HK1131845B - Method of transmitting service information in various types of broadcasting networks and unit for processing said information - Google Patents

Description

Field of invention

The present invention relates to the network broadcast of digital data streams including services and information data to a plurality of receivers. In particular, it relates to the transmission and reception of information data on services provided by various types of broadcast networks. This information informs a user about the access and characteristics of the services available from receivers equipped with appropriate interfaces.

Background of the invention

The DVB (Digital Video Broadcasting) standard defines a service as a set of digital data managed by an operator and broadcast in a transport stream over terrestrial or satellite frequency or cable to a plurality of receivers/decoders.

The transport stream contains data from a service consisting, for example, of audio/video content accompanied by additional data such as subtitles, teletext or interactive applications and information about the service such as the description of the content, the broadcast schedule, access conditions, etc.

EP1464176 describes a method for using the data provided by the DVB-SI Event Information Table to access a stream broadcast in IP mode. A proposed event is associated with at least two sources and the system provides transparent access to that event regardless of its source. An appropriate receiver includes service information means for using event information data to access content broadcast under IP. These means use announcement and service description protocols to link the service channels provided by the digital content provider and the IP stream services.

FR2864869 discloses a system for broadcasting DVB services over an IP network in which the signalling information describing the network and the services offered is separated from the services themselves. A receiver connected to a two-way network detects services by first connecting to a first stream to extract location information on the network. These include data on the streams carrying the content of these services and data on the streams carried separating information on these services.

US2003/0078687 describes a method and system for automatically configuring an auditory environment for optimal sound reproduction based on the characteristics of the transmitted audio signal and the service being received. These characteristics, such as the broadcast of the signal in mono or stereo mode, are transmitted via standardized EIT (Event Information Table) event information tables used in the preparation of the Electronic Program Guide (EPG). Upon receipt of this information, the receiver is configured, if the equipment and system allow, to optimally operate, in this case in stereo mode and without user intervention. Depending on the data base, the receiver and the program guide may be used in a combination of the following:

EP1207698 describes a digital audio/video program receiver comprising a first and second receiving unit each receiving the programs from a first and second broadcast network respectively. These two networks are separate, such as a terrestrial broadcast or satellite broadcast network and an Internet broadcast network. A program received by at least one of the two receiving units is accompanied, at predetermined times, by switching instructions to determine whether a program is received by either of the two receiving units. The user stores in the receiver information such as a list of favorite programs.

EP1411723 describes a method of obtaining information about programs broadcast in a transport stream. This information is obtained from full or partial Internet links or URLs contained in the Service Information (SI) or Program Specific Information (PSI) including the Program Map Table (PMT) or Event Information Table (EIT). The receiver reconstitutes, if necessary, the full path or URL from the receiver's allocation ID data stored in the stream to download, from the defined content server, information about one or more programs broadcast in the stream.

US-B1-6920327 describes a method of data transmission using radio transmission systems between transmitter/receiver stations. A computer dynamically manages data transmission systems to communicate from at least one transmitter/receiver station. This management is based on a subscriber profile, the position of a transmitter/receiver station, and/or the transmission speed. A switching device calculates which radio transmission system is most appropriate and automatically switches from one radio transmission system to another when the quality of the current transmission declines.

In the systems of these documents, the receiver is responsible for exploring the services available on the network and extracts from the various tables the information necessary to compile a list of programs.

In some configurations, the receiver or decoder (also known as a set-top-box) is connected to a cable or antenna and a bidirectional IP network to receive DVB service streams. These two broadcast networks, each with their own parameters, result in specific processing of service information by the receiver.

Summary of the invention

The purpose of the present invention is to simplify the processing of service information data by the receiver and to ensure a transparent retransmission of this information over a DVB network without prior exploration of the services available on the IP network by the receiver.

This is achieved by a service information transmission method (see claim 1) and a service digital data flow processing unit (see claim 8).

A processing unit here corresponds to any receiver configured to receive and process broadcast digital data streams such as a set top box or a personal computer.

The method of the invention allows all available service information to be grouped in a table transmitted by the DVB network regardless of their source. The receiver can thus display this information by processing the DVB network stream alone without having to process the IP service stream information. The analysis of the different IP streams and the processing of service information data by the management center thus relieves the receiver of often considerable tasks.

The introduction of IP service information extracted from the IP network into lower level tables such as the Program Map Table (PMT) or the Event Information Table (EIT) involves an analysis of all services and programmes broadcast in the DVB stream in order to insert this information into the correct tables.

Of all the tables included in service information data, the NIT table is preferably used, which is located at the highest level in the hierarchy of service information tables with the SDT table and the BAT table. The use of these higher-level tables significantly reduces the analysis and processing tasks performed on the server side when entering IP services information and on the receiver side when determining the IP service corresponding to the DVB service being received.

In the event of problems with reception on the DVB network, the information displayed informs the user about the availability of equivalent services on the IP network.

Service information data is usually extracted from a structure called SD&S (Service Discovery & Selection) transmitted over the IP network. It essentially contains IP addresses and service descriptors. Depending on configuration, it may also include references to IP broadcasters.

The NIT table contains all service data made available to a user by an operator. In an example of transmission over the frequency spectrum, this table contains information necessary for the receiver settings to receive a DVB stream such as frequency, polarization, error correction parameters, data stream rates, etc.

In one variant, the NIT table can be supplemented with information from IP networks received by other means than the SD&S structure, such as files, databases or manual input.

Brief description of the figures

The invention will be better understood by the following detailed description, which refers to the figures given in the annex as a non-limiting example.

Figure 1 shows a set of receivers connected to an IP network and a broadcasting network in which the distribution of digital streams is organised by management centres.

Figure 2 shows a block diagram of a processing unit comprising two switchable receiver modules connected to a DVB and IP broadcast service network respectively.

Detailed description of the invention.

The block diagram in Figure 1 shows a plurality of receivers or set top boxes (STB1...STBn) receiving digital data from a DVB broadcast network and connected to an IP network. The management centres (CG1,..., CGn) dependent on the operators are responsible for organising the streams and their dissemination over the networks. In the example, the streams are transmitted to the receivers over the air by transmitters (E1, E2) or by cable (C) under the control of the management centres (CG1...CGn). The method of the invention is therefore implemented at the level of the management centres (CG1,..., CGn) which provide the services and information concerning standards which are governed by standards defined by the European Telecommunications Standards Institute (ETSI).

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The PSI data allows the receiver to be automatically configured to decode and decode the various program streams it receives.

These PSI data are structured into four types of tables which are transmitted in sections, namely: 1) The following table shows the number of programmes: It indicates for each multiplex service the location, i.e. the values of the PID (Packet Identifier) packets of the transport flow of the corresponding PMT (Program Map Table). It also provides the location of the Network Information Table (NIT).2) The CAT (Conditional Access Table) It provides information specific to conditional access systems used in the multiplex including the location of the Entitlement Management Message (EMM) administration message stream.3) The organization table of the PMT programmes (Program Map Table) It identifies and indicates the locations of the streams constituting each service and the location of the program clock reference fields for a service.4) The Network Information Table (NIT) Its location is defined in accordance with ISO/IEC 13818-1 MPEG-2, the data format not being included in this standard. It provides information on the physical network such as the designation of transmitters (hertz or satellite) to find other transport flows on the network.describes the organization of the flows, in particular it allows the receiver to configure itself automatically.

The PSI programme specific information is supplemented by data enabling the user to identify the services and events carried in a multiplex or network. The BAT (Bouquet Association Table) provides, in addition to the name of the package (set of programmes or services made available to users by an operator), the list of services available in each package.This table is optional.The SDT (Service Description Table) contains data describing services such as names and service providers.

The two upper mandatory levels NIT (Network Information Table) and SDT (Service Description Table) are required to set a receiver to a chosen program.

Information on the content of programmes is given in the EIT (Event Information Table) which refers to each service from its DVB identification. e information describes the different programmes by providing information similar to that found in a traditional TV programme magazine.

For example, information about all programs scheduled on the same day and the following 7 days will be transmitted to be displayed in the electronic program guide acting as a user interface for easy program selection. The main information contained in the EIT table is the name of the event, the start time, the duration of the program, its progress, its title, a summary textual description of the content, the definition of the image and sound format (16:9, 4:3, mono, stereo, etc.), the exact start time allowing for the actual start of a recording at the beginning of a program, in case of delayed broadcast of the program in question with the same VPS program (Video Program System).

Alternatively, BAT or SDT tables may also be supplemented with additional service information relating to broadcasting over IP networks in the same way as the NIT table, where the NIT table cannot be modified due to restrictions imposed by service providers.

ETSI TS 102 034 Digital Video Broadcasting (DVB); Transport of MPEG-2 Based DVB Services over IP Based Networks specifies the deployment of MPEG-2 DVB multimedia services on two-way IP networks.

The network information table (NIT) is not used in IP networks, the necessary information is transmitted in a service discovery & selection (SD&S) structure. This structure provides information on the services offered and how to access these services using IP addresses.

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In summary, most SI information from DVB networks is either transmitted transparently or transferred to SD&S structures before transmission over IP networks.

For broadcasting over DVB networks, the NIT table or other tables grouping SI data can be modified by adding IP network information from other sources such as files or databases without having to extract it from SD&S structures.

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The ETSI standards define the organization of the data streams transmitted with the information necessary for the reception of the services carried by these streams according to the configuration of the receivers. However, they leave some freedom as to the content of the tables, in particular the service descriptors that can be adapted to the characteristics of the networks to which the receivers are connected. Thus, the addition of a NIT table or other tables belonging to the SI service information according to the method of the invention is not contraindicated by the standards provided that the information introduced complies with the prescribed format and syntax.

Because DVB-SI service information is transmitted by sections identified by PID packet identifiers, the NIT table can be divided into several sub-tables, e.g. one per IP service broadcaster.

The diagram in Figure 2 shows a processing unit (STB) comprising a first receiver module (R1) configured to receive DVB stream services and a second receiver module (R2) configured to receive IP stream services. The unit (STB) also includes switching means (SW) to activate the reception of IP services with the second receiver module (R2) when DVB services with the first module (R1) become poor or impossible. The processing and display means (P/A) connected to the processing unit (STB) allow the user to present information about DVB and/or IP services broadcast on a television or other viewing screen.

The NIT, SDT or BAT table received by the first receiving module (R1), i.e. via the DVB type network, contains information on the services broadcast by the IP network.

In the event of a failure of the first receiving module (R1) to receive a service from the DVB network, the processing unit (STB) shall activate, either automatically or manually by the user according to the information displayed, the reception by the second receiving module (R2), i.e. via the IP network, to receive one or more services equivalent to the faulty service.

Claims (12)

1. Method for transmitting services information in a broadcasting network by at least one managing center (CG1...CGn) towards a plurality of processing units (STB1, STBn) connected on one hand to a digital data streams broadcasting network of DVB type and on the other hand to a digital data streams broadcasting network of IP type, said streams comprising content data of the services and additional information data on said services structured in tables adapted to the transmission protocol specific to each type of network, said method is characterized in that it comprises following steps:

   - exploring the streams broadcasted by the network of DVB type and the streams broadcasted by the network of IP type and extracting services information from these streams,

   - completing an information table, situated at the highest level in the hierarchy of the services information tables by services information including a descriptor comprising an identifier of a service of the network of IP type and an IP address corresponding to said service, said table being comprised in the DVB-SI services information transmitted by the network of DVB type.

   - transmitting the completed information table in the streams broadcasted by the network of DVB type towards the processing units, said completed information table contributing to reduce the analysis and processing tasks executed by the processing units during determination of the service of the network of IP type corresponding to a currently received service of the network of DVB type.
2. Method according to claim 1, characterized in that the completed information table consists of the network information table NIT defined according to the standards ETSI EN 300 468
3. Method according to claim 1, characterized in that the completed information table consists of the bouquet association table BAT or of the services description table SDT defined according to the standards ETSI EN 300 468.
4. Method according to claim 1 characterized in that the information table is completed with a reference of the broadcaster of the IP services.
5. Method according to claim 1 characterized in that the completed information table is transmitted divided into several sub-tables each attributed to a broadcaster of IP services.
6. Method according to claim 1 characterized in that the information table is completed with the services information extracted from the SD&S (Service Discovery & Selection) structure transmitted by the network of IP type.
7. Method according to claim 1 characterized in that the services information concerning the network of IP type are introduced into the information table from files or from databases.
8. Processing unit (STB) of digital data services streams comprising a first receiver module (R1) receiving digital data streams of the DVB type and a second receiver module (R2) receiving digital data streams of the IP type linked to means for processing and displaying (P/A) of broadcasted services information data, switching means (SW) able to activate the reception of digital data of a service equivalent to the service currently received with the second receiver module (R2) when the receiving conditions by the first receiver module (R1) are degraded, said processing unit (STB) is characterized in that it comprises means for determining the equivalent service from a services information table stored in a non-volatile memory and situated at the highest level in the hierarchy of the services information tables, said services information table containing descriptors comprising identifiers of services of the DVB type and IP addresses corresponding to said services of the DVB type.
9. Processing unit according to claim 8, characterized in that the equivalent service is determined by the network information table NIT defined according to the standards ETSI EN 300 468.
10. Processing unit according to claim 8, characterized in that the equivalent service is determined by the bouquet association table BAT or by the services description table SDT defined according to the standards ETSI EN 300 468.
11. Processing unit according to claim 8, characterized in that the reception of the digital data with the second receiver module (R2) is activated automatically when the conditions of reception with the first receiver module (R1) are degraded.
12. Processing unit according to claim 8, characterized in that the reception of the digital data with the second receiver module (R2) is activated manually according to the displayed information when the conditions of reception with the first receiver (R1) module are degraded.