Title of Invention: 3D video reproduction device, non-transitory computer-readable medium, 3D display device, 3D imaging device, and 3D video reproduction method Abstract: A stereoscopic video reproduction device comprising: a first acquisition unit; a second acquisition unit configured to acquire a display size of a stereoscopic display of output destination; a decision unit configured to compare the acquired display size of the stereoscopic display and the plurality of intra-interval maximum display sizes and decides whether the display size of the stereoscopic display is larger than the plurality of intra-interval maximum display sizes; a selection unit configured to select, from the viewpoint images at N viewpoints, two viewpoint images corresponding to an intra-interval maximum display size which the decision unit decides to be equal to or smaller than the display size of the stereoscopic display among the plurality of intra-interval maximum display sizes; and an output unit configured to output a stereoscopic video formed with the two viewpoint images selected by the selection unit when outputting the acquired stereoscopic video to the stereoscopic display. Detailed Description: Part general_description_paragraphs: Part CROSS-REFERENCE TO RELATED APPLICATIONS: This application is a continuation application and claims the priority benefit under 35 U.S.C. §120 of PCT Application No. PCT/JP2011/077760 filed on Dec. 1, 2011 which application designates the U.S., and also claims the priority benefit under 35 U.S.C. §119 of Japanese Patent Application No. 2011-022047 filed on Feb. 3, 2011, which applications are all hereby incorporated by reference in their entireties. Part BACKGROUND OF THE INVENTION: 1. Field of the Invention The present invention relates to a stereoscopic video reproduction device, a stereoscopic video reproduction program and a non-transitory computer-readable recording medium therefor, a stereoscopic display device, a stereoscopic imaging device, and a stereoscopic video reproduction method. Specifically, the present invention relates to a technique of reproducing a stereoscopic video of a stereoscopic video file in which a stereoscopic image formed with a plurality of viewpoint images is consecutively recorded in a time axis direction. 2. Description of the Related Art A stereoscopic imaging device takes images of an object in right and left viewpoints using two right and left imaging units arranged with parallax, acquires the viewpoint image for the left eye and the viewpoint image for the right eye respectively and records them in a recording medium. When these acquired right and left viewpoint images are read from the recording medium, input in a 3D display that can perform three-dimensional (3D) display, and are displayed such that the viewpoint image for the left eye and the viewpoint image for the right eye can be visually checked by right and left eyes respectively, it is possible to recognize the result as a stereoscopic video. By the way, the parallax amount between the recorded right and left viewpoint images varies depending on the change in an imaging scene, the movement of the object, the change in the zoom magnification or the like, and, meanwhile, the 3D display has various screen sizes. Therefore, in a case where reproduction display of a stereoscopic video is to be performed, there is a case where the parallax amount for the stereoscopic video is not suitable for the size of the 3D display. In such a case, there arises a problem that the pop-up amount and pop-down amount from the screen are excessive and it is not possible to recognize the stereoscopic video as a natural stereoscopic video. Japanese Patent Application Laid-Open No. 2004-180069 discloses a technique of: acquiring suitable screen size information related to the screen size suitable for reproduction of a stereoscopic image, display screen size information of a 3D display, suitable visual distance information related to the suitable distance to a display screen for an observer to view the display screen at the time of reproduction, and visual distance information related to the distance from the observer to the display screen of the 3D display, in addition to image information that can be stereoscopically viewed; setting the shift amount (offset) between the left eye image and the right eye image based on these items of information; and adjusting the stereoscopic feeling of the displayed image. It is not clear whether the stereoscopic image disclosed in Japanese Patent Application Laid-Open No. 2004-180069 is a still image or a video. In the case of a stereoscopic video, the parallax amount of right and left viewpoint images varies depending on the change in an imaging scene, the movement of an object, the change in the zoom magnification, and so on. Even if, for the sake of argument, the parallax amount of a stereoscopic video is adjusted by the technique disclosed in JAPANESE PATENT APPLICATION LAID-OPEN NO. 2004-180069 such that the stereoscopic video has a natural pop-up amount, it is considered to adjust the parallax amount in units of frames of the stereoscopic video. However, in this case, there is a problem that a feature as the stereoscopic video in which the stereoscopic feeling varies is lost and an unnatural stereoscopic video is provided. By the way, on a display screen of a 3D display, in a case where the right eye image has a parallax in the right direction with respect to the left eye image, a stereoscopic image is visually checked as an image with a larger depth than the display screen, but, when the screen size of the 3D display increases, this parallax increases too. When the parallax exceeds a man's binocular interval, binocular fusion is impossible (i.e. binocular vision is impossible). Although JAPANESE PATENT APPLICATION LAID-OPEN NO. 2004-180069 discloses acquiring a stereoscopic image in which the optimal stereoscopic degree (i.e. depth amount) is adjusted in proportion to the display screen size of the 3D display, it does not disclose adjusting the shift amount between the left eye image and the right eye image such that the above-mentioned binocular fusion is not impossible. Further, since it does not contain description related to the maximum parallax amount of the distant view side (or depth side) of a stereoscopic image either, the stereoscopic image display device disclosed in JAPANESE PATENT APPLICATION LAID-OPEN NO. 2004-180069 cannot adjust the shift amount between the left eye image and the right eye image such that the parallax does not exceed the man's binocular interval regardless of the screen size of the 3D display. The present invention is made in view of such circumstances and it is an object to provide a stereoscopic video reproduction device, a stereoscopic video reproduction program and a recording medium therefor, a stereoscopic display device, a stereoscopic imaging device and a stereoscopic video reproduction method that can reproduce a stereoscopic video with an appropriate parallax amount such that binocular fusion is possible regardless of the screen size of a stereoscopic display at the time of stereoscopically displaying a stereoscopic video read from a stereoscopic video file on the stereoscopic display with an arbitrary screen size. Part SUMMARY OF THE INVENTION: To achieve the object, a stereoscopic video reproduction device according to the present invention includes: a first acquisition unit configured to read a stereoscopic video file and acquires a stereoscopic video and attached information from the stereoscopic video file, where the stereoscopic video in which a stereoscopic image formed with viewpoint images at N (N: integer equal to or greater than 3) viewpoints is consecutively provided in a time axis direction and the attached information are recorded in the stereoscopic video file and the attached information includes a plurality of intra-interval maximum display sizes which are the largest in respective consecutive predetermined intervals in the time axis direction of each stereoscopic video and which correspond to a plurality of stereoscopic images formed with combinations of two arbitrary viewpoint images of the viewpoint images at the N viewpoints and to each of the predetermined intervals, among the maximum display sizes every frame in which binocular fusion is possible when displaying each frame of the stereoscopic video on a stereoscopic display; a second acquisition unit configured to acquire a display size of a stereoscopic display of output destination; a decision unit configured to compare the acquired display size of the stereoscopic display and the plurality of intra-interval maximum display sizes and decides whether the display size of the stereoscopic display is larger than the plurality of intra-interval maximum display sizes, for each of the plurality of intra-interval maximum display sizes; a selection unit configured to select, from the viewpoint images at the N viewpoints, two viewpoint images corresponding to an intra-interval maximum display size which the decision unit decides to be equal to or smaller than the display size of the stereoscopic display among the plurality of intra-interval maximum display sizes; and an output unit configured to output a stereoscopic video formed with the two viewpoint images selected by the selection unit when outputting the acquired stereoscopic video to the stereoscopic display. According to the present invention, viewpoint images at N viewpoints and the intra-interval maximum display sizes corresponding to a plurality of stereoscopic images formed with combinations of two arbitrary viewpoint images and to each of consecutive predetermined intervals in the time axis direction of each stereoscopic video are acquired from a stereoscopic video file, and the display size of the stereoscopic display of output destination is acquired, the acquired display size of the stereoscopic display and each intra-interval maximum display size are compared, a pair of viewpoint images at two viewpoints is selected from one or more pairs of viewpoint images at two viewpoints corresponding to the intra-interval maximum display size decided to be equal to or smaller than the display size of the stereoscopic display among each of the intra-interval maximum display sizes, and the viewpoint images are output to the stereoscopic display, so that it is possible to select and output a stereoscopic video with an appropriate parallax amount based on the attached information recorded in the stereoscopic video file. A stereoscopic video reproduction device according to the present invention includes: a first acquisition unit configured to read a stereoscopic video file and acquires a stereoscopic video and attached information from the stereoscopic video file, where the stereoscopic video in which a stereoscopic image formed with viewpoint images at N (N: integer equal to or greater than 3) viewpoints is consecutively provided in a time axis direction and the attached information are recorded in the stereoscopic video file and the attached information includes a plurality of intra-interval maximum parallax amounts which are the largest in consecutive predetermined intervals in the time axis direction of each stereoscopic video and which correspond to a plurality of stereoscopic images formed with combinations of two arbitrary viewpoint images of the viewpoint images at the N viewpoints and to each of the consecutive predetermined intervals in the time axis direction of the stereoscopic video, among maximum parallax amounts on a distant view side in each frame of each stereoscopic video; a second acquisition unit configured to acquire a display size of a stereoscopic display of output destination; a decision unit configured to decide whether a binocular fusion is possible when displaying a plurality of stereoscopic videos in the predetermined intervals corresponding to a plurality of intra-interval maximum parallax amounts, for each of the plurality of intra-interval maximum parallax amounts and each of the predetermined intervals, based on the plurality of intra-interval maximum parallax amounts acquired corresponding to every predetermined interval of the stereoscopic video, the acquired display size of the stereoscopic display and a predetermined value indicating man's binocular interval; a selection unit configured to select, from the viewpoint images at the N viewpoints, two viewpoint images corresponding to an intra-interval maximum parallax amount for which the decision unit decides that the binocular fusion is possible among the plurality of intra-interval maximum parallax amounts; and an output unit configured to output a stereoscopic video formed with the two viewpoint images selected by the selection unit when outputting the acquired stereoscopic video to the stereoscopic display. According to the present invention, viewpoint images at N viewpoints and the intra-interval maximum parallax amounts corresponding to a plurality of stereoscopic images formed with combinations of two arbitrary viewpoint images and to each of consecutive predetermined intervals in the time axis direction of each stereoscopic video are acquired from a stereoscopic video file, and the display size of the stereoscopic display of output destination is acquired, a pair of viewpoint images at two viewpoints is selected from one or more pairs of viewpoint images at two viewpoints in which binocular fusion is possible when displaying the stereoscopic video in the corresponding interval on the stereoscopic display, based on the acquired display size of the stereoscopic display, each intra-interval maximum parallax amount and a predetermined value indicating man's binocular interval, and the viewpoint images are output to the stereoscopic display, so that it is possible to select and output a stereoscopic video with an appropriate parallax amount based on the attached information recorded in the stereoscopic video file. The decision unit calculates an allowable parallax amount based on the display size of the stereoscopic display and the predetermined value indicating the man's binocular interval, and, depending on whether the plurality of intra-interval maximum parallax amounts are equal to or less than the allowable parallax amount, decides whether the binocular fusion is possible, for each of the plurality of intra-interval maximum parallax amounts and each of the predetermined intervals. In this stereoscopic video reproduction device, the decision unit includes an image shift amount calculation unit configured to calculate an image shift amount on a stereoscopic display corresponding to the intra-interval maximum parallax amount based on the acquired intra-interval maximum parallax amount and the display size of the stereoscopic display, and decides whether the binocular fusion is possible, depending on whether the calculated image shift amount exceeds the predetermined value indicating the man's binocular interval. In this stereoscopic video reproduction device, in a case where two viewpoint images in which the binocular fusion is possible are not selected by the selection unit, the output unit selects one viewpoint image of the viewpoint images at the N viewpoints and outputs the selected viewpoint image to the stereoscopic display. In this stereoscopic video reproduction device, the N viewpoints include a reference viewpoint set in advance and the selection unit preferentially selects two viewpoint images including a viewpoint image corresponding to the reference viewpoint when selecting the two viewpoint images. In this stereoscopic video reproduction device, when selecting the two viewpoint images, the selection unit selects two viewpoint images in which the intra-interval maximum display size or the intra-interval maximum parallax amount is the largest. In this stereoscopic video reproduction device, when selecting the two viewpoint images, the selection unit selects two view point images in which the intra-interval maximum display size or the intra-interval maximum parallax amount is the smallest. In this stereoscopic video reproduction device, when selecting the two viewpoint images, the selection unit preferentially selects two viewpoints including a viewpoint image near a center. In this stereoscopic video reproduction device, in a case where the viewpoint images at the N viewpoints recorded in the stereoscopic video file include a plurality of viewpoint images corresponding to an actual viewpoint and a virtual viewpoint image corresponding to a virtual viewpoint generated from the plurality of viewpoint images corresponding to the virtual viewpoint, when selecting the two viewpoint images, the selection unit preferentially selects viewpoint images at two viewpoints including the viewpoint image of the actual viewpoint. In this stereoscopic video reproduction device, the stereoscopic video file is an MPEG file in which a plurality of viewpoint images are sequentially recorded every one GOP formed with a plurality of frames, and the predetermined interval of the stereoscopic video is an interval corresponding to a predetermined number of GOPs equal to one or two, or greater than two. In this stereoscopic video reproduction device, the predetermined interval of the stereoscopic video is an interval distinguished every scene. A stereoscopic video reproduction program according to the present invention causes a computer to realize the above stereoscopic video reproduction device. A computer-readable recording medium that records this stereoscopic video reproduction program is included in the present invention too. A stereoscopic display device according to the present invention includes the above stereoscopic video reproduction device and the stereoscopic display of output destination. A stereoscopic imaging device according to the present invention includes: an imaging unit configured to acquire a stereoscopic video in which a stereoscopic image formed with a plurality of viewpoint images is consecutively provided in a time axis direction; a parallax amount calculation unit configured to calculate a parallax amount indicating a shift amount between feature points with a common feature, from a plurality of viewpoint images every frame of the acquired stereoscopic video; a maximum parallax amount acquisition unit configured to acquire a maximum parallax amount on a distant view side from the calculated parallax amount of each feature point every frame; an intra-interval maximum parallax amount acquisition unit configured to acquire an intra-interval maximum parallax amount which is the largest in every predetermined interval of the stereoscopic video, in the acquired maximum parallax amount on the distant view side; an intra-interval maximum display size acquisition unit configured to acquire an intra-interval maximum display size in which binocular fusion is possible when the stereoscopic image is displayed on a stereoscopic display every predetermined interval, based on the intra-interval maximum parallax amount acquired every predetermined interval of the stereoscopic video; a recording unit configured to generate a stereoscopic video file in which the stereoscopic video is recorded, records the stereoscopic video file in a recording medium, records the stereoscopic video in the stereoscopic video file and records the intra-interval maximum display size every predetermined interval in the stereoscopic video file as attached information; and the above stereoscopic video reproduction device, where the first acquisition unit reads the stereoscopic video file from the recording medium. A stereoscopic imaging device according to the present invention includes: an imaging unit configured to image a stereoscopic video in which a stereoscopic image formed with a plurality of viewpoint images is consecutively provided in a time axis direction; a parallax amount calculation unit configured to calculate a parallax amount indicating a shift amount between feature points with a common feature, from a plurality of viewpoint images every frame of the acquired stereoscopic video; a maximum parallax amount acquisition unit configured to acquire a maximum parallax amount on a distant view side from the calculated parallax amount of each feature point every frame; an intra-interval maximum parallax amount acquisition unit configured to acquire an intra-interval maximum parallax amount which is the largest in every predetermined interval of the stereoscopic video, in the acquired maximum parallax amount on the distant view side; a recording unit configured to generate a stereoscopic video file in which the stereoscopic video is recorded, records the stereoscopic video file in a recording medium, records the stereoscopic video in the stereoscopic video file and records the intra-interval maximum parallax amount every predetermined interval in the stereoscopic video file as attached information; and the stereoscopic video reproduction device according to claim 2, where the first acquisition unit reads a stereoscopic video file from the recording medium. A stereoscopic video reproduction method according to the present invention causes a stereoscopic video reproduction device to execute: a step of reading a stereoscopic video file and acquiring a stereoscopic video and attached information from the stereoscopic video file, where the stereoscopic video in which a stereoscopic image formed with viewpoint images at N (N: integer equal to or greater than 3) viewpoints is consecutively provided in a time axis direction and the attached information are recorded in the stereoscopic video file and the attached information includes a plurality of intra-interval maximum display sizes which are the largest in consecutive predetermined intervals in the time axis direction of each stereoscopic video and which correspond to a plurality of stereoscopic images formed with combinations of two arbitrary viewpoint images of the viewpoint images at the N viewpoints and to each of the predetermined intervals, among the maximum display sizes every frame in which binocular fusion is possible when displaying each frame of the stereoscopic video on a stereoscopic display; a step of acquiring a display size of a stereoscopic display of output destination; a decision step of comparing the acquired display size of the stereoscopic display and the plurality of intra-interval maximum display sizes and deciding whether the display size of the stereoscopic display is larger than the plurality of intra-interval maximum display sizes, for each of the plurality of intra-interval maximum display sizes; a selection step of selecting, from the viewpoint images at the N viewpoints, two viewpoint images corresponding to an intra-interval maximum display size which the decision step decides to be equal to or smaller than the display size of the stereoscopic display among the plurality of intra-interval maximum display sizes; and a step of outputting a stereoscopic video formed with the two viewpoint images selected by the selection step when outputting the acquired stereoscopic video to the stereoscopic display. A stereoscopic video reproduction method according to the present invention causes a stereoscopic video reproduction device to execute: a step of reading a stereoscopic video file and acquiring a stereoscopic video and attached information from the stereoscopic video file, where the stereoscopic video in which a stereoscopic image formed with viewpoint images at N (N: integer equal to or greater than 3) viewpoints is consecutively provided in a time axis direction and the attached information are recorded in the stereoscopic video file and the attached information includes a plurality of intra-interval maximum parallax amounts which are the largest in consecutive predetermined intervals in the time axis direction of each stereoscopic video and which correspond to a plurality of stereoscopic images formed with combinations of two arbitrary viewpoint images of the viewpoint images at the N viewpoints and to each of the consecutive predetermined intervals in the time axis direction of the stereoscopic video, among maximum parallax amounts on a distant view side in each frame of the stereoscopic video; a step of acquiring a display size of a stereoscopic display of output destination; a decision step of deciding whether a binocular fusion is possible when displaying a plurality of stereoscopic videos in the predetermined intervals corresponding to a plurality of intra-interval maximum parallax amounts on the stereoscopic display, for each of the plurality of intra-interval maximum parallax amounts and each of the predetermined intervals, based on the plurality of intra-interval maximum parallax amounts acquired corresponding to every predetermined interval of the stereoscopic video, the acquired display size of the stereoscopic display and a predetermined value indicating man's binocular interval; a selection step of selecting, from the viewpoint images at the N viewpoints, two viewpoint images corresponding to an intra-interval maximum parallax amount for which the decision step decides that the binocular fusion is possible among the plurality of intra-interval maximum parallax amounts; and a step of outputting a stereoscopic video formed with the two viewpoint images selected by the selection step when outputting the acquired stereoscopic video to the stereoscopic display. According to the present invention, viewpoint images at N (N: integer equal to or greater than 3) viewpoints and the intra-interval maximum display sizes or intra-interval maximum parallax amounts corresponding to a plurality of stereoscopic images formed with combinations of two arbitrary viewpoint images of the viewpoint images at N viewpoints and to each of consecutive predetermined intervals in the time axis direction of each stereoscopic video are acquired from a stereoscopic video file, the display size of the stereoscopic display of output destination is acquired, a pair of viewpoint images at two viewpoints is selected from one or more pairs of viewpoint images at two viewpoints in which binocular fusion is possible, based on the acquired display size of the stereoscopic display, each intra-interval maximum display size or intra-interval maximum parallax amount and a predetermined value indicating man's binocular interval, and the viewpoint images are output to the stereoscopic display, so that it is possible to select and output a stereoscopic video with an appropriate parallax amount based on the attached information recorded in the stereoscopic video file. Also, since the stereoscopic video with an appropriate parallax amount is selected and output, processing for parallax correction of the stereoscopic video is unnecessary and it is possible to reduce the load of image processing. Part DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: In the following, preferable embodiments of the present invention are explained in detail according to the accompanying drawings. Part First Embodiment of 3D Video File: A stereoscopic video file (3D video file) according to the first embodiment is explained. FIG. 1 is a diagram illustrating a state where viewpoint images (or videos) at two viewpoints (i.e. the left viewpoint and the right viewpoint) are imaged from different viewpoints with respect to an object 100 by two imaging devices 101-2 and 101-3, and FIG. 2 is a diagram typically showing a data structure of a 3D video file recording a 3D video formed with the left viewpoint and right viewpoint videos imaged in the imaging devices 101-2 and 101-3 illustrated in FIG. 1. The 3D video file illustrated in FIG. 2 is a MPEG file in conformity to the MPEG (moving picture expert group) format, and the viewpoint image at the left viewpoint and the viewpoint image at the right viewpoint are alternately coupled in units of one GOP (group of picture: in the MPEG compression, combination of several frames of video signals that are a unit at the time of compression and at the time of reproduction/edit) and formed as one file. A header area is provided in the head of an area recording the viewpoint image of each GOP, and this header area records attached information such as the image size, the aspect ratio and the frame rate. Also, in the present embodiment, as attached information, all or part of the following attached information is further recorded. GOP maximum display size (width, height, unit: mm) Assumed visual distance (distance between a viewer at the time of observing a stereoscopic video and a 3D display) (unit: mm) GOP maximum parallax amount (near view): parallax amount with respect to image width (%) GOP maximum parallax amount (distant view): parallax amount with respect to image width (%) Convergence angle, base line length and imaging unit arrangement (viewpoint number) of device that takes each viewpoint image Imaging/recording processing to record such a 3D video file is explained using the flowchart in FIG. 3. First, right and left viewpoint images for one frame in a plurality of frames of one GOP corresponding to the left viewpoint and the right viewpoint are acquired (step S11). Here, by the two imaging devices 101-2 and 101-3 as illustrated in FIG. 1, right and left viewpoint images for one frame of a 3D video subjected to 3D video imaging with respect to the object 100 are acquired. Here, it is assumed that the imaging device 101-2 has a viewpoint number 2 and the imaging device 101-3 has a viewpoint number 3. Next, a plurality of feature points are extracted from right and left viewpoint images (step S12) and the parallax amount in each feature point is calculated (step S13). Here, the parallax amount denotes the difference between the distances from the left ends of the respective viewpoint images in the corresponding feature point between the viewpoint images, and the unit is pixel. From the parallax amount in each feature point calculated in this way, the maximum parallax amount on the near view side and the maximum parallax amount on the distant view side are acquired (step S14). FIG. 4 is a diagram illustrating an example of right and left viewpoint images, (a) portion of FIG. 4 illustrates a left viewpoint image 201-2 and (b) portion of FIG. 4 illustrates a right viewpoint image 201-3. In the example of FIG. 4, the maximum parallax amount on the near view side is 213N, and feature points (i.e. maximum parallax amount positions (near view)) with this parallax amount are 211N and 212N, respectively. Also, the maximum parallax amount on the distant view side is 213F, and feature points (i.e. maximum parallax amount positions (distant view)) with this parallax amount are 211F and 212F, respectively. That is, in a case where a stereoscopic image based on these right and left viewpoint images is stereoscopically viewed, it is viewed such that the maximum parallax amount positions (near view) are the nearest and the maximum parallax amount positions (distant view) are the most distant. The ratios (%) of the maximum parallax amount 213N on the near view side and the maximum parallax amount 213F on the distant view side to the image width are the maximum parallax amount (near view) (%) and the maximum parallax amount (distant view) (%). Subsequently, it is decided whether to finish acquiring the maximum parallax amounts in all frames of one GOP (step S15), and, in a case where it is not finished (i.e. “in the case of NO”), it returns to step S11 to perform the processing in steps S11 to S14, and, in a case where it is finished (i.e. “in the case of YES”), it proceeds to step S16. In step S16, the largest maximum parallax amount among the maximum parallax amounts in all frames of one GOP is acquired as a GOP maximum parallax amount. Further, based on this GOP maximum parallax amount, the GOP maximum display size is acquired. When the parallax amount on the distant view side exceeds man's binocular interval, binocular fusion is impossible in the position of the image and it cannot be stereoscopically viewed. Therefore, according to the ratio (%) of the GOP maximum parallax amount (distant view) to the image width, the maximum display size (i.e. the GOP maximum display size) is acquired within the display size in which the parallax does not exceed the man's binocular interval. For example, it is assumed that the man's binocular interval is 50 mm, and, if the ratio of the GOP maximum parallax amount (distant view) to the image width is 10%, the maximum display width allowed for binocular vision is 500 mm. That is, in the case of a display with a width of 500 mm or less, right and left images corresponding to the GOP maximum parallax amount (distant view) are displayed without exceeding a binocular interval of 50 mm, and, as a result, the viewer can perform binocular vision. Here, in a case where a display with an aspect ratio of 16:9 is assumed, the maximum display height is 281.25 mm. Here, the man's binocular interval may be arbitrarily determined according to the target viewer. For example, when only adults are targeted, a wide value such as 65 mm may be set. For example, it is assumed that the man's binocular interval is 65 mm, and, if the ratio of the GOP maximum parallax amount (distant view) to the image width is 15%, the GOP maximum display size allowed for binocular vision is about 433 mm. Also, in a case where a 3D display with an aspect ratio of 16:9 is assumed, the height of the GOP maximum display size is about 244 mm. Also, instead of performing calculation from man's binocular interval, a table recording the maximum display size corresponding to the maximum parallax amount is prepared in advance, and, by referring to this table, the GOP maximum display size may be acquired. Next, the left viewpoint images and right viewpoint images for one GOP are respectively subjected to MPEG compression, alternately coupled as illustrated in FIG. 2 and recorded as a 3D video file, and, in the first header area of an area in which the viewpoint images in each GOP are recorded, for example, the GOP maximum display size, the GOP maximum parallax amount (distant view) (%) and the GOP maximum parallax amount (near view) (%) acquired in step S16 are recorded as attached information (step S17). Subsequently, by performing the above processing for all GOPs of the 3D video, it is possible to record the 3D video file illustrated in FIG. 2. The 3D video file recorded as above is read by a stereoscopic video reproduction device at the time when it is displayed on a 3D display. In this case, in the stereoscopic video reproduction device, by comparing the GOP maximum display size recorded in the attached information of the 3D video file and the display size of a 3D display on which it is to be displayed, it is possible to easily decide whether a binocular vision is possible. In a case where it is decided that the binocular vision is possible, the recorded 3D video may be displayed as is, and, in a case where it is decided that the binocular vision is not possible, it is possible to correct the parallax of right and left viewpoint images in the corresponding GOP using the GOP maximum display size and the GOP maximum parallax amount, and it is possible to reduce parallax correction processing in a stereoscopic video reproduction device. Here, in the present embodiment, although the GOP maximum display size is determined based on only the GOP maximum parallax amount on the distant view side, it may be determined taking into consideration the GOP maximum parallax amount on the near view side. By taking into consideration the GOP maximum parallax amount on the near view side, it is possible to determine the GOP maximum display size that enables appropriate binocular vision on not only the distant view side but also the near view side. For example, the display size in which the near-view parallax amount is equal to or less than 50 mm may be set as the GOP maximum display size. This is because, when the parallax amount on the near view side increases, the viewer feels fatigued for the binocular vision and therefore it is preferable to be equal to or less than a predetermined amount. Also, in the present embodiment, although the GOP maximum parallax amount and the GOP maximum display size are recorded as attached information in the first header area of a GOP in which these are acquired, it is not limited to this. As illustrated in FIG. 5, they may be recorded in the first header area of a GOP two GOPs before (i.e. the time for one GOP minute before). Also, as illustrated in FIG. 6, the GOP maximum parallax amounts and GOP maximum display sizes acquired from all GOPs may be collectively recorded in the first header area of the 3D video file. According to this, a stereoscopic video reproduction device that reads the 3D video file can detect in advance whether to adjust the parallax of the stereoscopic video in one GOP, and can calculate in advance the parallax amount to be adjusted. Further, in the present embodiment, although the largest GOP maximum parallax amount and GOP maximum display size in one GOP are acquired, it is not limited to this, and the intra-interval maximum parallax amount and intra-interval maximum display size in each of a predetermined number of GOPs (intervals) set in advance may be acquired and recorded as attached information with respect to the 3D video in the interval. Part Second Embodiment of 3D Video File: In the second embodiment, in a case where a 3D video scene changes as illustrated in FIG. 7, all or part of following attached information is recorded as attached information of the head of the scene. Flag indicating scene head Scene maximum display size (width, height, unit: mm) Assumed visual distance (i.e. distance between the viewer at the time of observing a stereoscopic video and a 3D display) (unit: mm) Scene maximum parallax amount (near view): parallax amount with respect to image width (%) Scene maximum parallax amount (distant view): parallax amount with respect to image width (%) Convergence angle, base line length and imaging unit arrangement (viewpoint number) of device that takes each viewpoint image Convergence angle, base line length and imaging unit arrangement (viewpoint number) of device that takes each viewpoint image Further, a flag indicating zoom-in/zoom-out and a flag indicating ON/OFF/Reset of blurring correction may be recorded as attached information. It is possible to change a scene by a scene change detection unit that detects the scene change from an acquired 3D video. For example, the detection is possible in cases where: the times of time stamps indicating the recording times are separated from each other in previous and subsequent 3D video frames; the correlation of previous and subsequent 3D video frames is checked and there is no correlation; the GOP maximum parallax amount changes over a predetermined threshold in adjacent GOPs; and the blurring correction state changes (ON->OFF, OFF->ON, Reset). Here, the scene change detection method is not limited to the above example and various methods are possible. The scene head flag denotes a flag indicating the head of each scene in a 3D video file coupling each scene of the 3D video as illustrated in FIG. 7, the scene maximum parallax amount is the parallax amount which is the largest in the 3D video in the scene, and the scene maximum display size is the maximum display size within the display size in which binocular fusion is possible at the time of displaying the scene on a stereoscopic display and which is acquired based on the scene maximum parallax amount in the scene. Also, as illustrated in FIG. 7, in the 3D video file in which each scene of the 3D video is coupled, for each scene, attached information such as the scene head flag, the scene maximum parallax amount in the scene and the scene maximum display size is recorded at the head of the scene. Here, in addition to the above information, scene length information of the scene is recorded in the attached information at the scene head. The scene length information can be expressed by the number of GOPs forming the scene. Part Third Embodiment of 3D Video File: In the first embodiment, an example has been explained using right and left viewpoint images taken from two viewpoints, the number of viewpoints for a 3D video according to the present invention is not limited to two viewpoints and viewpoint images at multiple viewpoints equal to or greater than three viewpoints is possible. FIG. 8 is a diagram illustrating a state where four imaging devices 101-1 to 101-4 take four viewpoint images at different viewpoints with respect to the object 100. Here, it is assumed that the viewpoint numbers of the imaging devices 101-1 to 101-4 are 1 to 4 in order. FIG. 9 is a diagram typically showing a data structure of a 3D video file recording viewpoint images at four viewpoints taken by these four imaging devices 101-1 to 101-4. Similar to the file illustrated in FIG. 2, this 3D video file is a MPEG file, and, regarding the viewpoint images at four viewpoints, in units of one GOP, viewpoint images (1) to (4) corresponding to viewpoint numbers 1 to 4 are sequentially and repeatedly coupled and formed as one file. Also, in the first header area of the record area in which each viewpoint image per GOP is recorded, similar to the first embodiment, attached information is recorded, such as the GOP maximum display size, the GOP maximum parallax amount, the assumed visual distance and the convergence angle, base line length and imaging unit arrangement (i.e. viewpoint number) of the device that takes each viewpoint image. Also, as for the GOP maximum display size and the GOP maximum parallax amount or the like recorded in the head of each of the viewpoint images (1) to (4), values calculated between the viewpoint image and other viewpoint images are recorded. To be more specific, regarding the GOP maximum display size and GOP maximum parallax amount with respect to viewpoint image (1), on the basis of viewpoint image (1) taken at the left end reference viewpoint as illustrated in FIG. 8, for example, the GOP maximum parallax amount calculated from a viewpoint image with the largest parallax amount (viewpoint image (4) in this case) and the GOP maximum display size and assumed visual distance acquired from this maximum parallax amount are recorded. Even regarding the convergence angle and the base line length, the convergence angle and base line length of a device that takes the same viewpoint image (viewpoint image (4) in this case) are recorded. As attached information of viewpoint image (2), for example, the GOP maximum display size, GOP maximum parallax amount, assumed visual distance, convergence angle, base line length and viewpoint number calculated from this viewpoint image (2) and viewpoint image (1) taken at the reference viewpoint are recorded. As attached information of viewpoint image (3), for example, the GOP maximum display size, GOP maximum parallax amount, assumed visual distance, convergence angle, base line length and viewpoint number calculated from this viewpoint image (3) and viewpoint image (1) taken at the reference viewpoint are recorded. As attached information of viewpoint image (4), for example, the GOP maximum display size, GOP maximum parallax amount, assumed visual distance, convergence angle, base line length and viewpoint number calculated from this viewpoint image (4) and viewpoint image (1) taken at the reference viewpoint are recorded. Thus, a 3D video file recording viewpoint images at multiple viewpoints equal to or greater than three viewpoints is read by a stereoscopic video reproduction device when it is displayed on a 3D display. In this case, in the stereoscopic video reproduction device, by comparing the GOP maximum display size per viewpoint image recorded in attached information of the 3D video file and the display size of the 3D display on which it is to be displayed, it is possible to easily decide whether a binocular vision is possible. The recording order of multiple viewpoint images is not limited to the order illustrated in FIG. 9, and recommendation images (e.g. two viewpoint images) when it is displayed on the 3D display may be recorded earlier. For example, in a case where stereoscopic display by viewpoint images (2) and (3) at the two viewpoints in the center is recommended, viewpoint images (2) and (3) may be recorded earlier and viewpoint images (1) and (4) may be subsequently recorded, and, meanwhile, in a case where stereoscopic display by viewpoint images (1) and (4) at the two viewpoints at both ends is recommended, viewpoint images (1) and (4) may be recorded earlier and viewpoint images (2) and (3) may be subsequently recorded. Part Fourth Embodiment of 3D Video File: All of the multiple viewpoint images as in the third embodiment need not be images that are actually taken, and a virtual viewpoint image corresponding to a virtual viewpoint may be included. For example, as illustrated in FIG. 10, two viewpoint images at different viewpoints (i.e. viewpoint number 1 and viewpoint number 4) with respect to the object 100 are taken by two imaging devices 101-1 and 101-4. Further, it is possible to generate viewpoint images 2 and 3 of viewpoint numbers 2 and 3 at virtual viewpoints, which are different viewpoints from viewpoint numbers 1 and 4 and which are not actually present. To generate a virtual viewpoint image, there are a method of internally dividing each pixel of a plurality of taken images and a method of generating it using a parallax map generated from a plurality of taken images and one taken image, but it is not specifically limited. In a 3D video file recording viewpoint images at multiple viewpoints including a viewpoint image at a virtual viewpoint, as attached information of first viewpoint image (1) among the viewpoint images at the multiple viewpoints, information indicating whether the viewpoint image at each viewpoint is the viewpoint image at an actual viewpoint or the viewpoint image at the virtual viewpoint, is collectively recorded (see FIG. 9). Here, it is not limited to a case where information of the actual viewpoint and the virtual viewpoint is collectively recorded as attached information of first viewpoint image (1), and, as the attached information of each of viewpoint images (1) to (4), information indicating whether it is the viewpoint image at the actual viewpoint or the viewpoint image at the virtual viewpoint may be individually recorded. This information indicating whether it is the viewpoint image at the actual viewpoint or the viewpoint image at the virtual viewpoint can be used in a case where a 3D video is displayed as a 2D video. {Appearance of Stereoscopic Imaging Device} FIG. 11A and FIG. 11B are diagrams illustrating an appearance of a stereoscopic imaging device according to the present invention, FIG. 11A is a perspective view seen from the front surface side of the stereoscopic imaging device and FIG. 11B is a rear view. This stereoscopic imaging device (i.e. compound eye camera) 10 is a digital camera that can record and reproduce 2D/3D still images and 2D/3D videos, and, as illustrated in FIGS. 11A and 11B, a shutter button 11 and a zoom button 12 are provided on the upper surface of the thin camera body having a rectangular parallelepiped shape. As illustrated in FIG. 11A, a lens barrier 13 having substantially the same width as the width in the horizontal direction of the camera body is provided in the front surface of the camera body so as to be freely moved in the vertical direction of the camera body, and, by moving this lens barrier 13 in the vertical direction between the position indicated by the alternate long and two dots lines and the position indicated by the solid lines, it is possible to open and close the front surfaces of a pair of right and left imaging optical systems 14-1 and 14-2 at the same time. Here, as the imaging optical systems 14-1 and 14-2, a zoom lens of folded optics is used. Also, in tandem with the opening and closing operation of the front surface of the lens by the lens barrier 13, it is possible to turn on or off the camera power supply. As illustrated in FIG. 11B, a liquid crystal monitor 16 for 3D is provided in the center part of the back of the camera body. The liquid crystal monitor 16 can display a plurality of parallax images (i.e. right viewpoint image and left viewpoint image) as directivity images having predetermined directivities by a parallax barrier, respectively. Also, as the liquid crystal monitor 16 for 3D, it is possible to apply the one using a lenticular lens or the one in which it is possible to individually view the right viewpoint image and the left viewpoint image by wearing dedicated glasses such as polarized glasses and liquid crystal shutter glasses. Various operation switches are provided on the right and left of the above liquid crystal monitor 16. An operation switch 18A is a switching switch to switch between the still image imaging and the video imaging, an operation switch 18B is a parallax adjustment switch to adjust the parallax amount between the right viewpoint image and the left viewpoint image, and an operation switch 18C is a switching switch to switch between the 2D imaging and the 3D imaging. Also, an operation switch 18D is a seesaw key combining a MENU/OK button and a reproduction button, an operation switch 18E is a multi-function arrow key and an operation switch 18F is a DISP/BACK key. The MENU/OK button is an operation switch combining: a function as a menu button to give an instruction to display a menu on the screen of the liquid crystal monitor 16; and a function as an OK button to give an instruction to confirm and execute selection content. The reproduction button is a button to switch from an imaging mode to a reproduction mode. The arrow key is an operation switch to input an instruction for four directions of top, bottom, right and left, to which a macro button, a flash button and a self-timer button or the like are assigned. Here, in a case where a menu is selected, the arrow key functions as a switch (i.e. cursor movement operation unit) to select an item from the menu screen or give an instruction to select various setting items from each menu. Also, the left/right key of the arrow key functions as a button for frame feeding (forward direction/backward direction feeding) in a reproduction mode. The DISP/BACK key is used at the time of switching a display format of the liquid crystal monitor 16, cancelling instruction content on the menu screen or returning to the previous operation state. Also, reference numeral “15” is a stereo microphone in FIG. 11A. {Internal Structure of Stereoscopic Imaging Device} FIG. 12 is a block diagram indicating an internal structure of the above stereoscopic imaging device 10. As illustrated in FIG. 12, this stereoscopic imaging device 10 is formed mainly of: a plurality of imaging units 20-1 and 20-2; a central processing unit (CPU) 32; an operation unit 34 including the above shutter button 11, the zoom button 12 and various operation switches; a display control unit 36; the liquid crystal monitor 16, a record control unit 38; a compression/decompression
{'bibliographic_information': "{'country': 'US', 'doc-number': '13954699', 'kind': 'B2', 'date': '20130730', 'extension': '65', 'disclaimer_text': 'This patent is subject to a terminal disclaimer.', 'invention_title': '3D video reproduction device, non-transitory computer-readable medium, 3D display device, 3D imaging device, and 3D video reproduction method'}", 'source_file': './grant/2015/ipg151208.xml', 'source_data': 'USPTO-Grant'}