Digital display method and system.

Abstract

Display method comprising: - generating by a platform (7) for the generation of playlists, playlists intended for digital display devices (2), the playlists having free time slots; - synchronizing the digital display devices with the platform for the generation of playlists; - for each free time slot of each playlist, corresponding to a digital display device, sending a content request by the platform for the generation of playlists, to a programmatic platform (20) for the sale of advertising space, the programmatic platform being adapted to issue a corresponding bid and to send back to the platform for the generation of playlists, information corresponding to content which has won the bid;- to inform the winning bidder, via the playlist generation platform, of the digital display device corresponding to the available time slot. Figure of the summary: Figure 1;

Description

Title of the invention: Digital display method and system. Technical field

[0001] The present description relates to digital display methods and systems. Prior art

[0002] Digital display methods are known for deploying playlists and content to digital display devices. Summary

[0003] The present description aims in particular to improve the efficiency of these methods, in particular to enable the deployment of playlists and content in near real time, including to a large number of digital display devices.

[0004] To this end, the present description proposes a digital display method for controlling the display of digital contents by digital display devices, comprising: - generate by a playlist generation platform, playlists based on display campaigns, each playlist comprising information necessary for one or more of said digital display devices to display a series of digital content during successive time slots, at least some of the playlists having free time slots not allocated to a specific digital content; - repeatedly synchronizing the digital display devices with said playlist generation platform so that each digital display device has in memory the updated playlist generated for it by said playlist generation platform; - for each free time slot of each playlist, corresponding to at least one digital display device, sending a request for content by said playlist generation platform to a programmatic advertising space sales platform, said programmatic advertising space sales platform being adapted to issue an auction corresponding to said content request and to return to said playlist generation platform, auction result information corresponding to digital content having won the auction if the auction has been won; - if the auction has been won, inform the content that has won the auction, by said playlist generation platform, said at least one digital display device corresponding to said free time slot.

[0005] Thanks to these provisions, the proposed digital display method is particularly efficient and economical in terms of processor capacity at the level of digital display devices. Indeed, the tasks to be carried out by digital display devices in the event of a winning auction are very limited and very fast, which contributes to near real-time operation. In addition, interaction with the programmatic advertising space sales platform is also simpler and faster, since it can be done from server to server.

[0006] In various embodiments of the digital display method, one and / or the other of the following arrangements may optionally be used (alone or in all their mutual combinations, optionally independently of the aforementioned arrangements):

[0007] - said programmatic platform for selling advertising space has in memory the digital content references likely to win the auction and the method further comprises: - have the digital display devices loaded in advance with the said digital content likely to win the auction, and to inform the content that won the auction, said playlist generation platform indicates to said at least one digital display device corresponding to said free time slot, which digital content won the auction among said digital content likely to win the auction: these provisions also contribute to the quasi-real-time operation at the level of the digital display devices, even when the connectivity of the digital display devices is not very good (for example if the digital display devices communicate with a cellular network such as a 3G or 4G network);

[0008] - the method further comprises: — transmitting by said playlist generation platform, to the digital display devices, loading addresses corresponding to the digital contents to be loaded respectively by said digital display devices; — load said digital contents by the digital display devices from said loading addresses;

[0009] - each playlist includes at least one series of naked content identifiers merics to read but does not include addresses for loading digital contents and the method further comprises: — generate by said playlist generation platform, for each digital display device, a loading manifest comprising at least digital content loading addresses; the synchronization of digital display devices with said playlist generation platform comprising: — query said playlist generation platform, at predetermined intervals terminated, by each digital display device, to determine whether said playlist generation platform has a new playlist and / or a new upload manifest corresponding to said digital display device; — if so, load said new playlist and / or said new loading manifest onto the digital display device; — if a new loading manifest has been loaded from the server, determining by said digital display device which new digital content(s) are referenced in said loading manifest; — and download by said digital display device, said new digital content(s) from the address(es) indicated in the new loading manifest;

[0010] - when a playlist has a free time slot, said playlist includes, for said free time slot, the identifiers of said digital content likely to win the auction, and the loading manifest corresponding to said playlist includes the loading addresses of said digital content likely to win the auction, and to inform of the content having won the auction, said platform (7) for generating playlists sends an order to activate said digital content having won the auction for said free time slot;

[0011] - the step of sending a content request is performed repeatedly for each free time slot, as long as the auction is not won;

[0012] - the step of sending a content request is carried out at the latest between T and 2T before the free time slot, T being the duration of the time slot preceding said free time slot;

[0013] - said playlist generation platform imposes time slots free when said playlist generation platform generates playlists based on display campaigns ordered independently of the programmatic advertising space sales platform;

[0014] - categories are assigned to digital content, said management platform nation of playlists assigns at least one prohibited category respectively to the free time slots based on the contents already assigned to the adjacent time slots, and during said step of sending a content request, said playlist generation platform indicates the prohibited categories to said programmatic advertising space sales platform;

[0015] - each digital display device is loaded in advance, only those of said digital content likely to win the auction which has a category other than said at least one category prohibited for the free time slots corresponding to this digital display device.

[0016] Furthermore, the present description also relates to a digital display system comprising digital display devices and a playlist generation platform, in which: - said playlist generation platform is adapted to generate playlists based on display campaigns, each playlist comprising information necessary for one or more of said digital display devices to display a series of digital contents during successive time slots, at least some of the playlists having free time slots not allocated to a specific digital content; - the digital display system is adapted to repeatedly synchronize the digital display devices with said playlist generation platform so that each digital display device has in memory the up-to-date playlist generated for it by said playlist generation platform; - for each free time slot of each playlist, corresponding to at least one digital display device, said playlist generation platform is adapted to send a content request to a programmatic advertising space sales platform adapted to issue an auction corresponding to said content request and to return to said playlist generation platform, auction result information corresponding to digital content having won the auction if the auction has been won; - said playlist generation platform is adapted to, if the auction has been won, inform the content having won the auction, said at least one digital display device corresponding to said free time slot.

[0017] In various embodiments of the digital display system, one and / or the other of the following arrangements may optionally be used (alone or in all their mutual combinations, optionally independently of the aforementioned arrangements):

[0018] - the system further comprises said programmatic sales platform advertising space, and said programmatic advertising space sales platform is adapted to send said auction to at least one programmatic advertising purchasing platform;

[0019] - in the digital display system: — the said programmatic advertising space sales platform stores the references of digital content likely to win the auction; — the digital display system is adapted to pre-load the digital display devices with said digital content likely to win the auction, — and to inform of the content having won the auction, said playlist generation platform is adapted to indicate to said at least one digital display device corresponding to said free time slot, which digital content has won the auction among said digital content likely to win the auction;

[0020] - in the digital display system: — said playlist generation platform is adapted to transmit to the digital display devices, loading addresses corresponding to the digital contents to be loaded respectively by said digital display devices; — the digital display devices are adapted to load said digital contents from said loading addresses;

[0021] - in the digital display system: — each playlist includes at least one series of identifiers of digital content to be played but does not include addresses for loading the digital content; — said playlist generation platform is adapted to generate, for each digital display device, a loading manifest comprising at least digital content loading addresses; — to synchronize the digital display devices with said playlist generation platform, each digital display device is adapted to interrogate said playlist generation platform at predetermined intervals, to determine whether said playlist generation platform has a new playlist and / or a new loading manifest corresponding to said digital display device and if so, to load said new playlist and / or said new loading manifest onto the digital display device; — said digital display device is adapted to, if a new loading manifest has been loaded from the server, determine which are the new digital contents referenced in said loading manifest and download said new digital contents from the address(es) indicated in the new loading manifest;

[0022] - when a playlist has a free time slot, said playlist includes, for said free time slot, the identifiers of said digital content likely to win the auction, and the loading manifest corresponding to said playlist includes the loading addresses of said digital content likely to win the auction, and to inform about the content that won the auction, said platform (7) of management generation of playlists is adapted to send an activation order for said digital content having won the auction for said free time slot;

[0023] - said playlist generation platform is adapted to send said request content repeatedly for each free time slot, until the auction is won;

[0024] - said playlist generation platform is adapted to send said request for content at the latest between T and 2T before the free time slot, T being the duration of the time slot preceding said free time slot;

[0025] - said playlist generation platform is configured to impose free time slots when said playlist generation platform generates playlists based on display campaigns ordered independently of the programmatic advertising space sales platform;

[0026] - categories are assigned to digital content, said management platform playlist generation platform is configured to assign at least one prohibited category respectively to the free time slots based on the contents already assigned to the adjacent time slots, said playlist generation platform indicates the prohibited categories to said programmatic advertising space sales platform and when sending a content request;

[0027] - each digital display device is adapted to charge in advance only those of said digital contents likely to win the auction which have a category other than said at least one category prohibited for the free time slots corresponding to this digital display device. Brief description of the drawings

[0028] Other characteristics and advantages of the digital display method and of the digital display system will appear during the following description of one of their embodiments, given by way of non-limiting example, with reference to the attached drawings.

[0029] On the drawings: Fig.l

[0030] [fig.l] [fig.l] is a schematic view showing a digital display system according to one embodiment. Fig. 2

[0031] [fig-2] [fig.2] is a schematic view showing an example of a playlist.

[0032] More detailed description

[0033] In the various figures, the same references designate identical or similar elements.

[0034] [fig.l] shows a digital display system 1 comprising several digital display devices 2 (DISP). The digital display devices may be in large number, possibly several thousand, possibly distributed over a large geographical area.

[0035] Each display device 2 comprises a control device 3 (CTRL) such as a microcomputer or the like, which controls a digital screen 4.

[0036] The control device 3 executes a digital content player 5 (PL) (software module executed by the control device 3) and also executes a synchronization software module 6 (SYNC).

[0037] The digital display system 1 further comprises a playlist generation platform 7 (PL SERV), which is common to the aforementioned digital display devices 2. The playlist generation platform 7 is a software package that can be executed on one or more servers.

[0038] The platform 7 for generating playlists notably executes an engine 8 (ENG) for generating lists of contents and loading manifests, as will be explained in more detail below.

[0039] The synchronization module 6 of each digital display device 2 communicates with the platform 7 for generating playlists and, if applicable, with other resources, possibly on the Internet 9 (INT). In the embodiment shown, the digital display devices 2 communicate with the platform 7 for generating playlists and with said other resources via at least one proxy server 13 (PROX) or proxy server.

[0040] This communication can be done via any wide area network (WAN). For example, in many cases this communication can be done via a mobile telephone network (broadband cellular network, for example 3G or 4G type). Of course, any other mode of communication is possible.

[0041] The engine 8 is adapted to generate repetitively and / or as a function of certain generating events (modification of programming, contents, etc.) playlists according to the current display campaigns. This generation of playlists is carried out as a function of the reservations made by the advertisers concerning the different display devices 2, as a function of the digital contents to be played for these display campaigns and as a function of the available digital display devices.

[0042] Each playlist is intended to be read by one or more of said digital display devices 2.

[0043] Each playlist may comprise at least one series of identifiers of digital contents to be read sequentially, over one or more predetermined time periods, these digital contents being assigned to time slots successive. These time slots may all be of the same duration, or not. The duration T of these time slots may be between 5 and 20 s, for example 10 s.

[0044] According to one embodiment, the reading list does not include loading addresses of the digital contents or digital fingerprints of the digital contents; it is therefore a document representing a low volume of data.

[0045] The engine 8 is further adapted to generate repetitively and / or as a function of certain generating events (modification of programming, contents, etc.), for each digital display device, a loading manifest comprising at least loading addresses of the digital contents referenced in the loading list. Each loading manifest may further comprise, for each digital content, the identifier included in the reading list.

[0046] Each loading manifest may further comprise at least one reference digital fingerprint for each digital content referenced in said loading manifest. According to one example, the digital fingerprint may be a checksum, for example of the “MD5” type. According to another example, the digital fingerprint may be a digital signature of the “GPG” type. According to a third example, the loading manifest may further comprise two reference digital fingerprints for each digital content, in particular a checksum, for example of the “MD5” type, and a more complex digital signature, for example of the “GPG” type.

[0047] The frequency of generation of playlists and loading manifests by the engine 8 may vary depending on the speed of arrival of new reservations or modifications of reservations by advertisers. This frequency may be up to once every few minutes, or even higher frequencies, knowing that some of the reservations may be made by automatic online auctions. As explained previously, certain updates of playlists are made without changing the loading manifest when the modifications concern, for example, the order or frequency of reading of the digital content, or even the conditions for reading the digital content.

[0048] The synchronization modules 6 of the digital display devices 2 are adapted to update their playlists and loading manifests, from the engine 8.

[0049] This update may include the following steps: cl) The synchronization module 6 of the display device 2 polls the engine 8 by sending a request at predetermined intervals, to determine whether the engine 8 has a new playlist and / or a new loading manifest corresponding to the digital display device 2. The polling frequency of the engine 8 may be fixed (e.g. every few minutes) or determined by a previously downloaded playlist and / or load manifest from the engine 8. For example, the frequency of polling the engine 8 for playlists may be fixed (e.g. every few minutes, such as every 5 minutes) and the frequency of polling the engine 8 for load manifests may be included in the playlists. The playlists and load manifests may be timestamped and to determine if the engine 8 has a new playlist corresponding to the digital display device 2, the synchronization module 6 may send a request to the engine 8 to receive the timestamp of the current playlist for the digital display device 2.If this timestamp is newer than the timestamp of the last playlist downloaded by digital display device 2, then it is determined that engine 8 has a new playlist corresponding to digital display device 2. The same is done for the loading manifests. c2) If it is determined that the engine 8 has a new playlist corresponding to the digital display device 2 and / or a new loading manifest, the synchronization module 6 loads the new playlist and / or the new loading manifest from the engine 8 (by sending a request to receive the new playlist and / or the new loading manifest). c3) If a new loading manifest has been loaded from the engine 8, the synchronization module 6 of the digital display device 2 determines which are the new digital contents referenced in the new loading manifest. This determination can be made for example by comparing the digital fingerprints of the digital contents referenced in the new loading manifest with the digital fingerprints of the digital contents already present in the memory of the digital display device 2. c4) The synchronization module 6 of the digital display device 2 then downloads said new digital content(s) from the URL address(es) corresponding to each digital content indicated in the new loading manifest. Generally speaking, this download can be done via the Internet 9. The URL addresses in question can correspond to the playlist generation platform 7, to another server specific to the operator of the playlist generation platform 7 or to another location on the Internet.

[0050] The reader 5 of each digital display device 2 is adapted to read the digital contents corresponding to its current reading list (last reading list loaded by the synchronization module 6) and to display these digital contents on the digital screen 4 of the digital display device 2.

[0051] In steps (cl) and (c2), the synchronization module 6 of each device digital display 2 always sends its requests to the same URL address which is specific to the digital display device 2.

[0052] In steps (cl) and (c2), the synchronization module 6 and the motor 8 can advantageously communicate in encrypted form, for example using the “https” protocol.

[0053] In step (c4), the synchronization module 6 of the digital display device 2 can determine a calculated digital fingerprint of the newly downloaded digital content, check whether the calculated digital fingerprint corresponds to the reference digital fingerprint contained in the loading manifest and validate the downloaded digital content only if the calculated digital fingerprint corresponds to the reference digital fingerprint. If the downloaded digital content is not validated, it is destroyed. If the download manifest contains two (or more) digital fingerprints for at least some digital content, this validation can be carried out for the different digital fingerprints of the digital content, sequentially or in parallel.

[0054] In step (c4), the synchronization module 6 of the digital display device 2 can download the new digital contents in an unencrypted manner, for example using the “http” protocol.

[0055] In step (c4), the synchronization module 6 of the digital display device 2 can, in one embodiment, download the new digital contents in pieces.

[0056] As shown in [fig.2], at least some of the playlists PL generated by the engine 8 have free time slots FTS, not assigned to a predetermined digital content, while the other time slots are assigned to predetermined time slots, for example contents A, B, C, D, E in the example of [fig.2].

[0057] These free FTS time slots are used for programmatic advertising, therefore auctioned by an automatic auction process.

[0058] For this purpose, as shown in [fig. 1], the platform 7 for generating playlists may include a content programmer module 15 (AD SCH) which communicates with a programmatic platform 20 for selling advertising space (SSP).

[0059] The programmatic platform 20 for selling advertising space is a software package that can be executed on one or more servers. It can in particular comprise a content server module 21 (ADSERV), a data exchange module 22 (EXCH) and a content control module 23 (AD CTRL). The data exchange module 22 is adapted to communicate with one or more programmatic platforms 30 for purchasing advertising space (DSP), so as to issue auctions for free time slots and receive auction result information in return. These data exchanges can be done using a standardized data exchange protocol, for example the “OPEN RTB” protocol.

[0060] For each free time slot FTS of each playlist PL, corresponding to at least one digital display device 2, the content programmer module 15 sends a content request to the content server module 21 of the programmatic platform 20 for selling advertising space. The content server module 21 then sends to the programmatic platform(s) 30 for purchasing advertising space, via the data exchange module 22, an auction corresponding to said content request.

[0061] The programmatic platform(s) 30 for purchasing advertising space then proceed with the auction process (real-time bidding) and if the auction has been won, return to said content server module 21, via the data exchange module 22, auction result information corresponding to digital content having won the auction.

[0062] If the auction has been won, the content server module 21 transmits the auction result information to the content programmer module 15 which then informs the digital content having won the auction, the digital display device 2 corresponding to the free time slot FTS having been the subject of the auction. This sending of information to the digital display device 2 can be carried out via the aforementioned proxy server 13 and / or any other intermediate proxy server between the digital display device 2 and the platform 7 for generating playlists.

[0063] The digital contents present on the programmatic platform(s) 30 for purchasing advertising space may already be known in advance to the programmatic platform 20 for selling advertising space, by exchange of data between the programmatic platform(s) 30 for purchasing advertising space and the programmatic platform 20 for selling advertising space, for example each time that new digital content is referenced on the programmatic platform(s) 30 for purchasing advertising space. The digital contents in question are validated during a moderation process, and the validated digital contents are referenced in the aforementioned content control module 23. This content control module 23 communicates with the engine 8, which thus references all the digital contents likely to win an auction.Engine 8 thus includes, in the free FTS time slots of each playlist, the references of all content likely to win auctions, and the references of this content are also included in the loading manifest of each device. digital display devices 2, at least one of which has a free FTS time slot. Using these loading manifests, the digital display devices 2 are loaded in advance with said digital content that is likely to win an auction.

[0064] Thus, when the engine 8 sends to the digital display device 2 the information of the content having won the auction, the content programmer module 15 sends a very short and very fast message containing a simple order to activate said digital content having won the auction for said free time slot, and this content can almost immediately be displayed by the digital display device 2 since it is already in memory in the digital display device.

[0065] The entire process of auctioning and activating the digital content that has won the auction can therefore be carried out in a very short time, typically a fraction of a second to a few seconds. Typically, the step of sending a content request by the content scheduling device 15 can be carried out at the latest between T and 2T before the free time slot, T being the duration of the time slot preceding said free time slot (i.e. generally the duration common to all the time slots of the playlist).

[0066] It will be noted that when the auction has not been won following the auction process described above, the free time slot FTS can be re-auctioned in the same manner as described above, if there is enough time remaining before the start time of said free time slot FTS.

[0067] The playlist generation platform 7 may impose free FTS time slots when said playlist generation platform 7 generates playlists based on display campaigns ordered independently of the programmatic advertising space sales platform 20. For example, the playlist generation platform 7 may impose a certain percentage of free FTS time slots, which it may distribute, for example, evenly. In particular, the playlist generation platform 7 may respectively impose percentages of free FTS time slots according to the day and / or according to the time slot within the day, and said playlist generation platform 7 may distribute these free time slots, for example, evenly within the day or within the time slot within the day.

[0068] Categories can be assigned to digital contents. Said playlist generation platform 7 can assign at least one prohibited category respectively to the free FTS time slots based on the contents already assigned to the adjacent time slots, and when sending a content request, said playlist generation platform 7 indicates the prohibited categories to said programmatic advertising space sales platform 20.

[0069] In this case, it is possible to load in advance to each digital display device 2 only those of said digital contents likely to win the auction which have a non-prohibited category for the free FTS time slots corresponding to this digital display device 2.

Claims

Claims

1. Digital display method for controlling the display of digital content by digital display devices (2), comprising: - generating by a platform (7) for generating playlists, playlists according to display campaigns, each playlist comprising information necessary for one or more of said digital display devices (2) to display a series of digital content during successive time slots, at least some of the playlists having free time slots not assigned to a specific digital content; - repeatedly synchronizing the digital display devices (2) with said playlist generation platform (7) so that each digital display device (2) has in memory the up-to-date playlist generated for it by said playlist generation platform (7); - for each free time slot of each playlist, corresponding to at least one digital display device (2), sending a content request by said playlist generation platform (7), to a programmatic advertising space sales platform (20), said programmatic advertising space sales platform (20) being adapted to issue an auction corresponding to said content request and to return to said playlist generation platform (7), auction result information corresponding to a digital content having won the auction, if the auction has been won; - if the auction has been won, informing the digital content having won the auction, by said platform (7) for generating playlists, said at least one digital display device (2) corresponding to said free time slot.

2. Method according to claim 1, in which said programmatic platform (20) for selling advertising space has in memory references of digital content likely to win the auction and the method further comprises: - having said digital content likely to win the auction loaded in advance to the digital display devices (2), and to inform the content having won the auction, said playlist generation platform (7) indicates to said at least one device digital display (2) corresponding to said free time slot, which digital content won the auction among said digital content likely to win the auction.

3. Method according to claim 2, further comprising: - transmitting by said platform (7) for generating playlists, to the digital display devices (2), loading addresses corresponding to the digital contents to be loaded respectively by said digital display devices (2); - loading said digital contents by the digital display devices (2) from said loading addresses.

4. Method according to claim 3, wherein each playlist comprises at least one series of identifiers of digital contents to be played but does not comprise loading addresses of the digital contents and the method further comprises: - generating by said playlist generation platform (7), for each digital display device (2), a loading manifest comprising at least loading addresses of digital contents; synchronizing the digital display devices (2) with said playlist generation platform (7) comprising: - interrogating said playlist generation platform (7), at predetermined intervals, by each digital display device (2), to determine whether said playlist generation platform (7) has a new playlist and / or a new loading manifest corresponding to said digital display device (2);- if so, loading said new playlist and / or said new loading manifest onto the digital display device (2) - if a new loading manifest has been loaded from the server (7), determining by said digital display device (2) which are the new digital content(s) referenced in said loading manifest; - and downloading by said digital display device (2), said new digital content(s) from the address(es) indicated in the new loading manifest.;

5. A method according to claim 4 in combination with claim 2, wherein when a playlist comprises a free time slot, said playlist comprises, for said free time slot, the identifiers of said digital contents likely to win the auction, and the loading manifest corresponding to said playlist includes the loading addresses of said digital contents likely to win the auction, and to inform of the content having won the auction, said playlist generation platform (7) sends an activation order of said digital content having won the auction for said free time slot.

6. A method according to any preceding claim, wherein the step of sending a content request is performed repeatedly for each free time slot, until the auction is won.

7. A method according to any preceding claim, wherein the step of sending a content request is performed at the latest between T and 2T before the free time slot, T being the duration of the time slot preceding said free time slot.

8. A method according to any preceding claim, wherein said playlist generation platform (7) imposes free time slots when said playlist generation platform (7) generates playlists based on display campaigns ordered independently of the programmatic advertising space sales platform (20).

9. Method according to any one of the preceding claims, wherein categories are assigned to the digital contents, said playlist generation platform (7) assigns at least one prohibited category respectively to the free time slots based on the contents already assigned to the adjacent time slots, and during said step of sending a content request, said playlist generation platform (7) indicates the prohibited categories to said programmatic advertising space sales platform (20).

10. Method according to claim 9 in combination with claim 2, in which each digital display device (2) is loaded in advance only those of said digital contents likely to win the auction which have a category other than said at least one category prohibited for the free time slots corresponding to this digital display device (2).

11. Digital display system comprising display devices

12.

13. digital (2) and a platform (7) for generating playlists, in which: - said platform (7) for generating playlists is adapted to generate playlists according to display campaigns, each playlist comprising information necessary for one or more of said digital display devices (2) to display a series of digital contents during successive time slots, at least some of the playlists having free time slots not allocated to a determined digital content; - the digital display system is adapted to repeatedly synchronize the digital display devices (2) with said playlist generation platform (7) so that each digital display device (2) has in memory the up-to-date playlist generated for it by said playlist generation platform (7); - for each free time slot of each playlist, corresponding to at least one digital display device (2), said playlist generation platform (7) is adapted to send a content request to a programmatic advertising space sales platform (20) adapted to issue an auction corresponding to said content request and to return to said playlist generation platform (7), auction result information corresponding to a digital content having won the auction, if the auction has been won; - said platform (7) for generating playlists is adapted to, if the auction has been won, inform of the digital content having won the auction, said at least one digital display device (2) corresponding to said free time slot. The digital display system of claim 11, further comprising said one programmatic advertising space selling platform (20), wherein said programmatic advertising space selling platform (20) is adapted to send said auction to at least one programmatic advertising buying platform (30). A digital display system according to claim 12, wherein: - said programmatic platform (20) for selling advertising space has in memory references of digital content likely to win the auction; - the digital display system is suitable for charging in advance to digital display devices (2) said digital content likely to win the auction, - and to inform of the content having won the auction, said platform (7) for generating playlists is adapted to indicate to said at least one digital display device (2) corresponding to said free time slot, which digital content has won the auction among said digital contents likely to win the auction.

14. A digital display system according to claim 13, wherein: - said platform (7) for generating playlists is adapted to transmit to the digital display devices (2), loading addresses corresponding to the digital contents to be loaded respectively by said digital display devices (2); - the digital display devices (2) are adapted to load said digital contents from said loading addresses.

15. A digital display system according to claim 14, wherein: - each playlist includes at least one series of identifiers of digital content to be played but does not include addresses for loading the digital content; - said platform (7) for generating playlists is adapted to generate, for each digital display device (2), a loading manifest comprising at least addresses for loading digital content; - to synchronize the digital display devices (2) with said playlist generation platform (7), each digital display device (2) is adapted to interrogate said playlist generation platform (7) at predetermined intervals, to determine whether said playlist generation platform (7) has a new playlist and / or a new loading manifest corresponding to said digital display device (2) and if so, to load said new playlist and / or said new loading manifest onto the digital display device (2) - said digital display device (2) is adapted to, if a new loading manifest has been loaded from the server (7), determine which are the new digital contents referenced in said loading manifest and download said new digital contents from the address(es) indicated in the new loading manifest.

16. Digital display system according to claim 15 in combination with claim 13, wherein when a playlist comprises a free time slot, said playlist comprises, for said free time slot, the identifiers of said digital contents likely to win the auction, and the loading manifest corresponding to said playlist comprises the loading addresses of said digital contents likely to win the auction, and to inform of the content having won the auction, said playlist generation platform (7) is adapted to send an activation order of said digital content having won the auction for said free time slot.

17. A digital display system according to any one of claims 11 to 16, wherein said playlist generation platform (7) is adapted to send said content request repeatedly for each free time slot, as long as the auction is not won.

18. Digital display system according to any one of claims 11 to 17, wherein said platform (7) for generating playlists is adapted to send said content request at the latest between T and 2T before the free time slot, T being the duration of the time slot preceding said free time slot.

19. A digital display system according to any one of claims 11 to 18, wherein said playlist generation platform (7) is configured to impose free time slots when said playlist generation platform (7) generates playlists based on display campaigns ordered independently of the programmatic advertising space sales platform (20).

20. A digital display system according to any one of claims 11 to 19, wherein categories are assigned to the digital contents, said playlist generation platform (7) is configured to assign at least one prohibited category respectively to the free time slots based on the contents already assigned to the adjacent time slots, said playlist generation platform (7) indicates the prohibited categories to said programmatic advertising space sales platform (20) and when

21. of sending a content request. Digital display system according to claim 20 in combination with claim 13, wherein each digital display device (2) is adapted to load in advance only those of said digital contents likely to win the auction which have a category other than said at least one prohibited category for the free time slots corresponding to this digital display device (2).

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