Transmitting device and receiving device

Abstract

This transmission device (30, 30a), which transmits to a receiving device (40, 40a) multiple video signals imaged from different positions, is provided with: a control unit (32) which, with the video signals having been divided into multiple groups depending on the imaging position, assigns IDs for identifying the group; and a communication interface (37) which transmits to the receiving device (40, 40a) video signals to which an ID has been assigned.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Applications Nos. 2019-239564 and 2019-239570, filed on December 27, 2019, the entire disclosures of which are incorporated herein by reference. [Technical Field]

[0002] The present invention relates to a transmitting device that transmits a plurality of video signals captured from different positions, and a receiving device that receives the video signals. [Background technology]

[0003] As an extension of 360-degree video, video systems that allow users to view 360-degree video from any viewpoint are being considered. For example, Non-Patent Document 1 lists use cases such as "3D image messages" and "immersive 6DoF streaming," which involve viewpoint movement within the range of a user's head movement while seated as 3DoF+ (Degree of Freedom), or viewpoint movement within the range of a user's free movement as 6DoF.

[0004] Generally, one camera captures an image from one viewpoint. By using multiple images (multi-viewpoint images) captured by multiple cameras, it is possible to generate an image from an intermediate position between the positions where those images were captured. This is a well-known technique called viewpoint interpolation or intermediate viewpoint image generation (see, for example, Patent Document 1).

[0005] Furthermore, Non-Patent Document 2 defines OMAF (Omnidirectional Media Format) as a file format for storing 360-degree video signals from a predetermined viewpoint. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6306952 [Non-patent literature]

[0007] [Non-Patent Document 1] 3GPP TR 26.928, "3rd Generation Partnership Project; Technical Specification Group SA WG4 Extended Reality in 5G; (Release 16)", ver 0.5.0, 2019-07 [Non-patent document 2] ISO / IEC 23090-2: 2019, “Information technology - Coded representation of immersive media - Part 2: Omnidirectional media format” Summary of the Invention [Problem to be solved by the invention]

[0008] Viewpoint interpolation uses multiple video signals captured from different positions to generate a video from a desired viewpoint. Services like 6DoF, which allow users to view video from freely moving viewpoints, require capturing multiple videos from multiple points and then performing viewpoint interpolation. However, the captured video signals are independent of each other and lack information to correlate them. While OMAF can store a video signal from a fixed viewpoint, it does not support processing multiple video signals when the viewpoint is freely moved. As a result, receiving devices have no way to identify what video signals are present and how they are related, and when multiple video signals are received, there is no way to determine how to correlate them.

[0009] In view of the above circumstances, an object of the present invention is to provide a transmitting device and a receiving device that can easily identify the video signal required for viewpoint interpolation when the user changes the viewpoint position. [Means for solving the problem]

[0010] A transmitting device according to one embodiment transmits a plurality of video signals captured from different positions to a receiving device, the video signals being grouped into a plurality of groups according to the capturing positions, the transmitting device including: a control unit that assigns IDs for identifying the groups; and a communication interface that transmits the video signals to which the IDs have been assigned to the receiving device. The control unit specifies a request ID, which is an ID of a video signal corresponding to a change in a viewpoint position of a user of the receiving device; and the communication interface, if the request ID is the same as the ID of the video signal transmitted immediately before, transmits to the receiving device a plurality of video signals, from a group of video signals to which the request ID is assigned, that are required to generate a video corresponding to the viewpoint position of the user; and, if the request ID is different from the ID of the video signal transmitted immediately before, transmits to the receiving device a default video signal, from the group of video signals to which the request ID is assigned. do.

[0013] In one embodiment, the video signals may be divided into a plurality of groups in a plurality of layers according to a shooting position, and the control unit may assign group IDs to identify the groups.

[0014] In one embodiment, the first layer group among the multiple layer groups may be a group to which multiple video signals belong that are used to generate video from a viewpoint different from the shooting position in the receiving device.

[0015] In one embodiment, a second layer group among the groups in the plurality of layers may be one or more of the first layer groups to which a plurality of video signals captured in the same location belong.

[0016] In one embodiment, the video signals belonging to the first layer group transmitted by the communication interface may be compressed by predictive coding using correlation between video signals.

[0022] In one embodiment, the ID and the video signal may be stored in a file in ISO Base Media File Format.

[0023] A receiving device according to one embodiment receives a video signal transmitted by the transmitting device, the receiving device including: a control unit that decodes the video signal to generate a decoded video; and a communication interface that transmits viewpoint information indicating the viewpoint position of the user to the transmitting device; The aforementioned When the transmission device determines that the request ID is the same as the ID of the video signal transmitted immediately before, the communication interface receives from the transmission device a plurality of video signals, among the group of video signals to which the request ID is assigned, that are required to generate a video corresponding to the viewpoint position, and when the transmission device determines that the request ID is different from the ID of the video signal transmitted immediately before, the communication interface receives from the transmission device a default video signal, among the group of video signals to which the request ID is assigned. When the control unit receives the plurality of video signals, the control unit generates a video corresponding to the viewpoint position, and when the control unit receives the default video signal, the control unit decodes the default video signal. do. [Effects of the Invention]

[0025] According to the present invention, when the user changes the viewpoint position, it is possible to easily identify the video signal required for viewpoint interpolation. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a block diagram showing an example of a video transmission system according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating a first group ID according to the first embodiment. [Figure 3] FIG. 10 is a diagram illustrating a second group ID according to the first embodiment. [Figure 4] 2 is a diagram illustrating a hierarchical structure of a video signal according to the first embodiment. FIG. [Figure 5A] 3 is a diagram showing an example of the structure of a file for storing a video signal according to the first embodiment; FIG. [Figure 5B] 3 is a diagram showing an example of the structure of a file for storing a video signal according to the first embodiment; FIG. [Figure 6] FIG. 2 is a diagram showing a display example of the receiving device according to the first embodiment. [Figure 7] FIG. 3 is a sequence diagram showing an example of the operation of the video transmission system according to the first embodiment. [Figure 8] FIG. 10 is a block diagram showing an example of a video transmission system according to a second embodiment. [Figure 9] FIG. 10 is a sequence diagram showing an example of the operation of the video transmission system according to the second embodiment. [Figure 10] FIG. 10 is a block diagram showing an example of a video transmission system according to a third embodiment. [Figure 11] FIG. 11 is a sequence diagram showing an example of the operation of the video transmission system according to the third embodiment. [Figure 12] FIG. 1 is a block diagram showing a schematic configuration of a computer. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0028] First Embodiment (Video Transmission System) First, a video transmission system according to a first embodiment will be described. FIG. 1 is a diagram illustrating a video transmission system 1 according to the first embodiment, illustrating an overview of the transmission of multiple video signals captured at multiple locations. The video transmission system 1 includes multiple imaging devices (cameras) 10, multiple first transmission devices 20, a second transmission device 30, and a receiving device 40. In this specification, a "location" refers to a predetermined area set aside for a specific purpose, such as a venue, stadium, facility, or park. In this embodiment, the video transmission system 1 includes three first transmission devices 20, and the following description will be given assuming that the first transmission device 20A transmits a video signal captured at location A, the first transmission device 20B transmits a video signal captured at location B, and the first transmission device 20C transmits a video signal captured at location C.

[0029] The imaging device 10 adds metadata to a video signal captured at a predetermined position and transmits the video signal to the first transmission device 20. Here, the metadata transmitted by the imaging device 10 is position information indicating the shooting position of the imaging device 10 and may include information indicating the shooting direction. The metadata may also include distance information indicating the distance from the imaging device 10 to the photographed object.

[0030] That is, the multiple imaging devices 10A installed at location A each attach metadata to a video signal captured at a predetermined position in location A and transmit the video signal to the first transmitting device 20A. Similarly, the multiple imaging devices 10B installed at location B each attach metadata to a video signal captured at a predetermined position in location B and transmit the video signal to the first transmitting device 20B. Similarly, the multiple imaging devices 10C installed at location C each attach metadata to a video signal captured at a predetermined position in location C and transmit the video signal to the first transmitting device 20C.

[0031] The first transmitting device 20A receives video signals and metadata from multiple imaging devices 10A, assigns an ID to them, and transmits them to the second transmitting device 30. Similarly, the first transmitting device 20B receives video signals and metadata from multiple imaging devices 10B, assigns an ID to them, and transmits them to the second transmitting device 30. Similarly, the first transmitting device 20C receives video signals and metadata from multiple imaging devices 10C, assigns an ID to them, and transmits them to the second transmitting device 30.

[0032] Transmission from the imaging device 10 to the first transmitting device 20 and transmission from the first transmitting device 20 to the second transmitting device 30 can use SDI (Serial Digital Interface), IP (Internet Protocol), or the like. More specifically, when SDI is used, transmission can be performed using 12G-SDI, 3G-SDI, HD-SDI, or the like. When IP is used, transmission can be performed using RTP (Real-Time Transport Protocol) based on the SMPTE (Society of Motion Picture and Television Engineers) ST 2110 standard. For example, when a video signal is transmitted without being encoded, transmission can be performed using SDI or IP, and when a video signal is transmitted after being encoded, transmission can be performed using IP. In this embodiment, the imaging device 10 transmits a video signal to the first transmitting device 20 without encoding it, and the first transmitting device 20 encodes the video signal before transmitting it to the second transmitting device 30. However, encoding may be performed by the imaging device 10, or the first transmitting device 20 may not perform encoding.

[0033] The second transmitting device 30 aggregates video signals transmitted from a plurality of first transmitting devices 20 and transmits the video signals to the receiving device 40 via a transmission path (for example, an IP network). Note that the video signals do not necessarily need to be aggregated in the second transmitting device 30, and the first transmitting device 20 may directly transmit the video signals to the receiving device 40 via various transmission paths such as a broadcast transmission path, a terrestrial IMT (International Mobile Telecommunication) network, optical fiber, or a Wi-Fi (registered trademark) line.

[0034] The receiving device 40 may be any device that can receive video transmission from the first transmitting device 20 or the second transmitting device 30. The receiving device 40 may be, for example, a head-mounted display, VR (Virtual Reality) goggles, a tablet terminal, a smartphone, or a PC (Personal Computer).

[0035] (First transmitting device) Next, the first transmitting device 20 according to the first embodiment will be described.

[0036] As shown in Fig. 1, the first transmission device 20 includes a video receiving unit 21, a video encoding unit 22, a first ID assigning unit 23, a storage unit 24, and a video transmitting unit 25. The video encoding unit 22 and the first ID assigning unit 23 constitute a control unit (controller). The control unit may be constituted by dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), or may be constituted by a processor, or may be constituted by including both. The video receiving unit 21 and the video transmitting unit 25 constitute a communication interface.

[0037] The video receiving unit 21 receives video signals and metadata from the multiple image capture devices 10 and outputs them to the video encoding unit 22 .

[0038] The video encoding unit 22 encodes the video signal input from the video receiving unit 21 using any video encoding method such as H.265 / HEVC (High Efficiency Video Coding) to generate an encoded video signal. For efficient transmission, the video encoding unit 22 may perform compression using predictive coding that utilizes correlation between the video signals. The video encoding unit 22 then outputs the encoded video signal to the storage unit 24.

[0039] In the present invention, video signals are divided into multiple groups according to the shooting positions. Multiple video signals captured by multiple imaging devices 10 can be grouped in units of video signal groups used to generate video from viewpoints different from the shooting positions (used for viewpoint interpolation). This grouping is referred to as "first-layer grouping" to distinguish it from grouping described later. In other words, the first-layer group is a group to which multiple video signals used to generate video from viewpoints different from the shooting positions in the receiving device 40 belong.

[0040] The first ID assigning unit 23 receives an ID (first group ID) for identifying a group in the first layer through an operation by the operator of the first transmission device 20, and stores the first group ID in association with the video signal in the storage unit 24. That is, the first ID assigning unit 23 assigns the first group ID to the video signal.

[0041] The first group ID will be described with reference to FIG. 2. FIG. 2 shows an example of shooting at a baseball field, where a total of 15 imaging devices 10 are installed behind the catcher on the field, five in the horizontal direction and three in the vertical direction. For ease of explanation, the position information p of these 15 imaging devices 10 is set to 1 to 15. Furthermore, a total of 15 imaging devices 10 are installed on the first base side of the field, five in the horizontal direction and three in the vertical direction. For ease of explanation, the position information p of these 15 imaging devices 10 is set to 16 to 30. Furthermore, a total of 15 imaging devices 10 are installed on the third base side of the field, five in the horizontal direction and three in the vertical direction. For ease of explanation, the position information p of these 15 imaging devices 10 is set to 31 to 45. Note that in the example shown in FIG. 2, the imaging devices 10 only capture video of what is in front of them from their shooting positions, but they may also capture video of the entire 360-degree surroundings from their shooting positions.

[0042] The receiving device 40 receives video signals captured by the imaging devices 10 with position information p=1 to 15 and interpolates viewpoints to present the user with video from a certain range of viewpoints from behind the catcher. For example, if the receiving device 40 displays a video signal captured by the imaging device 10 with position information p=8 and the user then moves within a predetermined range (e.g., a radius of several meters), the receiving device 40 can present the user with video corresponding to the user's viewpoint. Similarly, the receiving device 40 can present the user with video from a certain range of viewpoints from the first base side by receiving video signals captured by the imaging devices 10 with position information p=16 to 30. Similarly, the receiving device 40 can present the user with video from a certain range of viewpoints from the third base side by receiving video signals captured by the imaging devices 10 with position information p=31 to 45.

[0043] For example, when video is captured by imaging devices 10 with position information p=1 to 45 as shown in FIG. 2, the first ID assigning unit 23 assigns a first group ID of "I" to 15 video signals captured from behind the catcher, assigns a first group ID of "II" to 15 video signals captured from the first base side, and assigns a first group ID of "III" to 15 video signals captured from the third base side. The first ID assigning unit 23 may assign the first group ID to all of the video signals. Furthermore, when the video encoding unit 22 performs compression using the correlation between the respective video signals, the first ID assigning unit 23 may assign the first group ID only to reference video signals (for example, video signals captured by imaging devices 10 with position information p=8, 23, 38).

[0044] Referring again to Figure 1, the memory unit 24 stores the encoded video signal and metadata (position information) input from the video encoding unit 22, as well as the metadata (information indicating the first group ID) input from the first ID assignment unit 23.

[0045] The video transmission unit 25 transmits the encoded video signal and metadata (information indicating the position information and the first group ID) stored in the storage unit 24 to the second transmission device 30.

[0046] The imaging device 10 and a part or all of the first transmitting device 20 may be integrated together. For example, if the imaging device 10 has the function of the video encoding unit 22, the video receiving unit 21 of the first transmitting device 20 receives the encoded video signal from the imaging device 10 and outputs it to the storage unit 24.

[0047] (Second transmitting device) Next, the second transmission device 30 according to the first embodiment will be described.

[0048] As shown in FIG. 1, the second transmission device 30 includes a video receiving unit 31, a second ID assigning unit 32, a storage unit 33, a viewing request receiving unit 34, a viewpoint information receiving unit 35, a position determining unit 36, and a video transmitting unit 37. The second ID assigning unit 32 and the position determining unit 36 ​​constitute a control unit. The control unit may be constituted by dedicated hardware such as an ASIC or FPGA, a processor, or may include both. The video receiving unit 31, the viewing request receiving unit 34, the viewpoint information receiving unit 35, and the video transmitting unit 37 constitute a communication interface.

[0049] The video receiving unit 31 receives the encoded video signals and metadata transmitted from the plurality of first transmission devices 20, and outputs the received encoded video signals and metadata to the storage unit 33.

[0050] Video signals captured by multiple imaging devices 10 can be grouped in units of groups of video signals captured in the same location. This grouping is referred to as "second-level grouping" to distinguish it from the first-level grouping described above. In other words, a second-level group is one or more first-level groups to which multiple video signals captured in the same location belong.

[0051] The second ID assigning unit 32 receives an ID (second group ID) for identifying a group in the second layer through an operation by the operator of the second transmission device 30, and stores the second group ID in association with the video signal in the storage unit 33. In other words, the second ID assigning unit 32 assigns the second group ID to the video signal.

[0052] The second group ID will be described with reference to Fig. 3. In the example shown in Fig. 3, the second transmission device 30 receives video signals captured at location A from the first transmission device 20A. Specifically, the second transmission device 30 receives 15 video signals with a first group ID of I captured by the imaging devices 10 with position information p of 1 to 15, 15 video signals with a first group ID of II captured by the imaging devices 10 with position information p of 16 to 30, and 15 video signals with a first group ID of III captured by the imaging devices 10 with position information p of 31 to 45. The second transmission device 30 also receives video signals captured at location B from the first transmission device 20B. Specifically, the second transmitting device 30 receives from the first transmitting device 20B 15 video signals of a first group ID=I captured by the imaging devices 10 with position information p=46 to 60, 15 video signals of a first group ID=II captured by the imaging devices 10 with position information p=61 to 75, and 15 video signals of a first group ID=III captured by the imaging devices 10 with position information p=76 to 90. The second transmitting device 30 also receives video signals captured at location C from the first transmitting device 20C. Specifically, the second transmitting device 30 receives from the first transmitting device 20C 15 video signals of the first group ID=I captured by the imaging devices 10 with position information p=91 to 105, 15 video signals of the first group ID=II captured by the imaging devices 10 with position information p=106 to 120, and 15 video signals of the first group ID=III captured by the imaging devices 10 with position information p=121 to 135.

[0053] In addition, the second ID assignment unit 32 assigns a second group ID, for example, "A" to the 45 video signals taken at location A, assigns a second group ID, for example, "B" to the 45 video signals taken at location B, and assigns a second group ID, for example, "C" to the 45 video signals taken at location C.

[0054] Figure 4 shows a hierarchical structure in which video signals are grouped into two hierarchical levels. As shown in Figure 3, 45 video signals are captured at each of locations A, B, and C. In this case, the 45 video signals captured at location A are classified into group A with a second group ID of A. Group A is further classified into 15 video signals belonging to a first group ID of I, 15 video signals belonging to a first group ID of II, and 15 video signals belonging to a first group ID of III. Similarly, the 45 video signals captured at location B are classified into group B with a second group ID of B. Group B is further classified into 15 video signals belonging to a first group ID of I, 15 video signals belonging to a first group ID of II, and 15 video signals belonging to a first group ID of III. In addition, the 45 video signals captured at location C are classified into group C with second group ID=C, and group C is further classified into 15 video signals belonging to first group ID=I, 15 video signals belonging to first group ID=II, and 15 video signals belonging to first group ID=III.

[0055] Referring back to FIG. 1, the storage unit 33 stores the encoded video signal and metadata input from the video receiving unit 31, and the metadata input from the second ID assigning unit 32.

[0056] When the viewing request receiving unit 34 receives a viewing request indicating the content to be viewed from the receiving device 40 , the viewing request receiving unit 34 outputs the viewing request to the video transmitting unit 37 .

[0057] When the viewpoint information receiving unit 35 receives viewpoint information indicating the viewpoint position of the user of the receiving device 40 (e.g., the position of the receiving device 40) from the receiving device 40, it outputs the viewpoint information to the position determining unit 36. For example, the viewpoint position information is three-dimensional coordinates in a global coordinate system. Alternatively, the viewpoint position information may be three-dimensional coordinates in a local coordinate system based on a default user position.

[0058] When viewpoint information is input from viewpoint information receiving unit 35, position determining unit 36 ​​determines whether or not the change in the user's viewpoint position is accompanied by a change in ID (first group ID and second group ID). Specifically, position determining unit 36 ​​identifies a request ID, which is the ID of a video signal corresponding to the change in the user's viewpoint position, and determines whether or not the request ID is the same as the ID of the video signal transmitted immediately before.

[0059] If the request ID is the same as the ID of the video signal transmitted immediately before, the position determination unit 36 ​​outputs the position information of the multiple image capture devices 10 that captured the multiple video signals necessary to generate a video corresponding to the user's viewpoint position from the group of video signals to which the request ID is assigned to the video transmit unit 37. For example, the position determination unit 36 ​​determines the shooting position corresponding to the user's viewpoint position, and outputs the position information of the image capture devices 10 that are located in positions adjacent to the shooting position or in positions surrounding the shooting position to the video transmit unit 37.

[0060] In addition, if the request ID is different from the ID of the video signal transmitted immediately before, the position determination unit 36 ​​outputs to the video transmission unit 37 the position information of the imaging device 10 that captured the default video signal from the group of video signals to which the request ID is assigned.

[0061] The video transmitting unit 37 transmits the video signal to the receiving device 40. In this specification, "transmitting a video signal" means simultaneously transmitting the metadata attached (multiplexed) to the video signal. The video transmitting unit 37 can also transmit only the metadata. The video signal belonging to the first layer group transmitted by the video transmitting unit 37 may be compressed by predictive coding using correlation between video signals by the video encoding unit 22 of the first transmitting device 20.

[0062] When a viewing request is input from the viewing request receiving unit 34, the video transmitting unit 37 acquires from the storage unit 33 a default video signal of the content requested to be viewed, all ID information (information indicating the first group ID and the second group ID) related to the content requested to be viewed, and location information of the image capturing device 10 representing each first layer group, and transmits these to the receiving device 40. The receiving device 40 presents to the user what viewpoint positions can be selected based on the ID information and the location information of the image capturing device 10.

[0063] Furthermore, when the position information is input from the position determination unit 36, the video transmission unit 37 acquires from the storage unit 33 the video signal captured by the imaging device 10 having the position information (the video signal corresponding to the position information), and transmits it to the receiving device 40. In other words, if the request ID is the same as the ID of the video signal transmitted immediately before, the video transmission unit 37 transmits, from the group of video signals to which the request ID is assigned, a plurality of video signals necessary to generate a video corresponding to the user's viewpoint position, and if the request ID is different from the ID of the video signal transmitted immediately before, the video transmission unit 37 transmits a default video signal from the group of video signals to which the request ID is assigned.

[0064] 5 is a diagram showing an example of the structure of a file in the case where an ID and a video signal are stored in a file in ISO Base Media File Format such as OMAF. This format is made up of basic units called boxes.

[0065] In the file configuration shown in Fig. 5A, when n video signals having a common second group ID and a common first group ID are stored in a file, the groups to which the video signals belong are indicated by storing the n video signals under boxes indicating the second group ID and the first group ID. In the file configuration shown in Fig. 5B, when n video signals having a common second group ID and a common first group ID are stored in a file, the groups to which the video signals belong are indicated by storing boxes indicating the second group ID and the first group ID along with the tracks storing each video signal.

[0066] In this embodiment, two-level grouping has been described, but three or more levels of grouping may be performed depending on the content for user operation. Even when three or more levels of grouping are performed, each video signal can be identified by similar hierarchical structure. For example, one or more second-level groups to which video signals captured in the same area belong may be grouped as a third-level group.

[0067] (receiving device) Next, the receiving device 40 according to the first embodiment will be described.

[0068] As shown in FIG. 1, receiving device 40 includes viewing request transmitting unit 41, video receiving unit 42, video decoding unit 43, storage unit 44, viewpoint position detecting unit 45, viewpoint information transmitting unit 46, viewpoint interpolation unit 47, operation information adding unit 48, and display unit 49. Video decoding unit 43, viewpoint position detecting unit 45, viewpoint interpolation unit 47, and operation information adding unit 48 constitute a control unit. The control unit may be constituted by dedicated hardware such as an ASIC or FPGA, a processor, or may include both. Viewing request transmitting unit 41, video receiving unit 42, and viewpoint information transmitting unit 46 constitute a communication interface.

[0069] The viewing request sending unit 41 sends a viewing request indicating the content selected by the user of the receiving device 40 to the second transmitting device 30.

[0070] The video receiving unit 42 receives the video signal and metadata (location information and ID information) from the second transmitting device 30. The video receiving unit 42 outputs the received video signal and metadata to the video decoding unit 43 in association with each other.

[0071] The video decoding unit 43 decodes the video signal to generate decoded video, and outputs the decoded video to the storage unit 44 .

[0072] The storage unit 44 stores the decoded video generated by the video decoding unit 43.

[0073] The viewpoint position detection unit 45 detects the viewpoint position of the user and outputs viewpoint information indicating the detected viewpoint position to the viewpoint information transmission unit 46. For example, the viewpoint position detection unit 45 detects the viewpoint position by acquiring an image of the user's eyes captured by an imaging device included in the receiving device 40 and analyzing the image using any known technology. Alternatively, the viewpoint position detection unit 45 may be an eye-gaze sensor included in the receiving device 40 separately from the control unit. The control unit acquires the user's viewpoint position using the viewpoint position detection unit 45.

[0074] The viewpoint information transmitting unit 46 transmits the viewpoint information detected by the viewpoint position detecting unit 45 to the second transmitting device 30. The viewpoint information transmitting unit 46 may transmit the viewpoint information to the second transmitting device 30 at predetermined intervals, or may transmit the viewpoint information to the second transmitting device 30 only when the amount of change in the viewpoint position exceeds a threshold.

[0075] The viewpoint interpolation unit 47 performs viewpoint interpolation using a plurality of decoded videos having a common first group ID and a common second group ID stored in the storage unit 44 (i.e., decoded videos obtained by decoding video signals corresponding to the position information determined by the position determination unit 36), and generates a video corresponding to the viewpoint position detected by the viewpoint position detection unit 45. Any known technology (see, for example, Patent Document 1) can be used for viewpoint interpolation. The viewpoint interpolation unit 47 outputs the viewpoint-interpolated decoded video to the operation information addition unit 48.

[0076] In response to a user's viewing request, the operation information adding unit 48 obtains default decoded video from the storage unit 44, adds operation information to the decoded video, and outputs the decoded video to the display unit 49. After the viewpoint interpolation unit 47 performs viewpoint interpolation, the operation information adding unit 48 obtains the viewpoint-interpolated decoded video from the viewpoint interpolation unit 47, adds operation information to the decoded video, and outputs the decoded video to the display unit 49.

[0077] Here, the operation information is information indicating to the user an operation method for changing the viewpoint position. For example, the operation information is information indicating an operation method for changing the viewpoint position to a different viewpoint position at the same location or to a different viewpoint position at a different location. The operation information may include an icon. The user can request a change in the viewpoint position by performing an operation based on the operation information. For example, if the receiving device 40 is a head-mounted display, the user may perform an operation based on the operation information by the direction of their line of sight. At this time, the line of sight direction is detected by the viewpoint position detection unit 45. Furthermore, if the receiving device 40 is a tablet terminal, the operation based on the operation information may be performed by a screen operation such as a flick or swipe. Furthermore, if the receiving device 40 is a non-mobile or non-portable device having a flat panel display, the operation based on the operation information may be performed using a remote control.

[0078] The display unit 49 is, for example, a liquid crystal display or an organic EL (Electro-Luminescence) display, and displays the decoded video and operation information input from the operation information adding unit 48.

[0079] FIG. 6 shows an example of display of images and operation information on display unit 49. In the example shown in FIG. 6, image 481 and operation information 482 to 486 are displayed. Operation information 482 indicates that currently displayed image 481 is an image based on the image group of location C with first group ID=II. Operation information 483 indicates that the viewpoint position at location C can be changed by a predetermined operation (the currently displayed image 481 can be changed to an image based on the image group of location C with first group ID=I). Operation information 484 indicates that the viewpoint position at location C can be changed by a predetermined operation (the currently displayed image 481 can be changed to an image based on the image group of location C with first group ID=III). Operation information 485 indicates that the viewpoint position can be changed to a different location by a predetermined operation (the currently displayed image 481 can be changed to an image captured at location A). Operation information 486 indicates that the viewpoint position can be changed to a different location by a predetermined operation (the currently displayed image 481 can be changed to an image captured at location B).

[0080] When the user performs an operation based on the operation information displayed on the display unit 49, the viewpoint position detection unit 45 detects the viewpoint position corresponding to the operation. This allows the user to request the second transmission device 30 to change the viewpoint position.

[0081] (Operation sequence) Next, an operation sequence of the video transmission system 1 according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram showing an operation sequence between the second transmitting device 30 and the receiving device 40.

[0082] In step S101, the receiving device 40 transmits a viewing request indicating the content selected by the user to the second transmitting device 30 via the viewing request transmitting unit 41. The second transmitting device 30 receives the viewing request transmitted from the receiving device 40 via the viewing request receiving unit 34.

[0083] In step S102, the second transmission device 30 transmits, via the video transmission unit 37, to the receiving device 40, all ID information and location information of the imaging devices 10 representing each of the first layer groups for the content requested for viewing by the receiving device 40. The receiving device 40 receives the above information regarding the content requested for viewing from the second transmission device 30 via the video reception unit 42. For example, if the installation locations of the imaging devices 10 are as shown in FIG. 2, the location information of the imaging devices 10 representing each of the first layer groups is set to be location information p=8, 23, 38 of the imaging devices 10 located in the center. Note that the video transmission unit 37 may transmit multiple pieces of location information for each of the first layer groups to the receiving device 40.

[0084] In step S103, the second transmitting device 30 transmits, via the video transmitting unit 37, a default video signal for the content requested for viewing by the receiving device 40 to the receiving device 40. It is assumed that the second transmitting device 30 predetermines a default video signal for each piece of content. For example, if the video signals for the content requested for viewing are grouped as shown in FIG. 4, the default video is set to video signal 8 of second group ID=A and first group ID=I (video signal captured by imaging device 10 with position information p=8 located in the center behind the catcher in FIG. 2).

[0085] In step S104, the receiving device 40 receives, via the video receiving unit 42, a default video signal of the content requested for viewing from the second transmitting device 30. Then, the receiving device 40 decodes the video signal via the video decoding unit 43, and displays the default video on the display unit 49.

[0086] In step S105, the receiving device 40 causes the viewpoint information transmitting section 46 to transmit the viewpoint information to the second transmitting device 30.

[0087] In step S106, the second transmission device 30 identifies a request ID, which is the ID of a video signal corresponding to a change in the user's viewpoint position, using the position determination unit 36. If the request ID is the same as the ID of the video signal transmitted immediately before, the second transmission device 30 proceeds to step S107, and if the request ID is different from the ID of the video signal transmitted immediately before, the second transmission device 30 proceeds to step S109.

[0088] In step S107, the second transmission device 30 transmits, via the video transmission unit 37, to the reception device 40, a video signal required to generate a video corresponding to the user's viewpoint position.

[0089] In step S108, the receiving device 40 causes the viewpoint interpolation unit 47 to perform viewpoint interpolation processing using the multiple video signals required for viewpoint interpolation received from the second transmitting device 30. Then, the receiving device 40 displays the viewpoint-interpolated video on the display unit 49. Then, the receiving device 40 returns the processing to step S105.

[0090] In step S109, the second transmission device 30 causes the video transmission unit 37 to transmit to the reception device 40 a default video signal from the group of video signals to which the request ID has been assigned.

[0091] In step S110, the receiving device 40 receives the default video signal with the changed viewpoint position from the second transmitting device 30 via the video receiving unit 42. Then, the receiving device 40 decodes the video signal via the video decoding unit 43 and displays the default video on the display unit 49. Then, the receiving device 40 returns the process to step S105.

[0092] As described above, the video transmission system 1, which transmits multiple video signals captured at different positions, groups the video signals and assigns IDs to them. Grouping multiple video signals into first-layer groups makes it possible to easily identify multiple video signals to be used for viewpoint interpolation. Furthermore, grouping multiple video signals into second-layer groups makes it possible to present to the user what kinds of viewpoint position changes are possible. Then, by operating in accordance with the operation information displayed on the display unit 49, the user can view video with different viewpoint positions within the same location and with different viewpoint positions.

[0093] Second Embodiment Next, a video transmission system according to the second embodiment will be described. FIG. 8 is a diagram showing a video transmission system 2 according to the second embodiment. The video transmission system 2 includes a plurality of image capture devices 10, a plurality of first transmission devices 20, a second transmission device 30a, and a reception device 40a. The image capture devices 10 and the first transmission device 20 of this embodiment are the same as the image capture device 10 and the first transmission device 20 of the first embodiment, and therefore a description thereof will be omitted. The second transmission device 30a and the reception device 40a of this embodiment share some common components with the second transmission device 30 and the reception device 40 of the first embodiment, and therefore the same reference numerals will be used to designate common components, and a description thereof will be omitted where appropriate.

[0094] The receiving device 40a of this embodiment differs from the receiving device 40 of the first embodiment in that it further includes an ID information detection unit 50 and a viewpoint information transmission unit 46a instead of the viewpoint information transmission unit 46. The ID information detection unit 50 also constitutes a control unit.

[0095] When a user requests a change in the viewpoint position by performing an operation based on the operation information displayed on the display unit 49, the ID information detection unit 50 detects an ID (request ID) assigned to a group of video signals corresponding to a new viewpoint position requested by the user. The ID information detection unit 50 then outputs the detected request ID to the viewpoint information transmission unit 46a as viewpoint information. For example, in FIG. 6, when a user performs a swipe operation along the arrow icon indicated by the operation information 483, the ID information detection unit 50 detects a first group ID of I and a second group ID of C as request IDs. Also, in FIG. 6, when a user performs a swipe operation along the arrow icon indicated by the operation information 485, the ID information detection unit 50 detects a first group ID of default value and a second group ID of A as request IDs. Note that when the first group ID is the default value, only the second group ID may be included as the request ID.

[0096] If the user does not perform an operation based on the operation information displayed on the display unit 49, the viewpoint information transmission unit 46a transmits the viewpoint information detected by the viewpoint position detection unit 45 to the second transmission device 30a, and if the user performs an operation based on the operation information displayed on the display unit 49, the viewpoint information transmission unit 46a transmits the viewpoint information (request ID) detected by the ID information detection unit 50 to the second transmission device 30a.

[0097] The second transmitting device 30a of this embodiment differs from the second transmitting device 30 of the first embodiment in that it is equipped with a viewpoint information receiving unit 35a, a position determination unit 36a, and a video transmitting unit 37a instead of the viewpoint information receiving unit 35, the position determination unit 36, and the video transmitting unit 37.

[0098] When the viewpoint information receiving unit 35a receives viewpoint information that does not include a request ID, it outputs the viewpoint information to the position determining unit 36a, as in the first embodiment. Furthermore, when the viewpoint information receiving unit 35a receives viewpoint information that includes a request ID, it identifies position information that corresponds to a default video signal from among the group of video signals to which the request ID has been assigned, and transmits the identified position information to the video transmitting unit 37a.

[0099] When viewpoint information not including a request ID is input from the viewpoint information receiving unit 35a, the position determining unit 36a outputs, to the video transmitting unit 37a, position information of the multiple imaging devices 10 that captured video signals required to generate a video corresponding to the user's viewpoint position. Furthermore, when viewpoint information including a request ID is input from the viewpoint information receiving unit 35a, the position determining unit 36a outputs, to the video transmitting unit 37a, position information corresponding to a default video signal from the group of video signals to which the request ID has been assigned.

[0100] When the video transmission unit 37a receives position information from the viewpoint information receiving unit 35a or the position determination unit 36a, it acquires from the memory unit 33 the video signal captured by the imaging device 10 having the position information (the video signal corresponding to the position information) and transmits it to the receiving device 40a.

[0101] (Operation sequence) Next, an operation sequence of the video transmission system 2 according to this embodiment will be described with reference to Fig. 9. Fig. 9 is a diagram showing an operation sequence between the second transmitting device 30a and the receiving device 40a. Steps S201 to S204 are the same as steps S101 to S104 of the first embodiment described with reference to Fig. 7, and therefore description thereof will be omitted.

[0102] In step S205, the receiving device 40a transmits the viewpoint information to the second transmitting device 30a via the viewpoint information transmitting section 46a.

[0103] In step S206, the second transmission device 30a determines whether or not a request ID is included in the viewpoint information using the position determination unit 36a. If the viewpoint information does not include a request ID, the second transmission device 30a proceeds to step S207, and if the viewpoint information includes a request ID, the second transmission device 30a proceeds to step S209.

[0104] Steps S207 to S210 are the same as steps S107 to S110 in the first embodiment described with reference to FIG. 7, and therefore a description thereof will be omitted.

[0105] As described above, in this embodiment, the detection of the request ID is performed by the receiving device 40a instead of the transmitting device 30a, but in this case too, the same effects as in the first embodiment can be obtained.

[0106] Third Embodiment Next, a video transmission system according to the third embodiment will be described. FIG. 10 is a diagram showing a video transmission system 3 according to the third embodiment. The video transmission system 3 includes a plurality of image capture devices 10, a plurality of first transmission devices 20, a second transmission device 30b, and a reception device 40b. The image capture devices 10 and the first transmission device 20 of this embodiment are the same as the image capture device 10 and the first transmission device 20 of the first embodiment, and therefore a description thereof will be omitted. The second transmission device 30b and the reception device 40b of this embodiment share some common components with the second transmission device 30 and the reception device 40 of the first embodiment, and therefore the same reference numerals will be used to designate common components, and a description thereof will be omitted where appropriate.

[0107] In the first and second embodiments described above, a bidirectional transmission path is assumed as the transmission path between the second transmitting device 30, 30a and the receiving device 40, 40a. On the other hand, in this embodiment, a unidirectional transmission path is assumed as the transmission path between the second transmitting device 30b and the receiving device 40b. The transmission path may be a transmission path compatible with IP multicast or a transmission path compatible with broadcast waves. Note that IP multicast over a communication line may be transmitted by broadcast waves. Broadcasting systems compatible with IP packet transmission, such as ISDB (Integrated Services Digital Broadcasting)-S3 and ATSC (Advanced Television Systems Committee) 3.0, are considered to be transmission paths similar to IP multicast over a communication line.

[0108] The second transmitting device 30b of this embodiment differs from the second transmitting device 30 of the first embodiment in that it does not have a viewpoint information receiving unit 35 and a position determination unit 36, and that it has a video transmitting unit 37b instead of the video transmitting unit 37.

[0109] When IP multicast transmission is performed over a communication line, upon receiving a viewing request from viewing request receiving unit 34, video transmitting unit 37b acquires all video signals relating to the content requested to be viewed from storage unit 33. Then, video transmitting unit 37b simultaneously transmits all video signals to receiving device 40b. As in the other embodiments, metadata (ID information and location information) is multiplexed onto the video signals. For example, if the video signals of the content requested to be viewed are grouped as shown in FIG. 4, video transmitting unit 37b simultaneously transmits 145 video signals to receiving device 40b.

[0110] On the other hand, when broadcast transmission is performed, no viewing request is made by the user, and regardless of a viewing request from receiving device 40b, video transmitting unit 37b always acquires all video signals related to all content from storage unit 33. Then, video transmitting unit 37b simultaneously transmits all video signals related to all content to receiving device 40b. Then, content selection is performed within receiving device 40b. In other words, in the case of a broadcast transmission path, it is not necessary to provide viewing request transmitting unit 41 and viewing request receiving unit 34.

[0111] Receiving device 40b of this embodiment differs from receiving device 40 of the first embodiment in that it does not include viewpoint information transmitting unit 46, that it further includes ID information detecting unit 50, position determining unit 52, and viewpoint changing unit 53, and that it includes viewpoint interpolating unit 47b and operation information adding unit 48b instead of viewpoint interpolating unit 47 and operation information adding unit 48. ID information detecting unit 50, position determining unit 52, and viewpoint changing unit 53 also constitute a control unit.

[0112] When viewpoint information is input from viewpoint position detection unit 45, position determination unit 52 determines whether the viewpoint position has changed. For example, position determination unit 52 determines that the viewpoint position has changed when the amount of change in the viewpoint position exceeds a threshold. If position determination unit 52 determines that the viewpoint position has changed, it identifies position information of the multiple imaging devices 10 that captured the multiple video signals required to generate an image corresponding to the user's viewpoint position, and outputs the identified position information to viewpoint interpolation unit 47b.

[0113] When the position information is input from the position determination unit 52, the viewpoint interpolation unit 47b acquires a decoded video corresponding to the position information from the storage unit 44. Then, the viewpoint interpolation unit 47b performs viewpoint interpolation using the acquired decoded video, and outputs the viewpoint-interpolated decoded video to the operation information addition unit 48b.

[0114] When a user requests a change in the viewpoint position by performing an operation based on the operation information displayed on the display unit 49, the ID information detection unit 50 detects an ID (request ID) assigned to a group of images corresponding to the new viewpoint position requested by the user. Then, the ID information detection unit 50 outputs the detected request ID to the viewpoint change unit 53.

[0115] When a request ID is input from the ID information detection unit 50, the viewpoint change unit 53 obtains from the memory unit 44 a default decoded image from among the decoded images of the video signal group to which the request ID has been assigned, and outputs the default decoded image to the operation information addition unit 48b.

[0116] During content playback, operation information adding unit 48b first acquires default decoded video from storage unit 44, adds operation information to the decoded video, and outputs the decoded video to display unit 49. After viewpoint interpolation is performed by viewpoint interpolation unit 47b, operation information adding unit 48b acquires viewpoint-interpolated decoded video from viewpoint interpolation unit 47b, adds operation information to the decoded video, and outputs the decoded video to display unit 49. After viewpoint changing unit 53 detects a request ID, operation information adding unit 48b acquires default decoded video with a changed viewpoint position from viewpoint changing unit 53, adds operation information to the decoded video, and outputs the decoded video to display unit 49.

[0117] (Operation sequence) Next, an operation sequence of the video transmission system 3 according to this embodiment will be described with reference to Fig. 11. Fig. 11 is a diagram showing an operation sequence between the second transmitting device 30b and the receiving device 40b when a video signal is transmitted by IP multicast.

[0118] In step S301, the receiving device 40b transmits a viewing request indicating the content selected by the user to the second transmitting device 30b via the viewing request transmitting unit 41. The second transmitting device 30b receives the viewing request transmitted from the receiving device 40b via the viewing request receiving unit 34.

[0119] In step S302, the second transmission device 30b transmits all video signals related to the content requested for viewing from the receiving device 40b together with metadata (ID information and location information) to the receiving device 40b via the video transmission unit 37b. The receiving device 40b receives all video signals related to the content requested for viewing together with the metadata from the second transmission device 30b via the video reception unit 42.

[0120] In step S303, the receiving device 40b decodes the video signal using the video decoding unit 43. Then, the receiving device 40b displays, on the display unit 49, the default video of the content requested for viewing.

[0121] In step S304, receiving device 40b determines whether or not there is a change (small change) in the viewpoint position that does not involve a change in ID, using position determination unit 52. If there is a small change in the viewpoint position, receiving device 40b proceeds to step S305, and if there is no small change in the viewpoint position, proceeds to step S306.

[0122] In step S305, the receiving device 40b causes the viewpoint interpolation unit 47b to perform viewpoint interpolation processing using the multiple decoded videos to generate a video corresponding to the user's viewpoint position. Then, the receiving device 40b displays the viewpoint-interpolated video on the display unit 49. Then, the receiving device 40b returns the processing to step S304.

[0123] In step S306, the receiving device 40b determines whether or not there has been a change (major change) in the viewpoint position accompanied by a change in ID, using the ID information detection unit 50. If there has been a major change in the viewpoint position, the receiving device 40b detects the request ID and proceeds to step S307, but if there has not been a major change in the viewpoint position, the processing returns to step S304.

[0124] In step S307, the receiving device 40b acquires a default decoded video from among the decoded videos of the video signal group to which the request ID has been assigned, by the viewpoint changing unit 53. Then, the receiving device 40b displays the default video on the display unit 49.

[0125] In the case of broadcast transmission, the operation of step S301 is not performed, and in step S302, the second transmission device 30b transmits all video signals related to all content together with metadata (ID information and location information) to the reception device 40b via the video transmission unit 37b. Then, in step S303, the reception device 40b displays default video of the content selected by the user. The operations from step S304 onwards are the same as in the case of IP multicast transmission.

[0126] As described above, the second transmission device 30b transmits all video signals to the reception device 40b together with metadata (ID information indicating the grouping of the first and second layers, and location information). Therefore, when the viewpoint position is changed in the reception device 40b, the decoded video required in response to the change in viewpoint position can be identified. In this way, the present invention can also be applied to cases where video signals are broadcast or distributed via IP multicast.

[0127] <Program> A computer capable of executing program instructions may be used to function as the first transmitting device 20, the second transmitting devices 30, 30a, and 30b, and the receiving devices 40, 40a, and 40b. FIG. 12 is a block diagram showing a schematic configuration of a computer functioning as the first transmitting device 20, the second transmitting devices 30, 30a, and 30b, or the receiving devices 40, 40a, and 40b. Here, the computer 100 may be a general-purpose computer, a dedicated computer, a workstation, a PC, an electronic notepad, or the like. The program instructions may be program code, code segments, or the like for performing the necessary tasks.

[0128] 12, computer 100 includes processor 110, ROM (Read Only Memory) 120, RAM (Random Access Memory) 130, storage 140, input unit 150, output unit 160, and communication interface (I / F) 170. Each component is communicably connected to one another via bus 180. Processor 110 is specifically a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), SoC (System on a Chip), or the like, and may be configured by multiple processors of the same or different types.

[0129] The processor 110 controls each component and performs various arithmetic processing. That is, the processor 110 reads a program from the ROM 120 or the storage 140 and executes the program using the RAM 130 as a work area. The processor 110 controls each component and performs various arithmetic processing in accordance with the program stored in the ROM 120 or the storage 140. In this embodiment, the program according to the present disclosure is stored in the ROM 120 or the storage 140.

[0130] The program may be recorded on a recording medium readable by computer 100. Using such a recording medium, the program can be installed on computer 100. Here, the recording medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a CD-ROM, a DVD-ROM, or a USB (Universal Serial Bus) memory. Furthermore, the program may be downloaded from an external device via a network.

[0131] The ROM 120 stores various programs and various data. The RAM 130 temporarily stores programs or data as a working area. The storage 140 is configured with an HDD (Hard Disk Drive) or SSD (Solid State Drive) and stores various programs including the operating system and various data.

[0132] The input unit 150 includes one or more input interfaces that receive input operations from a user and acquire information based on the user operations. For example, the input unit 150 is, but is not limited to, a pointing device, a keyboard, a mouse, etc.

[0133] The output unit 160 includes one or more output interfaces that output information. For example, the output unit 160 is a display that outputs information as an image, or a speaker that outputs information as sound, but is not limited to these. Note that if the output unit 160 is a touch panel display, it also functions as the input unit 150.

[0134] The communication interface 170 is an interface for communicating with an external device.

[0135] Although the above-described embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, with regard to the constituent blocks or processing steps described in the embodiments, multiple blocks or processing steps can be combined into one, or one block or processing step can be divided into multiple blocks. [Explanation of symbols]

[0136] 1,2,3 Video Transmission System 10. Imaging device 20 First transmitter 21 Video receiving unit 22 Video Encoding Unit 23 First ID Assignment Department 24 Memory section 25 Video transmission unit 30, 30a, 30b Second transmitter 31 Video receiving unit 32 2nd ID assignment section 33 Storage section 34 Viewing request receiving unit 35, 35a Viewpoint information receiving unit 36 Position determination section 37 Video transmission unit 40, 40a, 40b Receiving device 41 Viewing request sending unit 42 Video receiving unit 43 Video Decoding Unit 44 Memory section 45 Viewpoint position detection unit 46, 46a Viewpoint information transmission unit 47,47b Viewpoint Interpolation 48,48b Operation information addition section 49 Display section 50 ID information detection unit 52 Position determination section 53 Viewpoint change section 100 computers 110 processors 120 ROM 130 RAM 140 Storage 150 Input section 160 Output section 170 Communication Interface 180 Bus 481 videos 482~486 Operation information

Claims

1. A transmitting device that transmits a plurality of video signals captured from different positions to a receiving device, The video signals are divided into a plurality of groups according to the shooting positions, a control unit that assigns an ID for identifying the group; a communication interface for transmitting the video signal to which the ID is assigned to the receiving device; Equipped with the control unit identifies a request ID that is an ID of a video signal corresponding to a change in a viewpoint position of a user of the receiving device; The communication interface transmits to the receiving device, if the request ID is the same as the ID of the video signal transmitted immediately before, a plurality of video signals from the group of video signals to which the request ID is assigned that are necessary to generate an image corresponding to the user's viewpoint position, and, if the request ID is different from the ID of the video signal transmitted immediately before, transmits to the receiving device a default video signal from the group of video signals to which the request ID is assigned.

2. The video signals are divided into a plurality of groups according to the shooting positions, The transmitting device according to claim 1 , wherein the control unit assigns a group ID to identify the group.

3. The transmitting device according to claim 2 , wherein a first hierarchical group among the plurality of groups is a group to which a plurality of video signals belong that are used to generate video from a viewpoint different from the shooting position in the receiving device.

4. The transmitting device according to claim 3 , wherein a second layer group among the plurality of groups is one or more of the first layer groups to which a plurality of video signals captured in the same location belong.

5. 5. The transmitting device according to claim 3, wherein the video signals belonging to the first layer group transmitted by the communication interface are compressed by predictive coding using correlation between video signals.

6. The transmitting device according to claim 1 , wherein the ID and the video signal are stored in a file in ISO Base Media File Format.

7. A receiving device for receiving a video signal transmitted by the transmitting device according to any one of claims 1 to 6, a control unit that decodes the video signal to generate a decoded video and acquires a user's viewpoint; a communication interface that transmits viewpoint information indicating a viewpoint position of the user to the transmitting device; when it is determined by the transmitting device that the request ID is identical to the ID of the video signal transmitted immediately before, the communication interface receives from the transmitting device a plurality of video signals, among the video signals to which the request ID is assigned, that are required to generate a video corresponding to the viewpoint position; When the transmitting device determines that the request ID is different from the ID of the video signal transmitted immediately before, the transmitting device receives a default video signal from the video signal group to which the request ID is assigned, and When the control unit receives the plurality of video signals, the control unit generates a video corresponding to the viewpoint position, a receiving device that, when receiving the default video signal, decodes the default video signal;

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