JP6478153B2 - Data transmission system, receiving apparatus, and program - Google Patents

Description

  The present invention relates to a data transmission system, a receiving device, and a program.

  Currently, in digital broadcasting, data broadcasting content is transmitted using a data carousel transmission system (see Non-Patent Document 1) so that all files constituting the data broadcasting content can be received even if data reception is started halfway. The file to be configured is being transmitted. This data carousel transmission system is a system premised on transmission in MPEG2-TS. On the other hand, in future digital broadcasting for Super Hi-Vision and the like, it is decided that MMT (Mpeg Media Transport; ISO / IEC 23008-1) will be adopted as a transmission method. Is transmitted in an MMTP (Mpeg Media Transport Protocol) packet.

“Data Broadcast Coding and Transmission Standards for Digital Broadcasting Standard ARIB STD-B24 Version 5.8 (Third Volume)”, Japan Radio Industry Association, July 2013

  However, the MMT transmission has a problem that there is no transmission method that can receive all content files whenever the receiver starts data reception.

  The present invention has been made in view of such circumstances, and in MMT transmission, a data transmission system, a receiving apparatus, and a data transmission system capable of receiving all files whenever data reception starts. And provide programs.

(1) The present invention has been made to solve the above-described problems. According to one aspect of the present invention, a file constituting a content is acquired, and an MMTP packet storing the file constituting the content is repeatedly transmitted. Data sending device, control message generating device for sending an MMTP packet storing a table for storing the path name of each file constituting the content, MMTP packet sent by the data sending device, and the control message generating device The packet ID of the MMTP packet storing the file constituting the content is different from the packet ID of the MMTP packet storing the table. A data transmission system.

(2) According to another aspect of the present invention, there is provided the data transmission system according to (1), in which the data transmission device acquires a file constituting the content, and the file acquisition unit Repeatedly stores the MMTP payload generation unit that stores the obtained file in the MMTP payload, the payload storage unit that stores the MMTP payload, and the MMTP payload that the payload storage unit stores in the MMTP packet And a sending unit.

(3) Another aspect of the present invention is the data transmission system according to (1) or (2), wherein the table is a data directory management table.

(4) According to another aspect of the present invention, an MMTP packet storing a file constituting a content and a table storing a path name of each file constituting the content are repeatedly sent. And a file restoration unit that restores a file with a desired path name from the MMTP packet received by the reception unit with reference to the table, and stores the files that constitute the content The receiving apparatus is characterized in that the packet ID of the MMTP packet is different from the packet ID of the MMTP packet storing the table.

(5) Further, according to another aspect of the present invention, a computer stores a MMTP packet storing a file constituting a content, which is repeatedly transmitted, and a table storing a path name of each file constituting the content. A receiving unit for receiving an MMTP packet, a program for referring to the table and for causing a function to function as a file restoring unit for restoring a file having a desired path name from an MMTP packet received by the receiving unit, The packet ID of the MMTP packet that stores the file that constitutes the file is different from the packet ID of the MMTP packet that stores the table.

  According to the present invention, in the MMT transmission, all files can be received whenever data reception is started.

1 is a schematic block diagram showing a configuration of a content transmission system 10 according to an embodiment of the present invention. It is a schematic diagram which shows the structural example of the IP data flow which the broadcasting equipment 11 in the embodiment transmits. It is a schematic diagram explaining the transmission method of the file by the broadcasting equipment 11 in the embodiment. It is a schematic block diagram which shows the structure of the broadcast equipment 11 in the embodiment. It is a schematic block diagram which shows the structure of the control message production | generation apparatus 101 in the embodiment. It is a schematic block diagram which shows the structure of the data transmission apparatus 104 in the embodiment. It is a schematic block diagram which shows the structure of the receiver 12 in the same embodiment. It is a table | surface which shows the data structure of the data transmission message in the same embodiment. It is a table | surface which shows the data structure of the data directory management table in the embodiment. It is a table | surface which shows the data structure of the transmission arrangement information in the same embodiment. It is a table | surface which shows the data structure of the data asset management table in the embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing a configuration of a content transmission system 10 according to an embodiment of the present invention. The content transmission system 10 transmits content composed of one or more files (also referred to as multimedia content) using broadcast waves. The content transmission system 10 transmits the data by the MMT (MPEG Media Transport) method using TLV (Type Length Value) and IP (Internet Protocol) in order from the lower layer as a transmission data format.

  The content transmission system 10 includes a broadcast facility 11, a receiving device 12, and an output device 13. The broadcast facility 11 repeatedly sends out the files that make up the content using broadcast waves. This file includes character information such as HTML (HyperText Markup Language) files, files including control information, files describing applications such as JavaScript (registered trademark), still image files such as JPEG (Joint Picture Experts Group), Audio files such as MPEG-2 audio can be included. The receiving device 12 receives a file distributed by the broadcasting facility 11, and generates an image and sound of the content by rendering, executing, and decoding the received file. The receiving device 12 generates an image signal representing the image of the content and an audio signal representing the sound, and inputs them to the output device 13. The output device 13 includes a display device such as a liquid crystal display and a speaker, and displays an image represented by the image signal generated by the receiving device 12 and outputs a sound represented by the audio signal. Note that the receiving device 12 and the output device 13 may be integrated.

  FIG. 2 is a schematic diagram illustrating a configuration example of an IP data flow transmitted by the broadcasting facility 11. In FIG. 2, one package P1 is transmitted in the IP data flow DF1 distributed from the broadcasting facility 11. In one package P1, a data transmission message (Data_Transmission_Message) DTM1 (data transmission information) and a plurality of data assets DA1 and DA2 are transmitted. The data transmission message DTM1 is a message defined by MMT, and in this embodiment, “0x8002” is used as the message ID. Data assets DA1 and DA2 are assets defined by MMT that transmit files constituting content as items I1, I2,. Each asset is a bit stream stored in an MMTP packet having a specific packet ID (packet_id), and is also referred to as a component.

  The data transmission message DTM1 stores a data directory management table (Data_Directory_Management_Table) DM1 (directory management information) and data asset management tables (Data_Asset_Management_Table) AM1 and AM2 (asset management information). The data directory management table DM1 associates a path name of a file that constitutes content with an item ID (file identification information) of the file. The item ID is information that identifies a file constituting the content in the data flow in combination with the packet ID or the asset ID. In addition to these, the data directory management table DM also associates an IP data flow and a packet ID, but description thereof is omitted here. The correspondence between the asset ID and the packet ID is described in the MP table in the PA message that is a kind of control message.

  Each of the data asset management tables AM1 and AM2 stores one corresponding asset ID and an item ID of a file stored in the data asset of the asset ID. As many data asset management tables as data assets are stored in the data transmission message.

  Therefore, when a file path name is given, the item ID of the file is obtained from the data directory management table DM1. Further, the asset ID is obtained from the data asset management table AM1 storing the obtained item ID. The item with the obtained item ID transmitted by the data asset with the asset ID is a file given a path name.

  FIG. 3 is a schematic diagram for explaining a file transmission method by the broadcasting facility 11. As shown in FIG. 3, the broadcasting facility 11 divides the file F1 to be transmitted into blocks F1a, F1b,. The broadcast facility 11 adds MMTP payload headers PH1, PH2,... To these blocks F1a, F1b,. These MMTP payload headers PH1, PH2,... Include an item ID, a fragmentation indicator, and a fragment counter (fragment_counter). The item ID is the item ID of the file F1 of the block to which the MMTP payload header is added.

  The fragmentation indicator takes four values from “0” to “3”. “0” indicates that the file is completed only by the block to which the MMTP payload header is added. "1" indicates that the block to which the MMTP payload header is added is the head of the file. “2” indicates that the block to which the MMTP payload header is added is neither the beginning nor the end of the file. “3” indicates that the block to which the MMTP payload header is added is the end of the file. The fragment counter indicates how many MMTPs are divided from the same file.

  The broadcasting facility 11 adds MMTP packet headers H1 and H2 to the payloads PL1, PL2,... To form MMTP packets P1 and P2, respectively. These MMTP packet headers H1 and H2 include a packet ID, a packet sequence number, and a time stamp, respectively. The packet sequence number is a serial number assigned to the same packet ID. The time stamp indicates the time when the first byte of the MMTP packet is transmitted.

  The broadcast facility 11 repeatedly sends out these MMTP packets P1, P2,. However, the broadcasting equipment 11 assigns the value of the packet sequence number and time stamp of the MMTP packet header each time it is sent. For example, the broadcasting facility 11 assigns a value to the packet sequence number so that the packet sequence number is a continuous number from the packet sequence number of the same packet ID sent immediately before.

  The receiving device 12 receives these MMTP packets P1, P2, P3,... And constructs a file F1, a file F2,. At this time, for example, it is assumed that the reception device 12 starts reception from the MMPT packet P3. Since the MMTP packets P1, P2, P3,... Are repeatedly transmitted, the receiving apparatus 12 receives the MMTP packets P1, P2 that are transmitted again after receiving the MMTP packet P3 and subsequent ones. For this reason, the receiving device 12 can receive all of the MMTP packets P1, P2,..., And can construct all the files F1, F2,. The same applies when reception of an MMTP packet on the way fails due to a transmission error or the like.

  FIG. 4 is a schematic block diagram showing the configuration of the broadcast facility 11. The broadcasting facility 11 includes a control message generation device 101, a video transmission device 102, an audio transmission device 103, a data transmission device 104, a multiplexing device 105, and a distribution device 106. The control message generator 101 generates an MMTP packet that stores a data transmission message. The data transmission message associates information indicating the path name of the file constituting the content with information related to the arrangement of the file in the transmission path. This association is performed by the data directory management table and the data asset management table stored in the data transmission message. The control message generator 101 may generate an MMTP packet that stores a control message such as a PA message that stores an MP table.

  The video transmission apparatus 102 generates an MMTP packet storing video assets. The audio transmission device 103 generates an MMTP packet storing audio assets. The data transmission device 104 generates an MMTP packet that stores an asset (data asset) that transmits a file constituting the content as an item. The files that make up the content include text information such as HTML files, files containing control information, files that describe applications such as JavaScript (registered trademark), still image files such as JPEG, and audio files such as MPEG-2 audio and so on. Multiplexer 105 multiplexes the MMTP packets generated by control message generator 101, video transmitter 102, audio transmitter 103, and data transmitter 104. The multiplexer 105 generates an IP data flow that transmits the multiplexed MMTP packet. The distribution device 106 (distribution unit) generates a TLV stream that transmits the IP data flow generated by the multiplexing device 105, and distributes the TLV stream using a broadcast wave.

  FIG. 5 is a schematic block diagram showing the configuration of the control message generating apparatus 101. The control message generation device 101 includes a directory management table generation unit 111, an asset management table generation unit 112, and a data transmission message generation unit 113. The directory management table generation unit 111 generates a directory management table that associates the path names of all the files that make up the content with information related to the arrangement of the files in the transmission path.

  In the directory management table, when the file is transmitted by the broadcasting facility 11, the package ID of the package in which the file is transmitted and the item ID associated with the file are used as information regarding the arrangement on the transmission path. Storing. Also, the directory management table stores information about the arrangement on the transmission path even when a file is transmitted by multicast or unicast via the IP network, but the details are omitted.

  The asset management table generation unit 112 generates an asset management table that stores information related to the arrangement in the transmission path of the files constituting the content that are transmitted in the same package as the table. The information related to the arrangement on the transmission path stored in the asset management table is the asset ID of the data asset associated with the asset management table and the item ID of the file stored in the data asset. The data transmission message generation unit 113 generates a data transmission message in which the directory management table generated by the directory management table generation unit 111 and the asset management table generated by the asset management table generation unit 112 are stored.

  FIG. 6 is a schematic block diagram showing the configuration of the data transmission device 104. The data transmission device 104 includes a file acquisition unit 141, an MMTP payload generation unit 142, a payload storage unit 143, an MMTP packet generation unit 144, and a data asset transmission unit 145. The MMTP packet generation unit 144 and the data asset transmission unit 145 function as a transmission unit 146. The file acquisition unit 141 acquires a file constituting the content. The MMTP payload generation unit 142 divides the file acquired by the file acquisition unit 141 into a predetermined size or less, adds an MMTP payload header, and generates an MMTP payload. The MMTP payload generation unit 142 causes the payload storage unit 143 to store the generated MMTP payload.

  The MMTP packet generation unit 144 reads the MMTP payload stored in the payload storage unit 143 and adds an MMTP packet header to the read MMTP payload, thereby generating an MMTP packet. The MMTP packet generation unit 144 repeatedly reads out all the MMTP payloads to be transmitted and generates MMTP packets. At this time, the MMTP packet generation unit 144 assigns values so that the packet sequence numbers in the MMTP packet header are consecutive numbers. When the MMTP packet generation unit 144 generates an MMTP packet, the data asset transmission unit 145 outputs the MMTP packet.

  FIG. 7 is a schematic block diagram illustrating the configuration of the receiving device 12. The reception device 12 includes a broadcast reception unit 201, a separation unit 202, a designation acquisition unit 203, a reception control unit 204, a control message processing unit 205, a video decoding unit 206, an audio decoding unit 207, a data rendering unit 208, a video synthesis unit 209, A speech synthesis unit 210 and a file restoration unit 211 are included. The broadcast receiving unit 201 receives a broadcast wave transmitted from the broadcast facility 11 and detects a TLV stream from the received broadcast wave. The broadcast receiving unit 201 extracts the IP data flow stored in the detected TLV stream and inputs it to the separation unit 202.

  The separation unit 202 extracts an MMTP packet from the input IP data flow. The separation unit 202 inputs the MMTP packet having the packet ID specified by the reception control unit 204 to the control message processing unit 205, the video decoding unit 206, the audio decoding unit 207, and the file restoration unit 211, respectively. The designation obtaining unit 203 obtains content designation by the user. In the present embodiment, the content is specified by pressing a button corresponding to the package ID of the package that transmits the content using the remote controller of the receiving device 12. The designation acquisition unit 203 detects the pressed button and inputs a package ID corresponding to the button to the reception control unit 204.

  The reception control unit 204 determines an IP data flow to be received according to the package ID input from the designation acquisition unit 203 and instructs the broadcast reception unit 201 to receive the IP data flow. Also, the reception control unit 204 instructs the packet ID of the MMTP packet input to each unit to the separation unit 202 according to the packet ID of each asset constituting the package input from the control message processing unit 205.

  The control message processing unit 205 extracts a control message such as a data transmission message and a PA message from the MMTP packet input from the separation unit 202. The control message processing unit 205 acquires the packet ID of the asset constituting the package from the PA message and inputs it to the reception control unit 204. In addition, the control message processing unit 205 acquires the correspondence between the path name of the file constituting the content and the item ID from the data transmission message, and inputs it to the file restoration unit 211.

  The video decoding unit 206 extracts and decodes video data stored in the MMTP packet input from the separation unit 202. The video decoding unit 206 inputs the video signal obtained by decoding to the video synthesis unit 209. The audio decoding unit 207 extracts and decodes audio data stored in the MMTP packet input from the separation unit 202. The audio decoding unit 207 inputs the audio signal obtained by decoding to the audio synthesis unit 210. The data rendering unit 208 is, for example, an HTML browser, and renders, executes, and decodes the file restored by the file restoration unit 211 to generate an image signal and an audio signal. Since the file restored by the file restoration unit 211 is a file sent by the data sending device 104, a file containing character information such as an HTML file, control information, etc., and an application such as JavaScript (registered trademark) are described. Files, still image files such as JPEG, and audio files such as MPEG-2 audio are included.

  The video synthesis unit 209 synthesizes the video signal from the video decoding unit 206 and the video signal from the data rendering unit 208 and outputs the synthesized video signal. The voice synthesis unit 210 synthesizes the voice signal from the voice decoding unit 207 and the voice signal from the data rendering unit 208 and outputs the synthesized voice signal.

  The file restoration unit 211 restores a file from the MMTP packet input from the separation unit 202. For example, as shown in FIG. 3, if the file is divided into MMTP packets P1, P2, P3,... And repeatedly sent out, the file restoration unit 211 starts the reception from the MMTP packet P3. MMTP packets P1 and P2 can be received by repeating the above and the file can be restored. The file restoration unit 211 refers to the correspondence between the path name input from the control message processing unit 205 and the item ID, and identifies the path name of the restored file. The file restoration unit 211 inputs a file having a path name designated by the data rendering unit 208 to the data rendering unit 208.

  FIG. Is a column indicating the serial number of the row in the table. The data structure is a column indicating the data structure of the data transmission message. The number of bits is a column indicating the number of bits of the data structure. The bit string notation is a column indicating the data format of the data structure of the number of bits. Uimsbf in bit string notation is an abbreviation for unsigned integer most significant bit first, and an unsigned integer and the most significant bit mean the head.

  In FIG. 1 “Data_Transmission_message () {” will be referred to as “No. Up to 14 “}” represents the data structure of the data transmission message. No. placed at the top of the message. 2, “message_id” is a 16-bit area indicating an ID (Identifier) of the data transmission message, and “0x8002” is set in the present embodiment. Next No. is arranged. “Version” of 3 is an 8-bit area indicating the version number of the data transmission message. Next No. “Length” of 4 is a 32-bit area indicating the number of bytes of the data transmission message after the area.

  Next No. is arranged. “Num_of_tables” of 5 is an 8-bit area indicating the number of tables stored in the data transmission message. The following No. No. 6 “for (i = 0; i <N; i ++) {” is “No. 10 is repeated N times, that is, the number of stored tables (num_of_tables). Next No. is arranged. 7, “table_id” is an 8-bit area indicating the ID of the table stored in the data transmission message. The value of this area is the same as the value of “table_id” arranged at the head of each table.

  Next No. is arranged. “Table_version” of No. 8 indicates the previous No. 7 is an 8-bit area indicating the version number of the table indicated by the table ID 7. The value in this area is the same as the “version” value in the table. Next No. “Table_length” of No. 9 indicates the previous No. 7 is a 16-bit area indicating the length of the table indicated by the table ID 7. The value of this area is the same as the “length” value of the table. The following No. No. 10 “}” indicates no. 6 corresponds to “{”.

  The following No. No. 11 “for (i = 0; i <N; i ++) {” is hereinafter referred to as “}”. 13 is repeated N times, that is, the number of stored tables (num_of_tables). The following No. “Table ()” of 12 indicates that one table is stored.

  FIG. 9 is a table showing the data structure of the data directory management table. In the table, no. Is a column indicating the serial number of the row in the table. The data structure is a column indicating the data structure of the data directory management table. The number of bits is a column indicating the number of bits of the data structure. The bit string notation is a column indicating the data format of the data structure of the number of bits. Uimsbf in bit string notation is an abbreviation for unsigned integer most significant bit first, and an unsigned integer and the most significant bit mean the head. Further, char in the bit string notation means a character.

  In FIG. 1 “Data_Directory_Management_Table () {” will be referred to as “No. Up to 33 “}” represents the data structure of the data directory management table. No. placed at the top of the table. 2, “table_id” is an 8-bit area indicating the ID of the data directory management table. In this embodiment, “0x87” is used as the ID of the data directory management table. Next No. “Version” 3 is an 8-bit area indicating the version number of the data directory management table. Next No. is arranged. “Length” of 4 is a 16-bit area indicating the number of bytes of the data directory management table after the area.

  Next No. 5 “list_scheme” is “No. This is a 32-bit area that specifies up to 32 data structures. When the value of “list_scheme” is “1”, it indicates that the correspondence between the path name of the file and the information related to the arrangement on the transmission path is stored in the external file. When the value of “list_scheme” is “2”, this indicates that the association is directly described in this table. The following No. 6 “if (list_scheme == 1) {” No. 5 when the value of “list_scheme” is “1”. 11 indicates that data structures up to “}” are arranged. No. “List_length” arranged in 7 is an 8-bit area indicating the length of reference information (for example, URL) to a file that stores a correspondence between the path name of the file and information related to the arrangement in the transmission path. is there.

  The following No. 8 “for (i = 0; i <list_length; i ++) {” No. 10 “}”. 9 indicates that the data structure of 9 is repeated by “list_length”. No. 9, “list_value” is an 8-bit area indicating reference information to a file that is arranged for “list_length” and stores a correspondence between a path name of the file and information on the arrangement on the transmission path.

  The following No. 12 “if (list_scheme == 2) {” 5 when the value of “list_scheme” of “5” is “2”. This indicates that data structures up to 32 “}” are arranged. Next No. 13 “num_of_files” is an 8-bit area indicating the number of files constituting the content, that is, the number of files in which information is stored in the data directory management table. The following No. 14 “for (j = 0; j <M; j ++) {” The data structure up to 30 “}” is repeatedly arranged by the value of “num_of_files”.

  Next placed No. 15, “Transport_location_info ()” is an area of transmission arrangement information for designating an IP data flow, a package, etc., among information on arrangement on the transmission path. Details of the transmission arrangement information will be described later. Hereinafter, no. The files shown up to 25 are arranged in the transmission path designated by this transmission arrangement information. Next placed No. 16 “location_type” is an 8-bit area indicating the type of transmission path. The following No. 17 “if (location_type == 0x00 || 0x01 || 0x02) {” 16 when the value of “location_type” is “0x00”, “0x01”, or “0x02”. 18 data structures are arranged. No. 18 “item_ID” is a 32-bit area indicating a value of an item ID for identifying a file distributed from the broadcasting facility 11 in the package.

  The following No. 19 "} else {" 16 when the value of “location_type” is not “0x00”, “0x01”, or “0x02”. 21 indicates that the data structure up to “}”, that is, No20 is arranged. No. 20 “transport_file_ID” is a 32-bit area indicating a value of a file ID for identifying a file distributed from the distribution facility 12 by IP multicast in a data flow by the IP multicast.

  Next No. 22 “file_directory_length” is an 8-bit area indicating the length of the path name of the file. The next “for (k = 0; k <file_directory_length; k ++) {” No. 25 “}”, that is, no. It shows that 24 data structures are arranged for “file_directory_byte”. No. 24 “file_directory_byte” is an 8-bit area indicating the path name of the file, which is arranged for “file_directory_length”. Next placed No. 26 “descriptor_loop_length” is a 16-bit area indicating the number of descriptors to be arranged thereafter. The following No. 27, “for (l = 0; l <N; l ++) {” No. 29 “}”, that is, no. This indicates that 28 data structures are repeated by “descriptor_loop_length”. No. 28 “descriptor ()” is an area for arranging an arbitrary descriptor (descriptor).

  FIG. 10 is a table showing a data structure of the transmission arrangement information. In the table, no. Is a column indicating the serial number of the row in the table. The data structure is a column indicating the data structure of the transmission arrangement information. The number of bits is a column indicating the number of bits of the data structure. The bit string notation is a column indicating the data format of the data structure of the number of bits. Uimsbf in bit string notation is an abbreviation for unsigned integer most significant bit first, and an unsigned integer and the most significant bit mean the head. Further, char in the bit string notation means a character.

  No. “Transport_location_info () {” of No. 1 Up to 34 “}” indicates the data structure of the transmission arrangement information. Next placed No. 2 "location_type" is an 8-bit area indicating the type of transmission path. The following No. 3 “if (location_type == 0x00) {” 2 when the value of “location_type” of “2” is “0x00”. 5 indicates that data structures up to “}” are arranged. When the value of “location_type” is “0x00”, the file is transmitted in the MMTP packet transmitted in the IP data flow in which the transmission arrangement information is transmitted. No. “Packet_id” arranged in 4 is a 16-bit area indicating the packet ID of the MMTP packet.

  The following No. “If (location_type == 0x01) {” in No. 6 No. 2 when the value of “location_type” is “0x01”. 11 indicates that data structures up to “}” are arranged. When the value of “location_type” is “0x01”, the file is transmitted in the MMTP packet transmitted in the IP data flow by the IPv4 IP multicast. Next No. is arranged. 7 “ipv4_src_addr” is a 32-bit area indicating the source address of the IP data flow. Next No. 8, “ipv4_dst_addr” is a 32-bit area indicating the multicast address (destination address) of the IP data flow. Next No. “Dst_port” 9 is a 16-bit area indicating the destination port number of the IP data flow. Next No. 10 “packet_id” is the packet ID of the MMTP packet.

  The following No. No. 12 “if (location_type == 0x02) {” 2 when the value of “location_type” of “2” is “0x02”. 17 indicates that data structures up to “}” are arranged. When the value of “location_type” is “0x02”, the file is transmitted in the MMTP packet transmitted in the IP data flow by the IPv6 IP multicast. Next No. is arranged. 13 “ipv6_src_addr” is a 128-bit area indicating the source address of the IP data flow. Next No. is arranged. 14 “ipv6_dst_addr” is a 128-bit area indicating the multicast address (destination address) of the IP data flow. Next No. 15 “dst_port” is a 16-bit area indicating the destination port number of the IP data flow. Next No. 16 “packet_id” is the packet ID of the MMTP packet.

  The following No. No. 18 “if (location_type == 0x03) {” 2 when the value of “location_type” is “0x03”. 22 indicates that data structures up to “}” are arranged. When the value of “location_type” is “0x03”, the file is transmitted in an IP data flow based on IPv4 IP multicast. Next No. is arranged. 19 “ipv4_src_addr” is a 32-bit area indicating the source address of the IP data flow. Next No. 20 “ipv4_dst_addr” is a 32-bit area indicating the multicast address (destination address) of the IP data flow. Next No. “Dst_port” 21 is a 16-bit area indicating the destination port number of the IP data flow.

  The following No. 23, “if (location_type == 0x04) {” 2 when the value of “location_type” of “2” is “0x04”. 27 indicates that data structures up to “}” are arranged. When the value of “location_type” is “0x04”, the file is transmitted in the IP data flow by the IPv6 IP multicast. Next No. 24 “ipv6_src_addr” is a 128-bit area indicating the source address of the IP data flow. Next No. 25 “ipv6_dst_addr” is a 128-bit area indicating the multicast address (destination address) of the IP data flow. Next No. 26 “dst_port” is a 16-bit area indicating the destination port number of the IP data flow.

  The following No. 28, “if (location_type == 0x05) {” 2 when the value of “location_type” of “2” is “0x05”. This indicates that data structures up to 33 “}” are arranged. When the value of “location_type” is “0x05”, the file is transmitted by unicast. Next No. 29 “URL_length” is an 8-bit area indicating the length of the URL of the file. The following No. 30 “for (i = 0; i <N; i ++) {” 32 “}”, ie, No. 32. This indicates that 31 data structures are arranged for “URL_length”. No. “URL_byte” 31 is an 8-bit area indicating the URL arranged by “URL_length”.

  FIG. 11 is a table showing the data structure of the data asset management table. In the table, no. Is a column indicating the serial number of the row in the table. The data structure is a column indicating the data structure of the data asset management table. The number of bits is a column indicating the number of bits of the data structure. The bit string notation is a column indicating the data format of the data structure of the number of bits. Uimsbf in bit string notation is an abbreviation for unsigned integer most significant bit first, and an unsigned integer and the most significant bit mean the head. Further, char in the bit string notation means a character.

  In FIG. 1 “Data_Asset_Management_Table () {” will be referred to as “No. 27 to “}” represents the data structure of the data asset management table. No. placed at the top of the table. “Table_id” of 2 is an 8-bit area indicating the ID of the data asset management table. In this embodiment, “0x88” is used as the ID of the data asset management table. Next No. “Version” of 3 is an 8-bit area indicating the version number of the data asset management table. Next No. “Length” of 4 is a 16-bit area indicating the number of bytes of the data directory management table after the area.

  Next No. “Asset_ID_scheme” 5 is a 32-bit area indicating the scheme (description format) of the asset ID (asset_ID). Next No. is arranged. “Asset_ID_length” of 6 is an 8-bit area indicating the length (number of bytes) of the asset ID. The following No. 7 “for (i = 0; i <asset_ID_length; i ++) {” No. 9 “}”, ie, No. 9 8 data structure No. 8 This indicates that repetition is performed for “asset_ID_length” of six. Next No. is arranged. “Asset_ID_byte” of 8 is an 8-bit area that is arranged for “asset_ID_length” and indicates an asset ID. This asset ID indicates which data asset information is stored in the data asset management table.

  Next No. is arranged. “Num_of_item” of No. 10 This is an 8-bit area indicating the number of items stored in the data asset having the asset ID of 8. The following No. 11 “for (j = 0; j <M; j ++) {” 14 data structure. It indicates to repeat 10 “num_of_item”. Next No. is arranged. 12 “item_ID” is a 32-bit area indicating an item ID. This item ID is No. This is the item ID of the file stored in the data asset with the asset ID of 8. Next No. 13 “item_version” is the last No. This is an 8-bit area indicating the version number of the file indicated by 12 “item_ID”.

  The following No. 15 “for (j = 0; j <M; j ++) {” No. 22 data structure It indicates to repeat 10 “num_of_item”. Next No. is arranged. 16 “item_ID” is a 32-bit area indicating an item ID. No. immediately after Data having a data structure up to 21 is data relating to the file indicated by the item ID. Next No. 17 “item_checksum” is a 32-bit area indicating a checksum of a file. For this checksum, for example, a cyclic redundancy check (CRC) is used.

  Next No. is arranged. “Item_location_length” of No. 18 indicates the previous No. This is a 32-bit area indicating the length (number of bytes) of the path name of the file indicated by 16 “item_ID”. The following No. 19 “for (k = 0; k <item_location_length; k ++) {” No. 21, that is, no. No. 20 data structure is No. It indicates that 18 items are repeated for “item_location_length”. Next No. 20 “item_location_byte” is an 8-bit area indicating a path name by being repeatedly arranged for “item_location_length”.

  Next placed No. 23, “descriptor_loop_length” is a 16-bit area indicating the number of descriptors arranged immediately after. The following No. 24, “for (l = 0; l <N; l ++) {” No. 23 “descriptor_loop_length”, No. 23 No. 26 “}”, that is, no. This indicates that 25 data structures are repeatedly arranged. Next No. is arranged. 25 “descriptor ()” indicates that a descriptor is arranged.

  In this embodiment, the IP data flow is transmitted by the MMT multiplexing method, but the present invention is not limited to this. For example, it may be transmitted on an IP network, or may be transmitted by another bit stream transmitted by a broadcast wave. Further, the TLV stream may be transmitted by a medium other than a broadcast wave such as a cable television.

As described above, the data transmission device 104 acquires a file constituting the content, and repeatedly transmits the MMTP packet storing the file.
The receiving device 12 also includes a broadcast receiving unit 201 that receives an MMTP packet that stores a file that constitutes content, and a file restoring unit 211 that restores a file from the received MMTP packet.
Thereby, in the MMT transmission, it is possible to receive all the files whenever data reception is started.

The data transmission device 104 stores the MMTP payload generation unit 142 that stores the file in the MMTP payload, the payload storage unit 143 that stores the MMTP payload, and the MMTP payload stored in the payload storage unit 143 in the MMTP packet. A sending unit 146 that repeats sending.
This eliminates the need to generate an MMTP payload having the same contents every time when it is repeatedly sent.

In addition, the broadcasting facility 11 (data transmission system) includes a data transmission device 104, a control message generation device 101 that transmits an MMTP packet storing a table that stores the path names of the files that constitute the content, and the data transmission device 104. And a multiplexing device 105 that multiplexes the MMTP packets sent out by the control message generation device 101.
This makes it possible to freely change the combination of rates between the asset that transmits the file and the table that stores the path name of the file.

  Further, the program for realizing the functions of the broadcasting equipment 11 and the receiving device 12 in FIG. 1, the control message generating device 101 and the data sending device 104 in FIG. 4 is recorded on a computer-readable recording medium, and the recording medium is recorded on this recording medium. These apparatuses may be realized by reading a recorded program into a computer system and executing the program. Here, the “computer system” includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 10 ... Content transmission system, 11 ... Broadcasting equipment, 12 ... Receiving device, 13 ... Output device, 101 ... Control message generating device, 102 ... Video sending device, 103 ... Audio sending device, 104 ... Data sending device, 105 ... Multiplexing device , 106 ... distribution device, 111 ... directory management table generation unit, 112 ... asset management table generation unit, 113 ... data transmission message generation unit, 141 ... file acquisition unit, 142 ... MMTP payload generation unit, 143 ... payload storage unit, 144 ... MMTP packet generation unit, 145 ... data asset transmission unit, 146 ... transmission unit, 201 ... broadcast reception unit, 202 ... separation unit, 203 ... designation acquisition unit, 204 ... reception control unit, 205 ... control message processing unit, 206 ... Video decoding unit, 207 ... audio decoding unit, 208 ... data renderer Parts, 209 ... video combining portion, 210 ... voice synthesis unit, 211 ... file restoration unit

Claims (4)

A data sending device that obtains a file constituting the content and repeatedly sends out the MMTP packet storing the file constituting the content;
A control message generating device for sending out an MMTP packet storing a table storing path names of files constituting the content;
A multiplexing device for multiplexing the MMTP packet sent by the data sending device and the MMTP packet sent by the control message generating device;
The packet ID of the MMTP packet storing the file that constitutes the content is different from the packet ID of the MMTP packet storing the table ,
The data transmission system , wherein the table is a data directory management table . The data sending device is
A file acquisition unit for acquiring files constituting the content;
An MMTP payload generation unit that stores the file acquired by the file acquisition unit in an MMTP payload;
A payload storage unit for storing the MMTP payload;
The data transmission system according to claim 1, further comprising: a transmission unit that repeatedly stores and transmits the MMTP payload stored in the payload storage unit in an MMTP packet. A receiving unit that receives the MMTP packet that stores the file that constitutes the content and the MMTP packet that stores the path name of each file that constitutes the content, which are repeatedly transmitted; and
A file restoring unit that restores a file having a desired path name from the MMTP packet received by the receiving unit with reference to the table;
The packet ID of MMTP packet storing the files that make up the content, Unlike packet ID of MMTP packet storing said table,
The receiving apparatus according to claim 1, wherein the table is a data directory management table . Computer
A receiving unit that receives the MMTP packet that stores the file that configures the content and the MMTP packet that stores the path name of each of the files that configure the content, which are repeatedly transmitted;
A program for referring to the table to function as a file restoration unit for restoring a file with a desired path name from an MMTP packet received by the reception unit,
The packet ID of MMTP packet storing the files that make up the content, Unlike packet ID of MMTP packet storing said table,
The program is a data directory management table .

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