JP2020170887A - Receiving terminal, retransmission server, and receiving program - Google Patents

Abstract

To provide a receiving terminal, a retransmission server, and a receiving program that can continue stable video reproduction even when a communication environment deteriorates in video distribution using inter-terminal communication.SOLUTION: A receiving terminal 30 includes a segment receiving unit 34 that receives some video segments from a distribution server 10 and the remaining video segments from another receiving terminal 30, a segment transmitting unit 35 that transmits some video segments to the other receiving terminal 30, a segment reproduction unit 36 that reproduces a series of received video segments, an inter-terminal communication monitoring unit 32 that detects the non-delivery of the video segment transmitted to the other receiving terminal 30, and a distribution instruction unit 33 that notifies a retransmission server 20 of the distribution instruction specifying identification information of each of the other receiving terminals 30 and a video segment number when the non-delivery of the video segment is detected, and the segment receiving unit 34 further receives the video segment transmitted from the retransmission server 20 to the own terminal.SELECTED DRAWING: Figure 7

Description

The present invention relates to a receiving terminal, a retransmission server, and a receiving program for video distribution.

Conventionally, in video distribution via the Internet, adaptive streaming methods such as HLS (HTTP Live Streaming) and MPEG-DASH (MPEG Dynamic Adaptive Streaming over HTTP) that dynamically change the quality of video according to the network congestion status. Is commonly used.

On the other hand, as a communication means for video distribution, in addition to the Internet, there is a method of exchanging data by inter-terminal communication (see, for example, Non-Patent Document 1). By utilizing the communication between terminals, it is possible to avoid the influence of the decrease in the available bandwidth due to the congestion of the Internet or the congestion of the cache server.

Achieved expansion of large-capacity communication area by terminal-to-terminal communication in the 5G era, May 21, 2018, KDDI R & D Laboratories, Inc., Internet <https: // www. KDDI-research. jp / newrelease / 2018/052102. html>

Generally, wireless communication such as Wi-Fi (registered trademark) Direct or Bluetooth (registered trademark) is used for communication between terminals, and radio waves around the terminal are used as compared with wired communication such as Ethernet (registered trademark). Throughput may decrease or communication may be disconnected due to the influence of the environment. When the throughput dropped significantly, even if the adaptive streaming method was adopted, the lowest quality video could not be delivered and the playback might be stopped. In addition, when the communication is disconnected, the playback is stopped because the moving image data cannot be acquired.

An object of the present invention is to provide a receiving terminal, a retransmission server, and a receiving program capable of stably continuing video reproduction even when the communication environment deteriorates in video distribution using inter-terminal communication.

The receiving terminal according to the present invention receives a part of the segments distributed from the distribution server among the series of segments constituting the moving image, and shares and reproduces the series of segments within the group by inter-terminal communication. A receiving unit that receives a part of the segment from the distribution server and the remaining segment from another receiving terminal in the group, and a transmission that transmits the part of the segment to the other receiving terminal. A unit, a reproduction unit that sequentially reproduces the received series of segments according to the segment number, a detection unit that detects the non-delivery of the segment transmitted to the other receiving terminal, and the non-delivery of the segment are detected. Correspondingly, it is provided with a first distribution instruction unit that notifies the retransmission server of the identification information of each of the other receiving terminals that are the transmission destinations of the segment and the distribution instruction that specifies the number of the segment. The receiving unit further receives the segment transmitted from the retransmission server to the own terminal in response to the distribution instruction.

In response to a request to leave the group, the receiving terminal receives identification information of the own terminal and the other receiving terminals to which the partial segment is transmitted, and the partial segment to be transmitted by the own terminal. A second distribution instruction unit may be provided to notify the retransmission server of the distribution instruction including the number of.

The withdrawal request may occur when the remaining segment is not received from the other receiving terminal for a predetermined time.

The retransmission server according to the present invention is connected to a plurality of receiving terminals that reproduce a series of segments constituting a moving image by sharing a part of the segments distributed from the distribution server within the group by inter-terminal communication. In response to the detection of non-delivery of a segment transmitted to another receiving terminal in the group by the receiving terminal, instruction reception for receiving the identification information of the other receiving terminal and the delivery instruction specifying the number of the segment A unit, a storage unit that stores the series of segments common to the distribution server, and a transmission unit that transmits the segment of the number specified by the distribution instruction to the other receiving terminal in response to the distribution instruction. , Equipped with.

The receiving program according to the present invention receives a part of the segments distributed from the distribution server among the series of segments constituting the moving image, and shares and reproduces the series of segments within the group by inter-terminal communication. A receiving step of receiving the partial segment from the distribution server and the remaining segment from another receiving terminal in the group to the terminal, and a transmitting step of transmitting the part of the segment to the other receiving terminal. , A reproduction step of sequentially reproducing the received series of segments according to the number of the segment, a detection step of detecting non-delivery of the segment transmitted to the other receiving terminal, and detection of non-delivery of the segment. In response to the above, the first distribution instruction step of notifying the retransmission server of the identification information of each of the other receiving terminals to which the segment is transmitted and the distribution instruction specifying the number of the segment is executed. In the reception step, the segment to be transmitted from the retransmission server to the own terminal is further received in response to the distribution instruction.

According to the present invention, in video distribution using inter-terminal communication, stable video playback can be continued even when the communication environment deteriorates.

The overall configuration of the distribution system according to the embodiment is shown. It is a figure which shows the functional structure of the distribution server which concerns on embodiment. It is a figure which illustrates the operation flow at the time of constructing the receiving terminal group which concerns on embodiment. It is a figure which shows the distribution example of the moving image segment to be distributed from the distribution server to the receiving terminal which concerns on embodiment. It is a figure which illustrates the relationship of transmission and reception of the moving image segment by the terminal-to-terminal communication which concerns on embodiment. It is a figure which shows the functional structure of the retransmission server which concerns on embodiment. It is a figure which shows the functional structure of the receiving terminal which concerns on embodiment. It is a figure which shows the operation flow of the distribution system when the communication between terminals which concerns on embodiment is disconnected. It is a figure which illustrates the flow of the distribution of the moving image segment when the communication between terminals which concerns on embodiment is disconnected. It is a figure which illustrates the flow of the generation of the withdrawal request from a receiving terminal group with the disconnection of the communication between terminals which concerns on embodiment. It is a figure which illustrates the flow of the distribution of the moving image segment when the receiving terminal which concerns on embodiment leaves a receiving terminal group. It is a figure which illustrates the flow of the distribution of the moving image segment before and after the receiving terminal group which concerns on embodiment is reconstructed.

Hereinafter, an example of the embodiment of the present invention will be described.
The system of the present embodiment is a stream-sharing video distribution system that reduces the influence of congestion on the Internet or a server by sharing a video stream received by a terminal with other terminals in the group by communication between terminals.

FIG. 1 shows the overall configuration of the distribution system 1 according to the present embodiment.
In the present embodiment, a case where a single quality video data is distributed will be described, but the distribution system 1 distributes a plurality of quality video data such as high quality, medium quality, and low quality by an adaptive streaming method. May be good.

The distribution server 10 stores segmented video data, and distributes the video via the Internet, a mobile carrier network, or a mobile base station in response to a request from the receiving terminal 30. Further, the distribution server 10 holds the address information (for example, URL or IP address) of the retransmission server 20, and distributes a segmented copy of the moving image data to the retransmission server 20.

The retransmission server 20 holds the address information of the distribution server 10, and acquires and stores a copy of the segmented moving image data from the distribution server 10. Then, the retransmission server 20 transfers the video segment of the copy of the video data acquired from the distribution server 10, which should have been transferred by inter-terminal communication within the group of the receiving terminals 30, but has not been delivered to the mobile carrier. It is delivered to the receiving terminal 30 on the receiving side of the inter-terminal communication that has not been delivered via the network or the mobile base station.
Compared with the case of distribution from the distribution server 10 via the Internet, the distribution from the retransmission server 20 is performed at a higher speed because it does not go through the Internet.

The mobile carrier network transfers the route for transferring the video data distributed from the distribution server 10 via the Internet to the mobile base station, and the video data distributed from the retransmission server 20 in the mobile carrier network to the mobile base station. It is a network that includes a route for.
In the mobile carrier network, a network switch for allocating a route from the distribution server 10 and a route from the retransmission server 20 and a retransmission server 20 are arranged.

The mobile base station transmits the moving image data transferred from the mobile carrier network to the receiving terminal 30 by wireless communication.

The receiving terminal group is composed of a plurality of receiving terminals 30. As an example, in the figure, a group composed of three receiving terminals 30A, 30B, and 30C is shown, but the number of receiving terminals 30 is not limited to this.

FIG. 2 is a diagram showing a functional configuration of the distribution server 10 according to the present embodiment.
The distribution server 10 includes a group management unit 11, a segment determination unit 12, a segment storage unit 13, and a segment transmission unit 14.

The group management unit 11 constructs a receiving terminal group in response to a request from the receiving terminal 30, for example, according to an operation flow described later (FIG. 3).

The segment determination unit 12 determines the receiving terminal 30 which is the transmission destination of the moving image segment and the moving image segment to be transmitted according to the configuration of the receiving terminal group managed by the group management unit 11.

The segment storage unit 13 stores the segmented moving image data, and provides the corresponding moving image segment in response to the request from the segment transmitting unit 14.

The segment transmission unit 14 transmits the moving image segment determined by the segment determination unit 12 among the segmented moving image data stored in the segment storage unit 13 to the receiving terminal 30 of the transmission destination.

FIG. 3 is a diagram illustrating an operation flow when a receiving terminal group is constructed by the group management unit 11 of the distribution server 10 according to the present embodiment.
Here, as an example, a case where the receiving terminal 30A takes the lead and three receiving terminals 30A, 30B, and 30C form a receiving terminal group will be described.

In step S1, the distribution server 10 receives a request for building a receiving terminal group from the receiving terminal 30A.

In step S2, the distribution server 10 issues a group ID and notifies the receiving terminal 30A that has requested the construction of the receiving terminal group. The group ID may be, for example, a 4-digit number. Further, it is desirable that the group ID is provided with a time limit (lifetime) such as 1 minute.
The issued group ID is notified from the receiving terminal 30A to the receiving terminals 30B and 30C.

In step S3, the distribution server 10 receives the notification of the group ID from the receiving terminals 30B and 30C.

In step S4, the distribution server 10 constructs a receiving terminal group including the receiving terminal 30A that has notified the group ID in step S2 and the receiving terminals 30B and 30C that have notified the same group ID.

FIG. 4 is a diagram showing an example of distribution of moving image segments to be distributed from the distribution server 10 to the receiving terminal 30 according to the present embodiment.
Here, an example is shown in which a round robin method is adopted for distribution to a group consisting of three receiving terminals 30 (30A, 30B, 30C).

A moving image segment number is sequentially assigned to each receiving terminal 30, for example, as follows.
Receiving terminal 30A: Video segment number 3N-2; N: Natural number Receiving terminal 30B: Video segment number 3N-1; N: Natural number Receiving terminal 30C: Video segment number 3N; N: Natural number

The moving image segment numbers acquired by the receiving terminals 30A, 30B, and 30C are examples, and may be a method other than the round robin method. Further, the algorithm for determining the moving image segment number may be changed according to the number of receiving terminals 30.

FIG. 5 is a diagram illustrating a relationship between transmission and reception of a moving image segment by inter-terminal communication according to the present embodiment.
This example shows the moving image segments transmitted and received by the inter-terminal communication when the moving image segments shown in FIG. 4 are sorted.

The receiving terminal 30A transmits the video segment having the number 3N-2 received from the distribution server 10 to the receiving terminals 30B and 30C, and also receives the video segment having the number 3N-1 from the receiving terminal 30B to receive the video segment having the number 3N-1 from the receiving terminal 30C. Receives a video segment with a number of 3N from.
By performing the same transmission and reception processing on the receiving terminals 30B and 30C, the receiving terminals 30A, 30B, and 30C can acquire all the series of moving image segments, respectively.

FIG. 6 is a diagram showing a functional configuration of the retransmission server 20 according to the present embodiment.
The retransmission server 20 includes a distribution instruction receiving unit 21 (instruction receiving unit), a segment determining unit 22, a segment storage unit 23 (accumulation unit), and a segment transmitting unit 24 (transmitting unit).

The distribution instruction receiving unit 21 indicates that the video segment transmitted by itself for sharing within the group has not reached the other terminal due to the disconnection of communication between terminals or a large delay in the receiving terminal group. The delivery instruction transmitted from the detected receiving terminal 30 is received.

The segment determination unit 22 determines the receiving terminal 30 which is the transmission destination of the moving image segment and the moving image segment to be transmitted according to the content of the distribution instruction acquired by the distribution instruction receiving unit 21.

The segment storage unit 23 stores segmented moving image data common to the distribution server 10, and provides the corresponding moving image segment in response to a request from the segment transmitting unit 24.

The segment transmission unit 24 transmits the moving image segment determined by the segment determination unit 22 among the segmented moving image data stored in the segment storage unit 23 to the receiving terminal 30 of the transmission destination.

Each time the retransmission server 20 receives a distribution instruction from any of the receiving terminals 30, the retransmission server 20 sends the video segment undelivered in the inter-terminal communication to the receiving terminal 30 on the receiving side in response to the distribution instruction. Deliver over a wider and lower latency network.

FIG. 7 is a diagram showing a functional configuration of the receiving terminal 30 according to the present embodiment.
The receiving terminal 30 includes a group building unit 31, an inter-terminal communication monitoring unit 32 (detection unit), a distribution instruction unit 33 (first distribution instruction unit), a segment reception unit 34 (reception unit), and a segment transmission unit. It includes a 35 (transmission unit), a segment reproduction unit 36 (reproduction unit), a disconnection time measurement unit 37, a group departure processing unit 38 (second distribution instruction unit), and an address holding unit 39.

When the own terminal takes the initiative, the group building unit 31 transmits a request for building a receiving terminal group that receives the stream-sharing video distribution to the distribution server 10. Further, the group building unit 31 receives the group ID from the distribution server 10 in response to this request, and notifies the group ID to the other receiving terminals 30 that build the receiving terminal group.
On the other hand, the group building unit 31 of the receiving terminal 30 that has received the notification of the group ID from another terminal transmits the notified group ID to the distribution server 10. As a result, the distribution server 10 receives the same group ID from the receiving terminals 30 belonging to the same receiving terminal group, and constructs the receiving terminal group.

The inter-terminal communication monitoring unit 32 monitors the connection quality of inter-terminal communication within the receiving terminal group, and detects the non-delivery of the moving image segment transmitted to the other receiving terminal 30. Specifically, the inter-terminal communication monitoring unit 32 determines that the non-delivery is made when there is no arrival notification of the moving image segment from the receiving terminal 30 on the receiving side of the inter-terminal communication.

The distribution instruction unit 33 receives identification information of the own terminal and other receiving terminals 30 to which the video segment is transmitted, and non-delivery, in response to the detection of non-delivery of the video segment by the inter-terminal communication monitoring unit 32. Notify the retransmission server 20 of the distribution instruction specifying the number of the moving image segment that has been reached.

Here, the delivery instruction to notify the retransmission server 20 when the receiving terminal 30 detects the non-delivery of the moving image segment includes the following three notification contents.
(1) Information of the own terminal that detected the non-delivery of the video segment (for example, IP address)
(2) Information (for example, IP address) of the receiving terminal 30 on the other side where the video segment is not delivered.
(3) Number of the video segment that was not delivered

The segment receiving unit 34 receives the remaining moving image segments by inter-terminal communication from some moving image segments distributed from the distribution server 10 and other receiving terminals 30 in the receiving terminal group.
Further, the segment receiving unit 34 receives the moving image segment transmitted from the retransmission server 20 toward the own terminal in response to the distribution instruction.

The segment transmission unit 35 transmits a part of the moving image segment received from the distribution server 10 to another receiving terminal 30 included in the receiving terminal group by inter-terminal communication.

The segment reproduction unit 36 sequentially reproduces a series of moving image segments received from any of the routes by the segment receiving unit 34 according to the numbers of these moving image segments.
In this way, the receiving terminal 30 receives a part of the segment distributed from the distribution server 10 among the series of video segments constituting the moving image, and shares the series of segments within the receiving terminal group by inter-terminal communication. To play.

The disconnection time measuring unit 37 determines the source of the moving image segment received by the segment receiving unit 34, and measures the time when there is no reception from another receiving terminal 30, that is, the inter-terminal communication is disconnected.

In response to the withdrawal request from the receiving terminal group, the group leaving processing unit 38 sets the identification information of the own terminal and the other receiving terminals 30 to which the own terminal is transmitting the video segment, and the own terminal plans to transmit. Notify the resend server 20 of the distribution instruction including the number of the moving image segment of.
The withdrawal request from the receiving terminal group may be an operation input of the user of the receiving terminal 30, or may be generated when the moving image segment is not received from another receiving terminal 30 for a predetermined time.

Here, the distribution instruction notified to the retransmission server 20 when the receiving terminal 30 leaves the receiving terminal group includes the following three notification contents.
(1) Information of own terminal (for example, IP address)
(2) Information (for example, IP address) of the receiving terminal 30 on the other side, that is, another receiving terminal 30 in the receiving terminal group, in which the video segment is not delivered when the own terminal leaves the receiving terminal group.
(3) Video segment number that cannot be transmitted when the own terminal leaves the receiving terminal group

The address holding unit 39 stores the information of the receiving terminal 30 and the distribution server 10 included in the receiving terminal group, as well as the information (for example, IP address) of the retransmission server 20 notified from the distribution server 10.

FIG. 8 is a diagram showing an operation flow of the distribution system 1 when the inter-terminal communication according to the present embodiment is disconnected.
Here, the operation when the communication between the terminals from the receiving terminal 30A to the receiving terminal 30B is disconnected is illustrated.

In step S11, the receiving terminal 30A on the transmitting side of the inter-terminal communication transmits the moving image segment received from the distribution server 10 by the own terminal to the receiving terminal 30B on the transmitting side.

In step S12, the receiving terminal 30A (inter-terminal communication monitoring unit 32) on the transmitting side monitors the connection quality of the inter-terminal communication, and detects non-delivery when there is no arrival notification of the video segment from the receiving terminal 30B on the receiving side. To do.

In step S13, the receiving terminal 30A that has detected the non-delivery of the moving image segment transmits the distribution instruction of the undelivered moving image segment to the retransmission server 20. The address information of the retransmission server 20 may be notified from the distribution server 10, and may be notified in advance at the start of distribution and stored in the address holding unit 39.

In step S14, the retransmission server 20 transmits the moving image segment, which has not been delivered in the inter-terminal communication, to the receiving terminal 30B on the receiving side in the inter-terminal communication in response to the distribution instruction.

In step S15, the receiving terminal 30B on the receiving side reproduces the moving image segment received from the retransmission server 20.

FIG. 9 is a diagram illustrating a flow of distribution of a moving image segment when the inter-terminal communication according to the present embodiment is disconnected.
In this example, the case where the receiving terminal 30A detects the non-delivery of the moving image segment transmitted to the receiving terminal 30B is shown.

The receiving terminal 30A transmits the moving image segments (numbers: 1, 4, 7, 10, 13, ...) Received from the distribution server 10 to the receiving terminals 30B and 30C. Of these, when the video segment of number 7 transmitted to the receiving terminal 30B is not delivered, the receiving terminal 30A notifies the retransmission server 20 of a distribution instruction to transmit the video segment of number 7 to the receiving terminal 30B. To do.
As a result, the moving image segment undelivered in the inter-terminal communication is provided from the retransmission server 20, and the receiving terminal 30B can acquire a series of moving image segments.

FIG. 10 is a diagram illustrating a flow of generation of a withdrawal request from the receiving terminal group due to disconnection of communication between terminals according to the present embodiment.

In step S21, the receiving terminal 30 on the receiving side in the inter-terminal communication newly receives the moving image segment. This video segment is either received from the distribution server 10, received from another receiving terminal 30 in the receiving terminal group, or received from the retransmission server 20 based on the distribution instruction by the receiving terminal 30 on the transmitting side. Is.

In step S22, the receiving terminal 30 on the receiving side determines whether or not the received moving image segment is acquired from the retransmission server 20. If this determination is YES, the process proceeds to step S23, and if the determination is NO, the process proceeds to step S26.

In step S23, since the receiving terminal 30 on the receiving side has acquired the video segment from the retransmission server 20 instead of from the other receiving terminals 30 in the receiving terminal group, it is determined that the communication between the terminals is disconnected. The cumulative cutting time t is measured.

In step S24, the receiving terminal 30 on the receiving side determines whether or not the measured disconnection time t exceeds a predetermined threshold value T. If this determination is YES, the process proceeds to step S25, and if the determination is NO, the process returns to step S21.

In step S25, the receiving terminal 30 on the receiving side determines that it is difficult to recover because the inter-terminal communication is continuously disconnected, and separates the own terminal from the receiving terminal group of the inter-terminal communication. At this time, the receiving terminal 30 transmits a distribution instruction to the retransmission server 20 and then reconfigures a new receiving terminal group. As a result, the receiving terminal 30 that has left the receiving terminal group sequentially receives the subsequent moving image segments from the distribution server 10.

In step S26, the receiving terminal 30 on the receiving side determines that the communication between the terminals has returned to normal, and resets the timer for measuring the cumulative disconnection time. After that, the process returns to step S21.
The receiving terminal 30 may reset the timer by determining that the inter-terminal communication has returned to normal by receiving a predetermined number of times or frequency instead of one reception by the inter-terminal communication.

FIG. 11 is a diagram illustrating a flow of distribution of a moving image segment when the receiving terminal 30 according to the present embodiment leaves the receiving terminal group.
In this example, when the receiving terminal 30A completes transmitting the video segment of the numbers 1 and 4 to the receiving terminals 30B and 30C by the terminal-to-terminal communication, in response to an explicit withdrawal request from the user, or the terminal-to-terminal communication is performed. It shows the case where the receiving terminal group is left in response to the disconnection.

At this time, the video segments of numbers 7, 10, 13, ... That should have been transferred from the receiving terminals 30A by inter-terminal communication are transferred from the receiving terminals 30A so that the playback of the moving images is not interrupted by the receiving terminals 30B and 30C. In response to the delivery instruction by 30A, the retransmission server 20 delivers the delivery to the receiving terminals 30B and 30C at high speed.

The number of video segments distributed from the retransmission server 20 to the receiving terminals 30B and 30C is the time required for the distribution server 10 to reconfigure the receiving terminal group and redetermine the numbers of the video segments to be distributed to the receiving terminals 30B and 30C. Is determined in consideration of. In this example, there are three moving image segments, numbers 7, 10 and 13.

FIG. 12 is a diagram illustrating a flow of distribution of a moving image segment before and after the receiving terminal group according to the present embodiment is reconstructed.
In this example, when the receiving terminal 30A leaves as shown in FIG. 11, the receiving terminal group including the two receiving terminals 30B and 30C is reconfigured.

After the receiving terminal group is reconfigured, the distribution server 10 distributes the video segment of the number 14 that has already been distributed to the receiving terminal 30B into a sequence of video segments of numbers 16, 18, ... Be changed. Further, from the distribution server 10 to the receiving terminal 30C, the distribution is changed to the moving image segments of a sequence of numbers 17, 19, ... After the number 15.

The video segments of numbers 7, 10 and 13 that are not included in the video segment delivered after this reconstruction and are scheduled to be acquired from the receiving terminal 30A are retransmitted in response to the delivery instruction notified from the receiving terminal 30A. It is transmitted from the server 20 to the receiving terminals 30B and 30C.

According to the present embodiment, in the distribution system 1, each receiving terminal 30 constitutes a moving image by sharing a part of the segments distributed from the distribution server 10 among the receiving terminals 30 in the group by inter-terminal communication. Play a series of segments.
At this time, when wireless inter-terminal communication is utilized, the throughput may fluctuate or the communication may be disconnected due to the influence of the radio wave environment around the receiving terminal 30 as compared with the wired communication. In the present embodiment, when the throughput of communication between terminals is significantly reduced or the communication is cut off, the video segment cannot be transferred and shared between the receiving terminals 30, and the video segment is not delivered. Is transmitted from the retransmission server 20 provided separately from the normal distribution server 10 to the receiving terminal 30 on the receiving side.

Therefore, the distribution system 1 can stably continue the video reproduction even when the communication environment deteriorates in the video distribution using the inter-terminal communication. In particular, by installing the retransmission server 20 in the mobile carrier network and transmitting the video segment to the receiving terminal 30 without going through the Internet, the distribution system 1 stably and quickly re-distributes the undelivered video segment. The moving image can be seamlessly continued to be played back on the receiving terminal 30.

Further, when the distribution system 1 cannot share the video segment by the communication between the terminals due to the movement of any of the receiving terminals 30 constituting the receiving terminal group or the deterioration of the communication condition between the terminals. The corresponding receiving terminal 30 is separated from the receiving terminal group. At this time, the distribution system 1 reconfigures the receiving terminal group and distributes the video segment that cannot be shared from the retransmission server 20 to the receiving terminal 30.
As a result, the distribution system 1 can continue seamless video reproduction without impairing the perceived quality even when the receiving terminal group is reconfigured due to the withdrawal of the receiving terminal 30 from the receiving terminal group.

Further, the distribution system 1 plans to separate the receiving terminal 30 from the receiving terminal group and share it by the terminal-to-terminal communication when the moving image segment is received from the retransmission server 20 and the reception by the terminal-to-terminal communication is not performed for a predetermined time. The moving image segment is distributed from the retransmission server 20.
As a result, the distribution system 1 can suppress an increase in the load on the retransmission server 20 and the network in response to the deterioration of the communication environment, and can continue stable moving image reproduction as a whole system.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Further, the effects described in the present embodiment merely list the most preferable effects arising from the present invention, and the effects according to the present invention are not limited to those described in the present embodiment.

In the above-described embodiment, the retransmission server 20 is installed in the mobile carrier network, but the present invention is not limited to this, and the retransmission server 20 may be installed in any place from the mobile carrier network to the receiving terminal 30. For example, it may be installed in the mobile base station or in the local network to which the receiving terminal group belongs, and the definition of the network switch installation location may be changed according to the installation location of the retransmission server 20.

In the present embodiment, the configuration and operation of the distribution system 1 have been mainly described, but the present invention is not limited to this, and each component may be provided and configured as a method or a program for distributing video data. ..

Further, a program for realizing the function of the distribution system 1 may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer system and executed. ..

The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system.

Furthermore, a "computer-readable recording medium" is a communication line that transmits a program via a network such as the Internet or a communication line such as a telephone line, and dynamically holds the program for a short period of time. It may also include a program that holds a program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or a client in that case. Further, the above-mentioned program may be a program for realizing a part of the above-mentioned functions, and may be a program for realizing the above-mentioned functions in combination with a program already recorded in the computer system. ..

1 Distribution system 10 Distribution server 11 Group management unit 12 Segment determination unit 13 Segment storage unit 14 Segment transmission unit 20 Retransmission server 21 Distribution instruction reception unit (instruction reception unit)
22 Segment determination unit 23 Segment storage unit (accumulation unit)
24 segment transmitter (transmitter)
30 Receiving terminal 31 Group construction unit 32 Inter-terminal communication monitoring unit (detection unit)
33 Delivery instruction unit (first distribution instruction unit)
34 segment receiver (receiver)
35 segment transmitter (transmitter)
36 segment playback section (playback section)
37 Disconnection time measurement unit 38 Group departure processing unit (second delivery instruction unit)
39 Address holder

Claims (5)

A receiving terminal that receives a part of the segments distributed from the distribution server among a series of segments constituting a moving image, and shares and plays the series of segments within a group by inter-terminal communication.
A receiver that receives the part of the segment from the distribution server and the remaining segments from other receiving terminals in the group.
A transmitter that transmits some of the segments to the other receiving terminal,
A playback unit that sequentially reproduces the received series of segments according to the segment numbers, and
A detector that detects the non-delivery of the segment transmitted to the other receiving terminal, and
In response to the detection of non-delivery of the segment, the first method of notifying the retransmission server of the identification information of each of the other receiving terminals to which the segment is transmitted and the distribution instruction specifying the number of the segment. With a delivery instruction unit,
The receiving unit is a receiving terminal that further receives a segment transmitted from the retransmission server to the own terminal in response to the distribution instruction. In response to a request to leave the group, distribution including identification information of the own terminal and the other receiving terminal to which the partial segment is transmitted, and the number of the partial segment to be transmitted by the own terminal. The receiving terminal according to claim 1, further comprising a second distribution instruction unit that notifies the instruction to the retransmission server. The receiving terminal according to claim 2, wherein the withdrawal request occurs when the remaining segment is not received from the other receiving terminal for a predetermined time. By sharing some segments distributed from the distribution server within the group by inter-terminal communication, it is connected to multiple receiving terminals that play a series of segments that make up the video.
An instruction to receive the identification information of the other receiving terminal and the distribution instruction specifying the number of the segment in response to the detection of the non-delivery of the segment transmitted to the other receiving terminal in the group by the receiving terminal. With the receiver
A storage unit that stores the series of segments common to the distribution server,
A retransmission server including a transmission unit that transmits a segment of a number specified by the distribution instruction to the other receiving terminal in response to the distribution instruction. A receiving terminal that receives a part of the segments distributed from the distribution server among the series of segments constituting the moving image and shares and plays the series of segments within the group by inter-terminal communication.
A receiving step of receiving the part of the segment from the distribution server and the remaining segments from other receiving terminals in the group.
A transmission step of transmitting the part of the segment to the other receiving terminal, and
A reproduction step of sequentially reproducing the received series of segments according to the segment numbers, and
A detection step for detecting non-delivery of a segment transmitted to the other receiving terminal, and
In response to the detection of non-delivery of the segment, the first method of notifying the retransmission server of the identification information of each of the other receiving terminals to which the segment is transmitted and the distribution instruction specifying the number of the segment. To execute the delivery instruction step and
A receiving program for receiving a segment transmitted from the retransmission server to the own terminal in response to the delivery instruction in the receiving step.

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