Abstract:
Digital media playback instruction distribution devices, methods, and programs access a memory storing content data, the content data including website content for distribution to a remote terminal, the website content including a display area for displaying digital media. The devices, methods, and programs receive a request for the stored web content from the remote terminal, calculate a time period over which a user of the remote terminal is estimated to need to browse the website content when it is rendered on the remote terminal, and transmit the website content and a delay instruction to the remote terminal, the delay instruction instructing the remote terminal to delay playback of digital media displayed in the display area until after the calculated time period has elapsed since display of the website content on the remote terminal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2013-195696 filed in Japan on Sep. 20, 2013. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a distribution device, a distribution method, and a non-transitory computer readable storage medium. 
     2. Description of the Related Art 
     Japanese Patent Application Laid-open No. 2011-128204 discloses an advertisement distribution device that causes a video to be played back on a display area for a video when a viewable area that is displayed on a screen of a web browser in an area of a content such as a web page includes a reference position set in the display area. 
     In the technique as disclosed in Japanese Patent Application Laid-open No. 2011-128204, for example, when the display area for displaying a video is present beside an article in the web page, the video is played back on the display area in some cases although a user such as a visitor of the web page has not finished reading the article, resulting in a problem. Thus, in the technique as disclosed in Japanese Patent Application Laid-open No. 2011-128204, it is still difficult to play back the video at an appropriate timing. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to at least partially solve the problems in the conventional technology. 
     Exemplary embodiments provide digital media playback instruction distribution devices, methods, and programs that access a memory storing content data, the content data including website content for distribution to a remote terminal, the website content including a display area for displaying digital media. The devices, methods, and programs receive a request for the stored web content from the remote terminal, calculate a time period over which a user of the remote terminal is estimated to need to browse the website content when it is rendered on the remote terminal, and transmit the website content and a delay instruction to the remote terminal, the delay instruction instructing the remote terminal to delay playback of digital media displayed in the display area until after the calculated time period has elapsed since display of the website content on the remote terminal. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a conceptual view for explaining an example of outline of processing according to a first embodiment; 
         FIG. 2  is a system configuration diagram illustrating an example of a distribution system in the first embodiment; 
         FIG. 3  is a view illustrating an example of a data structure that is stored in a content data storage unit; 
         FIG. 4  is a conceptual view illustrating an example of a content structure; 
         FIG. 5  is a view illustrating an example of a data structure that is stored in a video advertisement storage unit; 
         FIG. 6  is a block diagram illustrating an example of the functional configuration of a user terminal in the first embodiment; 
         FIG. 7  is a flowchart illustrating an example of operations of the user terminal in the first embodiment; 
         FIG. 8  is a block diagram illustrating an example of the functional configuration of a distribution device according to a second embodiment; 
         FIG. 9  is a view illustrating an example of a data structure that is stored in a user-by-user read time storage unit; 
         FIG. 10  is a view for explaining another processing that is executed by a read time calculation unit; 
         FIG. 11  is a view for explaining another processing that is executed by the read time calculation unit; 
         FIG. 12  is a view for explaining other pieces of processing that are executed by a determination unit and a video control unit; 
         FIG. 13  is a hardware configuration diagram illustrating an example of a computer that executes functions of a distribution device. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     The description begins with a first embodiment will be described with reference to the accompanying drawings. 
     Outline of Processing 
       FIG. 1  is a conceptual view for explaining an example of outline of processing in the first embodiment. 
     A user terminal acquires content data distributed from a distribution device and creates a content  100  based on the acquired content data. Then, the user terminal displays the created content  100  on a screen of the user terminal. The content  100  in the embodiment includes a display area  102  for a video and a video is displayed on the display area  102 . In the embodiment, the video that is played back in the display area  102  of the content  100  is a video advertisement, for example. 
     In the embodiment, the content data that is distributed to the user terminal from the distribution device includes a content control program. In the embodiment, the content  100  is a Web content, for example. The content control program is JavaScript (registered trademark), for example. The user terminal executes the content control program so as to control playback of the video advertisement in the display area  102 . The distribution device calculates a time T end  to the time at which a user is estimated to finish reading a document included in the content from the time at which the content based on the content data is displayed on the user terminal. Then, the distribution device adds the calculated time T end  to the content data that is distributed to the user terminal, and distributes the content data including the time T end  to the user terminal. 
     At a time T 1  in  FIG. 1 , the user terminal displays an area in the content  100  on the screen of the user terminal. At this stage, the video advertisement is not played back on the display area  102 . The user terminal acquires the time T end  included in the content data. 
     When an elapsed time since display of the content  100  started on the screen reaches the time T end , the user terminal causes the video advertisement to be played back on the display area  102  as in a state at a time T 2  in  FIG. 1 , for example. When the video advertisement is a video with sound, the user terminal causes the video to be played back in the display area  102  and causes the sound to be played back. 
     According to the embodiment, the video advertisement can be played back at a timing at which the user is estimated to finish reading the document included in the content. In other words, according to the embodiment, the video can be played back at an appropriate timing. 
     Configurations of Distribution System  10  and Distribution Device  20   
       FIG. 2  is a system configuration diagram illustrating an example of a distribution system in the first embodiment. A distribution system  10  in the embodiment includes a distribution device  20 , a user terminal  30 , and an advertising server  40 . The distribution device  20  and the advertising server  40  are connected to a communication circuit  11  and can transmit and receive communication data through the communication circuit  11 . 
     The distribution device  20  includes a content data storage unit  21 , a distribution unit  22 , and a read time calculation unit  23 .  FIG. 3  is a view illustrating an example of a data structure that is stored in the content data storage unit. As illustrated in  FIG. 3 , for example, the content data storage unit  21  stores therein pieces of content data  211  in association with URLs  210  indicating access destinations of the respective pieces of content data  211 .  FIG. 3  illustrates the content data storage unit  21  that stores therein the content data  211  of “content 1” in association with the URL  210  of “http://www.abcde.co.jp/xxx/” in a first record. 
     When the distribution unit  22  receives a URL transmitted from the user terminal  30 , it acquires, as content data (content data that is distributed to the user terminal  30 ) serving as a distribution target, the content data corresponding to the received URL from the content data storage unit  21 . Subsequently, the distribution unit  22  transmits the content data serving as the distribution target to the read time calculation unit  23 . When the distribution unit  22  receives a time T end , which will be described later, from the read time calculation unit  23 , it adds the received time T end  to the content data serving as the distribution target, and distributes the content data including the time T end  to the user terminal  30 . 
     The data structure of the content  100  in the embodiment is described.  FIG. 4  is a conceptual view illustrating an example of a content structure. The content  100  in the embodiment includes the display area  102  on which a video such as a video advertisement is played back and the display area  102  is associated with a video advertisement area ID indicating that it is an area for displaying the video advertisement. The content data includes information of the video advertisement area ID. In the following description, the video advertisement area ID is abbreviated to be referred to as an area ID in some cases. 
     The content  100  in the embodiment includes the time T end  calculated by the read time calculation unit  23 . For example, when the read time calculation unit  23  receives the content data serving as the distribution target from the distribution unit  22 , it counts the number of characters included in the received content data. The characters referred herein are characters from the head of the content based on the content data to the display area  102  on which the video is played back, for example. The read time calculation unit  23  calculates the time T end  to the time at which the user is estimated to finish reading the document included in the content from the time at which the content based on the content data is displayed on the user terminal  30  by multiplying the counted number of characters by a previously defined time a that is required for a user to read one character. Then, the read time calculation unit  23  transmits the calculated time T end  to the distribution unit  22 . The distribution unit  22  adds the received time Td to the content data that is distributed to the user terminal  30 , and distributes the content data including the time T end  to the user terminal  30 . 
     The advertising server  40  includes a video advertisement storage unit  43  and a provision unit  45 . 
       FIG. 5  is a view illustrating an example of a data structure that is stored in the video advertisement storage unit. As illustrated in  FIG. 5 , for example, the video advertisement storage unit  43  stores therein advertisement data tables for respective pieces of attribute information  430  each indicating an attribute of the user of the user terminal  30 . Each advertisement data table includes pieces of video advertisement data  432  and advertiser IDs  434  in association with advertisement IDs  431 . 
     The advertisement ID is information for identifying each advertisement. The attribute information includes age, sex, nationality, and the like of the user, for example. The attribute information may include information such as specification and performance of the user terminal  30  that is used by the user additionally. The advertiser ID is information for identifying an advertiser of each advertisement. In the following description, the video advertisement data is referred to as advertisement data simply in some cases. 
       FIG. 5  illustrates the advertisement data table that is associated with the attribute information  430  of “attribute 1”. The advertisement data table as illustrated in  FIG. 5  stores therein the video advertisement data  432  of “video advertisement 1” and the advertiser ID  433  of “S001” in association with the advertisement ID  431  of “A001”. 
     Description is continued with reference to  FIG. 2  again. When the provision unit  45  receives an advertising request having the attribute information of the user and equal to or more than one video advertisement area ID(s) from the user terminal  30  through the communication circuit  11 , it extracts the advertisement ID and the video advertisement data associated with the advertisement ID from the advertisement data table corresponding to the attribute information included in the received advertising request by referring to the video advertisement storage unit  43 . Then, the provision unit  45  transmits the advertisement ID and the video advertisement data to the user terminal  30  through the communication circuit  11  for each area ID included in the advertising request. 
     Configuration of User Terminal  30   
     The user terminal  30  is a mobile personal computer (PC), a personal digital assistant (PDA), a smart phone, or the like that is used by the user, and a browser application (for example, browser program) is installed on the user terminal  30 . In the embodiment, a standard browser program that is installed on the user terminal  30  interprets and executes the control program such as JavaScript. Various applications capable of displaying Web contents are installed on the smart device such as the smart phone in addition thereto in some cases. These applications may interpret and execute the control program such as JavaScript so as to cause the user terminal  30  to execute functions based on the control program.  FIG. 6  is a block diagram illustrating an example of the functional configuration of the user terminal in the first embodiment. The user terminal  30  in the embodiment includes a data acquisition unit  300 , a display control unit  301 , a determination unit  303 , a video control unit  305 , a display device  310 , an input device  311 , and a speaker  312 . 
     The browser program that is executed by an arithmetic device in the user terminal  30  causes the data acquisition unit  300 , the display control unit  301 , the determination unit  303 , and the video control unit  305  to function among the functions of the user terminal  30 . 
     In particular, the browser program executes the content control program that is included in the content data distributed from the distribution device  20  so as to cause the determination unit  303  and the video control unit  305  to function. 
     The data acquisition unit  300  transmits the URL of the content data to the distribution device  20  through the communication circuit  11  and acquires the content data from the distribution device  20  through the communication circuit  11 . Then, the data acquisition unit  300  analyzes the acquired content data so as to extract the area ID of the area included in the content  100  that is created. 
     Subsequently, the data acquisition unit  300  transmits an advertising request including the attribute information of the user of the distribution system  10  and the extracted area ID to the advertising server  40  through the communication circuit  11 . As the attribute information of the user, a HyperText Transfer Protocol cookie (HTTP cookie) that is stored in the user terminal  30  can be used. 
     Then, the data acquisition unit  300  receives pieces of information of the advertisement ID and the advertisement data for each area ID from the advertising server  40  through the communication circuit  11 . The data acquisition unit  300  transmits the content data to the display control unit  301 . 
     The display control unit  301  constructs the content  100  based on the content data received from the data acquisition unit  300 . The display control unit  301  extracts the time T end  included in the content data and transmits the extracted time T end  to the determination unit  303 . In addition, the display control unit  301  transmits a message indicating that display of the content  100  is started to the determination unit  303  at a timing at which the content  100  is displayed on the display device  310 . This enables the determination unit  303  to grasp the timing at which the display of the content  100  is started. 
     The display control unit  301  specifies a viewable area in the content  100  in accordance with an operation by the user that has been received through the input device  311  such as a touch panel. In the following description, an area that is displayed on the screen of the user terminal  30  in the area in the content  100  is referred to as a viewable area. The display control unit  301  transmits image data of the content  100  included in the specified viewable area to the display device  310 . When the display control unit  301  receives frame data of the played back video advertisement together with the area ID from the video control unit  305 , the display control unit  301  performs mapping of an image of the received frame data on the display area  102  corresponding to the received area ID and transmits it to the display device  310 . The display device  310  is a liquid crystal panel, for example, and displays an image based on the data received from the display control unit  301 . 
     The viewable area is described. The viewable area is an area included in the display area that is displayed by the browser program and included in the display area on the screen of the user terminal  30  in the area of the content  100 . The first embodiment is not limited thereto and, for example, an area included in the display area that is displayed by the browser program in the area of the content  100  may be set to the viewable area. 
     The display control unit  301  acquires positional information indicating the position and the size of the viewable area from an operating system (OS), for example. The display control unit  301  converts the positional information of the viewable area into coordinates in the content  100 , for example, and manages them. 
     The determination unit  303  repeatedly determines whether the time T end  has passed from the start of the display of the content  100  until it determines that the time T end  has passed while being triggered by transmission of the time T end  from the display control unit  301 . That is to say, the determination unit  303  repeatedly determines whether an estimated time required for the user operating the user terminal  30  to brows the document included in the content  100  has passed since display of the content  100  started. 
     When the determination unit  303  determines that the time T end  has passed from the start of the display of the content  100 , it receives the advertisement ID, the video advertisement data, and related information for each area ID from the display control unit  301 , and transmits the received area ID, and the advertisement ID, the video advertisement data, and the related information corresponding to the area ID to the video control unit  305 . When the video control unit  305  receives the area ID from the determination unit  303 , it starts playback of the video advertisement data corresponding to the received area ID. 
     For example, the video control unit  305  decodes the video advertisement data and transmits frame data together with the area ID to the display control unit  301  so as to start playback of the video advertisement. When the video advertisement is a video with sound, the video control unit  305  also decodes the sound and outputs the decoded sound through the speaker  312 . 
     Operations of User Terminal 
       FIG. 7  is a flowchart illustrating an example of operations of the user terminal in the first embodiment. The user terminal  30  acquires the content data from the distribution device  20  and reads the content control program included in the acquired content data so as to start operations as illustrated in the flowchart. 
     First, the determination unit  303  determines whether it has received the message indicating start of the display of the content  100  from the display control unit  301  (S 100 ). When the determination unit  303  has not received the message (No at S 100 ), the determination unit  303  performs the processing at S 100 , again. 
     On the other hand, when the determination unit  303  has received the message (Yes at S 100 ), the determination unit  303  activates a timer for measuring a time (S 102 ). This can measure a time from the start of the display of the content  100  by the timer. Then, the determination unit  303  determines whether a time indicated by the timer has reached the time T end  (S 104 ). When the time Ted has not passed (No at S 104 ), the determination unit  303  executes the processing at S 104 , again. On the other hand, when the time T end  has passed (Yes at S 104 ), the determination unit  303  transmits the area ID corresponding to the display area  102  included in the viewable area to the video control unit  305 . The video control unit  305  starts playback of the video advertisement data corresponding to the area ID received from the determination unit  303  (S 106 ). When the video control unit  305  has already played back a part of the video advertisement, it may play back the remaining video advertisement or may play back the video advertisement from the beginning again. 
     The first embodiment has been described above. 
     As described above, the distribution system  10  in the embodiment enables the video advertisement to be played back at the timing at which the user is estimated to finish reading the document included in the content. In other words, the distribution system  10  in the embodiment enables a video to be played back at an appropriate timing. 
     Furthermore, the distribution system  10  in the embodiment calculates the time T end  using the previously defined read time at per character, thereby controlling playback of the video with a simple method. 
     Second Embodiment 
     Next, a second embodiment is described with reference to the drawings. In the following description, the same reference numerals as those in the first embodiment denote the configurations having similar or the same functions as those in the first embodiment and description thereof is omitted in some cases. A distribution system in the second embodiment includes a distribution device  50  instead of the distribution device  20  in the first embodiment. 
     Configuration of Distribution Device  50   
       FIG. 8  is a block diagram illustrating an example of the functional configuration of the distribution device in the second embodiment. The distribution device  50  in the embodiment is different from the distribution device  20  in the above-mentioned first embodiment in that the distribution device  50  includes a read time calculation unit  53  instead of the read time calculation unit  23  and includes a user-by-user read time storage unit  54 . 
     In the distribution system in the embodiment, a time required for the user to read one character that is used for calculating the time T end  is different from that in the first embodiment. In the distribution system in the embodiment, the time Tea is calculated using a time required to read one character that corresponds to a user fox each user of the user terminal  30 . Thus, in the distribution system in the embodiment, the time T end  specific to the user is calculated, so that the timing at which the video advertisement is played back is a timing appropriate for the user. With this, the distribution system in the embodiment enables the video to be played back at a further appropriate timing. 
     In the embodiment, the user terminal  30  measures a time T close  until the user closes a screen for a content since the content is displayed on the screen of the user terminal  30 , and transmits the measured time, the URL corresponding to the content, and the user ID of the user of the user terminal  30  to the distribution device  50 . 
       FIG. 9  is a view illustrating an example of a data structure that is stored in the user-by-user read time storage unit. As illustrated in  FIG. 9 , the user-by-user read time storage unit  54  stores therein the read time per character in association with each user ID that is an ID of the user of the user terminal  30 . 
     A first record in the user-by-user read time storage unit  54  as illustrated in  FIG. 9  indicates that the read time per character for a user of which the user ID is “AAA” is 0.2 second. A second record indicates that the read time per character for a user of which the user ID is “BBB” is 0.15 second. 
     The read time calculation unit  53  calculates the read time per character for the user using the time T close , the URL corresponding to the content, and the user ID that have been received from the user terminal  30 , as will be described later. That is to say, first, the read time calculation unit  53  acquires content data corresponding to the received URL from the content data storage unit  21 . Next, the read time calculation unit  53  counts the number of characters that are included in the acquired content data. The read time calculation unit  53  calculates the read time per character for the user indicated by the received user ID by dividing the received time T close  by the counted number of characters. Thereafter, the read time calculation unit  53  stores the calculated read time and the user ID in the user-by-user read time storage unit  54  in an associated manner. In this manner, the read time calculation unit  53  stores the read time per character for the user in the user-by-user read time storage unit  54  in association with the user ID. 
     When the read time calculation unit  53  receives the content data serving as the distribution target from the distribution unit  22 , it counts the number of characters included in the received content data. The characters referred herein are characters from the head of the content based on the content data to the display area  102  on which the video is played back, for example. The read time calculation unit  53  acquires the read time corresponding to the user ID of the user terminal  30  serving as a target to which the content data is distributed from the user-by-user read time storage unit  54 . Then, the read time calculation unit  53  calculates a time T end  to the time at which the user is estimated to finish reading the document included in the content from the time at which the content based on the content data is displayed on the user terminal  30  by multiplying the counted number of characters by the acquired read time. Thereafter, the read time calculation unit  53  transmits the calculated time T end  to the distribution unit  22 . The distribution unit  22  adds the received time T end  to the content data that is distributed to the user terminal  30 , and distributes the content data including the time Tea to the user terminal  30 . 
     The second embodiment has been described above. 
     As described above, the distribution system in the embodiment calculates the time T end  using a time required to read one character that corresponds to a user for each user of the user terminal  30 . Thus, in the distribution system in the embodiment, the time T end  specific to the user is calculated, so that the timing at which the video advertisement is played back is a timing appropriate for the user. With this, the distribution system in the embodiment enables the video to be played back at a further appropriate timing. 
     When a thumbnail image is present in the content  100 , the user only views the thumbnail image without reading the document in the content  100  and shifts to a subsequent content in some cases. In this case, because the user has not read the document, playback of the video advertisement is preferably started immediately when the content  100  is displayed on the user terminal  30 . The read time calculation unit in the above-mentioned first embodiment and second embodiment can also determine whether a thumbnail image is present in the content  100  based on the content data serving as the distribution target. When the thumbnail image is present, the read time calculation unit can calculate the time T end  to be “0” second or a numerical value (for example, “0.1” second) close to 0. As illustrated in  FIG. 10 , when the content  100  including a thumbnail image  110  is displayed on the user terminal  30  at a time T 3 , a video advertisement is played back on the display area  102  at a time T 4  that is substantially the same as the time T 3 . Accordingly, the video can be played back at an appropriate timing for the user who views only the thumbnail image and shifts to the subsequent content when the thumbnail image is present in the content  100 . 
     When there are a plurality of articles in the content  100 , the user reads only an exclusive article among the articles and shifts to another content in some cases. In this case, when the content  100  is displayed on the user terminal  30 , the playback of the video advertisement is preferably started at a timing at which the user finishes reading the exclusive article. The read time calculation unit in the above-mentioned first embodiment and second embodiment can also determine whether there are a plurality of articles in the content  100  based on the content data serving as the distribution target. When there are the plurality of articles, the read time calculation unit can specify an article having the largest number of characters as the exclusive article and calculate the time T end  by multiplying the number of characters of the specified exclusive article by the read time per character. With this, as illustrated in  FIG. 11 , when the content  100  including a plurality of articles  100   a  to  100   e  is displayed on the user terminal  30  at a time T 5 , the video advertisement is played back on the display area  102  at a time T 6  at which the time T end  required for the user to browse the article  100   c  having the largest number of characters and considered to be the exclusive article has passed from the time T 5 . Accordingly, the video can be played back at an appropriate timing for the user who reads only the exclusive article and shifts to another content. 
     The determination unit  303  and the video control unit  305  in the first embodiment and the second embodiment can perform various pieces of processing in addition to the above-mentioned pieces of processing. The content  100  is a content that is displayed in a timeline format and reload of the content  100  is started with an operation by the user in some cases. The start of the reload indicates that the user has browsed previous matters of the content highly possibly. When the video advertisement is played back on a subsequent portion on the reloaded content, there is a high possibility that the user will view the video advertisement. Based on this, the determination unit  303  determines whether the subsequent matters of the content have been reloaded. When it is determined that the subsequent matters of the content have been reloaded, the video control unit  305  starts playback of the video advertisement on a predetermined portion (for example, head portion) of the reloaded subsequent matters of the content. This enables the user terminal  30  to play back the video advertisement under a condition where the user views the video advertisement highly possibly. 
     For example, a button  103  for receiving a request to reload the subsequent matters of the content  100  is displayed on the user terminal  30  at a time T 7  in  FIG. 12 . When the user touches the button  103  and the user terminal  30  receives the request to reload the subsequent matters of the content  100  from the user at a subsequent time T 8 , the subsequent matters of the content  100  are reloaded. In this case, the determination unit  303  determines that the subsequent matters of the content have been reloaded. Thereafter, the video control unit  305  starts playback of the video advertisement on the predetermined portion (for example, head portion) of the reloaded subsequent matters of the content at a time T 9  in  FIG. 12 . This enables the user terminal  30  to play back the video advertisement under a condition where the user views the video advertisement highly possibly. 
     Furthermore, in the first embodiment and the second embodiment, the read time calculation unit of the distribution device counts the number of characters from the head of the content to the display area  102  on which the video is played back and calculates the time To by multiplying the counted number of characters by the read time per character. Alternatively, the read time calculation unit of the distribution device may count the number of characters from the head of the content to a predetermined line, and calculate the time T end  by multiplying the counted number of characters by the read time per character by the method same as that in the first embodiment and the second embodiment. With this, when the display area  102  is included in the viewable area after the user reads the content displayed on the user terminal  30  by the first predetermined number of lines and scrolls the content displayed on the user terminal  30 , the video can be played back at a timing at which the display area  102  is included in the viewable area. Accordingly, the video can be played back at an appropriate timing. 
     Furthermore, the read time calculation unit of the distribution device can also count the number of characters from the head of the content to the end of the content, and calculate the time T end  by multiplying the counted number of characters by the read time per character by the method same as that in the first embodiment and the second embodiment. With this, the video can be played back at a timing at which the user has read all the characters in the content displayed on the user terminal  30 . In other words, the video can be played back at a good timing at which the user has read all the characters in the content. Accordingly, the video can be played back at an appropriate timing. 
     In the first embodiment and the second embodiment, the determination unit  303  repeatedly determines whether the time T end  has passed from the start of the display of the content  100  until it determines that the time T end  has passed. Alternatively, the determination unit  303  can also determine whether the time T end  has passed from a timing described later. That is to say, when the content  100  is displayed on the user terminal  30 , the determination unit  303  detects a sight line direction of the user from an image obtained by an in-camera provided on the user terminal  30 . Then, the determination-unit  303  determines whether the user&#39;s face is directed to the screen of the user terminal  30  based on the detected sight line direction of the user. When it is determined that the user&#39;s face is directed to the screen of the user terminal  30 , the determination unit  303  repeatedly determines whether the time T end  has passed from the timing at which it is determined that the user&#39;s face is directed to the screen of the user terminal  30  until it determines that the time T end  has passed. With this processing, the determination unit  303  determines whether the time T end  has passed after detecting that the user views the content  100 , so that the video can be played back at a more appropriate timing. 
     In the first embodiment and the second embodiment, the read time calculation unit of the distribution device calculates the time T end . Alternatively, the configuration in which the user terminal  30  includes a read time calculation unit and the read time calculation unit calculates the time T end  in the same manner may be employed. 
     The distribution device  20  in the first embodiment and the second embodiment is made to function by a computer  80  having the configuration as illustrated in  FIG. 13 , for example.  FIG. 13  is a hardware configuration diagram illustrating an example of the computer that executes the functions of the distribution device. The computer  80  includes a central processing unit (CPU)  81 , a random access memory (RAM)  82 , a read only memory (ROM)  83 , a hard disk drive (HDD)  84 , a communication interface (I/F)  85 , an input/output interface (I/F)  86 , and a media interface (I/F)  87 . 
     The CPU  81  operates based on programs stored in the ROM  83  or the HDD  84  so as to control the respective components. The ROM  83  stores therein a boot program that is executed by the CPU  81  when the computer  80  is activated, a program depending on the hardware of the computer  80 , and the like. 
     The HDD  84  stores therein the program that is executed by the CPU  81  and data that is used by the program. The communication interface  85  receives data from another device through the communication circuit  11  and transmits it to the CPU  81 , and transmits the data generated by the CPU  81  to another device through the communication circuit  11 . 
     The CPU  81  controls an output device such as a display and a printer and an input device such as a keyboard and a mouse through the input/output interface  86 . The CPU  81  acquires the data from the input device through the input/output interface  86 . Furthermore, the CPU  81  outputs the generated data to the output device through the input/output interface  86 . 
     The media interface  87  reads a program or data stored in a recording medium  88  and provides it to the CPU  81  through the RAM  82 . The CPU  81  loads the program on the RAM  82  from the recording medium  88  through the media interface  87  and executes the loaded program. The recording medium  88  is an optical recording medium such as a digital versatile disc (DVD) and a phase change rewritable disc (PD), a magneto-optical recording medium such as a magneto-optical disc (MO), a tape medium, a magnetic recording medium, a semiconductor memory, or the like. 
     When the computer  80  functions as the distribution device  20  in the first embodiment and the second embodiment, the CPU  81  of the computer  80  executes programs loaded on the RAM  82  so as to execute the respective functions of the content data storage unit  21  and the distribution unit  22 . Furthermore, the HDD  84  stores therein pieces of data in the content data storage unit  21 . 
     The CPU  81  of the computer  80  reads the programs from the recording medium  88  and executes them. As another example, the CPU  81  of the computer  80  may acquire the programs from another device through the communication circuit  11 . 
     In the distribution device  20  in the first embodiment and the second embodiment, the CPU in the user terminal  30  reads the content control programs included in the respective contents stored in the content data storage unit  21 , so that the user terminal  30  executes the respective functions of the determination unit  303  and the video control unit  305 . 
     According to the invention, a video can be played back at an appropriate timing. 
     Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.