JP2009038452A - Communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide communication equipment which can reduce the resources being used when a list of content data is opened on the network. <P>SOLUTION: The communication equipment includes means for managing one or more content data stored in a storage medium by a first hierarchic structure having one or more hierarchy, means for classifying the content data into a second hierarchic structure while maintaining the first hierarchic structure in the storage medium managed by the management means, means for opening a list of content data to other device on the network according to the second hierarchic structure classified by the classification means, and a memory for temporarily storing the list of content data opened by the list publishing means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication device that communicates with other devices via a network.

  In recent years, it has become possible to distribute recorded programs (moving image data), taken pictures (still image data), recorded music (audio data), etc. to other devices connected to the home network. It is coming. One of the technologies for this purpose is UPnP (Universal Plug and Play), which is a device control protocol for IP networks, and a specification called UPnP AV Architecture is defined in UPnP Forum as a specification especially for AV devices. The standard defined by the industry standard group DLNA (Digital Living Network Alliance) is also based on this UPnP, and products complying with the DLNA standard are becoming widespread.

  In UPnP AV Architecture, UPnP Media Server Device (hereinafter also referred to as a media server) is a server that implements a controlled function, and UPnP Media Renderer (hereinafter also referred to as a media renderer) is a device that reproduces content data provided / transmitted by the media server. However, Media Server Control Point (hereinafter also referred to as a control point) is defined as a client that implements a control function for controlling the media server.

  In particular, UPnP CDS (Content Directory Service, for example, non-patented) is used as an elemental technology for publishing a list of content data (audio data, still image data, moving image data, etc.) that can be provided by a media server. Reference 1) is defined. CDS is a service that provides a content list that is a list of content data that can be provided by a media server. In the UPnP CDS standard, the format of a content list, a method by which a control point acquires a content list, and the like are determined. .

In CDS, information indicating metadata of content data such as URI (Uniform Resource Indicator) for acquiring content data, content title, recording time, etc. is disclosed in an XML (Extensible Markup Language) format having a hierarchical structure. . At this time, the hierarchical structure disclosed by the CDS is usually the same hierarchical structure as the directory structure (hierarchical structure) of content data stored in the storage medium.
Alan Presser, 16 others, “Content Directory: 2 Service Template Version 1.01”, [online], March 31, 2006, UPnP Forum, [Search July 24, 2007], Internet (URL: http: //www.upnp.org/specs/av/UPnP-av-ContentDirectory-v2-Service-20060531.pdf)

  However, for example, in a digital camera or the like, if a user takes a large number of photos at a time, a large number of photo content data is stored in one directory. At this time, in an apparatus that is published in the same hierarchical structure as the directory structure, a large number of pieces of content data information are published side by side in a group (container: Container) corresponding to the directory. For this reason, an apparatus for mounting the CDS requires a large amount of processing time and also requires a large amount of memory capacity for temporarily storing the content list. Further, on the device side that implements the control point for acquiring the published content list, it takes a long time to acquire / process the list, and it is necessary to secure a large temporary storage capacity of the memory.

  Accordingly, an object of the present invention is to provide a communication device that can reduce resources used when a list of content data is published on a network.

  In order to achieve the above object, a communication apparatus according to the present invention includes a management unit that manages one or more content data stored in a storage medium in a first hierarchical structure having one or more layers, and the management unit manages Maintaining the first hierarchical structure in the storage medium while classifying the content data into a second hierarchical structure, and the content data according to the second hierarchical structure classified by the classification means A list publishing means for publishing the list of the content data to the other devices on the network, a memory for temporarily storing the list of the content data published by the list publishing means, and the list published by the list publishing means as the list Reading means for reading content data from the storage medium in response to a request from the other device, and the content read by the reading means And a sending means for sending over data to the other device.

  ADVANTAGE OF THE INVENTION According to this invention, the communication apparatus which can reduce the resource used when publishing the list of content data on a network can be provided.

  The communication apparatus of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a communication system in which a recording apparatus which is an embodiment of a communication apparatus of the present invention is used. The communication system 1 includes a recording device 10 (communication device) that publishes content data such as still image data and moving image data over a network, and playback devices 20 and 30 that receive and reproduce the content data. . Note that the recording device 10 and the playback devices 20 and 30 are connected to each other by a network 40 in which communication is performed by TCP (Transmission Control Protocol) / IP (Internet Protocol).

  Here, the recording apparatus 10 of the present embodiment is a digital camera that captures images and generates still image data and moving image data, for example. The recording device 10 also stores content data such as captured still image data and moving image data, and a list of information relating to the content data (a list having information relating to each content data as an item; hereinafter also referred to as a content list). It also has a function to publish over 40.

  The playback devices 20 and 30 are, for example, digital televisions and HDD players. The playback devices 20 and 30 receive the content data from the recording device 10 and output the video of the video signal obtained by playback to a display unit or an audio output unit, or an external display device or audio output device that the playback device 20 or 30 has. It has a function. In addition, the recording apparatus 10 has a function of acquiring a list of content data that can be provided from the recording apparatus 10.

  The network 40 that connects the recording device 10 and the playback devices 20 and 30 is, for example, a LAN (Local Area Network). In this embodiment, the network 40 is composed of three devices. However, the present invention is not limited to this, and a configuration including only the recording device 10 and the playback device 20 or four or more devices are connected to the network 40. It may be a configuration. Hereinafter, a description will be given mainly between the recording device 10 and the playback device 20.

  Here, the recording device 10 and the playback device 20 are AV (Audio / Video) devices corresponding to UPnP, respectively. In UPnP, a specification called UPnP AV Architecture is defined for AV devices. In this UPnP AV Architecture, a device (Device), a service (Service), and a control point (Control Point) are defined as basic network configurations. A device is a device that supports UPnP AV, and a service is a minimum unit that represents a function provided by the device. Each device is a controlled device having at least one service. The control point controls and uses a service that the device has. A single device can have a plurality of device functions, and an apparatus in which a control point and a device are integrated can be considered.

  In UPnP AV Architecture, UPnP Media Service (media server) is defined as a server device that implements a controlled function and provides content data. In this communication system 1, the recording device 10 functions as a media server. The recording apparatus 10 according to the present embodiment, which is a media server, provides a CDS (Content Directory Service) that is a service for publishing a content list. CDS is defined by UPnP AV.

  In UPnP AV Architecture, UPnP Media Renderer (media renderer) is defined as a device for playing back content data transmitted by a media server. However, in this communication system 1, the playback device 20 functions as a media renderer.

  Furthermore, in UPnP AV Architecture, control points for controlling and using services provided by the media server are defined, but in the communication system 1, the playback device 20 functions as a control point. That is, the playback device 20 realizes two functions of a control point and a media renderer.

  Here, when the user acquires a content list of the recording device 10 that provides the CDS using the playback device 20 that is a control point, or the recording device 10 that is a media server using the playback device 20 that is a media renderer. A general flow in the case of acquiring and reproducing content data from will be briefly described with reference to FIG.

FIG. 2A is a diagram showing a flow of processing when the playback apparatus 20 acquires a content list from the recording apparatus 10 which is a media server that provides CDS.
First, the playback device 20 serving as a control point transmits a Browse action (browsing request) requesting acquisition of a content list to the recording device 10 that provides CDS (S21). Then, as a response, the recording apparatus 10 that provides the CDS transmits the content list as a Browse Response (S22). Accordingly, the playback device 20 can acquire information on content data that can be provided by the recording device 10 (for example, title, class, URI (Uniform Resource Identifier) information, etc.).

  Here, the CDS provides a content list in a hierarchical structure. Normally, in a single response, a child hierarchy (corresponding to a directory, a container to be described later) included in one hierarchy and content data information (item to be described later) ) Only. In the present embodiment, the number of items (items to be described later) included in one group (container to be described later) is limited to a predetermined number. Resources such as processing load can be reduced. The structure of the content list provided by the CDS will be described in detail later.

  In the example of FIG. 2A, the Browse action is used as a method for acquiring the content list. However, the playback apparatus 20 can also acquire the content list from the recording apparatus 10 by the Search action. In the following description, the playback device 20 uses a Browse action as an action for acquiring a content list. However, a Search action may be used.

  Next, the flow of processing when the playback device 20 acquires content data for playback will be described with reference to FIG. FIG. 2B is a diagram showing a processing flow when the playback device 20 acquires content data from the recording device 10.

  The playback device 20 selects one content data from the content list acquired by the process described with reference to FIG. The playback device 20 that is a media renderer and a control point sends a predetermined communication protocol (HTTP (HyperText Transport in the example of FIG. 2B)) to the URI described in the item of the selected content data in the content list. Protocol) GET) transmits a content data acquisition request (S23). As a response, the recording device 10 that is a media server transmits the content data (S24). Thereby, the reproducing | regenerating apparatus 20 can reproduce | regenerate the acquired content data. The communication protocol is not limited to HTTP, and RTP (Realtime Transport Protocol) or the like can also be used.

Next, the configuration of the recording apparatus 10 will be described with reference to FIG. FIG. 3 is a diagram illustrating the configuration of the recording apparatus 10.
The recording apparatus 10 includes a control unit 101, an imaging unit 102, a content recording unit 103, a storage medium 104, a content management unit 105, a virtual classification unit 106, a content disclosure unit 107, a RAM 108, and a communication unit 109. And a content transfer unit 111 and a content acquisition unit 112.

  The control unit 101 performs overall control of each component constituting the recording apparatus 10. In particular, each of the content management unit 105, the content transfer unit 111, and the like when creating and transmitting a content list, transmitting content data, and the like according to an action (request) received from the playback unit 20 received by the communication unit 109, for example. Take control over the configuration.

  The imaging unit 102 converts the light of the subject image into an electrical pixel signal corresponding to the amount of incident light, converts the electrical pixel signal into a digital signal, and performs a predetermined encoding method (JPG, BMP, MPEG). -2 etc.) image data. This image data may be still image data or moving image data, but in the present embodiment, it is assumed that it is mainly still image data.

The content recording unit 103 records the image data created by the imaging unit 102 by imaging the subject in the storage medium 104.
The storage medium 104 stores a plurality of content data such as a plurality of image data created by imaging with the imaging unit 102. The content data includes audio data and the like in addition to still image data and moving image data captured by the imaging unit 102. The storage medium 104 is, for example, an HDD (Hard Disk Drive) or a memory card, and may be a built-in storage medium or a removable portable storage medium.

  The content management unit 105 manages each content data stored in the storage medium 104. In particular, the management of metadata such as the file name, recording time, recording time, and other genre information of each content data is performed and passed to the virtual classification unit 106 as necessary. At this time, each content data in the storage medium 104 is managed in a group having a hierarchical structure called a directory (sometimes referred to as a folder). In this hierarchical structure, each directory is a group having zero or more files (that is, content data) and directories as children. The directory structure managed by the content management unit 105 of this embodiment will be described later with reference to FIG.

  The virtual classification unit 106 creates a hierarchical structure of content lists based on the directory structure managed by the content management unit 105. The content publishing unit 107 functioning as a CDS publishes this content list according to the hierarchical structure classified by the virtual classification unit 106.

  In CDS, content data information is managed by a container (container) and an item (item). One item corresponds to one content data and is defined as an XML element. On the other hand, a container is defined as an XML element that can have items and containers as children. That is, in a typical file system (directory structure), a container corresponds to a directory and an item corresponds to a file.

  The virtual classification unit 106 according to the present embodiment performs classification so that the number of children (containers and items) in one container is equal to or less than a predetermined number, and the hierarchical structure (container structure) of the content list is determined. create. In particular, when the number of contents in one container becomes large (when the number exceeds a predetermined number), it is divided into a plurality of containers. In addition, as a method of dividing, it may be previously set to a child constant or less. If a recording time range is specified or genre information or the like can be used, the number of contents is narrowed down using these information. You can also do it. In this embodiment, after narrowing down by shooting date and time information, classification is performed so as to be equal to or less than a predetermined child constant.

  Even when the virtual classification unit 106 is divided into a plurality of containers, the hierarchical structure in the storage medium 104 managed by the content management unit 105 is maintained. That is, the directory structure of content data is managed independently from the hierarchical structure of the content list. Details of the container structure created by the virtual classification unit 106 will be described later with reference to FIG.

  The content publishing unit 107 has a function of publishing a content list as a CDS, and transmits the content list in a hierarchical structure in response to a request from the playback device 20 such as a Browse action (S21 in FIG. 2A). This hierarchical structure is a container structure classified by the virtual classification unit 106. Details of the content list published by the content publishing unit 107 will be described later with reference to FIG.

  A RAM (Random Access Memory) 108 is a volatile storage medium that can be read and written and temporarily holds data. In particular, the RAM 108 has a function of temporarily storing the content list when the content publishing unit 107 publishes the content list.

  The communication unit 109 is a communication interface for communicating by TCP / IP in the network 40, and a Browse action (FIG. 2A) for requesting browsing of a content list transmitted from the playback device 20 or content data. The acquisition request (S23 in FIG. 2B) is received by the communication unit 109. Similarly, the Browse Response including the content list (S22 in FIG. 2A) and the content data to be transmitted (S24 in FIG. 2B) are transmitted from the communication unit 109 to the playback device 20.

  In response to the content data acquisition request (S23 in FIG. 2B) received by the communication unit 109, the content transfer unit 111 performs a process of transmitting the requested content data. The content data transmitted at this time is read from the storage medium 104 by the content acquisition unit 112.

  Next, the relationship between the directory structure in which the content data in the storage medium 104 is managed and the hierarchical structure of the content list in the playback device 20 of the present embodiment will be described with reference to FIGS.

  FIG. 4 is a diagram illustrating an example of a directory structure when the content management unit 105 manages content data in the storage medium 104. In the example of the directory structure 400 of FIG. 4, the ROOT directory 401 (root) has a directory 402 named “DCIM” as a child. Furthermore, the DCIM directory 402 has a directory 403 named “100TSB” and a directory 404 named “101TSB” as children.

  A directory 403 named “100TSB” is an image file 403A named “photo 001.jpg”, an image file 403B named “photo 002.jpg”, and “photo xxx.jpg”, which are still image content data. Have the image file 403M with the name of the child. At this time, the number of image files that the directory 403 can have for the child is not limited, and may be several thousand or more when the number is large.

  Similarly, the directory 404 named “101TSB” has an image file 404A named “photo yyy.jpg” and an image file 404N named “photo zzz.jpg”, which are still image content data. Similarly for the directory 404, the number of image files that a child can have is not particularly limited.

  The virtual classification unit 106 classifies the files / directories managed in the directory structure 400 so that the number of children in each group (directory) is equal to or less than a certain number, and creates a container structure for the content list. Hereinafter, description will be made assuming that the virtual classification unit 106 performs classification so that the number of children in each group is 10 or less.

  FIG. 5 is a diagram illustrating an example of a container structure of a content list classified by the virtual classification unit 106. In the content list 500 of FIG. 5, the container 501 is the root container. This container 501 corresponds to the directory 402 (name: “DCIM”) in the directory structure 400 shown in FIG.

  The container 501 has a container 502 named “101TSB” and a container 503 named “101TSB” as children. The container 502 corresponds to the directory 403 (name: 100TSB) in the directory structure 400 shown in FIG. 4, and the container 503 corresponds to the directory 404 (name: 101TSB) in the directory structure 400 shown in FIG.

  When the number of files 403A to 403M stored in the directory 403 exceeds a predetermined number (for example, 10), the virtual classification unit 106 has items corresponding to these files as children, The containers 502-1 to 502-M are created so that the number is equal to or less than the predetermined number. In the case of still image data such as a photograph, each content data (file) often has information on imaging date / time (creation date / time) as metadata. The virtual classification unit 106 according to the present exemplary embodiment performs temporary classification based on the date of image capture, and classifies the image so that it is less than or equal to the predetermined number when the predetermined number is exceeded even after classification based on the image capture date / time.

  More specifically, the container 502-1 named “20070101-1” and the container 502-2 named “20070101-2” store items corresponding to the content data of the imaging date January 1, 2007. The items that are held as children are classified so that the number of items that each container has as children is 10 or less, which is a predetermined number.

  In the example of FIG. 5, the container 502-1 includes an item 502-1a corresponding to the content data 403A (“photo 001.jpg”), an item 502-1b corresponding to the content data 403B (“photo 002.jpg”), The item 502-1m corresponding to the content data ("Picture 010.jpg") not shown in FIG. 4 is held as a child, and the number of these children is 10 or less. Similarly, the container 502-2 corresponds to the item 502-2a corresponding to the content data not shown in FIG. 4 (“photo 011.jpg”) and the content data not shown in FIG. 4 (“photo 01x.jpg”). Having items 502-2n as children, the number of these children will be 10 or less.

  Containers that are children of containers 502-3 (name is “200701115-1”), 502-M (name is “xxxxxxxx-x”), and container 503 (corresponding to the directory 404 as described above, name is “101TSB”) Similarly to the containers 502-1 and 502-2, the virtual classification unit 106 classifies 503-1 (name is “20070702-1”) so that the number of these children is equal to or less than a predetermined number.

  FIG. 6 is a diagram illustrating an example of a content list published by the content publishing unit 107 in accordance with the container structure created by the virtual classification unit 106. In the example of FIG. 6, the entire content list is shown, but only the container or item specified by the Browse request received from the playback device 20 can be transmitted as the Browse Response.

  As described above, the content publishing unit 107 operating as a CDS publishes the content list 500 in the XML format. Each element (Element) of XML corresponds to a container (corresponding to a directory) and an item (corresponding to content data). The container structure is reflected as a parent-child relationship between XML elements.

  In the example of FIG. 6, a container 501 described as a container element has “0” as a value (described as an id attribute (Attribute)) as a value, and a class (described as an upnp: class element as a child element) is an object. . It is container. Furthermore, the container element corresponding to the container 501 has the container element 2 corresponding to the containers 502 and 503 as child elements, and it can be seen that the container 501 has the containers 502 and 503 as children.

  The container 502 expressed as a container element has “1” as a value (described as an id attribute), a parent ID (described as a parentID attribute) is “0”, and the number of children (childCount attribute). It can be seen that it is 10). Further, the name of the container 502 is “100TSB” (described by a dc: title element that is a child element), and a class (described by an upnp: class element that is a child element) is object. You can also see that it is a container.

  Further, a container element indicating the container 502 includes a container element corresponding to the container 502-1 and a container element corresponding to the container 502-2 as child elements. Thereby, it can be seen that the container 502 has the containers 502-1 and 502-2 as children.

  The container 502-1 represented as a container element has “2” as a value of id (described as an id attribute), a parent ID value (described as a patentID attribute) of “1”, and the number of children ( It is shown that “childCount attribute” is 10. Further, the name of the container 502-1 (described by a dc: title element that is a child element) is “20070101-1”, and a class (described by an upnp: class element that is a child element) is object. It also indicates that it is a container.

  Further, the container element indicating the container 502-1 has an item element corresponding to the item 502-1a, an item element corresponding to the item 502-1b, and an item element corresponding to the item 502-1m as child elements. It can be seen that the container 502-1 has items 502-1a, 502-1b, and 502-1m as children, respectively.

  The item element 502-1a indicating the item 502-1a has “2-1” as a value of id (described as an id attribute), and the value of the parent ID (described as a patentID attribute) is “2”. Show. Furthermore, the name of the item 502-1a (described as a child element dc: title element) is “photo 001”, and the imaging date (also described as a child element dc: date element) is 2007-01-. 01T0773020, and the class (described as a child element of upnp: class element) is object. item. imageItem, the communication protocol information for acquiring the corresponding content data (described as a protocolInfo attribute in the res element as a child element) is “http-get: *: image / jpg: *”, and the corresponding content It can be seen that the URI for obtaining data (also described as a child text in the res element) is “http://192.168.0.1:58849/photo 001.jpg”.

  Similarly, the item element 502-1b indicating the item 502-1b has “2-2” as a value of id (described as an id attribute), and the value of the parent ID (described as a patentID attribute) is “2”. It shows that there is. Furthermore, the name of the item 502-1b (described as a child element dc: title element) is “Photo 002”, and the imaging date (also described as a child element dc: date element) is 2007-01-. 01T073025, and the class (described as a child element of upnp: class element) is object. item. imageItem, the communication protocol information for acquiring the corresponding content data (described as a protocolInfo attribute in the res element as a child element) is “http-get: *: image / jpg: *”, and the corresponding content It can be seen that the URI for obtaining the data (also described as a child text in the res element) is “http://192.168.0.1:58849/photo002.jpg”.

For other containers and items whose description is omitted, content data information is described in the content list 500 in the same manner.
As is apparent from FIG. 6, since there is a large amount of description related to one item or container in the CDS, if it is attempted to transmit a content list for all content data stored in the storage medium 104 at once, the RAM 108 In addition, a large amount of temporary storage capacity is required, and a CPU or the like needs a lot of calculation processing, so that the storage device 10 needs to have a large resource. However, in this embodiment, since the number of children included in one container (group) can be classified by the virtual classification unit 106 so that it is equal to or less than a predetermined number and released for each container (group), Even with small resources, the content list can be published as a CDS.

Next, the flow of processing for creating and transmitting the content list 500 of the recording apparatus 10 according to the present embodiment will be described with reference to FIG.
When the communication unit 109 receives a browsing request (Browse action) from the playback device 30 (S701), the virtual classification unit 106 performs each of the directory structures 400 managed by the content management unit 105 under the control of the control unit 101. The containers are classified so that the number of children (items and containers) in the container is a certain number or less, and a container structure having a hierarchical structure is created (for example, see FIG. 5). At this time, it is assumed that the directory structure 400 in the storage medium 104 managed by the content management unit 105 is maintained, and what is one group in the directory structure 400 is divided into a plurality of contents in the container structure of the content list 500. However, the directory structure 400 is not changed.

  The content publishing unit 107 publishes the content list 500 in a hierarchical structure according to the description of XML shown in FIG. 6 according to the container structure created by the virtual classification unit 106 (S703). At this time, as described above, only the child (container / item) under one content can be transmitted, and the number of children can be reduced to a predetermined number or less, so the recording apparatus 10 has only a relatively small resource. Even so, it can be implemented.

In addition, on the playback apparatus 20 side, it is possible to reduce the acquisition time of the content list 500, the processing time, the required storage capacity, and the like.
Also, as shown in FIG. 7, by performing virtual classification of the container structure at the time of receiving the Browse action, for example, even when content data is newly added, it is possible to flexibly cope with it. Become.

  Further, the content publishing unit 107 of this embodiment publishes still image data captured by the imaging unit 102 as content data. In particular, still images have a relatively small amount of data, and thousands of data can often be stored in the storage medium 104. In such a case, since the same number of items (items) of the content list published by the content publishing unit 107 are required, the number of items / containers included in one group is set to a predetermined number as in this embodiment. The following effects become remarkable.

  Furthermore, in the case of music data or the like, it is possible to classify in multiple stages using various information such as album name, artist name, genre, etc. to reduce the number of items in one group, but still image data In this case, since there is no information suitable for classification other than the imaging date and time, it is difficult to dramatically reduce the number of items in the group even if classification is performed using only attribute information. In the present embodiment, when the number of items in the group (container) classified by the shooting date and time exceeds a predetermined number, another group (container) is forcibly created, so that it is released at a time. The number of items in the content list 500 can be surely reduced.

  In the example of FIG. 7, the virtual classification unit 106 performs the virtual classification of the container structure when the Browse request is received. However, the present invention is not limited to this. For example, classification may be performed in advance. In this case, since it is not necessary to perform the classification work when receiving the Browse action, the responsiveness to the playback device 20 can be improved.

1 is an example of a communication system in which a recording apparatus according to Embodiment 1 of the present invention is used. FIG. 4 is a diagram illustrating a processing flow when the recording apparatus according to the first embodiment of the present invention communicates with another communication apparatus. 1 is a diagram illustrating a configuration of a recording apparatus according to a first embodiment of the invention. FIG. 3 is a diagram illustrating an example of a directory structure of content data stored in a storage medium of the recording apparatus according to the first embodiment of the invention. FIG. 3 is a diagram illustrating an example of a content list container structure disclosed by the recording apparatus according to the first embodiment of the invention. FIG. 3 is a diagram illustrating an example of a content list disclosed by the recording apparatus according to the first embodiment of the invention. FIG. 3 is a diagram illustrating a flow of processing related to content list disclosure of the recording apparatus according to the first embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Communication system 10 ... Recording apparatus 20, 30 ... Playback apparatus 40 ... Network 101 ... Control part 102 ... Imaging part 103 ... Content recording part 104 ... Storage medium 105 ... Content management unit 106 ... Virtual classification unit 107 ... Content disclosure unit 108 ... RAM
109: Communication unit 111 ... Content transfer unit 112 ... Content acquisition unit 400 ... Directory structure 401, 402, 403, 404 ... Directory 403A, 403B, 403M, 404A, 404N ... File (Content data)
501, 502, 502-1, 502-2, 502-3, 502-M... Container 502-1a, 502-1b, 502-1m, 502-2a, 502-2n,... Item

Claims (6)

Management means for managing one or more content data stored in the storage medium in a first hierarchical structure having one or more hierarchies;
Classification means for classifying the content data into a second hierarchical structure while maintaining the first hierarchical structure in the storage medium managed by the management means;
List publishing means for publishing the list of content data to other devices on the network according to the second hierarchical structure classified by the classification means;
A memory for temporarily storing the list of the content data published by the list publication means;
Reading means for reading the content data published as the list by the list publishing means from the storage medium in response to a request from the other device;
A communication device comprising: transmission means for transmitting the content data read by the reading means to the other device. 2. The communication according to claim 1, wherein the classifying unit classifies the second hierarchical structure so that the number of the content data to be released at once as the list by the list publishing unit is a predetermined number or less. apparatus. The classification means includes a plurality of pieces of one or more pieces of content data managed as one group in the first hierarchical structure in the second hierarchical structure so that the number of content data in each group is a predetermined number or less. The communication apparatus according to claim 1, wherein the communication apparatus is classified as a group. It further comprises imaging means for generating image data by imaging,
2. The communication apparatus according to claim 1, wherein the content data stored in the storage medium includes at least image data captured by the imaging unit. Receiving means for receiving a browsing request for requesting browsing of the list from the other device;
The communication device according to claim 1, wherein the classification unit classifies the browsing request into the second hierarchical structure when the receiving unit receives the browsing request from the other device. Receiving means for receiving a browsing request for requesting browsing of the list from the other device;
2. The communication apparatus according to claim 1, wherein the list disclosing means discloses the list classified in advance by the classification means to the other apparatus.

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