WO2010069841A2

WO2010069841A2 - Methods for broadcasting and rebroadcasting a signal in a radio broadcasting system, and corresponding broadcaster and re-broadcaster, signal, and computer software products

Info

Publication number: WO2010069841A2
Application number: PCT/EP2009/066744
Authority: WO
Inventors: David Vincent; Philippe Ganthier
Original assignee: Tdf
Priority date: 2008-12-18
Filing date: 2009-12-09
Publication date: 2010-06-24
Also published as: FR2940563B1; EP2359507B1; FR2940563A1; EP2359507A2; WO2010069841A3

Abstract

The invention relates to a method for broadcasting a digital signal from a main broadcaster (41) to at least one secondary broadcaster (42, 43) in a digital radio broadcasting network. According to the invention, the method implements the following steps at the main broadcaster (41): generating at least one marking packet corresponding to a cutaway order, a marking packet including a cutaway identifier and a piece of cutaway time information; and transmitting said at least one marking packet and said digital signal.

Description

Methods of broadcasting and re-broadcasting a signal in a corresponding radio broadcast network, broadcaster and re-broadcaster, signal and computer program products.

FIELD OF THE DISCLOSURE The field of the invention is that of the transmission and broadcasting of digital information, particularly radio data.

More specifically, the invention relates to the stalling of programs in a radio broadcast network, making it possible to switch from the broadcast of a main program by a main broadcaster of the network to the broadcasting of a secondary program by a secondary broadcaster or diffuser.

The invention applies in particular to radio data broadcast according to one of the following or future standards:

- DAB or DAB + (for "Digital Audio Broadcasting" or "Digital Broadcasting", described in ETSI EN 300 401 and ETSI TS 102 563); DMB (for "Digital Multimedia Broadcasting" or "Digital Multimedia Broadcasting", described in ETSI TS 102 428);

- DRM (for "Digital World Radio" or "World Digital Radio", described in ETSI ES 201 980);

- etc. 2. Prior Art

The problem of stalling is well known in the field of digital terrestrial television broadcasting, also known as TNT, implementing, for example, the standard

DVB-T (for "Digital Video Broadcasting - Terrestrial" or "Digital Video Broadcasting -

Terrestrial ") or DVB-H (for" Digital Video Broadcasting - Handheld "or" Digital Video Broadcast - Portable ").

In digital television, stalling makes it possible to substitute for a main program, such as a television program covered nationally on France 3 (registered trademark), a secondary program, such as a television program with regional coverage on France 3. It thus passes from a broadcast by a national transmitter broadcasting the main program, to a regional transmitter broadcasting the secondary program.

FIG. 1 illustrates an example of a television broadcasting network, comprising a main transmitter 11, also called a headend, supplying one or more secondary transmitters or re-transmitters 121, 122, 131, located at distinct geographical sites.

In certain geographical areas, these networks are of the SFN type (for "Single Frequency Network ", or isochronous, which means that the different transmitters operate at the same frequency. For example, the secondary emitters 121 and 122 belong to a first SFN plate 12, and the secondary emitter 131 belongs to a second SFN plate 13. This means that the emitters 121 and 122 of the plate 12 operate at the same frequency Fl, and the re-transmitter 131 of the plate 13 operates at another frequency F2. The re-transmitters of the same plate must be synchronized in time and frequency.

Conventionally, the headend 11 generates a main digital signal, transmitted by a network adapter and conveyed to the secondary transmitters 121, 122, 131, via a distribution network 14, for example a distribution network. satellite. Such a signal is for example of the type MPEG2-TS (in English "Motion Picture Expert Group 2 - Transport

Stream ").

One or more of the secondary transmitters 121, 122 or 131 can then unhook from the main signal by inserting a secondary program in the main signal and then broadcast the thus modified signal to receiving terminals.

Such stalling technique is described in particular in ANSI / SCTE document 35. It relies on the use of MPEG2-TS transport stream for the transport of stall commands.

Unfortunately, it is not possible to apply this solution directly to the field of radio broadcasting. Indeed, the proposed technique, which is based on a modification of the MPEG2-TS stream, is not compatible with radio broadcasting standards such as the DAB, DAB +, or DRM standard.

In addition, the adaptation of this solution to the field of radio broadcasting for the DMB standard requires modifying the PMT tables (for "Program Map Table") of the MPEG2-TS transport stream to signal the flows. containing stall commands, and to add PID packet identifiers ("packet identifier").

However, this modification of the transport stream is not desirable in radio broadcasting. Indeed, it causes a decrease in the rate during the re-broadcast of the flow of secondary transmitters to the receiving terminals, because of the addition of packets or packet identifiers. In addition, the data added to the PMT is not part of the DMB specification. It is therefore not desirable to disseminate them.

There is therefore a need for a new stall technique in the field of digital radio broadcasting, not presenting all of these disadvantages of the art. prior.

3. Presentation 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 broadcasting a digital signal from a main diffuser to at least one diffuser secondary school, also known as a broadcaster, in a digital radio broadcasting network. Such a digital signal carries at least one main program.

According to the invention, the broadcasting method implements the following steps, at the main broadcaster: generation of at least one marking packet corresponding to a stall order, a tagging packet comprising: an identifier of stall order; o stall time information, defining a time during which the secondary broadcaster can replace the main program with a secondary program in the digital signal;

transmission of the marking packet (s) and the digital signal.

The invention thus proposes a new and inventive solution of the stall in digital radio, making it possible to manage the stall on all the sites corresponding to the secondary diffusers, or re-diffusers, from the signal or transport stream transmitted by the main broadcaster. .

To do this, the invention is based on the use of specific marking packets, corresponding to stall commands, which are transmitted with the digital signal of the main diffuser to the secondary diffuser (s), in the same channel or in a channel. separate. In particular, a marking packet according to the invention carries a stall time information, defining a time during which the secondary broadcaster can insert a secondary program, for example radiophonic, into the digital signal.

For example, this stall time information comprises at least one element belonging to the group comprising:

- a moment of start of stall; - a moment of end of stall;

- stall duration;

- a request to start an immediate stall;

- a request for the end of an immediate stall.

A marking package therefore carries a kind of time stamp, which allows to indicate to broadcasters a time window during which they can "pick up" and broadcast a separate program from the main program. This time stamp is expressed from a clock of the digital transport signal, which depends on the broadcast standard used.

For example, if the broadcasting network broadcast standard is the DMB standard, the stall time information is expressed from the OCR (Object Clock Reference) conveyed in the broadcast. DMB digital signal. If the broadcasting network broadcast standard is the DAB, DAB +, or DRM standard, the stall time information is expressed from a time stamp. Other known or future radio broadcast standards may also be used within the scope of the invention.

These elements can be present in the different fields of the marking packet. For example, a marking packet comprises a field named "SpI Pos Beg" carrying a value representative of a start of stalling moment, a field named "SpI Pos End" bearing a value representative of a stall end instant, a field named "SpI Dur" bearing a value representative of a stall duration. The marking packet may also include an immediate stall start indicator, which, when read by a secondary broadcaster, forces the stall and broadcast of the secondary program, or an immediate stall indicator, which, when it is read by a secondary broadcaster, forces the return to the main program. The tagging packet also includes a stall command identifier, used by the secondary broadcasters to see whether or not to take into account the stall sequence.

According to a particular exemplary embodiment, the marking packet also comprises a field called "Flags" including in particular the following indicators:

an indicator of the presence of an element of instant start-of-stall type, named for example "Beg";

an indicator of the presence of an element of the instant end-of-stall type, named for example "End";

an indicator of the presence of an element of the stall duration type, named for example "hard"; the request indicator for immediate start of stall, forcing a switch to a secondary program, named for example "End";

- the indicator of immediate end of stall request, forcing a return on the main program, named for example "Fout";

an indicator erasing the previously stored stall commands for a given stall order identifier, named for example "Rst". According to a first embodiment, the marking packet or packets are inserted into the digital signal prior to the transmission step.

In other words, a stall sequence can be transmitted directly into the digital stream, using the transport layer DCP (for "Distribution and Communication Protocol", for example). This transmission is described as "in-band" or "in-band" transmission. It makes it possible, in particular, to preserve the existing structure of the digital stream, and to ensure compatibility with the re-diffusers adapted to manage a stall or not. According to a second embodiment, the marking packet or packets are transmitted to the secondary diffusers via a means of transmission distinct from the digital signal.

A stall sequence can thus be transmitted via a separate link, using an Internet protocol (IP or "Internet Protocol") for example. This transmission is described as "out-band" or "out-of-band" transmission.

According to one particular aspect of the invention, the digital signal is transmitted according to the DCP distribution and communication protocol, as defined in ETSI standard TS 102 358 for example.

It is noted that such a protocol operates, in a conventional manner, with an EDI type overlay used for the DMB, DAB or DAB + broadcast standards, or of the Multiplex Distribution Interface (MDI) type, such as described in ETSI ETS 300 799) for the DRM broadcast standard.

According to a particular characteristic of the invention, the broadcasting method comprises a step of receiving a stall command insertion request, prior to the step of generating at least one marking packet.

This insertion request can be triggered by an external event, such as sending a command or filing a file, or triggered automatically, taking into account an external clock for example.

In particular, the insertion request may carry a timestamp information, expressed taking into account an external synchronization source. The broadcasting method then comprises a step of converting the timestamp information into a stall time information, expressed taking into account a digital signal clock.

In other words, if the moment at which the stall must occur is previously known, but is not expressed in the same time base as that of the digital signal, it is necessary to convert that moment into the timebase of the digital signal. It is this new information, expressed taking into account the clock of the digital signal, which will be transmitted to the different re-diffusers in the marking packet or packets.

In another aspect, the same tagging packet is transmitted periodically. In this way, the non-stall problems that may occur during the loss of a marking packet are avoided. This periodic transmission is interrupted once the stall time has passed.

The invention also relates to a computer program product downloadable from a communication network and / or recorded on a computer readable medium and / or executable by a processor, comprising program code instructions for implementing the method of broadcast as described above.

In another embodiment, the invention relates to a main broadcaster broadcasting a digital signal to at least one secondary broadcaster, in a digital radio broadcast network, said digital signal carrying at least one main program.

According to the invention, the main diffuser comprises:

means for generating at least one marking packet as defined above;

means for transmitting the marking packet or packets and the digital signal. Such a main diffuser is particularly suitable for implementing the broadcasting method described above. This is for example a device for encoding and multiplexing radio data.

Another aspect of the invention relates to a signal broadcast by a main broadcaster to at least one secondary broadcaster, or re-broadcaster, in a digital radio broadcast network, carrying at least one marking packet as defined above.

Such a signal is for example broadcast by a main diffuser as described above. It may of course include the various characteristics relating to the diffusion method according to the invention. Thus, in the context of an "out-band" transmission, this signal carries only stall commands, in the form of marking packets. As part of a transmission

In-band, this signal carries at least one main radio program in addition to one or more tagging packets.

The invention also relates to a method for re-broadcasting a modified signal, in a digital radio broadcasting network comprising a main diffuser supplying at least one secondary diffuser, or re-diffuser.

According to the invention, such a method implements the following steps, at at least one of the secondary diffusers: reception of a digital signal carrying at least one main program and at least one marking packet as defined previously;

- reading the marking package;

checking the stall order identifier, and according to the result: determining a stall start time, based on the stall time information; o replacement of the main program by the secondary program in the digital signal received, from the start of stalling, delivering a modified signal; o broadcast of the modified signal. The reading of the marking packet thus enables a re-diffuser to determine whether to perform the stall, taking into account the stall order identifier, and when it must perform this stall, taking into account the stall stall time information.

The stalling order can therefore be previously received by the re-diffuser, but the stall is performed only when the clock of the received digital signal actually reaches the stall time.

Thus, the step of determining a stall start time implements a comparison between the stall time information and a clock of said received digital signal. As indicated above, according to a first embodiment, the marking packet or packets are inserted into the digital signal prior to transmission. The digital signal received then carries at least one main program and at least one marking packet as defined above.

According to a second embodiment, the marking packet or packets are transmitted to the secondary diffusers via a means of transmission distinct from the digital signal. The reception step thus makes it possible to receive a first digital signal carrying at least one main program and a second signal carrying at least one marking packet.

According to another aspect of the invention, the re-diffusion method comprises a step preliminary reception of the secondary program and storage in a memory.

The secondary program can notably be received in real time and stored in a buffer memory.

The invention also relates to a computer program product downloadable from a communication network and / or recorded on a computer readable medium and / or executable by a processor, comprising program code instructions for implementing the method of re-broadcast previously described.

Another embodiment of the invention relates to a secondary diffuser of a modified signal, in a digital radio broadcasting network comprising a main diffuser supplying at least one secondary diffuser, comprising:

means for receiving a digital signal carrying at least one main program and at least one marking packet as described above:

reading means of the marking packet;

means for verifying the stall order identifier; means for determining a start-of-stall time, from the stall time information;

means for replacing the main program by the secondary program in the digital signal received, from the moment of stall initiation, delivering a modified signal; means for broadcasting the modified signal.

Such secondary diffuser is particularly adapted to implement the replay method described above. This is for example a local encoder or relay, allowing local stalls.

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 example of a television broadcasting network according to the prior art; FIG. 2 presents the main steps of the diffusion method according to one embodiment of the invention; FIG. 3 presents the main steps of the re-diffusion method according to one embodiment of the invention; FIG. 4 illustrates an exemplary radio broadcast network according to one embodiment of the invention; Figure 5 shows the structure of a main diffuser according to one embodiment of the invention; Figure 6 shows the structure of a secondary diffuser according to one embodiment of the invention; FIGS. 7A to 7D illustrate an exemplary structure of a marking packet according to different broadcasting standards.

5. Description of an embodiment of the invention

5.1 General principle

The general principle of the invention is based on the transmission of specific packets, called tagging packets, from a main broadcaster to at least one secondary broadcaster, also called a re-broadcaster, in a digital radio broadcasting network, making it possible to indicate the secondary broadcaster a time range during which it can "drop out" of a main program and broadcast a secondary program, such as a local radio program.

In this way, it is possible to manage the stall on different secondary diffusers of the broadcast network from the digital signal broadcast by the main broadcaster, carrying at least one main program. In addition, the stall configuration of the different secondary diffusers is independent. Each secondary diffuser can thus insert into the broadcast signal a program of its own, in the time range thus identified. In other words, the secondary program replacing the main program during the stall can be a video, a BIFS scene, an audio program, a radio program, etc.

The term "unhooking" here refers to the detachment of one or more re-broadcasters from the broadcasting network to allow the broadcast of local programming. For example, the main program corresponds to the national information, and the program secondary to the regional information, specific to a specific geographical area. It should be noted that the invention can be applied regardless of the radio broadcast standard used, such as the DAB, DAB +, DRM, or DMB standard, or a future standard.

Figure 2 illustrates more precisely the main steps implemented at the main diffuser, for the transmission of a digital signal from the main diffuser to the secondary diffuser or diffusers, according to one embodiment of the invention. During a first step 21, the main diffuser generates at least one marking packet corresponding to a stall order. Such a marking package comprises at least:

- a stall order identifier;

- stall time information, defining a time during which a secondary broadcaster can insert a secondary program, for example a radio program, into the main digital signal.

During a next step 22, the main broadcaster transmits the marking packet or packets as well as the digital signal comprising at least one main program for the secondary diffuser or diffusers. This or these packets may be inserted into the digital signal or transmitted via another transmission means.

The main steps implemented by a secondary distributor are illustrated in Figure 3.

During a first step 31, the digital signal and one or more marking packets as defined above are received by a secondary diffuser.

The secondary diffuser then reads a marking packet during a second step 32, and verifies the stall order identifier during a third step 33.

If the identifier is valid, the secondary broadcaster determines (34) a stall start time, from the stall time information, and replaces (35) the main program with a secondary program, in the digital signal, at the moment of start of stall, delivering a modified signal. For example, this secondary program is a regional program, replacing a national program transmitted in the digital signal.

Finally, the signal thus modified is broadcast (35) to digital receivers, such as mobile phones, car radios, personal digital assistants, set top boxes, etc. 5.2 Description of an embodiment A) Broadcast network equipment

An embodiment of the invention is described below in a digital radio broadcasting network comprising a main diffuser and two secondary diffusers or re-diffusers, as illustrated in FIG. 4.

According to this example, the main broadcaster 41 includes a specific module 411, making it possible to generate and send orders or "splice" requests (in English "splice") to at least two secondary diffusers 42 and 43.

This stall command generation module 411 takes into account the digital signal, comprising at least one main program, intended to be broadcast by the main broadcaster. This transport signal is still called DMB stream, DAB stream, DRM stream, etc., depending on the broadcast standard used. It is considered hereinafter that this digital signal is transmitted using the DCP transport layer, and this signal "DCP signal" or "DCP flux" is noted, whatever the broadcast standard used. Of course, this notation is not limiting, and the signal digital can be transported according to other protocols.

The stall command generating module 411 makes it possible to construct a stall sequence by generating a marking packet comprising at least:

- a stall order identifier; - Stall time information, to define the stall position in the DCP signal received by a re-diffuser.

In other words, a stall sequence contains sufficient data to allow a secondary broadcaster to determine a stalling point or moment in the digital signal broadcast by the main broadcaster. This stall command generating module 411, or the main broadcaster 41 to which it belongs, can then send the stall commands to the secondary broadcasters.

According to an advantageous embodiment, this transmission is a transmission "in- band" (in the band), illustrated by the arrow 44 in solid lines. This transmission relies on the insertion of the marking packets directly into the DCP signal, before the DCP is broadcast by the main broadcaster.

According to one variant, the transmission is an "out-band" transmission, illustrated by the arrow 45 in full dashed line. This transmission is based on the sending of the marking packets in a signal distinct from the DCP signal broadcast by the main broadcaster.

The secondary diffusers 42, 43 thus receive the DCP signal and the marking packet or packets transmitted in the same channel or in separate channels.

According to the example described, the secondary diffuser 42 (respectively 43) comprises a stall module 421 (respectively 431), capable of receiving and executing received stall commands. This stall module 421 makes it possible to replace a main program of the DCP signal with a secondary program, in order to deliver an off-hook program. For example, the stall module 421 implements the following steps:

- receipt of stalling orders ("in-band" or "out-band");

- verification and filtering of stall orders;

- interpretation of stall orders;

- management of the sources used to perform the content modification; - DCP flow analysis;

- achievement of the stall.

It is noted that the methods according to the invention can be implemented in various ways, in particular in hard-wired form or in software form. These different devices communicate in particular by using the IP protocol. B) Operation of the stall command generation module Hereinafter described in greater detail, with reference to FIG. 5, an example of operation of the main diffuser 41.

According to this example, the main broadcaster 41 receives as input sources to encode 51 (digital radio program, audio, video, multimedia file, etc.), which are coded by a coder 412. The main broadcaster 41 also receives input requests. stall command insertion 52, and optionally synchronization information 53, from an external synchronization source (for example from NTP, for "Network Time Protocol" or networked time protocol). The main diffuser 41 outputs a digital signal formatted in a DCP encapsulator 413, also called DCP stream, as well as marking packets, including stall commands. The stall commands can be inserted into the DCP stream 44 or sent by an ancillary channel 45 (using an internet protocol on an IP channel for example). More specifically, the generation of an off-hook command is implemented in the stall command generation module 41 1, upon receipt of a stall command insertion request 52. This request may be caused by an external intervention, such as sending an order via IP, filing a file in FTP ("File Transport Protocol" or file transfer protocol), etc, or triggered automatically, taking into account, for example, a clock. In the latter case, the stall command insertion request 52 must be time stamped.

The stall command generation module 411 uses one or more synchronization sources to determine the stall position in the DCP stream, i.e., to determine the stall time information defining a time in which a secondary broadcaster can insert a secondary program into the DCP stream.

More precisely, the stall command generating module 411 takes as input synchronization information 54 with respect to the digital signal generated by the encoder 52, determined taking into account the clock of the transport signal. The stall time information transmitted to a re-diffuser in a marking packet is therefore determined taking into account the time base of the transport signal. For example, it is an OCR value indicating the start time and the end time of the stall for a broadcast according to the DMB standard, or an EDI time stamp value for a broadcast according to the DAB or DAB + standards, and MDI for distribution according to the DRM standard.

The stall command generating module 411 can also take into account the synchronization information 53 from an external source (NTP for example). This synchronization information 53 is used by the module 411 to synchronize the stall command insertion request 52, when it is time stamped. In this case, the stalling orders are dated, that is to say the determination of the stall time information, by comparing the synchronization information 54 from the digital signal and the synchronization information 53 from the digital signal. an external source. This comparison makes it possible to convert the time stamp of the stall command insertion request 52 to the time base used in the DAB, DAB +, DRM or DMB transport signal. The stall command generation module 411 thus makes it possible to generate one or more marking packs 55, each packet corresponding to a stall order to be transmitted to the secondary broadcasters.

According to this exemplary embodiment, a marking packet comprises at least:

a field carrying a unique identifier of stalling order, named "SpI Ord ID" for example, allowing the stall module 421 to know whether the stalling order is to be taken into account or not. The value of this field is configurable;

at least one field carrying a stall time information, making it possible to identify the position of the stall point, or "splice" point, in the DCP signal (value of the OCR for the DMB standard or of a time stamp) for the DAB standard for example). For example, this time information specifies the start date (value of the OCR equal to Vl) and the end date (value of the OCR equal to V2) of the stall.

Optionally, the marking packet also includes a field carrying a stall duration. This field defines a duration before returning to the main program, that is to say a duration during which the secondary broadcaster can broadcast a secondary program before returning to the broadcast of the main program.

The structure of the marking packs according to this embodiment of the invention will be described in more detail below, in connection with FIGS. 7A to 7D.

In order to prevent the losses of a stall sequence during transport between the main diffuser 41 and the secondary diffusers 42 or 43, a marking packet corresponding to a stall sequence can be repeated several times before the stall point. According to a variant embodiment, once the stall start date has passed, the main broadcaster 41 can periodically send commands to the secondary diffusers 42 or 43 to force the stall. For example, according to the DMB standard, if the time information associated with a stall order specifies a stall start date corresponding to an OCR value equal to Vl, the marking packet can be transmitted more than once until the OCR value of the transport signal is lower (earlier) than Vl. Once this value has passed, the main broadcaster can send, possibly periodically, an order to force the stall, for example by assigning a specific value ("1"). ) an Immediate Start Request Indicator ("End").

C) Transportation of the stall order

As indicated above, the transport of the marking packet or packets to the secondary broadcasters carrying out the stall ("splicer" in English) can be done "in-band", that is to say in the digital signal, by using the transport layer DCP for example, and / or

"Out-band", by sending the marking packet (s) on a separate link, via an IP type link for example.

For an "in-band" transmission, as illustrated by the solid line arrow 44 in FIG. 4, the stalling order may be conveyed by a proprietary DCP tagging tag. This can be inserted into the DCP stream according to the broadcast standard.

The use of the DCP transport layer for the transport of the stall commands avoids modifying the structure of the digital stream that will be transmitted. Moreover, the use of this mode of transport makes it possible to maintain the compatibility with the equipment not managing the stalling commands, since the DCP marking packets or "tag" not recognized by a device are automatically ignored.

For an "out-band" transmission, as illustrated by the dashed arrow 45 in FIG. 4, the stall sequence may be carried outside the DCP stream and may be transported over an IP link using the UDP protocol. For example, a "User Datagram Protocol" or a TCP ("Transport Control Protocol"). In order to homogenize the formats of the stall sequences, the "out-band" transmitted tag packets advantageously have the same structure as the "in-band" tagging packets.

According to a particular embodiment of the invention, to ensure a significant flexibility of the stall, the tagging packets conveyed "in-band" or "out-band" include only:

- A stall order identifier, which may be used by the secondary diffuser to decide whether to take into account the stall sequence;

an identification in the flow of the stall time range, in the form temporal information of stall.

Advantageously, the very configuration of the stalls, that is to say the choice of streams to pick up (audio, video, BIFS ...), can be parametered separately on each secondary diffuser that achieves the stall. Thus, the different secondary diffusers 42 and 43 can achieve a stall of different type on receipt of the same stall order. D) Operation of the equipment performing the stall

Hereinafter described in greater detail, in connection with FIG. 6, an example of operation of the secondary diffuser 42 or 43.

Such a secondary diffuser receives as input the DCP stream, as well as one or more tagging packets. These tagging packets may be received in the DCP stream 44 (in-band transmission) or in a separate stream 45 (out-band transmission).

The equipment performing the stall includes several modules. A stall command extraction module 61 receives the DCP stream 44 as input. It extracts from this stream the marking packets corresponding to the stall commands, in the case of an "in-band" transmission. The tagging packets thus extracted are transmitted to a stall command management module 62.

The stall command management module 62 may receive stall commands from the stall command retrieval module 61, in the case of an "in-band" transmission, or may directly receive stall commands, on an IP 45 connection for example, in the case of an "out-band" transmission. The stall command management module 62 then checks whether the stall must be taken into account, by checking the stall order identifier. If the order is valid, the module 62 searches for the local stall configuration associated with it (audio, video, BIFS, etc.), by consulting a stall configuration base 63. If the stall order received does not match is not valid, it is ignored. Here is meant by valid order (or identifier) an order which has for identifier an identifier present in the base of stall configuration 63 of the secondary diffuser.

The stall command management module 62 then transmits to the stall module 64 the commands and the configuration of the valid stall commands. These commands make it possible to indicate to the stall module 64 the stalling moment, in the form of the identifier of the corresponding packet (PID to be picked up, identified from the value VI of the OCR for example, for the DMB). the source to use for stall, etc.

This known information, the module 64 derailment scans the DCP stream in search of a stall point to take into account. When the module 64 detects a stall point, it performs the stall in accordance with the configuration associated with it, in replacing a main program of the DCP stream with a secondary program, and broadcasting the stream thus modified 67, according to the DCP protocol for example.

The secondary source (s) providing secondary content used for the stall can be of different natures. For example, a source can provide a real-time secondary program to broadcast. This program comes for example from a secondary stream, transmitted according to the DCP protocol for example. According to one variant, this program comes from an analog source and is encoded in an encoder 65. In these two cases, the stall module comprises a buffer memory 641 in which the secondary program is stored until it receives the stall point. . The use of this buffer 641 makes it possible to re-synchronize the beginning of the secondary program with the insertion point in the main stream.

Other contents such as pre-recorded contents and stored in a memory 66, in the form of files for example, can also be used as a secondary source.

E) Structure of the marking packets With reference to FIGS. 7A to 7D, the structure of the marking packs according to a particular embodiment of the invention will now be described.

As already indicated, a marking packet corresponds to a stall order, and includes sufficient data to allow the secondary diffuser to identify the stall point in the DCP stream. Fig. 7A illustrates an exemplary structure of a tagging packet according to this embodiment.

According to this example, the marking package comprises:

a 32-bit field, named "tag name" 71, derived from the DCP standard, and making it possible to identify the tagging packet; a 32-bit field, named "Tag length" 72, derived from the DCP standard, and giving the length of the bit marking packet;

a 32-bit field, named "SpI ord ID" 73, containing the unique stall command identifier on the network;

an 8-bit field, called Flags 74, comprising eight indicators; a field of N bits (N integer), named "SpI Pos Beg" 75, containing the information necessary for identifying the stall start point in the DCP stream. The format of this field is related to the content to be picked up according to the broadcast standard used (eg DMB, DAB, DAB + or DRM);

a field of N bits (N integer), named "SpI Pos End" 76, containing the information necessary to identify the end-of-stall point in the DCP stream. The format of this field will be related to the content to be dropped according to the broadcast standard used (eg DMB, DAB, DAB + or DRM);

an optional field of M bits (M integer), named "SpI Dur" 77, containing the duration of the stall. The format of this field will be related to the content to be picked up according to the broadcast standard used (eg DMB, DAB, DAB + or DRM). The eight bits of the flags field 74 include:

an indicator called "Beg" 741 which, if it is at 1, indicates a start-of-stall order. The stall start position is then in the "SpI pos Beg" field. The field "SpI pos Beg" must be present if this indicator is used;

an indicator called "End" 742 which, if it is at 1, indicates the end-of-stall order. The position of the end of stall is then in the field "SpI pos End". The "SpI pos End" field must be present if this indicator is used;

an indicator called "hard" 743 which, if it is at 1, indicates the presence of the "Hard SpI" field used to give the duration of the stall sequence identified by the identifier

"SpI ord ID";

an immediate stall start request flag named "End" 744 which, if it is at 1, forces the switch to the secondary program;

- an end of stall request indicator called "Fout" 745 which, if it is at 1, forces the return to the main program;

an "Rst" indicator 746 which, if it is at 1, erases all previously stored stall commands for the identifier "SpI ord ID";

two bits named "Rfu" 747, 748 not used.

FIG. 7B illustrates an exemplary terrestrial DMB (or T-DMB) broadcast tag package. According to this example:

the "tag name" field 71 can take the value ADMB, or any other value making it possible to identify this marking packet;

the "Tag length" field 72 can take the values 40, 80, 120 or 160;

the "SpI Pos Beg" field 75 is used to indicate the position of the stall start point in the DCP stream. It comprises for example 40 bits (N = 40). The 40 bits use the same time base as the DCR of the DCP stream. The 7 most significant bits therefore represent the number of complete cycles of OCR needed before the time stamp (or "time stamp") of the 33 low-order bits can be taken into account to find the start point of the stall; the "SpI Pos End" field 76 is used to indicate the position of the stall end point in the DCP stream. It also includes 40 bits (N = 40). The 40 bits use the same time base as the DCR of the DCP stream. The 7 most significant bits therefore represent the number of complete cycles of OCR needed before the time stamp of the 33 low-order bits can be taken into account to find the end-of-stall point;

the "SpI-Dur" field 77 contains the duration of the stall before returning to the DCP stream. It comprises for example 40 bits (M = 40). The duration is therefore coded on 40 bits and uses the same time base as the OCR of the DCP stream. Thus, for broadcasting according to the T-DMB standard, the identification of the stall point can be performed by comparing the value of the OCR of the DCP stream with the value of the "SpI Pos Beg" field of the marking packet.

Figure 7C illustrates an example of a broadcast tagged package according to the DRM standard. According to this example: the "tag name" field 71 can take the value ADRM, or any other value making it possible to identify this marking packet;

the "Tag length" field 72 may take the values 40, 96, 128 or 152;

the "SpI Pos Beg" field 75 comprises, for example, 56 bits (N = 56). The 50 least significant bits are used to carry the time stamp used in the tist marker of the MDI interface to transport the DCP stream to DRM. This marker is well known to those skilled in the art, and in particular described in the document ETSI TS 102 820 supra. The value carried by this field corresponds to the stall start point;

the "SpI Pos End" field 76 also includes 56 bits. The 50 least significant bits are used to carry the time stamp used in the MDI tist marker to carry the DCP stream in DRM. The value carried by this field corresponds to the end of stall point;

the "SpI-Hard" field 77 comprises, for example, 32 bits (M = 32). It gives the stall duration in milliseconds since the start of the stall. FIG. 7D finally illustrates an exemplary broadcast tag broadcast according to the DAB or DAB + standard. According to this example:

the "tag name" field 71 can take the value ADAB, or any other value making it possible to identify this marking packet;

the "Tag length" field 72 can take the values 40, 104, 136, 168; the "SpI Pos Beg" field 75 comprises, for example, 64 bits (N = 64). It carries a time stamp to identify the position of the start point of stall in the DCP stream. The time stamp format is that of the EDI protocol used for transporting DAB, DAB + or DMB over IP using the DCP standard. According to this protocol, the "SpI Pos Beg" field 75 is decomposed by the two fields named "seconds" and "TIST". The two fields are concatenated as follows: o the "second" field on 32 bits, gives the number of seconds since ^January 1, 2000 00:00:00; o the "TIST" field, on the 32 low-order bits, gives the reference in the second. The format of this field is defined in Annex B of ETSI EN 300 797;

the "SpI Pos End" field 76 also includes 64 bits (N = 64). It contains a time stamp to identify the position of the stall end point in the DCP stream. The format of the time stamp is that of the EDI protocol, as described above;

the "SpI-Hard" field 77 comprises, for example, 32 bits (M = 32). It gives the stall duration in milliseconds since the start of the stall.

Claims

A method of broadcasting a digital signal from a main broadcaster (41) to at least one secondary broadcaster (42), or re-broadcaster, in a digital radio broadcast network, said digital signal carrying at least one a main program, characterized in that said method implements the following steps, at said main diffuser (41):

generating (21) at least one marking packet corresponding to a stall order, a marking packet comprising: a stall command identifier; o stall time information, defining a time during which said secondary diffuser can replace said main program by a secondary program in said digital signal;

transmission (22) of said at least one marking packet and said digital signal, said stall time information comprising at least one element belonging to the group comprising:

- a moment of start of stall;

- a moment of end of stall;

- stall duration; - a request to start an immediate stall;

an immediate stall completion request, said start and / or end stall times being expressed from a clock of said digital signal.

2. Broadcast method according to claim 1, characterized in that said at least one marking packet is inserted into said digital signal prior to said transmission step.

3. Broadcasting method according to any one of claims 1 and 2, characterized in that said at least one marking packet is transmitted to said secondary diffusers via a transmission means separate from said digital signal.

4. Broadcasting method according to any one of claims 1 to 3, characterized in that said digital signal is transmitted according to the distribution protocol and DCP communication.

5. Broadcasting method according to any one of claims 1 to 4, characterized in that it comprises a step of receiving a stall order insertion request, prior to said generation step of at least a marking package.

6. Broadcasting method according to claim 5, characterized in that said insertion request carries a time stamping information, expressed taking into account an external synchronization source, and in that said method comprises a step of converting said timestamp information, in said stall time information, expressed taking into account a clock of said digital signal.

7. Broadcasting method according to any one of claims 1 to 6, characterized in that said marking packet comprises the following indicators:

an indicator of the presence of an element of type instant start of stall;

an indicator of the presence of an element of the instant end-of-stall type; an indicator of the presence of an element of stall duration type;

- a request indicator of immediate start of stall;

an indicator of the request of the end of an immediate stall, forcing a return on the main program;

an indicator erasing previously stored stall commands for a given stall command identifier.

8. Broadcasting method according to any one of claims 1 to 7, characterized in that said marking packet is transmitted periodically.

9. Computer program product downloadable from a communication network and / or recorded on a computer readable medium and / or executable by a processor, characterized in that it comprises program code instructions for the implementation of the diffusion process according to at least one of claims 1 to 8.

10. Main broadcaster (41) broadcasting a digital signal to at least one secondary broadcaster (42, 43) in a digital radio broadcast network, said digital signal carrying at least one main program, characterized in that said broadcaster principal (41) includes:

means for generating (411) at least one marking packet corresponding to a stall order, a marking packet comprising: a stall command identifier; o stall time information, defining a time during which said secondary diffuser can replace said main program by a secondary program in said digital signal;

means for transmitting said at least one marking packet and said digital signal, said stall time information comprising at least one element belonging to the group comprising:

- a moment of start of stall;

- a moment of end of stall;

- stall duration; - a request to start an immediate stall;

11. Signal broadcast by a main broadcaster (41) to at least one secondary broadcaster (42, 43), or re-broadcaster, in a digital radio broadcast network, characterized in that it carries at least one packet marking marking corresponding to a stall order, a marking packet comprising: o a stall order identifier; o stall time information, defining a time during which said secondary diffuser can replace a main program by a secondary program in a digital signal, said stall time information comprising at least one element belonging to the group comprising: - a start time stall;

- a moment of end of stall;

- stall duration;

- a request to start an immediate stall;

12. A method for re-broadcasting a modified signal in a digital radio broadcasting network comprising a main diffuser (42) supplying at least one secondary diffuser (43), or re-diffuser, characterized in that it the following steps, at least one of said secondary diffusers:

receiving (31) a digital signal, carrying at least one main program, and at least one marking packet, said marking packet corresponding to an off-hook command and comprising: o a stall order identifier; o stall time information, defining a time during which said secondary diffuser can replace said main program by a secondary program in said digital signal; reading (32) said marking packet;

- checking (33) of said stall order identifier, and according to the result: o determining (34) a stall start time, from said stall time information, implementing a comparison between said time information stall and a clock of said received digital signal; o replacing (35) said main program by said secondary program in said received digital signal, from said stall start time, delivering a modified signal; o broadcasting said modified signal.

13. Re-broadcasting method according to 12, characterized in that it comprises a prior step of receiving said secondary program and storage in a memory.

14. Computer program product downloadable from a communication network and / or recorded on a computer readable medium and / or executable by a processor, characterized in that it comprises program code instructions for the implementation of the re-diffusion method according to at least one of claims 12 and 13.

15. Secondary diffuser (42, 43) of a modified signal, in a digital radio broadcasting network comprising a main diffuser (41) supplying at least one secondary diffuser, characterized in that it comprises: - reception means of a digital signal carrying at least one main program and at least one marking packet, said marking packet corresponding to a stall sequence and comprising: a stall command identifier; o stall time information, defining a time during which said secondary diffuser can replace said main program by a secondary program in said digital signal;

means for reading said marking packet;

means for verifying said stall order identifier;

means for determining a start-of-stall time, from said temporal stall information, implementing means of comparison between said stall time information and a clock of said received digital signal;

means for replacing said main program by said secondary program in said received digital signal, from said start-of-stall time, delivering a modified signal;

means for broadcasting said modified signal.