Patent Publication Number: US-2007107039-A1

Title: Content presentation device communicating with another device through presented content

Description:
This nonprovisional application is based on Japanese Patent Applications Nos. 2005-325951 and 2006-262868 filed with the Japan Patent Office on Nov. 10, 2005 and Sep. 27, 2006, respectively, the entire contents of which are hereby incorporated by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a content presentation device, and particularly to a content presentation device communicating with another device through a presented content.  
      2. Description of the Background Art  
      As means for holding a conversation through a network having a plurality of apparatuses connected thereto, there is utilized voice transmission means, a typical example of which is a telephone. Additionally, as means for transmitting a video picture, an image, a character and others, there are utilized a television (TV) telephone and a video messenger such as a Windows (R) Messenger available from Microsoft Corporation. The Windows (R) Messenger provides means for transmitting a display of a personal computer application to a terminal on the other side to utilize the display for assisting conversation and offering an explanation. In the Windows (R) Messenger, a still image and a character are utilized to assist conversation.  
      In contrast, there have become popular in recent years an apparatus such as Hard Disk (HDD) recorder, with which many content data items of television broadcast programs are recorded to be viewed and listened at the time other than the broadcast time, and an apparatus with which a music Compact Disks (CDs) are stored in a home server within the scope of personal use so that one can enjoy listening music without exchanging the CDs. These apparatuses can be connected to an Ethernet (R) and a wireless Local Area Network (LAN), which makes it possible to obtain a list of contents from another apparatus through a home network at home, and replay a content. Furthermore, as a capacity of a storage device is increased, these apparatuses can store many broadcast contents and CD contents.  
      Under the circumstances, there have been proposed many functions of presenting information on a content. Japanese Patent Laying-Open No. 2004-118737 introduces a content in the context of communication. Japanese Patent Laying-Open No. 2004-173252 introduces a popular content supported by many people. Japanese Patent Laying-Open No. 2003-076704 presents viewers and listeners who tend to have similar interest. Japanese Patent Laying-Open No. 2003-087826 introduces viewers and listeners who tend to have similar interest. Japanese Patent Laying-Open No. 2003-223406 provides various functions of presenting information from a viewpoint of communication enhancement, such as a function of acquiring information on an interesting topic from user information (profile) and providing a subject matter that could be topical to both of the users, in the form of a world wide web (WEB) page.  
      As to these functions of presenting information in video communication, communication apparatuses cannot acquire content lists from recording apparatuses or music data storage devices in their own home networks, respectively, prior to the start of communication or during communication, exchange information with a particular apparatus on the other side, allow communicating persons to mutually recognize identical recorded content and tune existing on both sides of the persons, select the identical content, and replay the same simultaneously. When voice data and video data are transmitted from one side to the other side to replay the same content simultaneously, an amount of data to be transmitted must fall within a transmissible capacity of the network, and the copyrighted content must not be transmitted (delivered) to the third party without permission, from a viewpoint of copyright protection.  
      The situation in which both persons watch the same content and enjoy conversation by telephone, for example, is effective for them to enjoy a close family atmosphere at a living room, even if they are at remote locations. However, owing to limitations as described above, it is often difficult to enjoy such an atmosphere. Under the circumstances, it has been demanded by a user to provide a function capable of implementing an environment in which persons communicating with each other can browse or view and listen the same content and establish communication (conversation) with each other.  
     SUMMARY OF THE INVENTION  
      An object of the present invention is to provide a content presentation device capable of presenting the same (identical) content and allowing communication with a device on the other side.  
      In order to achieve the object above, according to a certain aspect of the present invention, a content presentation device includes a content storing unit storing contents and relevant information pieces relating to the contents, in a manner allowing the relevant information pieces to correspond to the contents, respectively, and an output unit. The content presentation device communicates with an external device. Here, the content presentation device communicating with the external device is referred to as a “first (one) content presentation device”, while the external device is referred to as a “second (the other) content presentation device”, which has a functional configuration similar to that of the first content presentation device. The first content presentation device includes: an information receiving unit receiving relevant information pieces read from a content storing unit in the second content presentation device and transmitted; a comparison unit comparing the relevant information pieces received by the information receiving unit and the relevant information pieces read from its own content storing unit, and outputting a comparison result; and a presentation unit. The presentation unit retrieves, from the content storing unit of the first content presentation device, based on the comparison result output from the comparison unit, a content identical to a content stored in a content storing unit in the second content presentation device and presents the content through the output unit.  
      Although the content storing unit is embedded in the content presentation device, it may be separate from the content presentation device. The content presentation device and the separate content storing unit are coupled by a signal transmitting unit such as the Ethernet (R) or the wireless local area network (LAN), in order that the content presentation device may access the content storing unit. An example of the content presentation device accessing the content storing unit through the signal transmitting unit includes, for example, a device accessible to the content storing unit through a home network according to a Digital Living Network Alliance (R) (DLNA (R)) or through a file sharing system, or a Video On Demand (VoD) device accessible to the subscribed content.  
      Accordingly, the content presentation device transmits the relevant information pieces stored in its own content storing unit to the other content presentation device and receives the relevant information pieces stored in the other content presentation device from the other content presentation device, compares the relevant information pieces received from the other device and the relevant information pieces owned by itself, and based on the comparison result, retrieves and presents a content identical to a content stored in the content storing unit of the other device. Accordingly, the content presentation devices can simultaneously present the identical content owned by them, even if the content presentation devices are separate from each other.  
      In this case, a content itself neither received nor transmitted between the content presentation devices, so that communication is possible without any regard of limitation on a transmission path (capacity or the like).  
      Furthermore, even if a content is copyrighted, the content is neither received nor transmitted between the content presentation devices, and hence copyright can be protected.  
      Preferably, the content presentation device is connected to a communication line. The content presentation device further includes a speech communication unit for holding conversation with a user of the second content presentation device through the communication line. Accordingly, the users of the content presentation devices can utilize their speech communication units to hold conversation with each other while they browse or view and listen the same content presented at their own output units, which allows them to enjoy a close family atmosphere at a living room, even if they are at remote locations.  
      Preferably, the comparison unit has a comparison and matching unit. The comparison and matching unit compares the relevant information pieces received by the information receiving unit and the relevant information pieces read from the content storing unit of the first content presentation device, and outputs a matching piece of the relevant information pieces, as a comparison result. Accordingly, the identical content can be specified if the relevant information pieces corresponding thereto match.  
      Preferably, the relevant information pieces include a comment on the content corresponding thereto. Accordingly, based on a result of comparison between the comments in the relevant information pieces, the identical content can be retrieved.  
      Preferably, the content presentation device further includes a unit communicating with an external information processing device storing information on the content, and based on the information on the content, which information is received from the information processing device, generating the relevant information pieces. The comparison unit has an update unit. The update unit updates the comment in the relevant information pieces received from the second content presentation device, by using the information on the content, which information is received from the information processing device, for comparison.  
      Accordingly, the update unit updates the comment in the relevant information pieces received from the second content presentation device, by using the information on the corresponding content, which information is received from the information processing device communicated by the first content presentation device. At that time, since the content presentation devices communicate with different information processing devices, there may be a case where comments in the relevant information pieces generated in the content presentation devices are different from each other, even if the comments are intended for the same content. Even in that case, the update unit can allow the comment to match with the comment in the relevant information pieces corresponding to the content in the content storing unit of the first content presentation device.  
      Accordingly, prior to the comparison between the relevant information pieces on the same content, the comments can be updated such that they match with each other. It is therefore possible to reliably retrieve the identical content, based on a result of comparison between the updated relevant information pieces.  
      Preferably, the relevant information pieces include a title or an elapsed time list of each of the contents corresponding thereto. When the contents corresponding thereto are a video picture, the elapsed time list shows a timing at which scenes are switched. When the contents corresponding thereto are a tune, the elapsed time list shows a time interval for which the tune continues or pauses.  
      Accordingly, it is possible to compare the titles of the contents in the relevant information pieces corresponding thereto, and based on a comparison result, retrieve the identical content. When the contents are a video picture, it is possible to retrieve the identical content, based on the result of comparison between the timings at which scenes of the video picture are switched. The detection of a scene change is a technique utilizing the fact that a motion vector is interrupted between adjacent frames of an image, and is a well-known technique used for generating a subhead in a program in a DVD recorder or the like. When the contents are a tune, it is possible to retrieve the identical content, based on the result of comparison between the time intervals for which the tune continues or pauses.  
      Preferably, the content presentation device further includes a presentation command generating unit generating a presentation command for instructing an operation for presenting the identical contents stored in both of the content presentation devices through the output unit, based on an external instruction, a presentation command transmitting unit transmitting the presentation command generated by the presentation command generating unit to the second content presentation device, and a presentation command receiving unit receiving a presentation command transmitted from the second content presentation device.  
      Furthermore, the presentation unit has a first presentation unit retrieving the identical content from the content storing unit and presenting the retrieved identical content through the output unit according to the instructed operation, based on the presentation command received by the presentation command receiving unit, and a second presentation unit retrieving the identical contents stored in both of the content presentation devices from the content storing unit and presenting the identical contents through the output unit according to the instructed operation, based on the presentation command generated by the presentation command generating unit.  
      Accordingly, when the presentation unit retrieves the identical content from the content storing units and presents the same, the presentation command is executed in the second presentation unit in the content presentation device generating the presentation command, and additionally, the presentation command is transmitted to the second content presentation device and executed in the first presentation unit in the second content presentation device. It is therefore possible to present the identical contents by means of the presentation units in both of the content presentation devices, by using the same presentation command and allowing the operations to be performed concurrently.  
      Accordingly, the identical contents stored in both of the content presentation devices are retrieved and presented while the operations instructed by the same presentation command are performed on the retrieved contents. It is therefore possible to replay the same scene of the content even if the content presentation devices are physically remote.  
      Preferably, the content presentation device further includes a response measurement unit measuring a response time required for transmitting the presentation command to the second content presentation device. When the presentation command transmitting unit transmits the presentation command to the second content presentation device, the second presentation unit modifies the operation, which is intended for the content and instructed by the presentation command, based on the response time measured by the response measurement unit.  
      Accordingly, when the presentation command is transmitted to the second content presentation device and then executed in the first presentation unit, the second presentation unit of the first content presentation device can, in anticipation of the response time required for the communication of the presentation command, modify the operation, which is intended for the content and instructed by the presentation command. Accordingly, the timings at which the content is operated (e.g. replay is started) can be brought in synchronization with each other between the content presentation devices.  
      Preferably, the content presentation device further includes a record command generating unit generating a record command for instructing an operation for recording a desired content in the content storing unit, based on an external instruction, a record command transmitting unit transmitting the record command generated by the record command generating unit to the second content presentation device, a record command receiving unit receiving a record command transmitted from a record command transmitting unit in the second content presentation device, and a unit performing an operation for storing the desired content in the content storing unit, based on the record command received by the record command receiving unit, and a unit performing an operation for storing the desired content in the content storing unit, based on the record command generated by the record command generating unit.  
      Accordingly, it is possible to concurrently store the identical contents in the content storing units in both of the content presentation devices, by using the same record command. It is therefore possible to store the identical contents in the content storage units in the contents presentation devices.  
      Preferably, the relevant information pieces received from the second content presentation device are discarded when a prescribed condition is established. It is therefore possible to clear a storage region for storing the received relevant information pieces whenever a prescribed condition is established, so that the storage region can effectively be utilized.  
      In order to achieve the above-described object, a content presentation method according to another aspect of the present invention, is a method using an information processing device including a storage unit storing contents and relevant information pieces relating to the contents, in a manner allowing the relevant information pieces to correspond to the contents, respectively, an output unit, and a communication unit. The method includes the steps of: receiving relevant information pieces read from a storage unit of the other information processing device and transmitted by a communication unit thereof; comparing the relevant information pieces received by the step of receiving and the relevant information pieces read from the storing unit of the one information processing device, and outputting a comparison result; and retrieving from the storage unit of the one information processing device, based on the comparison result output by the step of comparing, a content identical to a content stored in the other information processing device, and presenting the content through the output units.  
      In order to achieve the object above, a content presentation program according to still another aspect of the present invention is a program for executing the above-described method of presenting a content, by using a computer including a storage unit storing contents and relevant information pieces relating to the contents, in a manner allowing the relevant information pieces to correspond to the contents, respectively, an output unit, and a communication unit.  
      In order to achieve the object above, a machine-readable recording medium recording a content presentation program according to a further aspect of the present invention is a recording medium recording the above-described content presentation program for executing the content presentation method, by using a computer including a storing unit storing contents and relevant information pieces relating to the contents, in a manner allowing the relevant information pieces to correspond to the contents, respectively, an output unit, and a communication unit.  
      The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a configuration diagram of a system according to an embodiment.  
       FIGS. 2 and 3  are configuration diagrams of a computer according to the present embodiment.  
       FIGS. 4 and 5  are functional configuration diagrams of conversation devices according to the embodiment.  
       FIG. 6  is a flowchart of the entire process according to the embodiment.  
       FIGS. 7 and 8  are diagrams each showing a content list generated at each of the conversation devices in the embodiment.  
       FIG. 9  is a diagram showing a procedure for receiving and transmitting the content list according to the embodiment.  
       FIG. 10  is a flowchart showing that the content list is received and transmitted according to the embodiment.  
       FIGS. 11 and 12  are diagrams showing a comparison content list and an identical content list, respectively, according to the embodiment.  
       FIG. 13  is a process flowchart showing that the identical content list is generated according to the embodiment.  
       FIG. 14  is a process flowchart showing that scene change patterns are compared according to the embodiment.  
       FIG. 15  is a diagram showing that a content is selected from the identical content list according to the embodiment.  
       FIG. 16  is a diagram illustrating an identical viewing and listening command according to the embodiment.  
       FIG. 17  is a diagram showing a procedure for receiving and transmitting the identical viewing and listening command according to the embodiment.  
       FIG. 18  is a diagram showing a relationship among a program, a recording medium, and a device according to the embodiment.  
       FIG. 19  is a diagram showing how a desired content is selected from the displayed content list according to the embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The embodiment of the present invention will hereinafter be described in detail with reference to the drawings.  
      In the present embodiment, a user utilizes a conversation device mounted on each of plurality of computers connected through a communication line. The conversation device also functions as a content presentation device, so that the same content can be presented simultaneously even in the different conversation devices. Accordingly, the users can view and listen the same presented content and establish communication (conversation) with other users through the conversation devices.  
      In the present embodiment, a content storing unit is embedded in a content presentation device. However, it may be separate from the content presentation device. The content presentation device and the separate content storing unit are coupled by signal transmission means such as the Ethernet (R) or the wireless LAN, in order that the content presentation device may access the content storing unit. An example of the content presentation device accessing the content storing unit through the signal transmission means, includes a device accessible to the content storing unit through a home network according to a DLNA (R) or through a file sharing system, or a VoD device accessible to a subscribed content.  
      The content refers to information on video picture data (including still image data and moving image data), voice data, tune data, and the like. Presentation of the content refers to display of a video picture through a display, and output of a voice through a loudspeaker and the like.  
       FIG. 1  shows a schematic configuration of a communication system having a conversation device according to the present embodiment. Each of  FIGS. 2 and 3  shows a configuration of a computer having the conversation device according to the present embodiment mounted thereon.  FIG. 2  shows a block configuration of the computer, while  FIG. 3  shows an outward appearance of the computer. Although the conversation device is herein shown as a desktop type, it may be a portable type terminal.  
      Referring to  FIGS. 2 and 3 , the computer includes a display  610  formed of a cathode-ray tube (CRT), liquid crystals or the like, a speech communication unit  611  formed of a microphone, a loudspeaker or the like, an input unit  700  having a keyboard  650  and a mouse  660 , a CPU (a central processing unit)  622 , a memory  624  configured to include a Read Only Memory (ROM) or a Random Access Memory (RAM), a fixed disk  626  formed of an HDD, for example, an FD drive  630  accessing a flexible disk (FD)  632  detachably attached thereto, a Compact Disk Read Only Memory (CD-ROM) drive  640  accessing a CD-ROM  642  detachably attached thereto, a timer  670  for timing, a communication interface  680  for establishing a communication link between a communication network  300  and the computer, a television (TV) broadcast receiving unit  681 , a recording unit  682 , a replay unit  683 , and a printer  690 . Communication links are established among these units through a bus. The computer may be provided with a magnetic tape device accessing a cassette-type magnetic tape detachably attached thereto.  
      Communication network  300  is a wired or wireless (including an optical medium such as infrared ray) communication line, and includes an Internet.  
      Based on an instruction from CPU  622 , TV broadcast receiving unit  681  receives a TV broadcast signal on a specified channel, converts the signal into digital information such that the signal can be processed, and outputs the digital information. Recording unit  682  stores (records), in a prescribed region of fixed disk  626 , a TV broadcast program content received and output by TV broadcast receiving unit  681 , a content externally input through communication network  300 , or a content read from FD  632  and CD-ROM  642 .  
      Based on an instruction from CPU  622 , replay unit  683  reads the specified content from fixed disk  626  so as to replay the same. The read content is displayed through display  610 .  
      (Configuration)  
      Referring to  FIG. 1 , there are connected, in the system, first and second conversation devices  101  and  201  (hereinafter referred to as conversation devices  101  and  201 ) mounted on the computers as shown in  FIGS. 2 and 3 , first and second Electric Program Guide (EPG) managing site  302  and  304  (hereinafter referred to as EPG managing sites  302  and  304 ), each of which is a computer having a database, retrieving data stored in the database in response to a request, and transmitting (providing) the data to a requestor, and first and second CD Data Base (CDDB) managing sites  303  and  305  (hereinafter referred to as CDDB managing sites  303  and  305 ), through communication network  300 . Such devices communicate with each other through communication network  300 . Although two conversation devices are provided in the present embodiment, three or more conversation devices may be provided. Furthermore, although two EPG managing sites and two CDDB managing sites are provided, one or more EPG managing site(s) and one or more CDDB managing site(s) may be connected.  
      EPG managing sites  302  and  304  store data showing a broadcast channel, a program title, a broadcast date (including a time slot), a broadcast region, and a comment on the content of a TV program (content) broadcasted from a broadcast station, so that they read the data on the requested TV program and transmit the same to a requester.  
      CDDB managing sites  303  and  305  store data showing a title of a commercially-available CD (content) and a comment on a tune stored therein, so that they read the data on the requested CD and transmit the same to a requestor.  
      Conversation device  101  or conversation device  201  can access (communicate with) any of EPG managing sites  302  and  304 , and accessible to any of CDDB managing sites  303  and  305 . For convenience in explanation, however, assume that conversation device  101  accesses EPG managing site  302  and CDDB managing site  303 , while conversation device  201  accesses EPG managing site  304  and CDDB managing site  305 .  
      Conversation device  101  has a TV telephone  102  and a content storing unit  103 , while conversation device  201  has a TV telephone  202  and a content storing unit  203 . Each of TV telephones  102  and  202  includes a display  610  and a speech communication unit  611 , so that a user can hold conversation with another user through communication network  300  by means of speech communication unit  611 , and additionally, check the content presented (displayed) on display  610  or output (presented) as voice from a loudspeaker in speech communication unit  610 . The TV telephone is what is called a video phone.  
      Each of content storing units  103  and  203  corresponds to a prescribed region of fixed disk  626 , and can store at least one content. Here, content storing unit  103  stores a TV broadcast recorded content  1041 , which are information obtained by recording a TV broadcast program, and a CD content  1051 , which are information on a sound (a voice and a tune) downloaded from a prescribed site (not shown) providing a tune or transferred from a CD. Similarly, content storing unit  203  stores a TV broadcast recorded content  2041  and a CD content  2051 .  
      Although content storing units  103  and  203  are herein embedded in conversation devices  101  and  201 , respectively, they may be mounted to an external device connected to conversation devices  101  and  201  through communication network  300  or through dedicated, wired or wireless (including an optical communication path such as infrared ray) connection.  
      Each of content storing units  103  and  203  may be configured with a plurality of independent storage units, instead of being a single piece. In that case, the plurality of storage units are connected with each other via a communication function such as a network and form a single content storing unit.  
       FIGS. 4 and 5  show functional configurations of conversation devices  101  and  201 , respectively. Both devices have similar functional configurations. Conversation device  101  includes a first content list managing unit  107  (hereinafter referred to as content list managing unit  107 ), a first content managing unit  106  (hereinafter referred to as content managing unit  106 ), and first content storing unit  103  (hereinafter referred to as content storing unit  103 ). Content list managing unit  107  has a command generating unit  309  for generating an identical viewing and listening command CM, described below, for allowing the same operation to be performed in both of the conversation devices with regard to the selected content, a first network communication unit  310  (hereinafter referred to as network communication unit  310 ) for communicating with external units such as EPG managing site  302 , CDDB managing site  303 , and conversation device  201 , through communication network  300 , a first received content list storage unit  311  (hereinafter referred to as received content list storage unit  311 ) for storing a second content list  113  (hereinafter referred to as content list  113 ), a first comparison content list storage unit  312  (hereinafter referred to as comparison content list storage unit  312 ) for storing comparison content list  118 , a first content list comparison unit  313  (hereinafter referred to as content list comparison unit  313 ), a first content list storage unit  314  (hereinafter referred to as content list storage unit  314 ) for storing a first content list  112  (hereinafter referred to as content list  112 ), a first content list generating unit  315  (hereinafter referred to as content list generating unit  315 ), a first identical content list storage unit  316  (hereinafter referred to as identical content list storage unit  316 ) for storing an identical content list  119 , and a first identical content list display unit  317  (hereinafter referred to as identical content list display unit  317 ) for presenting (displaying) identical content list  119  on display  610 .  
      Content managing unit  106  has a first TV broadcast recorded content list  104  (hereinafter referred to as TV broadcast recorded content list  104 ) and a first CD content list  105  (hereinafter referred to as CD content list  105 ).  
      In the case where conversation device  101  is shared by a plurality of users, content managing unit  106  has TV broadcast recorded content list  104  and CD content list  105  which correspond to each of the users. When a user to utilize conversation device  101  is specified, TV broadcast recorded content list  104  and CD content list  105  corresponding to the user are uniquely determined. Accordingly, the following description can similarly be applied to such a case where a single conversation device is shared by a plurality of users.  
      Conversation device  201  includes a second content list managing unit  207  (hereinafter referred to as content list managing unit  207 ), a second content managing unit  206  (hereinafter referred to as content managing unit  206 ), and a second content storing unit  203  (hereinafter referred to as content storing unit  203 ). Content list managing unit  207  has a command generating unit  219  for generating identical viewing and listening command CM (i.e., a command for allowing users to view and listen the identical content), a second network communication unit  210  (hereinafter referred to as network communication unit  210 ) for communicating with external units such as EPG managing site  304 , CDDB managing site  305 , and conversation device  101  through communication network  300 , a second received content list storage unit  211  (hereinafter referred to as received content list storage unit  211 ) for storing first content list  112 , a second comparison content list storage unit  212  (hereinafter referred to as comparison content list storage unit  212 ) for storing a comparison content list  114 , a second content list comparison unit  213  (hereinafter referred to as content list comparison unit  213 ), a second content list storage unit  208  (hereinafter referred to as content list storage unit  208 ) for storing a second content list  113  (hereinafter referred to as content list  113 ), a second content list generating unit  209  (hereinafter referred to as content list generating unit  209 ), a second identical content list storage unit  216  (hereinafter referred to as identical content list storage unit  216 ) for storing an identical content list  115 , and a second identical content list display unit  217  (hereinafter referred to as identical content list display unit  217 ) for displaying identical content list  115  on display  610 .  
      Content managing unit  206  has a second TV broadcast recorded content list  204  (hereinafter referred to as TV broadcast recorded content list  204 ) and a second CD content list  205  (hereinafter referred to as CD content list  205 ).  
      Conversation devices  101  and  201  establish communication (conversation) therebetween through network communication units  310  and  210  corresponding to communication interface  680 , via communication network  300 .  
      TV broadcast recorded content  1041  and  2041  in content storing units  103  and  203 , respectively, are a TV program, for example, received by TV broadcast receiving unit  681  and recorded by recording unit  682 . TV broadcast recorded content lists  104  and  204  are generated in accordance with the information received from EPG managing sites  302  and  304  with regard to TV broadcast recorded content  1041  and  2041 , respectively. Furthermore, CD contents  1051  and  2051  in content storing units  103  and  203 , respectively, are data, for example, read from CD-ROM  642  and stored. CD content list  105  is generated in accordance with the information received from CDDB managing site  303  with regard to CD content  1051 , while CD content list  205  is generated in accordance with the information received from CDDB managing site  305  with regard to CD content  2051 .  
      Referring to the configurations in  FIGS. 4 and 5 , there is described a method of generating identical content lists  119  and  115  in accordance with the procedure in  FIG. 6 . Assume that conversation device  101  in  FIG. 4  is a device of a user A, while conversation device  201  is a device of a user B, and that users A and B establish communication (conversation) therebetween through conversation devices  101  and  201 . A program shown in each of the flowcharts described below including  FIG. 6 , is stored in advance in memory  624  of each of the conversation devices. CPU  622  reads the program from memory  624  and executes the same, so that the process according to each of the flowcharts is implemented.  
      Initially, content list generating unit  315  in conversation device  101  generates content list  112 , based on information in TV broadcast recorded content list  104  and CD content list  105  read from content managing unit  106  (step TA 1 ). Similarly, content list generating unit  209  in conversation device  201  generates content list  113 , based on information in TV broadcast recorded content list  204  and CD content list  205  read from content managing unit  206  (step TB 1 ). As described above, TV broadcast recorded content lists  104  and  204  are generated in accordance with the information from the different EPG managing sites, and CD content lists  105  and  205  are also generated in accordance with the information from different CDDB managing sites. Accordingly, even if content lists  112  and  113  include information on the same content, the information in content list  112  and the information in content list  113  may be different, even with regard to the same content.  
      The generated content lists  112  and  113  are stored in content list storage units  314  and  208 , respectively, and are read therefrom and transmitted to the other conversation devices through network communication units  310  and  210 , respectively, via communication network  300  (steps TA 3  and TB 3 ).  
      Examples of the generated content lists  112  and  113  are shown in  FIGS. 7 and 8 , respectively. Referring to  FIG. 7 , content list  112  has a record Ri (i=1, 2, 3 . . . ) corresponding to one content or has records Ri corresponding to a plurality of contents on one-to-one basis, and record Ri contains data in items T 1 -T 6 . Referring to  FIG. 8 , content list  113  has a record RCi (i=1, 2, 3 . . . ) corresponding to one content or has records RCi corresponding to a plurality of contents on one-to-one basis, and record RCi contains data in items T 1 -T 6 . Items T 1 -T 6  includes information which relates to the corresponding contents, and with which the corresponding contents can be specified.  
      It is possible in content lists  112  and  113  to determine whether or not records Ri and RCi are a record of a TV broadcast program content, based on whether or not records Ri and RCi have data in item T 3 , which data indicates a channel. Each of records Ri and RCi may contain data on a content type indicating that the information in the record is intended for a TV broadcast program, a tune in a CD and the like, or a movie in a DVD and the like. In that case, based on the type described above, it is possible to determine whether or not the record refers to a record of a TV broadcast program content.  
      The data in records R 1 , R 2  and R 3  in content list  112  refers to the content read from TV broadcast recorded content list  104 , while record R 4  refers to the content read from CD content list  105 . It is assumed herein that no information is registered in CD content list  205 . Accordingly, all the records RCi in content list  113  show the content read from TV broadcast recorded content list  204 .  
      Data in item T 1  shows a title of the corresponding content (a TV program, a tune or the like), data in item T 2  shows a broadcast date and a time slot of the corresponding content (the TV program), data in item T 3  shows a specified broadcast channel of the corresponding content (the TV program), data in item T 4  shows a specified region where the corresponding content (the TV program) is broadcasted, data in item T 5  shows information on a comment as to the content, which information is obtained from the EPG (or CDDB) of the corresponding content (a title of a tune, a performer, a musical performer, an introductory comment on a program, and the like), and data in item T 6  shows a series of times when a scene change occurs (or time intervals for which a tune continues or pauses (times between a tune)) in a list form (hereinafter referred to as an elapsed time list).  
      The scene change shown by the elapsed time list in item T 6  is a timing at which a display is switched, and the timing can easily be detected based on the fact that a motion vector of an image is interrupted between adjacent frames. This function of detecting the timing is generally embedded in a DVD recorder or the like, and is used for generating a header in recorded program content.  
      Although not shown, each of the records in content lists  112  and  113  stores data (an address) indicating a location where the corresponding content is stored. Accordingly, when the title of the content in item T 1  is specified, it is possible to search the corresponding record and read the address, and access (read) the content based on the read address.  
      In the case of TV broadcast recorded content in the present embodiment, at the time when recording is scheduled, information on the content to be recorded is stored in TV broadcast recorded content list  104  or  204 , and at the same time, content list  112  or  113  are generated based on the stored information in TV broadcast recorded content list  104  or  204 . The elapsed time list in item T 6  is generated by content managing unit  106  when an additional content is stored in content storing unit  103  in conversation device  101 , and stored in the corresponding record in TV broadcast recorded content list  104  or CD content list  105 . Similarly, the elapsed time list in item T 6  is generated in conversation device  201  by content managing unit  206  when an additional content is stored in content storing unit  203 , and stored in the corresponding record in TV broadcast recorded content list  204  or CD content list  205 .  
      It is also possible to store, in content storing unit  103  or  203 , a movie content downloaded from a prescribed site or transferred from a DVD. In that case, the content list of the movie content has a content similar to that of the lists of a music content. However, instead of the data on time intervals for which a tune continues or pauses, an elapsed time list for the scene change is shown in item T 6 .  
      When network communication unit  310  in conversation device  101  transmits content list  112  read from content list storage unit  314  to conversation device  201 , to which communication is established, network communication unit  210  in conversation device  201  receives content list  112  and stores the received content list  112  in received content list storage unit  211 . Similarly, network communication unit  210  in conversation device  201  transmits content list  113  read from content list storage unit  208  to conversation device  101 , to which communication is established, network communication unit  310  in conversation device  101  receives content list  113  and stores the received content list  113  in received content list storage unit  311 .  
      Content lists  112  and  113  are transferred under the information transmission procedure such as e-mail, a file transfer protocol (ftp), and a session initiation protocol (SIP). In this case, the content list may initially be encrypted and then transferred. When the content list is transferred by e-mail, content list  112  ( 113 ) is transmitted by being described in a mail text, or being attached to mail as a document, and is reproduced on the receiving end. When the content list is transferred by the ftp, content list  112  ( 113 ) is transferred in a file.  
      The transfer of content lists  112  and  113  by the SIP will be described with reference to  FIGS. 9 and 10 .  FIG. 9  schematically shows the flow (reception and transmission) of a signal between the conversation devices of user A and user B, whom user A holds conversation with.  FIG. 10  shows, on its left side, a flowchart of a process performed in conversation device  101  of user A, and shows, on its right side, a flowchart of a process performed in conversation device  201  of user B.  
      Initially, in step S 0501  in  FIG. 9 , based on an instruction from user A through keyboard  650 , for example, CPU  622  transmits a content list transfer request to conversation device  201  of user B through network communication unit  310  in conversation device  101  (step S 0303 ). At that time, network communication unit  310  searches an address book table or the like, not shown, stored in advance in memory  624 , for example, and obtains an address of conversation device  201  (step S 0302 ). The transfer request is therefore transmitted to the obtained address.  
      When network communication unit  210  in conversation device  201  receives the transfer request (step S 0401 ), it obtains an address of conversation device  101  (step S 0402 ). The address is obtained by, for example, reading an address of the transmitting end added to a header or the like of the received transfer request.  
      When the transfer request is received, CPU  622  in conversation device  201  outputs a message asking if user B permits transmission of the content list, through display  610  or a loudspeaker (not shown) in speech communication unit  611  (step S 0403 ). CPU  622  determines whether an instruction of transfer “OK” is input by the user through keyboard  650  or the like, within a certain time period after the message is output, which time period is measured by timer  670  (step S 0404 ). Assume that the data showing the certain time period is stored in advance in memory  624 . If it is determined that the instruction of “OK” is not input by the user within the certain time period (NO in step S 0404 ), a series of processes terminates, so that content list  113  in conversation device  201  is not transmitted to conversation device  101 .  
      In contrast, if user B inputs the instruction of OK within the certain time period (YES in step S 0404 ), CPU  622  reads content list  113  from content list storage unit  208  and provides the content list to network communication unit  210 , so that network communication unit  210  transmits the provided content list  113  to the address of conversation device  101  (steps S 0405  and S 0502 ).  
      CPU  622  in conversation device  101  determines whether or not content list  113  is received from network communication unit  210  in conversation device  201  within a certain time period after the transfer request is transmitted, which time period is measured by timer  670  (step S 0304 ). If the content list is not received within the certain time period (NO in step S 0304 ), a series of processes terminates. If the content list is received within the certain time period (YES in step S 0304 ), the received content list  113  is stored in received content list storage unit  311  (step S 0305 ). Content list  112  is then read from content list storage unit  314  and transmitted to conversation device  201  by network communication unit  310  (steps S 0306  and S 0503 ), and the process terminates.  
      Network communication unit  210  in conversation device  201  waits to receive the content list from conversation device  101  within a certain time period after network communication unit  210  transmits the content list to conversation device  101  (step S 0406 ). If network communication unit  210  cannot receive the content list within the certain time period (NO in step S 0407 ), a series of processes terminates. If network communication unit  210  receives the content list within the certain time period (YES in step S 0407 ), it stores the received content list  112  in received content list storage unit  211 , and the process terminates.  
      Returning to  FIG. 6 , in order to perform a process for generating an identical content list, which shows an identical content contained in both of the received content list and the self-made content list, in each of conversation devices  101  and  201  (processes in steps TA 5  and TB 5  described below), comparison content lists  118  and  114  are generated by content list comparison units  313  and  213  and stored in comparison content list storage units  312  and  212 , respectively, in steps TA 4  and TB 4 . In other words, the content list received from the other conversation device and the content list generated in its own conversation device are generated in accordance with the information from different EPG managing sites or different CDDB managing sites, and hence the information pieces, which show the content of a single TV broadcast program and are indicated by the data in item T 5  in the corresponding records Ri and RCi, may be different from each other, even with regard to the same content. Accordingly, the information pieces on the same TV broadcast program in item T 5  in records Ri and RCi are updated to match with each other, and thereby comparison content lists  118  and  114  are generated such that the content lists can be compared with each other.  
      In conversation device  201 , content list comparison unit  213  reads content list  112  from received content list storage unit  211 , and reads data on a broadcast date, a broadcast channel, and a broadcast region shown by items T 2 , T 3  and T 4 , respectively, with regard to each record Ri of a TV broadcast program content, so as to provide the data to network communication unit  210 . Network communication unit  210  communicates with EPG managing site  304 , and transmits a request for information on the content corresponding to the data provided by content list comparison unit  213 . When EPG managing site  304  receives the request, it searches the stored EPG information based on the data on a broadcast date, a broadcast channel, and a broadcast region, which data is received with the request, so that the EPG data on each of the corresponding contents (data on a title, a broadcast date, a broadcast channel, and a broadcast region of the contents, and a comment on the contents) is read therefrom and transmitted back to network communication unit  210 . Network communication unit  210  provides the received data to content list comparison unit  213 , so that content list comparison unit  213  generates comparison content list  114  based on the provided data, and stores the same in comparison content list storage unit  212 . A similar procedure is also carried out in conversation device  101 . Comparison content list  118  is generated by communication with EPG managing site  302  with the use of content list  113 , and stored in content list storage unit  312 .  
      Returning to  FIG. 6 , in steps TA 5  and TB 5 , the content of the comparison content list and the content of the self-made content list are compared, and based on a comparison result, identical content list is generated in each of the conversation devices.  
      In conversation device  101 , content list comparison unit  313  compares the information in content list  112  read from content list storage unit  314 , and the information in comparison content list  118  read from comparison content list storage unit  312 , and based on a comparison result, identical content list  119  is generated and stored in identical content list storage unit  316  (step TA 5 ). Similarly, in conversation device  201 , content list comparison unit  213  compares the information in content list  113  read from content list storage unit  208 , and the information in content list  114  read from comparison content list storage unit  212 , and based on a comparison result, identical content list  115  is generated and stored in identical content list storage unit  216  (step TB 5 ).  
      The process flowchart in steps TA 5  and TB 5  is shown in  FIG. 13 . The procedure in  FIG. 13  is carried out in both of conversation devices  101  and  201 , and hence explanation will be made taking conversation device  201  as an example. Assume that a list shown in  FIG. 11  refers to comparison content list  114 , and that identical content list  115  shown in  FIG. 12  is to be generated. Comparison content list  114  in  FIG. 11  has a record RDi containing data in items T 1 -T 6 , in a manner corresponding to the content.  
      A broadcast date and a comment as well as a broadcast channel in the EPG may vary depending on a broadcast region. Accordingly, content list  112  in  FIG. 7  and comparison content list  114  in  FIG. 11  are different in broadcast date, channel, and broadcast region.  
      Here, the elapsed time list shown by item T 6  in comparison content list  114  can be recorded as follows. For example, assume the case where the content is an image. In a top frame image in a scene, most blocks are not similar to the corresponding blocks in a frame just before the top frame image, and instead, similar to the corresponding blocks in a frame just after the top frame image. Three time-series frame images are extracted from a video picture, and similarities of all the corresponding blocks therein are calculated with the use of a color histogram to detect a scene change, and record a time period from the top to the time point at which the scene change occurs. Furthermore, in the case where the content corresponds to a music CD, a time length of a tune and a time length of a blank are recorded in the form of a digit string.  
      Referring to  FIG. 13 , content list comparison unit  213  initially reads content lists  113  and  114  from content list storage unit  208  and comparison content list storage unit  212 , respectively (steps S 0099  and S 0100 ), compares each record RCi of a TV broadcast program in the read content list  113  and the information in each record RDi of a TV broadcast program in comparison content list  114 , and generates identical content list  115  based on a comparison result.  
      Specifically, and initially, the first record RCi of a TV broadcast program in content list  113  is read (step S 0101 ), and the first record RDi in comparison content list  114  is read (step S 0102 ). Titles shown by data in item T 1  in the two read records RCi and RDi are compared (step S 0103 ). The titles are compared by the comparison between character strings in the titles. When character strings are compared, a character string “re” or “rebroadcast” in the title is excluded from a target of comparison.  
      After the titles are compared, if it is determined that the titles match (the character strings match) (YES in step S 0103 ), the record RCi is written to a region for identical content list  115  in memory  624  (step S 0107 ).  
      Subsequently, in order to determine whether the comparison should further be continued, it is determined whether all the records RDi are read from comparison content list  114 . If all the records RDi are completely read (YES in step S 0108 ), it is then determined whether all the records RCi are read from content list  113 . If all the records RCi are completely read (YES in step S 0109 ), the process for generating identical content list  115  terminates, so that the procedure returns to the processes in  FIG. 6 .  
      If it is determined that not all the records RDi are read from comparison content list  114  (NO in step S 0108 ), the procedure returns to step S 0102 , the next record RDi is read from comparison content list  114 , and the subsequent process is similarly performed. If it is determined that not all the records RCi are read from content list  113  (NO in step S 0109 ), the procedure returns to the process in step S 0101 , the next record RCi is read from content list  113 , and the subsequent process is similarly performed.  
      If it is determined that the titles (character strings) do not match (NO in step S 0103 ), content list comparison unit  313  compares character strings of an introduction and a comment of the program content, shown by the data in item T 5  in records RDi and RCi (step S 0104 ). If it is determined that the character strings match (YES in step S 0104 ), the process in step S 0107  and the following steps are similarly performed. If it is determined that the character strings do not match (NO in step S 0104 ), the procedure proceeds to the process in step S 0105  described below.  
      As a method of comparing character strings, steps S 0103  and S 0104  adopt a method of perfect matching between the character strings. As an example, however, if the character strings are divided into words, and at least 80% of noun words thereof match with each other, the character strings may be determined as “match”. For example, the character string in item T 5  in record RD 3  in comparison content list  114  do not completely match with the character string in item T 5  in record RC 3  in content list  113 . However, according to the condition in which at least 80% of the noun words should match with each other, both of the character strings are determined as “match”, and hence record RC 3  is stored in identical content list  115  in  FIG. 12 .  
      Such a criterion for determination may be modified in accordance with the EPG information registered in the EPG managing sites or the CDDB information registered in the CDDB managing sites.  
      In step S 0105 , the scene change elapsed times shown by the data in item T 6  in records RCi and RDi are compared according to the procedure in  FIG. 14 .  
      Referring to  FIG. 14 , there is initially counted the number of items of scene change data shown by times (minute. second) delimited by “,” in the scene change elapsed times shown by the data in item T 6  in each of records RCi and RDi (step S 0198 ). Assume that at least one item of scene change data is included in item T 6 . It is then determined whether or not the count values for both of the records match (step S 0199 ). If it is determined that they do not match (NO in step S 0199 ), a returned value is set to “N”, which indicates mismatch, in the process in step S 0211 , and the procedure returns to the former process.  
      If it is determined that the count values match (YES in step S 0199 ), a variable N is set to the count value (step S 0200 ), and a variable h, which controls the processes, is set to zero by default (step S 0201 ). Variable h serves as a variable for counting the number of scene change data items in item T 6 , and is sequentially count up by one in the processes. Accordingly, it is determined in step S 0202  whether or not the value of variable h reaches or exceeds the value of variable N. If it is determined that the value reaches or exceeds the value of variable N (YES in step S 0202 ), the procedure proceeds to the process in step S 0212 , and a returned value is set to “Y”, which indicates “match”, so that the procedure returns to the former process. In contrast, if it is determined that the value of variable h does not reach or exceed the value of variable N (NO in step S 0202 ), the value of variable h is incremented by one (step S 0203 ), so that the procedure proceeds to the process in step S 0204 .  
      In the following description, each scene change data item in item T 6  in record Ri is specified as A(h), while each scene change data item in item T 6  in record RDi is specified as B(h).  
      Next, scene change data A(h) and B(h) are retrieved (extracted) from records RCi and RDi, respectively (step S 0204 ). The times (minute. second) shown by the retrieved two scene change data items A(h) and B(h) are compared, and it is determined whether a difference between them is less than five seconds (step S 0210 ). If it is determined that the difference is less than five seconds (YES in step S 0210 ), the procedure proceeds to the process in step S 0202 . If it is determined that the difference is at least five seconds (NO in step S 0210 ), the procedure proceeds to the process in step S 0211 . Although the criterion for determination in step S 0210  is set to five seconds, the criterion is not limited thereto.  
      Here, detection is initially made in steps S 0198 , S 0199  and S 0202 , by using the number of scene change data items. However, the detection process may not be performed. In that case, it is determined in the processes in step S 0204  and step S 0206  whether or not the scene change data is successfully retrieved. In other words, in the case where the value of variable h reaches or exceeds two, if one of scene change data A(h) and B(h) can be retrieved and the other of scene change data A(h) and B(h) cannot be retrieved, the numbers of scene change data items in records RCi and RDi do not match, and hence the process in step S 0211  is performed. If both of the data items can be retrieved, the numbers of scene change data items in records RCi and RDi match (and determination as YES is obtained for all the scene change data in step S 0210 ), and hence the process in step S 0212  is performed.  
      Referring to the process in  FIG. 13 , when the scene change data comparison process in  FIG. 14  (step S 0105 ) terminates, it is determined in step S 0106  whether or not a result of the process in step S 0105  (returned value) indicates “Y” (match). If it is determined that the result indicates “Y” (YES in step S 0106 ), the processes in step S 0107  and the following steps are performed. If it is determined that the result does not indicate “Y”, in other words, indicates “N” (NO in step S 0106 ), record RCi is not written to identical content list  115 , and the processes in step S 0108  and the following steps are performed.  
      Identical content list  115  in  FIG. 12 , which is generated through the above-described procedure, is stored in identical content list storage unit  216 . If no record RCi is stored in identical content list  115 , an identical content list is not generated, which means that there are no identical contents stored in both of conversation devices  101  and  201 .  
      Similarly in conversation device  101 , according to the procedures described in  FIGS. 13 and 14 , content list comparison unit  313  generates identical content list  119  based on the information in content list  112  and the information in comparison content list  118 , and stores the generated identical content list  119  in identical content list storage unit  316 .  
      Returning to  FIG. 6 , CPU  622  next determines in steps TA 7  and TB 7  whether or not there are identical contents, namely, whether or not identical content lists  119  and  115  are generated. If it is determined that there are no identical contents, in other words, identical content lists could not be generated (NO in step TA 7 , and NO in step TB 7 ), a message indicating that there are no identical contents is output through display  610  or a loudspeaker in speech communication unit  611  (steps TA 13  and TB 13 ), and the process terminates.  
      In contrast, if it is determined that identical content list could be generated (YES in step TA 7 , and YES in step TB 7 ), identical content lists  119  and  115  are read by identical content list display units  317  and  217  from identical content list storage units  316  and  216 , respectively, and data based on the content of the read identical content lists is displayed on display  610  (steps TA 8  and TB 8 ). For example, it is desirable that at least a title and a comment in identical content list  115  in  FIG. 12  are displayed. This allows each of users A and B to check the information on the contents that can simultaneously be viewed and listened by the user himself/herself and the other user to hold conversation with.  
      In the case of a content downloaded through the Internet in communication network  300 , there is no information managing site. Accordingly, metadata attached to the content itself is utilized as a comment to be contained in the content list.  
      This is only an example of a method of generating identical content lists  115  and  119 . The type of feature quantity to be referred to with regard to the content (a time length of a tune, a time length of blank, temporal information of a scene change) may be modified. Information to be utilized may be added or deleted. A step in an algorithm may be added or omitted. A criterion for determination in each step may be modified.  
       FIG. 19  shows how the identical content list is displayed and the desired content is selected. After the identical content list in  FIG. 15  is displayed to one user and the other user as shown in  FIG. 19 , the users determine the content that would be a topic of their conversation. One of the users, such as user B, selects the information on one content in the displayed identical contents list  115 , by manipulating a remote controller  330  at hand and using a cursor  331 . Here, assume that user B of conversation device  201  selects the content indicated by cursor  331  in the displayed identical content list  115  in  FIG. 15  (step TB 9 ). Instead of user B, user A of conversation device  101  may select the content (step TA 9 ).  
      In order that both of the users can view and listen the same scene of the selected content at conversation device  101  and conversation device  201 , command generating unit  309  generates an identical viewing and listening command CM for replaying, at the same time instance, the same scene of the content selected by both of the users, based on an instruction input by user B through remote controller  331 , and provides the identical viewing and listening command CM to network communication unit  310 . Accordingly, network communication unit  310  transmits the provided identical viewing and listening command CM to conversation device  201  (step TB 11 ). Keyboard  650  may be used instead of remote controller  331  in  FIG. 19 . Furthermore, a preview display  332  (see  FIG. 19 ) of the selected content may be shown.  
      Identical view and listening command CM is a command for instructing an operation for similarly processing the selected content at both of the conversation devices, and there is used a type of identical viewing and listening command CM corresponding to the type of the operation.  
       FIG. 16  shows, for example, five types of identical viewing and listening command CM. Identical viewing and listening command CM for instructing replay, fast-forward, rewind (reverse and replay) of the content includes a command C 1  (replay: CPLAY, fast-forward: CFPLY, rewind: CRPLY) for instructing an operation to replay unit  683 , a content name C 2  for specifying the content to be replayed, and a start position C 3  showing a position of the content specified by content name C 2  from the top (an elapsed time from the start of recording), where the operation instructed by command C 1  is to be initiated.  
      Furthermore, identical viewing and listening command CM for scheduling recording of the content includes a command C 1  (CRECRSV) for instructing scheduling of recording, and content name C 2  for indicating the content to be recorded.  
      Furthermore, identical viewing and listening command CM for stopping an operation includes a command C 1  (CSTOP) for instructing a stop of an operation.  
      A character string code in identical viewing and listening command CM shown in  FIG. 16  is communicated with the use of an identical procedure determined in both of the devices, such as a session initiation protocol (SIP), in reliance on a general communication function such as the Internet, a wireless apparatus such as a mobile telephone, or infrared communication.  
      Assume that identical viewing and listening command CM is transmitted from conversation device  201  (step TB 11 ). Conversation device  101  on the other side receives the command through communication interface  680  (step TA 11 ). CPU  622  interprets the character string code in the received identical viewing and listening command CM, and based on a result of interpretation, controls recording unit  682  or replay unit  683 . Accordingly, recording unit  682  records, or schedules recording of, the TV broadcast program received through TV broadcast receiving unit  681 . Alternatively, replay unit  683  searches content list  112 , reads an address at which the content is stored, from a record corresponding to content name C 2  in identical viewing and listening command CM, retrieves (reads) the content from a region specified by the address in content storing unit  103 , so that the content is replayed in a mode according to command C 1 , from the position shown by start position C 3  (step TA 12 ).  
      Concurrently, similarly in conversation device  201 , CPU  622  interprets the generated identical viewing and listening command CM. Based on a result of interpretation, content list  113  is searched as in the case of conversation device  101 , and an address of the content specified by content name C 2  is read. The content is searched for and read at the address in content storing unit  203 , so that the content is replayed in a mode according to command C 1 , from the position shown by start position C 3  (step TB 12 ). Furthermore, recording unit  682  records, or schedules recording of, the TV broadcast program received through TV broadcast receiving unit  681 .  
      For example, assume that a character string “CPLAY NOSTALGIC TELEVISION 3.00” is set in identical viewing and listening command CM, and that this character string is transmitted from conversation device  201  of user B to conversation device  101  of user A in  FIG. 17 . Identical viewing and listening command CM instructs that the content having a title of “NOSTALGIC TELEVISION” should be replayed from a time point three minutes after the top of the content. In  FIG. 17 , identical viewing and listening command CM is shown as an “identical replay command”.  
      In  FIG. 17 , the identical replay command is initially transmitted from conversation device  201  of user B to conversation device  101  of user A, and at the same time, time measurement with the use of timer  670  is started in conversation device  201 . Conversation device  101  of user A receives the identical replay command and interprets the command to perform replay, and in addition, transmits “OK” back to conversation device  201  of user B. In conversation device  201  receiving “OK”, time measurement by timer  670  is completed, so that response time T 1 , which is time required for receiving the “OK” response from the time point when the identical replay command is transmitted, can be based on the time measured by timer  670 . CPU  622  in conversation device  201  of user B estimates (calculates), in anticipation of response time T 1 , that replay is started in conversation device  101  of user A, time T 2  (=T 1 ÷2) before the current time instance shown by timer  670 . Then CPU  622  itself modifies an operation to be performed to the content by replay unit  683 , which operation is instructed by the identical replay command, such that replay is started from a scene which appears time T 2  after the time point when three minutes have passed after the top of the same content. The method of determining time T 2  is modified according to the types of communication paths or the procedures of communication. Similarly, in other commands in identical viewing and listening command CM in  FIG. 16 , the time when the command is executed on the other side is estimated from response time T 1 , and based on a result of estimation, the operation to be performed to the content by identical viewing and listening command CM is modified, so that replay in its own device is controlled.  
      When the content to be recorded are selected, a character string “CRECRSV NOSTALGIC TELEVISION” is generated in identical viewing and listening command CM. The generated identical record scheduling command CM is transmitted and executed by recording unit  682 , so that scheduling for reliably recording the specified content is made.  
      Content list  112  and  113 , which are mutually exchanged and stored in the other conversation devices, the generated comparison content list  114 , and identical content list  115  are discarded when a prescribed condition is established, such as when conversation terminates, when a certain time period has passed, when the user issues an instruction, when the state set by the user is reached (e.g. the time instance specified by the user is reached), or when the same new list is generated (stored). In other words, they are deleted from the corresponding storage units.  
     Other Embodiments  
      The system having a process function described above is implemented by a program. In the present embodiment, the program is stored in a computer-readable recording medium.  
      Referring to  FIG. 18 , such a program  196  is stored in a storage unit  195  in conversation device  101 . Program  196  is read and executed by a processing unit  194  so that a prescribed operation is implemented in conversation device  101 .  
      Furthermore, program  196  is read from storing unit  195 , and moved or copied to a recording medium  192  by an external input/output control program (copy program)  193  that controls an external input/output unit  191 , so that program  196  can be stored in recording medium  192  as a program  197 . Furthermore, program  196  can be moved or copied as program  296  to a storing unit  295  in the other conversation device  201 , through an input/output program  293  of external input/output unit  291 , by utilizing recording medium  192 . Program  296  stored in conversation device  201  is read and executed by a processing unit  294 , so that a prescribed operation is implemented in conversation device  201 .  
      In the present embodiment, as to a recording medium of a program, a memory itself such as a ROM required for allowing a process to be performed at the computer shown in  FIG. 2 , which incorporates a conversation device, may serve as a program medium. Alternatively, a medium, which is readable by being inserted into a program reader such as a magnetic tape device or CD-ROM drive  640  provided as an external storing device, may serve as a program medium. For example, a medium may be a magnetic tape corresponding to storage medium  192 , or CD-ROM  642 . In any case, there may be used a scheme in which CPU  622  accesses and executes a program stored in the recording medium. Alternatively, in any case, there may be used a scheme in which a program is once read from a recording medium and the read program is loaded in a prescribed program storing area in the computer in  FIG. 2 , such as a program storing area of the RAM, and then the program is read from the program storing area and executed by CPU  622 . The program for loading is stored in advance in the computer.  
      Here, the program medium described above is a recording medium configured to be separable from the computer main body, and the program medium may be a medium carrying a fixed program. For example, such a recording medium includes a tape system such as a magnetic tape or a cassette tape, a disk system including a magnetic disk such as FD  632  or fixed disk (hard disk)  626 , or an optical disk such as CD-ROM  642 , a Magnetic Optical Disk (MO), a Mini Disk (MD), or a Digital Versatile Disk (DVD), a card system such as an IC card (including a memory card) or an optical card, or a semiconductor memory such as, for example, a Mask ROM, an Erasable and Programmable ROM (EPROM), an Electrically EPROM (EEPROM), or a flash ROM.  
      In the present embodiment, the computer adopts a configuration allowing itself to be connected to communication network  300  including the Internet, through communication interface  680 . Accordingly, the above-described program medium may be a medium carrying a program downloaded from communication network  300 . When a program is downloaded from communication network  300 , a program for downloading may be stored in advance in the computer main body, or may be installed in advance from another recording medium in the computer main body.  
      The content stored in the recording medium is not limited to a program, and data may be stored therein.  
      Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.