WO2022219876A1

WO2022219876A1 - Display device, display system, and display method

Info

Publication number: WO2022219876A1
Application number: PCT/JP2022/003145
Authority: WO
Inventors: 章裕脇田; 和也我妻
Original assignee: 株式会社日立製作所
Priority date: 2021-04-14
Filing date: 2022-01-27
Publication date: 2022-10-20
Also published as: JP2022163607A

Abstract

A content group is displayed while a plurality of display devices are being synchronized without a specific device serving as a master. A display device (3a) comprises: a transmission unit (33a) that transmits a synchronization signal to another device; a reception unit (34a) that receives the synchronization signal from the other device; a content group acquisition unit (311) that repeatedly acquires a content group for the device from a playlist; a video display unit (314) that repeatedly reproduces video based on the content group; a synchronization determination unit (312) that, when the reception unit (34a) receives the synchronization signal while the video display unit (314) is displaying the current content group, causes the reproduction of the current content group to be stopped and causes the next content group to be reproduced; and a synchronization signal transmission control unit (313) that, when the video display unit (314) finishes displaying the current content group, causes the synchronization signal to be transmitted from the transmission unit (33a) to the other device.

Description

Display device, display system, and display method

The present invention relates to a display device, a display system, and a display method for displaying information transmitted from the outside, for example.

In recent years, display devices that display externally transmitted information (hereinafter referred to as content) have become widespread in various fields. When displaying content on a plurality of display devices installed in one place, each display device displays content using its own reference clock. The accuracy of the reference clock that each display device has varies depending on the environment (for example, temperature and individual differences in hardware). Therefore, in a plurality of display devices, differences in content display time are accumulated.

In order to solve the above problem, a conventional system for displaying content is arranged such that a plurality of other display devices (hereinafter referred to as slave display devices) display content in accordance with an instruction from one master display device. Display systems are common.

However, with the method of displaying according to the master device, if the master device goes down due to a failure, etc., the display cannot be continued, and the visibility of the content is significantly reduced.

Patent Document 1 solves this problem. The abstract of Patent Document 1 states, "The broadcast receiving unit 6 receives ID information transmitted from each of a plurality of in-vehicle video reproducing apparatuses including its own apparatus, and transmits local time corresponding to the received time. It is acquired from the time management unit 10 and added to the ID information.The synchronization control unit 8 calculates the time adjustment amount based on the value of the local time added to each of the plurality of pieces of ID information accumulated in the reception data management unit 7. is calculated.”

JP 2015-170369 A

As described above, the accuracy of the reference clock that each display device has varies depending on the environment. Therefore, a difference in content display time accumulates in a plurality of display devices.
Consider a display system that repeatedly displays a plurality of contents (hereinafter referred to as a "content group") on a plurality of display devices. The number of repetitions of displaying the content group by this display system is referred to as the “number of display cycles”. When the content group displayed by the display system differs depending on the number of display cycles, some display devices may be displayed on some display devices for some reason (e.g., unexpected restart of the display device, power ON/OFF operation of the display device, etc.). When there is a discrepancy in the number of display cycles, the content group to be displayed differs between the display device in which the discrepancy in the number of display cycles has occurred and the display device in which the discrepancy in the number of display cycles has not occurred.

Therefore, an object of the present invention is to display a group of contents while synchronizing between a plurality of display devices without having a specific master device.

In order to solve the above-described problems, the display device of the present invention includes a transmission unit that transmits a synchronization signal to another device, a reception unit that receives the synchronization signal from the other device, and a content group for the own device from a playlist. a content group acquisition unit that repeatedly acquires a content group; a video display unit that repeatedly reproduces video based on the content group; a synchronizing determination unit for rounding up the reproduction of the group and reproducing the next content group; and synchronizing signal transmission for transmitting a synchronizing signal from the transmitting unit to the other device when the video display unit finishes displaying the current content group. and a control unit.

The display system of the present invention includes a central device installed in one train set, terminal devices installed in each vehicle constituting the train and capable of communicating with the central device, and each vehicle in the train. a plurality of display devices that are installed, connected to the terminal device via a network and connected to each other, and repeat reproduction of the content group while synchronizing with the timing at which the reproduction of the content group is completed first. It is characterized by

A display method according to the present invention includes the steps of: a content group acquisition unit acquiring a content group for its own device from a playlist; a video display unit repeatedly playing video based on the content group; When the synchronization determination unit receives a synchronization signal from another device during reproduction of the above, the reproduction of the current content group is stopped; and when the video display unit finishes displaying the current content group, the transmission unit and causing the other device to transmit a synchronization signal including the number of display cycles.
Other means are described in the detailed description.

According to the present invention, it is possible to display a group of contents while synchronizing between a plurality of display devices without having a specific master device.

1 is an overall configuration diagram of a system including a display device according to an embodiment; FIG. 1 is a block diagram of a display device; FIG. FIG. 2 is a diagram showing the configuration of a basic playlist; FIG. FIG. 3 is a diagram showing a group of contents of a basic playlist; FIG. 10 is a sequence diagram showing operations of synchronization signal transmission, update of the number of display rotations, and immediate reproduction among a plurality of display devices; FIG. 10 is a diagram showing the structure of a playlist of content groups to which the number of display rounds has been added; FIG. 10 is a diagram showing a content group for each number of display cycles; FIG. 10 is a sequence diagram showing an operation of restoring a display state after a display device having a group of contents based on the number of display cycles resets the number of display cycles due to a reboot or the like and a large deviation occurs. FIG. 10 is a diagram showing a playlist with a device ID added as a condition; FIG. 10 is a diagram showing a group of contents in which a device ID is added as a condition; FIG. 10 is a diagram showing the configuration of a playlist to which a plurality of conditions including the number of display laps, device ID, car number, direction of travel, and train position are added as conditions. It is a figure which shows the structure of train information. It is a figure which shows the structure of a train information storage part. 4 is a flowchart of synchronization processing; 4 is a flowchart of synchronization processing; FIG. 10 is a sequence diagram showing an operation of synchronizing while displaying without impairing the design by sending a content file presence/absence list and skipping within the display device to be synchronized when the content is lost. FIG. 10 is a flowchart of synchronization processing for skipping when content is missing; FIG. FIG. 10 is a flowchart of synchronization processing for skipping when content is missing; FIG.

EMBODIMENT OF THE INVENTION Henceforth, the form for implementing this invention is demonstrated in detail with reference to each figure.
FIG. 1 is an overall configuration diagram of a display system 1 including display devices 3a to 3f in this embodiment.
The display system 1 includes a central device 90 installed in one or more trains,

terminal devices

4a and 4b installed in each

vehicle

2a and 2b constituting the train, and each vehicle 2a and 2b. and one or more display devices 3a to 3f installed in the . Although only the

cars

2a and 2b constituting one train set are illustrated here, the number of cars of the train may be three or more, and is not limited.

The central device 90 controls the display system 1 in an integrated manner. The central unit 90 is connected to the train condition monitoring device 81 and receives the train information 82 from the train condition monitoring device 81 as well as an instruction to start the display of the display system 1 . The central unit 90 is also communicably connected to a terrestrial distribution system 92 that is wirelessly connected to a terrestrial network 93 via an antenna 91, and receives and stores contents and playlists from the terrestrial distribution system 92. FIG. Here, the contents are videos or still images such as advertisements, news, and weather forecasts provided to train passengers. The content received from the terrestrial distribution system 92 may include audio in addition to video. The central device 90 is connected to the terminal device 4a so as to be able to communicate with each other.

The terminal device 4a manages the display devices 3a to 3c installed in the vehicle 2a, and includes a storage unit 41a. The terminal device 4b manages the display devices 3d to 3f installed in the vehicle 2b, and includes a storage section 41b. Then, the terminal device 4a is sequentially connected to the terminal device 4b installed in the next vehicle 2b. Henceforth, it is the same also when the next vehicle or terminal device exists. Thereby, the central device 90 can communicate with the

terminal devices

4a, 4b, .

The display device 3a includes a control unit 31a, a storage unit 32a, a transmission unit 33a, and a reception unit 34a. The control unit 31a is a functional unit embodied by, for example, a CPU (Central Processing Unit) executing a program using a RAM (Random Access Memory). The storage unit 32a is, for example, a nonvolatile mass storage device such as a flash memory. The transmitting unit 33a and the receiving unit 34a are functional units using, for example, a NIC (Network Interface Card), and transmit and receive information to and from the terminal device 4a and

other display devices

3b and 3c via communication paths. be. Similarly, the display devices 3b to 3f include control units 31b to 31f, storage units 32b to 32f, transmission units 33b to 33f, and reception units 34b to 34f, respectively.

When the

terminal devices

4a, 4b, ... receive the playlist and train information from the central device 90, they temporarily store them in the

storage units

41a, 41b. A playlist is an array of meta information indicating a group of contents to be displayed on each of the display devices 3a to 3f. The train information is information such as car number, traveling direction, running position, etc. of the car in which the display devices 3a to 3f (own devices) managed by the

terminal devices

4a, 4b, . . . are installed. The terminal device 4a transmits the playlist and train information to one or more display devices 3a to 3c installed in the vehicle 2a. The terminal device 4b transmits the playlist and train information to one or more display devices 3d to 3f installed in the vehicle 2b. That is, each of the

terminal devices

4a, 4b, . It is configured including an information transmission unit.

FIG. 2 is a block diagram of the display device 3a.
The display device 3a includes a control section 31a, a storage section 32a, a transmission section 33a, and a reception section 34a. This display device 3a displays information transmitted from the outside.

The control unit 31 a includes a content group acquisition unit 311 , a synchronization determination unit 312 , a synchronization signal transmission control unit 313 and a video display unit 314 . The control unit 31a performs overall control of the display device 3a. These functional units are implemented by the CPU (not shown) of the control unit 31a executing a display program stored in a storage unit (not shown).

The content group acquisition unit 311 acquires its own content group from the playlist.
The synchronization determination unit 312 compares the number of display cycles of the synchronization signal received from either of the

other display devices

3b and 3c with the number of display cycles of the own device (display device 3a). Then, when the number of display cycles of the device itself is equal to or greater than the number of display cycles of the synchronization signal received from the other device, the synchronization determination unit 312 sets the number of display cycles of the received synchronization signal as the number of display cycles of the device itself. When the synchronization determination unit 312 adds 1 to the number of display cycles of its own device and updates it, the display of the current content group is rounded up and the next content group is displayed.

Synchronization signal transmission control unit 313 causes synchronization signal transmission unit 332 to transmit synchronization signals to

other display devices

3b and 3c at the same time when all content groups have been displayed, and adds 1 to the number of display cycles of the own device. and control the update.
The image display unit 314 is, for example, a liquid crystal panel or an organic EL (Electro Luminescence) panel, and reproduces each content file of the content group to display an image.

The transmission unit 33 a includes a playlist transmission unit 331 and a synchronization signal transmission unit 332 .
The playlist transmission unit 331 transmits the playlist to the

other display devices

3b and 3c.
The synchronization signal transmission section 332 transmits synchronization signals to the

other display devices

3b and 3c.

The storage unit 32 a includes a playlist storage unit 321 , a display lap number storage unit 322 , and a train information storage unit 323 .
The playlist storage unit 321 stores playlists. The number-of-display-wraps storage unit 322 stores the number of times of display of the current content group. The train information storage unit 323 stores information on trains on which the display system 1 is installed.

The receiver 34 a includes a playlist receiver 341 , a train information receiver 343 , and a synchronization signal receiver 342 .
The playlist receiving unit 341 receives playlists from

other display devices

3b and 3c and

terminal devices

4a and 4b. The train information receiving unit 343 receives the train information 82 from the terminal device 4a. The synchronizing signal receiver 342 receives synchronizing signals from the

other display devices

3b and 3c.

FIG. 3A is a diagram showing the configuration of a basic playlist 1001. As shown in FIG.
A content ID column 1098 and a content file name column 1099 are defined in the basic playlist 1001 . The content ID column 1098 stores content identifiers. The content file name column 1099 stores the file name of the content.

If there are no conditions, the content group acquisition unit 311 acquires all files in the playlist 1001 as the content group 2001.

FIG. 3B is a diagram showing the content group 2001 of the basic playlist 1001. As shown in FIG.
A content group 2001 is content indicated in the content file name column 1099 of the playlist 1001 . The display device 3a repeats the display of this content group 2001 from the beginning to the end.

FIG. 4 is a sequence diagram showing operations of transmission of synchronization signals, updating of the number of display cycles, and immediate reproduction among a plurality of display devices. FIG. 4 shows the timing of synchronization in this embodiment.
When the display devices 3a-3c are activated, the number of display cycles is set to 1 (steps S10a-S10c). Then, the display devices 3a-3c start reproducing the content group 2001 (steps S11a-S11c).

Here, the display device 3b finishes displaying the content group 2001 earliest and transmits a synchronization signal including the number of display cycles to the

display devices

3a and 3c (step S12). Next, the display device 3b adds 1 to the number of display cycles, acquires the next content group 2001, and displays the acquired content group (step S13b).

The

display devices

3a and 3c compare the number of display cycles of the received synchronization signal with the number of display cycles of their own devices. When the number of display cycles of the synchronization signal is equal to or greater than the number of display cycles of the own device, the

display devices

3a and 3c update the number of display cycles of the own device to the number of display cycles of the synchronization signal, and then add 1 to the number of display cycles.

The

display devices

3a and 3c stop displaying the current content group 2001, acquire the next content group 2001, and start displaying the acquired content group 2001 (steps S13a and S13c).

It should be noted that the playlist 1001 shown in FIG. 3A and the content group 2001 shown in FIG. 3B are for repeatedly reproducing the same content regardless of the number of display cycles. Therefore, in such a case, the display device that has completed the reproduction of the content group first may simply transmit the synchronization signal to the other display devices without including the number of display rounds in the synchronization signal.

FIG. 5A is a diagram showing the structure of a content group playlist 1002 to which a display cycle count column has been added.
In the playlist 1002, in addition to a content ID column 1098 and a content file name column 1099, a display cycle number column 1097 is defined. The content ID column 1098 stores content identifiers. The content file name column 1099 stores the file name of the content. The number of display rounds column 1097 describes conditions for the number of display rounds for reproducing this content.

This playlist 1002 is for the case where the number of display cycles is used as a condition for creating a content group. In this case, the content group acquisition unit 311 acquires content groups 2021 to 2023 by extracting content corresponding to the number of display cycles.

FIG. 5B is a diagram showing the correspondence between the number of display cycles and content groups.
When the number of display cycles is 1, the content group acquisition unit 311 acquires the content group 2021 . This content group 2021 contains b.mpg second.
When the number of display cycles is 2, the content group acquisition unit 311 acquires the content group 2022 . This content group 2022 includes c.mpg second.
When the number of display cycles is 3, the content group acquisition unit 311 acquires the content group 2023 . This content group 2023 includes d.mpg second.

FIG. 6 shows that the display device 3c, which has a group of contents based on the number of display rounds, resets the number of display rounds due to a reboot or the like, and after a large discrepancy with the

other display devices

3a and 3b occurs, the display state is restored. FIG. 10 is a sequence diagram showing an operation to perform;

The number of display cycles of the display devices 3a-3c is set to 2 (steps S20a-S20c). Then, the display devices 3a-3c start reproducing the next content group (steps S21a-S21c).

Then, an unexpected restart occurs while the display device 3c is reproducing the content group (step S22). The display device 3c sets the number of display cycles to 1 (step S23), and reproduces the content group (step S24).

Next, the display device 3b finishes the reproduction of the second display cycle, transmits a synchronization signal to the

other display devices

3a and 3c (step S25), and reproduces the next content group (step S26b).

When the display device 3a sets the number of display cycles to 3 according to the synchronization signal received from the display device 3b, it interrupts the reproduction of the current content group and reproduces the next content group (step S26a).

The display device 3c sets the number of display cycles to 3 according to the synchronization signal received from the display device 3b. Display is performed (step S26c). This allows the display device 3c to synchronize playback again.

Also, assume that the display device 3c has finished displaying the content group first and has transmitted a synchronization signal including information on the number of display cycles of 1 to the

display devices

3a and 3b. The

display devices

3a and 3b do not interrupt the reproduction of the content group because the number of display cycles of their own devices is smaller than the number of display cycles of the received synchronization signal.

FIG. 7A is a diagram showing a playlist 1003 with a device ID added as a condition.
A content ID column 1098 , a content file name column 1099 , and a device ID column 1096 are defined in the playlist 1003 . The content ID column 1098 stores content identifiers. The content file name column 1099 stores the file name of the content. The device ID column 1096 stores the identifier of the display device that reproduces the content. A.mpg is played on all display devices. On the other hand, B.mpg is played on the display device with the device ID of 1, C.mpg is played on the display device with the device ID of 2, and D.mpg is played on the display device with the device ID of 3. . By doing so, for example, a display device with a device ID of 1, a display device with a device ID of 2, and a display device with a device ID of 3 are installed side by side. D.mpg are the left, center, and right sides of the panorama video, respectively, the entire panorama video can be reproduced on these three display devices.

FIG. 7B is a diagram showing content groups 2041a to 2041c for each number of display cycles.
A device ID=1 is assigned to the display device 3a. A device ID=2 is assigned to the display device 3b. A device ID of 3 is assigned to the display device 3c.
In the case where the playlist 1003 has a device ID as a condition, the content group acquisition unit 311 of the display device 3a acquires an extracted video corresponding to the device ID as a content group 2041a. Similarly, the content group acquisition unit 311 of the display device 3b acquires an extracted video corresponding to the device ID as a content group 2041b. The content group acquisition unit 311 of the display device 3c acquires an extracted video corresponding to the device ID as a content group 2041c.
Operationally, it is desired that the display devices 3a to 3c have the same playback time for the content groups 2041a to 2041c.

FIG. 8A is a diagram showing the configuration of a playlist 1004 to which a plurality of conditions including the number of displayed laps, the device ID, the car number, the traveling direction, and the train position are added.
The playlist 1004 includes a content ID column 1098, a content file name column 1099, a display lap count column 1097, a device ID column 1096, a car number column 1084, a travel direction column 1085, and a train position column 1086. is stored including A playlist 1004 is a playlist defined by information including train information 82 received from the train condition monitoring device 81, such as a car number, traveling direction, and train position, in the case of having a plurality of conditions.

The content ID column 1098 stores content identifiers. The content file name column 1099 stores the file name of the content. The display cycle count stores the display cycle count of the content. The device ID column 1096 stores the identifier of the device that reproduces the content.

Furthermore, in the car number column 1084, car number information on which this display device is installed is stored. The traveling direction column 1085 stores the traveling direction of the train. The train position column 1086 stores the position information of this train.

FIG. 8B is a diagram showing the structure of train information 82. As shown in FIG.
The train information 82 includes car number information, traveling direction information, and train position information. This train information 82 is transmitted from the

terminal devices

4a and 4b shown in FIG. 1 to each of the display devices 3a to 3f. Of the train information 82, the information on the traveling direction and train position is transmitted from the train condition monitoring device 81 to the

terminal devices

4a and 4b via the central device 90. FIG. The information of the car in the train information 82 is set by the

terminal devices

4a and 4b.

FIG. 8C is a diagram showing information in the train information storage unit 323. As shown in FIG.
The train information storage unit 323 stores the contents of the above-described train information 82 to which a device ID is added.
The content group acquisition unit 311 of each display device can acquire an appropriate content group according to the current situation from the train information 82 stored in the display cycle number storage unit 322 and the train information storage unit 323. be. Specifically, for example, depending on the train position, the content group acquisition unit 311 can acquire the advertising content of the store corresponding to the train position. Thus, the display system 1 can display appropriate advertising content to train passengers.

9A and 9B are flowcharts of synchronization processing.
The display devices 3a to 3f start displaying content when some start condition is satisfied. In practical use, it is desired that each of the display devices 3a to 3f satisfy the start condition at the same timing. The flowchart of the subsequent synchronization processing will be described using the display device 3a as an example.
In step S30, the content group acquisition unit 311 of the control unit 31a acquires the content group of the number of display rounds from the train information and the playlist.

In step S31, the synchronization determination unit 312 of the control unit 31a determines whether all the contents of the content group have been displayed. If display of all the contents has not been completed (No), the control unit 31a proceeds to step S32. Then, the video display unit 314 displays the next content in the content group.

In step S31, when all the contents have been displayed, the synchronizing signal transmission control unit 313 transmits the synchronizing signal to which the number of display cycles of the own device is added to all other devices (step S33). Then, the synchronization signal transmission control unit 313 adds 1 to the number of display cycles (step S34), and returns to the process of step S30.

On the other hand, as shown in FIG. 9B, when the synchronization signal transmitted by the other device is received in step S33 (step S40), the synchronization determination unit 312 determines that the number of display cycles of the received synchronization signal is greater than or equal to the number of display cycles of the own device. (step S41). When the number of display cycles of the synchronization notification is less than the number of display cycles of the own device (No), the display device 3a continues the operation before receiving the synchronization signal (step S42).

If the number of display cycles of the synchronization notification is greater than or equal to the number of display cycles of the device itself (Yes), the synchronization determination unit 312 determines that the number of display cycles of the synchronization signal of the other device received in step S40 is equal to the number of display cycles of the device itself. It is determined whether they match (step S43). If the number of display cycles of the synchronization signal received from the other device does not match the number of display cycles of the device itself, the synchronization determination unit 312 updates the number of display cycles of the device with the number of display cycles of the received synchronization signal (step S44). After that, the synchronization determination unit 312 adds 1 to the number of display cycles of its own device (step S45), and acquires the content group corresponding to the number of display cycles from the play list (step S46). When the synchronization determination unit 312 terminates the display of the current content group (step S47), the process returns to step S31.

FIG. 10 is a sequence diagram showing an operation of synchronizing while displaying by sending content file presence/absence list information and skipping within the display device to be synchronized when content is lost.
This diagram illustrates synchronization processing when content B on the display device 3a cannot be displayed due to file loss when the content group 2001 is displayed on the display devices 3a to 3c. The display devices 3a to 3c acquire the content group 2001 of the number of rounds, check whether all the files described in the content group 2001 are present in the display devices 3a to 3c, and create the content file presence/absence list information. At this time, since the display device 3a lacks the content B and cannot display it, it adds information indicating that there is no content B to the content file presence/absence list information and that there are other contents, and notifies the

display devices

3b and 3c. . Since the

display devices

3b and 3c do not have any missing content, they add information indicating that there are all content files to the content file presence/absence list information, and notify the

display devices

3a and 3c and the

display devices

3b and 3c. Since the display device 3a does not have the content B, the content C is displayed after the content A is displayed. In addition, the

display devices

3b and 3c display the content C without displaying the content B after displaying the content A based on the content file presence/absence list information. By this process, the display devices 3a to 3c skip the content B in common. In addition, by acquiring the next content group and creating a content file presence/absence list at the timing when the display of the current content group ends, even when the content group is switched according to the number of display cycles, any display device can be used. Synchronization between display devices is achieved by skipping the display of missing content.

FIGS. 11A and 11B are flowcharts of synchronization processing for skipping when content is lost.
A flowchart of synchronization processing when skip processing is performed when content is missing will be described with the display device 3a as the operating body.

The display device 3a starts displaying content when some start condition is satisfied. In actual operation, it is desirable that each display device satisfies the start condition at the same timing.
After that, in step S70, the content group acquisition unit 311 of the control unit 31a acquires the content group corresponding to the number of display rounds from the play list. Then, the content group acquisition unit 311 confirms whether or not the content file described in the content group is held, and creates content file presence/absence list information (step S71).

After that, the content group acquisition unit 311 notifies the content file presence/absence list information to other devices to be synchronized (step S72). After that, the content group acquisition unit 311 receives the content file presence/absence list information from the other device to be synchronized (step S72).

The control unit 31a determines whether or not the display of all content in the content group has been completed (step S74). If the display of all the contents has not been completed (No), the control unit 31a proceeds to step S75, and checks whether all the other devices to be synchronized have the file of the next content from the content file presence/absence list information. determine whether or not If the display of all the contents has been completed (Yes), the control unit 31a proceeds to step S82 in FIG. 11B.

If all other devices have files of the next content (Yes), the control unit 31a proceeds to step S77. If any of the other devices does not have the file of the next content (No), the process proceeds to step S76 to notify the subsequent content held by all the other display devices (other devices) to be synchronized. and proceed to step S77. That is, the video display unit 314 does not reproduce the content notified of the loss from the other device, but reproduces the content following this content.

In step S77, the control unit 31a determines whether the next content is the last content in the current content group. If the next content is the last content (Yes), the controller 31a proceeds to parallel processing in FIG. 11B, and if the next content is not the last content (No), the controller 31a proceeds to step S78.

In step S78, the control unit 31a causes the video display unit 314 to display the next content in the content group, and then returns to the processing of step S74.

The parallel processing in FIG. 11B includes a process in which the video display unit 314 displays content (step S79), and a process in which the content group acquisition unit 311 notifies other devices to be synchronized of content file presence/absence list information (step S80). , a process of receiving content file presence/absence list information from another device to be synchronized (step S81). As a result, the display device 3a can share information about a newly generated loss of a content file with other devices.

In step S82, the synchronizing signal transmission control unit 313 transmits the synchronizing signal to which the number of display cycles of its own device is added to all other devices. Then, the synchronization signal transmission control unit 313 adds 1 to the number of display cycles (step S83), and returns to the process of step S70.

(Effect of this embodiment)
The embodiment described above has the following effects (A) to (F).
(A) This embodiment can display a group of contents while synchronizing between a plurality of display devices without having a specific master device.
(B) In the case where a deviation in the number of display cycles occurs in some display devices, synchronous display can be performed in accordance with the display device in which the deviation in the number of display cycles does not occur, and furthermore, the deviation in the number of display cycles A display device in which is capable of displaying a content group in line with the number of display cycles of a display device in which there is no discrepancy in the number of display cycles.

(C) According to this embodiment, in order to synchronize between multiple display devices, there is no need for a master device that emits timing, and synchronous display is performed in accordance with the display device that completes the display of the content group earliest. can be continued.

(D) When a discrepancy occurs in the number of display cycles on some display devices, it is possible for the display devices where the discrepancy in the number of display cycles does not occur to resume synchronous display at the timing when the display of the content group is completed. In addition, at the same timing, a display device in which a discrepancy in the number of display cycles has occurred can match the number of display cycles with a display device in which the discrepancy in the number of display cycles has not occurred, and a content group according to the number of display cycles can be displayed. can be displayed.

(E) It is possible to reproduce advertisement video according to the number of display cycles only by recording the number of display cycles of one's own device without recording information on multiple other display devices.

(F) Communication for the purpose of synchronization only notifies the number of display laps after the roll ends, so the load imposed on the network is small, and this is a synchronization implementation method that is less likely to be restricted by network performance.

(Modification)
The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. A part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

Some or all of the above configurations, functions, processing units, processing means, etc. may be realized by hardware such as integrated circuits. Each of the above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program for realizing each function. Information such as programs, tables, and files that implement each function can be placed on recording devices such as memory, hard disks, SSDs (Solid State Drives), or recording media such as flash memory cards and DVDs (Digital Versatile Disks). can.

In each embodiment, control lines and information lines indicate those considered necessary for explanation, and not all control lines and information lines are necessarily indicated on the product. In fact, it may be considered that almost all configurations are interconnected.
Modifications of the present invention include, for example, the following (a) to (k).

(a) The train information receiver 343 and train information storage 323 are not necessarily required for synchronization.
(b) In the present embodiment, the central device 90 and the

terminal devices

4a and 4b are described, but they are not necessarily required for synchronization.

(c) In this embodiment, the case where the playlists 1001 to 1004 transmitted from the terrestrial distribution system 92 are communicated via the central device 90 and the

terminal devices

4a and 4b has been described. However, the terrestrial distribution system 92, the central device 90, and the

terminal devices

4a and 4b are not necessarily required. I don't mind.

(d) In this embodiment, the train condition monitoring device 81 is provided, but it is not necessarily required for synchronous display.
(e) In the present embodiment, three display devices 3a to 3f are provided for each of the

vehicles

2a and 2b, but the number is not necessarily three and may be any number.
(f) In the present embodiment, all the display devices in the vehicle have been described as synchronization targets, but it is also possible to divide the synchronization targets in the vehicle by the device ID or the like.

(g) In the present embodiment, synchronization is performed at the timing when all the contents of the content group are finished. It may be possible to synchronize with
(h) In this embodiment, an information display system installed on a train has been described, but the present invention is not limited to this, and may be applied to an information display system installed in a station building, a shopping center, or the like.
(i) The display system of this embodiment acquires a content group based on train information. However, it is not limited to train information, and content groups may be acquired based on environmental information such as weather, atmospheric pressure, humidity, and temperature, and date and time information such as days of the week, holidays, and anniversaries.
(j) In the display system of the present embodiment, when the same content group is continuously reproduced regardless of the number of display cycles, the synchronization signal does not need to include the number of display cycles. In this case, when the reception unit receives the synchronization signal while the video display unit is displaying the current content group, the synchronization determination unit cuts off the reproduction of the current content group and reproduces the next content group. Further, the synchronization signal transmission control section causes the transmission section to transmit the synchronization signal to the other device when the video display section finishes displaying the current content group.
(k) The display system of the present embodiment adds 1 to the number of display cycles and updates it each time a content group is displayed. However, the present invention is not limited to this, and may be updated by adding an arbitrary integer to the number of display cycles.

1

display systems

2a, 2b vehicles 3a to 3f display devices 31a to 31f control unit 311 content group acquisition unit 312 synchronization determination unit 313 synchronization signal transmission control unit 314 video display units 32a to 32f storage unit 321 playlist storage unit 322 number of display cycles Storage unit 323 Train information storage units 33a to 33f Transmission unit 331 Playlist transmission unit 332 Synchronization signal transmission units 34a to 34f Reception unit 341 Playlist reception unit 342 Synchronization signal reception unit 343 Train

information reception units

4a,

4b Terminal devices

41a, 41b Storage unit 90 Central device 81 Train status monitoring device 82 Train information 91 Antenna 93 Terrestrial network 92 Terrestrial distribution system 1001 to 1004 Play list 1098 Content ID column 1099 Content file name column 1097 Display lap number column 1096 Device ID column 1084 Car No. column 1085 Progress Direction column 1086

Train position columns

2001, 2021 to 2023, 2041a to 2041c Group of contents

Claims

a transmission unit that transmits a synchronization signal to another device;
a receiving unit that receives a synchronization signal from the other device;
a content group acquisition unit that repeatedly acquires a content group for its own device from a playlist;
a video display unit that repeatedly reproduces video based on the content group;
a synchronization determination unit that, when the reception unit receives a synchronization signal while the video display unit is displaying the current content group, rounds up the reproduction of the current content group and reproduces the next content group;
a synchronization signal transmission control unit for transmitting a synchronization signal from the transmission unit to the other device when the video display unit finishes displaying the current content group;
A display device comprising:
The synchronization signal transmitted from the own device includes the number of display cycles of the content group of the own device,
The synchronization signal received from the other device includes the number of display cycles of the content group of the other device,
The content group acquisition unit repeatedly acquires a content group according to the number of display cycles of the own device from the playlist,
If the number of display cycles of the other device included in the synchronization signal received by the receiving unit is equal to or greater than the number of display cycles of the own device, the synchronization determination unit rounds up the reproduction of the current content group and displays the content on the other device. Update the number of laps as the display number of laps of your device,
When the video display unit finishes displaying the current content group, the synchronization signal transmission control unit causes the transmission unit to transmit a synchronization signal including the number of display cycles of the own device to the other device, and Update display lap count,
2. The display device according to claim 1, wherein:
The transmission unit
a playlist transmission unit that transmits a playlist to the other device;
a synchronization signal transmission unit that transmits a synchronization signal to the other device;
2. The display device according to claim 1, wherein:
The receiving unit
a playlist receiving unit that receives a playlist from the other device;
a synchronization signal receiving unit that receives a synchronization signal from the other device;
2. The display device according to claim 1, wherein:
Further comprising a storage unit that stores the playlist received by the receiving unit and the number of display cycles of the device itself,
3. The display device according to claim 2, wherein:
The storage unit
a playlist storage unit for storing the playlist received by the receiving unit;
a display lap number storage unit that stores the number of display laps of the content,
6. The display device according to claim 5, wherein:
The receiving unit
Including a train information receiving unit that receives information on the train on which the device is installed from the terminal device,
The storage unit
Including a train information storage unit that stores information on the train,
7. The display device according to claim 6, wherein:
The content group acquisition unit acquires a content group corresponding to the identifier of the own device from the playlist,
2. The display device according to claim 1, wherein:
The content group acquisition unit
Acquire a content group according to the information of the train on which the device is installed from the playlist,
8. The display device according to claim 7, characterized by:
The content group acquisition unit
Acquire a group of contents corresponding to train information including at least one of car number, travel direction, and running position of the vehicle in which the device is installed from the playlist;
10. The display device according to claim 9, characterized in that:
The content group acquisition unit creates a list of the presence or absence of content files from the content group, and if there is a missing content, the transmission unit notifies the other device,
The video display unit does not reproduce the content notified from the other device, but reproduces the content next to the content.
2. The display device according to claim 1, wherein:
A central unit installed in one train set,
a terminal device installed in each vehicle constituting the train and capable of communicating with the central device;
A plurality of devices installed in each vehicle of the train, connected to the terminal device via a network and connected to each other, and repeating reproduction of the content group while synchronizing with the timing at which the reproduction of the content group is completed first. a display device;
A display system comprising:
The terminal device includes a train information transmission unit that transmits, to each of the display devices, train information including at least one of the car number, traveling direction, and running position of the vehicle on which the terminal device is installed,
13. The display system of claim 12, wherein:
a step in which a content group acquisition unit acquires a content group for its own device from a playlist;
a step in which a video display unit repeatedly reproduces a video based on the content group;
stopping the reproduction of the current content group when the synchronization determination unit receives a synchronization signal from another device during reproduction of the current content group;
a step of causing the transmission unit to transmit a synchronization signal including the number of display cycles of the own device to the other device when the video display unit finishes displaying the current content group;
A display method characterized by executing