Video distribution system, edge server, and video distribution method

Abstract

To reduce the delay of VR video distribution while maintaining the user's quality of experience for a distributed VR video.SOLUTION: A video distribution system according to the present disclosure includes a server that processes video from a video source into a virtual reality (VR) video and compresses and encodes it, an edge server that transcodes the compression-encoded VR video from the server according to a user's viewing situation and distributes the transcoded VR video, and a user device that transmits the viewing status of the user to the edge server and receives the transcoded VR video from the edge server.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a technology that achieves low latency in video distribution while maintaining the user's quality of experience of VR video. [Background technology]

[0002] In recent years, there has been an increasing need for collaborative and remote work while being in different locations via a network. In order to provide users with a more realistic experience and a high level of immersion when performing collaborative and remote work, support for VR is required in addition to conventional 2D images. In a VR-compatible system, multiple users simultaneously share the same VR space via a network. Each user views a portion of the VR space through a wired or wireless VR headset.

[0003] As a method for delivering VR video, a technology has been proposed in which VR video is encoded according to the allowable bandwidth between a server and a user device (see, for example, Non-Patent Document 1). VR video is divided into multiple quality levels, compression-encoded according to the quality level, and the compressed and encoded VR video that matches the allowable bandwidth between the server and the user device is delivered.

[0004] As a method for distributing VR video, a technology has been proposed in which, when distributing the same content, panoramic video is divided into tiles and distributed (see, for example, Non-Patent Document 2). This technology predicts the areas that a new user is likely to view based on the past viewing data of multiple users, and based on the prediction, compresses and encodes tiles that are likely to be viewed at high quality, and compresses and encodes tiles that are unlikely to be viewed at low quality and distributes them.

[0005] One technique proposed for dividing VR video into tiles and distributing it involves using user gaze information to compress and encode the user's viewing area at high quality and the rest at low quality before distributing the tiled video (see, for example, non-patent document 3). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] G. He, J. Hu, H. Jiang and Y. Li, “Scalable Video Coding Based on User′s View for Real-Time Virtual Reality Applications,” in IEEE Communications Letters, vol. 22, no. 1, pp. 25-28, Jan. 2018. [Non-patent document 2] Shindo et al., "Initial study on 360-degree video transmission using head-mounted display information," Proceedings of the 80th National Conference, 2018, pp. 83-84. [Non-patent document 3] Lungaro, Pietro, et al. “Gaze-aware streaming solutions for the next generation of mobile VR experiences,” IEEE transactions on visualization and computer graphics, vol. 24, no. 4, pp-1535-1544, 2018. Summary of the Invention [Problem to be solved by the invention]

[0007] However, the resolution of VR video is increasing year by year, which leads to an increase in network traffic even if the technologies in Non-Patent Documents 1 to 3 are applied, resulting in an increase in delay in VR video distribution and a deterioration in the quality of user experience of the distributed VR video.

[0008] Therefore, in order to solve the above problem, the present disclosure aims to reduce the delay in VR video distribution while maintaining the user's quality of experience for the distributed VR video. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the video distribution system of the present disclosure applies a layered architecture of servers and edge servers to distribute video from video sources.

[0010] Specifically, the present disclosure provides: A server that processes and compresses video from a video source into VR (Virtual Reality) video. An edge server that transcodes the compressed and encoded VR video from the server according to the user's viewing situation and delivers the transcoded VR video; a user device that transmits the viewing status of the user to the edge server and receives the transcoded VR video from the edge server; A video distribution system comprising: is.

[0011] The present disclosure also provides: The server further divides the compressed and encoded VR video into tiles, The edge server transcodes the VR video divided into tiles from the server according to a viewing situation of the user, and delivers the transcoded VR video to the user device; The user device transmits, to the edge server, a high-priority tile number extracted based on the user's line of sight information for the VR video as the viewing situation. It is characterized by:

[0012] The present disclosure also provides: The edge server divides the compressed and encoded VR video from the server into tiles, transcodes the VR video according to the user's viewing situation, and delivers the transcoded VR video to the user device; The user device transmits, to the edge server, a high-priority tile number extracted based on the user's line of sight information for the VR video as the viewing situation. It is characterized by:

[0013] The present disclosure also provides: The edge server transcodes tiles with many high priorities into high-quality encoding and tiles with few high priorities into low-quality encoding according to the user's viewing situation, and distributes the transcoded VR video by unicast. It is characterized by:

[0014] The present disclosure also provides: The edge server transcodes tiles with many high priorities into high-quality encoding and tiles with few high priorities into low-quality encoding according to the user's viewing situation, and distributes the transcoded VR video by multicast. It is characterized by:

[0015] The present disclosure also provides: The edge server transcodes tiles with many high priorities to high quality encoding and tiles with few high priorities to low quality encoding according to the user's viewing situation, and broadcasts the transcoded VR video. It is characterized by:

[0016] The present disclosure also provides: The edge server classifies and transcodes tiles into three or more levels so that tiles with higher priority are coded with higher quality and tiles with fewer priority are coded with lower quality according to the user's viewing situation, and divides the tiles into two at any level. The tiles coded with higher quality are distributed by multicast and the other tiles are distributed by unicast. It is characterized by:

[0017] The present disclosure also provides: The edge server classifies and transcodes tiles into three or more levels so that more tiles with higher priority are coded with higher quality and fewer tiles with higher priority are coded with lower quality according to the user's viewing situation, divides the tiles into thirds at any level, and distributes the higher quality coded tiles of the transcoded VR video by multicast, distributes the lower quality coded tiles of the transcoded VR video by broadcast, and distributes the remaining medium quality coded tiles of the transcoded VR video by unicast. It is characterized by:

[0018] The present disclosure also provides: The edge server performs higher quality encoding on tiles corresponding to high-priority tile numbers received from the user device, and unicasts the tiles to the user device that transmitted the high-priority tile numbers. It is characterized by:

[0019] The present disclosure also provides: An edge server that transcodes compressed and encoded VR video according to the user's viewing situation and delivers the transcoded VR video. is.

[0020] The present disclosure also provides: A video distribution method that transcodes compressed and encoded VR video according to the user's viewing situation and distributes the transcoded VR video. is.

[0021] The above-disclosed inventions can be combined as much as possible. [Effects of the Invention]

[0022] In this way, the present disclosure can achieve low latency in video distribution while maintaining the user's quality of experience for the distributed VR video. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram illustrating a configuration of a video distribution system according to the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating a tile structure of the video distribution system of the present disclosure. [Figure 3] FIG. 2 is a diagram illustrating a tile structure of the video distribution system of the present disclosure. [Figure 4] 1 is a diagram illustrating a configuration of a video distribution system according to the present disclosure. [Figure 5] 1 is a diagram illustrating a configuration of a video distribution system according to the present disclosure. [Figure 6] 1 is a diagram illustrating a configuration of a video distribution system according to the present disclosure. [Figure 7] 1 is a diagram illustrating a configuration of a video distribution system according to the present disclosure. [Figure 8] 1 is a diagram illustrating a configuration of a video distribution system according to the present disclosure. [Figure 9] 1 is a diagram illustrating a configuration of a video distribution system according to the present disclosure. [Figure 10] 1 is a diagram illustrating a configuration of a video distribution system according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings indicate the same components.

[0025] (Embodiment 1) The video distribution system of this embodiment is shown in Fig. 1. The video distribution system of this embodiment includes a video source 11, a server 12, a communication network 13, an edge server 14, and a user device 15.

[0026] The server 12 processes the video from the video source 11 into VR (Virtual Reality) video. Specifically, it performs a stitching process to join multiple videos together and a spherical mapping process. Furthermore, it compresses and encodes the VR video and delivers the compressed and encoded VR video to the edge server 14 via the communication network 13.

[0027] The edge server 14 transcodes the compressed and encoded VR video from the server 12 according to the user's viewing situation, and delivers the transcoded VR video to the user device 15. The server 12 and the edge server 14 are connected via a communication network 13. Transcoding refers to converting a compressed video signal into a different format.

[0028] The user device 15 transmits the user's viewing status to the edge server 14 and receives the transcoded VR video from the edge server 14. The user views the VR video via the user device 15.

[0029] In the video distribution system of this embodiment, a hierarchical architecture is applied to the distribution of VR video, in which a server 12 and an edge server 14 are provided between a video source 11 and a user device 15. This reduces the amount of data between the video source 11 and the server 12, thereby realizing low latency in video distribution. Furthermore, the user's quality of experience can be maintained even when the video is transmitted via the edge server 14.

[0030] (Embodiment 2) To transcode the video according to the user's viewing situation, the video is divided into tiles. Figure 2 shows how to divide a 360-degree video into tiles. For a 360-degree video (Figure 2(1)), it can be divided by rows (Figure 2(2)), columns (Figure 2(3)), or rows and columns (Figure 2(4)), or a combination of these (Figure 2(5)). The tile division areas do not all have to be equal. For example, the size of the area can be changed depending on the VR video to be distributed. If the viewing area is limited, the area can be made smaller.

[0031] In the following embodiments, 3 This will be explained using an example of a tile array divided into blocks of 4 rows and columns. 3 Here is an example of a tile array divided into blocks of 4 rows and columns. The tiles are assigned tile numbers t0 to t11. 。

[0032] The video distribution system of this embodiment is shown in Fig. 4. The video distribution system of this embodiment includes a video source 11, a server 12, a communication network 13, an edge server 14, and a user device 15.

[0033] The server 12 processes the video from the video source 11 into a VR (Virtual Reality) video and compresses and encodes it. At this time, The VR video is divided into tiles as shown in FIG. 3. Furthermore, the VR video divided into tiles is distributed to the edge server 14 via the communication network 13. In the example of FIG. 4, the VR video is compressed and encoded at, for example, 12 bpp (bit per pixel). The VR video compressed and encoded at 12 bpp is divided into tiles and distributed to the edge server 14 via the communication network 13.

[0034] The edge server 14 transcodes the VR video divided into tiles from the server 12 according to the user's viewing situation, and delivers the transcoded VR video to the user device.

[0035] The user device 15 transmits the high-priority tile number extracted based on the user's gaze information for the VR video as the viewing situation to the edge server 14. For example, a gaze detection device (not shown) extracts the tile number of the tile at which the user is looking from among the tiles of the VR video as the high-priority tile number, and the user device 15 transmits the extracted high-priority tile number to the edge server 14 as the viewing situation.

[0036] The edge server 14 receives high-priority tile numbers from the user device 15, classifies them into tiles with many high priorities and tiles with few high priorities, and transcodes them. In the example of Figure 4, tiles with many high priorities are encoded at high quality of 12 bpp, and tiles with few high priorities are encoded at low quality of 5 bpp and delivered to the user device 15. VR video encoded at low bpp has a small data volume, allowing video delivery with low delay.

[0037] The number of high priorities is a relative value, and the intention is to divide the level into two according to the number of high priorities. The intention is to encode tiles with more high priorities with higher quality than tiles with fewer high priorities.

[0038] 4, the number of encoding bits is set to 12 bpp and 5 bpp, but these values ​​are merely examples. Also, although there are two levels, there may be three or more levels.

[0039] In the video distribution system of this embodiment, transcoding is performed according to the user's viewing situation, so it is possible to achieve low-delay video distribution while maintaining the quality of experience.

[0040] (Embodiment 3) The video distribution system of this embodiment is shown in Fig. 5. The video distribution system of this embodiment includes a video source 11, a server 12, a communication network 13, an edge server 14, and a user device 15.

[0041] The difference from the second embodiment is that it is the edge server 14, not the server 12, that divides the data into tiles.

[0042] The server 12 processes the video from the video source 11 into VR (Virtual Reality) video and compresses and encodes it. The server 12 then distributes the compressed and encoded VR video to the edge server 14 via a communication network 13. In the example of FIG. 5, the VR video is compressed and encoded at, for example, 12 bpp.

[0043] The edge server 14 divides the compressed and encoded VR video from the server 12 into tiles, transcodes the divided VR video according to the user's viewing situation, and delivers the transcoded VR video to the user device.

[0044] The user device 15 transmits the high-priority tile number extracted based on the user's gaze information for the VR video as the viewing situation to the edge server 14. For example, a gaze detection device (not shown) extracts the tile number of the tile at which the user is looking from among the tiles of the VR video as the high-priority tile number, and the user device 15 transmits the extracted high-priority tile number to the edge server 14 as the viewing situation.

[0045] The edge server 14 receives high-priority tile numbers from the user device 15, classifies them into tiles with many high priorities and tiles with few high priorities, and transcodes them. In the example of Figure 5, tiles with many high priorities are encoded at high quality of 12 bpp, and tiles with few high priorities are encoded at low quality of 5 bpp and delivered to the user device 15. VR video encoded at low bpp has a small data volume, allowing video delivery with low delay.

[0046] The number of high priorities is relative, and the intention is to divide the levels into two according to the number of high priorities. The number of high priorities is relative, and the intention is to encode tiles with more high priorities with higher quality than tiles with fewer high priorities.

[0047] 5, the number of encoding bits is set to 12 bpp and 5 bpp, but these values ​​are merely examples. Also, although there are two levels, there may be three or more levels.

[0048] In the video distribution system of this embodiment, transcoding is performed according to the user's viewing situation, so it is possible to achieve low-delay video distribution while maintaining the quality of experience.

[0049] (Embodiment 4) The video distribution system of this embodiment is shown in Figures 6, 7, and 8. In the video distribution system of this embodiment, the transcoding method and distribution method of the edge server 14 will be described by focusing on the edge server 14 and the user device 15 in the second or third embodiment.

[0050] The user device 15 transmits the high-priority tile numbers extracted based on the user's line-of-sight information to the edge server 14 as viewing conditions. The edge server 14 classifies each tile into levels based on the number of high priorities, and performs transcoding by encoding tiles with many high priorities with high quality and tiles with few high priorities with low quality. The number that determines the high-priority level may be set in advance or may be changed arbitrarily.

[0051] In the examples of Figures 6, 7, and 8, tiles are divided into two levels: tiles with many high priorities and tiles with few high priorities. The tiles with many high priorities are transcoded at high quality, while the tiles with few high priorities are transcoded at low quality. As an example, the union of the "high priority tile numbers" from two user devices 15 is taken. For example, the union of high priority tile numbers t0, t1, t4, t5 and high priority tile numbers t5, t6, t9, t10 is t0, t1, t4, t5, t6, t9, t10. In other words, tiles that either user device 15 has set as high priority are transcoded at high quality with 12 bpp, while tiles that neither user device 15 has set as high priority are transcoded at low quality with 5 bpp.

[0052] 6, 7, and 8, the number of encoding bits is set to 12 bpp and 5 bpp, but these values ​​are merely examples. Also, although there are two levels, there may be three or more levels.

[0053] 6, the edge server 14 unicasts the transcoded common VR video to each user device 15. Unicast distribution enables highly reliable video distribution.

[0054] Therefore, in the video distribution system of this embodiment, highly reliable, low-delay video distribution can be achieved by transcoding and unicasting according to the user's viewing situation.

[0055] 7, the edge server 14 multicasts the transcoded common VR video to each user device 15. Multicast distribution reduces the amount of data, enabling video distribution with low delay.

[0056] Therefore, in the video distribution system of this embodiment, by transcoding and multicasting according to the user's viewing situation, it is possible to achieve highly reliable video distribution with less delay.

[0057] 8, the edge server 14 broadcasts the transcoded common VR video to each user device 15. Broadcast distribution involves a small amount of data and has a small delay since there is no two-way negotiation.

[0058] Therefore, in the video distribution system of this embodiment, video can be distributed with even lower delay by transcoding and broadcasting according to the user's viewing situation.

[0059] (Embodiment 5) 9 and 10 show the video distribution system of this embodiment. In the video distribution system of this embodiment, the transcoding method and distribution method of the edge server 14 will be described by focusing on the edge server 14 and the user device 15 in the second or third embodiment.

[0060] The user device 15 transmits the high-priority tile numbers extracted based on the user's gaze information to the edge server 14 as viewing conditions. The edge server 14 classifies each tile into levels based on the number of high priorities, and performs transcoding by classifying tiles into three or more levels so that tiles with more high priorities are coded with higher quality and tiles with fewer high priorities are coded with lower quality. The number that determines the high-priority level may be set in advance or may be changed arbitrarily.

[0061] Whether there are many or few high priorities is a relative relationship, and the intention is to classify into three or more levels according to the number of high priorities. Whether there are high or low quality is a relative relationship, and the intention is to encode tiles with more high priorities at a higher quality than tiles with fewer high priorities. For example, when classifying into three levels according to the number of high priorities, tiles with a medium number of high priorities are encoded at a medium quality, tiles with a larger number of high priorities are encoded at a higher quality than tiles with a medium number of high priorities, and tiles with a smaller number of high priorities are encoded at a lower quality than tiles with a medium number of high priorities.

[0062] The edge server 14 may also perform transcoding for tiles corresponding to high-priority tile numbers received from the user device 15, in the same way as for tiles with many high priorities, to encode them with higher quality.

[0063] 9 and 10, tiles are divided into three levels: tiles with a larger number of high priorities, tiles with a medium number of high priorities, and tiles with a smaller number of high priorities. The tiles with a larger number of high priorities are transcoded at 12 bpp for high quality, tiles with a medium number of high priorities are transcoded at 5 bpp for medium quality, and tiles with a smaller number of high priorities are transcoded at 3 bpp for low quality. As an example, the intersection and union of the "high priority tile numbers" from two user devices 15 are calculated. For example, the intersection of high priority tile numbers t0, t1, t4, t5 and high priority tile numbers t5, t6, t9, t10 is t5, and the union of high priority tile numbers t0, t1, t4, t5 and high priority tile numbers t5, t6, t9, t10 is t0, t1, t4, t5, t6, t9, t10. In other words, transcoding is performed in which tiles that any user device 15 has set as high priority are encoded at 12 bpp with high quality, tiles that any user device 15 has set as high priority are encoded at 5 bpp with medium quality, and tiles that none of the user devices 15 has set as high priority are encoded at 3 bpp with low quality.

[0064] The edge server 14 also performs transcoding for tiles corresponding to high-priority tile numbers t0, t1, t4, t6, t9, and t10 received from the user device 15, encoding them at high quality at 12 bpp.

[0065] In the examples of FIGS. 9 and 10, the number of encoding bits is divided into three levels: 12 bpp, 5 bpp, and 3 bpp, but it may be divided into four or more levels.

[0066] In the example of Figure 9, the edge server 14 divides the transcoded VR video into tiles coded in high quality, tiles coded in medium quality, and tiles coded in low quality, and distributes the tiles coded in high quality to the user device 15 by multicast, while distributing the other tiles, i.e., the tiles coded in medium quality and the tiles coded in low quality, by unicast to the user device 15. Unicast distribution enables highly reliable video distribution. Multicast distribution reduces the amount of data, enabling video distribution with low latency.

[0067] In addition, the edge server 14 may also perform transcoding at 12 bpp for tiles corresponding to high-priority tile numbers t0, t1, t4, t6, t9, and t10 received from the user device 15, and unicast the tiles to the user device 15 that sent the high-priority tile numbers.

[0068] Therefore, in the video distribution system of this embodiment, by performing transcoding according to the user's viewing situation and combining multicast distribution and unicast distribution, highly reliable, low-delay video distribution is possible.

[0069] In the example of Figure 10, the edge server 14 divides the transcoded VR video into three parts: tiles coded in high quality, tiles coded in medium quality, and tiles coded in low quality, and distributes the tiles coded in high quality to the user device 15 by multicast, tiles coded in medium quality, and tiles coded in low quality to the user device 15 by unicast, and tiles coded in low quality to the user device 15 by broadcast. Unicast distribution enables highly reliable video distribution. Multicast distribution enables video distribution with a small amount of data and low latency. Broadcast distribution reduces the amount of data and has a small latency because there is no two-way negotiation.

[0070] In addition, the edge server 14 may also perform transcoding at 12 bpp for tiles corresponding to high-priority tile numbers t0, t1, t4, t6, t9, and t10 received from the user device 15, and unicast the tiles to the user device 15 that sent the high-priority tile numbers.

[0071] Therefore, in the video distribution system of this embodiment, by transcoding according to the user's viewing situation and combining multicast distribution, unicast distribution, and broadcast distribution, it is possible to achieve highly reliable, low-latency video distribution.

[0072] As described above, according to the present disclosure, it is possible to achieve low latency in video distribution while maintaining the user's quality of experience for the distributed VR video.

[0073] The edge server of the present disclosure can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a communication network. [Explanation of symbols]

[0074] 11:Video source 12: Server 13: Communication Network 14: Edge server 15: User device

Claims

1. an edge server that transcodes the compressed code of the VR video divided into tiles according to the user's viewing situation and delivers the transcoded VR video; a user device that transmits high-priority tile numbers extracted based on the user's line of sight information for the VR video to the edge server and receives the transcoded VR video from the edge server; Equipped with the edge server classifies the tiles into three or more levels and transcodes them according to the viewing status of one or more users so that more tiles with higher priority are coded with higher quality and fewer tiles with lower priority are coded with lower quality; A video distribution system characterized by:

2. an edge server that transcodes the compressed code of the VR video divided into tiles according to the user's viewing situation and delivers the transcoded VR video; a user device that transmits high-priority tile numbers extracted based on the user's line of sight information for the VR video to the edge server and receives the transcoded VR video from the edge server; Equipped with The edge server classifies and transcodes tiles into three or more levels according to the viewing status of one or more users, so that more tiles with higher priority are coded with higher quality and fewer tiles with lower priority are coded with lower quality, and divides the tiles into two at any level. Of the transcoded VR video, the tiles coded with higher quality are distributed by multicast and the other tiles are distributed by unicast. A video distribution system characterized by:

3. an edge server that transcodes the compressed code of the VR video divided into tiles according to the user's viewing situation and delivers the transcoded VR video; a user device that transmits high-priority tile numbers extracted based on the user's line of sight information for the VR video to the edge server and receives the transcoded VR video from the edge server; Equipped with The edge server classifies and transcodes the VR video into three or more levels so that more tiles with higher priority are coded at higher quality and fewer tiles with lower priority are coded at lower quality according to the viewing status of one or more users, divides the VR video into thirds at any level, and distributes the higher quality coded tiles of the transcoded VR video by multicast, distributes the lower quality coded tiles of the transcoded VR video by broadcast, and distributes the remaining medium quality coded tiles of the transcoded VR video by unicast. A video distribution system characterized by:

4. The edge server encodes tiles corresponding to high-priority tile numbers received from the user device with higher quality and unicasts the encoded tiles to the user device that transmitted the high-priority tile numbers.

4. The video distribution system according to claim 1, wherein the video distribution system is a video distribution system for distributing video data.

5. An edge server that transcodes a compressed code of VR video divided into tiles according to a user's viewing situation and delivers the transcoded VR video, receiving a high-priority tile number as the viewing situation; classifying tiles into three or more levels and transcoding them according to the viewing conditions of one or more users so that more tiles with higher priority are coded with higher quality and fewer tiles with lower priority are coded with lower quality; An edge server comprising:

6. An edge server that transcodes a compressed code of VR video divided into tiles according to a user's viewing situation and delivers the transcoded VR video, receiving a high-priority tile number as the viewing situation; According to the viewing conditions of one or more users, tiles with a higher priority are coded at higher quality and tiles with a lower priority are coded at lower quality, and the tiles are transcoded by classifying them into three or more levels, and among the VR video that has been bifurcated and transcoded at any one of the levels, tiles coded at higher quality are distributed by multicast and other tiles are distributed by unicast. An edge server comprising:

7. An edge server that transcodes a compressed code of VR video divided into tiles according to a user's viewing situation and delivers the transcoded VR video, High-priority tile numbers are received as the viewing status, and according to the viewing status of one or more users, tiles are transcoded by classifying them into three or more levels so that more tiles with higher priority are encoded with higher quality and fewer tiles with higher priority are encoded with lower quality, and the VR video is divided into thirds at any one of the levels, and tiles encoded with higher quality among the transcoded VR video are distributed by multicast, tiles encoded with lower quality among the transcoded VR video are distributed by broadcast, and the remaining tiles encoded with medium quality among the transcoded VR video are distributed by unicast. An edge server comprising:

8. A video distribution method for transcoding a compressed code of VR video divided into tiles in accordance with a user's viewing situation and distributing the transcoded VR video, comprising: receiving a high-priority tile number as the viewing situation; classifying tiles into three or more levels and transcoding them according to the viewing conditions of one or more users so that more tiles with higher priority are coded with higher quality and fewer tiles with lower priority are coded with lower quality; A video distribution method comprising:

9. A video distribution method for transcoding a compressed code of VR video divided into tiles in accordance with a user's viewing situation and distributing the transcoded VR video, comprising: receiving a high-priority tile number as the viewing situation; According to the viewing status of one or more users, the tiles are classified into three or more levels so that more tiles with higher priority are coded at higher quality and fewer tiles with higher priority are coded at lower quality, and transcoded, and then divided into two at any level, and of the transcoded VR video, tiles coded at higher quality are distributed by multicast and the other tiles are distributed by unicast. A video distribution method comprising:

10. A video distribution method for transcoding a compressed code of VR video divided into tiles in accordance with a user's viewing situation and distributing the transcoded VR video, comprising: receiving a high-priority tile number as the viewing situation; According to the viewing status of one or more users, the VR video is transcoded by classifying it into three or more levels so that more tiles with higher priority are encoded with higher quality and fewer tiles with higher priority are encoded with lower quality, and the VR video is divided into thirds at any level, and the transcoded tiles encoded with higher quality are distributed by multicast, the transcoded tiles encoded with lower quality are distributed by broadcast, and the remaining tiles encoded with medium quality are distributed by unicast. A video distribution method comprising:

Images