JP7734008B2 - Sending device, receiving device and their programs, and transmission system - Google Patents

Description

The present invention relates to a transmitting device, a receiving device and associated programs, and a transmission system.

In December 2018, new 4K/8K satellite broadcasting in accordance with ARIB technical specifications STD-B60 and TR-B39 (see Non-Patent Documents 1 and 2) was launched as a digital broadcasting service in Japan.
The new 4K/8K satellite broadcasting uses MMT (MPEG Media Transport) as the international standard for a new media transport method based on IP (Internet Protocol).

"Media Transport Method Using MMT in Digital Broadcasting", ARIB STD-B60 "Advanced Wideband Satellite Digital Broadcasting Operational Standards (Volume 3)", ARIB-TR-B39 “Common media application format for segmented media”, ISO-IEC 23000-19

In a digital broadcasting system, a transmitter sends out a broadcast signal that complies with a specific transmission standard, and a dedicated receiver equipped with a demodulator (tuner) demodulates the received broadcast signal to make the content viewable. For example, the new 4K/8K satellite broadcasting system sends out broadcast signals that comply with ARIB STD-B60 and TR39.

Meanwhile, devices using platforms such as Android (registered trademark) and iOS are becoming increasingly popular as a means of viewing content. The streaming distribution standard CMAF (Common Media Application Format, see Non-Patent Document 3) is used to distribute content to these devices. Furthermore, many of these devices do not have demodulation devices capable of demodulating broadcast signals.

The present invention was devised in light of the above-mentioned circumstances, and aims to provide a transmission device, a receiving device and program therefor, and a transmission system that can make content transmitted by broadcast signals viewable in a transmission system in a manner compliant with CMAF.

In order to solve the above-mentioned problems, one aspect of the present invention is a transmission device that converts a group of files holding data for streaming distribution into a broadcast signal and transmits it, wherein the group of files holds timed data divided from an asset and includes a plurality of fragment files to which file names containing identification information for the timed data are assigned, the device comprising: a timed data generation unit that extracts the identification information from the file names of the fragment files and generates MMTP packets containing the timed data and the identification information of the fragment files; and a multiplexing unit that multiplexes the MMTP packets to generate the broadcast signal.

In order to solve the above-mentioned problems, one aspect of the present invention provides a receiving device that receives a broadcast signal generated from a group of files holding streaming distribution data and converts it into the group of files, wherein the group of files holds timed data divided from an asset and includes a plurality of fragment files to which file names containing identification information for the timed data are assigned, and the broadcast signal includes MMTP packets containing the timed data extracted from the fragment files and the identification information extracted from the file names of the fragment files, and includes a timed data conversion unit that extracts the timed data and the identification information from the MMTP packets, assigns file names containing the identification information to the timed data, and converts it into the fragment files.

As one aspect of the embodiment, the present invention can also be realized by a program for causing a computer to function as the above-described receiving device.
The present invention can also be realized in a transmission system including the above-described sending device and receiving device.

According to the present invention, content transmitted via broadcast signals can be viewed in a manner compliant with CMAF.

1 is a schematic configuration diagram of a broadcasting system according to an embodiment. FIG. 2 is a block diagram showing the configuration of the transmission device of FIG. 1; FIG. 2 is a block diagram showing the configuration of the receiving device of FIG. 1; FIG. 2 is a diagram illustrating the structure of a CMAF file group used in FIG. 1 . FIG. 2 is a diagram showing the structure of a broadcast signal used in FIG. 1; FIG. 2 is a diagram showing the structure of MMT-SI used in FIG. 1. FIG. 2 is a diagram illustrating the general structure of an MMTP packet used in FIG. 1. FIG. 2 is a diagram illustrating an example of a TD/MMTP packet used in FIG. 1 . FIG. 2 is a diagram illustrating an example of an NTD/MMTP packet used in FIG. 1 . FIG. 2 is a diagram illustrating an example of MMT-SI used in FIG. 1. 2 is a diagram showing the structure of a PA message that stores an MP table used in FIG. 1. 1. FIG. 4 is a diagram showing the structure of a data transmission message that stores a data directory management table used in FIG. A diagram showing the relationship between the tables included in the MMT-SI used in Figure 1 and the MPU. 10 is a flowchart illustrating an operation of the transmission device according to the embodiment. 4 is a flowchart illustrating an operation of the receiving device according to the embodiment. FIG. 2 is a hardware configuration diagram illustrating an example of a computer that realizes the functions of the receiving device according to the embodiment.

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below are intended to embody the technical concept of the present invention, and unless otherwise specified, the present invention is not limited to the following. Furthermore, in each embodiment, identical means will be designated by the same reference numerals, and their description may be omitted.

[Broadcasting system overview]
1, a broadcasting system 1, which is an example of a transmission system, includes a transmission device 2 and a reception device 3. The broadcasting system 1 performs digital broadcasting, and transmits a broadcast signal 200 conforming to ARIB STD-B60 and TR39 between the transmission device 2 and the reception device 3.

The transmission device 2 converts a group of files holding data for streaming distribution into a broadcast signal 200 and transmits the signal. A group of files (hereinafter referred to as "CMAF file group 100") conforming to CMAF, a standard for streaming distribution of content, is input to the transmission device 2 as a group of files holding data for streaming distribution. The CMAF file group 100 is made up of a plurality of files containing data that constitute the content.
The transmitting device 2 multiplexes the data included in the CMAF file group 100 onto a broadcast signal 200 and transmits it to the receiving device 3 via the broadcast network 5. The transmitting device 2 performs multiplexing in a manner that allows the receiving device 3 to convert the broadcast signal 200 into the CMAF file group 100.

The transmission device 2 multiplexes the CMAF file group 100 using a known multiplexing method, but in this embodiment, the multiplexing method is MMT. In other words, the transmission device 2 generates and multiplexes MMTP packets from the data contained in the CMAF file group 100 to generate the broadcast signal 200. The transmission device 2 can be configured, for example, from a computer installed in a broadcast station.

The receiving device 3 receives the broadcast signal 200 generated from a group of files holding streaming distribution data, and converts it into a group of files holding streaming distribution data.
The receiving device 3 receives the broadcast signal 200 from the transmitting device 2 via the broadcast network 5. The receiving device 3 converts the broadcast signal 200 into a CMAF file group 100 and deploys it on a distribution server. As an example, the receiving device 3 can be a computer built into a television receiving device installed in a home or the like.
1, the distribution server 36 of the receiving device 3 can be accessed by the presentation device 4 via the network 6. A URL is assigned to all data included in the CMAF file group 100. When the presentation device 4 accesses the URL, the file is distributed from the distribution server to the presentation device 4.

The presentation device 4 may be a terminal that employs a platform such as Android (registered trademark) or iOS and is capable of viewing content files to which CMAF is applied, such as a smartphone or tablet terminal. The presentation device 4 sends a request to the distribution server of the receiving device 3 and downloads the CMAF file group 100.
Although only one receiving device 3 and one presentation device 4 are shown in FIG. 1, a plurality of receiving devices 3 and a plurality of presentation devices 4 can be provided.

The configurations of the transmitting device 2 and the receiving device 3 will be described below.
[Sending device]
As shown in FIG. 2, the transmission device 2 includes an input unit 21 , an extraction unit 22 , a timed data generation unit 23 , a non-timed data generation unit 24 , a control message generation unit 25 , a multiplexing unit 26 , and a transmission unit 27 .
Although not shown in the figure, the transmission device 2 can be configured from a computer equipped with a CPU (Central Processing Unit), memory, input/output I/F (Interface), communication I/F, etc. The CPU executes a program stored in the memory, thereby realizing the functional configuration shown in Fig. 2.

(CMAF file group)
A group of CMAF files 100 constituting the content is input to the input unit 21 of the transmission device 2. The group of CMAF files 100 may be input to the transmission device 2 from another device (not shown) via a communication network or the like, or may be created by a computer constituting the transmission device 2.
As shown in FIG. 4, the CMAF file group 100 includes a fragment file 110, a manifest file 130, and an initialization file 150.

A fragment file 110 holds timed data separated from an asset and is given a filename that includes identification information for that timed data. An asset refers to a series of data, such as video and audio, that make up content. Timed data is data that has been separated (chunked) into units of several frames from an asset, and has a specified presentation time. CMAF aims to reduce latency in streaming delivery by transmitting chunked fragment files 110 using Chunked Transfer, an extension of HTTP.

A file name is assigned to each fragment file 110 that makes up the CMAF file group 100. The file name contains information (identification information) that can identify the fragment file 110. The file name contains, for example, an asset ID and a sequence number as identification information.
The asset ID is an identifier of the asset to which the fragment file 110 belongs, and the sequence number is a number that indicates the order of the fragment file 110 in the asset.

The manifest file 130 holds non-timed data, including rules for naming the fragment files 110. Non-timed data means data for which a presentation time is not specified. The manifest file 130 holds non-timed data, such as configuration information for the fragment files 110. The presentation device 4 (see FIG. 1 ) can play back content by continuously downloading the fragment files 110 in accordance with the manifest file 130.
As shown in FIG. 4, the manifest file 130 holds, as one piece of configuration information for the fragment files 110, file name rules 131 that define rules for file names given to the fragment files 110.

The initialization file 150 holds the metadata required to initialize the encoding process of the fragment file 110. The fragment file 110 and the initialization file 150 are also each given a file name.

(broadcast signal)
The transmitting device 2 converts the CMAF file group 100 shown in FIG.
5, the broadcast signal 200 is generated by multiplexing a sequence of MMTP packets. When the broadcast signal 200 is transmitted to the broadcast network 5, the sequence of MMTP packets is placed in the payload of an IP packet to be converted into an IP packet, and the IP packet is further placed in the payload of a TLV packet to be converted into a TLV packet, but illustration and detailed description thereof are omitted.

As shown in Figure 5, the broadcast signal 200 includes MMTP packets (hereinafter referred to as "TD/MMTP packets 210") containing timed data such as video and audio, and MMTP packets (hereinafter referred to as "NTD/MMTP packets 230") containing non-timed data such as applications. Furthermore, the MMTP packet sequence includes MMTP packets (hereinafter referred to as "MMT-SI 250") consisting of control information (signaling).

As shown in Figure 2, the transmission device 2 generates an MMTP packet sequence of the broadcast signal 200 shown in Figure 5 from a CMAF file group 100 (see Figure 4) through processing by an extraction unit 22, a timed data generation unit 23, a non-timed data generation unit 24, a control message generation unit 25, and a multiplexing unit 26.
The extraction unit 22 extracts the file naming rules for the fragment files 110 from the manifest file 130. The extraction unit 22 extracts the file naming rules 131 for the fragment files 110 from the manifest file 130 (see FIG. 4 ) of the CMAF file group 100 input to the input unit 21.

(File naming rules)
The manifest file 130 may be in XML format and conforms to the MPEG-DASH (Dynamic Adaptive Streaming over HTTP) specifications. In this case, as an example, the filename rule 131 for the fragment files 110 is written as follows:
{asset_id}{number}.{ext}
Here, {asset_id} is the asset ID, {number} is the sequence number, and {ext} is the extension that indicates the file type. In other words, filename rule 131 specifies that the file name should be expressed in the order of asset ID, sequence number, and extension. As mentioned above, fragment file 110 is a file that holds timed data obtained by dividing an asset. There may be multiple assets for each video and audio, in which case {asset_id} is unique for each asset.

For example, fragment files 110 split from a single asset that makes up video data are assigned the same asset ID. Fragment files 110 that belong to the same asset are then assigned consecutive sequence numbers according to the playback order. In other words, the combination of the asset ID and sequence number makes it possible to identify the asset to which the timed data held in a fragment file 110 belongs and its order within the asset.

An example of the file name rule 131 written in XML format in the manifest file 130 is shown below.
<SegmentTemplate media=”asset1_$Number$.m4s”>・・・・
...
</SegmentTemplate>
Here, the filename rule 131 is described as the media attribute of the SegmentTemplate property. "asset1_" corresponds to the asset ID ({asset_id}), "$Number$" corresponds to the sequence number ({number}), and ".m4s" corresponds to the extension ({ext}).

The timed data generation unit 23 extracts identification information from the file name of the fragment file 110, and generates an MMTP packet including the timed data and identification information of the fragment file 110. The timed data generation unit uses the file name rule 131 to extract the identification information (asset ID and sequence number) from the file name of the fragment file.
As shown in Figure 7, an MMTP packet is composed of an MMTP payload PL, which is the data body, and an MMTP header HD, which indicates information about the MMTP payload PL.
8, the timed data generation unit 23 generates a TD/MMTP packet 210 from the fragment file 110. The MMTP payload PL of the TD/MMTP packet 210 includes an MPU (Media Processing Unit) 211. The MPU 211 is composed of MPU metadata 212, movie fragment metadata 213, and an MFU (Media Fragment Unit) 214.

The timed data generation unit 23 extracts the timed data held in each fragment file 110 and stores it as an MFU 214. As shown below, the timed data generation unit 23 adds MPU metadata 212 and movie fragment metadata 213 to the MFU 214 to generate an MPU 211.

The timed data generating unit 23 refers to the filename rule 131 extracted by the extracting unit 22 and obtains the asset ID and sequence number (see FIG. 4) from the filename of the fragment file 110 .
8, the timed data generation unit 23 adds the extracted asset ID to the MPU metadata 212. The timed data generation unit 23 adds a sequence number as a movie fragment sequence number (movie_fragment_sequence_number) to the movie fragment metadata 213. Here, the movie fragment sequence number is a number that indicates the order within the asset of the MFU 214.

The timed data generator 23 further adds an MPU sequence number (mpu_sequence_number) to the MPU metadata 212. The MPU sequence number is a number that indicates the order of the MPUs 211 within the same asset.
The timed data generation unit 23 writes timed_flag=1 in the MMTP payload PL, which means that the data included in the MMTP payload PL is timed data.
The timed data generation unit 23 sequentially generates TD/MMTP packets 210 from a plurality of fragment files 110 belonging to each asset.

The non-timed data generation unit 24 generates an MMTP packet including the non-timed data held in the manifest file 130.
Specifically, the non-timed data generator 24 (see FIG. 2) generates the NTD/MMTP packet 230 (see FIG. 5) from the manifest file 130 and the initialization file 150 of the CMAF file group 100 .
Like the TD/MMTP packet 210, the NTD/MMTP packet 230 is composed of an MMTP payload PL, which is the data body, and an MMTP header HD, which indicates information about the MMTP payload PL (see Figure 7).
9 , the MMTP payload PL of the NTD/MMTP packet 230 includes an MPU 231. The MPU 231 is composed of MPU metadata 232 and an MFU 234.
The non-timed data generation unit 24 acquires data held in the manifest file 130, stores it as an MFU 234, and adds MPU metadata 232 to generate an MPU 231. Similarly, the non-timed data generation unit 24 acquires data held in the initialization file 150, stores it as an MFU 234, and adds MPU metadata 232 to generate an MPU 231.

The non-timed data generation unit 24 adds an item ID (item_id) for individually identifying the MPU 231 to the MPU metadata.
The non-timed data generation unit 24 writes timed_flag=0 in the MMTP payload PL. This means that the data included in the MMTP payload PL is non-timed data.

The control message generator 25 generates a control message that includes at least a portion of the identification information contained in the file name of the fragment file 110. Specifically, the control message generator 25 generates the control message MMT-SI 250 (see Figure 6) based on the TD/MMTP packet 210 and NTD/MMTP packet 230 generated by the timed data generator 23 and non-timed data generator 24. The generation of MMT-SI 250 can be performed in accordance with ARIB STD-B60 and TR39, so detailed explanations will be omitted below as appropriate.

As described above, MMT-SI 250 is an MMTP packet composed of control information (signaling). MMT-SI 250 is composed of an MMTP payload PL, which is the data body, and an MMTP header HD, which indicates information about the MMTP payload PL (see FIG. 6).
As shown in Figure 10, MMT-SI 250 consists of three layers: message MA, table TA, and descriptor DS. Message MA stores table TA and descriptor DS. Table TA has elements and attributes of timed data and non-timed data, and descriptor DS describes more detailed information.
As shown in FIG. 6, the MMT-SI 250 includes a PA message 251, a Data Transmission message 255, and the like as messages MA.
The PA message 251 stores, for example, an MP table 252 as a table TA.
A table related to data transmission is stored as table TA in the data transmission message 255. The data transmission message 255 stores, for example, a data directory management table 256, a data asset management table 257, and the like.

As shown in FIG. 11, a PA message 251 storing an MP table 252 is stored in the MMTP payload PL of an MMTP packet.
The MP table 252 indicates what components (assets) the content is made up of, and includes information such as a list of assets that make up the content (asset list), the location of the assets on the network (asset location), etc.

The control message generation unit 25 writes the asset ID in the MP table 252. The control message generation unit 25 further writes the MPU sequence number of the MPU 211 belonging to the asset in the MPU timestamp descriptor of the MP table 252. The MPU timestamp descriptor is the descriptor DS (see Figure 10) and is information indicating the presentation time of the MPU 211. By writing the asset ID that identifies the asset and the MPU sequence number that indicates the MPU 211 that belongs to the asset in the MP table 252, the receiving device 3 can read what assets and MPUs 211 the content is made up of.

As shown in FIG. 12, a data transfer message 255 storing a data directory management table 256 is stored in the MMTP payload of an MMTP packet.
The data directory management table 256 is a table that describes the directory structure of the files that make up an application.
The control message generator 25 writes the file names (file_name) of the manifest file 130 and the initialization file 150 that have been converted into NTD/MMTP packets 230 by the non-timed data generator 24 into the data directory management table 256 .

13, the data asset management table 257 is a table that describes the configuration of the MPUs 211 in the asset and information about each MPU 211. Although not shown, the data asset management table 257, like the data directory management table 256, is also stored in the data transmission message 255 of the MMTP payload.
As shown in Figure 13, the data asset management table 257 contains information for linking other tables (data directory management table 256, MP table 252) with the MPU 231 of the TD/MMTP packet 210 and the NTD/MMTP packet 230.

For example, an item ID is written in the data asset management table 257. As described above, the item ID is an identifier of the MPU 231 of the NTD/MMTP packet 230, and is also written in the MPU metadata 232 of the NTD/MMTP packet 230.
The data asset management table 257 also includes a node tag (Node_tag) as information for linking with the data directory management table 256. The node tag indicates a label that identifies a directory or file as the node tag of the directory or file.

The data asset management table 257 also contains a component tag (component_tag) as information for linking with the MP table 252. The component tag indicates a label for identifying the component (asset).

The multiplexing unit 26 multiplexes the MMTP packets generated by the timed data generating unit to generate the broadcast signal 200. The multiplexing unit 26 further multiplexes the control messages generated by the control message generating unit 25 to generate the broadcast signal 200. The multiplexing unit 26 further multiplexes the MMTP packets generated by the non-timed data generating unit 24 to generate the broadcast signal 200.
The multiplexing unit 26 multiplexes the TD/MMTP packet 210, the NTD/MMTP packet 230, and the MMT-SI 250 to generate an MMTP packet sequence (see FIG. 5). The multiplexing unit 26 packetizes the MMTP packet sequence into an IP packet by placing it on the payload of the IP packet.

The sending unit 27 loads the IP packet into the payload of a TLV packet to convert it into a TLV packet, and sends it to the broadcast network 5 as a broadcast signal 200, as shown in Figure 1.

[Receiving device]
As shown in FIG. 3, the receiving device 3 includes a receiving unit 31, a packet filter 32, a non-timed data conversion unit 33, an extraction unit , a timed data conversion unit 35, and a distribution server .
The receiving unit 31 receives the broadcast signal 200 transmitted from the transmitting device 2 via the broadcast network 5 .

The packet filter 32 separates the MMTP packet sequence carried on the broadcast signal 200 and extracts the TD/MMTP packet 210, the NTD/MMTP packet 230, and the MMT-SI 250.

The non-timed data conversion unit 33 converts the MMTP packets containing non-timed data into a manifest file 130 .
Specifically, non-timed data conversion unit 33 converts NTD/MMTP packets 230 extracted by packet filter 32 into manifest file 130 and initialization file 150 that make up CMAF file group 100 .
The non-timed data conversion unit 33 extracts data stored as MFU 234 in the MMTP payload PL of the NTD/MMTP packet 230 and converts it into a file. The non-timed data conversion unit 33 obtains a file name (file_name) corresponding to the filed data from the data directory management table 256 (see FIG. 12 ) and assigns the file name to the created file. As shown in FIG. 13 , the data directory management table 256, which lists file names, and the data asset management table 257, which lists item IDs (item_id) that identify the MPU 231 of the NTD/MMTP packet 230, are linked by a node tag (Node_tag). The non-timed data conversion unit 33 can assign file names by referencing the node tag and item ID.
As described above, in transmission device 2, the file names of manifest file 130 and initialization file 150 are assigned as file names (file_name) of the NTD/MMTP packets 230. Therefore, by processing by non-timed data conversion unit 33, it is possible to restore manifest file 130 and initialization file 150 input to transmission device 2 from NTD/MMTP packets 230.

As described above, the manifest file 130 holds filename rules 131 that define the filenames to be given to the fragment files 110 (see FIG. 4).
The extraction unit 34 (filename rule extraction unit) extracts the filename rule 131 from the manifest file 130 .
As shown in FIG. 3, the extraction unit 34 extracts the file name rule 131 from the manifest file 130 converted by the non-timed data conversion unit 33 .

The timed data conversion unit 35 extracts timed data and identification information from an MMTP packet containing timed data extracted from the fragment file 110 and identification information extracted from the file name of the fragment file 110, and converts the timed data into a fragment file 110 by assigning a file name containing the identification information to the timed data.
The timed data conversion unit 35 converts the TD/MMTP packets 210 extracted by the packet filter 32 into fragment files 110 that make up the CMAF file group 100. The timed data conversion unit 35 refers to the asset ID and MPU sequence number in the MP table 252, and sequentially processes the MPUs 211 that belong to each asset that makes up the content.

The timed data conversion unit 35 extracts the timed data stored as the MFU 214 (see FIG. 8) in the MMTP payload of the TD/MMTP packet 210 and converts it into a file.
As described above, the fragment files 110 that make up the CMAF file group 100 are given file names that include an asset ID and a sequence number (see FIG. 4). The timed data conversion unit 35 references the file naming rules 131 extracted by the extraction unit 34, acquires the asset ID from the MPU metadata 212, and acquires the sequence number from the movie fragment metadata 213. The timed data conversion unit 35 assigns a file name that includes the asset ID and a sequence number to the created file in accordance with the file naming rules 131.

The timed data conversion unit 35 sequentially processes the MPU 211 included in the TD/MMTP packet 210, thereby restoring the fragment files 110 that make up the CMAF file group 100.
Non-timed data conversion unit 33 and timed data conversion unit 35 store the created manifest file 130, initialization file 150, and fragment file 110 in distribution server 36. Distribution server 36 distributes these files to presentation device 4 (see FIG. 1 ) in response to a request from presentation device 4.

[Operation of the sending device]
The sending device 2 can start processing when the CMAF file group 100 is input to the input unit 21. Note that input of all files constituting the CMAF file group 100 does not have to be completed; for example, processing may start when the manifest file 130 and the initialization file 150 are input.
As shown in FIG. 14, the extraction unit 22 extracts the filename rule 131 of the fragment file 110 from the manifest file 130 of the input CMAF file group 100 (step S01).

The timed data generation unit 23 generates a TD/MMTP from the fragment file 110 (step S02). In doing so, the timed data generation unit 23 references the filename rules 131 to extract the asset ID and sequence number from the filename of the fragment file 110, adds the asset ID to the MPU metadata 212, and adds the sequence number as a movie fragment sequence number to the movie fragment metadata 213.

Non-timed data generator 24 generates NTD/MMTP from manifest file 130 and initialization file 150 (step S03).
The control message generator 25 generates the MMT-SI 250 (step S04). At this time, the control message generator 25 adds an asset ID to the MP table 252, and adds the file names of the manifest file 130 and the initialization file 150 to the data directory management table 256.
The multiplexing unit 26 multiplexes the TD/MMTP, NTD/MMTP, and MMT-ST to generate the broadcast signal 200 (step S05). The sending unit 27 sends the broadcast signal 200 to the receiving device 3 via the broadcast network 5 (step S06).

[Operation of receiving device]
As shown in FIG. 15, when the receiving device 3 receives the broadcast signal 200, the packet filter 32 separates the broadcast signal 200 (step S11).
The non-timed data conversion unit 33 converts the NTD/MMTP packet 230 into the manifest file 130 and the initialization file 150 (step S12).
The extraction unit 34 extracts the filename rule 131 of the fragment file 110 from the manifest file 130 (step S13).

The timed data conversion unit 35 converts the TD/MMTP packet 210 into the fragment file 110 (step S14). At this time, the timed data conversion unit 35 refers to the filename rule 131, extracts the asset ID from the MPU metadata 212, and extracts the movie fragment sequence number from the movie fragment metadata 213. The timed data conversion unit 35 assigns a filename including the asset ID and the sequence number to the fragment file 110 in accordance with the filename rule 131.
The non-timed data conversion unit 33 and the timed data conversion unit 35 store the created CMAF file group 100 in the distribution server 36 (step S15).

[Hardware configuration]
The computer 900 includes a CPU 901 , a memory 902 , an input/output I/F 903 , a communication I/F 904 , and a media I/F 905 .

The CPU 901 of the computer 900 executes a program loaded onto the memory 902 to realize the functions of the receiving device 3. Alternatively, the CPU 901 may load a program related to the target processing from another device via a network.
The CPU 901 receives input from an input device 910 via an input/output I/F 903. The input device 910 may be, for example, a mouse or a keyboard, or, if the receiving device 3 is a television receiving device, a remote controller. The CPU 901 controls output devices such as a display and a distribution server 36 via the input/output I/F 903.

The communication I/F 904 receives data from other devices such as the transmission device 2 (see FIG. 1) via the broadcast network 5 and outputs the data to the CPU 901 .
The media I/F 905 reads a program or data stored in the recording medium 912 and outputs it to the CPU 901 via the memory 902. The CPU 901 loads a program related to a target process from the recording medium 912 onto the memory 902 via the media I/F 905, and executes the loaded program. The recording medium 912 can be an optical recording medium such as a CD-ROM or DVD, a magnetic recording medium, a magneto-optical recording medium, a semiconductor memory, or the like.

[Actions and Effects]
As described above, the sending device 2 and the receiving device 3 in the broadcasting system 1 according to the embodiment have the following configurations.
(1) The transmitting device 2 converts a CMAF file group 100, which is a file group that holds data for streaming distribution, into a broadcast signal 200 and transmits it.
The CMAF file group 100 holds timed data divided from an asset, and includes a plurality of fragment files 110 given file names that include identification information of the timed data.
The sending device 2 includes:
a timed data generation unit (23) that extracts identification information from the file name of the fragment file (110) and generates a TD/MMTP packet (210) that is an MMTP packet including the timed data and identification information of the fragment file (110);
and a multiplexing unit 26 that multiplexes the TD/MMTP packets 210 to generate a broadcast signal 200.

When the sending device 2 generates the TD/MMTP packet 210 from the fragment file 110, the identification information assigned to the file name is included, allowing the receiving device 3 to obtain the identification information of the fragment file 110 along with the timed data held in the fragment file 110. The receiving device 3 assigns a file name including the identification information of the fragment file 110 to the acquired timed data and files it, allowing the fragment file 110 to be easily restored from the TD/MMTP packet 210.

(2) The CMAF file group 100 includes a manifest file 130 that holds non-timed data including a file name rule 131 that is a rule for the file names given to the fragment files 110 .
The sending device 2 includes an extracting unit 22 that extracts the filename rule 131 from the manifest file 130 .
The timed data generating unit 23 extracts the identification information from the file name of the fragment file 110 using the file name rules.

By the extraction unit 22 extracting the file name rules 131 recorded in the manifest file 130, the timed data generation unit 23 can easily extract identification information from the fragment file 110 by referring to the file name rules 131.

(3) The identification information includes an identifier of the asset to which the timed data held in the fragment file 110 belongs, and a sequence number indicating the order of the timed data in the asset.
Since the identification information includes an asset ID and a sequence number, it is possible to easily identify the timed data held in the fragment file 110 from the file name of the fragment file 110 .

(4) The transmission device 2 includes a control message generator 25 that generates an MMT-SI 250 (control message) that includes an asset ID (at least a part of the identification information).
The multiplexing unit 26 further multiplexes the MMT-SI 250 to generate the broadcast signal 200 .

The PA table of the MMT-SI 250 includes an asset ID, which is part of the identification information, and an MPU sequence number that identifies the MPU 211 that constitutes the TD/MMTP packet 210. This allows the receiving device 3 to sequentially convert fragment files 110 from the TD/MMTP packet 210 by referring to the PA table.

(5) The transmission device 2 includes a non-timed data generation unit 24 that generates an NTD/MMTP packet 230, which is an MMTP packet including non-timed data held in the manifest file 130.
The multiplexing unit 26 further multiplexes the NTD/MMTP packets 230 to generate the broadcast signal 200 .

By transmitting the manifest file 130 in addition to the fragment file 110 as MMTP packets in the transmission device 2, the receiving device 3 can also extract the filename rule 131 from the manifest file 130 and assign filenames to the fragment files 110 in accordance with the filename rule 131. This allows the CMAF file group 100 input to the transmission device 2 from the broadcast signal 200 to be restored.

(6) The receiving device 3 receives the broadcast signal 200 generated from the CMAF file group 100 that holds the streaming distribution data, and converts it into the CMAF file group 100.
The CMAF file group 100 holds timed data divided from an asset, and includes a plurality of fragment files 110 given file names that include identification information of the timed data.
The broadcast signal 200 includes a TD/MMTP packet 210 containing timed data extracted from the fragment file 110 and identification information extracted from the file name of the fragment file 110 .
The receiving device 3 is equipped with a timed data conversion unit 35 that extracts timed data and identification information from the TD/MMTP packet 210, assigns a file name including the identification information to the timed data, and converts it into a fragment file 110.

As described above, the sending device 2 generates the TD/MMTP packet 210 including the identification information assigned to the file name of the fragment file 110, so the receiving device 3 can obtain the identification information of the fragment file 110 from the TD/MMTP packet 210 along with the timed data held by the fragment file 110. Furthermore, by assigning a file name including the identification information to the timed data acquired by the receiving device 3 and filing it, the fragment file 110 can be easily restored from the MMTP packet.

(7) The CMAF file group 100 includes a manifest file 130 that holds non-timed data including a filename rule 131 for fragment files.
The broadcast signal 200 is generated by multiplexing TD/MMTP packets 210 containing timed data as well as NTD/MMTP packets 230 containing non-timed data.
The receiving device 3
a non-timed data conversion unit that converts a TD/MMTP packet including non-timed data into a manifest file;
The manifest file 130 includes an extraction unit 34 (filename rule extraction unit) that extracts the filename rule 131 of the fragment file 110 from the manifest file 130.
The timed data conversion unit 35 extracts the identification information from the TD/MMTP packet 210 using the file name rule 131 .

By transmitting the manifest file 130 as an MMTP packet in the sending device 2, the receiving device 3 can extract the filename rule 131 of the fragment file 110 from the manifest file 130 and assign the filename of the fragment file 110 to the timed data extracted from the TD/MMTP packet 210 in accordance with the filename rule 131. This makes it possible to restore the CMAF file group 100 input to the sending device 2.

(8) The same effect can be achieved with a program for causing the computer 900 to function as the receiving device 3 described above.
(9) The same effect can be achieved with the broadcasting system 1 (transmission system) that includes the above-described sending device 2 and receiving device 3.

In the above-described embodiment, an example was described in which the sending device 2 starts the processing shown in FIG. 14 when the manifest file 130 and initialization file 150 of the CMAF file group 100 are input, but this is not limited to this. For example, a data carousel function that performs processing periodically may be added to the sending device 2, so that the processing shown in FIG. 14 is performed periodically. This allows a receiving device 3 that is started at any timing to receive all MMTP packets converted from the CMAF file group 100.

The present invention can also be applied to a multicast ABR system, which transmits ABR (adaptive bit rate) files such as HLS and MPEG-DASH by multicast, and whose introduction is being considered in the CATV industry.
When a multicast ABR system is based on A176 (DVB BlueBook A176, published in March 2020) established by DVB (Digital Video Broadcasting), an open standard for digital television broadcasting, the receiving device 3 in the embodiment can be replaced with a content distribution device (content hosting) defined in A176. The content distribution device is a device that accumulates fragment files 110 and transmits them to a multicast server by unicast.
By inputting the broadcast signal 200 from the sending device 2 to the content distribution device, the present invention can be applied to a multicast ABR system implemented based on A176.

In the above-described embodiment, a broadcasting system 1 that transmits broadcast signals between a sending device 2 and a receiving device 3 via a broadcasting network 5 was described as an example of a transmission system, but the present invention is not limited to this. The present invention can also be applied to a transmission system that transmits broadcast signals between a sending device 2 and a receiving device 3 via another transmission path, such as a communication network (IP network).

REFERENCE SIGNS LIST 1 Broadcasting system 2 Sending device 3 Receiving device 21 Input unit 22 Extraction unit 23 Timed data generating unit 24 Non-timed data generating unit 25 Control message generating unit 26 Multiplexing unit 27 Sending unit 31 Receiving unit 32 Packet filter 33 Non-timed data converting unit 34 Extraction unit 35 Timed data converting unit 36 Distribution server

Claims (9)

A transmission device that converts a group of files holding streaming distribution data into broadcast signals and transmits the signals,
the file group includes a plurality of fragment files each holding timed data divided from an asset and each having a file name including identification information of the timed data;
a timed data generation unit that extracts the identification information from the file name of the fragment file and generates an MMTP packet including the timed data of the fragment file and the identification information;
A transmission device characterized by comprising: a multiplexing unit that multiplexes the MMTP packets to generate the broadcast signal. the group of files includes a manifest file that holds non-timed data including rules for naming the fragment files;
an extracting unit that extracts the file name rule from the manifest file;
2. The transmission device according to claim 1, wherein the timed data generation unit extracts the identification information from the file names of the fragment files using the file name rules. The transmission device described in claim 2, characterized in that the identification information includes an identifier of the asset to which the timed data stored in the fragment file belongs and a sequence number indicating the order of the timed data in that asset. a control message generating unit that generates a control message including at least a part of the identification information;
4. The transmission device according to claim 2, wherein the multiplexing unit further multiplexes the control messages to generate the broadcast signal. a non-timed data generation unit that generates an MMTP packet including the non-timed data held in the manifest file;
The transmission device according to claim 4, wherein the multiplexing unit further multiplexes the MMTP packets generated by the non-timed data generating unit to generate the broadcast signal. A receiving device that receives a broadcast signal generated from a group of files holding streaming distribution data and converts the signal into the group of files,
the file group includes a plurality of fragment files each holding timed data divided from an asset and each having a file name including identification information of the timed data;
the broadcast signal includes an MMTP packet including the timed data extracted from the fragment file and the identification information extracted from the file name of the fragment file;
A receiving device characterized by comprising a timed data conversion unit that extracts the timed data and the identification information from the MMTP packet, and converts the timed data into the fragment file by assigning a file name including the identification information to the timed data. the group of files includes a manifest file that holds non-timed data including rules for naming the fragment files;
the broadcast signal is generated by multiplexing an MMTP packet including the non-timed data in addition to an MMTP packet including the timed data,
a non-timed data conversion unit that converts an MMTP packet including the non-timed data into the manifest file;
a filename rule extraction unit that extracts the filename rule from the manifest file,
The receiving device according to claim 6, wherein the timed data conversion unit extracts the identification information from an MMTP packet including the timed data using the file name rule. Computer,
A program for causing the receiving device according to claim 6 or 7 to function. A transmission system comprising: a sending device that converts a group of files holding streaming distribution data into a broadcast signal and sends it; and a receiving device that receives the broadcast signal and converts it into the group of files,
the file group includes a plurality of fragment files each holding timed data divided from an asset and each having a file name including identification information of the timed data;
The delivery device includes:
a timed data generation unit that extracts the identification information from the file name of the fragment file and generates an MMTP packet including the timed data of the fragment file and the identification information;
a multiplexing unit that multiplexes the MMTP packets to generate the broadcast signal,
The receiving device
A transmission system characterized by comprising a timed data conversion unit that extracts the timed data and the identification information from the MMTP packet, and converts the timed data into the fragment file by assigning a file name including the identification information to the timed data.