and receives multiple frames header generator 13. Based on the data structure indicated by the supplied multiplex frame header information, TS packets and TS-like packets are arranged and multiplexed for each packet allocation slot of the one frame, and a plurality of slots are added by adding the slots of the multiplex frame header information. This is configured as a TS multiplexed frame, and the multiplexed signal of the plurality of TS multiplexed frames is output to the transmitter 14.

  The transmission unit 14 performs predetermined coding modulation on the multiplexed signal of the multiple TS multiplexed frames obtained from the multiplexing unit 12 and transmits the resultant signal as a carrier wave to the outside. For example, a carrier wave (multiplexed signal) based on a plurality of TS multiplexed frames (TSMF) is distributed to a cable television subscriber's home through a cable television transmission path.

  Here, in the technique of Patent Document 2, all the information regarding the head position of the variable-length packet in the TS-like packet is included in the header information of the multiple TS multiplexed frame. The apparatus 10 is different in that the newly defined head position information according to the present invention is accommodated in the TS-like packet by the functions of the variable length packet division unit 11 and the multiple frame header generation unit 13.

  More specifically, the technique of Patent Document 2 is based on a data structure indicated by header information of a plurality of TS multiplexed frames including information on the start position of a variable-length packet and arrangement position information (that is, information indicating the stream type). In addition, the transmission apparatus 10 according to the present invention is configured to form a TS-like packet that encapsulates the divided variable-length packet data. However, in the transmission apparatus 10 according to the present invention, the arrangement position information and / or the TS packet and the third packet The stream identification information configured to be able to discriminate the packet is defined by the multi-frame header information, and the data of the divided variable-length packet is encapsulated based on the data structure indicated by the multi-frame header information. The newly defined head position information related to is stored in the TS-like packet without being described in the multi-frame header information. It differs in that configured to transmit to.

  As described above, according to the transmission device 10 according to the present invention, for the information for dividing or restoring the variable-length packet, the newly defined head position information is transmitted in the TS-like packet. Reduce the amount of information stored in the extended information area, reduce overhead as the transmission efficiency required for multiplex transmission, improve the efficiency of using multiplex frame header information, and efficiently multiplex transmit variable-length packets Is possible.

  FIG. 7 shows an example of division in the variable length packet division unit 11. In the example shown in FIG. 7, the variable length packet dividing unit 11 divides the input variable length packet # 1 into 186 bytes of data from the beginning. This is encapsulated in a TS-like packet # 1 having a length of 188 bytes, in which a synchronization byte (0x47) of 1 byte is added to the head and head position information (1 byte) is added to the second byte, and is supplied to the multiplexing unit 12.

  Next, the variable length packet dividing unit 11 calculates the remaining length of the variable length packet # 1 from the packet length information stored in the variable length packet # 1. If the length of the remaining variable length packet is “186 bytes or more”, 186 bytes of data are divided, a synchronization byte (0x47) is added to the head, and the head position of the variable length packet is set to the second byte. It is encapsulated in a TS-like packet # 2 to which a value (for example, 255) indicating that it is not included is added. When the length of the remaining variable-length packet is “less than 186 bytes”, as with the TS-like packet # 1, a 1-byte synchronization byte (0x47) is added to the head, and head position information is added to the second byte. A TS-like packet to which (1 byte) is added is assumed.

  In the example shown in FIG. 7, the value of the head position information of the variable length packet is “0” indicating the second byte counted from the synchronization byte (0x47) of the first TS-like packet # 1, the second “255” indicating that the TS-like packet # 2 does not include the head position, “X-2” indicating the X byte of the third TS-like packet # 3, and the fourth TS-like packet # 2. “Y-2” representing the 4th Y byte. Here, X-2 is the length of the data that is divided into variable-length packet # 1 and placed in TS-like packet # 3, and Y-2 is the variable length packet # 2 that is divided into TS-like packet # 3. 4 is the length of data to be arranged.

  Note that the technique of Patent Document 2 is configured such that 8 bits indicating information on the head position of a variable-length packet are assigned to each packet placement slot in the frame in the header information of a plurality of TS multiplexed frames. In this case, it is necessary to secure an extended information area describing 416 bits (52 slots × 8 bits) in the header information. On the other hand, in the technique according to the present invention, information related to the head position of the variable length packet is stored in the TS-like packet as head position information according to the present invention. There is no need to newly write information to the extended information area.

  An example of the multiple TS multiplex frame (TSMF) in the transmission apparatus 10 in the second embodiment is configured in the same manner as in FIG. The multiple TS multiplex frame (TSMF) has a slot for storing multiplex frame header information according to the present invention and 52 packet placement slots for assigning TS-like packets and TS packets, and the slot length is 188 bytes. .

  FIG. 8 shows an example of multiframe header information according to the present invention. First, in the data structure arrangement information in the frame of TS packets at the time of multiple TS transmission that is currently operated in compliance with the Japanese CATV Technology Association standard, the correspondence between the TS identifier (ts_id) and the original network identifier (original_network_id) Is given as a relative TS number (relative_ts_number; maximum value 15). The relative TS number indicates the relative TS number of the TS packet stored in each packet placement slot of the frame. The data structure arrangement information is given by using the relative TS number to indirectly correspond to the order of the table of ts_id / original_network_id.

  Therefore, in the transmission apparatus 10 of the present embodiment, the data structure arrangement information of the existing multiple TS multiplexed frames is expanded, and a new TS-like packet and TS packet are arranged for each packet arrangement slot in the frame. In order to obtain data structure array information, array position information (stream type information) indicating whether a stream is a TS packet for each ts_id / original_network_id or whether a stream is a TS-like packet for each TLV_id / original_network_id ) Is newly added to the extension information area in the header information of the TSMF.

  However, if the stream identification information (ts_id / original_network_id and TLV_id / original_network_id) is configured so that it can be determined whether the identifier is a TS identifier (ts_id) or a variable-length packet identifier (eg, TLV_id), the array Position information (stream type information) can be omitted from the multiplexed frame header information (TSMF header).

[Receiver]
FIG. 9 is a schematic configuration diagram of a receiving device 20 according to the second embodiment of the present invention. The receiving device 20 is a device that receives variable-length packet data from a multiplexed signal of TS packet sequences having header information in the TS packet format. The receiving device 21, the separating unit 22, the variable-length packet restoring unit 23, Is provided. As will be apparent from the following description, the receiving device 20 of the present embodiment is different from the functional block of the receiving device disclosed in Patent Document 2 as functions of the separation unit 22 and the variable length packet restoration unit 23. Keep in mind.

  The receiving unit 21 receives and demodulates a carrier wave (multiplexed signal) of a packet sequence transmitted in a plurality of TS multiplexed frames having TS packet format header information as multiplexed frame header information according to the present invention illustrated in FIG. , And sent to the separation unit 22. In particular, since the same synchronization pattern is given to the TS packet and the TS-like packet, the receiving unit 21 can receive these packets as the same packets of the multiple TS multiplexed frames.

  The separation unit 22 extracts and separates TS packets and TS-like packets from a plurality of TS multiplexed frames based on the multiplexed frame header information. More specifically, the separation unit 22 obtains arrangement position information for indicating a relative arrangement position in the frame regarding the TS packet and the TS-like packet having the same packet length as the TS packet from the multiplexed frame header information. The TS-like packet is extracted from the TSMF packet sequence based on the arrangement position information, and the TS-like packet is sent to the variable-length packet restoration unit 23. However, if the TS packet and the TS-like packet are configured to be discriminated by the stream identification information (ts_id / original_network_id and TLV_id / original_network_id) that is information for identifying the stream to which the data of each packet belongs, Since it is not necessary to describe the array position information in the multiplexed frame header information, the separating unit 22 separates the TS position and the TS-like packet from the multiplexed signal of the multiple TS multiplexed frames. The TS-like packet can be discriminated and separated from one or both of the stream identification information and the stream identification information.

  The variable-length packet restoration unit 23 extracts, from the variable-length packet data, the start position information that is information for indicating the start position of the variable-length packet stored in the TS-like packet. In the TS-like packet having the head position and the TS-like packet having the head position, the head position of the variable-length packet is grasped, and data is extracted from the packet sequence of the TS-like packet based on the head position information of the variable-length packet. Combine and restore the variable length packet.

  As described above, in the receiving device 20, the receiving unit 21 demodulates the received carrier wave, extracts a plurality of TS multiplexed frames, and outputs them to the demultiplexing unit 22. In the demultiplexing unit 22, the array stored in the multiframe header information A TS packet and a TS-like packet are separated based on position information and / or stream identification information. The separated TS-like packet is supplied to the variable length packet restoration unit 23. The variable length packet restoring unit 23 combines the data of the packet sequence of the TS-like packet based on the head position information stored in the TS-like packet to restore the variable length packet.

  Here, in the technique of Patent Document 2, the data of the TS-like packet is separated from the TSMF packet sequence based on the arrangement position information stored in the multiframe header information and the information on the start position of the variable length packet. However, in the receiving apparatus 20 according to the present invention, the arrangement position information and / or the stream identification information is obtained by the functions of the separation unit 22 and the variable length packet restoration unit 23. The TS-like packet is separated from the TSMF packet sequence based on the TS-like packet, and the head position information stored in the TS-like packet is extracted, so that the TS-like packet packet data is based on the head position information. In that the variable length packet is restored.

  As described above, according to the receiving device 20 according to the present invention, the head position of the variable-length packet in the TS-like packet can be immediately grasped while the amount of information of the multiframe header information is reduced. It is possible to efficiently restore the variable length packet based on the head position information of the variable length packet in the TS-like packet.

  Therefore, according to the transmission system of the transmission device 10 and the reception device 20 according to the present invention, the variable length packet is encapsulated into a packet of a format with a small overhead of the TS packet length, and the variable length packet is multiplexed simultaneously with the TS packet. Therefore, transmission can be efficiently performed while sharing the transmission equipment even in the configuration of the transmission path. In particular, since information for dividing or restoring variable-length packets is transmitted in TS-like packets, it is efficiently variable while reducing overhead as transmission efficiency and improving utilization efficiency of multiframe header information. Long packets can be multiplexed and transmitted.

  For example, it is possible to construct a transmission system that can multiplex variable-length packets with TSMF simultaneously with TS packets by using a transmission path of a currently used TSMF transmission method. Furthermore, in this transmission system, the amount of information stored in the extension information area of the TSMF required for information required for multiplexing or demultiplexing variable-length packets into the TSMF can be reduced as compared with the technique of Patent Document 2. Therefore, it is possible to secure an area for extended information that can be used to realize a new service in the future.

  Although the above embodiments and examples have been described based on specific examples, various applications are possible. For example, any type of packet may be used as long as it is a variable-length packet having packet length information. The transmitting side divides and multiplexes into a plurality of TS multiplexed frames (TSMF) in the same manner as described above, and the receiving side receives the received carrier A variable-length packet can be restored from (multiplexed signal). Although IP packets and GSE packets can be directly encapsulated in TS-like packets, IP packets are once encapsulated in TLV packets and then encapsulated from TLV packets into TS-like packets as described above. You may comprise.

  Moreover, it can be set as the aspect which combined 1st Embodiment and 2nd Embodiment as application of each above-mentioned embodiment and an Example. For example, in the second embodiment, each TS-Like packet can be identified to indicate whether or not the beginning position of a variable-length packet is included, and indicates whether or not the beginning position of this variable-length packet is included. The effect corresponds to the flag in the first embodiment. Therefore, as a modification of the first embodiment, instead of inserting a flag indicating whether or not the beginning position of the variable-length packet is included in the multiframe header information, it is inserted in the header of the TS-Like packet. Also good.

  According to the present invention, since it is possible to efficiently transmit variable-length packets such as IP packets simultaneously with transmission of digital broadcasting TS, it is useful for the use of a transmitter and a receiver that use variable-length packets. It is. In particular, according to the present invention, it is possible to reduce the amount of information stored in the extension information area of TSMF for transmitting information necessary for multiplexing or demultiplexing variable-length packets to TSMF. This is useful for information transmission using frames.

DESCRIPTION OF SYMBOLS 10 Transmitting device 11 Variable length packet dividing unit 12 Multiplexing unit 13 Multiple frame header generating unit 14 Transmitting unit 20 Receiving device 21 Receiving unit 22 Separating unit 23 Variable length packet restoring unit

Claims (2)

A transmission apparatus that multiplex-transmits a variable-length packet in a frame composed of a plurality of packet placement slots to which TS (Transport Stream) packets are allocated and one multi-frame header information slot,
Generate a third packet having the same packet length as the TS packet to be transmitted, divide the variable length packet to be transmitted, and sequentially assign the divided variable length packet data to the third packet, The same synchronization byte as that of the TS packet is added to the received data, and the head position information indicating the head position of the variable length packet is added to the data located at the head position of the variable length packet. Variable-length packet dividing means for forming a packet sequence of a third packet;
Multiplex frame header generation means for generating multiplex frame header information defining a data structure arrangement of the TS packet and the third packet in a frame having a plurality of predetermined packet placement slots;
A multiplexing unit configured to arrange and multiplex the TS packet and the third packet for each packet arrangement slot based on the multiplex frame header information, and configure a plurality of TS multiplex frames;
Transmission means for transmitting the multiplexed signal of the plurality of TS multiplexed frames to the outside,
A flag for distinguishing whether or not to include the start position of the variable length packet is included in the third packet, and the start position information of the variable length packet is included in the multiplexed frame header information. It is configured without being included, and is arranged only when the flag indicates that the leading position of the variable length packet is included in the third packet, and the leading position information to be arranged is the leading position of the variable length packet Is described in 1 byte as a numerical value indicating the position in the third packet,
The multi-frame header generation means includes means for generating the multi-frame header information so as to include arrangement position information for indicating a relative arrangement position in a frame related to the TS packet and the third packet. A transmission device characterized. Receives variable-length packet data from a multiplexed signal of multiple TS multiplexed frames in which variable-length packet data is multiplexed in a frame consisting of a plurality of packet placement slots to which TS packets are allocated and one multi-frame header information slot A receiving device,
Receiving means for receiving a multiplexed signal of the plurality of TS multiplexed frames;
Separating means for extracting and separating a third packet including data of the variable-length packet from the plurality of TS multiplexed frames with reference to the multiplexed frame header information of the plurality of TS multiplexed frames;
Extracting the head position information of the variable length packet stored in the third packet, extracting the data from the packet sequence of the third packet based on the head position information of the variable length packet, and combining the variable Variable length packet restoring means for restoring long packets,
A flag for distinguishing whether or not to include the start position of the variable length packet is included in the third packet, and the start position information of the variable length packet is included in the multiframe header information And is arranged only when the flag indicates that the leading position of the variable length packet is included in the third packet, and the leading position information to be arranged is any of the third packets. A numerical value indicating whether it is in a position is described in 1 byte,
The multi-frame header information includes arrangement position information for indicating a relative arrangement position in a frame related to the TS packet and the third packet, and the separation unit refers to the arrangement position information, and Means for separating the third packet from a plurality of TS multiplex frames;
The variable length packet restoring means extracts the head position information of the variable length packet stored in the third packet with reference to the flag, and based on the numerical value indicated by the head position information, the variable length packet A receiving apparatus characterized by determining a head position of the receiver.