FR2827463A1 - Television signal control system has decoder to extract control information for internet link to user - Google Patents

Abstract

A television signal control system has a decoder (100) to extract television services (ENS1) and information (ENS2) for control (148) of the received signal flow (113) by a remote user (114) over an internet network (112) using operating table (INFO2) and service (INFO1) information. Includes an Independent claim for a decoder using the system.

Description

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Method for controlling a stream of television signals received by a television decoder and associated decoder
The subject of the present invention is a method for controlling a flow of television signals received by a digital television decoder, and a decoder making it possible to implement this method. More particularly, the invention relates to a method in which various data received in the television signal stream are extracted in order to transmit to a remote interlocutor a message elaborated as a function of the extracted data. Analysis of the message thus transmitted can then allow conclusions to be drawn on certain operating characteristics of the digital television decoder.

 In general, the field of the invention is that of digital television. In this field, digital television decoders are used, in particular in order to access a set of services, or channels, of encrypted television. The television decoders are bodies performing an interface between television signal transmission systems, in particular digital television signals transmitted and organized according to the MPEG and DVB standards, and display monitors. Often, the monitor itself contains circuits for decoding these television signals, but this is not an obligation. The signals exchanged are most often digital signals, but a decoder can also have the ability to process analog signals. The transmission means which broadcast the television signals to these decoders / receivers are either conventional aerial transmission means (in frequency bands at emission from 17 to 862 MHz), or coaxial cables (in frequency bands for transmission from 110 to 862 MHz), or even optical, either re-transmission satellites which serve a region (in frequency bands for transmission from 10.3 to 12.8 GHz), or even broadcasting means digital terrestrial.

 Typically, the decoder comprises reception means for receiving the broadcast signals and formatting means for transforming the received signals into signals applicable directly on the control members of the display device. For a cathode ray tube, it is

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 for example commands applied to the scanning members and to the various electron guns producing colored pixels on the screen.

 Formatting is carried out by respecting, for each of the images to be represented, parameter tables, also called operating tables. There are different types of tables: first of all, the so-called SI tables, System Information-Information System-which, in the DVB standard, indicate a title of a broadcast program, a start time, an end time, as well that different characteristics. The content of the SI tables is of particular interest to the user because they lead to the display of information which allows him to choose the program he wants to view. There are also tables known as PSI, Program Specific Information-Program Specific Information, described in the MPEG standard, which are functional tables for identifying video / audio or data packets. They ultimately represent the transmission protocol and architecture of the digital packets transmitted as well as their meaning. PSI tables are used to display the images of a program viewed.

 In digital television, it is provided that the data constituting the different parameter tables are transmitted in the television signal stream (that is to say with the video signal itself). This data is distributed and organized in data packets. The transmitted data packets are arranged in sections, the sections conventionally comprising 1024 bytes or, in certain cases, 4096 bytes.

Packages from the same table are not necessarily grouped in the same section. They can be divided into different sections, possibly successive, interleaved with information packets relating to other tables or relating to video, audio, data or other signals. In each section, identifiers are used to assign the data packets to particular tables among others. On reception, a decoder does not know a priori how the data packets are distributed, but it can recognize a division of the sections. The decoder must therefore read the identifier in each section and reorganize the data to assign them to the correct tables. All the tables are edited by television operators or transport media managers, and are incorporated into this operator's flow, to be routed to the

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 users via different media.

 Figure 1 shows a representation of the different transmission media involved in the broadcasting of television signals. It also allows you to freeze the vocabulary used in the field. Transmission-reception means comprising satellites, cables or terrestrial re-broadcasting devices constitute transmission networks usable by different operators. For each operator using a transmission medium there is a NIT table, Network Information Table- Table d'Information de Réseau-, which indicates the name of the network, the network number, and, when it is a question of satellite connection and for each network multiplexes, which in this case are transponders, information such as the modulation frequency, the orbital position of bits, the polarization, etc. Similar information is contained in the NIT tables of the operators using the transmission media cable or terrestrial, the multiplexes being in this case called "channels".

 The information contained in the NIT tables are physical parameters essentially allowing a decoder to tune in frequency to pick up each multiplexed signal stream. Each NIT table includes, for a designated transponder, a list of services carried by the transponder. This list is normally limited, sometimes to 8 services, due to the bandwidth limitation reserved for a transponder. By service is conventionally understood what users call a television channel, for example a channel broadcasting during the day successive programs to each other.

However, the services may be audio only services, or data services, or other types of services.

 Each service is thus identified in the NIT table by a triplet of information: - information known as Original Network Id (ontwkjd) -identification of origin network.

 - information called Transport Stream Id (tsid) - Multiplex identification; this information typically designates one of the transponders in relation to the satellite.

 - information called Service Id (svcjd) -identification of Service-, which is in practice a number assigned by an operator who manages the satellite

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 for the transmission of this service.

 The MPEG2 standard makes it possible to multiplex several services in the same Transport Stream (TS) or channel. This standard is supplemented by the DVB standard which allows the constitution and change of service, or zapping on several transponders or channels. Services are always identified by the information triplet (ontwkjd, ts ~ id, and svc ~ id). Each operator therefore broadcasts more or less complete signaling allowing the constitution of a list of accessible services. In this context, the connection parameters are either entered by the user or frozen in the decoder.

 In the data intended to constitute the NIT table, the decoder essentially retrieves the triplet according to the DVB standard as well as the physical parameters of the transponder. Each transponder also transmits an SDT table which includes sub-tables. Each sub-table describes each of the services which are conveyed by the transponder. These services can be part of the services distributed by the transponder in question or by another transponder. This is identified from the NIT table.

 In addition, for each operator using a transponder or a channel, a table called PAT, Program Association Table-Table of associated programs, is broadcast. Such a table provides information, for its part, on the list of PMT, Program Map Table-Table of program components, which are associated with each of the services.

 At the service level, there are tables called EIT Event Information Table-Table of events, and PMT tables. The EIT tables refer to each service, from the identification triplet established according to the DVB standard, and indicate for this service the start time, the duration or the end time, the status, as well as others information relating to a broadcast program. The EIT tables are moreover split into ElTp tables and into ElTf tables which respectively constitute a table corresponding to the present instant (p, for "present"), and as well as another table corresponding to a following instant (f, " following "). The two tables ElTp and ElTf are of the same structure, but each has an identifier allowing it to be distinguished.

 Ultimately, an entire architecture of tables is thus distributed, in

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 particular according to standard EN 300 468, and the purpose of the decoder is to reconstruct all the tables in order to have adjustment information as well as information to be displayed in display for users.

 In practice, in the flow of the packet sections, represented in FIG. 2, tables, for example the NIT, SDT and EIT tables are transmitted in pieces distributed in time, one after the other, according to rules of distribution respecting standards.

 Usually, digital television decoders are made available to subscribed users by television operators who broadcast a set of services called digital package. These operators thus rent a device which allows each of their subscribers, on the one hand to receive and decrypt a set of television signals corresponding to the different television services which constitute their digital package and, on the other hand, to receive a set of operating signals, which allow the reconstitution of the various tables transmitted in a multiplexed manner in the television signal stream, so that the decoder performs the various decryption operations and possibly updates and / or triggers certain functionalities of the decoder.

 However, no means of controlling the flow of the received signals is implemented within these decoders. In other words, the digital television decoder is programmed to receive and organize data contained in the different signals, in particular to constitute the different tables, but no device internal to the decoder is provided to control this signal flow. Such control could however be advantageous in different situations.

 First of all, controlling the flow of signals could make it possible to determine what data is actually extracted from the flow to obtain a particular service, and thus make it possible to directly obtain a set of information to determine which are the different services. which have been or are being viewed by a user of the decoder.

 Then, controlling the flow of signals received by the decoder could make it possible to obtain various valuable information in the event of a malfunction of the decoder: such a malfunction can notably occur when an operator transmits bad data or bad parameters intended for constitution. different tables of

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 previously described operation. In such a case, the operating tables contain erroneous data and no longer allow, for example, correct extraction and organization of the data relating to the services to be restored. Such a malfunction can also interfere with the updating of certain functionalities of the decoder. In the state of the art, when such a problem is observed, it is necessary to set up specific equipment to record the signal stream as it is received by the digital television decoder and to extract from this stream the various data. intended to constitute the various operating tables.

A subsequent analysis of these tables then makes it possible to detect which are the erroneous parameters, the operator being able then to correct the emission of these parameters. In addition, when a manufacturer of a digital television decoder has sold decoders to a foreign operator, this type of problem is even more troublesome to resolve since it is necessary to go, with the appropriate equipment, to the distant broadcasting area. of the operator to carry out the various recording of the signal flow actually received by the digital television decoders.

 The method and the digital television decoder according to the invention make it possible to overcome all of the problems which have just been exposed. In fact, in the invention, provision is made to store, within the digital television decoder, various data which will make it possible to control the information flow received. This data can be revealing data, characteristic of the television service that the decoder has extracted - or is in the process of extracting - from the received signal stream, and / or data usually intended for the constitution of operating tables. In the invention, it is then planned to transmit, directly from the digital television decoder to an appropriate interlocutor, information exploitable by the latter. This information can take the form of a message intelligible to the remote contact, so that the latter can control the various services which have been extracted from the received stream and / or the constitution of the various operating tables.

 The invention therefore relates to a method for controlling a flow of television signals received by a television decoder, the signal flow being composed, in a multiplexed manner, of a first set of data corresponding to television services, and of a second set of

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 data for constituting operating tables, the method comprising the various steps consisting in: - extracting from the first set of data a first group of data associated with a particular television service; and / or - extract from the second set of data a second group of data to develop the different operating tables corresponding to the particular television service; characterized in that it comprises the additional steps consisting in: - storing a first item of information relating to the first group of extracted data and / or a second item of information relating to the second group of extracted data; - format the stored information to constitute a message that can be transmitted by means of a communication interface of the decoder; - transmit the previously created message (s) to a remote party.

 In a particular embodiment, the transmission of messages is carried out via a network of the Internet network type, possibly at regularly spaced times or following an appropriate instruction transmitted by the remote interlocutor or by a user of the decoder. Furthermore, the storage and formatting steps can be implemented as soon as a user selects a new television service.

 According to the cases envisaged, the first information relating to the first group of data possibly extracted from the first set of data can make it possible to identify the television service with which it is associated, and the second information relating to the second group of data possibly extracted from the second set data can be used to reconstruct one or more operating tables as actually received by the decoder. In the second case envisaged, the second stored information item corresponds to several occurrences of the table or of each operating table to be reconstructed, these different occurrences possibly corresponding to consecutive occurrences in the signal stream received from the table or from each reconstructable table.

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 The remote party can be different depending on whether the transmitted message has been formatted from the first information or from the second information. Furthermore, the transmitted message may not include information relating to the identification of the decoder transmitting said message.

 Another object of the present invention is a digital television decoder capable of implementing the method according to the invention.

 The invention and its different applications will be better understood on reading the description which follows and on examining the accompanying figures. These are presented for information only and in no way limit the invention. The figures show: - in Figures 1 and 2, already described, a known architecture suitable for broadcasting a stream of television signals; - in Figure 3, a schematic representation of the digital television decoder according to the invention.

 FIG. 3 shows a digital television decoder 100 according to the invention, which makes it possible to implement the method according to the invention. The decoder 100 comprises a reception module 101 for television signals, which receives via an antenna 102 a stream of available signals 113. The signal stream thus received is composed of a first set of data ENS1 constituting several audio and / or video signals multiplexed, each signal corresponding to an audio and / or video service sent by an operator. In the stream, there is also a second set of data ENS2, multiplexed with the first set of data ENS 1, constituting the set of information necessary for the constitution of the operating tables.

 The reception module 101 could also be connected to a cable television network or to a satellite reception system. Furthermore, the reception module 101 is connected to a control circuit 103 of the reception module 101. The control circuit 103 transmits to the reception module 101 a control signal indicating which service it must extract from the set of available flows received by the antenna 102. To this end, the reception module 101 consists of a tuner 104 which makes it possible to select, thanks in particular to the information contained in the NIT tables, a given carrier frequency corresponding to a given stream. Within

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 of the reception module 101, the tuner 104 is connected to an extraction module 105 which in particular makes it possible to extract from the signal stream selected by the tuner 104 a determined service, in accordance with the instructions contained in the signal transmitted by the control module 103. The signals relating to the extracted service are digitized within the reception module 101.

 A first sensor 106, in this infrared example, receives signals emitted by a remote control 107. An infrared cell of the first sensor 106 delivers a signal which allows the user to control the control circuit 103. The digitized signals coming from the module reception 101 are sent to a video memory 108 via a first bidirectional communication bus 109. At the output of the video memory 108, the different signals are transmitted to the different playback devices. A program memory 110 is intended for the storage of different applications that can intervene within the decoder 100, in particular for the implementation of the method according to the invention.

 A microprocessor 117 is connected by means of a second bidirectional communication bus 118 to the program memory 110, to the reception module 101, to the control circuit 103, to a data memory 115 and to a communication interface 111. The microprocessor 117 is also connected by means of a unidirectional link 119 to a second sensor 120 which is preferably similar to the first sensor 106. The user can thus trigger directly, by means of the remote control 107, the implementation of applications contained in the program memory 110. In other embodiments of the decoder according to the invention, these applications can be replaced by specific electronic circuits.

 The communication interface 111 makes it possible to exchange information with a communication network 112 external to the decoder.

In a preferred example, the communication network is the Internet. The second bidirectional communication bus 118 carries control, address or data signals. The first unidirectional communication bus 109 essentially conveys information relating to the images to be displayed on a display device.

 The two communication buses 109 and 118 could be combined in

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 a single bus. The microprocessor 117 manages in particular all of the applications of the program memory 110. The two sensors 106 and 120 can receive signals from the same remote control 107. In a variant of the invention, the two sensors 107 and 120 can be combined .

 Furthermore, it is obvious that the elements shown in FIG. 3 can be placed in any device other than the decoder 100 connected to a television, or in the television itself; if the invention is described in the context of a digital television decoder, the term decoder must be interpreted very broadly so as to encompass all the devices capable of receiving audio and / or video signals and capable of organize and play back these signals on a display device.

 The operation of the digital television decoder 100 according to the invention is now explained, essentially in the context of the implementation of the method according to the invention.

 In known manner, the program memory 110 includes an operating system 140 called the "OpenTV" operating system. This operating system includes in particular a module 141 called PSI / SI module, which allows the extraction, from the stream 113 of television signals received by the antenna 102, and more particularly from the second set of data ENS2 grouping all the data called operating, different data intended to constitute the different operating tables necessary for the rendering of a service, that is to say the tables specific to this service and necessary for the operation of the decoder 100. These different data are designated as being a second group GR2 of data. The operating tables are thus formed and are interpreted by the operating system 140 to organize the first set of data ENS1, which is constituted by the set of data actually relating to the various television services available in the stream 113, and for restore on a television screen type rendering unit a first group of data GR1 corresponding to a particular service selected by a user.

 However, in the usual operation of a digital television decoder, the various operating tables formed are constantly renewed, their transmission in the signal flow of

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 television being cyclical. With each new occurrence of an operating table in the received stream, the old operating table is replaced by the new table. The frequency of the occurrences of the different tables varies according to the tables considered, each of the tables being generally renewed several times per minute. Consequently, as soon as a new occurrence of an operating table replaces the old corresponding table, there is no more trace, no more information, within the decoder 100, relating to the old operating table .

 In the invention, an application 142 has been provided, called a storage application, which makes it possible to store a second piece of information INFO2 associated with the data relating to the old operating tables after they have been replaced by new operating tables. The second information INFO2 can directly correspond to the old tables which are thus written in a specific zone 150, called table memory, of the data memory 115. The second information INFO2 can also correspond to codes making it possible to reconstruct the old operating tables .

 The storage operation in the table memory 150 can be carried out systematically for each operating table as soon as it is replaced by a new operating table, or systematically at regular time intervals. In the latter case, an application 143 called a "timer" application is used to trigger the memorization operation in the memory of tables 150 at the different times regularly distributed over time; all the old tables are not necessarily memorized.

 In another embodiment of the method according to the invention, the storage operation in the table memory 150, triggered by the storage application 142, is only implemented following a specific instruction received by the digital television decoder 100. To this end, an application 144, called the trigger instruction detection application, is provided in the program memory 110.

The specific instruction can be, according to the different embodiments of the invention, either issued by a user, for example by means of his remote control 107, or issued by a authorized remote party via

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 the communication interface 111. In the latter case, the instruction detection application 144 provides for checking the identity of the remote interlocutor.

 The storage application 142 also intervenes to store a first item of information INF01 produced from the first group of data GR1 corresponding to a particular service selected by a user. The first piece of information INFO1 is also usually not stored in the digital television decoder 100. A specific area 151, called the service memory, is provided for this purpose in the data memory 115. The first piece of information INF01 is associated with the various television services which have been extracted, by the decoder 100, from the received signal stream. To develop this first information INF01, an application 145, called an application for extracting data relating to the services extracted, intervenes. This application has the function of constituting the first information INFO1 so that it comprises information, teaching relating to the television services extracted from the stream received 113, as well as possibly a duration of extraction of each service. This information is produced in particular from the extraction module 105 and an application 146 called service change detection.

 In general, the storage application 142 uses parameters contained in a specific area 152, called the configuration memory, of the data memory 115. In this configuration memory 152, there is a set of parameters, among which : the list of frequencies to be traversed in the stream received 113 in order to extract different tables, the nature of the operating tables to be memorized, the number of occurrences to be memorized for each of the tables, the identity of the different parties authorized to trigger the storage operation, the nature of the information (service identification, extraction duration, etc.) to be taken into account in order to develop the first information INFO1, parameters relating to the transmission of the various groups of stored data, etc.

 Once the first information and / or the second information has been stored, and before being transmitted to a remote party, they must undergo a formatting operation, performed by means of a formatting application 146, in order to be available in a format

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 compatible with the transmission operation to a remote interlocutor which will follow.

 Once formatted, the first information and / or the second information constitute a message which will be transmitted, via the communication interface 111, to a remote partner 114. An application 147, called transmission application, is implemented for this effect. It makes it possible to transmit, for example via the Internet 112, the elaborated message.

Beforehand, an application 148, known as interlocutor choice, will have been implemented to determine to which remote interlocutor the elaborated message must be sent. To this end, a list of potential interlocutors may have been previously stored in a specific area 153 of the data memory 115. Typically, if the message produced has been formed from a first group of data, the message will be intended to a television operator, and if the message developed was made up from a second group of data, the message will be intended for the manufacturer of the decoder. According to the invention, the message produced can be sent directly to the appropriate interlocutor according to the nature of the message, that is to say according to the group of data having served to prepare the message.

 Preferably, in the invention, no information relating to the decoder transmitting the message is included in the message transmitted to the remote interlocutor, especially in the case where the message was produced from the second group of data.

 Thus, thanks to the method according to the invention and to the associated decoder, a television operator can obtain information on the frequency and the quantity of extraction of its services from the television stream, and a manufacturer of decoders can quickly obtain, without traveling and without using specific measuring instruments, information relating to the constitution and content of the various operating tables; in the latter case, it can quickly detect a malfunction, report it to the operator concerned, who can instantly rectify the shooting.

 Depending on the use that can be made of the decoder and the method according to the invention, different quantities of decoders must be able to implement the method according to the invention: in fact, in the case of a use for recovering operating tables, only a small number of decoders in service over a large area of territory

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 is sufficient ; in the case of an implementation of the method according to the invention by a television operator, a larger quantity could be envisaged so that the latter can obtain statistics as precise as possible.

 Finally, it is obvious that the various applications implemented in the method according to the invention can be integrated into the operating system used, for example the "OpenTV" operating system, or be produced in the form of specific electronic circuits. .

Claims (12)

1-Method for controlling a stream (113) of television signals received by a television decoder (100), the stream (113) of signals being composed, in a multiplexed manner, of a first set (ENS1) of data corresponding to television services, and a second set (ENS2) of data to constitute operating tables, the method comprising the different steps consisting in: - extracting from the first set (ENS1) of data a first group (GR1) data associated with a particular television service; and / or - extract from the second set (ENS2) of data a second group (GR2) of data to develop the different operating tables corresponding to the particular television service; characterized in that it comprises the additional steps consisting in: - storing a first piece of information (INF01) relating to the first group (GR1) of extracted data and / or a second piece of information (INF02) relating to the second group (GR2) of extracted data ; - formatting the first information (INF01) and / or the second information (INF02) stored to constitute a message that can be transmitted by means of a communication interface (111) of the decoder (100); - transmit the message (s) previously created to a remote party (114).  2 - Method according to the preceding claim characterized in that the transmission of messages is carried out via a network (112) of the Internet network type.  3 - Method according to one of the preceding claims characterized in that the steps of storage and shaping are implemented as soon as a user selects a new television service.  4 - Method according to one of the preceding claims characterized in that the step of transmitting messages is implemented at regularly spaced times.  5 - Method according to one of claims 1 to 3 characterized in that <Desc / Clms Page number 16>  the message transmission step is implemented following an appropriate instruction transmitted by the remote partner (114) or by a user of the decoder.  6 - Method according to one of the preceding claims characterized in that the first information (INF01) relating to the first group (GR1) of data extracted from the first set (ENS1) of data makes it possible to identify the television service with which it is associated .  7 - Method according to one of claims 1 to 5 characterized in that the second information (INFO2) relating to the second group (GR2) of data extracted from the second set (ENS2) of data allows to reconstruct one or more operating tables.  8 - Method according to the preceding claim characterized in that the second information (INF02) stored corresponds to several occurrences of the table or of each operating table to be reconstructed.  9 - Method according to the preceding claim characterized in that the different occurrences are consecutive occurrences of the table or of each table to be reconstructed.  10 - Method according to one of the preceding claims characterized in that the remote contact (114) is different depending on whether the transmitted message has been formatted from the first information (INFO1) or the second information (INF02) .  11 - Method according to one of the preceding claims characterized in that the transmitted message does not include information relating to the identification of the decoder (100) transmitting said message.  12-digital television decoder (100) capable of implementing the method according to one of the preceding claims.