JP4886765B2 - File transmission device and file reception device - Google Patents

Description

  The present invention relates to a file transmission device and a file reception device in a download system for copying and including metadata necessary for content reproduction in a file and transmitting the file via a unidirectional communication line that is digital broadcasting or multicast communication. About.

Conventionally, various techniques for downloading contents such as software, video, music, etc. via a bidirectional communication line such as an IP network have been proposed (see, for example, Patent Document 1).
In recent years, with the expansion of digital broadcasting and the like, content download services are expected through unidirectional communication lines such as BS digital broadcasting and mobile broadcasting.
JP 2007-212234 A

  Normally, it is assumed that a data error or data loss occurs on a transmission line in a two-way communication line, and even if these occur, a method for retransmitting data has been established, and the user cannot complete content. Can be downloaded in any form.

  However, in a unidirectional communication line such as a broadcast wave, it is not assumed that data with a data error or data loss is retransmitted, and the content is provided to the user while the data error or data loss is included. There is a possibility that. For example, when a download service is provided by BS digital broadcasting, a data error or data loss occurs in a large number of receiving apparatuses installed over a wide range due to rain attenuation. Also, when providing a download service via mobile broadcasting, mobile reception is mainly used. Therefore, depending on the lifestyle of the user, the reception situation, that is, the situation in which data error or data loss occurs differs. Become.

  For example, the content to be downloaded is encoded in various file formats such as a multipart format including MPEG (Moving Picture Experts Group) -2 TS (Transport Stream), an MP file format, a 3GPP format, or a 3GPP2 format. Therefore, the content to be downloaded includes not only media data such as music data and video data, but also metadata storing the file format and the copyright information of the content. In the conventional download service, as shown in FIG. 6, it is common to provide a user with a file in which media data and metadata are multiplexed.

  Here, even if a data error or data loss occurs in the media data, if the video and audio are allowed to be disturbed, the receiving device can reproduce the media data, and the download service can be maintained. On the other hand, if a data error or data loss occurs in the metadata, the metadata cannot be used, the content title cannot be displayed, or the license required for playing the content cannot be obtained, and the download service It cannot be maintained. That is, in the download service, there are data that can tolerate data errors and data loss and data that cannot tolerate data errors and data loss.

  Therefore, an object of the present invention is to provide a file transmission device and a file reception device that can easily maintain a download service even if a data error or data loss occurs in a unidirectional communication line.

  In order to solve the above-described problem, a file transmission apparatus according to claim 1 is a file transmission apparatus that transmits a file including media data serving as content contents via a unidirectional communication line that is digital broadcasting or multicast communication. A file transmission apparatus in a download system comprising one or more file reception apparatuses for receiving a file, comprising: division control information generation means, media data division means, metadata duplication means, multiplexing means, and file transmission And means.

  According to this configuration, the file transmission apparatus calculates the number of divisions for dividing the media data into a preset size by the division control information generation unit, and generates division control information including the number of divisions. In addition, the file transmission apparatus generates media data by dividing the media data into the number of divisions based on the division control information generated by the division control information generation unit when the media data is input by the media data division unit.

  In addition, the file transmission device receives metadata necessary for reproducing the media data by the metadata copying unit, adds the division control information to the metadata, and duplicates the metadata to which the division control information is added. The same number of duplicate metadata as the number of divisions is generated. Then, the file transmission device generates a file by multiplexing so that the metadata is the head, the duplicate metadata is arranged in front of the divided media data, and the duplicate metadata is multiplexed at regular intervals. Further, the file transmission device transmits the file generated by the multiplexing unit to the file reception device by the file transmission unit.

  Here, for example, the media data has a large size from 1 Mbytes to 9 Gbytes, while the metadata has a small size of 100 Kbytes or less. In consideration of this property, the file transmission device generates a file in which each piece of duplicate metadata is included between the divided media data at regular intervals, and transmits the file to the file reception device. As a result, the file transmission apparatus can reduce the occurrence of data errors and data loss in the metadata and all the duplicate metadata as much as possible.

  The file transmission device according to claim 2 is the file transmission device according to claim 1, wherein the metadata duplicating unit adds the position of the duplicate metadata in the file to the division control information added to the metadata and the duplicate metadata. The positional information to show is included.

  According to such a configuration, the file transmission device causes the file reception device to quickly read the duplicate metadata included in the file based on the position information indicating the position of the duplicate data in the file.

  In order to solve the above-described problem, the file receiving apparatus according to claim 3 transmits a file including media data as content contents via a unidirectional communication line that is digital broadcasting or multicast communication. A file receiving apparatus in a download system comprising an apparatus and one or more file receiving apparatuses for receiving a file, the file receiving means, the file storage means, the metadata loss determining means, the metadata repairing means, and the media And a data reproducing means.

  According to such a configuration, the file receiving device uses the file receiving unit to start with the metadata necessary for reproduction of the media data, and copy the metadata that is duplicated before the divided media data obtained by dividing the media data. A file in which data is arranged and multiplexed so that duplicate metadata is at regular intervals is received. Further, the file receiving device stores the file received by the file receiving unit by the file storing unit. Then, the file receiving apparatus determines whether the metadata included in the file stored by the file storage unit is missing by the metadata loss determination unit.

  In addition, the file receiving device reads the duplicate metadata included in the file accumulated by the file storage means when the metadata restoration means determines that the metadata is missing, and the duplicate metadata is missing. And the metadata included in the file stored by the file storage means is overwritten with the duplicated metadata determined not to be missing. Further, the file receiving apparatus refers to the metadata by the media data reproducing means and reproduces the divided media data.

  Here, for example, the media data has a large size from 1 Mbytes to 9 Gbytes, while the metadata has a small size of 100 Kbytes or less. The file receiving apparatus receives a file generated in consideration of this property and including a plurality of duplicate metadata at regular intervals between divided media data. Thus, the file receiving apparatus can reproduce the media data as long as no data error or data loss occurs in the metadata and all the duplicate metadata.

  The file reception device according to claim 4 is the file reception device according to claim 3, wherein the file reception means indicates the position of the duplicate metadata in the file in the metadata and the duplicate metadata included in the received file. Division control information including information is added, and the metadata restoration unit reads the duplicate metadata included in the file accumulated by the file accumulation unit based on the position information included in the division control information. .

  According to such a configuration, it is possible to quickly read out the duplicate metadata included in the file stored in the file storage unit with reference to the position information indicating the position of the replicated data in the file in the file receiving apparatus.

According to the present invention, the following excellent effects can be obtained.
According to the first aspect of the invention, the file transmission device can reduce the occurrence of data errors and data loss in the metadata and all the duplicate metadata as much as possible, so that the file reception device cannot reproduce the media data. Even if a data error or data loss occurs in the unidirectional communication line, the download service can be easily maintained.

  According to the second aspect of the present invention, the file transmission apparatus causes the file reception apparatus to quickly read the duplicate metadata included in the file based on the position information indicating the position of the duplicate data in the file. The speed of metadata repair processing by the device is improved.

  According to the invention of claim 3, since the file receiving device can reproduce the media data as long as no data error or data loss occurs in the metadata and all the duplicate metadata, the data receiving device Even if data loss occurs, the download service can be easily maintained.

  According to the invention of claim 4, the file receiving device refers to the position information indicating the position of the duplicate data in the file and quickly reads the duplicate metadata included in the file accumulated in the file accumulation means. The speed of the repair process is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each embodiment, means having the same function and the same member are denoted by the same reference numerals, and description thereof is omitted.

[Configuration of file sending device]
With reference to FIG. 1, the structure of the file transmission apparatus which concerns on this embodiment of this invention is demonstrated. FIG. 1 is a block diagram showing the configuration of a file transmission apparatus according to this embodiment of the present invention. As shown in FIG. 1, the file transmission apparatus 1 transmits a file including media data serving as contents via a unidirectional communication line M, and includes fragment information generation means (division control information generation means). 11, a fragmenting means (media data dividing means) 13, a metadata copying means 15, a containerizing means (multiplexing means) 17, and a file transmitting means 19.

  The fragment information generation means (division control information generation means) 11 calculates the number of divisions for dividing the media data into a preset size and generates fragment information (division control information) including this division number. In the present embodiment, for example, when the media data is 3 Gbytes and the size is set to 1 Gbyte, the fragment information generation unit 11 calculates the division number as “3”. For example, when the media data is 3 Gbytes and the size is set to 1 Gbyte, the fragment information generation unit 11 calculates the division number as “3”.

  Fragmenting means (media data dividing means) 13 receives media data, and generates divided media data by dividing the media data into the number of divisions based on the fragment information generated by fragment information generating means 11. . In this embodiment, for example, when the media data is 3 Gbytes and the number of divisions is “3”, the fragmentation unit 13 generates three pieces of divided media data having a size of 1 Gbyte. In addition, for example, when the media data is 2.5 Gbytes and the number of divisions is “3”, the fragmentation means 13 generates two pieces of divided media data having a size of 1 Gbyte and a size of 0.5 Gbytes. Generate one piece of divided media data

  The fragmentation means 13 adds a fragment ID for uniquely identifying each divided media data to the head of each generated divided media data. Then, the fragmentation means 13 outputs all the divided media data to which the fragment ID is added to the containerization means 17. The fragmentation means 13 corresponds to the media data dividing means described in the claims.

  The metadata duplicating unit 15 receives metadata and adds fragment information to the metadata. Then, the metadata duplicating unit 15 duplicates the metadata to which the fragment information is added, generates duplicated metadata having the same number as the division number, and outputs the metadata and all duplicated metadata to the containerizing unit 17. In the present embodiment, the metadata copying unit 15 includes position information indicating the position of the duplicate metadata in the file in the metadata and the fragment information added to the duplicate metadata. That is, the fragment information of the metadata and the duplicate metadata includes the number of divisions, the size of the divided media data, and the position information.

  The containerization means (multiplexing means) 17 starts with the metadata output by the metadata copying means 15 and uses the duplicate metadata output by the metadata copying means 15 before the divided media data generated by the fragmentation means 11. The files are arranged and containerized (multiplexed) so that the duplicate metadata is at a constant interval. In the present embodiment, the containerization means 17 containerizes in the format of “ISO / IEC 14496-12 ISO based media file format” including metadata, duplicate metadata, fragment ID, and divided media data. To do. The file data structure will be described later.

  The file transmission means 19 transmits the file generated by the containerization means 17 to the file reception device 2 (see FIG. 4). In this embodiment, the file transmission means 19 transmits a file by the “ISO / IEC 13818-6 DSM-CC data carousel system” via the unidirectional communication line M which is digital broadcasting such as BS digital broadcasting and mobile broadcasting. . In the present invention, as the unidirectional communication line M, IP multicast communication (IP multicast broadcast), which is a unidirectional communication method similar to digital broadcasting, can be used.

  The file transmitting apparatus 1 can be configured by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an HDD (Hard Disk Drive). Further, the file transmission device 1 may include an antenna (not shown) for transmitting BS digital broadcast or mobile broadcast.

<File data structure>
Hereinafter, the data structure of the file in the present invention will be described with reference to FIG. 2 (see FIG. 1 as appropriate). FIG. 2 is a diagram showing a data structure of a file in the present invention, (a) is a diagram showing a data structure of the entire file, and (b) is a diagram showing a data structure of metadata included in the file. It is. FIG. 2A shows an example in which media data is divided into three (number of divisions = 3).

  Specifically, the file includes a fragment ID indicating the first divided media data, the first duplicate metadata 1, the first divided media data 1, Are stored in order. Subsequently, the fragment ID indicating the second divided media data, the second duplicate metadata 2, and the second divided media data 2 are sequentially stored in the file. Further, the fragment ID indicating the third divided media data, the third duplicate metadata 3, and the third divided media data 3 are sequentially stored in the file. That is, duplicate metadata is arranged in the file at regular intervals.

The metadata is necessary for reproducing the media data, and has a metadata part and a fragment information part as shown in FIG. The metadata part is metadata input to the metadata copying unit 15. For example, the metadata part includes content type (format) information, content ID for uniquely identifying the content, content capacity, content title information, and content copyright information.
The fragment information part is fragment information added to the metadata by the metadata copying unit 15. For example, the fragment information portion includes the number of divisions, the size of divided media data, and position information.

Returning to FIG. 2A, the description will be continued.
The fragment IDs 1 to 3 uniquely identify the divided media data 1 to 3. The fragment IDs 1 to 3 are used for special reproduction described later.
The duplicate metadata 1 to 3 are duplicates of the metadata and have the same data structure as the metadata shown in FIG.
The divided media data 1 to 3 are obtained by dividing the media data by the number of divisions described above.

[Operation of file sending device]
With reference to FIG. 3, the operation of the file transmission apparatus of FIG. 1 will be described (see FIG. 1 as appropriate). FIG. 3 is a flowchart showing the operation of the file transmission apparatus of FIG.

  First, the file transmission device 1 calculates the number of divisions for dividing the media data into a preset size by the fragment information generation unit 11 and generates fragment information including the number of divisions (step S11: fragment information generation step). .

  Subsequent to the processing of step S11, the file transmission apparatus 1 divides the media data into the number of divisions based on the fragment information generated by the fragment information generation unit 11 when the media data is input by the fragmentation unit 13. Media data is generated (step S12: fragmentation step).

  Subsequent to the processing in step S12, the file transmitting apparatus 1 receives the metadata by the metadata duplicating unit 15, adds the fragment information to the metadata, and duplicates the metadata to which the fragment information is added. And the same number of duplicate metadata are generated (step S13: metadata duplication step)

  Subsequent to the processing in step S13, the file transmitting apparatus 1 causes the containerizing unit 17 to set the metadata output from the metadata copying unit 15 as the head and copy the metadata before the divided media data generated by the fragmenting unit 11. The duplicate metadata output by the means 15 is arranged and containerized so that the duplicate metadata is at a constant interval to generate a file (step S14: containerization step). Then, the file transmission device 1 transmits the file generated by the containerization unit 17 to the file reception device by the file transmission unit 19 (step S15: file transmission step).

[Configuration of file receiver]
With reference to FIG. 4, the structure of the file receiver which concerns on this embodiment of this invention is demonstrated. FIG. 4 is a block diagram showing the configuration of the file receiving apparatus according to this embodiment of the present invention. As shown in FIG. 4, the file receiving device 2 receives a file via a unidirectional communication line M, and includes a file receiving unit 21, a file storage unit 22, a metadata check unit (metadata missing) Determination means) 23, metadata restoration means 24, and media data reproduction means 25.

  The file receiving means 21 is a file in which the metadata is multiplexed via the unidirectional communication line M, the duplicate metadata is arranged in front of the divided media data, and the duplicate metadata is at regular intervals. Is to be received. In the present embodiment, the file receiving means 21 receives a file having a data structure as shown in FIG.

  The file storage unit 22 stores the file received by the file reception unit 21 and is, for example, an HDD (Hard Disk Drive) or a RAM (Random Access Memory). Here, for example, when the metadata of the received file is missing due to rain attenuation, the metadata is accumulated in the file accumulating unit 22 in a state where the metadata is missing.

  The metadata check means (metadata check loss determination means) 23 determines whether or not the metadata included in the file stored by the file storage means 22 is missing. In the present embodiment, the metadata check unit 23 reads the metadata included in the file stored by the file storage unit 22 when the file is stored in the file storage unit 22, and the metadata check unit 23 reads the metadata when the metadata cannot be read. It is determined that the data is missing, and if the metadata can be read, it is determined that the metadata is not missing. Note that the timing at which the metadata check unit 23 checks the metadata is not limited to when the file is stored in the file storage unit 22. For example, the metadata check unit 23 may check the metadata every time media data is reproduced.

  If the metadata check unit 23 determines that the metadata is missing, the metadata check unit 23 outputs an overwrite command for overwriting the metadata with the duplicate metadata to the metadata overwriting unit 24a described later. On the other hand, when it is determined that the metadata is not missing, the metadata check unit 23 outputs a metadata read command to the metadata read unit 24b described later. The metadata check unit 23 corresponds to the metadata check defect determination unit described in the claims.

In this embodiment, the metadata restoration unit 24 includes a metadata overwriting unit 24a and a metadata reading unit 24b.
In response to the overwrite command from the metadata check means 23, the metadata overwrite means 24a reads the duplicate metadata included in the file accumulated by the file accumulation means 22, and determines whether or not the duplicate metadata is missing. Judgment. The metadata overwriting means 24a sequentially reads the duplicate metadata contained in the file accumulated by the file accumulation means 22 from the beginning of the file based on the position information contained in the fragment information (for example, the duplicate metadata in FIG. 2). 1 to 3 are read in order). The metadata overwriting means 24a determines that the duplicate metadata is missing when all the duplicate metadata cannot be read. If any one of the metadata can be read, the duplicate metadata is obtained. Is determined not to be missing.

  When the metadata overwriting means 24a determines that the duplicate metadata is not missing, the metadata overwrite means 24a overwrites the metadata with the duplicate metadata that has been read, and sends a metadata read command to the metadata read means 24b that will be described later. Output. On the other hand, when the metadata overwriting means 24a determines that the duplicate metadata is missing, for example, the reproduction process of the media data is interrupted. As described above, the metadata overwriting means 24a quickly reads out the duplicate metadata based on the position information, so that the speed of the metadata repair process is improved.

  The metadata reading means 24b reads metadata included in the file stored by the file storage means 22 in response to a read command from the metadata check means 23 or the metadata overwrite means 24a. Then, the metadata reading unit 24b outputs the read metadata to the media data reproducing unit 25 described later.

  The media data reproducing unit 25 refers to the metadata output by the metadata reading unit 24b and reproduces the divided media data. In the present embodiment, the media data playback means 25 plays back the divided media data in order from the beginning of the file. Here, as shown in FIG. 2 (a), since the fragment ID and the duplicate metadata are inserted between the divided media data, the media data reproduction means 25 uses the fragment ID and the duplicate metadata. Skip and play. Further, when the fragment ID is added, the media data reproducing means 25 refers to the fragment ID to obtain the position of each divided media data in the file, and quickly reads and reproduces each divided media data. It can be performed.

  The file receiving device 2 can be configured by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an HDD (Hard Disk Drive). Further, the file receiving device 2 may include an antenna (not shown) for receiving BS digital broadcasting or mobile broadcasting.

[Operation of file receiver]
With reference to FIG. 5, the operation of the file receiving apparatus of FIG. 4 will be described (see FIG. 4 as appropriate). FIG. 5 is a flowchart showing the operation of the file receiving apparatus of FIG.

  First, the file receiving device 2 uses the file receiving means 21 via the unidirectional communication line M to place the metadata at the head, the duplicate metadata is arranged before the divided media data, and the duplicate metadata is at regular intervals. The multiplexed file is received (step S21: file receiving step). Then, the file receiving device 2 stores the file received by the file receiving unit 21 by the file storing unit 22 (step S22: file storing step).

  Subsequent to the process of step S22, the file receiving apparatus 2 determines whether the metadata included in the file stored by the file storage unit 22 is missing by the metadata check unit 23 (step S23: metadata). Check step).

  Following the processing of step S23, the file receiving apparatus 2 reads the duplicate metadata included in the file accumulated by the file accumulation means 22 by the metadata overwrite means 24a, and determines whether or not the duplicate metadata is missing. Determine. When the metadata overwriting unit 24a determines that the duplicate metadata is not missing, the file reception device 2 overwrites the metadata with the duplicate metadata that has been read (step S24: metadata restoration step).

  Subsequent to the processing of step S24, the file receiving device 2 reads the metadata included in the file stored by the file storage unit 22 by the metadata reading unit 24b, and the metadata reading unit 24b by the media data reproduction unit 25. The divided media data is reproduced with reference to the output metadata (step S25: content reproduction step).

  According to this embodiment, media data can be played back unless data error or data loss occurs in metadata and all duplicate metadata, so even if a data error or data loss occurs in a unidirectional communication line, It can make the download service easier to maintain. In particular, the present invention is effective when a video having a large media data size is downloaded.

<Modification>
In the present embodiment, the file receiving apparatus 2 has been described as storing files with the data structure shown in FIG. 2A, but the present invention is not limited to this. For example, when the metadata checking unit 23 determines that the metadata is not missing, or when the metadata overwriting unit 24a overwrites the metadata, the following processing is performed. The media data reproduction unit 25 removes the fragment ID and the duplicate metadata from the file stored by the file storage unit 22 and concatenates the divided media data. As shown in FIG. 6, the metadata, one piece of media data, A file containing Then, the media data reproducing means 25 reproduces this one piece of media data. As a result, the file receiving device 2 saves the capacity of the file storage unit 22 and does not need to skip the fragment ID and the duplicate metadata when reproducing the media data, thereby simplifying the reproduction process.

It is a block diagram which shows the structure of the file transmission apparatus which concerns on this embodiment of this invention. It is a figure which shows the data structure of the file in this invention, (a) is a figure which shows the data structure of the whole file, (b) is a figure which shows the data structure of the metadata contained in a file. It is a flowchart which shows operation | movement of the file transmission apparatus of FIG. It is a block diagram which shows the structure of the file receiver which concerns on this embodiment of this invention. It is a flowchart which shows operation | movement of the file receiver of FIG. It is a figure which shows the data structure of the file containing the conventional media data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 File transmission apparatus 11 Fragment information generation means (division control information generation means)
13 Fragmenting means (media data dividing means)
15 Metadata replication means 17 Containerization means (multiplexing means)
19 File transmission means 2 File reception device 21 File reception means 22 File storage means 23 Metadata check means (metadata loss judgment means)
24 metadata restoration means 24a metadata overwriting means 24b metadata reading means 25 media data reproducing means M unidirectional communication line

Claims (4)

In a download system including a file transmission device that transmits a file including media data that is the content of content via a unidirectional communication line that is digital broadcasting or multicast communication, and one or more file reception devices that receive the file A file transmission device,
A division control information generating means for calculating a division number for dividing the media data into a preset size and generating division control information including the division number;
Media data dividing means for generating the divided media data by dividing the media data into the number of divisions based on the division control information generated by the division control information generating means.
Metadata necessary for reproduction of the media data is input, the division control information is added to the metadata, and the metadata to which the division control information is added is duplicated to make the same number of duplicate metadata as the division number. Metadata replication means for generating data;
Multiplexing means for starting the metadata, arranging the duplicate metadata before the divided media data, and multiplexing the duplicate metadata so as to be at regular intervals to generate the file;
File transmitting means for transmitting the file generated by the multiplexing means to the file receiving device;
A file transmission device comprising:   2. The metadata copying unit according to claim 1, wherein the metadata and the division control information added to the duplicate metadata include position information indicating a position of the duplicate metadata in the file. File transmission device. In a download system including a file transmission device that transmits a file including media data that is the content of content via a unidirectional communication line that is digital broadcasting or multicast communication, and one or more file reception devices that receive the file A file receiving device,
Duplicate metadata, in which the metadata is duplicated, is arranged before the divided media data obtained by dividing the media data, with the metadata necessary for the reproduction of the media data at the head, and the duplicate metadata is arranged at regular intervals. File receiving means for receiving the file multiplexed so that
File storage means for storing the file received by the file receiving means;
Metadata loss determination means for determining whether or not the metadata included in the file accumulated by the file accumulation means is missing;
When it is determined that the metadata is missing, reading the duplicate metadata included in the file accumulated by the file accumulating unit, and determining whether the duplicate metadata is missing, Metadata restoration means for overwriting the metadata included in the file accumulated by the file accumulation means with the duplicate metadata determined not to be missing,
Media data reproducing means for referring to the metadata and reproducing the divided media data;
A file receiving apparatus comprising: The file receiving means includes division control information including position information indicating a position of the duplicate metadata in the file in the metadata and the duplicate metadata included in the received file,
The said metadata restoration means reads the said replication metadata contained in the said file which the said file storage means accumulate | stored based on the said positional information contained in the said division | segmentation control information. File receiving device.

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