JP2016015705A - Video distribution apparatus and picture reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video distribution apparatus that improves video quality at a portion to which a viewer pays attention and allows proper selection of a display screen while suppressing a frequency band for distributing a video when a whole-sky video or a cylindrical panorama video is interactively viewed.SOLUTION: A video distribution apparatus that distributes video data of a video reproducing region which is a specified part of a region among entire video data to a video reproducing apparatus, as entire video data, when handling a panorama video obtained by expanding a whole-sky video by an equidistance cylindrical projection mapping method or a cylindrical type panorama video, for maintaining continuity of a boundary of the panorama video, a panorama video to an outside of a boundary part of which a video of a predetermined size is given is generated, and video data of a video reproduction region cut out from the whole-sky video compatible panorama video or the cylindrical type compatible panorama video is distributed in accordance with a distribution request from the video reproduction apparatus.

Description

  The present invention relates to a video distribution device that performs interactive video distribution of an all-sky video or a cylindrical panoramic video, and a video playback device that performs video playback.

  In recent years, research has been conducted on technologies that allow viewers to freely view high-definition images with resolutions that greatly exceed high-definition quality, such as 4K, 8K, and huge panoramic images, while freely manipulating them at desired positions and sizes. . For example, Non-Patent Document 1 targets a huge panoramic image with a resolution exceeding the high-vision quality. In Non-Patent Document 1, a high-spec personal computer is assumed as a playback terminal for playing a part of a high-definition video. In addition, Non-Patent Document 2 uses a low-spec tablet or smartphone for high-definition. A technique for enabling a part of the video to be reproduced is also being studied.

  In Non-Patent Document 2, a large panoramic video is first divided into a plurality of resolutions, and then the video of each resolution is further divided into views in which rectangles of a certain size are shifted little by little. Is going on. FIG. 8 is a diagram illustrating a configuration example of a view for a high-definition video. As shown in FIG. 8, the resolution is divided into, for example, three levels of high resolution, medium resolution, and low resolution, and a view in which a rectangle of a certain size is slightly shifted from each video is configured. In FIG. 8, (1) to (3), (11), (12), and (20) are views. Non-Patent Document 2 describes an international standard H.264. According to the H.264 / MVC (Multi View Coding) format, the video encoded data of each view is collected to form one panoramic video stream.

  In addition, when a viewer views a huge panoramic video while freely operating a desired position and size, the viewer is viewing an area (display area) from which the viewer is viewing. ) And the lowest resolution view including the entire panoramic video are read and decoded. Then, after superimposing the decoding results of the video with the optimum resolution and the video with the lowest resolution, the image is clipped from the image and displayed on the display device.

  If the position or size of the display image changes as a result of the viewer's operation, change the position of the view with the optimal resolution to be read following this (when the position changes), or change the optimal resolution (change in size) By decoding these, the video can be continuously displayed without interruption in time and space.

  Next, with reference to FIG. 9, the video stream distribution operation from the distribution server to the low-spec terminal will be described. FIG. 9 is a diagram illustrating a video stream distribution operation. First, the client terminal requests distribution of an appropriate high-resolution view (view A in FIG. 9) including a video display area and a lowest-resolution view (view B in FIG. 9) (FIG. 9 (i)). )). Subsequently, the distribution server distributes view A and view B requested from the client terminal (FIG. 9 (ii)).

  In response to this, the client terminal simultaneously decodes the appropriate high-resolution view (view A) and the lowest-resolution view (view B) (decodes two views) to obtain a superimposed video (FIG. 9 (iii) )). The client terminal clips the video of the position and size requested by the viewer from the obtained video and displays it on the screen (FIG. 9 (iv)).

  After the processing operation, when the position and size requested by the viewer (video display area) are changed, the appropriate high-resolution view is changed and the above-described processing operation is repeated.

  Next, the configuration of the distribution server and the client terminal shown in FIG. 9 will be described with reference to FIG. FIG. 10 is a block diagram illustrating configurations of the distribution server 10 and the client terminal 20. In the high-definition video partial distribution system including the distribution server 10 and the client terminal 20 shown in FIG. 10, video information and audio information are transmitted from the video / audio information output unit 11 in real time for live video and the like, and video / audio encoding is performed. The encoding is performed in the unit 12. The video information and audio information are file information stored in advance in the video / audio information output unit 11.

  The video / audio encoding unit 12 divides and encodes the video information into a plurality of videos (for example, as shown in FIG. 8). At this time, the positions of the plurality of images are output to the plurality of image position information transmission unit 13. Further, as the multiple video position information, for example, in the case of division as shown in FIG. 8, the size of the video (if there are multiple resolutions, the video size for each resolution), the size of the view, and the left and right of the view The video position can be determined by an arrangement in which the shift amount and the vertical shift amount are used as video position information, and a raster scan is performed in advance from the upper left to assign a number.

  The video information and audio information encoded offline (non-real-time) are stored in the video / audio information storage unit 14 and are encoded in the reception unit 24 on the client terminal 20 side via the transmission unit 15. Video information and encoded audio information are transmitted. Thereafter, the video / audio decoding unit 25 decodes the encoded video information and the encoded audio information. The video / audio reproduction unit 26 reproduces video and audio so that the viewer can view the video / audio.

  As a feature of this system, the multiple video position information receiving unit 21 of the client terminal 20 transmits the multiple video position information to the screen operation control unit 22, and a gaze area (= display area) that the viewer is watching is determined. When the change is made, the changed gaze area of the viewer is extracted from the plurality of video position information, and this is transmitted to the gaze area request unit 23, which is further transmitted to the gaze area control unit 16 on the distribution server 10 side. Send. As a result, the distribution server 10 outputs a plurality of videos of the optimal resolution video and the lowest resolution video suitable for the gaze area on the client terminal 20 side to the transmission unit 15, thereby matching the gaze area of the viewer. The encoded video information thus transmitted is transmitted, and the changed viewer's gaze area can be viewed.

Hideaki Kimata, Shinya Shimizu, Yutaka Kunita, Megumi Isogai, and Yoshimitsu Ohtani: `` Panorama video coding for user-driven interactive video application '', IEEE International Symposium on Consumer Electronics (ISCE) 2009, 2009. Hideaki Kimata, Daisuke Ochi, Akio Kameda, Hajime Noto, Katsuhiko Fukazawa, and Akira Kojima, "Mobile and Multi-device Interactive Panorama Video Distribution System," IEEE GCCE 2012, 2012.

  By the way, there are the following problems when the conventional technique disclosed in Non-Patent Document 2 is applied as a panoramic image developed by an equirectangular projection based on an all-round image or a cylindrical panoramic image.

  When a panoramic video is distributed, a correspondence table (see FIG. 11) for associating the panoramic video view with the equirectangular cylindrical projection from the viewing position of the all-sky video is required. FIG. 11 is a diagram illustrating an example of a correspondence table that associates the viewing position of the all-sky video with the view number on the panoramic video. By referring to this correspondence table, if the depression angle α and the azimuth angle β indicating the viewing position of the all-sky video are specified, the corresponding view number on the panoramic video can be specified.

  However, as the resolution of the all-sky video increases, the angle (α, β) interval representing the viewing position decreases, and the resolution of the panoramic video developed by equirectangular projection increases and the view increases. The size of the correspondence table tends to be very large. The same applies to a cylindrical panoramic image.

  Further, in the conventional technique, the center of gravity (x, y) (pixel position in the panoramic image) of the two-dimensional viewing area calculated from the viewing area of the user represented by the planar rectangular area, and the center of gravity of each view Compared the positions of and requested the closest view. Furthermore, a panoramic image having a resolution specified by the content designer is selected based on the size of the viewing area of the user.

  However, the positions of the pixels of the all-sky video are three-dimensionally arranged, and the center of gravity of the two-dimensional viewing area (x, y as in the prior art) is used to obtain the center of gravity of the viewing area of the all-sky video. ) Cannot be expressed, and the technology for designating the view in the prior art cannot be easily diverted as it is. It is also conceivable that the viewing area of the user is projected once onto a panoramic image based on the equirectangular projection, but in this case, the calculation cost is increased by the amount of projection conversion compared to the prior art (first problem). . The same applies to a cylindrical panoramic image.

  Furthermore, since the panoramic image by the equirectangular projection of the all-sky image or the boundary portion of the cylindrical panoramic image becomes a three-dimensional expression, the continuity as the junction of the left and right boundary portions is maintained. There is a need. However, in the conventional panoramic video, there is a case where an appropriate view cannot be selected because there is no continuity at the boundary (second problem).

  The present invention has been made in view of such circumstances, and when viewing an all-sky video or a cylindrical panoramic video interactively, the viewer's attention is suppressed while suppressing the bandwidth for video distribution. An object of the present invention is to provide a video distribution device and a video playback device capable of improving the video quality of a portion.

  The present invention is a video distribution device for distributing video data in a video playback area, which is a specified partial area of the entire video data, to a video playback device, and When dealing with panoramic images developed by equirectangular projection, a panorama for all-sky video, in which a predetermined size of video is added to the outside of the boundary to maintain the continuity of the boundary of the developed panoramic image A video is generated, and the video data in the video playback area cut out from the panoramic video corresponding to the all-sky video is distributed in response to a distribution request from the video reproduction device.

  The present invention is characterized in that the image of a predetermined size provided outside the boundary is an image for a maximum viewing angle at each resolution.

  The present invention is characterized in that the video of a predetermined size given to the outside of the boundary portion is a video of a horizontal size of the view.

  The present invention relates to a video distribution device that distributes video data in a video playback area, which is a specified partial area of the entire video data, to the video playback device, and the entire video data is a cylindrical panoramic video. In order to maintain the continuity of the boundary portion of the expanded panoramic image, a cylindrical-type panoramic image in which a predetermined size of the image is applied to the outside of the boundary portion is generated. The video data in the video playback area cut out from the cylindrical panoramic video is distributed in response to a distribution request from the video playback device.

  The present invention is characterized in that the image of a predetermined size provided outside the boundary is an image for a maximum viewing angle at each resolution.

  The present invention is characterized in that the video of a predetermined size given to the outside of the boundary portion is a video of a horizontal size of the view.

  The present invention is a video playback device that receives and plays back video data from the video distribution device, and selects a panoramic video having a predetermined resolution from a plurality of resolutions according to the viewing angle of the video playback area, and the depression angle and direction The video playback area to be played back is selected from the position information of the panoramic video expressed by a corner, and the video delivery apparatus is requested to distribute the video data in the selected video playback area. .

  The present invention is a video playback apparatus that receives and plays back video data from the video distribution apparatus, and selects a panoramic video having a predetermined resolution from a plurality of resolutions according to the viewing angle of the video playback area, and the height and direction The video playback area to be played back is selected from the position information of the panoramic video expressed by a corner, and the video delivery apparatus is requested to distribute the video data in the selected video playback area. .

  According to the present invention, when viewing an all-sky video or a cylindrical panoramic video interactively, it is possible to improve the video quality of the viewer's attention while suppressing the bandwidth for video distribution. .

It is a block diagram which shows the structure of one Embodiment of this invention. It is explanatory drawing which shows the example of matching of the view of a panoramic image by the equirectangular projection of a whole sky image. It is explanatory drawing which shows the example of matching of the view of a cylindrical panoramic image. It is explanatory drawing which shows the example of the process with respect to the boundary part to equirectangular projection or a cylindrical panoramic image. It is explanatory drawing which shows the largest viewing angle (gamma) in angle (beta) direction. It is explanatory drawing which shows the example of the coordinate transformation in equirectangular projection. It is explanatory drawing which shows the example of the coordinate transformation in a cylindrical panoramic image. It is a figure which shows the structural example of the view with respect to a high definition image | video. It is a figure which shows the delivery operation | movement of a video stream. 2 is a block diagram illustrating configurations of a distribution server 10 and a client terminal 20. FIG. It is a figure which shows an example of the corresponding | compatible table which matches the viewing position of all the sky images, and the view number on a panoramic image.

<First Embodiment>
Hereinafter, a video distribution device and a video reproduction device according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. In this figure, the same parts as those of the conventional apparatus shown in FIG. The apparatus shown in this figure is different from the conventional apparatus in that a video / audio encoding unit 120, a gaze area control unit 160, a gaze area request unit 230, and a video / audio reproduction unit 260 are provided.

  Next, the operation of the apparatus shown in FIG. 1 will be described. First, the distribution server 10 (video distribution apparatus) will be described with respect to an operation for encoding video. First, the video / audio encoding unit 120 generates an all-sky video as a panoramic video by equirectangular projection and as a panoramic video having a plurality of resolutions as shown in FIG. When the panoramic image is converted into the panoramic image by the equirectangular projection, the “content designer” specifies the resolution of the panoramic image. For example, if dot-by-dot display is performed near the equator of the all-sky image, if the maximum viewing angle is 90 degrees on the equator of the all-sky image, and 640 pixels, the image is expanded four times (90 × 4 = 360 degrees), which means 2560 pixels (horizontal direction).

  Following this, the vertical direction is halved to 180 degrees, so the number of pixels is halved to 1280 pixels. At this time, the origin of the all-sky image is the center of the sphere shown in the upper left of FIG. FIG. 2 is an explanatory diagram showing an example of panoramic video view correspondence using an equirectangular projection of the whole sky video. The position information for specifying the viewing area of the all-sky video uses an angle α and an angle β as shown in the lower left of FIG. The angle α corresponds to the depression angle. The angle β corresponds to the azimuth. The upper right of FIG. 2 is a panoramic image of a certain resolution developed by equidistant cylindrical projection, with the vertical axis representing the angle α (0 to 180 °) and the horizontal axis representing the angle β (0 to 360 °). The view is selected by selecting the view with the center of gravity close to the angle (α, β).

  In the case of a cylindrical panoramic video, the video / audio encoding unit 120 generates a cylindrical panoramic video as a panoramic video having a plurality of resolutions as shown in FIG. At this time, the origin of the center of the cylinder is as shown in FIG. “Height” represents the distance from the upper side of the cylinder. FIG. 3 is an explanatory diagram illustrating an example of the association of cylindrical panoramic video views.

  The position information for specifying the viewing area of the cylindrical panoramic image uses an angle β and a height h as shown on the left side of FIG. The right side of FIG. 2 is a panoramic image with a certain resolution developed with the vertical axis representing height h (0 to H (maximum height)) and the horizontal axis representing angle β (0 to 360 °). The view is selected by selecting a view with a center of gravity close to (h, β).

  Next, the video / audio encoding unit 120 adds the maximum viewing angle to the panoramic video as shown in FIG. FIG. 4 is an explanatory diagram illustrating an example of processing for a boundary portion to equirectangular projection or a panoramic image for a cylindrical shape. As shown in the upper part of FIG. 4, when a view with the center of gravity closest to (α, β) or (h, β) is selected in the developed panoramic video, there may be no corresponding view. As shown in FIG. 4, when the position specified by (α, β) is close to the right end of the panoramic video, the view protrudes from the boundary portion of the panoramic video. This is because the left end and the right end of the panoramic image are originally connected, but since the expansion is performed, the left end and the right end are cut off.

  Therefore, as shown in the lower part of FIG. 4, an area having a predetermined number of pixels from the right end of the panoramic image (area A1 shown in FIG. 4) is an area outside the left end of the panoramic picture (area A2 shown in FIG. 4). Add as Further, an area having a predetermined number of pixels from the left end of the panoramic video (area A3 shown in FIG. 4) is added as an area outside the right end of the panoramic video (area A4 shown in FIG. 4). This makes it possible to select the view with the center of gravity closest to (α, β) or (h, β). In the description, the outer region is given to the left end and the right end of the panoramic image, but the region may be given to the outside of either one (left end or right end).

In order to support multiple resolutions, panoramic video with a certain resolution by equirectangular cylindrical projection is set to X (horizontal) x Y (vertical) pixels on the celestial image (α = 90 degrees). If the maximum viewing angle in the angle β direction at γ is (degrees), the size of the video that needs to be given in the horizontal direction is
X × γ / 360 pixels. FIG. 5 is an explanatory diagram showing the maximum viewing angle γ in the angle β direction. This is because by adding a video for the maximum viewing angle to a panoramic video of a certain resolution, β = 0 degrees or near β = 360 degrees (around the left and right edges of a panoramic video of a certain resolution) at any resolution. This is because the display area corresponding to the maximum viewing angle can always be included in a certain view in consideration of the case where is designated as the viewing position.

For example, when the panoramic image size of the highest resolution by the equirectangular projection is 2560 (horizontal) × 1280 (vertical) pixels and the maximum viewing angle is 90 degrees,
It is necessary to apply 2560 × 90 (degrees) / 360 (degrees) = 640 pixels in the horizontal direction.

On the other hand, if the size of the panoramic video with a certain resolution is 1280 × 640 pixels,
1280 × 90 (degrees) / 360 (degrees) = 320 pixels may be given in the horizontal direction, and depending on the size of the panoramic video of a certain resolution, the pixels to be given in the horizontal direction have their respective resolutions and maximum viewing angles. Video is added according to

  Note that the lowest resolution panoramic image includes all information of the equirectangular projection of all the omnidirectional images or the cylindrical panoramic image, so the horizontal direction as shown in FIG. Video is not necessary. The same applies to a cylindrical panoramic image.

  After that, the video / audio encoding unit 120 divides the panoramic video of each resolution that has been completed up to the processing shown in FIG. 4 into views having an overlap of a certain size as shown in FIG. H. It is encoded / multiplexed by H.264 / MVC or the like.

  Next, an operation in which the client terminal 20 (video playback device) performs video playback will be described. When the gaze area request unit 230 requests the gaze area, in the case of an all-sky video, the gaze area request unit 230 designates the viewing position with respect to the distribution server 10 using the angles α and β as shown in FIG.

  In response to this, the gaze area control unit 160 identifies a high-resolution view with a close center of gravity from the angles α and β shown in FIG. Note that there may be a plurality of corresponding high-resolution views. In addition, each low-resolution view including the entire panoramic video is specified, and the video / audio information storage unit 14 transmits these views from the transmission unit 15 to the client terminal 20.

Then, the video / audio reproduction unit 260 generates and reproduces an all-around video from low-resolution and high-resolution views by performing mutual coordinate conversion. This makes it possible to view the all-sky video. Mutual coordinate conversion is performed as follows, as shown in FIG. FIG. 6 is an explanatory diagram showing an example of coordinate transformation in equirectangular projection. In the case of a panoramic image, when the coordinate of the pixel in the horizontal direction of the panoramic image is u and the coordinate of the pixel in the vertical direction is v,
β = 360 × u / W
α = 180 × v / H
Holds. Here, W is the video size in the horizontal direction, and H is the video size in the vertical direction.
Therefore, the coordinates u and v of the pixels on the panoramic image are
u = W × β / 360
v = H × α / 180
Can be obtained.

  On the other hand, in the case of a cylindrical panoramic video, the gaze area requesting unit 230 designates the viewing position to the distribution server 10 by the height h and the angle β as shown in FIG.

  In response to this, the gaze area control unit 160 specifies a high-resolution view with a close center of gravity from the height h and the angle β shown in FIG. Note that there may be a plurality of corresponding high-resolution views. In addition, each low-resolution view including the entire panoramic video is specified, and the video / audio information storage unit 14 transmits these views from the transmission unit 15 to the client terminal 20.

  Then, the video / audio reproduction unit 260 generates and reproduces an all-around video from low-resolution and high-resolution views by performing mutual coordinate conversion. This makes it possible to view a cylindrical panoramic video. Mutual coordinate conversion is performed as follows, as shown in FIG. FIG. 7 is an explanatory diagram illustrating an example of coordinate conversion in a cylindrical panoramic image.

  The height h (maximum value: H) of the cylindrical panoramic image matches the height h (maximum value: H) of the original panoramic image with the highest resolution. However, because of the concept of multiple resolutions, other panoramic images with a certain resolution are reduced in comparison with the original panoramic images. Therefore, the height h2 of the panoramic image with another certain resolution is higher than that of the cylindrical panoramic image. It cannot be used as it is.

Therefore, when the panoramic image height h2 of a certain resolution is set to the maximum value H2,
The height h of the cylindrical panoramic image is expressed as follows.
h = h2 × H / H2

Conversely, when obtaining the height h2 of the panoramic image of a certain resolution from the height h of the cylindrical panoramic image,
h2 = h × H2 / H
Need to be converted.

Similarly, β = 360 × u / W2 in the horizontal direction
Can be expressed by
u = W2 × β / 360
And convert.

  When viewing, when the user's viewing angle is narrow (in the case of viewing angle when viewing the video), a higher resolution panoramic video view is adopted, and the viewing angle is wide (viewing with the video pulled down). In the case of a viewing angle), a lower-resolution panoramic video view is adopted. A specific resolution can be included in β, for example, β + 1000 for resolution 1 and β + 2000 for resolution 2.

Second Embodiment
Next, a video distribution device and a video reproduction device according to a second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, as shown in FIG. 4, the horizontal size of the view is added to the panoramic video. Even when a plurality of resolutions are considered, if the horizontal size of the view is Vx, the size of the video that needs to be given in the horizontal direction of the panoramic video of a certain resolution is Vx pixels.

  As shown in FIG. 2, a view with a close center of gravity is specified from the viewing positions indicated by the angles α and β, but at any resolution, β = 0 degrees or near β = 360 degrees (a panoramic image having a certain resolution). In consideration of the case where the viewing position is designated at the left end or the right end of FIG. 4, in order not to generate a view lacking the image as shown in FIG. It is.

  Note that the lowest resolution panoramic image contains all the information of the equirectangular projection of all omnidirectional images or the cylindrical panoramic image, so the image in the horizontal direction as shown in FIG. Is not necessary. The same applies to a cylindrical panoramic image.

  After that, the panoramic video of each resolution completed up to the processing shown in FIG. 4 is divided into views having an overlap of a certain size, as shown in FIG. It is encoded / multiplexed by H.264 / MVC or the like. This processing is performed by the video / audio encoding unit 120 shown in FIG.

  On the other hand, on the client terminal 20 side, in the case of the all-sky video, the viewing position is designated to the distribution server 10 by the angles α and β as shown in FIG. This process is performed by the gaze area request unit 230 shown in FIG.

  The gaze area control unit 160 illustrated in FIG. 1 specifies a high-resolution view with a close center of gravity from the angles α and β in FIG. Note that there may be a plurality of corresponding high-resolution views. In addition, each low-resolution view including the entire panoramic video is specified, and these views are transmitted from the transmission unit 15.

  Furthermore, in the video / audio reproduction unit 260 shown in FIG. 1, the mutual coordinate conversion can be viewed by generating an all-round video from low-resolution and high-resolution views as shown in FIG. .

  Similarly, in the case of a cylindrical panoramic image, the viewing position is designated to the distribution server 10 by the height h and the angle β as shown in FIG. This process is performed by the gaze area request unit 230 in FIG.

  The gaze area control unit 160 shown in FIG. 1 specifies a high-resolution view with a close center of gravity from the height h and the angle β in FIG. Note that there may be a plurality of corresponding high-resolution views. In addition, each low-resolution view including the entire panoramic video is specified, and these views are transmitted from the transmission unit 15.

  Further, in the video / audio reproduction unit 260 shown in FIG. 1, the mutual coordinate conversion can be viewed by generating a cylindrical panoramic video from low-resolution and high-resolution views as shown in FIG. Become. Note that the height h (maximum value: H) of the cylindrical panoramic image and the height h (maximum value: H) of the original panoramic image having the highest resolution coincide with each other. However, because of the concept of multiple resolutions, a panoramic image with a certain other resolution is reduced in comparison with the original panoramic image, so that the height h2 of the other panoramic image with a certain resolution is h of the cylindrical panoramic image. Cannot be used as is.

Therefore, when the maximum value of the panoramic video height h2 of a certain resolution is H2, the height h of the cylindrical panoramic video is expressed as follows.
h = h2 × H / H2

Conversely, when obtaining the height h2 of the panoramic image of a certain resolution from the height h of the cylindrical panoramic image,
h2 = h × H2 / H
Need to be converted.

  When viewing, when the user's viewing angle is narrow (in the case of viewing angle when viewing the video), a higher resolution panoramic video view is adopted, and the viewing angle is wide (viewing with the video pulled down). In the case of viewing angle), a lower-resolution panoramic video view is adopted. A specific resolution can be included in β, for example, β + 1000 for resolution 1 and β + 2000 for resolution 2.

  In addition, in order to maintain the continuity of the boundary part of the developed panoramic video, the size of the video to be given outside the boundary part is not limited to the maximum viewing angle for each resolution and the horizontal size of the view, Any size may be used.

  In this way, as the viewing area of the user of the all-sky video, the correspondence table between each pixel of the panoramic video and the view by the equirectangular projection of the whole-sky video is not created, and the angles α and β of the whole-sky video are By using only two parameters, the view closest to the center of gravity of each view of the panoramic image by the equirectangular projection is distributed as a high-resolution view. At the same time, a low-resolution view including the entire panoramic image by the equirectangular projection of the whole sky image is also distributed. Further, in the case of a cylindrical panoramic image, the same distribution is performed using only two parameters of height h and angle β. With this configuration, the first problem can be solved.

  In addition, a panoramic image based on the equirectangular projection of the whole sky image, or a predetermined size image is added to the boundary of the cylindrical panoramic image to maintain continuity, and this is added to the new sky image. By encoding as equirectangular panoramic video or cylindrical panoramic video, the conventional discontinuity at the boundary is avoided. In addition, as an example of the size of the video to be provided in order to maintain continuity, a size according to the maximum viewing angle of the user viewing area can be applied. As another example, the horizontal size of the view can be applied. With this configuration, the second problem can be solved.

  As described above, when generating a panoramic image from a panoramic image that greatly exceeds the high-definition quality using equirectangular cylindrical projection, the entire celestial image (low resolution) is distributed in consideration of interactivity. To the all-sky video playback client, and then only a portion of the part that the user is paying attention to is distributed at high resolution. In addition to the all-sky image, a cylindrical panoramic image may be used. As a result, when the part that the user is paying attention to is moved, a low-resolution video is displayed for a while. You can watch the video. In addition, it is possible to distribute in a smaller band than the band when the whole sky image is distributed with high resolution video quality.

  In order to achieve this, this embodiment introduces the concept of “multiple resolution” and “view” to panoramic video based on equirectangular projection of all-sky video or cylindrical panoramic video, thereby reducing the bandwidth of video distribution. Interactive video viewing is possible while suppressing this. In addition, when generating panoramic images using the equirectangular cylindrical projection of all-sky images, or cylindrical panoramic images, the image for the maximum viewing angle or the horizontal size of the view has continuity at the boundary. Thus, it is possible to select an appropriate view of the panoramic image for the all-sky image / cylindrical type that could not be solved by the conventional concept of the panoramic image view.

  According to this configuration, when viewing an all-sky video or a cylindrical panoramic video interactively, the resolution (video quality) of the portion of interest of the user is improved while suppressing the bandwidth for video distribution. Interactive video viewing is possible. Furthermore, there was a problem that an appropriate view could not be selected at the boundary only by converting the panoramic image to the panoramic image by the equirectangular projection. However, the panoramic image by the equirectangular projection or the cylindrical panoramic image was not selected. Appropriate views can be selected by adding a part of the video.

  The distribution server and client terminal in the above-described embodiment may be realized by a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in the computer system. It may be realized using hardware such as PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Therefore, additions, omissions, substitutions, and other modifications of the components may be made without departing from the technical idea and scope of the present invention.

  When viewing all-sky video or cylindrical panoramic video interactively, while suppressing the bandwidth for video distribution, improve the video quality of the viewer's attention and make appropriate view selection Can be applied to essential applications.

  DESCRIPTION OF SYMBOLS 10 ... Distribution server (video distribution apparatus), 11 ... Video / audio information output unit, 120 ... Video / audio encoding unit, 13 ... Multiple video position information transmission unit, 14 ... Video / Audio information storage unit, 15... Transmission unit, 160... Gaze area control unit, 20... Client terminal (video reproduction device), 21. Operation control unit, 230 ... gaze area request unit, 24 ... reception unit, 25 ... video / audio decoding unit, 260 ... video / audio reproduction unit

Claims (8)

A video distribution device that distributes video data of a video playback area that is a specified partial area of the entire video data to a video playback device,
In order to maintain the continuity of the boundary portion of the developed panoramic image when handling the panoramic image obtained by developing the whole sky image by the equirectangular cylindrical projection as the whole image data, the predetermined size image is converted to the boundary portion. A panoramic image corresponding to the all-sky video provided outside the image and generating the video data in the video playback area cut out from the panoramic video corresponding to the all-sky video in response to a distribution request from the video playback device. A video distribution apparatus characterized by that.   The video distribution apparatus according to claim 1, wherein the video of a predetermined size provided outside the boundary is a video for a maximum viewing angle at each resolution.   The video distribution apparatus according to claim 1, wherein the video of a predetermined size provided outside the boundary is a video of a horizontal size of a view. A video distribution device that distributes video data of a video playback area that is a specified partial area of the entire video data to a video playback device,
When handling a panoramic video obtained by developing a cylindrical panoramic video as the whole video data, a predetermined size video is added to the outside of the boundary to maintain the continuity of the developed panoramic video boundary. And generating the cylindrical panoramic video and distributing the video data in the video playback area cut out from the cylindrical panoramic video in response to a distribution request from the video playback device. .   The video distribution apparatus according to claim 4, wherein the video of a predetermined size provided outside the boundary portion is a video for a maximum viewing angle at each resolution.   The video distribution apparatus according to claim 4, wherein the video of a predetermined size provided outside the boundary is a video of a horizontal size of a view. A video reproduction device for receiving and reproducing video data from the video distribution device according to any one of claims 1 to 3,
Select a panoramic video of a predetermined resolution from multiple resolutions according to the viewing angle of the video playback area, and select and select the video playback area to be played back from the position information of the panoramic video expressed by the depression angle and azimuth A video playback apparatus that requests the video distribution apparatus to distribute the video data in the video playback area. A video reproduction device that receives and reproduces video data from the video distribution device according to any one of claims 4 to 6,
Select a panoramic video of a predetermined resolution from multiple resolutions according to the viewing angle of the video playback area, select the video playback area to be played back from the position information of the panoramic video expressed in height and azimuth, and select A video playback apparatus that requests the video distribution apparatus to distribute the video data in the video playback area.

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