Abstract:
Disclosed herein is a content transmission apparatus, including: a retaining section adapted to retain a multi viewpoint video content formed from a plurality of viewpoint videos imaged simultaneously by a plurality of different video cameras; a production section adapted to produce a VRT including acquisition destination information of the viewpoint videos which configure the multi viewpoint video content, VRT standing for View Relation Table; a supplying section adapted to supply the produced VRT to a content reproduction apparatus; a broadcasting section adapted to broadcast one or plural ones of the viewpoint videos which configure the retained multi viewpoint video content; and a delivery section adapted to deliver one or plural ones of the viewpoint videos which configure the retained multi viewpoint video content through a network.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of priority of Provisional Application Ser. Nos. 61/388,999, filed on Oct. 1, 2010 and 61/504,481, filed on Jul. 5, 2011, the entire contents of which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to a content transmission apparatus, a content transmission method, a content reproduction apparatus, a content reproduction method, a program and a content delivery system, and particularly to a content transmission apparatus, a content transmission method, a content reproduction apparatus, a content reproduction method, a program and a content delivery system which make it possible for a user of the content reproduction apparatus to view a content with an arbitrary picture frame. 
         [0003]    In the past, in a video content delivery service represented by a video on demand service through a television broadcast, the Internet or the like, it is possible for a viewer to view a video content only with a picture frame produced by the broadcasting side. 
         [0004]    It is to be noted that video contents which use package media such as a DVD (digital versatile disc) or a BD (blu-ray disc) include those video contents in which a plurality of videos obtained by imaging a sports event, a concert place or the like, which is determined as an object to be imaged, from a plurality of different viewpoints (angles) (so-called multi-angle video) (refer to, for example, Japanese Patent Laid-Open No. 2009-135946). 
         [0005]    In the case where a video content ready for a multi-angle video is reproduced, a viewer can select and view one of the plural videos. However, even in the case of a video content ready for a multi-angle video, the viewer cannot view a video with an arbitrary picture frame, that is, in a state in which it is imaged from an arbitrary viewpoint. 
       SUMMARY 
       [0006]    Incidentally, with regard to video contents, appearance of such a viewing form that not only a video of a broadcasted picture frame or videos of multi-angles prepared in advance can be selected but also a video imaged from an arbitrary viewpoint conforming to the liking of each viewer can be viewed is demanded. 
         [0007]    In particular, for example, there is a demand to watch a scene, which is not currently displayed on the screen, on the right of a scene (object to be imaged) currently displayed on the screen or to watch a scene (object to be imaged) currently displayed on the screen from the side. 
         [0008]    The present disclosure has been made in view of such a situation as described above and makes it possible to view a video in a state in which it is imaged from an arbitrary viewpoint. 
         [0009]    A content transmission apparatus according to a first embodiment of the present disclosure is a content transmission apparatus, including a retaining section adapted to retain a multi viewpoint video content formed from a plurality of viewpoint videos imaged simultaneously by a plurality of different video cameras, a production section adapted to produce a VRT (View Relation Table) including acquisition destination information of the viewpoint videos which configure the multi viewpoint video content, a supplying section adapted to supply the produced VRT to a content reproduction apparatus, a broadcasting section adapted to broadcast one or plural ones of the viewpoint videos which configure the retained multi viewpoint video content, and a delivery section adapted to deliver one or plural ones of the viewpoint videos which configure the retained multi viewpoint video content through a network. 
         [0010]    The production section may produce the VRT which further includes a viewpoint string type representative of a relationship between an adjacent viewpoint video imaged adjacent each of the viewpoint videos which configure the video content and the viewpoint video. 
         [0011]    The viewpoint string type may be Panorama, Theater, Parallel or Separated. 
         [0012]    The broadcasting section or the delivery section may serve also as the supplying section. 
         [0013]    A content transmission method according to the first embodiment of the present disclosure is a content transmission method for a content transmission apparatus which supplies a multi viewpoint video content formed from a plurality of viewpoint videos imaged simultaneously by a plurality of different video cameras to a content reproduction apparatus, including producing a VRT including acquisition destination information of the viewpoint videos which configure the multi viewpoint video content, supplying the produced VRT to a content reproduction apparatus, broadcasting one or plural ones of the viewpoint videos which configure the retained multi viewpoint video content, and delivering one or plural ones of the viewpoint videos which configure the retained video content through a network, carried out by the content transmission apparatus. 
         [0014]    A program according to the first embodiment of the present disclosure is a program for causing a computer to function as a retaining section adapted to retain a multi viewpoint video content formed from a plurality of viewpoint videos imaged simultaneously by a plurality of different video cameras, a production section adapted to produce a VRT including acquisition destination information of the viewpoint videos which configure the multi viewpoint video content, a supplying section adapted to supply the produced VRT to a content reproduction apparatus, a broadcasting section adapted to broadcast one or plural ones of the viewpoint videos which configure the retained multi viewpoint video content, and a delivery section adapted to deliver one or plural ones of the viewpoint videos which configure the retained video content through a network. 
         [0015]    In the first embodiment of the present disclosure, a VRT including acquisition destination information of viewpoint videos which configure a multi viewpoint video content is produced, and the produced VRT is supplied to a content reproduction apparatus. The plural viewpoint videos which configure the retained multi viewpoint video content are broadcasted, and the plural viewpoint videos which configure the retained multi viewpoint video content are delivered through a network. 
         [0016]    A content reproduction apparatus according to a second embodiment of the present disclosure is a content reproduction apparatus for reproducing a multi viewpoint video content formed from a plurality of viewpoint videos imaged simultaneously by a plurality of different video cameras, including an acquisition section adapted to acquire a VRT including acquisition destination information of the viewpoint videos which configure the multi viewpoint video content, an inputting section adapted to input a viewpoint moving operation from a user therethrough, a reception section adapted to receive, from among the plural viewpoint videos which configure the multi viewpoint video content, the plurality of viewpoint videos corresponding to the inputted viewpoint moving operation based on the VRT, and a production section adapted to produce a video corresponding to the viewpoint moving operation based on the received plural viewpoint videos. 
         [0017]    The acquired VRT may further include a viewpoint string type representative of a relationship between an adjacent viewpoint video imaged adjacent each of the viewpoint videos which configure the video content and the viewpoint video. 
         [0018]    The viewpoint string type may be Panorama, Theater, Parallel or Separated. 
         [0019]    The production section may connect, in the case where the viewpoint string type of the received plural viewpoint videos is Panorama or Parallel, the received plural viewpoint videos to each other and cuts out a predetermined region to produce a video corresponding to the viewpoint moving operation, but produce, in the case where the viewpoint string type of the received plural viewpoint videos is Theater, a video corresponding to the viewpoint moving operation by an interpolation process using the received plural viewpoint videos. 
         [0020]    The reception section may receive, from among the plural viewpoint videos which configure the multi viewpoint video content, the plural viewpoint videos corresponding to the inputted viewpoint moving operation from within a broadcasting signal or acquire the plural viewpoint videos corresponding to the inputted viewpoint moving operation from a content transmission apparatus through a communication network. 
         [0021]    The inputting section may be formed from a viewpoint moving button included in the acquired VRT and corresponding to a viewpoint string type of an adjacent viewpoint video imaged adjacent each viewpoint video which configures the multi viewpoint video content. 
         [0022]    A content reproduction method according to the second embodiment of the present disclosure is a content reproduction method for a content reproduction apparatus which reproduces a multi viewpoint video content formed from a plurality of viewpoint videos imaged simultaneously by a plurality of different video cameras, including acquiring a VRT including acquisition destination information of the viewpoint videos which configure the multi viewpoint video content, inputting a viewpoint moving operation from a user therethrough, receiving, from among the plural viewpoint videos which configure the multi viewpoint video content, a plurality of viewpoint videos corresponding to the inputted viewpoint moving operation based on the VRT, and producing a video corresponding to the viewpoint moving operation based on the received plural viewpoint videos, carried out by the content reproduction apparatus. 
         [0023]    A program according to the second embodiment of the present disclosure is a program for causing a computer, which reproduces a multi viewpoint video content formed from a plurality of viewpoint videos imaged simultaneously by a plurality of different video cameras, to function as an acquisition section adapted to acquire a VRT including acquisition destination information of the viewpoint videos which configure the multi viewpoint video content, an inputting section adapted to input a viewpoint moving operation from a user therethrough, a reception section adapted to receive, from among the plural viewpoint videos which configure the multi viewpoint video content, a plurality of viewpoint videos corresponding to the inputted viewpoint moving operation based on the VRT, and a production section adapted to produce a video corresponding to the viewpoint moving operation based on the received plural viewpoint videos. 
         [0024]    In the second embodiment of the present disclosure, a VRT including acquisition destination information of viewpoint videos which configure a multi viewpoint video content is acquired, and a viewpoint moving operation is inputted from a user. Then, from among the plural viewpoint videos which configure the multi viewpoint video content, a plurality of viewpoint videos corresponding to the inputted viewpoint moving operation are received based on the VRT. Then, a video corresponding to the viewpoint moving operation is produced based on the received plural viewpoint videos. 
         [0025]    A content delivery system according to a third embodiment of the present disclosure is a content delivery system which includes a content transmission apparatus and a content reproduction apparatus, wherein the content transmission apparatus includes a retaining section adapted to retain a multi viewpoint video content formed from a plurality of viewpoint videos imaged simultaneously by a plurality of different video cameras, a production section adapted to produce a VRT including acquisition destination information of the viewpoint videos which configure the multi viewpoint video content, a supplying section adapted to supply the produced VRT to the content reproduction apparatus, a broadcasting section adapted to broadcast one or plural ones of the viewpoint videos which configure the retained multi viewpoint video content, and a delivery section adapted to deliver one or plural ones of the viewpoint videos which configure the retained multi viewpoint video content through a network, and the content reproduction apparatus includes an acquisition section adapted to acquire the VRT, an inputting section adapted to input a viewpoint moving operation from a user therethrough, a reception section adapted to receive, from among the plural viewpoint videos which configure the multi viewpoint video content, a plurality of the viewpoint videos corresponding to the inputted viewpoint moving operation based on the VRT, and a production section adapted to produce a video corresponding to the viewpoint moving operation based on the received plural viewpoint videos. 
         [0026]    In the third embodiment of the present disclosure, by the content transmission apparatus, a VRT including acquisition destination information of viewpoint videos which configure a multi viewpoint video content is produced, and the produced VRT is supplied to a content reproduction apparatus. Further, the plural viewpoint videos which configure the retained multi viewpoint video content are broadcasted, and the plural viewpoint videos which configure the retained multi viewpoint video content are delivered through a network. On the other hand, by the content reproduction apparatus, the VRT is acquired, and a viewpoint moving operation is inputted from a user. Further, from among the plural viewpoint videos which configure the multi viewpoint video content, a plurality of viewpoint videos corresponding to the inputted viewpoint moving operation are received based on the VRT. Then, a video corresponding to the viewpoint moving operation is produced based on the received plural viewpoint videos. 
         [0027]    With the first embodiment of the present disclosure, a video content which can be viewed in a state which it is imaged from an arbitrary viewpoint can be supplied to the reception side. 
         [0028]    With the second embodiment of the present disclosure, a video in a state in which it is imaged from an arbitrary viewpoint can be viewed. 
         [0029]    With the third embodiment of the present disclosure, a viewer can view a video in a state in which it is imaged from a viewpoint determined arbitrarily by the user. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is a view illustrating View Relation Type=1 (Panorama); 
           [0031]      FIG. 2  is a view illustrating a state in which a plurality of multi viewpoint videos, which configure a video content of Panorama, in a horizontal direction; 
           [0032]      FIG. 3  is a view illustrating View Relation Type=2 (Theater); 
           [0033]      FIG. 4  is a view illustrating View Relation Type=3 (Parallel); 
           [0034]      FIG. 5  is a view illustrating View Relation Type=4 (Separated); 
           [0035]      FIG. 6  is a block diagram showing an example of a configuration of a multi viewpoint video content viewing system to which the present disclosure is applied; 
           [0036]      FIG. 7  is a view illustrating a transmission timing of a VRT in the case where multi viewpoint videos are prepared over a full period of a video content; 
           [0037]      FIG. 8  is a view illustrating a transmission timing of a VRT in the case where multi viewpoint videos are prepared over part of a period of a video content; 
           [0038]      FIG. 9  is a view illustrating an example of reference information for acquiring a VRT; 
           [0039]      FIG. 10  is a view illustrating an example of a description of reference information; 
           [0040]      FIG. 11  is a view illustrating an example of a VRT; 
           [0041]      FIG. 12  is a view illustrating an example of a description of a VRT; 
           [0042]      FIG. 13  is a block diagram showing an example of a configuration of a reception apparatus; 
           [0043]      FIG. 14  is a flow chart illustrating a multi viewpoint video reception process; 
           [0044]      FIG. 15  is a view showing an example of a viewpoint moving button; 
           [0045]      FIGS. 16A to 16E  are views illustrating a screen transition in response to an operation of the viewpoint moving button; and 
           [0046]      FIG. 17  is a block diagram showing an example of a configuration of a computer. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0047]    In the following, the best mode (hereinafter referred to as embodiment) for carrying out the present disclosure is described in detail with reference to the drawings. 
       [Outline of the Multi Viewpoint Video Content Viewing System] 
       [0048]    An outline of a multi viewpoint video content viewing system of an embodiment of the present disclosure is described. According to the multi viewpoint video content viewing system, one video content is configured from a plurality of viewpoint videos imaged from a plurality of different camera positions, and on the reception side, an arbitrary range is cut out from each multi viewpoint video or a plurality of viewpoint videos are connected to each other or else interpolation is carried out so that a video in a state in which it is imaged from an arbitrary viewpoint can be viewed. A plurality of viewpoint videos which configure a multi viewpoint video content need not necessarily be same in resolution or coding format. 
         [0049]    It is to be noted that a multi viewpoint video content may be configured from a plurality of viewpoint videos over an entire period or may be configured from a plurality of viewpoint videos over only part of a period. 
         [0050]    A multi viewpoint video content formed from a plurality of viewpoint videos is retained on the transmission side, and for example, one viewpoint video which represents the multi viewpoint video content and is obtained by imaging an object to be imaged from the front from among a plurality of viewpoint videos which configure the multi viewpoint video content is determined as a default multi viewpoint video (entry). The viewpoint videos are broadcasted or delivered through individually different transmission lines (Broadcast Stream in television broadcasting, Internet Stream in network delivery). 
         [0051]    Relationships of a plurality of multi viewpoint videos which configure a multi viewpoint video content are classified into four different viewpoint string types of View Relation Type=1 (Panorama), View Relation Type=2 (Theater), View Relation Type=3 (Parallel) and View Relation Type=4 (Separated). 
         [0052]      FIG. 1  illustrates a situation upon imaging of a multi viewpoint video content formed from viewpoint strings of View Relation Type=1 (Panorama). In this instance, the multi viewpoint video content is obtained by disposing a plurality of video cameras at the same camera position such that they simultaneously pick up videos in different directions from one another. In the case of  FIG. 1 , by equally dividing the full circumference of 360° into eight segments and simultaneously picking up videos from the same camera positions C 0  to C 7 , viewpoint strings of viewpoint videos V 0  to V 7  of View Relation Type=1 (Panorama) are obtained. 
         [0053]    It is to be noted that, in the case where a video content is configured from viewpoint strings of Panorama, viewpoint strings for the full circumference of 360° need not necessarily be prepared. For example, a video content may be configured from viewpoint strings for one half circumference of 180° centered at the same camera position. Also the number of video cameras to be used for imaging is optional. If a smaller number of video cameras are used to increase the imaging angle of view per one video camera, then the execution frequency of a process of connecting two viewpoints on the reception side can be reduced. On the contrary, if a greater number of video cameras are used to reduce the imaging angle of view per one video camera, then picture quality deterioration such as distortion which may occur with an interpolation video can be suppressed. 
         [0054]      FIG. 2  illustrates a state in which the viewpoint strings V 0  to V 7  of Panorama which configure a video content are connected to each other in a horizontal direction. 
         [0055]    On the reception side, not only it is possible to select and view one of the viewpoint strings V 0  to V 7  but also it is possible to designate a picture frame extending over the two viewpoint strings V 2  and V 3  to view the video content. For example, in the case where a viewing picture frame which occupies only the viewpoint string V 4  is designated as shown in  FIG. 2 , only the viewpoint string V 4  is received and decoded. On the other hand, in the case where a viewing picture frame extending over the viewpoint strings V 2  and V 3  is designated, the viewpoint strings V 2  and V 3  are received and decoded and then a viewing picture frame is cut out. 
         [0056]      FIG. 3  illustrates a situation upon imaging of a multi viewpoint video content formed from viewpoint strings of View Relation Type=2 (Theater). In this instance, the multi viewpoint video content is obtained by providing a plurality of camera positions (viewpoints) on a circumference surrounding an object to be imaged such that videos of the object to be imaged are imaged simultaneously from the individual camera positions. In the case of  FIG. 3 , nine camera positions C 0  to C 8  are provided on a circumference surrounding an object to be imaged, and by carrying out imaging simultaneously from the camera positions C 0  to C 8 , viewpoint strings V 0  to V 8  of Theater are obtained. 
         [0057]    On the reception side, not only it is possible to view one of the viewpoint strings V 0  to V 8  imaged from the camera positions C 0  to C 8  different from one other on the same circumference, but also it is possible to produce videos in a state in which they are imaged from arbitrary positions different from the camera positions C 0  to C 8  on the same circumference by interpolation and view the video content. For example, in order to view a video in a state in which it is imaged from between the camera position C 2  and the camera position C 4 , the viewpoint videos V 2  and V 4  are received and decoded and a desired video is produced by an interpolation process using the viewpoint videos V 2  and V 4 . 
         [0058]      FIG. 4  illustrates a situation upon imaging of a multi viewpoint video content formed from viewpoint strings of View Relation Type=3 (Parallel). In this instance, the multi viewpoint video content is obtained by providing a plurality of camera positions (viewpoints) on a straight line opposing to an object to be imaged such that imaging is carried out simultaneously such that the imaging directions from the camera positions may be parallel to each other. In the case of  FIG. 4 , five camera positions C 0  to C 4  are provided on a straight line, and by carrying out imaging simultaneously from the camera positions C 0  to C 4 , viewpoint strings V 0  to V 4  of Parallel are obtained. 
         [0059]    On the reception side, not only it is possible to view one of the viewpoint strings V 0  to V 4  imaged from the camera positions C 0  to C 4  different from one another on the straight line, but also it is possible to produce video signals in a state in which they are imaged from arbitrary positions different from the camera positions C 0  to C 4  on the same straight line by interpolation and view the multi viewpoint video content. For example, in order to view a video in a state in which it is imaged from between the camera position C 1  and the camera position C 2 , the multi viewpoint videos V 1  and V 2  are received and decoded, and a desired video is produced by an interpolation process using the multi viewpoint videos V 1  and V 2 . 
         [0060]      FIG. 5  illustrates a situation upon imaging of a multi viewpoint video content formed from viewpoint strings of View Relation Type=4 (Separated). In this instance, the multi viewpoint video content is obtained by carrying out imaging of an object to be imaged from camera positions which are provided discretely without any regularity from the other camera positions. In the case of  FIG. 5 , from among five camera positions C 0 , C 1 , C 2 , C 10  and C 20 , the camera positions C 0 , C 1  and C 2  are disposed on the same circumference while the camera position C 10  is disposed upwardly of the camera position C 0  and the camera position C 20  is provided discretely without any regularity. Therefore, the viewpoint string type of the viewpoint strings V 10  and V 20  imaged from the camera positions C 10  and C 20  becomes Separated. 
         [0061]    It is to be noted that one multi viewpoint video content may be configured such that a plurality of viewpoint strings of different viewpoint string types are used mixedly. 
       [Example of the Configuration of the Multi Viewpoint Video Content Viewing System] 
       [0062]    Now, an example of a configuration of the multi viewpoint video content viewing system of the embodiment of the present disclosure is described. 
         [0063]      FIG. 6  shows an example of a configuration of the multi viewpoint video content viewing system of the embodiment of the present disclosure. 
         [0064]    This multi viewpoint video content viewing system  10  is configured from a transmission apparatus  20 , and reception apparatus  30 - 1  to  30 - n  connected to the transmission apparatus  20  through the Internet  11 . In the following description, where there is no necessity to individually distinguish the reception apparatus  30 - 1  to  30 - n  from one another, each of them is referred to simply as reception apparatus  30 . 
         [0065]    The transmission apparatus  20  includes a content retaining section  21 , a VRT production section  22 , a broadcasting section  23 , and a transmission section  24 . 
         [0066]    In the content retaining section  21 , a multi viewpoint video content configured from a plurality of viewpoint videos is retained. The VRT production section  22  produces a VRT (View Relation Table) necessary for the reception side to receive the multipoint videos, and outputs the VRT to the broadcasting section  23  or the transmission section  24 . 
         [0067]    The VRT includes information of viewpoint string types of a plurality of viewpoint videos which configure the multi viewpoint video content, an acquisition destination URL (URL of Broadcast Stream or Internet Stream) and so forth. It is to be noted that details of the VRT are hereinafter described with reference to  FIGS. 7 to 12 . 
         [0068]    The broadcasting section  23  reads out a predetermined one (for example, a default (entry) viewpoint video or the like) of a plurality of viewpoint videos retained in the content retaining section  21  and configuring a multi viewpoint video content, and broadcasts the read out predetermined viewpoint video as Broadcast Stream. In other words, the broadcasting section  23  broadcasts the predetermined viewpoint video as a television program through a broadcasting network  12 . Further, the broadcasting section  23  places the produced VRT into a predetermined position of the broadcasting signal and broadcasts the broadcasting signal. 
         [0069]    The transmission section  24  reads out a predetermined one (for example, one imaged from a representative camera position such as a viewpoint video other than the default (entry) viewpoint video) of a plurality of viewpoint videos retained in the content retaining section  21  and configuring a multi viewpoint video content, and delivers the predetermined viewpoint video as Internet Stream through the Internet  11 . Further, in accordance with a request from a reception apparatus  30 - i , the transmission section  24  transmits the produced VRT to the reception apparatus  30 - i  of the request source through the Internet  11 . 
         [0070]    It is to be noted that all viewpoint videos which configure the multi viewpoint video content may be broadcast as Broadcast Stream through the broadcasting network  12 . On the contrary, all viewpoint videos which configure the multi viewpoint video content may be delivered as Internet Stream through the Internet  11 . Or else, all or some of viewpoint videos which configure the multi viewpoint video content may be supplied in a state in which they are recorded on a storage medium such as a BD (blu-ray disc) to the reception side. 
       [VRT] 
       [0071]      FIG. 7  illustrates a transmission timing of a VRT in the case where the entire period of the multi viewpoint video content is configured from a plurality of viewpoint videos. 
         [0072]    In this instance, one VRT is prepared for the video content. This VRT may be supplied to the reception side before starting of broadcasting of the video content. In particular, reference information including the VRT or an acquisition destination of the VRT may be described in the EIT (Event Information Table) or the PMT (Program Map Table) of the television broadcasting signal. 
         [0073]    It is to be noted that, in the case where all viewpoint videos which configure the multi viewpoint video content are delivered through the Internet  11 , reference information including the VRT and an acquisition destination of the VRT may be conveyed as a kind of a meta file acquired before the video content is reproduced like, for example, CAD or ERI (Entry Resource Information) to the reception side. 
         [0074]      FIG. 8  illustrates a transmission timing of a VRT in the case where part of a period of a video content is configured from multi viewpoint videos, or in other words, a plurality of viewpoint videos. 
         [0075]    In this instance, a VRT is prepared for each of two periods (hereinafter referred to also as multi viewpoint segments) within which a multi viewpoint video is configured from a plurality of viewpoint videos. Each VRT may be supplied to the reception side before the starting timing of the multi viewpoint segment. In particular, reference information including an acquisition destination of the VRT corresponding to each segment may be described in the PMT of the television broadcasting signal. 
         [0076]    It is to be noted that, in the case where all viewpoint videos which configure the multi viewpoint video content are delivered through the Internet  11 , reference information including the VRT and an acquisition destination of the VRT may be conveyed as a kind of a meta file (for example, CAD or ERI) acquired before the video content is reproduced to the reception side. 
         [0077]      FIG. 9  illustrates an example of reference information including an acquisition destination of a VRT to be supplied to the reception side, and  FIG. 10  illustrates an example of a particular description of reference information. 
         [0078]    Multi-viewpoints are provided by a number equal to the number of multi viewpoint segments in one video content. For example, in the case of  FIG. 8 , two Multi-viewpoints are described. 
         [0079]    In Multi-viewpoints, three elements of @startNPI, @endNPT and @info are provided. In @startNPT, a start time position of the multi viewpoint segment is described in NPT (Normal Play Time). In @endNPT, an end time position of the multi viewpoint segment is described in NPT. In @info, a URL indicative of an acquisition destination of the corresponding VRT is described. 
         [0080]      FIG. 11  illustrates an example of a VRT, and  FIG. 12  illustrates an example of a description of a VRT corresponding to a video content imaged in the situation illustrated in  FIG. 5 . 
         [0081]    A View_object element is information relating to each viewpoint video which configures the multi viewpoint video content, and a number of View_object elements equal to the number of viewpoints are described. For View_object, seven attributes of id, name, cut, format, resolution_h, resolution_v, and location are provided. 
         [0082]    In the id attribute of View_object, identification information of the pertaining viewpoint in the multi viewpoint video is described. In the name attribute, a name of the pertaining viewpoint video is described. In the cut attribute, whether or not partial cutting out from the pertaining viewpoint video is permitted is described. In the format attribute, a coding format of the pertaining viewpoint video is described. In the resolution_h attribute, a resolution of the pertaining viewpoint video in the horizontal direction is described. In the resolution_v attribute, a resolution of the pertaining viewpoint video in the vertical direction is described. In @location, an acquisition destination URL of the pertaining viewpoint video is described. 
         [0083]    Further, in the View_object element, a neighbor_view element representative of information regarding a viewpoint video imaged at a camera position adjacent the camera position at which the pertaining viewpoint video corresponding to View_object is imaged is described as a child element. For the neighbor_view element, four attributes of an id attribute, a type attribute, a direction attribute and a distance attribute are provided. 
         [0084]    In the id attribute of the neighbor_view element, identification information of a viewpoint video (hereinafter referred to as adjacent viewpoint video) imaged at a camera position adjacent the camera position at which the viewpoint video corresponding to the View_object element of the parent element is imaged is described. In the type attribute, a viewpoint string type between adjacent viewpoints is described. In the direction attribute, a direction of the camera position at which an adjacent viewpoint video is imaged with respect to the camera position at which the pertaining multi viewpoint video corresponding to the View_object element is imaged is described. In the distance attribute, a distance or an angle of the camera position at which an adjacent viewpoint video is imaged with respect to the camera position at which the pertaining viewpoint video corresponding to the View_object element is imaged is described. 
       [Example of the Configuration of the Reception Apparatus  30 ] 
       [0085]      FIG. 13  shows an example of a configuration of the reception apparatus  30 . The reception apparatus  30  includes an operation inputting section  31 , a control section  32 , a tuner  33 , a demultiplexing (DEMUX) section  34 , video decoders  35 - 1  and  35 - 2 , audio decoders  36 - 1  and  36 - 2 , a video processing section  37 , an audio processing section  38 , a communication interface (I/F)  39 , a VRT analysis section  40 , streaming reception sections  41 - 1  and  41 - 2 , and a synchronism controlling section  42 . 
         [0086]    The operation inputting section  31  is formed, for example, from a remote controller, a reception section therefor (both not shown) and so forth, and accepts an operation of a user and notifies the control section  32  of the operation. In particular, the operation inputting section  31  accepts an operation of a user for selecting a video content, designating a position or a size of a picture frame of the video content or designating a viewpoint (camera position), and notifies the control section  32  of the operation. 
         [0087]    The control section  32  controls the components of the reception apparatus  30  in response to an operation of the user inputted using the operation inputting section  31 . The tuner  33  receives a broadcasting signal (Broadcast Stream) of a default (entry) viewpoint video from among television broadcasting signals broadcasted through the broadcasting network  12  and outputs the received streaming data to the demultiplexing section  34 . 
         [0088]    The streaming reception sections  41 - 1  and  41 - 2  receive the streaming data (Internet Stream) of multi viewpoint video from the transmission apparatus  20  via the communication interface  39  and the Internet  11  and output the received streaming data to the demultiplexing section  34 . 
         [0089]    The demultiplexing section  34  separates a VRT or reference signal for acquiring a VRT included in the PMT, EIT or the like from within a broadcasting signal inputted from the tuner  33  and supplies the VRT or the reference signal to the VRT analysis section  40 . Further, the demultiplexing section  34  separates, from a broadcasting signal inputted from the tuner  33  and streaming data inputted from the streaming reception sections  41 , video coded data and audio coded data. It is to be noted that it is assumed that the demultiplexing section  34  can process at least two systems of streaming data at the same time. The separate video coded data are inputted to the video decoder  35 - 1  or  35 - 2  while the separated audio coded data are inputted to the audio decoder  36 - 1  or  36 - 2 . 
         [0090]    The video decoders  35 - 1  and  35 - 2  decode video coded data inputted thereto and output video signals of different viewpoint videos obtained by the decoding to the video processing section  37 . The audio decoders  36 - 1  and  36 - 2  decode audio coded data inputted thereto and output audio signals at individual viewpoints obtained by the decoding to the audio processing section  38 . 
         [0091]    The video processing section  37  connects two video signals (which correspond to two viewpoint videos whose camera positions are adjacent each other) inputted from the video decoders  35 - 1  and  35 - 2  and cuts out a predetermined region, produces a video corresponding to an arbitrary viewpoint by interpolation, or superposes a video of an operation button, which serves as a user interface, to produce a video signal to be presented to the user. The video processing section  37  then outputs the produced video signal to a monitor (not shown) on the succeeding stage. The audio processing section  38  synthesizes two audio signals (which correspond to two viewpoint videos whose camera positions are adjacent each other) inputted from the audio decoders  36 - 1  and  36 - 2  to produce an audio signal to be presented to the user and outputs the audio signal to the monitor (not shown) on the succeeding stage. 
         [0092]    The communication I/F  39  establishes connection to the transmission apparatus  20  through the Internet  11 . 
         [0093]    The VRT analysis section  40  acquires, in the case where reference information for acquiring a VRT is supplied thereto from the demultiplexing section  34 , a VRT from the transmission apparatus  20  through the communication I/F  39  and the Internet  11  in accordance with the reference information. Further, the VRT analysis section  40  analyzes a VRT supplied thereto from the demultiplexing section  34  or acquired by the VRT analysis section  40  itself and outputs a result of the analysis to the control section  32 . 
         [0094]    The synchronism controlling section  42  controls the video decoders  35 - 1  and  35 - 2 , audio decoders  36 - 1  and  36 - 2 , video processing section  37 , audio processing section  38  and streaming reception sections  41 - 1  and  41 - 2  so that operation timings of them may be synchronized with each other. 
       Description of Operation 
       [0095]      FIG. 14  is a flow chart illustrating a multi viewpoint video reception process by the reception apparatus  30 . 
         [0096]    As a prerequisite, it is assumed that the reception apparatus  30  is receiving a default viewpoint video of a video content broadcasted as a television program through the broadcasting network  12 . 
         [0097]    At step S 1 , the VRT analysis section  40  acquires and analyzes reference information of a VRT and the VRT supplied thereto from the demultiplexing section  34  or produced by itself and outputs a result of the analysis to the control section  32 . At step S 2 , the control section  32  decides whether or not the progressing position of the video content being received is a multi viewpoint segment. 
         [0098]    In the case where it is decided that the progressing position of the video content being received is not a multi viewpoint segment, the processing is advanced to step S 3 . At step S 3 , the video processing section  37  erases, if a viewpoint moving button is displayed on a video of the video content being received, the display of the viewpoint moving button under the control of the control section  32 . In the case where the viewpoint moving button is not displayed, the video processing section  37  carries out nothing. Thereafter, the processing returns to step S 2 , and the processes beginning with step S 2  are repeated. 
         [0099]    In the case where it is decided at step S 2  that the progressing position of the video content being reproduced is a multi viewpoint segment, the processing is advanced to step S 4 . At step S 4 , the video processing section  37  causes, if a viewpoint moving button is not displayed on the video of the video content being received, the viewpoint moving button to be displayed under the control of the control section  32 . In the case where a viewpoint moving button is displayed, the display is maintained. 
         [0100]    Here, the viewpoint moving button displayed on a video of a video content is described.  FIG. 15  shows an example of 12 kinds of viewpoint moving buttons. It is to be noted that which one of a plurality of viewpoint moving buttons should be displayed is decided based on the type attribute and the direction attribute of the neighbor_view element included in the View_object element of the viewpoint video being received when the VRT is referred to. In the case where the viewpoint string type is Panorama, Theater or Parallel, the amount of movement of the viewpoint is determined in response to a depression time period or a number of times of depression of the corresponding viewpoint moving button. 
         [0101]    Reference is returned to  FIG. 14 . At step S 5 , the control section  32  decides based on an input from the operation inputting section  31  whether or not a viewpoint moving button is operated by the user. In the case where a viewpoint moving button is not operated, the processing returns to step S 2  and the processes at the steps beginning with step S 2  are repeated. 
         [0102]    In the case where it is decided at step S 5  that a viewpoint moving button is operated, the processing is advanced to step S 6 . At step S 6 , the control section  32  decides based on the operated viewpoint moving button whether or not the viewpoint string type to the viewpoint video of the destination of the movement is Separated. In the case where the viewpoint string type is Separated, the processing is advanced to step S 7 . At step S 7 , the control section  32  controls the components to receive and decode the viewpoint video of the destination of the movement and output a resulting video signal to the succeeding stage. Thereafter, the processing returns to step S 2  and the processes at the steps beginning with step S 2  are repeated. 
         [0103]    In the case where it is decided at step S 6  that the viewpoint string type to the viewpoint video of the destination of the movement is not Separated, the processing is advanced to step S 8 . At step S 8 , the control section  32  calculates the amount of the movement of the viewpoint based on the depression time or the number of times of depression of the viewpoint moving button to determine the viewpoint position of the destination of the movement. 
         [0104]    At step S 9 , the control section  32  decides based on the VRT whether or not there exists a viewpoint video actually imaged at the viewpoint position of the destination of the movement to determine whether or not the viewpoint position of the destination of the movement requires interpolation. 
         [0105]    In the case where there exists a viewpoint video imaged actually at the viewpoint position of the destination of the movement and the viewpoint position of the destination of the movement does not require interpolation, the processing is advanced to step S 10 . At step S 10 , the control section  32  controls the components to receive and decode the viewpoint video corresponding to the viewpoint position of the destination of the movement and output a resulting video signal to the succeeding stage. Thereafter, the processing returns to step S 2  and the processes at the steps beginning with step S 2  are repeated. 
         [0106]    In the case where it is decided at step S 9  that there exists no viewpoint video imaged actually at the viewpoint position of the destination of the movement and the viewpoint position of the destination of the movement requires interpolation, the processing advances to step S 11 . At step S 11 , the control section  32  controls the components to receive and decode two multi viewpoint videos imaged at actual camera positions across the viewpoint position of the destination of the movement and output resulting two videos to the video processing section  37 . At step S 12 , the video processing section  37  produces, based on the viewpoint string type and the viewpoint positions of the two video signals inputted thereto, a video in a state in which it is imaged at the viewpoint position, and outputs a resulting video signal to the succeeding stage so as to be displayed. 
         [0107]    In particular, in the case where, for example, the viewpoint string type of two video signals is Panorama or Parallel, the two video signals are connected to each other in a horizontal direction and a picture frame corresponding to the viewpoint position is cut out. On the other hand, in the case where, for example, the viewpoint string type of the two video signals is Theater, a video corresponding to the viewpoint position is produced by an interpolation process based on the two video signals. It is to be noted that, although an arbitrary technique can be used for the interpolation process, the technique proposed as Japanese Patent Application No. 2010-274808 by the application of the present application may be applied. 
         [0108]    Thereafter, the processing returns to step S 2  and the processes at the steps beginning with step S 2  are repeated. The description of the multi viewpoint video reception process ends therewith. 
         [0109]      FIGS. 16A to 16E  illustrate an example of a screen transition in response to operations of the viewpoint moving buttons by the user. 
         [0110]    If, for example, when such a default (entry) multi viewpoint video as shown in  FIG. 16A  is being received, the progressing position of the video content comes to a multi viewpoint segment, then viewpoint moving buttons are displayed on the default (entry) multi viewpoint video as shown in  FIG. 16B . In the case of  FIG. 16B , viewpoint moving buttons whose viewpoint string type is Theater and which can individually move the viewpoint position toward the left side and the right side are displayed. 
         [0111]    If the user operates the viewpoint moving button on the left side on the screen of  FIG. 16B , then the video on the screen is changed to a state in which the viewpoint position is moved to the left side on a concentric circle. On the screen after the change, a viewpoint moving button whose viewpoint string type is Theater and which moves the viewpoint position toward the right side, that is, which can restore the state of  FIG. 16B , is displayed. On the contrary, if the user operates the viewpoint moving button on the right side on the screen of  FIG. 16B , then the video on the screen changes to a state in which the viewpoint position is moved toward the right side on a concentric circle. On the screen after the change, a viewpoint moving button whose viewpoint string type is Theater and which can move the viewpoint position toward the left side, that is, which can restore the state of  FIG. 16B , is displayed. 
         [0112]    Thereafter, if the progressing position of the video content comes out of the multi viewpoint segment, then the display screen of the viewpoint moving button is erased as shown in  FIG. 16E . 
         [0113]    With the multi viewpoint video content viewing system described above, for example, the following scenarios can be implemented. 
         [0114]    Scenario 1 
         [0115]    The full circumference of 360° around a four-wheel drive car, which runs on a savanna in Kenya, is imaged as a multi viewpoint video of the viewpoint string type Panorama from on the four-wheel drive car and is broadcasted. A viewer of this program can change the video to that of an arbitrary direction to discover a wild animal existing therearound. 
         [0116]    Scenario 2 
         [0117]    A video of a show played in a circular theater in Las Vegas is imaged as a multi viewpoint video, whose viewpoint string type is Theater, by video cameras disposed at fixed intervals along a central passageway provided circularly among seats and is broadcasted. A viewer of this program can view a video in a state in which the stage is seen from an arbitrary position of the central passageway. 
         [0118]    Incidentally, while the series of processes described above can be executed by hardware, it may otherwise be executed by software. In the case where the series of processes is executed by software, a program which constructs the software is installed from a program recording medium into a computer incorporated in hardware for exclusive use, a personal computer, for example, for universal use which can execute various functions by installing various programs, and so forth. 
         [0119]      FIG. 17  is a block diagram showing an example of a hardware configuration of a computer which executes the series of processes described hereinabove in accordance with a program. 
         [0120]    In this computer  100 , a CPU (Central Processing Unit)  101 , a ROM (Read Only Memory)  102  and a RAM (Random Access Memory)  103  are connected to each other by a bus  104 . 
         [0121]    Further, an input/output interface  105  is connected to the bus  104 . An inputting section  106  including a keyboard, a mouse, a microphone and so forth, an outputting section  107  including a display unit, a speaker and so forth, a storage section  108  formed from a hard disk, a nonvolatile memory, or the like, a communication section  109  formed from a network interface or the like, and a drive  110  for driving a removable medium  111  such as a magnetic disk, an optical disk, a magneto-optical disk or a semiconductor memory are connected to the input/output interface  105 . 
         [0122]    In the computer  100  configured in such a manner as described above, the CPU  101  loads a program stored, for example, in the storage section  108  into the RAM  103  through the input/output interface  105  and the bus  104  and executes the program to carry out the series of processes described above. 
         [0123]    It is to be noted that the program to be executed by the computer may be a program of the type by which the processes are carried out in a time series in the order as described in the present specification or a program of the type by which the processes are executed in parallel or executed individually at necessary timings such as when the process is called. 
         [0124]    Further, the program may be of the type which is processed by a single computer or may be of the type which is carried out by distributed processing by a plurality of computers. Further, the program may be transferred to and executed by a computer at a remote place. 
         [0125]    Further, in the present specification, the term system is used to represent an entire apparatus composed of a plurality of apparatus. 
         [0126]    It is to be noted that the embodiment of the present disclosure is not limited to the embodiment described hereinabove but can be altered in various manners without departing from the subject matter of the present disclosure.