Abstract:
A computer-implemented method provides logic for delivering content data. In one implementation, the computer-implemented method receives content data and metadata. The metadata is associated with a plurality of temporal positions in the content data. Based on the association, the content data is selectively delivered

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from Japanese Patent Application JP 2009-288142, filed Dec. 18, 2009, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a content providing server, a content reproducing apparatus, a content providing method, a content reproducing method, a program, and a content reproducing system. 
         [0004]    2. Description of the Related Art 
         [0005]    More and more apparatuses can handle motion pictures with the recent improvement in the performance of personal computers, as well as hard disk recorders, DVD recorders, Blu-ray recorders, TVs, and portable telephones. These apparatuses are now able to handle large quantity of data of motion picture images with the increase in the capacity of recording media, such as a nonvolatile memory and a hard disk. In many cases, metadata such as a filename of a motion picture image, a content, and a recording time are displayed in a thumbnail and icon display screen of the motion picture image, so that a user can easily recognize the content of a stored motion picture image and a motion picture image prepared for a service and the like. For example, Japanese Patent Application Laid-Open No. 2009-105580 discloses an apparatus for outputting an audio of a content currently not being viewed in such a manner that the audio is fast-forwarded by a predetermined time and is mixed with an audio of a content currently being viewed, so that the content other than the content currently being viewed can be provided in an easy-to-understand manner. 
       SUMMARY 
       [0006]    However, in the method described in Japanese Patent Application Laid-Open No. 2009-105580, the content mixed with the content currently being viewed is in synchronization with the content currently being viewed, and it is difficult to display a particular scene such as a famous scene, an interesting scene, and a popular scene. 
         [0007]    In light of the foregoing, it is desirable to provide a content providing server, a content reproducing apparatus, a content providing method, a content reproducing method, a program, and a content reproducing system, capable of dynamically changing a reproducing start position of content data. 
         [0008]    Consistent with an exemplary embodiment, a computer-implemented method delivers content data. The method includes receiving the content data and receiving metadata. The metadata is associated with a plurality of temporal positions in the content data. Based on the association, the content data is selectively delivered. As hereinabove described, according to the disclosed exemplary embodiments, the reproducing start position of the content data is determined based on a viewing parameter calculated using metadata associated with the content data. Therefore, the reproducing start position of the content data can be dynamically changed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an explanatory diagram illustrating a content reproducing system according to a first exemplary embodiment of the present invention; 
           [0010]      FIG. 2  is an explanatory diagram illustrating the content reproducing system according to the first exemplary embodiment; 
           [0011]      FIG. 3A  is an explanatory diagram illustrating the content reproducing system according to the first exemplary embodiment; 
           [0012]      FIG. 3B  is an explanatory diagram illustrating the content reproducing system according to the first exemplary embodiment; 
           [0013]      FIG. 4  is a block diagram illustrating a structure of a content providing server according to the first exemplary embodiment; 
           [0014]      FIG. 5  is an explanatory diagram illustrating a method for determining a reproducing position according to the first exemplary embodiment; 
           [0015]      FIG. 6  is an explanatory diagram illustrating a method for determining a reproducing position according to the first exemplary embodiment; 
           [0016]      FIG. 7  is an explanatory diagram illustrating a method for determining a reproducing position according to the first exemplary embodiment; 
           [0017]      FIG. 8  is a block diagram illustrating a structure of the content reproducing apparatus according to the first exemplary embodiment; 
           [0018]      FIG. 9  is an explanatory diagram illustrating an example of a display screen of the content reproducing apparatus according to the first exemplary embodiment; 
           [0019]      FIG. 10  is an explanatory diagram illustrating an example of a display screen of the content reproducing apparatus according to the first exemplary embodiment; 
           [0020]      FIG. 11  is a flowchart illustrating a method for determining a reproducing position according to the first exemplary embodiment; and 
           [0021]      FIG. 12  is a block diagram illustrating a hardware structure of a content providing server according to the first exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Hereinafter, exemplary embodiments will be described in detail with reference to the appended drawings. Note that, in this specification and the appended drawings, structural elements that have substantially the same function and structure are denoted with the same reference numerals, and repeated explanation of these structural elements is omitted. 
         [0023]    The explanation will be made in the following order:
       1. Purpose;   2. First Exemplary Embodiment;
           a. Content reproducing system;   b. Content providing server;   c. Content reproducing apparatus;   d. Example of a display screen;   e. Method for determining a reproducing position;   
           3. Hardware structure of the content providing server and the content reproducing apparatus according to the first exemplary embodiment; and   4. Summary.       
 
       1. Purpose 
       [0033]    Before explaining exemplary embodiments, a purpose of the present invention will be briefly explained. 
         [0034]    As explained above, large quantity of data of motion picture images can be handled with the recent advancement in the technology. Accordingly, techniques and methods for allowing viewers to easily recognize the contents of many motion picture images are desired. In addition to the above examples, examples of such techniques include a technique for displaying, as a still picture image or a motion picture image, the first scene of a motion picture image or a starting page of a program from which commercials or other portion of content are removed, and a method for generating a digest of a content by using only information within the content. 
         [0035]    However, in order to carry out the above method, it is necessary to analyze the content according to techniques such as audio analysis and video analysis. In methods such as audio analysis and video analysis, there is an issue in that a lot of resources are necessary for an apparatus carrying out these analyses. Moreover, in these techniques, there is also an issue in that only fixed images can be displayed that are selected or generated according to a predetermined determination criteria based on an analysis result. 
         [0036]    On the other hand, in a certain motion picture image content (for example, a movie content), a popular scene changes each day since the content is provided. Suppose a user who thinks that “I do not have a time to view the entire content, but I want to view only such popular scenes.” However, a technique for extracting and displaying such dynamically changing scenes has not yet been developed. 
         [0037]    Accordingly, in the below-explained exemplary embodiments, a technique is provided to dynamically change a position from which a content reproduction is started without using much resources. 
         [0038]    The inventor has assiduously studied in order to achieve the above technique. As a result, the inventor has conceived of the technique as explained below. In the explanation below, a content providing server, a content reproducing apparatus, and a method for determining a reproducing position according to the exemplary embodiment will be explained in detail. 
       2. First Exemplary Embodiment 
       [0039]    a. Content Reproducing System 
         [0040]    First, a content reproducing system according to the first exemplary embodiment will be explained in detail with reference to  FIGS. 1 to 3B .  FIGS. 1 to 3B  are explanatory diagrams illustrating the content reproducing system according to the present exemplary embodiment. 
         [0041]    For example, as shown in  FIG. 1 , a content reproducing system  1  includes content providing servers  10 A,  10 B, and  10 C (hereinafter referred to as “content providing servers  10 ”) and content reproducing apparatuses  20 A,  20 B, and  20 C (hereinafter referred to as “content reproducing apparatuses  20 ”). The content providing servers  10  and the content reproducing apparatuses  20  are connected to each other via a communication network  3 . 
         [0042]    The communication network  3  is a communication circuit network for allowing bidirectional communication between the content providing servers  10  and the content reproducing apparatuses  20 . Examples of communication circuit networks include public circuit networks such as the Internet, a telephone circuit network, a satellite communication circuit, and a simultaneous communication path, and dedicated circuit networks such as WAN (Wide Area Network), LAN (Local Area Network), IP-VPN (Internet Protocol-Virtual Private Network), Ethernet (registered trademark), and wireless LAN. This communication network  3  may be connected either wirelessly or via wire. That is, the content reproducing system  1  according to the present exemplary embodiment may be a part of a public service using a public circuit network such as the Internet, or may be a private one using a home network such as a LAN not disclosed to any third party. 
         [0043]    The content providing server  10  is a server for managing various kinds of content data (for example, motion picture image contents such as video contents) and various kinds of information associated with the content data (for example, metadata). The content providing server  10  provides the content data managed in the content providing server  10  and metadata of the content data to a destination device (for example, the content reproducing apparatus  20 ) in response to a request from the destination device. 
         [0044]    The content reproducing apparatus  20  may be an apparatus for reproducing motion picture image contents obtained from the content providing server  10 . In addition, the content reproducing apparatus  20  can directly obtain motion picture contents from an external apparatus (for example, a digital still camera, a digital video camera, and the like) connected to the content reproducing apparatus  20  via a predetermined interface. In addition, the content reproducing apparatus  20  can also obtain and reproduce motion picture image contents from another content reproducing apparatus  20 . 
         [0045]    For example, as shown in  FIG. 2 , this content reproducing apparatus  20  may be a portable apparatus such as a portable telephone, a portable music player, or a PDA, or may be a personal computer. The content reproducing apparatus  20  may be an image display apparatus such as a television set and an IPTV, or may be various kinds of recorders such as an HDD recorder, a DVD recorder, and a Blu-ray recorder. It should be understood that what are shown in  FIG. 2  are merely examples. The content reproducing apparatus  20  may be any apparatus as long as the apparatus can communicate via a network and reproduce motion picture image contents. 
         [0046]    As shown in  FIG. 3A , the content providing server  10  can obtain metadata such as a viewing history of content data, an operation history during content playback, comments on the content data, a viewer profile, a popularity index, and a violence rating, from various kinds of content reproducing apparatuses  20  connected via the communication network  3 . For example, such metadata may be generated based on an evaluation criterion. The content providing server  10  stores and manages the thus obtained metadata in a database  11  arranged in the content providing server  10  or outside of the server. 
         [0047]    For example, as shown in  FIG. 3B , each of the content reproducing apparatuses  20  can obtain metadata, such as the viewing history of the content data, the operation history during content playback, the comments on content data, the viewer profile, the popularity index, and the violence rating, from other content reproducing apparatuses  20  connected via the communication network  3 . 
         [0048]    In  FIGS. 1 to 3B , the communication network  3  makes connection between the content providing server  10  and the content reproducing apparatus  20  and between the content reproducing apparatuses  20 . Alternatively, these apparatuses may be directly connected without relying on any communication network. 
         [0049]    In the content reproducing system  1 , according to the present exemplary embodiment, at least one of the content providing servers  10  and the content reproducing apparatuses  20  may have a function for determining a reproducing position based on a viewing parameter as explained later. 
         [0050]    b. Content Providing Server 
         [0051]    Subsequently, the structure of the content providing server  10  according to the present exemplary embodiment will be explained in detail with reference to  FIG. 4 .  FIG. 4  is a block diagram illustrating the structure of the content providing server  10  according to the present exemplary embodiment. 
         [0052]    For example, as shown in  FIG. 4 , the content providing server  10  according to the present exemplary embodiment includes a metadata obtaining unit  101 , a viewing parameter calculation unit  103 , a reproducing position determining unit  105 , a content data distribution unit  107 , and a storage unit  109 . Further, the content providing server  10  may include a content analysis unit for performing various kinds of audio analyses and video analyses on content data. Further, the content providing server  10  may include not only the above processing units but also one or a plurality of processing units for distributing and managing the content data. 
         [0053]    The metadata obtaining unit  101  is realized with, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a communication device, and the like. The metadata obtaining unit  101  obtains various kinds of metadata associated with content data from the content reproducing apparatus  20 . The metadata obtaining unit  101  obtains metadata at any timing. For example, the metadata obtaining unit  101  may obtain metadata when some kind of communication is performed by the content reproducing apparatus  20 , or may periodically obtain metadata with a predetermined time interval. Alternatively, the metadata obtaining unit  101  may obtain metadata in response to a predetermined operation performed by a user. 
         [0054]    Examples of metadata obtained by the metadata obtaining unit  101  are as follows: 
         [0055]    (i) viewing history of contents (including history information about viewing scenes of contents and operation history information during content reproduction); 
         [0056]    (ii) user feedback information such as comments and the degree of recommendation about contents; 
         [0057]    (iii) information about preference of a user (for example, attribute information such as preferred genres); 
         [0058]    (iv) a viewer profile; 
         [0059]    (v) a popularity index; 
         [0060]    (vi) a violence rating; and 
         [0061]    (iv) others types of metadata appropriate to metadata obtaining unit  101 . 
         [0062]    The metadata obtaining unit  101  transfers the above-described metadata obtained from each of the content reproducing apparatuses  20  to the later-explained viewing parameter calculation unit  103 . Further, the metadata obtaining unit  101  may record the obtained metadata in a database and the like stored in the later-explained storage unit  109 . 
         [0063]    The viewing parameter calculation unit  103  is constituted with, for example, a CPU, a ROM, a RAM, and the like. The viewing parameter calculation unit  103  uses predetermined metadata associated with content data to calculate viewing parameters serving as an index representing the state of viewing of the content data. At a temporal position of the content data (i.e., an elapsed time from the beginning of the content data), this viewing parameter is calculated for a certain continuous time interval or calculated discontinuously. The metadata used for the calculation of the viewing parameters is any one of metadata obtained by the metadata obtaining unit  101  from the content reproducing apparatus  20  and metadata recorded in the database stored in the later-explained storage unit  109 . 
         [0064]    The viewing parameter calculation unit  103  can use any available metadata as the metadata used during calculation of viewing parameters. The viewing parameter calculation unit  103  uses, for example, metadata (viewing rate, viewing history, the degree of excitement, preference attribute, the number of comments, other metadata), as shown in  FIG. 5 , in order to calculate the viewing parameter p. Among the above parameters, the viewing history includes history information about viewing scenes, operation history information during viewing of the content data, and the like. Further, the preference attribute is metadata reflecting individual preferences of a user. For example, the preference attribute may be a numerical value representing the degree of agreement between the content data and a user&#39;s preference. The other metadata include, for example, various kinds of analyses generated by an analysis unit included within the content providing server  10 , and various kinds of analyses results of the content data generated by a content reproducing apparatus  20  having an analysis unit. 
         [0065]    The viewing parameter calculation unit  103  normalizes and uses metadata used for calculation of these viewing parameters. Further, the viewing parameter calculation unit  103  may calculate variations of the normalized metadata. 
         [0066]    The viewing parameter calculation unit  103  calculates the viewing parameter p according to any calculation method by using these metadata, the variations of the metadata, and the like. For example, the calculation method as shown in  FIG. 5  can also be used. In the calculation method for calculating the viewing parameter p as shown in  FIG. 5 , a linear combination of the metadata and the variations of the metadata multiplied by predetermined weighting coefficients W is calculated as the viewing parameter. Herein, in the expression as shown in  FIG. 5 , W x     —     t  represents a weighting coefficient for metadata x at a time t. W 1  represents a weighting coefficient corresponding to a value of metadata. W 2  represents a weighting coefficient corresponding to a variation of metadata. 
         [0067]    Herein, the weighting coefficient may be a constant value regardless of the time t, or may change according to the time t. The weighting coefficient may be determined statistically through various kinds of mechanical learning techniques, or may be determined according to a judgment of a user. Alternatively, the weighting coefficient may be randomly determined, so that a calculated viewing parameter may be based on a factor of randomness. As necessary, any one of the coefficients W x     —     t , W 1 , and W 2  may be zero. For example,  FIG. 6  illustrates an example of weighting coefficient for metadata a about a viewing rate. In  FIG. 6 , the weighting coefficient is small at the beginning of a content, and thereafter, the weighting coefficient is rapidly increased to a large value. This setting is based on an experience that “the viewing rate is likely to be high at the beginning of a content”. 
         [0068]    In the expression shown in  FIG. 5 , the viewing parameter p becomes larger for a scene which attracts many viewers in some sense. 
         [0069]    Herein, the viewing parameter calculation unit  103  calculates the viewing parameter p again and again, and updates the viewing parameter p. The viewing parameter calculation unit  103  can calculate the viewing parameter p again (that is, update the viewing parameter p) at any timing. For example, the viewing parameter calculation unit  103  may calculate the viewing parameter again with a predetermined time interval. Alternatively, the viewing parameter calculation unit  103  may calculate the viewing parameter again every time the content providing server  10  performs some kind of communication with the content reproducing apparatus  20 . Alternatively, the viewing parameter calculation unit  103  may calculate the viewing parameter again in response to an instruction given by a user. The viewing parameter calculation unit  103  can reflect a behavior of a user on each occasion by thus calculating the viewing parameter again at any timing. 
         [0070]    The viewing parameter calculation unit  103  notifies the viewing parameter p thus calculated to the later-explained reproducing position determining unit  105  every time the viewing parameter calculation unit  103  calculates the viewing parameter p. Further, the viewing parameter calculation unit  103  may associate the calculated viewing parameter p with information about the calculated time, and record the calculated viewing parameter p in the storage unit  109 . 
         [0071]    The reproducing position determining unit  105  is constituted with, for example, a CPU, a ROM, a RAM, and the like. When the viewing parameter calculation unit  103  notifies the viewing parameter p to the reproducing position determining unit  105 , the reproducing position determining unit  105  determines, based on the notified viewing parameter p, a temporal position from which the content reproducing apparatus  20  starts reproduction of a content. More specifically, the reproducing position determining unit  105  determines a temporal position t in which a predetermined condition (that is, a selection criterion) is satisfied in a viewing parameter p(t), and the temporal position t is adopted as a temporal position from which reproduction of the content is started. 
         [0072]    The predetermined condition for determining a reproducing start position can be appropriately determined. For example, the reproducing position determining unit  105  may detect a temporal position t that yields an extreme value of the viewing parameter p (that is, a first temporal position) and determine the reproducing position based on the time t that yields this extreme value. 
         [0073]    More specifically, the reproducing position determining unit  105  detects a plurality of temporal positions yielding extreme values, such as a time t_max corresponding to a peak that yields the maximum value of the viewing parameter p and a time t — 2nd corresponding to a peak that yields the second largest value (that is, a second temporal positon). Subsequently, for example, the reproducing position determining unit  105  can determine the time t_max yielding the maximum value of the viewing parameter p or a time close to t_max, and can adopt the time t_max or the time close to t_max as the reproducing start position. 
         [0074]    How much time before a certain time t (for example, t_max) a reproduction is started (for example, in a case where a trailer is reproduced, how much time after the certain time t the reproduction is stopped) can be appropriately determined. For example, the reproducing position determining unit  105  may determine the range of reproduction according to the width of the peak yielding the extreme value. Accordingly, the reproduction range can be appropriately set, so that, for example, a portion continuously having a high viewing parameter is reproduced for a long time. 
         [0075]    Alternatively, the reproducing position determining unit  105  may appropriately change a temporal position to be selected, so that, for example, at a certain point of time, a time close to a time yielding t_max is adopted as the reproducing start position, and at another point of time, a time close to a time yielding t — 2nd is adopted as the reproducing start position. In such case, the reproducing start position is based on a factor of randomness, which allows a user to enjoy viewing a reproduction of any one of the plurality of scenes which attract viewers. 
         [0076]    For example, the reproducing position determining unit  105  determines a time close to a time t yielding t_max and adopts the time as the reproducing start position, and a viewing parameter p, as shown in the upper part of  FIG. 7 , is received from the viewing parameter calculation unit  103 . In this case, the reproducing position determining unit  105  determines a time close to a time t yielding t_max, and adopts the time as the reproducing start position, so that a corresponding “scene  1 ” (that is, a first portion of the content data) is displayed on a display screen of a viewer. As explained above, the viewing parameter p is a parameter that is updated whenever necessary, and accordingly, at a certain point of time, the viewing parameter p changes, as shown in the lower part of  FIG. 7 . When the parameter in the upper part of  FIG. 7  changes to the parameter in the lower part of  FIG. 7 , the position yielding t_max in the upper part of  FIG. 7  yields t — 2nd in the lower part of  FIG. 7 , and the position yielding t — 3rd in the upper part of  FIG. 7  yields t_max in the lower part of  FIG. 7 . At this occasion, the reproducing position determining unit  105  determines a position close to t_max in the lower part of  FIG. 7 , and adopts the position as the reproducing start position, so that a corresponding “scene  2 ” is displayed on the display screen of the viewer (that is, the second portion of the content data). 
         [0077]    When the reproducing position determining unit  105  determines the reproducing start position based on a viewing parameter p at a certain point of time, the reproducing position determining unit  105  provides information about the determined reproducing start position to the later-explained content data distribution unit  107 . Further, the reproducing position determining unit  105  may store the information about the determined reproducing start position in the storage unit  109  and the like. 
         [0078]    As described above, the reproducing position determining unit  105  according to the present exemplary embodiment determines the reproducing start position based on the viewing parameter, i.e., a parameter updated in succession, every time the viewing parameter is updated. Accordingly, the content providing server  10  according to the present exemplary embodiment can dynamically change the reproducing start position of the content. 
         [0079]    Referring back to  FIG. 4 , the content data distribution unit  107  will be explained. 
         [0080]    The content data distribution unit  107  is realized with, for example, a CPU, a ROM, a RAM, a communication device, and the like. In response to a request made by the content reproducing apparatus  20 , the content data distribution unit  107  distributes content data, which is stored by the content providing server  10  in an external storage device or the storage unit  109 , to the content reproducing apparatus  20  having made the request. Further, the content data distribution unit  107  can also distribute not only the content data, but also the metadata associated with the distributed content data. In response to a request made by the content reproducing apparatus  20 , the content data distribution unit  107  may distribute only the metadata associated with some content data to the content reproducing apparatus  20  having made the request. As described above, the content data distribution unit  107  is a processing unit playing the role of providing content data, and therefore, the content data distribution unit  107  can calculate parameters, such as viewing rate, of the contents. 
         [0081]    When the content reproducing apparatus  20  requests data corresponding to a main part of the content data from the beginning of the content data, the content data distribution unit  107  distributes the corresponding content data from the beginning. Alternatively, there may be a case where the content reproducing apparatus  20  requests distribution of the main part of the content or a representation of the content (for example, a thumbnail image), partway through the content data. In such case, the content data distribution unit  107  starts distribution of the content data from the portion corresponding to the requested temporal position, based on the information about the reproducing start position notified by the reproducing position determining unit  105 . Accordingly, when the content reproducing apparatus  20  requests displaying of a list of thumbnail images and a trailer on the display screen of the content reproducing apparatus  20 , the content data distribution unit  107  can distribute the content data from the portion corresponding to the scene which currently attracts interest. 
         [0082]    The storage unit  109  is an example of a storage device of the content providing server  10 . This storage unit  109  stores various kinds of content data of the content providing server  10  and various kinds of metadata and the like including thumbnail images and trailers associated with content data. It should be noted that the metadata may be stored in the storage unit  109  in a form of database, together with metadata obtained by the metadata obtaining unit  101  from the content reproducing apparatus  20 . Further, this storage unit  109  may store various parameters or progress of processing that are necessary to be stored while the content providing server  10  performs certain processing, and may store various kinds of databases and so on as necessary. This storage unit  109  can be freely read and written by each processing unit of the content providing server  10  according to the present exemplary embodiment. 
         [0083]    Examples of the functions of the content providing server  10  according to the present exemplary embodiment have been hereinabove explained. Each of the above constituent elements may be made with a generally-used member and circuit, or may be made with hardware dedicated for the function of each constituent element. Alternatively, all of the functions of the constituent elements may be performed by a CPU and the like. Therefore, the used configuration may be changed as necessary in accordance with the state of art at the time when the present exemplary embodiment is carried out. 
         [0084]    It is possible to make a computer program for realizing the functions of the above-described content providing server according to the present exemplary embodiment, and the computer program can be implemented on a personal computer and the like. Further, a computer-readable recording medium having stored such a computer program can be provided. Examples of recording media include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. Further, for example, the above computer program may be distributed by a network, without using any recording medium. 
         [0085]    c. Content Reproducing Apparatus 
         [0086]    Subsequently, the structure of the content reproducing apparatus  20  will be explained with reference to  FIG. 8 , in a case where the content reproducing apparatus  20  has a function of determining the reproducing start position of the content.  FIG. 8  is a block diagram illustrating the functions of the content reproducing apparatus  20  according to the present exemplary embodiment. 
         [0087]    As shown in  FIG. 8 , the content reproducing apparatus  20  includes a metadata transmission reception unit  201 , a viewing parameter calculation unit  203 , a reproducing position determining unit  205 , a content data obtaining unit  207 , a content reproducing unit  209 , a display control unit  211 , and a storage unit  213 . Further, the content reproducing apparatus  20  may include a content analysis unit for performing various kinds of audio analyses and video analyses on contents. 
         [0088]    The metadata transmission reception unit  201  is realized with, for example, a CPU, a ROM, a RAM, a communication device, and the like. The metadata transmission reception unit  201  receives metadata from the content providing server  10  or another content reproducing apparatus  20  at any timing, and transmits metadata to the content providing server  10  or another content reproducing apparatus  20 . When communication is performed between the content providing server  10  and another content reproducing apparatus, this metadata transmission reception unit  201  transmits and receives metadata in response to a user&#39;s operation or at a predetermined time interval. When the metadata transmission reception unit  201  transmits metadata, the metadata transmission reception unit  201  transmits metadata stored in the later-explained storage unit  213  to a predetermined apparatus. When the metadata transmission reception unit  201  receives metadata from another apparatus, the metadata transmission reception unit  201  provides the received metadata to the later-explained viewing parameter calculation unit  203 . Further, the metadata transmission reception unit  201  may store the metadata obtained from another apparatus to the later-explained storage unit  213 . 
         [0089]    The viewing parameter calculation unit  203  is realized with, for example, a CPU, a ROM, a RAM, and the like. The viewing parameter calculation unit  203  according to the present exemplary embodiment has the same structure as the viewing parameter calculation unit  103  of the content providing server  10  according to the present exemplary embodiment, and is a processing unit achieving the same effects. Therefore, the detailed description thereof is omitted in the explanation below. 
         [0090]    The reproducing position determining unit  205  is realized with, for example, a CPU, a ROM, a RAM, and the like. The reproducing position determining unit  205  according to the present exemplary embodiment has the same structure as the reproducing position determining unit  105  of the content providing server  10  according to the present exemplary embodiment, and is a processing unit achieving the same effects. Therefore, the detailed description thereof is omitted in the explanation below. 
         [0091]    The content data obtaining unit  207  is realized with, for example, a CPU, a ROM, a RAM, a communication device, and the like. The content data obtaining unit  207  obtains content data that can be reproduced by the content reproducing apparatus  20  from the content providing server  10  or another content reproducing apparatus  20 . Further, the content data obtaining unit  207  can also directly obtain content data from a digital camera and the like connected to the content reproducing apparatus  20 . The content data obtaining unit  207  transmits the obtained content data to the later-explained content reproducing unit  209 . The content data obtaining unit  207  may store the obtained content data to the later-explained storage unit  213  and the like. 
         [0092]    The content reproducing unit  209  is realized with, for example, a CPU, a ROM, a RAM, and the like. The content reproducing unit  209  reproduces content data obtained by the content data obtaining unit  207  or content data stored in the content reproducing apparatus  20 , so that the later-explained display control unit  211  displays the content on the display screen. 
         [0093]    When a viewer desires to view the content from the beginning, the content reproducing unit  209  reproduces the corresponding content data from the beginning. Alternatively, there may be a case where the user desires to view the main part of the content data or thumbnails of the content, partway through the content data. In such case, the content reproducing unit  209  starts reproduction of the content data from the portion corresponding to the desired temporal position, based on the information about the reproducing start position notified by the reproducing position determining unit  205 . 
         [0094]    The display control unit  211  is realized with, for example, a CPU, a ROM, a RAM, and the like. The display control unit  211  is a processing unit for performing display control on a display content that is displayed by a display unit (not shown) of the content reproducing apparatus  20  according to the present exemplary embodiment. In response to a user&#39;s operation and an instruction given by the content reproducing unit  209 , the display control unit  211  can display a list of content data that can be reproduced on the display screen, display a trailer of content data that can be reproduced on the display screen, and display a reproduction screen of content data on the display screen. In the explanation below, the control processing of the display screen carried out by this display control unit  211  will be explained again. 
         [0095]    The storage unit  213  is an example of storage device of the content reproducing apparatus  20 . This storage unit  213  stores various kinds of content data possessed by the content reproducing apparatus  20  and various kinds of metadata and the like including thumbnail images and trailers associated with content data. It should be noted that the metadata may be stored in the storage unit  213  in a form of database, together with metadata obtained by the metadata transmission reception unit  201  from another apparatus. Further, this storage unit  213  may store various parameters or progress of processing that are necessary to be stored while the content reproducing apparatus  20  performs certain processing, and may store various kinds of databases and so on as necessary. This storage unit  213  can be freely read and written by each processing unit of the content reproducing apparatus  20  according to the present exemplary embodiment. 
         [0096]    Examples of the functions of the content reproducing apparatus  20  according to the present exemplary embodiment have been hereinabove explained. Each of the above constituent elements may be made with a generally-used member and circuit, or may be made with hardware dedicated for the function of each constituent element. Alternatively, all of the functions of the constituent elements may be performed by a CPU and the like. Therefore, the used configuration may be changed as necessary in accordance with the state of art at the time when the present exemplary embodiment is carried out. 
         [0097]    In a case where the content reproducing apparatus  20  does not have the above-described viewing parameter calculation unit  203 , and has only the reproducing position determining unit  205 , the reproducing position determining unit  205  can determine a reproducing position by using a viewing parameter obtained from the content providing server  10 . Alternatively, there may be a case where the content reproducing apparatus  20  has neither the viewing parameter calculation unit  203  nor the reproducing position determining unit  205 . In such case, when the content reproducing apparatus  20  obtains content data from the content providing server  10 , the content reproducing apparatus  20  may notify a desired reproducing method of a content, and may reproduce the obtained content data as it is. 
         [0098]    It is possible to make a computer program for realizing the functions of the above-described content reproducing apparatus according to the present exemplary embodiment, and the computer program can be implemented on a personal computer and the like. Further, a computer-readable recording medium having stored such a computer program can be provided. Examples of recording media include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. Further, for example, the above computer program may be distributed by a network, without using any recording medium. 
         [0099]    d. Examples of Display Screen 
         [0100]    Subsequently, examples of display screens displayed on the display unit according to the display control of the display control unit  211  of the present exemplary embodiment will be explained in detail with reference to  FIGS. 9 and 10 . 
         [0101]      FIGS. 9 and 10  are explanatory diagrams illustrating examples of display screens of the content reproducing apparatus  20  according to the present exemplary embodiment. 
         [0102]    In the example below, the content reproducing apparatus  20  mainly reproduces content data at around a time at which the viewing parameter p has a large value. At this occasion, when the content reproducing unit  209  displays a representation of the content data, for example, thumbnails of the content data, on the display screen, the content reproducing unit  209  changes a scene to be displayed as thumbnail images, based on the viewing parameter obtained from the viewing parameter calculation unit  203 . As a result, the display control unit  211  performs control so as to display thumbnail images on the display screen according to the viewing parameter, so that the content data displayed on the display screen changes on each occasion. As a result, the viewer of the content reproducing apparatus  20  can see different thumbnail images, which are displayed on each occasion even if the content is the same. 
         [0103]    The display control unit  211  may classify the sizes of objects such as thumbnails displayed on the display screen into several grades according to the magnitude of the viewing parameter. At this occasion, the display control unit  211  changes the size of an object according to the magnitude of the viewing parameter corresponding to the content data of which object is displayed. At this occasion, the maximum value of the viewing parameter or the average value of the viewing parameter may be used as the magnitude of the viewing parameter. 
         [0104]    For example, it is assumed that there are three kinds of content data, i.e., content data A to C, and the viewing parameter of the content B is larger than those of the content data A and C. At this occasion, the display control unit  211  may display a larger thumbnail image  303  corresponding to a thumbnail B than thumbnail images  301  corresponding to thumbnails A and C. 
         [0105]    Further, as shown in  FIG. 9 , the display control unit  211  may move (e.g., rotate) an object having a high viewing rate or having a large number of comments, and may move an object corresponding to a content whose viewing parameter has been updated. Accordingly, viewers can easily find content data which attracts interest in some sense. 
         [0106]    As shown in  FIG. 10 , it is assumed that two kinds of thumbnail images  301  are displayed on the display screen, and one of the thumbnail images  301  is selected by a position specifying object  305 . At this occasion, the display control unit  211  may request the content reproducing unit  209  to start reproduction of a content corresponding to the selected thumbnail image. 
         [0107]    At this occasion, the display control unit  211  may change the display screen and display a new window  307  on the display screen, so as to display button objects  309  for allowing a viewer to select how a content is to be reproduced. In the example shown in the middle part of  FIG. 10 , three kinds of button objects  309 , such as “play content data from the beginning,” “play content data from recommended position,” and “play content data according to preference,” are displayed as the button objects  309 . When the viewer selects a button such as “play content data from recommended position,” the content reproducing unit  209  starts reproduction of the content data from the reproducing start position determined by the reproducing position determining unit  205 . 
         [0108]    When a user selects a predetermined button or a button for setting change, the display control unit  211  may display a setting window  311  on the display screen as shown in the lower part of  FIG. 10 . This setting window  311  displays button objects  313  for displaying various kinds of setting screens such as parameter adjustment, change of weighting coefficient, reference of viewing parameter, and change of calculation method. The viewer can perform a predetermined operation on the content reproducing apparatus  20  by selecting these button objects  313 . 
         [0109]    As described above, the display control unit  211  according to the present exemplary embodiment can perform various kinds of display controls such as changing of a display form of an object by using a viewing parameter. 
         [0110]    e. Method for Determining a Reproducing Position 
         [0111]    Subsequently, a flow of a method for determining a reproducing position, performed by the content providing server  10  and the content reproducing apparatus  20  according to the present exemplary embodiment, will be briefly explained with reference to  FIG. 11 .  FIG. 11  is a flow diagram illustrating the method for determining a reproducing position of content data according to the present exemplary embodiment. In  FIG. 11 , the content reproducing apparatus  20  determines a reproduction position of the content data and starts reproduction of the content data. However, the flow of determining the reproduction position can be similarly performed by the content providing server  10 . 
         [0112]    First, the content reproducing apparatus  20  initializes the reproducing position before the content reproducing apparatus  20  determines the reproducing position (step S 201 ). Subsequently, the content reproducing apparatus  20  determines whether to use a viewing parameter or not in order to determine the reproducing position (step S 103 ). When a setting is made not to use the viewing parameter, or when there is no viewing parameter, the content reproducing unit  209  of the content reproducing apparatus  20  starts reproduction of the content data from the initial position, i.e., from the beginning of the content data (step S 105 ). 
         [0113]    On the other hand, when there is a viewing parameter, a determination is made as to whether a time t is larger than a length t_end of the content data (step S 107 ). When the time t is larger than t_end, the viewing parameter calculation unit  203  does not calculate the viewing parameter, and the content reproducing apparatus  20  performs step S 115 , as explained later. 
         [0114]    When the time t is smaller than t_end, the viewing parameter calculation unit  203  calculates the viewing parameter according to the method as shown in  FIG. 5  (step S 109 ). In a case where the content reproducing apparatus  20  does not have the viewing parameter calculation unit  203 , a calculated viewing parameter is obtained from the content providing server  10  or another content reproducing apparatus  20  (step S 109 ). 
         [0115]    Subsequently, the viewing parameter calculation unit  203  determines whether there is any available viewing parameter other than the viewing parameter calculated by the content reproducing apparatus  20  (step S 111 ). When there is an available viewing parameter, the content reproducing apparatus  20  obtains the viewing parameter from a corresponding apparatus (step S 113 ), and the viewing parameter calculation unit  203  calculates the viewing parameter again. 
         [0116]    Subsequently, the reproducing position determining unit  205  determines a reproducing start position (e.g., a reproducing scene), a display method onto the screen, a display effect, and the like, based on the viewing parameter calculated by the viewing parameter calculation unit  203 , or based on the viewing parameter obtained from the outside (step S 115 ). Thereafter, the reproducing position determining unit  205  notifies information including the determined reproducing start position to the content reproducing unit  209 . 
         [0117]    The content reproducing unit  209  uses the notified information including the reproducing start position to start reproduction of the content data from the position determined by the reproducing position determining unit  205  (step S 117 ). 
         [0118]    As described above, in the method for determining a reproducing position according to the present exemplary embodiment, the reproducing start position of the content data can be determined by using the viewing parameter calculated using various kinds of metadata. Accordingly, in the method for determining the reproducing position according to the present exemplary embodiment, the reproducing start position of the content can be dynamically changed. 
       3. Hardware Configuration 
       [0119]    Next, the hardware configuration of the content providing server  10  according to an exemplary embodiment will be described in detail with reference to  FIG. 13 .  FIG. 13  is a block diagram for illustrating the hardware configuration of the content providing server  10  according to the exemplary embodiment. 
         [0120]    The content providing server  10  mainly includes a CPU  901 , a ROM  903 , and a RAM  905 . Furthermore, the content providing server  10  also includes a host bus  907 , a bridge  909 , an external bus  911 , an interface  913 , an input device  915 , an output device  917 , a storage device  919 , a drive  921 , a connection port  923 , and a communication device  925 . 
         [0121]    The CPU  901  serves as an arithmetic processing apparatus and a control device, and controls the overall operation or a part of the operation of the content providing server  10  according to various programs recorded in the ROM  903 , the RAM  905 , the storage device  919 , or a removable recording medium  927 . The ROM  903  stores programs, operation parameters, and the like used by the CPU  901 . The RAM  905  primarily stores programs used in execution of the CPU  901  and parameters and the like varying as appropriate during the execution. These are connected with each other via the host bus  907  configured from an internal bus such as a CPU bus or the like. 
         [0122]    The host bus  907  is connected to the external bus  911  (e.g., a PCI (Peripheral Component Interconnect/Interface) bus) via the bridge  909 . 
         [0123]    The input device  915  is an operation means operated by a user, such as a mouse, a keyboard, a touch panel, buttons, a switch and a lever. Also, the input device  915  may be a remote control means (e.g., a so-called remote control) using, for example, infrared light or other radio waves, or may be an externally connected device  929  such as a mobile phone or a PDA conforming to the operation of the content providing server  10 . Furthermore, the input device  915  generates an input signal based on, for example, information which is input by a user with the above operation means, and is configured from an input control circuit for outputting the input signal to the CPU  901 . The user of the content providing server  10  can input various data to the content providing server  10  and can instruct the content providing server  10  to perform processing by operating this input apparatus  915 . 
         [0124]    The output device  917  is configured from a device capable of visually or audibly notifying acquired information to a user. Examples of such device include display devices such as a CRT display device, a liquid crystal display device, a plasma display device, an EL display device and lamps, audio output devices such as a speaker and a headphone, a printer, a mobile phone, a facsimile machine, and the like. For example, the output device  917  outputs a result obtained by various processings performed by the content providing server  10 . More specifically, the display device displays, in the form of texts or images, a result obtained by various processes performed by the content providing server  10 . On the other hand, the audio output device converts an audio signal such as reproduced audio data and sound data into an analog signal, and outputs the analog signal. 
         [0125]    The storage device  919  is a device for storing data configured as an example of a storage unit of the content providing server  10  and is used to store data. The storage device  919  is configured from, for example, a magnetic storage device such as a HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device, or a magneto-optical storage device. This storage device  919  stores programs to be executed by the CPU  901 , various data, and various data obtained from the outside. 
         [0126]    The drive  921  is a reader/writer for recording medium, and is embedded in the content providing server  10  or attached externally thereto. The drive  921  reads information recorded in the attached removable recording medium  927  such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, and outputs the read information to the RAM  905 . Furthermore, the drive  921  can write in the attached removable recording medium  927  such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory. The removable recording medium  927  is, for example, a DVD medium, an HD-DVD medium, or a Blu-ray medium. The removable recording medium  927  may be a CompactFlash (CF; registered trademark), a flash memory, an SD memory card (Secure Digital Memory Card), or the like. Alternatively, the removable recording medium  927  may be, for example, an IC card (Integrated Circuit Card) equipped with a non-contact IC chip or an electronic appliance. 
         [0127]    The connection port  923  is a port for allowing devices to directly connect to the content providing server  10 . Examples of the connection port  923  include a USB (Universal Serial Bus) port, an IEEE1394 port, a SCSI (Small Computer System Interface) port, and the like. Other examples of the connection port  923  include an RS-232C port, an optical audio terminal, an HDMI (High-Definition Multimedia Interface) port, and the like. By the externally connected apparatus  929  connecting to this connection port  923 , the content providing server  10  directly obtains various data from the externally connected apparatus  929  and provides various data to the externally connected apparatus  929 . 
         [0128]    The communication device  925  is a communication interface configured from, for example, a communication device for connecting to a communication network  931 . The communication device  925  is, for example, a wired or wireless LAN (Local Area Network), Bluetooth (registered trademark), a communication card for WUSB (Wireless USB), or the like. Alternatively, the communication device  925  may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), a modem for various communications, or the like. This communication device  925  can transmit and receive signals and the like in accordance with a predetermined protocol such as TCP/IP on the Internet and with other communication devices, for example. The communication network  931  connected to the communication device  925  is configured from a network and the like, which is connected via wire or wirelessly, and may be, for example, the Internet, a home LAN, infrared communication, radio wave communication, satellite communication, or the like. 
         [0129]    Heretofore, an example of the hardware configuration capable of realizing the functions of the content providing server  10  according to the exemplary embodiment of the present invention has been shown. Each of the structural elements described above may be configured using a general-purpose material, or may be configured from hardware dedicated to the function of each structural element. Accordingly, the hardware configuration to be used can be changed as appropriate according to the technical level at the time of carrying out the present exemplary embodiment. 
         [0130]    The hardware structure of the content reproducing apparatus according to the exemplary embodiment of the present invention is the same as the hardware structure of the content providing server according to the exemplary embodiment of the present invention. Therefore, the detailed description thereof is omitted. 
       4. Summary 
       [0131]    As described above, in the method for determining the reproducing position according to the exemplary embodiment of the present invention, the viewing parameter is calculated for each content data and used as an index. Accordingly, reproduced scenes and displayed scenes can be dynamically changed. Therefore, for example, a viewer of content data can immediately view a scene which other people are interested in and a scene currently attracting interest. A server and a content distributor can provide a viewer&#39;s apparatus (content reproducing apparatus) with a scene or a time which the server and the content distributor want viewers to be interested in. 
         [0132]    Since information such as metadata can be obtained not only from the content providing server but also from another content reproducing apparatus, the information about other people&#39;s evaluation obtained from these apparatuses can be reflected in the viewing parameter. 
         [0133]    It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof. 
         [0134]    For example, in the above exemplary embodiments, various kinds of metadata are used to dynamically determine a reproducing position of a content. However, the system according to the present invention can also be applied when various kinds of metadata are used to select a similar scene or comment. 
         [0135]    The present application contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2009-288142 filed in the Japan Patent Office on Dec. 18, 2009, the entire content of which is hereby incorporated by reference.