FR2985628A1 - Device for reception of multiplexed stream of successive packets of information, has determination unit determining contents of program map table, and reception unit using data included in listing descriptor - Google Patents

Abstract

The device has a program map table (132) that contains a list of elementary flows of audio and/or visual service in a diffusion course, where the audio and/or visual services are intended to be reproduced in real-time. A determination unit is utilized for determining contents of the program map table, and for determining a listing descriptor of program identifiers of the list of elementary flows that includes a secondary flow. The secondary flow forwards unconstrained audio-visual temporal document. A reception unit uses data included in the listing descriptor. Independent claims are also included for the following: (1) a method for generation of a multiplexed stream of successive packets of information (2) a device for generation of a multiplexed stream of information (3) a downloadable computer program product comprising instructions for performing a method for generation of the multiplexed stream of information.

Description

Device for receiving a multiplexed stream broadcasting a PMT table including a descriptor for identifying documents transmitted in PUSH mode, and apparatuses associated with the method. FIELD OF THE INVENTION The invention relates to a method of generating an organized flow in successive data packets, a method of receiving said stream and apparatuses for implementing the method. The present invention relates to the field of broadcasting audiovisual documents on digital communication networks. Audiovisual means any type of multimedia content such as video, audio, data. The present invention relates more particularly to a method for transmitting audiovisual document flows transmitted in "PUSH" mode. 2. Prior art Nowadays, there are many ways to achieve the transmission of digital content, among which the techniques based on the standards resulting from DVB consortia ("Digital Video Broadcast" for "Digital Video Broadcasting"). ). Other content transmission techniques are also used with networks operating using the IP protocol (from the English "Internet Protocol" for "Internet Protocol"). These contents are transmitted using a material medium (a cable for example) or intangible (a wireless network, usually radio). Special "Video On Demand" services allow users to download audiovisual documents. For this purpose, the user's terminal connects to a download site, receives the catalog of available documents and displays it on the screen. The user navigates the menu, selects a content and orders its download. When the document is intended to be stored in the terminal, its download is not constrained by time. The download can for example be done at night. The next day, the user has his document and can reproduce, the download time does not affect its reproduction. More particularly in the remainder of this document to describe an existing problem in the field of digital television broadcasting networks, which faced the inventors of the present patent application. The invention is not limited, of course, to this particular field of application, but is of interest for any information transmission or dissemination technique that has to deal with a similar or similar problem.

Digital television broadcasting networks, such as TNT networks, implementing the DVB-T standard ("Digital Video Broadcasting - Terrestrial" for "digital terrestrial video broadcasting"), are now deployed in France, in Europe, and in several other states of the world. Broadcasting of data packets is specified by standards so as to be received by a large number of receivers of any type. The network (terrestrial, satellite or cable) broadcasts audiovisual documents in data streams more commonly known as "services" and data intended to reference them. These data are for example defined in the DVB-SI specifications (Digital Video Broadcast - specification for Service Information) or still 'digital video broadcasting - specification of Service Data' EN 300 468 V1.3.1 (published by ETSI) and the standard "Information technology - Generic coding of moving pictures and associated sound: System", referenced MPEG ISO / IEC 13818-1, 2nd edition published on December 1, 2000. This service information is in the form of tables and descriptors that describe the objects transmitted on the transmission network. The documents broadcast according to the standard are viewed in real time by the receiver. Therefore, a problem arises when the network transmits both real-time documents and documents to be downloaded without being reproduced by the receiver in real time. These can not be presented in a program selection menu since their reproduction in real time is impossible. 3. Objectives of the invention The present invention provides a solution that does not have the drawbacks described above, while providing the advantages listed above. The proposed solution makes it possible to quickly determine in the stream defined by the DVB standard the services diffusing documents in real time and documents transmitted without temporal constraints. These are intended to be registered as soon as they are received, and reproduced later, once they have been received in full. 4. DISCLOSURE OF THE INVENTION The present invention proposes a device for receiving a multiplexed stream specified by the DVB-SI standard and organized in successive data packets comprising at least one main stream comprising a first PAT table identifying at least a first PMT table containing at least the list of elementary streams of an audio and / or visual service being broadcast and intended to be reproduced in real time. The device comprises means for determining in the content of said first PMT table a descriptor listing identifiers (or PID) of elementary streams constituting a secondary stream, said secondary stream transmitting at least one audiovisual document without time constraint. The device receives the audiovisual document using the data included in the descriptor transmitted in the stream.

In this way, it is easy to distinguish the services transmitted in real time and present in the main stream, and the documents transmitted without temporal constraints because intended for the recording and identified in the descriptor. The invention proposes, according to a particular embodiment, that the first identifier of said descriptor is an identifier of a second PAT table identifying a second PMT table, the second PMT table contains at least the list of elementary stream identifiers transmitting said document. audio-visual. In this way, the structure relies on the DVB standard to identify documents transmitted without time constraints. The invention also relates to a method for generating a multiplexed stream specified by the DVB-SI standard and organized into successive data packets comprising at least one main stream comprising a first PAT table identifying at least a first PMT table containing at least the list of elementary streams of an audio and / or visual service being broadcast and intended to be reproduced in real time. The method includes a step of inserting into said first PMT table of the main stream of a descriptor listing elementary stream identifiers constituting a secondary stream, said secondary stream transmitting at least one audiovisual document without time constraint. According to a particular embodiment, the number of the identifier of the first table PAT is 0, the number of the identifier of the second table PAT is different from 0. In this way, it is easy. to distinguish the PAT table describing the main flow of the PAT table which identifies the documents transmitted without temporal constraints. According to another embodiment, time indications determine the beginning and / or end of the transmission of the secondary stream transmitting said audiovisual document are inserted in the multiplexed stream. In this way, the receiving terminal can easily program the recording of the audiovisual document. According to another embodiment, temporal indications determining the beginning and / or the end of the validity of said audiovisual document. In this way, it is possible to control the availability of the document within a receiver. According to another embodiment, a priority indication for defining the deletion order of audiovisual documents recorded in a receiver when there is not enough room to store a new document is inserted in the multiplexed stream. . In this way, it is possible to remotely manage the occupancy of the memory of the receivers. According to another embodiment, an indicator can take at least one of the values signaling the following states: start of transmission of an audiovisual document during a determined duration, transmission of an audiovisual document in progress, stop no definitive transmission of an audiovisual document, is inserted into the multiplexed stream. In this way, it is possible to inform the receivers of the current state of transmission of the audiovisual document.

According to a hardware aspect, the invention relates to a device for generating a multiplexed stream specified by the DVB-SI standard and organized in successive data packets comprising at least one main stream comprising a first PAT table identifying at least a first PMT table. containing at least the list of elementary streams of an audio and / or visual service being broadcast and intended to be reproduced in real time. The device comprises means for inserting into the content of said first PMT table of the main stream of a descriptor listing elementary stream identifiers constituting a secondary stream, said secondary stream transmitting at least one audiovisual document without time constraint. The invention also relates to a computer program product comprising program instructions for executing the method of generating a multiplexed stream. 5. 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 nonlimiting example, and the accompanying drawings, among which: FIG. 1 illustrates the tree of stream identifiers (PID) defined by the DVB standard for the implementation of the invention according to a first exemplary embodiment; FIG. 2 represents a table descriptor PMT describing a example of a structure for the transmission of audiovisual documents without temporal constraint, - figure 3 represents a part of an EIT descriptor describing additional data for the transmission and recording of audiovisual documents, - figure 4 describes an example of server for the generation of multiplexed streams, - Figure 5 describes an example of audiovisual receiver for receiving multiplexed streams, - FIG. 6 presents a timing diagram of the transmission of the EIT tables and the succession of the transmission states, according to an exemplary embodiment. 6. DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 6.1 GENERAL PRINCIPLE The invention lies in the context of the transmission and reception of audio and / or visual contents in "PUSH" mode. The "PUSH" mode means that the document is transmitted without the temporal constraints allowing its reproduction in real time upon its reception. A document transmitted in PUSH mode is first stored in the receiver's memory, then following a command from the user, it is reproduced by extracting the data from the memory. The invention proposes to add certain fields in current descriptors which describe the contents currently broadcast in an audiovisual network, these fields make it possible to identify audio and / or visual contents that are or will be transmitted in PUSH mode. The descriptor receiver is thus informed by the descriptors of the existence of the contents and can program internal devices to record them.

Firstly, examples of descriptors will be exposed, then, in a second step, the devices for transmitting and receiving the streams containing said descriptors and audiovisual documents, the receiver device being capable of recording said content and of reproduce it at the request of a user. 6.2 Description of transmitted data 6.2.1 General presentation of tables Figure 1 describes the signaling used to identify a document transmitted over a broadcast network (terrestrial, satellite or cable) in PUSH mode. The broadcast network is called "NET BROAD". The data packets of the audio and / or visual contents are transmitted according to a standard, for example that defined by the MPEG-PSI and DVB-SI specifications. The data is in the form of tables and descriptors that describe the objects (services, events, TS,) sent on the NET BROAD network. The MPEG-PSI and DVB SI standards specify the following tables: NIT, SDT, EIT, PAT, PMT. The NIT table defines the general structure of the network and indicates the list of transport flows (or TS for short, acronym for "Transport Stream" in English) and services broadcast. The SDT table gives additional information about the services, for example the plain name of a service. The EIT table indicates a list of events for each service. In particular, it indicates the event being broadcast. The PAT table lists all the PMT tables and therefore all the services present in the multiplexed stream. The PMT table contains the list of elementary streams (a PID identifies each elementary stream of the service), these elementary streams constitute a given service (example: list of audio languages, video, available subtitle). The PMT table contains all the information needed to select this service. During the installation of the services, the receiver searches on the network the NIT table to extract the information from the channels of the network, then the receiver is positioned on each channel to extract the SDT table in order to obtain for this channel the list services with their name and service identifier. Each table defined by a specific table identifier, contains a descriptor that specifies the size and nature of each field that comprise the data packets associated with a table. These tables are issued at regular intervals in the data stream, for example, a PAT table is emitted on average every 0.1 seconds, other tables can be issued in time intervals of a greater duration. The DVB standard does not specifically identify a document transmitted in PUSH mode in a multiplexed stream. This document has the particularity of being broadcast at a speed different from that of real time. Thus, such a document can be transmitted at a rate higher than that of the normal broadcast and thus can be downloaded more quickly than the content broadcast for reproduction in real time. The transmission of documents in PUSH can be carried out continuously, by the continuous reservation of a certain flow, or discontinuous, by the reservation of a certain flow during certain hours of the day or the night. The flow reserved for the transmission of documents in PUSH can be variable in time. The solution described also takes into account the constraints introduced by the existing equipment fleet both at the receiver level and at the head end. According to an exemplary implementation of the invention, the SDT table indicates the presence of a service transmitting documents in PUSH mode. The receivers can thus determine and present to the user a list of real-time broadcast services and services transmitting documents in PUSH mode. In the case of a selected service, the receiver searches for the PMT table corresponding to this service in order to extract the elementary streams. Figure 1 describes according to a particular embodiment, the way to report the document transmitted in PUSH mode within a service. The packets transmitting this document form a secondary stream including elementary streams transmitting: PAT, PMT tables, video packets, audio packets, any applications associated with this document, ... The structure of a transmitting stream a document in PUSH is identical to that of a stream broadcasting a service in real time. The identifiers or PIDs of the elementary streams of a document transmitted in PUSH mode are listed in the descriptor specific to the PUSH stream contained in the PMT table of the main stream. The dashed lines in Figure 1 indicate the PIDs pointed through the specific descriptor. In this way, no specific protocol being used, the method of transmission include the advantages: - There is no encapsulation of the data broadcast. As a result, there is no reduction in the useful rate. - The construction of the multiplexed stream can be realized with "standard" multiplexing equipment.

According to the standard, a single PAT table describing the available services is present in the multiplexed stream and this table has the number "0". The identification of the streams transmitting documents in PUSH is carried out with another PAT table having another number other than "0", it is the number "132" in FIG. 1. In this way, the receiver does not consider this table as the PAT of the main stream but as a table belonging to a data structure. Thus, by not showing the structure of the secondary stream in the main stream, the receivers do not detect secondary streams as video services transmitted in real time. The video and audio streams of the document in PUSH mode do not appear directly in the main stream, which prevents the multiplexers of the transmitter from affecting the signaling. The transmitter does not need to modify the PIDs of the packets transmitting the document in PUSH mode, so the internal signaling of the streams composing the document transmitted in PUSH mode remains coherent when it is recorded in a receiver.30 6.2.2 Introduction of the PMT Table Figure 2 shows an example of a PMT descriptor describing a service transmitting a document in PUSH mode. This descriptor contains one or more descriptors "PUSH service descriptor" identifying the elementary flows of documents in PUSH. These descriptors constitute an ordered list of elements that are inserted in the first loop of the PMT. The first element of the list is the PID of the PAT table (identified with the number "132"), the second is the PID of the PMT (number 133) identifying a document transmitted in a first secondary stream, the other elements identify secondary streams (audio, video, AIT, ...). This list allows the receivers to know the list of PID streams to be recorded to ensure the integrity of the audiovisual document transported in the secondary stream. The title "PID_list length" refers to the length in bytes of the next loop containing the list of PIDs constituting the document transmitted in PUSH mode. The title "Elementary PID" refers to a PID identifying the document transmitted in PUSH. The PMT described in Figure 2 may optionally contain a reference to an AIT table for associating an interactive service with the document. 6.2.3 Presentation of the EIT table The EIT table describing the document transmitted in PUSH contains in particular the following elements: - registration data: - start time: start of the distribution of the document, - duration: actual duration of the document, - running status : status of the broadcast. - Metadata in the descriptors: - content descriptor (optional): type of document (for example: drama, comedy .. - the complete list of attributes is specified in ETSI EN 300 468 V1.11.1 page 40. The receiver can use this field to filter the documents to be saved, - parental rating descriptor, - short event descriptor: file name + short description (option), - extended event descriptor (option): extension of the type of document.

Figure 3 shows other elements of the EIT table specific to the invention. These elements make it possible in particular to identify the document transmitted in PUSH mode and to program its recording at the receiver. These elements are as follows (non-exhaustive list): - file identifier: Identifier to use to access the file via the HbbTV API. For example: ServiceID + EventID - validity start date: The start date of validity of the document. - validity end date: The date of expiry of the document. - erasing_priority: Priority value defined by the headend. This value is used for managing the disk space of the receiver. In the case where the disk is full, on receipt of a priority document p, one or more priority documents less than p are deleted so as to free up space and allow the registration of a new document. - max error_percentage: acceptable percentage of errors. If a document is received with an error percentage greater than the one specified, this document is not retained. - content type: Type of document (for example: free or paid) - erasing order: Erasing order. This command deletes a document from the hard disk of the devices. Example: an adult document has been broadcast without specific signage being associated. The EIT containing the identifier of this document is rediffused with the "Erase Order" flag at 1. Upon receiving this EIT, the devices immediately delete the saved document. It has been said previously that the information contained in the PMT identifies the different secondary flows transmitting the document in PUSH. A receiver uses the information in this table to detect the presence of such documents and possibly present them to the user in a menu so that he can program their recordings. This menu is a possibility that does not exclude that the receiver itself makes the registration of all documents for later offer to the user. 6.2.4 Presentation of the SDT table An SDT table associated with a document transmitted in PUSH notably includes one or more of the following descriptors: - Component descriptor: - component type: description of the document of the flows (MPEG4 AVC, MP2 ...) the complete list is in the standard ETSI EN 300 468 V1.11.1 page 37. - Service descriptor: - service type: PUSH VOD (to be added in the table 81 of the ETSI EN 300 468 standard), - running status: used for the services non-continuous. - CA identify descriptor: Identification of Access Control (if used).

The PAT table associated with a document transmitted in PUSH has a classic structure, but is not identified with a PID number 0 which is reserved for the PAT of the main stream. The transmission frequency of the PAT is compatible with the DVB standard when replaying the TS stream after recording. On the other hand, there is no real time constraint on its broadcast frequency when transmitting the document in PUSH. 6.3 Description of a Stream Transmitter The main and secondary streams are transmitted by a server commonly called a "head end". An exemplary server 20 is illustrated in FIG. 4, according to a preferred embodiment. The server 20 comprises, in particular, an ALU 2.1 central unit, an MP 2.2 program memory in which at least one encoding program is recorded, a DB 2.3 database and a NET 2.4 I / O communication interface for exchanging data. Bidirectional way through the network 6 with receivers described later. The server 20 may have a TV I / O interface 2.5 to a NET BROAD broadcast network for unidirectionally transmitting audiovisual documents. The server 20 receives the audiovisual documents to be broadcast and stores them in its DB 2.3 database. Then, the server 20 organizes the diffusion and the transmission of the documents to the receivers 1. Before the transmission, and possibly during the recording, the documents are encoded in data packets according to the format defined by a standard, DVB by example. The data packets are broadcast to a NET BROAD broadcast network through the network interface 2.5, or to a bidirectional network 6 in order to be downloaded at the request of a receiver 1. The database DB 2.3 contains the both documents broadcast in real time and intended to be immediately reproduced upon receipt, and documents transmitted in PUSH mode without time constraints. Documents can be saved in the database in a format independent of the delivery mode. The server 20 multiplexes the packets of the main streams and the packets of the secondary streams according to the constraints of the broadcast network. Before it is sent, the server changes the PID of the PAT of the document in PUSH mode, which should not be numbered "0". 6.4 Description of a Stream Receiver FIG. 4 shows an exemplary embodiment of an audiovisual receiver 1 connected to a display device 2, according to a preferred embodiment. The audiovisual receiver 1 which is for example a decoder comprises an ALU 3 central unit connected to an MP program memory 12, TV 4 I / O reception means such as a demodulator and a demultiplexer for receiving digital data from a NET BROAD broadcast network using a receiving antenna. The TV 4 I / O reception means makes it possible to receive audiovisual services broadcast over radio channels. According to a particular embodiment, the receiver 1 may be provided with a NET I / O interface 5 for communication with a broadband access NET_BI 6 digital network for transmitting data streams. This network is for example Internet. The receiver 1 further comprises an infrared I / O signal interface Rem 7 for receiving the signals of a REM 8 remote control, a DB 9 memory for storing the service data, and A / V audio / video decoding logic. 10 for the generation of the audiovisual signals sent to the television screen 2. The receiver 1 also comprises an OSD 11 data overlay (from the English "On Screen Display" (literally meaning "display on the screen" The OSD circuit 11 is a text and graphics generator that can be used to display program guide menus, pictograms or images on the screen Receiver 1 can communicate through its I / O communication interface. NET 5 and NET_BI network 6, with one or more servers 20 of which an exemplary embodiment is described in FIG. 4.

The receiver 1 analyzes the contents of the table SDT and determines the PID of the table PMT describing the documents transmitted in PUSH mode (it is the PID number 11 as illustrated by the figure 1). According to a particular embodiment, when the document is saved in the memory DB 9, the receiver sets the PID of the PAT to 0. Thus, the structure of a document stored in the memory DB 9 is identical to that of a broadcast service. The audio and / or video documents transmitted in PUSH are filtered and stored in the receiver in the form of TS files containing MPEG 2 or MPEG 4, SD or HD streams. According to a particular embodiment, each TS has the same characteristics as the streams broadcast in TNT. In this case, the reproduction of the recorded documents is carried out without the addition of an additional decoder in the memory of the receiver. 6.5 Recording sequence To trigger a recording, receiver 1 analyzes the EIT packets and detects the PIDs signaling the transmission of a document in PUSH. Upon receiving each EIT packet, the receiver determines whether the associated document is for recording. If the type and / or identifier corresponds to a document to be recorded, the receiver schedules the start of the recording using the time of the "Start time" field specified in the EIT. The time reference used is identified in the contents of the TDT table. At the time of the specified start time, the receiver 1 records the contents of the PIDs reported in the document's PMT. The recording continues as long as the document is specified in the EIT and the "running status" field is set to "mn".

By default, the name of the file stored in the receiver is that of the "event narre _char" field of the "short event descriptor" descriptor. This file name can be used to make the link, at the level of the user interface, between the video files and associated metadata. In order for the beginning and the end of the transmitted documents to be correctly recorded by the receivers 1, the server 20 transmits the packets of the document only N seconds after the indicated recording time has been reached in the TDT. Likewise, the document being transmitted is reported as completed in the EIT as "N" seconds after the end of the broadcast of the packets to be recorded. Figure 6 illustrates the progress of the transmission of a document in PUSH mode. At time Ti, the EIT1 table being broadcast does not give any indication of the transmission of a document in PUSH mode. At T2, the EIT2 table describes the next presence of a document in the multiplexed stream by setting the "Running Status" field to the SIAFS ("starts in a few seconds") value indicating that a document will be transmitted in a few seconds .

In this way, the receiver 1 can prepare the recording. At time T3, the document is transmitted and the "Running Status" field of the EIT3 is set to "Run". If the bandwidth is insufficient to transmit the document and since it has no real time constraints, its broadcast can then be stopped, the field "Running status" of the EIT4 is then set to the value "Pausing "(Time T4). When resuming the transmission of the document identified in the EIT5, the "running status" field in the EIT changes from "Pause" to "SIAFS" (T5) and then to "Run" ( T6) just before sending the first packets of the document. When transmission is complete, the "Running status" field of the EIT7 is set to the "Stop" value for a specified duration, a few seconds and then at time T8, no further indication of the presence of this document appears. in the EIT8. After receiving the documents transmitted in PUSH, the receiver 1 has in its memory 9 a list of documents ready to be reproduced. The menu for presenting recorded documents may be specific to the receiver or may be transmitted according to the HbbTV standard, for example. If the application is broadcast, it can be reported in the PMT of the service and recorded with the audio and / or video data. In this way, documents transmitted in PUSH mode are accessible from HbbTV applications associated with a "Live" program offered for example by television channels. The invention is not limited to the embodiments that have just been described. In particular, the invention can be implemented by any device performing the encoding or decoding functions of a stream containing an audio and / or visual component.

Claims (3)

REVENDICATIONS1. Device (1) for receiving a multiplexed stream specified by the DVB-SI standard and organized in successive data packets comprising at least one main stream comprising a first PAT table identifying at least a first PMT table containing at least the list of the streams elementary of an audio and / or visual service being broadcast and intended to be reproduced in real time, characterized in that it comprises: - a determination means (3, 12) in the content of said first PMT table d a descriptor listing identifiers (PID) of elementary streams constituting a secondary stream, said secondary stream transmitting at least one audiovisual document without time constraint, - a means of reception (4; 5, 3, 12) of said audiovisual document using the data included in said descriptor transmitted in the stream. 2. Device (1) for receiving a multiplexed stream according to claim 1; characterized in that the first identifier (PID) of said descriptor is an identifier of a second table PAT identifying a second table PMT, the second table PMT containing at least the list of elementary stream identifiers transmitting said audiovisual document. A method for generating a multiplexed stream specified by the DVB-SI standard and organized into successive data packets comprising at least one main stream comprising a first PAT table identifying at least a first PMT table containing at least the list of elementary streams an audio and / or visual service being broadcast and intended to be reproduced in real time, characterized in that it comprises a step of insertion in said first table PMT of the main stream of a descriptor listing flow identifiers elementary elements constituting a secondary stream, said secondary stream transmitting at least one audiovisual document without temporal constraint. 5. 6. 7. 8. A method of generating a multiplexed stream according to claim 3; characterized in that the first identifier of said descriptor is an identifier of a second table PAT identifying a second table PMT, the second table PMT containing at least the list of elementary stream identifiers transmitting said audiovisual document. A method of generating a multiplexed stream according to claim 4; characterized in that the number of said first table PAT has the number 0, said second table PAT having a number different from O. A method of generating a multiplexed stream according to any one of claims 3 to 5; characterized in that it comprises a step of insertion of temporal indications determining the beginning and / or the end of the transmission of the secondary stream transmitting said audiovisual document. A method of generating a multiplexed stream according to any one of claims 3 to 6; characterized in that it comprises a step of inserting at least one temporal indication determining the beginning and / or the end of the validity of said audiovisual document. A method of generating a multiplexed stream according to any one of claims 3 to 7; characterized in that it comprises a step of inserting a priority indication for defining the erase order of audiovisual documents recorded in a receiver when there is not enough room to store a new document. 9. A method of generating a multiplexed stream according to any one of claims 3 to 8; characterized in that it comprises a step of insertion of an indicator that can take at least one of the values signaling the following states: beginning of transmission of an audiovisual document during a determined duration, transmission of a audiovisual document in progress, unfinalized stop of the transmission of an audiovisual document. A device (20) for generating a multiplexed stream specified by the DVB-SI standard and organized into successive data packets comprising at least one main stream having a first PAT table identifying at least a first PMT table containing at least the list elementary streams of an audio and / or visual service being broadcast and intended to be reproduced in real time, characterized in that it comprises: an insertion means (2.1, 2.2) in the content of said first PMT table of the main stream of a descriptor listing elementary stream identifiers constituting a secondary stream, said secondary stream transmitting at least one audiovisual document without time constraint. 11. Computer program product downloadable from a communications network and / or stored on a computer-readable medium and / or executable by a central unit, characterized in that it comprises program instructions for the implementation of at least one step of the method of generating a multiplexed stream according to any one of claims 3 to 9.