Patent Publication Number: US-9894391-B2

Title: Distribution management apparatus, distribution method, and program

Description:
FIELD 
     The present invention relates to a distribution management apparatus, a distribution method, and a program for distributing data to communication terminals via a communication network. 
     BACKGROUND 
     A technique of dividing web content and distributing it to a plurality of terminals is conventionally known. For example, Patent Literature 1 describes dividing one page of content into a menu portion and a content portion and distributing the menu portion to a terminal, e.g., a PDA, having small display/playback capabilities and distributing the content portion to a terminal, e.g., an Internet television, having large display/playback capabilities. 
     SUMMARY 
     Technical Problem 
     The technique described in Patent Literature 1 allows displaying the content portion in an easy-to-view fashion when the display/playback capabilities (e.g., resolution) of the terminal, to which the content portion is distributed, are sufficiently large relative to a data size of the content portion. However, when the whole content portion is displayed in a situation where the data size of the content portion is larger than the display/playback capabilities (e.g., resolution) of the terminal, a video is zoomed out and cannot be displayed in an easy-to-view fashion. 
     The present invention has been made in view of the above and primarily aims at providing a distribution management apparatus, a distribution method, and a program capable of causing communication terminals to display a whole video of content and simultaneously to display a desired portion of the content in an easy-to-view fashion. 
     Solution to Problem 
     To solve the above problem and achieve the object, the present invention includes a generator configured to generate still-picture data from content data; a converter configured to convert the still-picture data into video data; and a distributer configured to distribute the video data to each of a first communication terminal and a second communication terminal, the first communication terminal and the second communication being capable of playing back and displaying the video data. When first operation data indicating an operation of zooming into a partial region of the video data being played back and displayed on the first communication terminal is transmitted, the converter generates video data representing a partial region of the video data being played back and displayed on the first communication terminal, the partial region depending on display/playback capabilities of the second communication terminal, and the distributer distributes the video data representing the partial region generated by the converter to the second communication terminal. 
     Advantageous Effects of Invention 
     According to an aspect of the present invention, it is advantageously possible to cause communication terminals to display a whole video of content and simultaneously to display a desired portion of the content in an easy-to-view fashion. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram of a distribution system according to a present embodiment. 
         FIG. 2  is a conceptual view of attachment of a dongle to a communication terminal. 
         FIG. 3  is a conceptual diagram illustrating a basic distribution method. 
         FIG. 4  is a conceptual diagram of multi-display. 
         FIG. 5  is a conceptual diagram of zoom-in display exploiting the multi-display. 
         FIG. 6  is a diagram illustrating an example of hardware components of a distribution management apparatus. 
         FIG. 7  is a diagram illustrating an example of hardware components of the dongle. 
         FIG. 8  is a functional block diagram primarily illustrating functions of the distribution management apparatus. 
         FIG. 9  is a detailed diagram of an encoder bridge unit. 
         FIG. 10  is a functional block diagram illustrating functions of a converting unit. 
         FIG. 11  is a functional block diagram primarily illustrating functions of the communication terminal. 
         FIG. 12  is a functional block diagram illustrating functions of a terminal management apparatus. 
         FIG. 13  is a conceptual diagram of a distribution-destination selection menu screen. 
         FIG. 14  is a conceptual diagram of a terminal management table. 
         FIG. 15  is a conceptual diagram of an available-terminal management table. 
         FIG. 16  is a sequence diagram illustrating a basic distribution process of the distribution management apparatus. 
         FIG. 17  is a sequence diagram illustrating a time adjustment process carried out between the distribution management apparatus and the communication terminal. 
         FIG. 18  is a sequence diagram illustrating a channel-adaptive-control process performed on data transmitted from the distribution management apparatus to the communication terminal. 
         FIG. 19  is a sequence diagram illustrating a channel-adaptive-control process performed on data transmitted from the communication terminal to the distribution management apparatus. 
         FIG. 20  is a sequence diagram illustrating a multi-display process. 
         FIG. 21  is a sequence diagram illustrating the multi-display process. 
         FIG. 22  is a sequence diagram illustrating the multi-display process. 
         FIG. 23  is a sequence diagram illustrating a zoom-in process exploiting the multi-display. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An exemplary embodiment of a distribution management apparatus, distribution method, and a program according to the present invention is described in detail below with reference to the drawings. The embodiment in the following description is an application example, in which aspects of the present invention are applied to a distribution system configured to cause, by using cloud computing, a web browser (hereinafter, “browser”) and an encoder to be executed in conjunction with each other on a cloud, thereby transmitting video data, audio data, and the like to communication terminals. Note that “image” used herein encompasses a still picture and moving pictures. “Video” used herein basically refers to moving pictures and also encompasses still pictures provided when moving pictures are paused. “Still picture (audio)” denotes at least one of a still picture and audio. “Image (audio)” denotes at least one of an image and audio. “Video (audio)” denotes at least one of a video and audio. 
     Outline of Embodiment 
     An outline of the present embodiment is described first with reference to  FIG. 1 .  FIG. 1  is a schematic diagram of a distribution system  1  according to the present embodiment. 
     &lt;Outline of System Configuration&gt; 
     An outline of a configuration of the distribution system  1  is described first. As illustrated in  FIG. 1 , the distribution system  1  according to the present embodiment is constructed including a distribution management apparatus  2 , a plurality of communication terminals  5   a  to  5   f , a terminal management apparatus  7 , and a web server  8 . Hereinafter, “the communication terminal  5 ” denotes an arbitrary one of the plurality of communication terminals  5   a  to  5   f . Each of the distribution management apparatus  2 , the terminal management apparatus  7 , and the web server  8  is implemented on a server computer. 
     The communication terminals  5  are terminals for use by users receiving a service(s) provided by the distribution system  1 . Among them, the communication terminal  5   a  is a notebook PC (Personal Computer). The communication terminal  5   b  is a mobile terminal, such as a smartphone or a tablet terminal. The communication terminal  5   c  is an MFP (Multifunction Peripheral/Printer/Product), in which functions of copying, scanning, printing, and facsimile are combined. The communication terminal  5   d  is a projector. The communication terminal  5   e  is a television (video) conference terminal including a camera, a microphone, and a speaker. The communication terminal  5   f  is a digital whiteboard (interactive whiteboard) capable of electronic conversion of a character, a shape, and the like drawn by a user or the like. 
     The communication terminal  5  is not limited to such a terminal as those illustrated in  FIG. 1  and may alternatively be a device capable of communication via a communication network, e.g., the Internet. Examples of the device include a watch, a vending machine, a gas meter, a car navigation device, a video game console, an air conditioner, a lighting fixture, an independent camera, an independent microphone, and an independent speaker. 
     The distribution management apparatus  2 , the communication terminals  5 , the terminal management apparatus  7 , and the web server  8  can communicate via a communication network  9 , e.g., the Internet and a LAN (Local Area Network). The communication network  9  can include wireless communication networks including 3G (3rd Generation), WiMAX (Worldwide Interoperability for Microwave Access), and LTE (Long Term Evolution). 
     As in the case of, for example, the communication terminal  5   d , some of the communication terminals  5  may not have the function of communicating with other terminals and systems via the communication network  9 . However, inserting a dongle  99 , by a user, into an interface portion of USB (Universal Serial Bus), HDMI (registered trademark) (High-Definition Multimedia Interface), or the like of the communication terminal  5   d  as illustrated in  FIG. 2  enables the communication terminal  5   d  to communicate with other terminals and systems via the communication network  9 .  FIG. 2  is a conceptual view of attachment of the dongle  99  to the communication terminal. 
     The distribution management apparatus  2  includes, on a cloud, a browser  20 . A renderer function of the browser  20  allows acquiring a single or a plurality of pieces of content data described in a predetermined description language and performing rendering, thereby generating frame data as still-picture data, such as RGB (Red, Green, and Blue) bitmap data, and audio data, such as PCM (Pulse Code Modulation) data (in short, as still-picture (audio) data). The content data is data acquired from the web server  8 , an arbitrary communication terminal, or the like and includes image (audio) data in HTML (Hypertext Markup Language) or CSS (Cascading Style Sheets), image (audio) data in MP4 (MPEG-4), and audio data in AAC (Advanced Audio Coding). 
     The distribution management apparatus  2  further includes, on the cloud, an encoding unit  19 . The encoding unit  19  performs its function as an encoder, thereby converting frame data, each piece of which is still-picture (audio) data, into video (audio) data of a compression coding format including H.264 (MPEG-4 AVC), H.265, and Motion JPEG. 
     The terminal management apparatus  7  performs login authentication of the communication terminal  5 , management of contract information of the communication terminal  5 , and the like. The terminal management apparatus  7  further has a function as an SMTP (Simple Mail Transfer Protocol) server for transmitting electronic mails. The terminal management apparatus  7  can be implemented as a virtual machine running on a cloud service (IaaS (Infrastructure as a Service)), for example. It is desirable to operate the terminal management apparatus  7  in a multiplexed manner to provide services uninterruptedly even in case of unexpected incidents. 
     The browser  20  of the distribution management apparatus  2  enables real-time communication (RTC (Real-time Communication/Collaboration)). Furthermore, the encoding unit  19  of the distribution management apparatus  2  can encode, in real time, the video (audio) data generated by the browser  20  to output video (audio) data generated through conversion in conformance with the H.264 standard, for example. For this reason, processing performed by the distribution management apparatus  2  differs from that performed by, for example, a DVD player that reads out non-real-time video (audio) data recorded in a DVD and distributes it. 
     The communication terminal  5  may include a browser as does the distribution management apparatus  2 . At this time, the need for starting the browser of each of the communication terminals  5  can be eliminated by updating the browser  20  of the distribution management apparatus  2 . 
     &lt;Outlines of Various Distribution Methods&gt; 
     Outlines of various distribution methods in the distribution system  1  of the present embodiment are described below. 
     Basic Distribution 
       FIG. 3  is a conceptual diagram illustrating a basic distribution method in the distribution system  1  of the present embodiment. As illustrated in  FIG. 3 , in the distribution system  1 , the browser  20  of the distribution management apparatus  2  generates video (audio) data [A] by acquiring web content data [A] from the web server  8  and rendering it. An encoder bridge unit  30  performs encoding and the like on the video (audio) data [A] and distributes it to the communication terminal  5 . Thus, even if web content generated in HTML (Hypertext Markup Language), CSS (Cascading Style Sheets), or the like is rich, the web content is distributed as video (audio) data in H.264, MPEG-4, or the like. For this reason, even if the communication terminal  5  is a low-spec communication terminal, the communication terminal  5  can play back the video (audio) data smoothly. Furthermore, the distribution system  1  of the present embodiment enables to play back latest rich web content smoothly without the need of updating a browser that provides content to the local communication terminal  5  so long as the browser  20  of the distribution management apparatus  2  is updated. 
     Furthermore, the distribution system  1  can, by applying the above-described distribution method, distribute web content to the plurality of communication terminals  5  as video (audio) data as illustrated in  FIG. 4  and  FIG. 5 . The distribution methods illustrated in  FIG. 4  and  FIG. 5  are described below. 
     Multi-Display 
       FIG. 4  is a conceptual diagram of multi-display. As illustrated in  FIG. 4 , the single browser  20  of the distribution management apparatus  2  generates a single piece of video (audio) data [XYZ] by acquiring web content data [XYZ] from the web server  8  and rendering it. The encoder bridge unit  30  divides the single piece of video (audio) data [XYZ] into a plurality of pieces of video (audio) data [X], [Y], and [Z] and, thereafter, encodes them. Thereafter, the distribution management apparatus  2  distributes the dividing-resultant video (audio) data [X] to a communication terminal  5   f   1 . Similarly, the distribution management apparatus  2  distributes the dividing-resultant video (audio) data [Y] to a communication terminal  5   f   2  and distributes the dividing-resultant video (audio) data [Z] to a communication terminal  5   f   3 . Thus, because even if the web content data [XYZ] is of a landscape format, video is displayed by the plurality of communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  as being divided, an effect similar to that obtained by displaying a single video of a large size can be obtained by arranging the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  in a row. At this time, the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  are necessarily identical in display/playback capabilities (e.g., identical in resolution). Such a distribution method as that described above is referred to as, for example, “multi-display”. 
     Zoom-In Display Exploiting Multi-Display 
     With the multi-display, a single piece of video data generated by the browser  20  of the distribution management apparatus  2  can be distributed to the plurality of communication terminals  5  as different pieces of video data. By utilizing this, for example, it is possible to cause one of the plurality of communication terminals  5  to display a whole video and another one of the communication terminals  5  to display a portion of the video in a zoomed-in manner. For example, in a situation where the video data is large in size and the video on one of the communication terminals  5  displaying the whole video is hard to view, ease of viewing can be increased by causing another one of the communication terminals  5  to display a desired portion, which is zoomed in depending on display/playback capabilities (e.g., resolution) of the communication terminal  5 , of the video. 
       FIG. 5  is a conceptual diagram of zoom-in display exploiting the multi-display. As illustrated in  FIG. 5 , the single browser  20  of the distribution management apparatus  2  generates the single piece of video data [A] by acquiring the web content data [A] from the web server  8  and rendering it. The encoder bridge unit  30  encodes the video data [A]. The distribution management apparatus  2  distributes the encoded video data [A] to the plurality of communication terminals  5   f   1 ,  5   f   2 , and  5   f   3 . 
     Thereafter, when an operation of zooming into a portion of the video [A] being displayed is performed by a user on the communication terminal  5   f   1  and operation data [p] (first operation data) regarding the operation is transmitted from the communication terminal  5   f   1  to the distribution management apparatus  2 , the encoder bridge unit  30  performs a process of cutting out a partial region of the video data [A] generated by the browser  20 . The size of the region to be cut out depends on the display/playback capabilities (e.g., resolution) of the communication terminal  5   f   2 ,  5   f   3 . For example, in a case where the video data [A] is large in size and the video data [A] is resized (zoomed out) to display the whole video, a region of a size displayable on the communication terminal  5   f   2 ,  5   f   3  without resizing may be cut out. The encoder bridge unit  30  encodes each of the video data [A] generated by the browser  20 , video data [A′] representing a partial region cut out from the video data [A] depending on the display/playback capabilities (e.g., resolution) of the communication terminal  5   f   2 , and video data [A″] representing a partial region cut out from the video data [A] depending on the display/playback capabilities (e.g., resolution) of the communication terminal  5   f   3 . The distribution management apparatus  2  distributes the encoded video data [A] to the communication terminal  5   f   1 , the encoded video data [A′] to the communication terminal  5   f   2 , and the encoded video data [A″] to the communication terminal  5   f   3 . Thus, causing the communication terminal  5   f   1  to display the whole video while causing the communication terminals  5   f   1  and  5   f   2  to display the portion, which is zoomed in, of the video displayed on the communication terminal  5   f   1  can be achieved. 
     An initial position of the region to be cut out from the video is determined in advance. Both the distribution management apparatus  2  and the communication terminal  5   f   1  externally acquire the initial position and store it. Furthermore, the communication terminal  5   f   1  externally acquires the display/playback capabilities (e.g., resolution) of the communication terminals  5   f   2  and  5   f   3  and stores them. When an operation of zooming into a portion of the video data [A] being displayed is performed by a user, the communication terminal  5   f   1  displays a guide frame of a size that depends on the display/playback capabilities of the communication terminal  5   f   2  by superimposing the guide frame on the video data [A] at the initial position for the communication terminal  5   f   2 . Similarly, the communication terminal  5   f   1  displays a guide frame of a size that depends on the display/playback capabilities of the communication terminal  5   f   3  by superimposing the guide frame on the video data [A] at the initial position for the communication terminal  5   f   3 . At an early stage of the zoom-in display, videos of regions, which are surrounded by the guide frames and zoomed in, are displayed on the communication terminals  5   f   2  and  5   f   3 , respectively. 
     Thereafter, when an operation of moving the guide frame in the video [A] being displayed is performed by the user on the communication terminal  5   f   1  and operation data [p] (second operation data) indicating a distance and direction traveled by the guide frame is transmitted from the communication terminal  5   f   1  to the distribution management apparatus  2 , the encoder bridge unit  30  moves the position where the region is to be cut out from the video data [A] in accordance with the operation data [p]. For example, when the guide frame moved by the user is the guide frame associated with the communication terminal  5   f   2 , the encoder bridge unit  30  changes the position where the video data [A′] to be distributed to the communication terminal  5   f   2  is to be cut out in accordance with the operation data [p] indicating the distance and direction traveled by the guide frame. The encoder bridge unit  30  encodes the video data [A′] of the newly-cut-out region. Thereafter, the distribution management apparatus  2  distributes the video data [A′] of the newly-cut-out region to the communication terminal  5   f   2 . As a result, a video of the region surrounded by the guide frame moved by the user is displayed in a zoomed-in manner on the communication terminal  5   f   2 . Thus, by moving the guide frame to the region, which is desired to be zoomed in, on the video data [A] displayed on the communication terminal  5   f   1 , the user can cause the zoomed-in video of the region surrounded by the guide frame to be displayed on the other communication terminal  5   f   2 ,  5   f   3 . 
     At this time, the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  are not necessarily identical in the display/playback capabilities (e.g., identical in resolution). 
     Detailed Description of Embodiment 
     The embodiment is described in detail below with reference to  FIG. 6  to  FIG. 23 . 
     &lt;Hardware Components of Embodiment&gt; 
     Hardware components of the present embodiment are described below with reference to  FIG. 6  and  FIG. 7 .  FIG. 6  is a diagram of logical hardware components of the distribution management apparatus  2 .  FIG. 7  is a diagram of logical hardware components of the dongle  99 . Because the communication terminal  5 , the terminal management apparatus  7 , and the web server  8  are identical in hardware components to the distribution management apparatus  2  illustrated in  FIG. 6 , description thereof is omitted. 
     As illustrated in  FIG. 6 , the distribution management apparatus  2  includes a (host) CPU  201  for controlling operations of the whole distribution management apparatus  2 , a ROM  202  storing therein a program, such as an IPL, for use in driving the CPU  201 , a RAM  203  for use as a work area of the CPU  201 , an HDD  204  storing therein various data including programs, an HDC (Hard Disk Controller)  205  for controlling reading and writing various data from and to the HDD  204  under control of the CPU  201 , a media drive  207  for controlling reading and writing data from and to a recording media  206 , such as a flash memory, a display  208  for displaying various information, an I/F  209  for transmitting data using the communication network  9  and for connection with the dongle  99 , a keyboard  211 , a mouse  212 , a microphone  213 , a speaker  214 , a GPU (Graphics Processing Unit)  215 , a ROM  216  storing therein a program for use in driving the GPU  215 , a RAM  217  for use as a work area of the GPU  215 , and an expansion bus line  220  including an address bus and a data bus for electrically connecting the above-described elements. 
     Programs for the communication terminals, systems, and servers may be configured to be distributed as being recorded in computer-readable recording media, e.g., the recording media  206 , as installable- or executable-format files. 
     Next, the hardware components of the dongle  99  are described with reference to  FIG. 7 . As illustrated in  FIG. 7 , the dongle  99  includes a CPU  91  for controlling operations of the whole dongle  99 , a ROM  92  storing therein a basic input/output program, a RAM  93  for use as a work area of the CPU  91 , an EEPROM (Electrically Erasable and Programmable ROM)  94 , from and to which data is to be read and written under control of the CPU  91 , a GPU  95  for performing various image processing, a ROM  96   a  storing therein a program for use in driving the GPU  95 , a RAM  96   b  for use as a work area of the GPU  95 , an I/F  97  for connecting to the I/F  209  of the communication terminal  5 , an antenna  98   a , a communication unit  98  for carrying out communications using a short-distance wireless technology using the antenna  98   a , and a bus line  90  including an address bus and a data bus for electrically connecting the above-described elements. Examples of the short-distance wireless technology include the NFC (Near Field Communication) standards, Bluetooth (registered trademark), WiFi (Wireless Fidelity), and ZigBee (registered trademark). 
     &lt;Functional Components of Embodiment&gt; 
     Functional components of the present embodiment are described next with reference to  FIG. 8  to  FIG. 15 . 
     Functional Components of Distribution Management Apparatus 
       FIG. 8  is a functional block diagram primarily illustrating functions of the distribution management apparatus  2 . Although  FIG. 8  illustrates the functional components of the distribution management apparatus  2  distributing video (audio) data to the communication terminal  5   f   1 , the distribution management apparatus  2  distributing data to other destination than the communication terminal  5   f   1  has similar functional components. Although the distribution management apparatus  2  includes a plurality of distribution engine servers, for brevity of description, the following description is made by way of example, in which the distribution management apparatus  2  includes a single distribution engine server. 
     The distribution management apparatus  2  implements the functional components illustrated in  FIG. 8  with the hardware components illustrated in  FIG. 6  and a program. Specifically, the distribution management apparatus  2  includes the browser  20 , a transceiving unit  21 , a browser management unit  22 , a transmission FIFO  24 , a time management unit  25 , a time acquisition unit  26 , a channel-adaptive-control unit  27 , the encoder bridge unit  30 , a transceiving unit  31 , an index generation unit  32 , a reception FIFO  34 , a recognition unit  35 , a delay-information acquisition unit  37   a , a channel-adaptive-control unit  37   b , and a decoding unit  40 . The distribution management apparatus  2  further includes a storage unit  2000  implemented by the HDD  204  illustrated in  FIG. 6 . The storage unit  2000  stores therein recognition information, which is described later, output from the recognition unit  35 . Content data acquired by the browser  20  can be temporarily stored in the storage unit  2000  as a cache. 
     The browser  20 , which is one of the functional components, is a web browser that operates in the distribution management apparatus  2 . The browser  20  generates RGB data (or PCM (Pulse Code Modulation) data) by rendering content data, such as web content data. Furthermore, the browser  20  is capable of generating video (audio) data by playing back a video (audio) file using a plug-in, which is described later. The present embodiment is described on an assumption that data generated by the browser  20  is video (audio) data. The browser  20  is constantly updated to adapt to web contents getting richer. 
     In the distribution system  1  of the present embodiment, the distribution management apparatus  2  includes a plurality of the browsers  20 , from which a cloud browser for use in establishing a user session is to be selected. For brevity of description, an example, in which the single browser  20  is provided, is described below. 
     The browser  20  may include, for example, Media Player, Flash Player, JavaScript (registered trademark), CSS (Cascading Style Sheet), and an HTML (HyperText Markup Language) renderer. JavaScript (registered trademark) includes JavaScript according to a standard specification and JavaScript specific to the distribution system  1 . Media Player is a browser plug-in for playing back multimedia files, e.g., a video (audio) file, in the browser  20 . Flash Player is a browser plug-in for playing back Flash content within the browser  20 . The specific JavaScript (registered trademark) is a JavaScript (registered trademark) group providing APIs (Application Programming Interfaces) for services unique to the distribution system  1 . CSS is a mechanism for efficiently defining appearances and styles of web pages described in HTML. The HTML renderer is a web-kit-based HTML rendering engine. 
     The transceiving unit  21  transmits and receives various data, requests, and the like to and from the terminal management apparatus  7  and the web server  8 . For example, the transceiving unit  21  receives web content data from a content site of the web server  8  and passes it to the browser  20 . 
     The browser management unit  22  manages the browser  20  and the encoder bridge unit  30 . For example, the browser management unit  22  instructs the browser  20  and the encoder bridge unit  3  to start or stop running and assigns an encoder ID at start or stop. The encoder ID is identification information assigned by the browser management unit  22  for process management of the encoder bridge unit  30 . Furthermore, the browser management unit  22  assigns a browser ID each time the browser  20  is started and manages it. The browser ID is identification information for identification of the browser  20  assigned by the browser management unit  22  for process management of the browser  20 . 
     Furthermore, the browser management unit  22  acquires various operation data [p] from the communication terminal  5  via the transceiving unit  31  and outputs it to the browser  20 . The operation data [p] is data generated responsive to an operation event (e.g., an operation performed using the keyboard  211 , the mouse  212 , or the like and a stroke made with an electronic pen P) on the communication terminal  5 . When the communication terminal  5  includes various sensors, e.g., a temperature sensor, a humidity sensor, and an acceleration sensor, the browser management unit  22  acquires sensor information, which is output signals of the sensors, from the communication terminal  5  and outputs it to the browser  20 . 
     The transmission FIFO  24  is a buffer for storing therein video (audio) data [AEp] generated by the browser  20 . 
     The time management unit  25  manages time T, which is local to the distribution management apparatus  2 . The time acquisition unit  26  performs a time adjustment process in conjunction with a time control unit  56 , which is described later, of the communication terminal  5 . Specifically, the time acquisition unit  26  acquires time information (T) indicating the time T in the distribution management apparatus  2  from the time management unit  25 , receives time information (t) indicating time t in the communication terminal  5  from the time control unit  56 , which is described later, via the transceiving unit  31  and a transceiving unit  51 , and transmits the time information (t) and the time information (T) to the time control unit  56 . 
     The channel-adaptive-control unit  27  calculates, on the basis of transmission-delay-time information (D), playback delay time U, which is described later, and operating conditions including a frame rate and data resolution of a converting unit  10 , which is described later, of the encoder bridge unit  30 . The playback delay time U is time, for which playing back data is delayed by buffering the data until played back. Specifically, the channel-adaptive-control unit  27  changes operations of the encoder bridge unit  30  on the basis of the transmission-delay-time information (D) and a data size (e.g., the number of bits or the number of bytes). As will be described later, the transmission-delay-time information (D) indicates frequency distribution information formed from a plurality of pieces of transmission delay time D 1  acquired from a playback control unit  53  by a delay-information acquisition unit  57  of the communication terminal  5 . Each piece of the transmission delay time D 1  is time from when video (audio) data is transmitted from the distribution management apparatus  2  to when the same is received by the communication terminal  5 . 
     The encoder bridge unit  30  outputs frame data, each piece of which is generated by the browser  20  as still-picture (audio) data, to the converting unit  10 , which is described later, of the encoder bridge unit  30 . At this time, the converting unit  10  performs processes with the operating conditions calculated by the channel-adaptive-control unit  27  into consideration. 
     The encoder bridge unit  30  is described in more detail with reference to  FIG. 9  and  FIG. 10 .  FIG. 9  is a detailed diagram of the encoder bridge unit  30 .  FIG. 10  is a functional block diagram illustrating the functions of the converting unit  10 . 
     As illustrated in  FIG. 9 , the encoder bridge unit  30  includes a creation/selection/transfer unit  310 , a selection unit  320 , and a plurality of converting units  1   a ,  10   b , and  10   c  constructed therebetween. Although the three converting units  10   a ,  10   h , and  10   c  are illustrated herein, the number of the converting units may be any number. Hereinafter, an arbitrary one of the converting units is denoted as the converting unit  10 ″. 
     The converting unit  10  converts a data format of video (audio) data generated by the browser  20  into a data format that allows distribution to the communication terminal  5  via the communication network  9 . For this purpose, as illustrated in  FIG. 10 , the converting unit  10  includes a trimming unit  11 , a resizing unit  12 , a dividing unit  13 , and the encoding unit  19 . The trimming unit  11 , the resizing unit  12 , and the dividing unit  13  perform no process on audio data. 
     The trimming unit  11  performs a process of cutting out only a portion of a video. For example, when performing the above-described zoom-in display exploiting the multi-display, the trimming unit  11  cuts out a region to be displayed in a zoomed-in manner from video data generated by the browser  20 . When a whole video is to be displayed on one of the plurality of communication terminals  5 , while a partial region is to be displayed in a zoomed-in manner on another one(s) of the communication terminals  5 , the converting units  10  of the same number as the communication terminals  5  are provided in accordance with the above-described first operation data. In the converting unit  10 , which is one of the converting units  10 , assigned to the communication terminal  5  that displays the whole video, the process of the trimming unit  11  is not performed. By contrast, in the converting unit(s)  10  assigned to the communication terminal(s)  5  that displays the zoomed-in partial region, the trimming unit  11  cuts out a region at an initial position defined by selected coordinate information, which is described later, of a size defined by resolution information, which is described later, from the video data generated by the browser  20  in accordance with the above-described first operation data. 
     Further description by way of concrete example is given below. In the example illustrated in  FIG. 5 , in addition to the converting unit  10  being used, the converting unit  10  assigned to the communication terminal  5   f   2  and the converting unit  10  assigned to the communication terminal  5   f   3  are newly created in accordance with the first operation data fed from the communication terminal  5   f   1 . The converting unit  10  being used is assigned to the communication terminal  5   f   1 . The trimming unit  11  of the converting unit  10  assigned to the communication terminal  5   f   2  defines a size and an initial position of a region to be cut out on the basis of resolution information and selected coordinate information for the communication terminal  5   f   2  acquired from the terminal management apparatus  7  and cuts out the region from the video data generated by the browser  20 . Similarly, the trimming unit  11  of the converting unit  10  assigned to the communication terminal  5   f   3  defines a size and an initial position of a region to be cut out on the basis of resolution information and selected coordinate information for the communication terminal  5   f   3  acquired from the terminal management apparatus  7  and cuts out the region from the video data generated by the browser  20 . 
     When second operation data is transmitted from the communication terminal  5   f   1 , the trimming unit  11  of the converting unit  10  assigned to the communication terminal  5   f   2  changes the position of the region to be cut out, while maintaining its size, in accordance with the above-described distance and direction traveled by the guide frame indicated by the second operation data. Similarly, the trimming unit  11  of the converting unit  10  assigned to the communication terminal  5   f   2  changes the position of the region to be cut out, while maintaining its size, in accordance with the above-described distance and direction traveled by the guide frame indicated by the second operation data. The above-described zoom-in display exploiting the multi-display is achieved by this process, performed by the trimming unit  11 , of cutting out a video. 
     The resizing unit  12  changes a zoom ratio of a video (image). For example, in the example illustrated in  FIG. 5 , if the size of the video data generated by the browser  20  exceeds the display/playback capabilities (e.g., resolution) of the communication terminal  5   f   1 , the resizing unit  12  of the converting unit  10  assigned to the communication terminal  5   f   2  zooms out the video data generated by the browser  20  in accordance with the resolution of the communication terminal  5   f   1  to display the whole video on the communication terminal  5   f   1 . At this time, the size of the region to be cut out from the video data generated by the browser  20  by the trimming unit  11  of the converting unit  10  assigned to the communication terminal  5   f   2  or the converting unit  10  assigned to the communication terminal  5   f   3  can be set to a size that allows displaying the video that is not zoomed out by the resizing unit  12  on the communication terminal  5   f   2  or the communication terminal  5   f   3 , for example. At this time, the size of the region to be cut out from the video data generated by the browser  20  may preferably be a size that allows displaying, on the communication terminal  5   f   2  or the communication terminal  5   f   3 , the video data representing the region with the need of neither zooming out nor in by the resizing unit  12  (without processing by the resizing unit  12 ). Alternatively, the size of the region to be cut out from the video data generated by the browser  20  may be a size that allows displaying the video data representing the region zoomed in at a predetermined ratio by the resizing unit  12  on the communication terminal  5   f   2  or the communication terminal  5   f   3 . 
     The dividing unit  13  divides the web content acquired from the web server  8  as illustrated in  FIG. 4 . 
     The encoding unit  19  encodes image (audio) data generated by the browser  20 , thereby performing conversion into image (audio) data distributable to the communication terminal  5  via the communication network  9 . When the video is still (when no frame-to-frame alteration (change) occurs), the encoding unit  19  inserts skip frame (which may be referred to as “frame skip”) data to immediately before a motion occurs in the video, thereby saving band. When audio data is generated concurrently with still-picture data by rendering, the both data is encoded. When only audio data is generated, none of trimming, resizing, and dividing is performed but only encoding is performed to perform data compression. 
     The creation/selection/transfer unit  310  performs newly creating the converting unit  10 , selecting video (audio) data to be fed to the converting unit  10 , which is already created, and the like. Examples of a situation, in which the creation/selection/transfer unit  310  newly creates the converting unit  10 , include a situation, in which the creation/selection/transfer unit  310  creates the converting unit  10  capable of conversion depending on video (audio) data playback capabilities of the communication terminal  5  as in a case of performing the above-described zoom-in display exploiting the multi-display. Examples of a situation, in which the creation/selection/transfer unit  310  selects video (audio) data to be fed to the converting unit  10 , include a situation, in which the creation/selection/transfer unit  310  selects the converting unit  10  that is already created. For example, when starting distribution to the communication terminal  5   b  in addition distribution to the communication terminal  5   a , a scenario that the same video (audio) data as the video (audio) data being distributed to the communication terminal  5   a  is distributed to the communication terminal  5   b  can occur. The examples include a case where, in this scenario, the communication terminal  5   b  has the same video (audio) data playback capability as the playback capability of the communication terminal  5   a . Specifically, in such a case, the creation/selection/transfer unit  310  uses the converting unit  10   a , which is already created for the communication terminal  5   a , rather than newly creating the converting unit  10   b  for the communication terminal  5   b.    
     The selecting unit  320  selects a desired one from the converting units  10  that are already created. The selections made by the creation/selection/transfer unit  310  and the selection unit  320  enable performing distribution in various patterns. 
     Referring back to  FIG. 8 , the transceiving unit  31  transmits and receives various data, requests, and the like to and from the communication terminals  5 . For example, in a login process of the communication terminal  5 , the transceiving unit  31  transmits, to the transceiving unit  51 , which is described later, of the communication terminal  5 , authentication screen data for prompting a user to submit a login request. Furthermore, the transceiving unit  31  performs data transmission and data reception to and from application programs (user application and device application) installed on the communication terminal  5  via an HTTPS (Hypertext Transfer Protocol over Secure Socket Layer) server to receive a service(s) provided by the distribution system  1  using a protocol specific to the distribution system  1 . The protocol specific to the distribution system  1  is an HTTPS-based application layer protocol for uninterruptedly transmitting and receiving data in real time between the distribution management apparatus  2  and the communication terminal  5 . The transceiving unit  31  also performs processes including response transmission control, real-time data generation, client command transmission, response reception control, received data analysis, and gesture conversion. 
     The response transmission control is a process of managing an HTTPS session for downloading requested (requested) from the communication terminal  5  to transmit data from the distribution management apparatus  2  to the communication terminal  5 . Response of the HTTPS session for downloading does not end immediately but persists for a certain period of time (for one to several minutes). The transceiving unit  31  dynamically writes data to be transmitted to the communication terminal  5  to a body portion of the response. Furthermore, to save cost for reconnection, another request is desirably received from the communication terminal  5  before the preceding session ends. Even if connection is re-established, overhead can be cut by placing the transceiving unit  31  on standby until the preceding request is completed. 
     The real-time data generation is a process of adding a unique header to the compressed video (and compressed audio) data generated by the encoding unit  19  illustrated in  FIG. 10  and writing it to a body portion of HTTPS downlink to the communication terminal  5 . 
     The client command transmission is a process of generating command data to be transmitted to the communication terminal  5  and writing it to a body portion of HTTPS for distribution (downlink) to the communication terminal  5 . 
     The response reception control is a process of managing an HTTPS session for transmission (uplink) requested from the communication terminal  5  so that the distribution management apparatus  2  can receive data from the communication terminal  5 . Response of this HTTPS session does not end immediately but persists for a certain period of time (for one to several minutes). The communication terminal  5  dynamically writes data to be transmitted to the transceiving unit  31  of the distribution management apparatus  2  to a body portion of the request. 
     The received data analysis is a process of analyzing data transmitted from the communication terminal  5  on a per-type basis and passing the data to a necessary process. 
     The gesture conversion is a process of converting a gesture event entered by a user to the communication terminal  5   f  configured as the digital whiteboard with the electronic pen P or by handwriting into a form acceptable by the browser  20 . 
     Referring back to  FIG. 8 , the reception FIFO  34  is a buffer for storing therein video (audio) data decoded by the decoding unit  40 . 
     The recognition unit  35  performs processing on video (audio) data [E] received from the communication terminal  5 . Specifically, for example, the recognition unit  35  recognizes the face, age, sex, and the like of a person or an animal in a video captured by a camera  62 , which is described later, for signage purpose. Furthermore, the recognition unit  35  performs name tagging using face recognition, replacing a background video, and the like on a video captured by the camera  62 , which is described later, for office purpose. The recognition unit  35  stores recognition information indicating recognized matters in the storage unit  2000 . The recognition unit  35  achieves speedup by performing processing using a recognition expansion board. 
     The delay-information acquisition unit  37   a  is used in an uplink channel-adaptive-control process in connection with the delay-information acquisition unit  57  on the communication terminal  5  used in a downlink channel-adaptive-control process. Specifically, the delay-information acquisition unit  37   a  acquires transmission-delay-time information (d 1 ) indicating transmission delay time d 1  from the decoding unit  40 , holds it for a certain period of time, and when a plurality of pieces of the transmission-delay-time information (d 1 ) has been acquired, outputs transmission-delay-time information (d) indicating frequency distribution information formed from the plurality of pieces of transmission delay time d 1  to the channel-adaptive-control unit  37   b . The transmission-delay-time information (d 1 ) indicates time from when video (audio) data is transmitted from the communication terminal  5  to when the video (audio) data is received by the distribution management apparatus  2 . 
     The channel-adaptive-control unit  37   b  is used in the uplink channel-adaptive-control process in connection with the channel-adaptive-control unit  27  used in the downlink channel-adaptive-control process. Specifically, the channel-adaptive-control unit  37   b  calculates operating conditions of an encoding unit  60  on the communication terminal  5  on the basis of the transmission-delay-time information (d). Furthermore, the channel-adaptive-control unit  37   b  transmits a channel-adaptive-control signal indicating the operating conditions including a frame rate and data resolution to the encoding unit  60  of the communication terminal  5  via the transceiving unit  31  and the transceiving unit  51 , which is described later. 
     The decoding unit  40  decodes the video (audio) data [E] transmitted from the communication terminal  5 . Furthermore, the decoding unit  40  outputs the transmission-delay-time information (d 1 ) indicating the transmission delay time d 1  to the delay-information acquisition unit  37   a.    
     Functional Components of Communication Terminal 
     Functional components of the communication terminal  5  are described below with reference to  FIG. 11 .  FIG. 11  is a functional block diagram primarily illustrating functions of the communication terminal  5 . Although  FIG. 11  illustrates the communication terminal  5   f   1  as one of the communication terminal  5 , the communication terminals  5  other than the communication terminal  5   f   1  have similar functional components. Among the communication terminals  5 , the communication terminal  5 , on which the user application is installed, serves as an interface, across which a user performs login to the distribution system  1 , starting and stopping distribution of video (audio) data, and the like. By contrast, the communication terminal  5 , on which the device application is installed, does not has the above-described interface and performs only transmission and reception of video (audio) data and transmission of the operation data [p]. For convenience, the description below is made on an assumption that the user application is installed on the communication terminal  5 . 
     The communication terminal  5  implements the functional components illustrated in  FIG. 11  with hardware components similar to those illustrated in  FIG. 6  and a program (the user application). Specifically, the communication terminal  5  includes a decoding unit  50 , the transceiving unit  51 , an operating unit  52 , the playback control unit  53 , a rendering unit  55 , the time control unit  56 , the delay-information acquisition unit  57 , a display unit  58 , the encoding unit  60 , a terminal-information acquisition unit  510 , and a selected-coordinate generation unit  520 . The communication terminal  5  further includes a storage unit  5000  implemented by the RAM  203  illustrated in  FIG. 6 . The storage unit  5000  stores therein time difference information (Δ) indicating time difference Δ, which is described later, the time information (t) indicating the time t in the communication terminal  5 , terminal information acquired by the terminal-information acquisition unit  510 , which is described later, from the terminal management apparatus  7 , and the like. 
     The decoding unit  50  decodes the video (audio) data [AEp] distributed from the distribution management apparatus  2  and output from the playback control unit  53 . 
     The transceiving unit  51  transmits and receives various data, requests, and the like to and from the transceiving unit  31  of the distribution management apparatus  2  and to and from a transceiving unit  71   a , which is described later, of the terminal management apparatus  7 . For example, in the login process of the communication terminal  5 , the transceiving unit  51  submits a login request to the transceiving unit  71  of the terminal management apparatus  7  in response to startup, initiated by the operating unit  52 , of the communication terminal  5 . 
     The operating unit  52  performs a process of accepting an operation entered by a user. For example, the operating unit  52  accepts an input, selection, and the like made using a power-supply switch, a keyboard, a mouse, the electronic pen P, or the like, and transmits it as the operation data [p] to the browser management unit  22  of the distribution management apparatus  2 . 
     The playback control unit  53  buffers video (audio) data (real-time data packets) received from the transceiving unit  51  and outputs it to the decoding unit  50  with the playback delay time U taken into account. Furthermore, the playback control unit  53  calculates transmission-delay-time information (D 1 ) indicating the transmission delay time D 1  and outputs it to the delay-information acquisition unit  57 . 
     The rendering unit  55  renders the data decoded by the decoding unit  50 . 
     The time control unit  56  performs the time adjustment process in conjunction with the time acquisition unit  26  of the distribution management apparatus  2 . Specifically, the time control unit  56  acquires the time information (t) indicating the time t in the communication terminal  5  from the storage unit  5000 . Furthermore, the time control unit  56  submits a request for the time information (T) indicating the time T in the distribution management apparatus  2  to the time acquisition unit  26  of the distribution management apparatus  2  via the transceiving unit  51  and the transceiving unit  31 . At this time, the time information (t) is transmitted together with the request for the time information (T). 
     The delay-information acquisition unit  57  acquires the transmission-delay-time information (D 1 ) indicating the transmission delay time D 1  from the playback control unit  53 , holds it for a certain period of time, and when a plurality of pieces of the transmission-delay-time information (D 1 ) has been acquired, outputs the transmission-delay-time information (D) indicating frequency distribution information formed from the plurality of pieces of transmission delay time D 1  to the channel-adaptive-control unit  27  via the transceiving unit  51  and the transceiving unit  31 . The transmission-delay-time information (D) may be transmitted once for every 100 frames, for example. 
     The display unit  58  displays a video by playing back the data rendered by the rendering unit  55 . When an operation of zooming into a portion of the video being displayed is performed by a user using the operating unit  52 , the display unit  58  determines the size of the above-described guide frame on the basis of resolution information regarding the other communication terminal(s)  5  contained in the terminal information acquired by the terminal-information acquisition unit  510 , which is described later, from the terminal management apparatus  7  and stored in the storage unit  5000 . Furthermore, the display unit  58  determines the position where the above-described guide frame is to be displayed on the video being displayed on the basis of selected coordinate information (initial position) regarding the other communication terminal(s)  5  contained in the terminal information acquired by the terminal-information acquisition unit  510 , which is described later, from the terminal management apparatus  7  and stored in the storage unit  5000 . The display unit  58  displays the guide frame of the determined size by superimposing the guide frame at the determined position on the video being displayed. When an operation of moving the guide frame displayed superimposed on the video is performed by the user performs using the operating unit  52 , the display unit  58  causes the guide frame displayed superimposed on the image to move in accordance with the operation. 
     The encoding unit  60  transmits the video (audio) data [E], which is obtained by encoding data acquired from the built-in microphone  213  (see  FIG. 6 ), or the external camera  62  and an external microphone  63 , time information (t 0 ) indicating time t 0  at the current point in time in the communication terminal  5  acquired from the storage unit  5000 , and the time difference information (Δ), which is also acquired from the storage unit  5000 , indicating the time difference Δ to the decoding unit  40  of the distribution management apparatus  2  via the transceiving unit  51  and the transceiving unit  31 . The time difference is the difference between the time T managed locally in the distribution management apparatus  2  and the time t managed locally in the communication terminal  5 . The encoding unit  60  changes the operating conditions of the encoding unit  60  on the basis of the operating conditions indicated by the channel-adaptive-control signal received from the channel-adaptive-control unit  37   b . Furthermore, the encoding unit  60  transmits, in accordance with the changed new operating conditions, the video (audio) data [E], which is obtained by encoding the data acquired from the camera  62  and the microphone  63 , the time information (t 0 ) indicating the time t 0  at the current point in time in the communication terminal  5  acquired from the storage unit  5000 , and the time difference information (Δ) indicating the time difference Δ acquired from the storage unit  5000 , to the decoding unit  40  of the distribution management apparatus  2  via the transceiving unit  51  and the transceiving unit  31 . 
     The built-in microphone  213 , and the external camera  62  and the external microphone  63  are an example of input means and are various devices requiring encoding and decoding. The input means may be configured to be capable of outputting tactile (touch) data and olfactory (smell) data in addition to the video (audio) data.  FIG. 11  illustrates an example, in which the communication terminal  5   e  configured as the television conference terminal is connected to the communication terminal  5   f   1  configured as the digital whiteboard, and the camera and the microphone of the communication terminal  5   e  are used as the external camera  62  and the external microphone  63  of the communication terminal  5   f   1 . 
     The terminal-information acquisition unit  510  acquires, from the terminal management apparatus  7 , terminal information regarding the other communication terminals  5  managed by the terminal management apparatus  7  and stores it in the storage unit  5000 . The terminal information contains resolution information indicating resolution of the communication terminal  5  and selected coordinate information indicating the initial position where the guide frame is to be displayed as being superimposed. The method to be used by the terminal-information acquisition unit  510  in acquiring the terminal information from the terminal management apparatus  7  is not specifically limited but can be any method, with which the terminal information can be acquired without external leakage. 
     The selected-coordinate generation unit  520  generates coordinate information indicating a position where the display unit  58  is to display and superimpose the guide frame on the video being displayed in accordance with the operation of moving the guide frame performed by the user using the operating unit  52 . The display unit  58  displays and superimposes the guide frame on the video in accordance with the coordinate information generated by the selected-coordinate generation unit  520 , thereby moving the position of the guide frame in accordance with the user&#39;s operation. 
     Functional Components of Terminal Management Apparatus 
     Functional components of the terminal management apparatus  7  are described below with reference to  FIG. 12 .  FIG. 12  is a functional block diagram illustrating functions of the terminal management apparatus  7 . 
     The terminal management apparatus  7  implements the functional components illustrated in  FIG. 12  with hardware components similar to those illustrated in  FIG. 6  and a program. Specifically, the terminal management apparatus  7  includes the transceiving unit  71   a , a transceiving unit  71   b , and an authentication unit  75 . The terminal management apparatus  7  further includes a storage unit  7000  implemented by the HDD  204  illustrated in  FIG. 6 . 
     The transceiving unit  71   a  transmits and receives various data, requests, and the like to and from the communication terminal  5 . For example, the transceiving unit  71   a  receives a login request from the transceiving unit  51  of the communication terminal  5  and transmits a result of authentication on the login request to the transceiving unit  51 . The login request is a request requesting the distribution system  1  to authenticate the communication terminal  5 . The login request contains a terminal ID for unique identification of the communication terminal  5  and a user certificate. 
     The transceiving unit  71   b  transmits and receives various data, requests, and the like to and from the distribution management apparatus  2 . For example, the transceiving unit  71   b  receives a request for distribution-destination-selection-menu data  7030 , which is described later, from the transceiving unit  21  of the distribution management apparatus  2  and transmits the distribution-destination-selection-menu data  7030  to the transceiving unit  21 . 
     The authentication unit  75  searches through a terminal management table  7010  by the terminal ID and the user certificate contained in the login request received from the communication terminal  5  to determine whether or not the same combination of the terminal ID and the user certificate is contained, thereby authenticating the communication terminal  5 . 
     The storage unit  7000  stores therein the distribution-destination-selection-menu data  7030 , the terminal management table  7010 , and an available-terminal management table  7020 . 
     The distribution-destination-selection-menu data  7030  is data for displaying the distribution-destination selection menu screen illustrated in  FIG. 13 .  FIG. 13  is a conceptual diagram of the distribution-destination selection menu screen. A list of sharing IDs and display names, which are described later, regarding the communication terminals  5  that are selectable as distribution destination is displayed on the distribution-destination selection menu screen illustrated in  FIG. 13 . A user can distribute video (audio) data to a desired one of the communication terminals  5  by marking a checkbox of the communication terminal  5 , to which the user desires to distribute the video (audio) data, on the distribution-destination selection menu screen and pressing “OK” button. 
       FIG. 14  is a conceptual diagram of the terminal management table  7010 . As illustrated in  FIG. 14 , in the terminal management table  7010 , terminal IDs of the registered communication terminals  5 , user certificates, contract information about users&#39; usage of a service(s) provided by the distribution system  1 , terminal types of the communication terminals  5 , setting information indicating home URLs (Uniform Resource Locators) of the communication terminals  5 , execution environment information regarding the respective communication terminals  5 , sharing IDs, layout position information, and display name information that are mutually associated are managed. 
     The user certificate is a certificate certificating that the communication terminal  5  is permitted to connect to the distribution system  1 . The user certificate is given in advance to the communication terminals  5  permitted to connect to the distribution system  1 . The contract information indicates details of contract for usage of the service(s), which is provided by the distribution system  1 , by a user using the communication terminal  5  identified by the terminal ID. The terminal type indicates a type of the communication terminal  5 . The setting information indicates a home URL of the communication terminal  5  identified by the corresponding terminal ID. 
     The execution environment information includes “Favorite”, “Previous Cookie Information”, and “Cache File” of each of the communication terminals  5 . The execution environment information is transmitted to the distribution management apparatus  2  together with the setting information after login of each of the communication terminals  5  and used to provide the service(s) individually to the communication terminals  5 . 
     The sharing ID is an ID for use in remote sharing and the like performed, by each user, by causing the same video (audio) data as the video (audio) data being distributed to the own communication terminal  5  to the other communication terminal(s)  5  and is identification information for identification of the other communication terminal or a group of the other communication terminals. In the example illustrated in  FIG. 14 , the sharing ID assigned to the terminal ID “t006” is “v006”, the sharing ID assigned to the terminal ID “t007” is “v006”, and the sharing ID assigned to the terminal ID “t008” is “v006”. When a request for remote sharing with the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  assigned with the sharing ID “v006” is submitted from the communication terminal  5   a  assigned with the terminal ID “t001”, the distribution management apparatus  2  distributes, to the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3 , the same video (audio) data as the video (audio) data being distributed to the communication terminal  5   a . Note that, when the communication terminal Sa differs from the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  in resolution of the display unit  58 , the distribution management apparatus  2  distributes the video (audio) data accordingly. 
     The layout position information indicates, as illustrated in  FIG. 4  and  FIG. 5 , layout positions in a situation where the plurality of communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  are arranged in a row, for example. The display name information is information indicating the display names on the distribution-destination selection menu screen illustrated in  FIG. 13 . 
     The resolution information is information indicating resolution of each of the communication terminals  5 . Resolution is a measure indicating fineness of videos (images) handled by the display unit  58  included in the communication terminal  5  and is one of the display/playback capabilities of the communication terminal  5 . The resolution information indicates resolution of the communication terminal  5  by (the number of pixels in a row)×(the number of pixels in a column) as illustrated in  FIG. 16 , for example. 
     The selected coordinate information is information indicating an initial position where a guide frame associated with each of the communication terminals  5  is to be displayed superimposed on another one of the communication terminals  5 . For example, assume that, in the example illustrated in  FIG. 14 , the communication terminal  5  assigned with the terminal ID “t006” is the communication terminal  5   f   1  illustrated in  FIG. 5 ; the communication terminal  5  assigned with the terminal ID “t007” is the communication terminal  5   f   2  illustrated in  FIG. 5 ; the communication terminal  5  assigned with the terminal ID “t008” is the communication terminal  5   f   3  illustrated in  FIG. 5 . At this time, the selected coordinate information “(600100)” associated with the terminal ID “t007” indicates a start address of the guide frame, which is associated with the communication terminal  5   f   2 , to be displayed superimposed on a video being displayed on the communication terminal  5   f   1 . The selected coordinate information “(6002400)” associated with the terminal ID “t008” indicates a start address of the guide frame, which is associated with the communication terminal  5   f   3 , to be displayed superimposed on the video being displayed on the communication terminal  5   f   1 . The start address indicates an initial position of the guide frame and may be, for example, top-left coordinates of the guide frame. 
     When performing a zoom-in process exploiting the above-described multi-display, the communication terminal  5  that accepts user&#39;s zoom-in operation acquires terminal information containing resolution information and selected coordinate information from the terminal management apparatus  7 . For example, the above-described terminal-information acquisition unit  501  of the communication terminal  5  that accepts user&#39;s operation submits, to the terminal management apparatus  7 , a request for terminal information regarding the other communication terminal(s)  5  having the same sharing ID as the own communication terminal  5 . Responsive to the request from the communication terminal  5 , the terminal management apparatus  7  reads out resolution information and selected coordinate information regarding the communication terminal(s)  5  having the same sharing ID as the requesting communication terminal  5  from the terminal management table  7010  and transmits terminal information containing the resolution information and the selected coordinate information to the requesting communication terminal  5  as a response to the request. 
       FIG. 15  is a conceptual diagram of the available-terminal management table  7020 . In the available-terminal management table  7020 , the terminal IDs are managed such that each of the terminal IDs is associated with a sharing ID indicating another communication terminal or a group of other communication terminals, with which the communication terminal  5  indicated by the terminal ID can perform remote sharing. 
     Operations or Processes of Embodiment 
     Operations or processes of the present embodiment are described below with reference to  FIG. 16  to  FIG. 23 . 
     &lt;Basic Distribution Process&gt; 
     A concrete distribution process using a basic distribution method of the distribution management apparatus  2  is described first with reference to  FIG. 16 .  FIG. 16  is a sequence diagram illustrating a basic distribution process of the distribution management apparatus  2 . Although a scenario, in which a login request is submitted using the communication terminal  5   a , is described herein, a login may be performed using another one of the communication terminals  5  than the communication terminal  5   a.    
     As illustrated in  FIG. 16 , when a user turns on the power to the communication terminal  5   a , the transceiving unit  51  of the communication terminal  5   a  transmits a login request to the transceiving unit  71   a  of the terminal management apparatus  7  (Step S 21 ). It follows that the transceiving unit  71   a  of the terminal management apparatus  7  receives the login request and outputs it to the authentication unit  75 . This login request contains a terminal ID and a user certificate of the communication terminal  5   a . Hence, the authentication unit  75  acquires the terminal ID and the user certificate of the communication terminal  5   a.    
     Next, the authentication unit  75  searches through the terminal management table  7010  illustrated in  FIG. 14  by the terminal ID and the user certificate to determine whether or not the same combination of the terminal ID and the user certificate is contained, thereby authenticating the communication terminal  5   a  (Step S 22 ). The following description is made on an assumption that the terminal management table  7010  contains the same combination of the terminal ID and the user certificate or, in other words, the communication terminal  5   a  is authenticated as an authorized terminal in the distribution system  1 . 
     The transceiving unit  71   a  of the terminal management apparatus  7  transmits the IP address of the distribution management apparatus  2  to the transceiving unit  51   b  of the communication terminal  5   a  (Step S 23 ). The IP address of the distribution management apparatus  2  is acquired by the terminal management apparatus  7  from the distribution management apparatus  2  and stored in the storage unit  7000  in advance. 
     Next, the transceiving unit  71   b  of the terminal management apparatus  7  submits a request for starting the browser  20  to the transceiving unit  21  of the distribution management apparatus  2  (Step S 24 ). It follows that the transceiving unit  21  receives the request for starting the browser  20 . The browser management unit  22  starts the browser  20  in accordance with the startup request received by the transceiving unit  21  (Step S 25 ). 
     Next, the creation/selection/transfer unit  310  of the encoder bridge unit  30  creates the converting unit  10  in accordance with playback capability (e.g., resolution of a display) of the communication terminal  5   a  and a content type (Step S 26 ). 
     Next, the transceiving unit  21  submits a request for the content data [A] to the web server  8  as instructed by the browser  20  (Step S 27 ). In response thereto, the web server  8  reads out the requested content data [A] from a storage unit (not shown) of its own (Step S 28 ). The web server  8  transmits the content data [A] to the transceiving unit  21  of the distribution management apparatus  2  (Step S 29 ). 
     Next, the browser  20  renders the content data [A] received by the transceiving unit  21 , thereby generating frame data, each piece of which is still-picture (audio) data, and outputs it to the transmission FIFO  24  (Step S 30 ). The converting unit  10  performs conversion into the video (audio) data [A] to be distributed to the communication terminal  5   a  by encoding the frame data stored in the transmission FIFO  24  (Step S 31 ). 
     Next, the transceiving unit  31  transmits the video (audio) data [A] to the transceiving unit  51  of the communication terminal  5   a  (Step S 32 ). It follows that the transceiving unit  51  of the communication terminal  5   a  receives the video (audio) data [A] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   a , the decoding unit  50  acquires the video (audio) data [A] from the playback control unit  53  and decodes it (Step S 33 ). Thereafter, a speaker  61  plays back audio from the decoded audio data [A], while the display unit  58  plays back a video from the video data [A] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 34 ). 
     &lt;Time Adjustment Process&gt; 
     The time adjustment process is described below with reference to  FIG. 17 .  FIG. 17  is a sequence diagram illustrating the time adjustment process carried out between the distribution management apparatus  2  and the communication terminal  5 . 
     As illustrated in  FIG. 17 , first, the time control unit  56  of the communication terminal  5  acquires time information (t s ) in the communication terminal  5  from the storage unit  5000  to acquire time indicating a point in time when the transceiving unit  51  submits a request for the time information (T) to the distribution management apparatus  2  (Step S 81 ). The transceiving unit  51  submits the request for the time information (T) in the distribution management apparatus  2  to the transceiving unit  31  (Step S 82 ). At this time, the time information (t s ) is transmitted together with the request for the time information (T). 
     Next, the time acquisition unit  26  of the distribution management apparatus  2  acquires time information (T r ) in the distribution management apparatus  2  from the time management unit  25  to acquire time indicating a point in time when the transceiving unit  31  receives the request submitted at Step S 82  described above (Step S 83 ). Furthermore, the time acquisition unit  26  acquires time information (T s ) in the distribution management apparatus  2  from the time management unit  25  to acquire time indicating a point in time when the transceiving unit  31  responds to the request submitted at Step S 82  described above (Step S 84 ). The transceiving unit  31  transmits the time information (t s , T r , and T s ) to the transceiving unit  51  (Step S 85 ). 
     Next, the time control unit  56  of the communication terminal  5  acquires time information (t r ) in the communication terminal  5  from the storage unit  5000  to acquire time indicating a point in time when the transceiving unit  51  receives the response made at Step S 85  described above (Step S 86 ). The time control unit  56  of the communication terminal  5  calculates the time difference Δ between the distribution management apparatus  2  and the communication terminal  5  (Step S 87 ). The time difference Δ is expressed by the following Equation (1).
 
Δ=(( T   r   +T   s )/2)−(( t   r   +t   s )/2)  (1)
 
     The time control unit  56  stores the time difference information (Δ) indicating the time difference in the storage unit  5000  (Step S 88 ). This series of processing for time adjustment is performed regularly every minute, for example. 
     &lt;Downlink Channel-Adaptive-Control Process&gt; 
     A channel-adaptive-control process performed on (downlink) data transmitted from the distribution management apparatus  2  to the communication terminal  5  is described below with reference to  FIG. 18 .  FIG. 18  is a sequence diagram illustrating the channel-adaptive-control process performed on data transmitted from the distribution management apparatus  2  to the communication terminal  5 . 
     First, the channel-adaptive-control unit  27  of the distribution management apparatus  2  calculates playback-delay-time information (U) indicating the playback delay time U, for which the playback control unit  53  of the communication terminal  5  delays playing back video (audio) data by buffering it until played back, and outputs the playback-delay-time information (U) to the encoder bridge unit  30  (Step S 101 ). 
     Next, the transceiving unit  31  acquires the playback-delay-time information (U) from the encoder bridge unit  30  and transmits the playback-delay-time information (U) to the transceiving unit  51  of the communication terminal  5  (Step S 102 ). It follows that the transceiving unit  51  of the communication terminal  5  receives the playback-delay-time information (U). The encoder bridge unit  30  adds, to the video (audio) data [A] acquired from the transmission FIFO  24  and having undergone encoding and the like, time information (T 0 ) indicating time T 0  indicating a point in time when acquisition from the time management unit  25  is performed as a time stamp (Step S 103 ). The transceiving unit  31  transmits the video (audio) data and the time information (T 0 ) regarding the distribution management apparatus  2  to the transceiving unit  51  of the communication terminal  5  (Step S 104 ). It follows that the transceiving unit  51  of the communication terminal  5  receives the video (audio) data and the time information (T 0 ) regarding the distribution management apparatus  2  and outputs the video (audio) data and the time information (T 0 ) to the playback control unit  53 . 
     Next, in the communication terminal  5 , the playback control unit  53  waits until time in the communication terminal  5  reaches time (T 0 +U−Δ) using the playback-delay-time information (U) acquired at Step S 102  described above, the time information (T 0 ) acquired at Step S 104  described above, and the time difference information (Δ) stored in the storage unit  5000  at Step S 88  of  FIG. 17  and then outputs the video (audio) data to the decoding unit  50 , thereby causing the speaker  61  to play back audio and causing the display unit  58  to display a video through the rendering unit  55  (Step S 105 ). It follows that whereas only video (audio) data received by the communication terminal  5  in duration of the playback delay time U expressed by the following Expression (2) is played back, and video (audio) data not received in the duration is deleted without being played back because delay is too large.
 
 U ≧( t   0 +Δ)− T   0   (2)
 
     Furthermore, the playback control unit  53  reads out the time t 0  in the communication terminal  5  at the current point in time from the storage unit  5000  (Step S 106 ). The time t 0  indicates time in the communication terminal  5  at the point in time when the communication terminal  5  receives the video (audio) data from the distribution management apparatus  2 . Furthermore, the playback control unit  53  reads out, from the storage unit  5000 , the time difference information (Δ) indicating the time difference Δ stored at Step S 88  of  FIG. 17  (Step S 107 ). The playback control unit  53  calculates the transmission delay time D 1  indicating time from when the video (audio) data is transmitted from the distribution management apparatus  2  to when the video (audio) data is received by the communication terminal  5  (Step S 108 ). This calculation is performed using the following Equation (3). When the communication network  9  is congested, the transmission delay time D 1  is long.
 
 D 1=( t   0 +Δ)− T   0   (3)
 
     Next, the delay-information acquisition unit  57  acquires the transmission-delay-time information (D 1 ) indicating the transmission delay time D 1  from the playback control unit  53 , holds it for a certain period of time, and when a plurality of pieces of the transmission-delay-time information (D 1 ) has been acquired, outputs the transmission-delay-time information (D) indicating frequency distribution information formed from the plurality of pieces of transmission delay time D 1  to the transceiving unit  51  (Step S 109 ). The transceiving unit  51  transmits the transmission-delay-time information (D) to the transceiving unit  31  of the distribution management apparatus  2  (Step S 110 ). It follows that the transceiving unit  31  of the distribution management apparatus  2  receives the transmission-delay-time information (D) and outputs the transmission-delay-time information (D) to the channel-adaptive-control unit  27 . 
     Next, on the basis of the transmission-delay-time information (D), the channel-adaptive-control unit  27  of the distribution management apparatus  2  newly calculates playback delay time U′ and calculates the operating conditions including a frame rate and data resolution of the converting unit  10  and outputs them to the encoder bridge unit  30  (Step S 111 ). In other words, the channel-adaptive-control unit  27  changes operations of the encoder bridge unit  30  on the basis of the transmission-delay-time information (D) and a data size (e.g., the number of bits or the number of bytes). 
     Next, the transceiving unit  31  acquires playback-delay-time information (U′) indicating the new playback delay time U′ calculated at Step S 111  described above from the encoder bridge unit  30  and transmits the playback-delay-time information (U′) to the transceiving unit  51  of the communication terminal  5  (Step S 112 ). It follows that the transceiving unit  51  of the communication terminal  5  receives the playback-delay-time information (U′). 
     Furthermore, the converting unit  10  of the encoder bridge unit  30  changes the operating conditions of the converting unit  10  on the basis of the channel-adaptive-control signal indicating the operating conditions (Step S 113 ). For example, if, in a situation where the transmission delay time D 1  is excessively long, the playback delay time U is prolonged in accordance with the transmission delay time D 1 , time when the speaker  61  and the display unit  58  play back is excessively delayed. Hence, there is a limit to prolonging the playback delay time U. Under the circumstances, the channel-adaptive-control unit  27  copes with congestion of the communication network  9  by not only causing the encoder bridge unit  30  to change the playback delay time U to the playback delay time U′ but by also causing the converting unit  10  to decrease the frame rate of the video (audio) data or decrease the resolution of the video (audio) data. For this purpose, as at Step S 103  described above, the encoder bridge unit  30  adds the time information (T 0 ) indicating the current point in time to the video (audio) data [A] as a time stamp in accordance with the changed operating conditions (Step S 114 ). The transceiving unit  31  transmits the video (audio) data and the time information (T 0 ) regarding the distribution management apparatus  2  to the transceiving unit  51  of the communication terminal  5  (Step S 115 ). It follows that the transceiving unit  51  of the communication terminal  5  receives the video (audio) data and the time information (T 0 ) regarding the distribution management apparatus  2  and outputs the video (audio) data and the time information (T 0 ) to the playback control unit  53 . 
     Next, in the communication terminal  5 , the playback control unit  53  waits until time in the communication terminal  5  reaches time (T 0 +U′−Δ) using the playback-delay-time information (U′) acquired at Step S 112  described above, the time information (T 0 ) acquired at Step S 115  described above, and the time difference information (Δ) stored in the storage unit  5000  at Step S 88  of  FIG. 17  and then outputs the video (audio) data to the decoding unit  50 , thereby causing the speaker  61  to play back audio and causing the display unit  58  to display a video through the rendering unit  55  as at Step S 105  described above (Step S 116 ). This is followed by processing at Step S 106  and subsequent steps. The downlink channel-adaptive-control process is continuously performed in this manner. 
     &lt;Uplink Channel-Adaptive-Control Process&gt; 
     A channel-adaptive-control process performed on (uplink) data transmitted from the communication terminal  5  to the distribution management apparatus  2  is described below with reference to  FIG. 19 .  FIG. 19  is a sequence diagram illustrating the channel-adaptive-control process performed on data transmitted from the communication terminal  5  to the distribution management apparatus  2 . 
     First, the encoding unit  60  of the communication terminal  5  encodes content data input as video (audio) data [E] from the camera  62  and the microphone  63  (Step S 121 ). At this time, the encoding unit  60  acquires the time information (t 0 ) indicating the time t 0  at the current point in time in the communication terminal  5  and the time difference information (Δ) indicating the time difference from the storage unit  5000 , but the encoding unit  60  does not encode them. The transceiving unit  51  transmits the video (audio) data [E], the time information (t 0 ), and the time difference information (Δ) to the transceiving unit  31  of the distribution management apparatus  2  (Step S 122 ). It follows that the transceiving unit  31  of the distribution management apparatus  2  receives the video (audio) data [E], the time information (t 0 ), and the time difference information (Δ). 
     Next, in the distribution management apparatus  2 , the decoding unit  40  reads out, from the time management unit  25 , the time T 0  indicating a point in time when the video (audio) data [E] and the like is received at Step S 122  (Step S 123 ). The decoding unit  40  calculates the transmission delay time d 1  indicating time from when the video (audio) data is transmitted from the communication terminal  5  to when the video (audio) data is received by the distribution management apparatus  2  (Step S 124 ). This calculation is performed using the following Equation (4). When the communication network  9  is congested, the transmission delay time d 1  is long.
 
 d 1= T   0 −( t   0 +Δ)  (4)
 
     Next, as does the delay-information acquisition unit  57  of the communication terminal  5 , the delay-information acquisition unit  37   a  of the distribution management apparatus  2  acquires the transmission-delay-time information (d 1 ) indicating the transmission delay time d 1  from the decoding unit  40 , holds it for a certain period of time, and when a plurality of pieces of the transmission-delay-time information (d 1 ) has been acquired, outputs transmission-delay-time information (d) indicating frequency distribution information formed from the plurality of pieces of transmission delay time d 1  to the channel-adaptive-control unit  37   b  (Step S 125 ). 
     Next, the channel-adaptive-control unit  37   b  calculates the operating conditions of the encoding unit  60  of the communication terminal  5  on the basis of the transmission-delay-time information (d) (Step S 126 ). The transceiving unit  31  transmits a channel-adaptive-control signal indicating the operating conditions including a frame rate and data resolution to the transceiving unit  51  of the communication terminal  5  (Step S 127 ). It follows that the transceiving unit  51  of the communication terminal  5  receives the channel-adaptive-control signal. Thus, while, in the channel adaptive control (downlink) illustrated in  FIG. 18 , the channel-adaptive-control signal is output to the encoder bridge unit  30  within the same distribution management apparatus  2 , in the channel adaptive control (uplink) illustrated in  FIG. 19 , the channel-adaptive-control signal is transmitted from the distribution management apparatus  2  to the communication terminal  5  via the communication network  9 . 
     Next, the encoding unit  60  of the communication terminal  5  changes the operating conditions of the encoding unit  60  on the basis of the operating conditions indicated by the channel-adaptive-control signal received by the transceiving unit  51  (Step S 128 ). The encoding unit  60  performs processing similar to that performed as Step S 121  in accordance with the new operating conditions (Step S 129 ). The transceiving unit  51  transmits, as at Step S 122  described above, the video (audio) data [E], which is obtained by encoding data acquired from the camera  62  and the microphone  63 , the time information (t 0 ), which is acquired from the storage unit  5000 , indicating the time t 0  at the current point in time in the communication terminal  5 , and the time difference information (Δ), which is also acquired from the storage unit  5000 , indicating the time difference Δ to the transceiving unit  31  of the distribution management apparatus  2  (Step S 130 ). It follows that the transceiving unit  31  of the distribution management apparatus  2  receives the video (audio) data [E], the time information (t 0 ), and the time difference information (Δ). This is followed by processing at Step S 123  and subsequent steps. The uplink channel-adaptive-control process is continuously performed in this manner. 
     &lt;Multi-Display Process&gt; 
     A multi-display process is described below with reference to  FIG. 20  to  FIG. 22 .  FIG. 20  to  FIG. 22  are sequence diagrams illustrating the process for the multi-display illustrated in  FIG. 4 . An example, in which video (audio) data [XYZ] being played back on the communication terminal  5   a  is divided and played back also on the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3 , is described below. Herein, the browser  20  for displaying web content is denoted as “content browser  20   a ”; the browser  20  for displaying a setting screen for users is denoted as “setting browser  20   b ”. Processing corresponding to Step S 30  and subsequent steps is described below. 
     First, as illustrated in  FIG. 20 , the content browser  20   a  of the distribution management apparatus  2  renders the web content data [XYZ] acquired from the web server  8 , thereby generating frame data, each piece of which is still-picture (audio) data, and outputs it to the transmission FIFO  24  (Step S 201 ). The converting unit  10  of the encoder bridge unit  30  encodes the image (audio) data stored in the transmission FIFO  24 , thereby performing conversion into video (audio) data [XYZ] of a data format distributable to the communication terminal  5   a  (Step S 202 ). 
     Next, the transceiving unit  31  of the distribution management apparatus  2  transmits the video (audio) data [XYZ] converted by the converting unit  10  to the transceiving unit  51  of the communication terminal  5   a  (Step S 203 ). It follows that the transceiving unit  51  of the communication terminal  5   a  receives the video (audio) data [XYZ] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   a , the decoding unit  50  acquires the video (audio) data [XYZ] from the playback control unit  53  and decodes it (Step S 204 ). Thereafter, the speaker  61  plays back audio from the decoded audio data [XYZ], while the display unit  58  plays back a video from the video data [XYZ] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 205 ). 
     Next, a user of the communication terminal  5   a  switches a screen displayed on the display unit  58  to a menu request screen (not shown). The operating unit  52  accepts depression of a “distribution-destination selection menu” button (not shown) on the menu request screen (Step S 206 ). It follows that the transceiving unit  51  transmits a request for switching to the distribution-destination selection menu to the transceiving unit  71   a  of the terminal management apparatus  7  (Step S 207 ). It follows that the transceiving unit  71   a  of the terminal management apparatus  7  receives the request for switching to the distribution-destination selection menu. This request contains the terminal ID of the communication terminal  5   a.    
     Next, the transceiving unit  71   b  transmits a request for starting the setting browser  20   b  to the transceiving unit  21  of the distribution management apparatus  2  (Step S 208 ). It follows that the transceiving unit  21  of the distribution management apparatus  2  receives the request for starting the setting browser  20   b  and requests the browser management unit  22  to start up the setting browser  20   b.    
     Next, the browser management unit  22  starts up the setting browser  20   b  (Step S 209 ). The creation/selection/transfer unit  310  of the encoder bridge unit  30  performs switching such that output to the converting unit  10  (e.g., the converting unit  10   a ) taken from the content browser  20   a  is switched to output to the converting unit  10  (e.g., the converting unit  10   b ) taken from the setting browser  20   b  (Step S 210 ). In a case where the communication terminal  5   a  and another one (e.g., the communication terminal  5   b ) of the communication terminals  5  are receiving the video (audio) data at Step S 203  described above while sharing the converting unit  10  (e.g., the converting unit  10   a ), the creation/selection/transfer unit  310  of the encoder bridge unit  30  newly creates the converting unit  10  (e.g., the converting unit  10   b ) because the other communication terminal  5  (e.g., the communication terminal  5   b ) is using the converting unit  10  (e.g., the converting unit  10   a ) for the content browser  20   a.    
     The transceiving unit  21  transmits a request for the distribution-destination selection menu to the transceiving unit  71   b  of the terminal management apparatus  7  as instructed by the setting browser  20   b  (Step S 211 ). At this time, the terminal ID of the communication terminal  5   a  is also transmitted. It follows that the transceiving unit  71   b  of the terminal management apparatus  7  receives the request for the distribution-destination selection menu and outputs the terminal ID of the communication terminal  5   a  to the storage unit  7000 . 
     In response thereto, the storage unit  7000  of the terminal management apparatus  7  searches through the available-terminal management table  7020  by the terminal ID, thereby extracting a corresponding sharing ID(s) (Step S 212 ). The sharing ID indicates the communication terminal  5  that is usable by the communication terminal  5   a  in remote sharing. For example, when the terminal ID assigned to the communication terminal  5   a  is “t001”, sharing IDs “v003” and “v006” are extracted by searching through the available-terminal management table  7020  illustrated in  FIG. 15 . 
     Furthermore, the storage unit  7000  searches through the terminal management table  7010  by the extracted sharing ID, thereby extracting display name information indicating a corresponding display name(s) (Step S 213 ). In this example, as illustrated in  FIG. 14 , display names associated with the extracted sharing IDs “v003” and “v006” are respectively “Tokyo Head Office, 10F, MFP” and “Osaka Exhibition Room, 1F, Multi-Display”. 
     The transceiving unit  71   b  transmits, to the transceiving unit  21  of the distribution management apparatus  2 , distribution-destination-selection-menu data [M] as content data (Step S 214 ). It follows that the transceiving unit  21  of the distribution management apparatus  2  receives the distribution-destination-selection-menu data [M] and outputs it to the setting browser  20   b . The distribution-destination-selection-menu data [M] is information for causing the distribution-destination selection menu screen illustrated in  FIG. 13  to be displayed and contains checkboxes, sharing IDs, and display names. 
     Next, as illustrated in  FIG. 21 , the setting browser  20   b  renders the content data representing the distribution-destination-selection-menu data [M] acquired from the terminal management apparatus  7 , thereby generating frame data, each piece of which is still-picture (audio) data, and outputs it to the transmission FIFO  24  (Step S 221 ). The converting unit  10  of the encoder bridge unit  30  encodes the each piece of the frame data stored in the transmission FIFO  24 , thereby performing conversion into video (audio) data [M] of a data format distributable to the communication terminal  5   a  (Step S 222 ). 
     Next, the transceiving unit  31  transmits, to the transceiving unit  51  of the communication terminal  5   a , the video (audio) data [M] converted by the converting unit  10  (Step S 223 ). It follows that the transceiving unit  51  of the communication terminal  5   a  receives the video (audio) data [M] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   a , the decoding unit  50  acquires the video (audio) data [M] from the playback control unit  53  and decodes it (Step S 224 ). Thereafter, the display unit  58  plays back a video of the distribution-destination selection menu screen illustrated in  FIG. 13  from the video data [M] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 225 ). 
     Next, when a checkbox of the sharing ID “v006” is marked and the “OK” button is pressed by the user on the distribution-destination selection menu screen illustrated in  FIG. 13 , the operating unit  52  accepts the operation entered by the user (Step S 226 ). 
     Next, the transceiving unit  51  transmits a result of the marking as operation data [p] to the transceiving unit  31  of the distribution management apparatus  2  (Step S 227 ). It follows that the transceiving unit  31  of the distribution management apparatus  2  receives the marking result as the operation data [p] and outputs it to the setting browser  20   b.    
     Next, the setting browser  20   b  selects a sharing ID(s) on the basis of the marking result (Step S 228 ). The transceiving unit  21  transmits a distribution-destination addition request to the transceiving unit  71   b  of the terminal management apparatus  7  as instructed by the setting browser  20   b  (Step S 229 ). This distribution-destination addition request contains the sharing ID(s) selected at Step S 228 . It follows that the transceiving unit  71   b  of the terminal management apparatus  7  receives the distribution-destination addition request and outputs the sharing ID to the storage unit  7000 . The setting browser  20   b , which has completed its role, exits (Step S 230 ). Thereafter, the creation/selection/transfer unit  310  of the encoder bridge unit  30  performs switching such that output to the converting unit  10  taken from the setting browser  20   b  is returned to output to the converting unit  10  taken from the content browser  20   a  (Step S 231 ). 
     Next, as illustrated in  FIG. 22 , in the storage unit  7000  of the terminal management apparatus  7 , by searching through the terminal management table  7010  by the sharing ID transmitted at Step S 229 , an associated terminal ID(s) and associated layout position information are extracted (Step S 241 ). The transceiving unit  71   b  transmits a distribution-destination addition command to the transceiving unit  21  of the distribution management apparatus  2  (Step S 242 ). This distribution-destination addition command contains the terminal ID(s) and the layout position information extracted at Step S 241  described above. It follows that the transceiving unit  21  of the distribution management apparatus  2  receives the distribution-destination addition command and outputs the distribution-destination addition command to the browser management unit  22 . It is assumed herein that three pairs of the terminal ID and the layout position information, which are the terminal ID “t006” and the layout position information “left”, the terminal ID “t007” and the layout position information “middle”, and the terminal ID “t008” and the layout position information “right”, are contained. 
     Next, the creation/selection/transfer unit  310  of the encoder bridge unit  30  creates the converting unit  10  for the multi-display (Step S 243 ). At this time, the creation/selection/transfer unit  310  of the encoder bridge unit  30  acquires the terminal ID(s) and the layout position information from the browser management unit  22 . The dividing unit  13  of the converting unit  10  created at Step S 243  described above divides the frame data [XYZ], each piece of which is still-picture (audio) data, stored in the transmission FIFO  24 . The encoding unit  19  encodes each of the divided pieces of frame data (Step S 244 ). 
     The transceiving unit  31  transmits video (audio) data [X] encoded by the encoder bridge unit  30  to the transceiving unit  51  of the communication terminal  5   f   1  in accordance with the terminal ID (“t006”) and the layout position information (“left”) (Step S 245 _ 1 ). It follows that the transceiving unit  51  of the communication terminal  5   f   1  receives the video (audio) data [X] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   1 , the decoding unit  50  acquires the video (audio) data [X] from the playback control unit  53  and decodes it (Step S 246 _ 1 ). Thereafter, the speaker  61  plays back audio from the decoded audio data [X], while the display unit  58  plays back a video from the video data [X] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 247 _ 1 ). 
     Similarly, the transceiving unit  31  transmits video (audio) data [Y] encoded by the encoder bridge unit  30  to the transceiving unit  51  of the communication terminal  5   f   2  in accordance with the terminal ID (“t007”) and the layout position information (“middle”) (Step S 245 _ 2 ). It follows that the transceiving unit  51  of the communication terminal  5   f   2  receives the video (audio) data [Y] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   2 , the decoding unit  50  acquires the video (audio) data [Y] from the playback control unit  53  and decodes it (Step S 246 _ 2 ). Thereafter, the speaker  61  plays back audio from the decoded audio data [Y], while the display unit  58  plays back a video from the video data [Y] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 247 _ 2 ). 
     Further similarly, the transceiving unit  31  transmits video (audio) data [Z] encoded by the encoder bridge unit  30  to the transceiving unit  51  of the communication terminal  5   f   3  in accordance with the terminal ID (“t008”) and the layout position information (“right”) (Step S 245 _ 3 ). It follows that the transceiving unit  51  of the communication terminal  5   f   3  receives the video (audio) data [Z] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   3 , the decoding unit  50  acquires the video (audio) data [Z] from the playback control unit  53  and decodes it (Step S 246 _ 3 ). Thereafter, the speaker  61  plays back audio from the decoded audio data [Z], while the display unit  58  plays back a video from the video data [Z] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 247 _ 3 ). 
     &lt;Zoom-In Display Process Exploiting Multi-Display&gt; 
     A zoom-in display process exploiting the multi-display is described below with reference to  FIG. 23 .  FIG. 23  is a sequence diagram illustrating the zoom-in display process exploiting the multi-display illustrated in  FIG. 5 . Illustrated is an example in which, in a situation where the video [A] being played back on the communication terminal  5   f   1  is distributed to and played back also on the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3 , an operation, performed by a user, of zooming into and displaying a partial region of the video [A] being displayed on the communication terminal  5   f   1  is accepted, and videos [A′] and [A″] of the region are played back and displayed in a zoomed-in manner on the communication terminals  5   f   2  and  5   f   3 . A process similar to the multi-display process illustrated in  FIG. 20  to  FIG. 22  is performed also in this example. Description about processing similar to that in the multi-display process illustrated in  FIG. 20  to  FIG. 22  is omitted, and processing following Step S 247 _ 1 , Step S 247 _ 2 , and Step S 247 _ 3  of  FIG. 22  is described. Note that, in this example, the video data [A] is not divided but undergoes encoding and the like at Step S 244  of  FIG. 22 , and the video data [A] is transmitted to the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  at Step S 245 _ 1 , Step S 245 _ 2 , and Step S 245 _ 3 , respectively. The video data [A] is decoded by the decoding unit  50  of each of the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  at a corresponding one of Step S 246 _ 1 , Step S 246 _ 2 , and Step S 246 _ 3 . The video [A] is displayed on the display unit  58  of each of the communication terminals  5   f   1 ,  5   f   2 , and  5   f   3  at a corresponding one of Step S 247 _ 1 , Step S 247 _ 2 , and Step S 247 _ 3 . It is assumed that the communication terminal  5   f   1  acquires terminal information about the communication terminals  5   f   2  and  5   f   3  from the terminal management apparatus  7  and stores it in the storage unit  7000  in advance. The description below is made on an assumption that the terminal management table  7010  illustrated in  FIG. 14  is stored in the storage unit  7000 . 
     First, when an operation aimed at zooming into and displaying a portion of the video [A] displayed on the display unit  58  of the communication terminal  5   f   1  is performed by a user by using the operating unit  52  of the communication terminal  5   f   1 , this operation is accepted by the operating unit  52 . The transceiving unit  51  of the communication terminal  5   f   1  transmits first operation data indicating the operation of zooming into and displaying the portion of the video [A] to the transceiving unit  31  of the distribution management apparatus  2  (Step S 301 ). It follows that the transceiving unit  31  of the distribution management apparatus  2  receives the first operation data and outputs it to the browser management unit  22 . 
     Next, when the browser management unit  22  acquires the first operation data from the transceiving unit  31 , the transceiving unit  21  transmits, to the transceiving unit  71   b  of the terminal management apparatus  7 , a request for terminal information with designation by the terminal IDs of the communication terminals  5   f   2  and  5   f   3  (Step S 302 ). It follows that the transceiving unit  71   b  of the terminal management apparatus  7  receives the request for terminal information and outputs the terminal IDs of the communication terminals  5   f   2  and  5   f   3  to the storage unit  7000 . The storage unit  7000  reads out resolution information (1920*1080 and 1920*1080) and selected coordinate information ((600100) and (6002400)) associated with the terminal IDs of the communication terminals  5   f   2  and  5   f   3  by searching through the terminal management table  7010  by the terminal IDs of the communication terminals  5   f   2  and  5   f   3  (Step S 303 ). The transceiving unit  71   b  of the terminal management apparatus  7  transmits the terminal information (terminal-by-terminal terminal information regarding the communication terminals  5   f   2  and  5   f   3 ) containing the resolution information and the selected coordinate information read out from the terminal management table  7010  to the transceiving unit  21  of the distribution management apparatus  2  as a response to the request submitted at Step S 302  (Step S 304 ). It follows that the transceiving unit  21  of the distribution management apparatus  2  receives the terminal information (the terminal-by-terminal terminal information regarding the communication terminals  5   f   2  and  5   f   3 ) containing the resolution information and the selected coordinate information and outputs it to the browser management unit  22 . 
     Next, the converting unit  10  for the multi-display created at Step S 243  of  FIG. 22  acquires the resolution information and the selected coordinate information regarding the communication terminals  5   f   2  and  5   f   3  from the browser management unit  22  and performs trimming, resizing, encoding, and the like on each piece of the frame data [A] rendered by the browser  20  using the resolution information and the selected coordinate information regarding the communication terminals  5   f   2  and  5   f   3  (Step S 305 ). Specifically, in the converting unit  10  assigned to the communication terminal  5   f   2 , the trimming unit  11  cuts out a region [A′] of a size that depends on the resolution information regarding the communication terminal  5   f   2  from each piece of the frame data [A] rendered by the browser  20  in accordance with the selected coordinate information. Similarly, in the converting unit  10  assigned to the communication terminal  5   f   3 , the trimming unit  11  cuts out a region [A″] of a size that depends on the resolution information regarding the communication terminal  5   f   3  from each piece of the frame data [A] rendered by the browser  20  in accordance with the selected coordinate information. In each of the converting units  10 , the resizing unit  12  performs resizing and the like on each piece of the frame data [A], [A′], and [A″] as required depending on the resolution of the communication terminal  5 , and the encoding unit  19  encodes each piece of the frame data [A], [A′], and [A″]. 
     The transceiving unit  31  transmits the video data [A], on which the encoding and the like is performed by the converting unit  10  assigned to the communication terminal  5   f   1 , to the transceiving unit  51  of the communication terminal  5   f   1  (Step S 306 _ 1 ). It follows that the transceiving unit  51  of the communication terminal  5   f   1  receives the video data [A] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   1 , the decoding unit  50  acquires the video data [A] from the playback control unit  53  and decodes it (Step S 307 _ 1 ). Thereafter, the display unit  58  plays back the video [A] from the video data [A] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 308 _ 1 ). Hence, the display unit  58  of the communication terminal  5   f   1  continues displaying the video [A]. At this time, the display unit  58  of the communication terminal  5   f   1  displays guide frames indicating the regions to be zoomed in and displayed on the communication terminals  5   f   2  and  5   f   3  by superimposing the guide frames on the video [A] on the basis of the resolution information and the selected coordinate information contained in the terminal information regarding the communication terminals  5   f   2  and  5   f   3  acquired from the terminal management apparatus  7  and stored in the storage unit  5000  in advance. 
     The transceiving unit  31  of the distribution management apparatus  2  transmits the video data [A′], on which the encoding and the like is performed by the converting unit  10  assigned to the communication terminal  5   f   2 , to the transceiving unit  51  of the communication terminal  5   f   2  (Step S 306 _ 2 ). It follows that the transceiving unit  51  of the communication terminal  5   f   2  receives the video data [A′] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   2 , the decoding unit  50  acquires the video data [A′] from the playback control unit  53  and decodes it (Step S 307 _ 2 ). Thereafter, the display unit  58  plays back the video [A′] from the video data [A′] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 308 _ 2 ). Hence, the display unit  58  of the communication terminal  5   f   2  displays the zoomed-in video [A′] of the partial region (the region surrounded by the guide frame associated with the communication terminal  5   f   2 ) of the video [A] displayed on the display unit  58  of the communication terminal  5   f   1 . 
     Similarly, the transceiving unit  31  of the distribution management apparatus  2  transmits the video data [A″], on which the encoding and the like is performed by the converting unit  10  assigned to the communication terminal  5   f   3 , to the transceiving unit  51  of the communication terminal  5   f   3  (Step S 306 _ 3 ). It follows that the transceiving unit  51  of the communication terminal  5   f   3  receives the video data [A″] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   3 , the decoding unit  50  acquires the video data [A″] from the playback control unit  53  and decodes it (Step S 307 _ 3 ). Thereafter, the display unit  58  plays back the video [A″] from the video data [A″] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 308 _ 3 ). Hence, the display unit  58  of the communication terminal  5   f   3  displays the zoomed-in video [A″] of the partial region (the region surrounded by the guide frame associated with the communication terminal  5   f   3 ) of the video [A] displayed on the display unit  58  of the communication terminal  5   f   1 . 
     Next, when an operation of moving the guide frame (in this example, the guide frame associated with the communication terminal  5   f   2 ) on the video [A] displayed on the display unit  58  of the communication terminal  5   f   1  is performed by the user by using the operating unit  52  of the communication terminal  5   f   1 , this operation is accepted by the operating unit  52 . The transceiving unit  51  of the communication terminal  5   f   1  transmits second operation data containing a distance and direction traveled by the guide frame to the transceiving unit  31  of the distribution management apparatus  2  (Step S 309 ). It follows that the transceiving unit  31  of the distribution management apparatus  2  receives the second operation data and outputs it to the browser management unit  22 . 
     Next, when the browser management unit  22  receives the second operation data from the transceiving unit  31 , the converting unit  10  for the multi-display created at Step S 243  of  FIG. 22  acquires, from the browser management unit  22 , the distance and direction traveled by the guide frame indicated by the second operation data transmitted from the communication terminal  5   f   1 . The converting unit  10  for the multi-display performs trimming, resizing, encoding, and the like on each piece of the frame data [A] rendered by the browser  20  while changing the region to be cut out using the distance and direction traveled by the guide frame (Step S 310 ). Specifically, in a case where the guide frame moved by the user on the video [A] displayed on the display unit  58  of the communication terminal  5   f   1  is associated with the communication terminal  5   f   2 , the trimming unit  11  of the converting unit  10  assigned to the communication terminal  5   f   2  changes the position of the region [A′] to be cut out from each piece of the frame data [A] rendered by the browser  20  in accordance with the distance and direction traveled by the guide frame while maintaining its size. In each of the converting units  10 , the resizing unit  12  performs resizing and the like on each piece of the video data [A], [A′], and [A″] as required depending on the resolution of the communication terminal  5 , and the encoding unit  19  encodes each piece of the frame data [A], [A′], and [A″]. 
     The transceiving unit  31  transmits the video data [A], on which the encoding and the like performed by the converting unit  10  assigned to the communication terminal  5   f   1 , to the transceiving unit  51  of the communication terminal  5   f   1  (Step S 311 _ 1 ). It follows that the transceiving unit  51  of the communication terminal  5   f   1  receives the video data [A] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   1 , the decoding unit  50  acquires the video data [A] from the playback control unit  53  and decodes it (Step S 312 _ 1 ). Thereafter, the display unit  58  plays back the video [A] from the video data [A] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 313 _ 1 ). Hence, the display unit  58  of the communication terminal  5   f   1  continues displaying the video [A]. 
     The transceiving unit  31  of the distribution management apparatus  2  transmits the video data [A′], on which the encoding and the like is performed by the converting unit  10  assigned to the communication terminal  5   f   2 , to the transceiving unit  51  of the communication terminal  5   f   2  (Step S 311 _ 2 ). It follows that the transceiving unit  51  of the communication terminal  5   f   2  receives the video data [A′] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   2 , the decoding unit  50  acquires the video data [A′] from the playback control unit  53  and decodes it (Step S 312 _ 2 ). Thereafter, the display unit  58  plays back the video [A′] from the video data [A′] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 313 _ 2 ). Hence, the display unit  58  of the communication terminal  5   f   2  displays the zoomed-in video [A′] of the region surrounded by the guide frame having been moved in accordance with the user&#39;s operation on the video [A] displayed on the display unit  58  of the communication terminal  5   f   1 . 
     Similarly, the transceiving unit  31  of the distribution management apparatus  2  transmits the video data [A″], on which the encoding and the like is performed by the converting unit  10  assigned to the communication terminal  5   f   3 , to the transceiving unit  51  of the communication terminal  5   f   3  (Step S 311 _ 3 ). It follows that the transceiving unit  51  of the communication terminal  5   f   3  receives the video data [A″] and outputs it to the playback control unit  53 . 
     Next, in the communication terminal  5   f   3 , the decoding unit  50  acquires the video data [A″] from the playback control unit  53  and decodes it (Step S 312 _ 3 ). Thereafter, the display unit  58  plays back the video [A″] from the video data [A″] acquired from the decoding unit  50  and rendered by the rendering unit  55  (Step S 313 _ 3 ). Hence, the display unit  58  of the communication terminal  5   f   3  continues displaying the zoomed-in video [A″] of the partial region (the region surrounded by the guide frame associated with the communication terminal  5   f   3 ) of the video [A] displayed on the display unit  58  of the communication terminal  5   f   1 . 
     In the above-described example, the creation/selection/transfer unit  310  of the encoder bridge unit  30  creates the converting unit  10  for the multi-display before the user performs the operation of zooming into a portion of the video (before the first operation data is transmitted to the distribution management apparatus  2 ). Alternatively, a configuration, in which the converting unit  10  for the multi-display is created after the first operation data is transmitted to the distribution management apparatus  2 , may be employed. 
     Main Effects of Embodiment 
     As described above in detail by way of concrete examples, in the distribution system  1  of the present embodiment, the distribution management apparatus  2  on the cloud includes the browser  20  and the encoder bridge unit  30 , which performs encoding and the like. The browser  20  generates frame data by rendering content data described in a predetermined description language. The encoder bridge unit  30  performs encoding and the like on the frame data, thereby performing conversion into video (audio) data of a data format distributable to the communication terminal  5  via the communication network  9 . When first operation data indicating an operation of zooming into a partial region of a video being played back is received from one (a first communication terminal) of the plurality of communication terminals  5 , to which video data is distributed, the encoder bridge unit  30  cuts out a region, which is a partial region of the frame data rendered by the browser  20  and of which size depends on the display/playback capabilities (e.g., resolution) of another one (a second communication terminal) of the communication terminals  5 , converts frame data representing the cut-out region into video data, and distributes the video data to the second communication terminal. 
     Thus, in the distribution system  1  of the present embodiment, when an operation of zooming into a partial region of a whole video generated from content data is performed, the partial region is displayed on another one (the second communication terminal) of the communication terminals  5  than the communication terminal  5  (the first communication terminal) displaying the whole video in a fashion that depends on the display/playback capabilities of the other one of the communication terminals  5 . Therefore, it is possible to cause the communication terminals  5  to display a whole video of content and simultaneously to display a desired portion of the content in an easy-to-view manner. 
     Furthermore, in the distribution system  1  of the present embodiment, the communication terminal  5  (the first communication terminal) that displays the whole video displays a guide frame indicating the region to be zoomed in and displayed on the other one (the second communication terminal) of the communication terminals  5  by superimposing the guide frame on the video. The region to be zoomed in and displayed on the other one (the second communication terminal) of the communication terminals  5  is changed within the whole video in accordance with an operation performed on the guide frame. Thus, a user can specify a desired portion of content through intuitive operations, and therefore a high level of operability can be achieved. 
     MODIFICATIONS 
     In the distribution system  1  of the present embodiment, the terminal management apparatus  7  and the distribution management apparatus  2  are configured as separate apparatuses. Alternatively, the terminal management apparatus  7  and the distribution management apparatus  2  may be configured in a single apparatus by imparting the functions of the terminal management apparatus  7  to the distribution management apparatus  2 , for example. 
     The distribution management apparatus  2  and the terminal management apparatus  7  of the above embodiment may be implemented in a single computer or may be implemented in a plurality of computers by dividing the units (the functions, means, or the storage units) and allocating the units as desired to the computers. 
     Each of recording media, such as CD-ROMs, in which programs of the embodiment are stored, and the HDD  204 , in which the programs are stored, can be provided domestically or abroad as program products. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Laid-open Patent Application No. 2002-268969