KR102307072B1 - Method and apparatus for outputting video for a plurality of viewpoints - Google Patents

Abstract

In order to output the video, receiving a change request from the user of the user terminal from the current video for the first time to the target video for the second time, calculating a first time based on the current playback time of the current video, Receives the target i-frame of the target video determined by the server based on the first time, and outputs the target video based on the target I-frame.

Description

Video output method and apparatus for a plurality of viewpoints {METHOD AND APPARATUS FOR OUTPUTTING VIDEO FOR A PLURALITY OF VIEWPOINTS}

The following embodiments relate to a technology for outputting a video from a user terminal, and more specifically, to a technology for outputting a video for a plurality of viewpoints.

Referring to FIG. 1 , content providing a plurality of viewpoints to a user may be provided. For example, a plurality of moving images 121 , 122 , and 123 for each of a plurality of viewpoints provided by the content may be generated and provided. Although the plurality of videos 121, 122 and 123 for a part of the same scene that the user 100 can see from the viewpoint of the user 110 is shown, the plurality of videos may relate to different scenes. have. However, the plurality of moving images 121 , 122 and 123 are temporally synchronized with each other. Accordingly, when the user 110 views the moving image 121 and then switches to the moving image 122 , the moving image 122 may be provided after the elapsed playback time of the moving image 121 . Since it is important that the plurality of videos 121, 122, and 123 are provided to the user 100 in synchronization with each other in time, when the user 100 switches the video between the plurality of videos 121, 122 and 123 , the minimum possible delay time is required.

An embodiment may provide a method and an apparatus for outputting a video for a plurality of viewpoints.

An embodiment may provide a method and apparatus for providing a second viewpoint to a user by outputting a target video from a current video for the first viewpoint.

According to an aspect, a method of outputting a video performed by a user terminal includes: receiving a change request from a user of the user terminal from a current video for a first viewpoint to a target video for a second viewpoint; Calculating a first time based on the current playback time of the current video, transmitting the first time to a server providing the target video, the target video determined by the server based on the first time Receiving a target I (I)-frame of, and outputting the target video based on the target I (I)-frame.

The current video includes a first segment for a first section of the current video, and the target video includes a target segment for a second section of the target video that is the same section as the first section, and the target segment may include the target I-frame.

Receiving the target I-frame may include receiving frames after the target I-frame among frames of the target segment.

Calculating the first time may include calculating the first time based on the current playback time, an initial processing time of the target video, and an initial playback buffer time.

The target I-frame may be determined by the server based on a round trip time (RTT) of data between the user terminal and the server and a target time calculated based on the first time.

The target I-frame may be an I-frame of the target video closest to the target time.

Calculating the first time may include: the first time based on the current playback time, a round-trip time (RTT) of data between the user terminal and the server, an initial processing time of the target video, and an initial playback buffer time It may include the step of calculating

The target I-frame may be an I-frame of the target video closest to the first time.

According to another aspect, the user terminal includes a memory in which a program for outputting a video is recorded, and a processor for executing the program, wherein the program is a current video for a first viewpoint from a user of the user terminal Receiving a change request to a target video for a second time from, calculating a first time based on a current playback time of the current video, and transmitting the first time to a server providing the target video step, receiving a target i-frame of the target video determined by the server based on the first time, and outputting the target video based on the target i-frame carry out

According to another aspect, a method for providing a video to a user terminal performed by a server receives a request for transmission of a target video for a second viewpoint from a user terminal that outputs a current video for a first viewpoint - The transmission request includes a first time calculated by the user terminal based on the current playback time of the current video -, based on the first time, the target i (I)-frame of the target video determining , and transmitting the target I-frame to the user terminal.

The current video includes a first segment for a first section of the current video, and the target video includes a target segment for a second section of the target video that is the same section as the first section, and the target segment may include the target I-frame.

The transmitting of the target I-frame may include transmitting frames after the target I-frame among frames of the target segment to the user terminal.

The first time may be calculated by the user terminal based on the current playback time, an initial processing time of the target video, and an initial playback buffer time.

The determining of the target I-frame includes calculating a target time based on a round trip time (RTT) and the first time between the user terminal and the server, and at the target time. determining the target I-frame based on the

The determining of the target I-frame based on the target time may include determining an I-frame of the target video closest to the target time as the target I-frame.

The first time may be calculated by the user terminal based on the current playback time, a round-trip time (RTT) of data between the user terminal and the server, an initial processing time of the target video, and an initial playback buffer time .

The determining of the target I-frame may include determining an I-frame of the target video closest to the first time as the target I-frame.

According to another aspect, the server includes a memory in which a program for providing a video is recorded, and a processor for executing the program, wherein the program is a user terminal outputting a current video for a first viewpoint Receiving a transmission request of a target video for a second time point from - The transmission request includes a first time calculated by the user terminal based on the current playback time of the current video - at the first time Determining a target I-frame of the target video based on the step, and performing the steps of transmitting the target I-frame to the user terminal.

1 illustrates a plurality of videos for a plurality of viewpoints according to an example.
2 illustrates methods for transmitting a plurality of videos to a user terminal according to an example.
3 illustrates a video providing system according to an embodiment.
4 illustrates an existing method and an improved method of outputting a video of a new viewpoint according to an example.
5 is a block diagram of a user terminal according to an embodiment.
6 is a configuration diagram of a server according to an embodiment.
7 is a signal flow diagram of a video output method according to an embodiment.
8 is a timeline of a method of outputting a video of a new viewpoint according to an example.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these examples. Like reference numerals in each figure indicate like elements.

Various modifications may be made to the embodiments described below. It should be understood that the embodiments described below are not intended to limit the embodiments, and include all modifications, equivalents or substitutes thereto.

Terms used in the examples are only used to describe specific examples, and are not intended to limit the examples. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiment belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

In addition, in the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and the overlapping description thereof will be omitted. In the description of the embodiment, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

2 illustrates methods for transmitting a plurality of videos to a user terminal according to an example.

According to one aspect, the content provides a plurality of moving images 210 , 220 , and 230 . For example, the content may be a game, and each of the plurality of moving images 210 , 220 and 230 may be temporally synchronized moving images. As another example, the content may be real-time content such as sports broadcasting, and the plurality of moving images 210 , 220 and 230 may be moving images captured by respective cameras.

Each of the plurality of videos 210 , 220 , and 230 may consist of a plurality of segments. The segment 211 of the first video 210 , the segment 221 of the second video 220 , and the segment 231 of the third video 230 may correspond to the same time period. For example, if the video 210 is a video of a total of 20 seconds, and the video 210 includes 5 segments corresponding to a 4 second section, the first segment 211 is a 0 second to 4 second section of the content. can be In the above example, the segment 221 of the video 220 and the segment 231 of the video 230 may be 0 seconds to 4 seconds of content, which is the same time interval as the segment 211 .

In order to output content from the user terminal, a plurality of videos 210 to 230 are transmitted from the server to the user terminal.

The first method 250 is a method in which the server generates a stream for each of a plurality of videos 210 to 230 and transmits the plurality of streams to the user terminal in parallel.

The second method 260 is a method in which the server generates segments of the plurality of moving images 210 to 230 as one stream and transmits the stream to the user terminal.

The third method 270 is a method in which the server generates segments corresponding to time intervals as one tile, generates the generated tiles as one stream, and transmits the stream to the user terminal.

first method (250) second method (260) third method (270) sync speed Slow (terminal) Normal (Server) Fast (Server) download speed speed commonly commonly storage usage commonly height height Use NW commonly height height scalability height Normal (VOD)
Low (Live) Normal (VOD)
Low (Live) number of streams N One One number of videos N N One Applications Switch video and play Play multiple videos at a time Multiple video playback, VR

Among the methods 250 to 270 , the first method 250 may be more flexible and efficient than the other methods 260 and 270 in a network situation and the like. Accordingly, in the following description, a method of providing a plurality of moving images may be a method using the first method 250 , but is not limited to the described embodiment.

3 illustrates a video providing system according to an embodiment.

According to one aspect, the video providing system 300 includes a server 310 that provides a plurality of videos of content and a user terminal 320 that outputs a video to a user.

The server 310 may generate a plurality of videos for the content. For example, the content may be a game used by the user of the user terminal 320 , and as another example, the content may be a real-time relay program captured by a plurality of cameras.

Hereinafter, a method for a server to provide a video to a user terminal and a method for the user terminal to output a video will be described in detail with reference to FIGS. 4 to 8 .

4 illustrates an existing method and an improved method of outputting a video of a new viewpoint according to an example.

The user may switch the video output from the user terminal from the first video of the first view to the second video of the second view. For example, based on the segment 411 of the first video having a period of 4 to 8 seconds, a video conversion may be requested at the request time 401 while the first video is output.

In the first method, in the above case, the user terminal receives the segment 431 of the second video corresponding to the segment 411 , and the segment corresponding to the current playback time at the time 402 at which the segment 431 is received. A section of (431) may be output. In this case, data corresponding to the past section 432 of the segment 431 may be useless because it corresponds to data in the past based on the current playback time. In addition, time and resources for receiving data corresponding to the past section 432 may delay the output of the second video.

In contrast, the second method predicts a time point 402 at which the segment 441 is received in the above case, and the user terminal receives the segment 441 of the second video after the time point 402, so that the first method It prevents reception of data corresponding to the past section 432 as shown in FIG. The segment 441 may be data remaining in the segment 431 excluding data corresponding to the past section 432 . By transmitting and receiving only data necessary for output, the output delay time of the second video may be reduced.

Hereinafter, with reference to FIGS. 5 to 8 , the contents related to the second method will be described in detail.

5 is a configuration diagram of a user terminal according to an embodiment.

The user terminal 500 includes a communication unit 510 , a processor 520 , and a memory 530 . For example, the user terminal 500 may be the user terminal 320 described with reference to FIG. 3 . The user terminal 500 may include a mobile terminal such as a personal computer (PC) and a smart phone, and is not limited to the described embodiment.

The communication unit 510 is connected to the processor 520 and the memory 530 to transmit and receive data. The communication unit 510 may be connected to another external device to transmit/receive data. Hereinafter, the expression "transmitting and receiving "A" may indicate transmitting and receiving "information or data representing A".

The communication unit 510 may be implemented as circuitry in the user terminal 500 . For example, the communication unit 510 may include an internal bus and an external bus. As another example, the communication unit 510 may be an element that connects the user terminal 500 and an external device. The communication unit 510 may be an interface. The communication unit 510 may receive data from an external device and transmit the data to the processor 520 and the memory 530 .

The processor 520 processes data received by the communication unit 510 and data stored in the memory 530 . A “processor” may be a data processing device implemented in hardware having circuitry having a physical structure for performing desired operations. For example, desired operations may include code or instructions included in a program. For example, a data processing device implemented as hardware includes a microprocessor, a central processing unit, a processor core, a multi-core processor, and a multiprocessor. , an Application-Specific Integrated Circuit (ASIC), and a Field Programmable Gate Array (FPGA).

Processor 520 executes computer readable code (eg, software) stored in memory (eg, memory 530 ) and instructions issued by processor 520 .

The memory 530 stores data received by the communication unit 510 and data processed by the processor 520 . For example, the memory 530 may store a program (or an application, software). The stored program may be a set of syntaxes that are coded so as to output a moving picture and are executable by the processor 520 .

According to one aspect, memory 530 may include one or more volatile memory, non-volatile memory and random access memory (RAM), flash memory, hard disk drive, and optical disk drive.

The memory 530 stores a set of instructions (eg, software) for operating the user terminal 500 . The instruction set for operating the user terminal 500 is executed by the processor 520 .

The communication unit 510 , the processor 520 , and the memory 530 will be described in detail below with reference to FIGS. 7 to 8 .

6 is a configuration diagram of a server according to an embodiment.

The server 600 includes a communication unit 610 , a processor 620 , and a memory 630 . For example, the server 600 may be the server 310 described with reference to FIG. 3 .

The communication unit 610 is connected to the processor 620 and the memory 630 to transmit and receive data. The communication unit 610 may be connected to another external device to transmit/receive data.

The communication unit 610 may be implemented as a circuit network in the server 600 . For example, the communication unit 610 may include an internal bus and an external bus. As another example, the communication unit 610 may be an element that connects the server 600 and an external device. The communication unit 610 may be an interface. The communication unit 610 may receive data from an external device and transmit the data to the processor 620 and the memory 630 .

The processor 620 processes data received by the communication unit 610 and data stored in the memory 530 . Processor 620 executes computer readable code (eg, software) stored in memory (eg, memory 630 ) and instructions issued by processor 620 .

The memory 630 stores data received by the communication unit 610 and data processed by the processor 620 . For example, the memory 630 may store a program (or an application, software). The stored program may be a set of syntax that is coded so as to provide a moving picture to the user terminal 500 and is executable by the processor 620 .

According to one aspect, memory 630 may include one or more of volatile memory, non-volatile memory and RAM, flash memory, hard disk drive, and optical disk drive.

The memory 630 stores an instruction set (eg, software) for operating the server 600 . The set of instructions for operating the server 600 is executed by the processor 620 .

The communication unit 610 , the processor 620 , and the memory 630 will be described in detail below with reference to FIGS. 7 to 8 .

7 is a signal flow diagram of a video output method according to an embodiment.

The following steps 710 to 770 are performed by the user terminal 500 and the server 600 described above.

In step 710 , the user terminal 500 receives a request for changing the viewpoint of the video output from the user terminal 500 from the user of the user terminal 500 . For example, the user terminal 500 is a second video (hereinafter, referred to as a “target video”) while a first video (hereinafter, referred to as “current video”) is being output from the user terminal 500 . ) can receive an output request. The current video may be a video generated based on a first view, and the target video may be a video generated based on a second view that is different from the first view.

The content may be composed of a plurality of videos including a current video and a target video. For example, a plurality of videos may include the same time period. Each of the plurality of videos may consist of a plurality of segments. A detailed description of the plurality of segments may be replaced with the description described above with reference to FIG. 2 .

According to an aspect, when the current video is changed to the target video, the playback start time of the target video may be determined based on the current time of the current video. For example, if the content is a sports broadcast and the current video shot with the first camera is changed to the target video shot with the second camera, the playback end time of the current video and the playback start time of the target video are the same or at least There must be a delay time. The delay time may correspond to the time to prepare the playback of the target video.

In step 720, the user terminal 500 calculates the first time based on the current playback time. The current playback time may be a playback end time of the current video or a time when a viewpoint change request is received from the user. The first time may be a time used to determine a playback start time of a target video to be output. For example, the first time may be a time in consideration of a round-trip time (RTT) of data between the user terminal 500 and the server 600 .

According to an aspect, the user terminal 500 may calculate the first time based on the current playback time, the initial processing time of the target video, and the initial playback buffer time. The initial processing time of the target video may include a decoding time and rendering time of the video. The initial playback buffer time may be a buffering time for the user terminal 500 to output the target video. Since the RTT between the user terminal 500 and the server 600 is not considered for the first time calculated by the above method, the RTT may be considered on the side of the server 600 receiving the first time.

According to another aspect, the user terminal 500 may calculate the first time based on the current playback time, the RTT between the user terminal 500 and the server 600, the initial processing time of the target video, and the initial playback buffer time. . The RTT may be calculated based on the actual round-trip time of data between the user terminal 500 and the server 600 . The RTT may include a time for processing the target video in the server 600 (eg, video encoding time).

In step 730 , the user terminal 500 transmits the calculated first time to the server 600 .

In step 740, the server 600 determines a target frame of the target video based on the first time. The determined target frame may be the first frame of the target video to be output from the user terminal 500 . For example, the target frame may be an I-frame, but is not limited thereto, and may be a non-(B)-frame or a P(P)-frame.

Specifically, the server 600 may calculate the playback start time of the target video based on the first time. The playback start time of the target video may be referred to as a target time. The server 600 determines the target I-frame based on the target time. For example, an I-frame of a target moving picture closest to the target time in the future may be determined as the target I-frame. The segment including the frame corresponding to the target time may be a target segment.

To determine the target I-frame, the time of group of pictures (GOP) may be considered. For example, GOP/2 to GOP+GOP/2 times may be considered to determine the target I-frame.

According to one aspect, when the first time is calculated by the user terminal 500 based on the current playback time, the initial processing time of the target video, and the initial playback buffer time, the server 600 includes the user terminal 500 and the server A target time may be calculated based on the RTT between 600 and the first time.

According to another aspect, the first time is calculated by the user terminal 500 based on the current playback time, the RTT between the user terminal 500 and the server 600, the initial processing time of the target video, and the initial playback buffer time. In this case, the server 600 may determine the first time as the target time.

The current video includes a first segment for a first section including the current playback time, the target video includes a target segment for a second section of the target video that is the same section as the first section, and the target segment includes target I - May contain frames.

In step 750 , the server 600 transmits the target frame to the user terminal 500 . For example, the transmitted target frame may be an I-frame.

According to one aspect, the server 600 may transmit frames after the target I-frame among frames of the target segment including the target I-frame to the user terminal 500 . In other words, among the frames of the target segment, previous frames of the target I-frame may not be transmitted to the user terminal 500 . By preventing the transmission of frames that are not output from the user terminal 500, a delay time caused by this can be reduced.

In step 760, the user terminal 500 processes the target video based on the target frame. For example, the user terminal 500 may encode or render a target video.

In step 770 , the user terminal 500 outputs a target video. For example, the target video may be output after being buffered.

8 is a timeline of a method of outputting a video of a new viewpoint according to an example.

At time 801 , the user terminal 500 receives a video conversion request from the user, calculates a first time, and transmits the calculated first time to the server 600 .

At time 802 , server 600 receives a first time from user terminal 500 . _{The difference T LR} between time 802 and time 801 may be part of the RTT.

The server 600 may _{determine a target frame during the T SP} and process data to be transmitted to the user terminal 500 . For example, a target segment of a target video including the target frame may be encoded. T _SP may be part of RTT.

At time 803 , the server 600 transmits the target frame to the user terminal 500 .

At time 804 , the user terminal 500 receives the target frame from the server 600 . _{The difference T LT} between time 803 and time 804 may be part of the RTT. The difference between time 801 and time 804 may be an RTT.

The user terminal 500 may process and buffer the target frame during _{T UP.} For example, the target frame may be decoded and rendered.

At time 805 , the user terminal 500 may output a target video based on the target frame. At least one of the user terminal 500 and the server 600 predicts a difference between the time 801 and the time 805 so that the user terminal 500 can smoothly output the video by changing the viewpoint. In addition, the difference between the time 801 and the time 805 can also be reduced because not all of the target segment is transmitted, but only a part of the target segment is transmitted.

The device described above may be implemented as a hardware component, a software component, and/or a combination of the hardware component and the software component. For example, devices and components described in the embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), It may be implemented using one or more general purpose or special purpose computers, such as a programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For convenience of understanding, although one processing device is sometimes described as being used, one of ordinary skill in the art will recognize that the processing device includes a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that can include For example, the processing device may include a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as parallel processors.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic such as floppy disks. - includes magneto-optical media, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with reference to the limited embodiments and drawings, various modifications and variations are possible from the above description by those skilled in the art. For example, the described techniques are performed in a different order than the described method, and/or the described components of the system, structure, apparatus, circuit, etc. are combined or combined in a different form than the described method, or other components Or substituted or substituted by equivalents may achieve an appropriate result.

500: user terminal
600: server

Claims (20)

A method of outputting a video performed by a user terminal,
Receiving a change request from a user of a user terminal from a current video for a first viewpoint to a target video for a second viewpoint, wherein the current video includes a first segment for a first section of the current video and the target video includes a target segment for a second section of the target video that is the same section as the first section, and the first segment and the target segment are pre-encoded by a server;
calculating a first time based on a current playback time of the current video;
transmitting the first time to the server providing the target video;
receiving a partial segment of the target segment including a target i-frame of the target video determined by the server based on the first time, the partial segment being the target of the frames of the target segment I (I) - does not include frames before the frame -; and
outputting the target video based on the target i-frame of the partial segment
including,
Calculating the first time comprises:
Calculating the first time based on the current playback time, a round trip time (RTT) of data between the user terminal and the server, an initial processing time of the partial segment, and an initial playback buffer time
containing,
How to output video.
delete delete delete According to claim 1,
the target I-frame is determined by the server based on a target time calculated based on the first time;
How to output video.
6. The method of claim 5,
The target I (I)-frame is the I-frame of the target video closest to the target time,
How to output video.
delete delete A computer-readable recording medium storing a program for performing the method of any one of claims 1, 5, and 6.
The user terminal is
a memory in which a program for outputting a moving picture is recorded; and
a processor that executes the program
including,
The program is
Receiving a change request from a user of a user terminal from a current video for a first viewpoint to a target video for a second viewpoint, wherein the current video includes a first segment for a first section of the current video and the target video includes a target segment for a second section of the target video that is the same section as the first section, and the first segment and the target segment are pre-encoded by a server;
calculating a first time based on a current playback time of the current video;
transmitting the first time to the server providing the target video;
receiving a partial segment of the target segment including a target i-frame of the target video determined by the server based on the first time; and
Outputting the target video based on the target i (I)-frame of the partial segment
do,
Calculating the first time comprises:
Calculating the first time based on the current playback time, a round trip time (RTT) of data between the user terminal and the server, an initial processing time of the target video, and an initial playback buffer time
containing,
user terminal.
A method of providing a video to a user terminal performed by a server,
Receiving a transmission request for a target video for a second viewpoint from a user terminal that outputs a current video for a first viewpoint - The transmission request is performed by the user terminal based on the current playback time of the current video including a calculated first time, the current video includes a first segment for a first section of the current video, and the target video includes a second section of the target video that is the same section as the first section a target segment, wherein the first segment and the target segment are pre-encoded by a server;
determining a target i-frame of the target segment of the target video based on the first time; and
transmitting a partial segment of the target segment including the target I-frame to the user terminal, wherein the partial segment does not include frames before the target i-frame among frames of the target segment;
including,
The first time is determined by the user terminal based on the current playback time, a round trip time (RTT) of data between the user terminal and the server, an initial processing time of the partial segment, and an initial playback buffer time. calculated,
How to provide a video.
delete delete delete 12. The method of claim 11,
Determining the target I (I)-frame comprises:
calculating a target time based on the first time; and
determining the target eye (I)-frame based on the target time
containing,
How to provide a video.
16. The method of claim 15,
Determining the target eye (I)-frame based on the target time,
determining an i-frame of the target video closest to the target time as the target i-frame
containing,
How to provide a video.
delete 12. The method of claim 11,
Determining the target I (I)-frame comprises:
determining an i-frame of the target video closest to the first time as the target i-frame
containing,
How to provide a video.
A computer-readable recording medium storing a program for performing the method of any one of claims 11, 15, 16 and 18.
server,
a memory in which a program for providing a moving picture is recorded; and
a processor that executes the program
including,
The program is
Receiving a transmission request for a target video for a second viewpoint from a user terminal that outputs a current video for a first viewpoint - The transmission request is performed by the user terminal based on the current playback time of the current video including a calculated first time, the current video includes a first segment for a first section of the current video, and the target video includes a second section of the target video that is the same section as the first section a target segment, wherein the first segment and the target segment are pre-encoded by a server;
determining a target i-frame of the target segment of the target video based on the first time; and
transmitting a partial segment of the target segment including the target I-frame to the user terminal, wherein the partial segment includes frames of the target segment before the target I-frame not -
do,
The first time is determined by the user terminal based on the current playback time, a round trip time (RTT) of data between the user terminal and the server, an initial processing time of the partial segment, and an initial playback buffer time. calculated,
server.

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