FR3038804A1 - METHOD AND DEVICE FOR SECURING DIGITAL BROADCAST OF AUDIOVISUAL CONTENT, COMPUTER PROGRAMS AND CORRESPONDING MEDIA FOR STORAGE. - Google Patents

Abstract

The invention proposes a method for securing digital broadcasting of audiovisual content in a digital broadcasting network, said content being generated by a main (10) and / or backup (11) equipment of a headend of said network. network. According to the invention, said method, implemented within a securing device (12) of said headend, comprises: a step of recording (20) said audiovisual content, as and when generation), and • a provisioning step (21), for broadcasting in said network, of at least a portion (Content 3) previously recorded of said audiovisual content when a cutoff, of a duration greater than a threshold predetermined, generation by said main equipment (10) and backup (11) is detected by said securing device (12).

Description

Method and device for securing digital broadcasting of audiovisual content, computer programs and corresponding storage media. 1. Field of the invention

The field of the invention is that of the broadcasting of digital content, of the audiovisual type in particular, and more particularly of the continuity of service, or the securing of this broadcast, in the case where the main source of broadcasting (as well as the backup source if any) becomes unavailable. The invention applies in particular, but not exclusively, to multimedia streams that comply with the DVB-T or DVB-T2 ("Digital Video Broadcasting - Terrestrial") broadcast standards for "digital terrestrial video broadcasting". 2. Prior Art

Currently, the equipment generating the audiovisual sources, for example audiovisual coders, are generally secure, at the headend of the broadcast network, by one or more separate equipment, powered by the same audiovisual content produced in the studio. In case of loss of the main source, for example due to a malfunction of the generating equipment, it is expected that a backup equipment will take over, and it is then a source called "emergency" which is broadcast.

On the other hand, when all the sources (main and backup) are no longer available, the service is no longer broadcast by the headend. This is reflected at each broadcast site by an interruption of the service or, at best, by the substitution of the interrupted program by a substitute audiovisual file previously loaded and stored in the receiver of each broadcast site.

These current techniques however have several disadvantages: • all broadcast sites must be provided with storage and reading equipment, in order to be able to broadcast the intended substitution file in the event of interruption of the broadcast by the headend; • all sites must be connected to central equipment to obtain the substitution file; • the substitution file must be sent by this central device in as many copies as there are broadcast sites in the network; • a substitution file must be permanently available in each receiving equipment of broadcast sites, to compensate for any interruption of unplanned service, its content can hardly be related to the news, or the program interrupted.

There is therefore a need for a backup technique to overcome these disadvantages of the prior art, while being simple to implement and inexpensive. 3. DISCLOSURE OF THE INVENTION The invention proposes a new solution that does not have all of these disadvantages of the prior art, in the form of a method of securing digital broadcasting of audiovisual content in a digital broadcasting network, the audiovisual content being generated by a main equipment and / or by at least one backup equipment of at least one headend of the digital broadcasting network.

According to the invention, the method is implemented within a headend security device and comprises: a step of recording the audiovisual content, as and when it is generated by at least one of the main and backup equipment, and • a step of providing, for broadcasting in the digital broadcasting network, at least a previously recorded portion of the audiovisual content when a cutoff, of a duration greater than a predetermined threshold , the generation by the main and backup equipment is detected by the security device.

Thus, according to its various embodiments, the invention is based on a new and inventive approach to continuity of service in a context of digital broadcasting of audiovisual content when the "main" and "backup" sources are unavailable, allowing providing, at the head end, a plurality of previously recorded portions of the audiovisual content, during the unavailability of the main and backup sources.

To do this, a security device (integrated or connected to the headend) records audiovisual content, as and when it is generated by one or more pieces of equipment at the headend, and provides its recording for broadcast in the network. network when it detects a break (of a predetermined duration) at all content generation equipment, also called source / main equipment and backup source / equipment.

In the event of unavailability of the main and emergency sources, the invention proposes, according to its various embodiments, an additional backup service capable of maintaining the service, from the headend, by broadcasting the most recent contents. from the program.

According to a particular characteristic of the invention, the recording step comprises the following substeps, implemented in a frame encapsulation module of the security device: • reception, coming from at least one of the equipment main and backup, audiovisual content generated; Generating a plurality of frames from the received audiovisual content; and a sub-step, implemented in a management module of the security device, for recording in at least one circular memory of the device for securing the plurality of generated frames, delivering at least one backup loop, a predetermined duration of the audiovisual content received.

Thus, according to this embodiment of the invention, the security method makes it possible to "capture", via a security device, permanently the content generated by one and / or the other of the main and emergency equipment. , then to associate with this content (for example via a frame encapsulation module of the security device), if necessary, additional information (structure information, timestamp, ...) before saving it (for example via a management module of the security device). The backup is done over a predefined time, so that it can provide portions of content of predetermined size. When the security device detects the unavailability of the main and backup sources, the recording is stopped and the main source is replaced by the frames transposed cyclically over a defined period of time, in the form of backup "loops".

According to a particular aspect of the invention, the provisioning step is implemented until detection of a recovery, at least a predetermined duration, of the generation of the audiovisual content by the main equipment and / or emergency equipment.

Thus, according to this embodiment of the invention, the security method ensures continuity of service for the duration of the unavailability of the main and backup sources, by monitoring the resumption of the generation of the content by the one or the other main or emergency equipment.

In particular, the generation substep comprises a sub-step of enriching the audiovisual content received by at least one enrichment information belonging to the group comprising: a time stamping information representative of the date of reception of the audiovisual content; • information representative of the address of the source of the audiovisual content; • information representative of the destination address or addresses of the audiovisual content; An identifier for grouping a plurality of audiovisual contents.

Thus, according to this embodiment of the invention, the security method makes it possible to enrich the content received with additional information (such as, for example, the date of reception), in particular to facilitate reading, by the reading module, frames generated by the frame encapsulation module. For example, the reading module can actually use the reception dates to replay the output content of the security device under the same conditions as when receiving the input content of the security device.

According to a particular characteristic of the invention, the recording step is interrupted during the supply step. Indeed, the supply step being implemented when a failure of the main and emergency equipment is detected, there is by definition no more correct signal to be recorded at this time. The recording of the content generated by one and / or the other of the main and emergency equipment resumes for example as soon as they are again in service, in order to anticipate a possible subsequent failure.

According to one particular aspect of the invention, the provisioning step comprises a substep, implemented in a monitoring module of the security device, for monitoring the audiovisual content generated by the main and / or backup equipment, delivering a cut-off alert when the cut is detected.

Thus, according to this embodiment of the invention, the security method makes it possible to monitor the content generated by the backup equipment (or according to a first variant the content generated by the main equipment, or according to a second variant the contents generated respectively by the main and back-up equipment), so as to detect a significant cut-off (that is to say, for example, even when the error correction mechanisms do not make it possible to restore the generation of the content) in order to enable the provision of content by the security device during the unavailability of the main and backup sources.

In particular, when a main equipment is actually "rescued" by emergency equipment, the method according to this embodiment of the invention only monitors the content generated by this backup equipment, because it is only in the case where the latter becomes unavailable that the security device provides the content previously saved. On the other hand, if there is no backup equipment, or if it can not perform its backup function, the method according to this embodiment can monitor the content generated by the main equipment to remedy any failure of the latter.

To do this, the monitoring module of the security device detects the breaks / interruptions and outgoing flows of the monitored equipment and informs for example the management module and the reading module of the security device via a warning of cut.

For example, break detection in the stream can monitor all or part of the stream components. The "FEC" (for "Forward Error Correction" in English) can be ignored for example.

In addition, a detection threshold can be used so as not to detect a break / cut that can be corrected by FEC.

Finally, the breaking / breaking detection can also be implemented using a time criterion, such as the absence of frames at the input of the monitoring module since T seconds.

In particular, the provisioning step comprises the following substeps, implemented in a read module of the security device, on receipt of the cut-off alert issued by the monitoring module: • obtaining at least one backup loop; Detection of at least one enrichment information associated with at least one frame of the backup loop, and, if the detection is positive, processing of the detected enrichment information delivering at least a portion of audiovisual content intended for broadcast in the digital broadcast network.

Thus, according to this embodiment of the invention, the security method uses the frames stored by the management module to reconstruct the stream rescued at the output, via a read module of the security device. To do this, the reading module "plays" the active backup loop continuously, and changes the backup loop on notification of the management module, so as to continuously provide a replacement content to the multiplexer of the headend for dissemination in the broadcast network.

In addition, the reading module can use, for example, reception dates inserted (by the frame encapsulation module) into the saved frames to replay the output content of the security device under the same conditions as during the reception. input content of the security device. The invention also relates to a device for securing digital broadcasting of audiovisual content in a digital broadcasting network, the audiovisual content being generated by a main equipment and / or by at least one backup equipment of at least one head of the digital broadcast network. According to the invention, the security device is integrated and / or attached to at least one headend of the digital broadcasting network and comprises the following means: • monitoring means, in the form of a monitoring module, of the audiovisual content generated by the main and back-up equipment, delivering a cut-off alert when a cut-off, of a duration greater than a predetermined threshold, of the generation by the main and backup equipment is detected; Frame encapsulation means, in the form of a frame encapsulation module, comprising means for receiving, from at least one of the main and backup equipment, the audiovisual content generated and the means of generating a plurality of frames corresponding to the received audiovisual content; Management means, in the form of a management module, comprising means for recording, in at least one circular memory, the plurality of frames generated by the frame encapsulation module, delivering at least one loop safeguarding, for a predetermined duration, the audiovisual content received; Reading means, in the form of a reading module, activated upon receipt of the cut-off alert issued by the monitoring module, delivering at least a portion of the audiovisual content saved for broadcast in the broadcast network; digital. The invention also relates to a computer program for implementing a security method as described above when this program is executed by a processor. Finally, the invention relates to a computer-readable and non-transitory storage medium, storing a computer program comprising instructions executable by a processor to implement a security method as described above. 4. List of Figures Other features and advantages of the invention will appear more clearly on reading the following description of a particular embodiment, given as a simple illustrative and non-limiting example, and the accompanying drawings, among which: FIG. 1 illustrates an exemplary system in which the invention can be implemented, according to a particular embodiment; Figure 2 shows the main steps of a security method, according to a particular embodiment of the invention; FIG. 3 shows an example of enrichment of the frames and of the direction of the diffusion carousel, according to one particular embodiment of the invention; FIG. 4 illustrates an example of the various modules constituting a security device, according to one embodiment of the invention; FIG. 5 illustrates an example of a simplified architecture for a security device, according to one embodiment of the invention. 5. Description of an embodiment of the invention 5.1 General principle

The general principle of the invention is based on the recording, by an equipment of a headend, portions of audiovisual content as it is being generated, in order to broadcast, in a digital broadcasting network, these portions recorded when both the main equipment and the backup equipment are no longer able to provide content for broadcast in the network.

For example, and as illustrated in FIG. 1, the invention is implemented in a security device 12, within the headend (or attached to the headend), so as to "replace" the equipment generation of content (typically a main equipment 10 and / or a backup equipment 11) when unavailable.

Thus, unlike the techniques of the prior art where the provision of alternative audiovisual content is implemented at each broadcast site, the invention, according to its different embodiments, provides a content of substitution (Content 3) at the headend. The invention thus makes it possible to simplify in a very significant manner the implementation of such a substitution service, by processing the content generation cuts at the head end of the network, and no longer at the level of each broadcasting site as in the current solutions.

In addition, the substitute content (Content 3) is strongly related to the content (Content 1 or Content 2) whose broadcast has been interrupted since it corresponds to a recent recording of this content, thus improving the service for the user.

To do this, the security device 12 records, in real time, in the form of "backup" loops (for example in circular buffers, as detailed below according to one embodiment), portions of the audiovisual content generated by one or the other main or backup equipment, from the "Audio-Visual Source".

Then, when the security device 12 detects a cut in the generation of the audiovisual content to be broadcast both at the main equipment and the backup equipment, it transmits to the multiplexer 13 previously recorded portions of the audiovisual content ( Content 3).

At the output of the multiplexer 13, the audiovisual content to be broadcast (Content 4) therefore corresponds to: • the content (Content 1) generated by the main equipment 10, in normal operation; The content (Content 2) generated by the backup equipment 11 when the main equipment 10 is unavailable; The content (Content 3) generated by the security device 12 when both the main equipment 10 and the emergency equipment 11 are unavailable.

FIG. 1 thus illustrates the integration of the technique into a headend, such as a "remote backup" device. In this example, the equipment (main and backup 11) are installed in the studio and the security device 12 of the invention is for example located in a remote room. With this configuration, a generalized failure of the studio equipment does not result in a stop of the services, because the security device 12 according to the invention ensures the supply to the multiplexer of the most recent contents, for their dissemination in the network replacing the interrupted audiovisual content. 5.2 Description of an embodiment of the security method

We will now describe, in relation to FIG. 2, the main steps of the security method, according to one embodiment of the invention, implemented by a security device in a system as illustrated in FIG.

Thus, it is considered that the headend has a main content generation equipment (Content 1) from the audiovisual source and a content generation backup equipment 11 (Content 2) from the same audiovisual source, and a multiplexer 13 taking as input audiovisual content generated by one or other of the equipment 10 and 11, when these are available, to provide audiovisual content (Content 4) ready to be broadcast in the network digital broadcasting.

According to this embodiment of the invention, the security method records, during a recording step 20, the audiovisual content (Content 1/2) generated by one or the other of the devices 10 and 11, according to two embodiments. This recording is detailed below, in connection with the description of an embodiment of the security device and the various modules that compose it.

This recording step 20 is thus mainly implemented for example by a management module of the security device, as described in more detail below, and is followed by a step 21 of providing at least one portion ( Content 3) previously saved. This supply step 21 is activated by the detection of a cut-off, of a duration greater than a predetermined threshold, of the generation by said main and backup equipment. Thus, when the security method detects (for example via a monitoring module of the security device, as hereinafter described in more detail) a breaking / breaking of the generation of content for the two devices 10 and 11, the portions of content previously recorded during the recording step 20 are used to be provided to the multiplexer 13, for the purpose of broadcasting a substitution content in the broadcast network, replacing the interrupted content. 5.3 Description of an embodiment of the security device

We will now describe, in relation to FIG. 4, the different modules making up the security device 12, according to one embodiment of the invention.

According to this exemplary embodiment, the security device 12 comprises the following four main modules: a monitoring module 120, a frame encapsulation module 121, a management module 122 and a read module 123.

The monitoring module 120 is in charge of monitoring the flow (Content 2) at the output of the emergency equipment 11 and notifies the absence or the presence of an output content of this emergency equipment to the management module 122 and to the reading module 123.

According to another variant, if the emergency equipment 11 is not implemented in the system for example, the monitoring module 120 is responsible for monitoring the flow (Content 1) at the output of the main equipment 10.

Thus, the monitoring module 120 detects the breaks / breaks and resumption of flow, so as to trigger the supply of the content of the substitution (Content 3) if necessary.

Failure detection in the flow can be implemented by monitoring all or part of the flow components (for example, the FEC component can be ignored), and a detection threshold can be used in order not to detect a break can be corrected by FEC for example. Failure detection can also be done using a time criterion such that a cut is detected when no frame is received by the securing device since T seconds, for example.

Once a cut is detected, the monitoring module 120 informs the management module 122 so that it manages the backup loops to be used by the reading module 123. The latter is also informed directly of the cut by the monitoring module.

The security device 12 also comprises a frame encapsulation module 121, in charge of creating the frames to be backed up, from the source stream (Content 1/2). For example, the frame encapsulation module 121 may filter a portion of the received stream (for example, the bits / pad bytes may be deleted in order to optimize the memory space) and / or enrich it with additional information, such as example a timestamp (receipt date).

FIG. 3 shows an example of encapsulated frames, in the form of a carousel in which the frames enter through the "IN" input and emerge, for delivery to the management module 122, via the "OUT" output.

In this example illustrated in FIG. 3, timestamp information H and data D are added in order to enrich the content, for its subsequent use by the management and reading modules.

The frames encapsulated by the frame encapsulation module 121 are then transmitted to the management module 122, in charge of saving them and transmitting them to the reading module 123.

Thus, the management module 122 manages the backup and the life of the encapsulated frames. For example, this management module 122 stores several backup loops for a content received at the input of the security device, a backup loop corresponding for example to a circular buffer of frames.

The management module 122 also manages the choice of the so-called "active" backup loop that must be used by the reading module 123. Indeed, each "active" backup loop must contain a minimum duration of content, without interruption detected. , so as to provide quality substitute content. The management module 122 thus selects the most recent valid loop as "active" loop for the reading module 123.

The management module 122 also manages the coherence, in a loop, between the different elements constituting a stream (several IP addresses per port for example, in the case of an IP content).

Finally, the management module 122 erases the oldest loops, so that the replacement content is as recent as possible, when an interruption of the broadcast is detected.

The security device 12 also comprises a read module 123, which uses the frames stored by the management module 122 to reconstruct a content of substitution (Content 3) output. To do this, the reading module 123 "plays" the "active" backup loop (selected by the management module 122) continuously and changes "active" backup loop on notification of the management module 122.

In addition, the reading module 123 uses the enrichment information (added by the frame encapsulation module 121), such as the reception dates, to "replay" the output stream (Content 3) in the same way. conditions that the stream received at the input of the security device 12 (Content 1/2).

Finally, the reading module can also modify the frames of the "active" backup loop to play, as for example in the case of an input type IP stream. Thus, the read module 123 can modify the IP addressing and / or the port, when its parameters are different between the read module 123 and the main / backup generation equipment. The read module 123 can also modify the TAG VLAN (for local virtual network), if necessary. These modifications may indeed be necessary so that the content provided by the security device 12 is consistent with the content interrupted and properly interpreted by the multiplexer 13, in charge of broadcasting content (Content 4) in the broadcast network , from the content (Content 3) received as input from the security device 12. 5.4 Other features and variant embodiments

According to an alternative embodiment, the frame encapsulation module 121 comprises a sub-module for detecting audiovisual content, making it possible to identify the broadcasts within the program being broadcast. Thus, the frame encapsulation module 121 can format the frames so as to allow broadcast storage / storage. In this case, the backup loops allow the replay, via the substitution content provided by the security device, of the latest broadcasts broadcast by the program, thus improving the service for the user. 5.5 Simplified architecture of a security device

Finally, in connection with FIG. 5, an example of the simplified structure of a security device within a headend, implementing a security technique according to an embodiment described above, is finally presented. This Figure 5 illustrates only one particular way, among several possible, to achieve the various embodiments detailed above.

The security device 500, illustrated in FIG. 5, comprises a RAM 50, a processing unit 51, equipped for example with a processor, and controlled by a computer program stored in a ROM 52, implementing the security method according to one embodiment of the invention. At initialization, the code instructions of the computer program 52 are for example loaded into the RAM 50 before being executed by the processor of the processing unit 51. The processing unit 51 receives as input a content (Content l / Content2) generated by the main equipment or backup equipment. The processor of the processing unit 51 implements the steps of the security method described above, according to the instructions of the computer program 52, to deliver a content of the substitution (Content 3). For this, the security device comprises, in addition to the memory 50: • a monitoring module, audiovisual content generated by the main and emergency equipment, delivering a cut-off alert when a cutoff, of a duration greater than a threshold predetermined, generation by the main and backup equipment is detected; A frame encapsulation module, comprising means for receiving, from at least one of the main and backup equipment, the audiovisual content generated and means for generating a plurality of frames corresponding to the audiovisual content received; A management module, comprising means for recording, in at least one circular memory, the plurality of frames generated by the frame encapsulation module, delivering at least one backup loop, of a predetermined duration, of the audiovisual content received; • reading module, activated upon receipt of the cut-off alert issued by the monitoring module, delivering at least a portion of the audiovisual content saved for broadcast in the digital broadcast network.

These modules are driven by the processor of the processing unit 51.

Claims (9)

A method for securing the digital broadcasting of an audiovisual content in a digital broadcasting network, said audiovisual content being generated by a main equipment (10) and / or by at least one backup equipment (11) of at least a headend of said digital broadcasting network, characterized in that said method is implemented within a security device (12) of said headend and comprises: • a step of recording (20) said content audiovisual, as and when it is generated by at least one of said main (10) and back-up equipment (11), and • a supply step (21), for broadcasting in said digital broadcasting network, at least one portion (Content 3) previously recorded of said audiovisual content when a cut-off, of a duration greater than a predetermined threshold, of the generation by said main (10) and backup (11) equipment is detected e by said securing device (12). 2. A method for securing digital broadcasting of audiovisual content according to claim 1, characterized in that said recording step (20) comprises the following substeps, implemented in a frame encapsulation module ( 121) of said security device (12): • reception, from at least one of said main equipment (10) and backup (11), said audiovisual content generated; Generating a plurality of frames from said received audiovisual content; and a substep, implemented in a management module (122) of said security device (12), for recording in at least one circular memory of said security device (12) of said plurality of generated frames, delivering to the least a backup loop, of a predetermined duration, of said audiovisual content received. 3. A method of securing the digital broadcasting of audiovisual content according to claim 1, wherein said supplying step (21) is implemented until the detection of a recovery, at least a predetermined duration, the generation of said audiovisual content by said main equipment (10) and / or said backup equipment (11). 4. A method of securing digital broadcasting of audiovisual content according to claim 2, characterized in that said substep generation comprises a sub-step of enrichment of said audiovisual content received by at least one enrichment information belonging to the group comprising: a time stamping information representative of the date of reception of said audiovisual content; An information representative of the address of the source of said audiovisual content; • information representative of the destination address or addresses of said audiovisual content; An identifier for grouping a plurality of audiovisual contents 5. A method of securing digital broadcasting of audiovisual content according to any one of claims 1 to 4, characterized in that said providing step (21) comprises a substep, implemented in a monitoring module (120) of said security device (12) for monitoring said audiovisual content generated by said main equipment (10) and / or backup (11), delivering a cut-off alert when said cut is detected. 6. A method for securing digital broadcasting of audiovisual content according to claims 4 and 6, characterized in that said providing step (21) comprises the following substeps, implemented in a reading module (123). said security device (12), upon receipt of said cut-off alert issued by said monitoring module (120): • obtaining at least one backup loop; Detecting at least one enrichment information associated with at least one frame of said backup loop, and, if said detection is positive, processing said detected enrichment information delivering at least a portion of audiovisual content intended to be broadcast in said digital broadcast network. 7. Device for securing (12) digital broadcasting of audiovisual content in a digital broadcasting network, said audiovisual content being generated by a main equipment (10) and / or by at least one backup equipment (11) d at least one headend of said digital broadcast network, characterized in that said security device (12) is integrated and / or attached to at least one headend of said digital broadcasting network and comprises the following means: means for monitoring, in the form of a monitoring module (120), of said audiovisual content generated by said main (10) and back-up (11) equipment, delivering a cut-off alert when a cut, of a longer duration at a predetermined threshold, generation by said main (10) and backup (11) equipment is detected; Frame encapsulation means, in the form of a frame encapsulation module (121), comprising reception means coming from at least one of said main (10) and emergency (11) equipment said audiovisual content generated and means for generating a plurality of frames corresponding to said received audiovisual content; Management means, in the form of a management module (122), comprising means for recording, in at least one circular memory, said plurality of frames generated by said frame encapsulation module (121) , delivering at least one backup loop, of a predetermined duration, of said received audiovisual content; Reading means, in the form of a reading module (123), activated upon receipt of said cut-off alert issued by said monitoring module (120), delivering at least a portion of the audiovisual content saved for broadcast in said digital broadcast network. 8. Computer program for implementing a security method according to any one of claims 1 to 6 when the program is executed by a processor. A computer-readable and non-transitory storage medium storing a computer program comprising processor executable instructions for implementing a securing method according to any one of claims 1 to 6.