WO2023191656A1

WO2023191656A1 - System for forming and transmitting a transport stream

Info

Publication number: WO2023191656A1
Application number: PCT/RU2022/050320
Authority: WO
Inventors: Дина Анатольевна ГУРТОВАЯ; Максим Станиславович САМСОНОВ
Original assignee: Общество с ограниченной ответственностью "Цифра"
Priority date: 2022-03-31
Filing date: 2022-10-09
Publication date: 2023-10-05

Abstract

A system and method for forming and transmitting a transport stream in a virtual channel service includes a transmitting side of a satellite broadcasting system, where an EPG server is provided with means for generating service metadata, scheduling events on virtual channels and selecting content events from linear broadcasting channels, said events being selected according to criteria set on the transmitting side for each virtual channel and being broadcast consecutively within the framework of the service and simultaneously with the corresponding broadcast of the event by the linear channel. For each event selected, the following are established: an identifier of the corresponding virtual channel, and a note of the use of the event on that virtual channel. A CAS subsystem generates for each linear and virtual channel, or groups thereof, control words, while also encrypting the session keys thereof, and ECM and EMM messages containing said words and establishing access rights to the broadcast of a linear channel event on a virtual channel and the cessation of said rights once the event is over.

Description

TRAFFIC FLOW FORMATION AND TRANSMISSION SYSTEM

Purpose and scope

The group of inventions relates to the field of satellite broadcasting and can be used in its organization and the creation of dedicated “virtual” television channels.

Prior Art

Digital television systems are often characterized by the presence of a large number of mainly audiovisual channels, which the user can switch and display as desired (provided he has the appropriate access rights to each channel). Therefore, the choice of various materials that can be viewed at any time is very extensive, which provides the user with the opportunity to personalize television to a certain extent “for themselves.” However, for most users, keeping track of all the content on offer, categorizing it precisely according to their tastes, and scheduling ("programming") the output of programs of interest to them is either too difficult or not suited to their inclinations.

In addition, broadcast advertising materials, which are a significant (and often vital) source of income for a broadcaster, are usually of interest only to a relatively small part of television viewers. At the same time, targeted delivery of advertising materials to the relevant target groups is often difficult (and in most conventional digital television systems, completely impossible) and ineffective.

In publication US20060156341 (Samsung Electronics Co Ltd, 2005), a device solution for generating a virtual channel is disclosed containing a virtual channel configuration module for setting any one channel from a set channels as a virtual channel per user; and a virtual channel processing module for registering a program selected by a user who has installed the virtual channel in a list of programs associated with the virtual channel. A virtual channel can be set for each user, so that a program to suit every taste can be viewed, even if multiple users are using the same TV, with minimal manual input required via the remote control or the TV's built-in selection buttons.

US20040205815 (Microsoft Technology Licensing LLC) discloses a solution in which an implementation associates a virtual channel with each of one or more recorded programs. A virtual channel preview guide is generated to display various virtual channels and their associated recorded programs. When you select a virtual channel, a preview of the recorded program associated with the virtual channel starts. In another implementation, the virtual channel preview guide includes program identifiers, each of which corresponds to a recorded program, and includes virtual channel identifiers, each of which is associated with a different program identifier. The virtual channel preview guide also includes a selectable control, such as a program ID or virtual channel ID, that can be selected to trigger a preview of the recorded program. In addition, the virtual channel preview guide includes a preview to display a preview of the recorded program.

The closest solution to the solution under study is the technology for forming user channels disclosed in patent publication US20090320072 (Microsoft Corporation, 2008). The technology is a system and method for generating a virtual channel in an electronic program guide. Scheduling commands, which are customizable by the user, specify the content that should be presented for selection in the virtual channel. Scheduling instructions are executed in order of priority. The virtual channel is populated with content descriptions based on the execution of instructions planning. After the virtual channel is initially filled with content, broadcast intervals are defined in the virtual channel. In one embodiment, each broadcast interval is filled with different content based on the broadcast interval setting set by the user. In another embodiment, each broadcast interval remains an empty schedule entry on the virtual channel.

The disadvantages of the above analogues and the prototype include the need for the formation and use of a virtual channel to increase the used transponder capacity, to organize the recording of the content of the virtual channel on the subscriber device and the need for an additional storage device to store the recorded content, as well as the need for playback of the virtual channel content of its complete descrambling, both within the virtual channel and outside it. In addition, known solutions are built, mostly based on user preferences, i.e. is formed on the client device, which complicates the process of forming this kind of individual channel, and also reduces the protection of the recorded content. In this case, a system for generating and transmitting a transport stream of a virtual channel, including at least a multiplexer formed on the transmitting side, equipped with means for generating a transport stream of broadcasting linear channels, an EPG server of an electronic program of television programs, equipped with means for generating a schedule of content events of linear broadcast channels, and a conditional subsystem access CAS, which includes an encrypting device equipped with encryption and access control tools to the encrypted content of linear channels, usually require either copying and recording the content of the linear broadcast channel into the memory of the transmitting or receiving party for its playback as part of a virtual channel and/or do not provide limited access to a linear broadcast channel, the event of which is included in the schedule of the virtual channel. As a rule, for analogue solutions, the generated transport stream assumes unconditional descrambling of the linear channel content in the presence of access rights to the virtual channel. Or it requires an additional storage device to store recorded content. Thus, known solutions for organizing a virtual channel require significant complexity of the system broadcasting while reducing the level of content protection and increasing the risk of unauthorized access to programs of linear broadcast channels.

The essence of the invention

The present invention is aimed at eliminating the problems inherent in the prior art.

The technical result achieved by the claimed invention is to expand the operational capabilities of the broadcasting system by increasing the reliability of the formation of the transport stream of the service providing virtual channels, providing expanded capabilities for broadcasting content without increasing the transponder capacity and memory capacity of the transmitting side, while maintaining or increasing the level of content protection.

The claimed technical result is achieved by using a system for generating and transmitting a transport stream of a service for providing virtual channels, including at least an EPG server for an electronic program of television programs formed on the transmitting side and connected to each other and to the multiplexer by communication lines, equipped with means for generating a schedule of content events linear broadcast channels, and a conditional access subsystem CAS, including an encrypting device equipped with means of encryption and access control to the encrypted content of linear channels, and the multiplexer is equipped with at least means for generating a transport stream of broadcast linear channels, differing from the prototype in that

- the EPG server is additionally equipped with tools for generating virtual channel service metadata and virtual channel event schedules, with the ability to compose a selection of content events of linear broadcast channels, selected according to criteria preset on the transmitting side for each virtual channel and broadcast within the service’s virtual channels sequentially in time and simultaneously with the corresponding broadcast of the linear channel event, with the setting for each sampling event of the identifier of the corresponding virtual channel and the mark of the use of the event in its composition;

- and the CAS subsystem is equipped with means for generating control words encrypted with session keys, as well as ECM and EMM messages containing them, for each linear and virtual service channel or their group, with setting access rights to broadcast a linear channel event specified in the schedule as part of a virtual channel and suspending it at the end of the event.

In one of the variants of the claimed solution, the EPG server is preferably equipped with means for generating two types of metadata of virtual service channels: basic metadata and additional metadata, where

- the main metadata represents the schedule of each of the virtual channels with a directory of virtual channels, where the schedule consists of events broadcast as part of linear broadcast channels, marked in a way preset in the system when forming a selection of virtual channel events.

- additional metadata is graphical data, at least including a technology break banner and a channel logo.

In yet another embodiment of the claimed invention, the basic metadata of the virtual channels contains event parameters, including description, start and end time of the event, parameters of the linear broadcast channel in the SNT transport stream, virtual channel identifier, and virtual channel parameters, including the name of the virtual channel, position in list of channels, links to each of the additional metadata files with reference to the virtual channel. In this case, the main metadata of the virtual channel service is preferably formed for transmission in the form of a data carousel stream, and additional metadata in the form of an object carousel stream. While in the transport stream the main metadata of the service’s virtual channels is made in the form of a file in JSON format, additional metadata is in the form of an archive file containing graphic data files.

In yet another possible embodiment, the CAS is provided with content encryption capabilities such that the same broadcast event is encrypted with a common control word, which in turn is further encrypted with different session keys for each linear and virtual channel or group thereof. In this case, the CAS conditional access subsystem can be equipped with content encryption tools in accordance with the DVB CSA algorithm.

In another embodiment, virtual channel metadata can be generated with the ability to broadcast in one service on one transponder, and equipped with service information with a link to a service with metadata of virtual channels with the ability to detect a service with metadata in the transport stream. Moreover, the service information is preferably equipped with a Linkage descriptor added to the network information table of the NIT stream, making it possible to provide virtual channel service to the end user without a user feedback channel. In this case, the service information of the Linkage descriptor may include at least: parameters for broadcasting SNT virtual channel metadata, a service identifier with virtual channel metadata, and a version of the virtual channel metadata format.

An embodiment of the claimed invention is possible, in which the transport stream at the output of the multiplexer is an MPEG-2 transport stream and includes at least: linear broadcast channels, the content of which is also used as part of virtual channels; basic and additional metadata of the virtual channel service; Linkage handle; MPEG-2 transport stream service tables including: RMT program structure table; CAT conditional access table; NIT network information table; TDT date and time table; BAT table of program groups.

The claimed technical result is also achieved by using a method for generating and transmitting a transport stream of a virtual channel service, including sequentially performed stages, at which at least:

- form, according to preset criteria on the EPG server of the transmitting party, a directory of virtual service channels containing at least the name of the channels and their position number in the list of broadcast channels, and a schedule of events of virtual service channels by arranging a selection of content events of linear broadcast channels broadcast within virtual channels of the service sequentially in time and simultaneously with the corresponding broadcast of the linear channel event, setting for each sampling event the identifier of the corresponding virtual channel and marking the use of the event in its composition, with the subsequent generation of metadata for each virtual channel,

- receive and encrypt control words generated by the scrambler of the conditional access subsystem, generate session keys and containing their ECM and EMM messages of broadcast channels and virtual channels of the service system, and the encryption of the same event broadcast as part of the linear and virtual channels is carried out by a common control word additionally encrypted with various session keys for each linear and virtual channel or their group with setting access rights to broadcast a linear channel event specified in the schedule as part of a virtual channel and suspend it at the end of the event, and transmit metadata files of the virtual channel service to the input of the multiplexer, where they form a transport stream by embedding service metadata into the transport stream of the content of linear broadcast channels and transmit it to the client input devices.

In this case, in one preferred embodiment, at the stage of forming the metadata of the virtual channels of the service, the main and additional metadata are formed, where the main metadata of the virtual channels of the service represent the schedule of each of the virtual channels with a directory of virtual channels, and the additional metadata are graphical data, according to at least including a technological break banner, installed in pauses between adjacent broadcasts of virtual channel events, and the channel logo.

In another embodiment, on the EPG server, the main and additional metadata of the virtual channel service are formed into streams, where the main metadata of the virtual channel service is formed as a data carousel stream, and the additional metadata is formed as an object carousel stream.

In yet another embodiment of the invention, the transmitting part of the CAS server additionally generates, stores, uses and automatically updates on a schedule session keys of CAS technology packages used to control access to broadcast events of linear channels through a virtual channel.

An implementation option is also possible, according to which additionally, on the transmitting part of the CAS server, EMM messages are generated with access control commands and session keys for technology packages of virtual channels, ensuring control of subscriber access to the content of the virtual channel service in modes in accordance with data on existing subscriptions received from the billing system and/or free access of subscribers who have authorized equipment and activated the functionality of virtual channels according to parameters preset in the system.

In another embodiment, when generating an MPEG-2 transport stream using a multiplexer, additional service information is built into the transport stream, which is subsequently transmitted to the input of the client device, which is a Linkage descriptor in the network information table (NIT), ensuring dynamic discovery by the client device of virtual channel service metadata in the transport stream, and on the client device discovering the metadata service in the transport stream through said Linkage descriptor without a user feedback channel.

In another embodiment, in any embodiment of the claimed invention, when generating a schedule of virtual channels of the EPG service by the server, when sampling events for a virtual channel broadcast by different linear broadcast channels intersect in time, an event with an earlier broadcast time is added to the schedule, and for the time of absence of display events of linear broadcast channels, a technological event pre-installed in the service system is added to the virtual channel schedule.

It is obvious that both the previous general description and the following detailed description are given for example and explanation only and are not intended to be limiting of the claimed group of inventions.

Any feature relating to one aspect of the invention may be applied to other aspects of the invention in any suitable combination. In particular, features of aspects of methods can be applied to aspects of systems and devices, and vice versa.

Brief description of drawings

Below, by way of illustrative examples only, preferred features of the invention will be described with reference to the accompanying graphical figures: FIG. 1 is a general diagram of a broadcast network; Fig.2 is an example of generating a schedule with setting a technological break mark: a) one virtual channel; b) two virtual channels; FIG. 3 is a diagram of the components and process of ensuring content protection; Fig.4 - switching according to the virtual channel schedule.

It should be noted that the accompanying drawings illustrate only a portion of some of the most preferred embodiments of the invention and should not be construed as limiting its contents, which include other embodiments thereof.

Feasibility of the invention.

The claimed group of inventions relates to the field of organizing satellite broadcasting, namely to a system and method for generating and transmitting a transport stream for the service of providing virtual channels. Since the claimed solution is part of the general system of the service for providing virtual thematic channels to the end user, the features of its implementation in the presented example implementation are considered in connection with the general solution of the service system for providing virtual channels.

As part of the description of an example of the implementation of the stated solution, the following terms and abbreviations are used:

AC (Access Criteria) - access criterion;

CAS (Conditional Access System) - access restriction system; SOD;

CW (Control Word) - control word;

CWG (Control Word Generator) - control word generator;

DVB (Common Scrambling Algoritm) - a unified scrambling algorithm;

ECM (Entitlement Control Message) - a message that controls access rights;

ECMG (Entitlement Control Message Generator) - ECM message generator;

EMM (Entitlement Management Message) - a message granting access rights;

EMMG (Entitlement Management Message Generator) - EMM message generator;

ES (Elementary Stream) - elementary stream of video data (sound data, special data) of digital broadcast television; MPEG (Motion Pictures Expert Group) - a group of video and audio data compression standards;

MUX (Multiplexer) - multiplexer;

PID (Packet Identifier) - packet type identifier;

SAS (Subscriber Authorization System) - a system for granting authority to the subscriber (subscriber authorization system);

SCR (SCR DVB Compliant Scrambler) - a scrambler that complies with DVB technology;

SMS (Subscriber Management System) - subscriber administration (management) system;

TS (Transport Stream) - transport data stream of digital broadcast television; TP;

Access Criteria (AC) - information required by the access control message generator (ECMG) to generate the access control message (ECM);

Multiplex (multiplex) - transport stream at the output of the transport multiplexer;

Multiplexer (multiplexer; MUX) - a device designed to combine several data streams of a digital television signal into a single stream with the addition of service bits;

Subscriber Management System (SMS) - a system for recording information about subscribers, containing a database about subscribers, about subscriber decoders, about services to which subscribers have subscribed, about settlements with subscribers and about accounting payments, received from subscribers;

Scrambler (scrambler; SCR) is a device designed to transform the structure of a digital telecommunication signal, without changing the symbol rate of this signal, in order to bring its properties closer to those of a random signal;

Subscriber Authorization System (SAS) - a system that provides organization, ordering and delivery of data for the generation of messages granting access rights (EMM) and ECM messages; AND

Control Word (CW) - a data object used for scrambling (a low-level operational key that carries out the scrambling and descrambling process. CW changes with a frequency of 0.5 to 10 s).

As follows from the diagrams shown in Fig. 1-4 example implementation, the system for providing virtual channels to the end user (virtual channel service) consists of functionally interconnected transmitting 1 (operator) and receiving 2 (client) sides, where the transmitting side includes a system for generating and transmitting the transport stream of the service for providing virtual channels, in the considered case of implementation, consisting of connected to each other and to the multiplexer by 3 communication lines, an electronic program program server 4 (EPG server) and a conditional access subsystem 5 CAS (CAS subsystem), including a conditional access server 6 CAS (CAS Server) and an encrypting device 7 (in particular, as shown in the diagram of Fig. 1, a scrambler), equipped with means for encrypting and providing access to the encrypted content of linear channels. In the virtual channel service system, of which the claimed solution is a part, a client device is used as the receiving side - a digital satellite receiver 8 (set-top box, STB), equipped with at least a tuner/demodulator (Tuner/Demodulator) (in illustrative not shown in the materials), receiving the input signal of the MPEG-2 transport stream and transmitting it after processing to the input of the cryptomodule (CAS module) (not shown in the illustrative materials), which is responsible for descrambling the incoming coded stream, the input of which is connected to the input of the main processor (CPU) (not shown in the illustrative materials), which processes the data and transmits the audio-video signal, presented to the end user by the user interface and channel content, to the audio-video output. According to the claimed solution, the EPG server input is connected to external control systems, in particular, control of algorithms preinstalled in the EPG server memory for implementing the claimed solution by entering the necessary data by the operator, and/or head equipment systems in automatic mode. In this case, one of the EPG server outputs is connected to the first input of the CAS subsystem, and the second is connected to one of the multiplexer inputs. The second input of the CAS subsystem is supplied audio/video content (content) of the satellite broadcasting system. As noted above, in the generalized implementation diagram of the claimed solution, presented in the diagram of Fig. 1, the AS Server and the scrambler are connected to each other via a feedback line and are equipped with outputs connected to the corresponding inputs of the multiplexer.

The functional connection between the transmitting and client parts of the virtual channel service provision system is provided by a data transmission channel, which uses a satellite signal (Transport Stream), MPEG-2 transport stream (ISO/IEC standard 13818-1, ETSI TS 102 154), generated by a multiplexer transmitting side and received by the client device.

The modules, subsystems, equipment and hardware or structural elements and devices included in the virtual channel service system and its component - the system for generating and transmitting the transport stream of the virtual channel service - are equipped with hardware, design and/or software and hardware that provide functionality specified elements of the virtual channel service system in accordance with the stated solution. The specified design and hardware means do not go beyond the generally accepted design solutions for the specified system elements. At the same time, their functionality, directly or indirectly, being in the constructive or functional unity of the system elements, is regulated by specified software and hardware algorithms, preinstalled in the memory of the programmable hardware of the satellite broadcasting system to the end user, controlling the hardware and design of the virtual channel service system.

In this case, the server of the electronic program of television programs EPG (EPG server; EPG server), as part of the transmitting side of the system for generating and transmitting the transport stream of the service for providing virtual channels, is a server equipped with a memory unit (not shown in the diagram), which initially stores the transmission schedule for all channels operator, and equipped with tools for generating a schedule of content events for linear broadcast channels, metadata and a schedule of virtual service channels. Moreover, the schedule of each of the virtual channels of the service is formed in the form of a composition of a sample of content events of linear broadcast channels, selected by criteria preset for each virtual channel and broadcast within the virtual channels of the service sequentially in time, setting for each sampling event the identifier of the corresponding virtual channel and the mark of the use of the event in its composition. To generate the specified selection of EPG events, the server provides the generation of metadata for virtual channels, including basic data: their name, position in the general list of channels, program schedule, as well as additional data, for example, logos, virtual channel icons and banners. At the same time, the EPG server also implements the formation and generation of service metadata and carousels for broadcasting metadata.

The CAS subsystem of the transmitting side of the system for generating and transmitting the transport stream of the service for providing virtual channels provides encoding and provision of access to the encoded content of linear broadcast channels (linear channels) and virtual channels of the service, based on the schedule of virtual channels. The CAS subsystem includes a CAS Server and a Scrambler, which provides encoding of the content of linear channels. In addition, the CAS subsystem is equipped with means for generating control words with encryption of their session keys, as well as ECM and EMM messages containing them, for each linear and virtual channel of the service system or their group, and the same content event broadcast by different channels is executed an encrypted common control word, encrypted with different session keys for each linear and virtual channel or their group.

The multiplexer (Multiplexer) of the transmitting part of the system for generating and transmitting the transport stream of the service for providing virtual channels is equipped with means of forming the transport stream by embedding into it at least the content of linear broadcast channels, a schedule of content events, and commands for accessing encrypted content. The multiplexer ensures the formation of a transport stream (Broadcast Stream) by embedding into the transport stream media content of linear broadcast channels received at the input from the broadcast operator, a service metadata file, additional metadata, commands for accessing encoded content, and additional service information. According to the claimed invention, the transport stream at the output of the multiplexer is preferably MPEG- 2 transport stream and includes at least: linear broadcast channels, the content of which is also used as part of virtual channels; basic and additional metadata of the virtual channel service; if necessary, Linkage descriptor; MPEG-2 transport stream service tables including: RMT program structure table; CAT conditional access table; NIT network information table; TDT date and time table; BAT table of program groups.

The receiving side of the claimed virtual channel service system, according to the presented example implementation, is equipped with a client device made in the form of a digital satellite receiver, equipped with at least a tuner/demodulator that receives the input MPEG-2 transport stream signal, a cryptomodule designed to enable decryption of the incoming encrypted transport stream. In one of the embodiments of the claimed invention, the cryptomodule is equipped with a sectional filter of commands for setting the rights of a virtual channel, a processor of the EMM type of messages corresponding to the virtual channel and the ability to send commands to set the rights and session keys of the virtual channel, as well as the main CPU processor that processes data, providing to the end user on audio-video output the content of linear broadcast channels and virtual service channels in the user interface module. In another embodiment, the main processor CPU of the client device is configured to provide the ability to decrypt the incoming encrypted transport stream, through a built-in security system, and perform data processing, providing the end user with audio-video output channel content in the user interface module, wherein the CPU is equipped with a sectional a command filter for setting the rights of a virtual channel, a handler of EMM type messages corresponding to a virtual channel and the ability to send a command to set the rights and session keys of a virtual channel. The receiving side of the virtual channel service system is not the subject of the stated solution and is considered in this example of feasibility solely to explain the essence of the stated solution and to achieve the stated technical result by using it. The process of forming and transmitting the transport stream of the service for providing virtual channels actually begins with the process of forming virtual channels of the service, according to the claimed invention, carried out through the sequential execution of the following stages of their formation, transmission and broadcast.

At the first stage of the formation of virtual channels of the service, on the EPG server, equipped with means for generating a schedule of events for the content of linear broadcast channels, in the user interface in a software-hardware manner, through an operator or in automatic mode, a directory of virtual channels is formed, containing at least basic data, including the name of the channel and the position number in the list of channels, as well as additional, but not mandatory, data for each of the channels, for example, a channel logo for displaying it in the user interface module of the client device as an identification feature of the channel, a banner for displaying during technology breaks, for example , intended for its use when there is no broadcast of a linear channel in the virtual channel schedule. The directory of virtual channels is created, stored and edited exclusively on the EPG server. Its adjustment from the client device is not available.

The formation of a selection of events that should be added to the schedule of the generated virtual channels can also be carried out in software and hardware, both manually and automatically. At the same time, as events (transmissions) as units of content of a linear as well as a virtual channel, for example, films, advertising blocks, talk shows, cartoons, TV series, sporting events, news, educational and/or educational programs can be accepted , static images, etc. As a scheduling unit, any event is characterized by the date and time of its start and end, as well as a set of metadata indicating the original broadcast channel in the system.

The operator manually generates a selection of virtual channel events in accordance with the selection of hardware and software images of events corresponding to the virtual channel topic specified by the operator, or, for example, based on the results of an analysis of content consumption. According to the provided selection of linear channel transmissions, via the web interface, for the corresponding event, a mark is set for the use of this event as part of a virtual channel and the identifier of a specific virtual channel to the schedule of which the event should be added. In this case, the same event can be marked for adding to the schedule of several scheduled virtual channels. In turn, the automatic formation of a selection does not require the direct participation of the operator; information about the programs is added to the metadata file automatically in software and hardware, based on the results of searching for events in the web interface according to preset criteria. The search is carried out according to the specified parameters in the appropriate form of the EPG server web interface. For example, specific linear channels, event genres, keywords, etc. can be used as parameters for creating a selection of events.

After completing the formation of the schedule on the EPG server, the generation of metadata is initiated by selecting the corresponding algorithm pre-installed in software and hardware in the user interface of the EPG server and based on data pre-installed automatically or specified manually by the operator. The EPG server is equipped with tools for generating, based on the specified algorithm, two types of metadata of virtual service channels: basic metadata and additional metadata, where

- the main metadata represents the schedule of each of the virtual channels with a directory of virtual channels, where the schedule for each of the virtual channels consists of events broadcast as part of linear broadcast channels, marked in a preset way when forming a selection of virtual channel events.

- additional metadata is graphical data, at least including a technological break banner installed in pauses between adjacent broadcasts of virtual channel events, and a channel logo, etc. additional information perceived in the form of a screensaver or a static image (logo).

In this case, the main metadata at least contains event parameters, including description, start and end times of the event, parameters of the linear broadcast channel in the SNT transport stream (Service ID, Network ID, Transport Stream ID), on which the virtual channel event is broadcast, identifier virtual channel, and virtual channel parameters, including name of the virtual channel, position in the list of channels, links to each of the additional metadata files with their binding to the virtual channel, for example, in the form of a “dvb:” URL (see ETSI TS 102 851), that is, links to a specific file in a separately broadcast service.

Technological interruptions in the broadcasting of a virtual channel can be caused, for example, due to the existing time difference between the end of one event (transmission) and the start of broadcasting of the next event (transmission), since these events may belong to different linear broadcast channels, or are spaced apart in time broadcast schedule of one linear channel. The diagram in Fig. 2 shows examples of creating a virtual channel schedule, including setting a technological break mark (Fig. 2a). As follows from the example presented in the diagram of Fig. 2a), event 1 broadcast on a linear channel from 13:00 to 14:00 of one day, event 2 broadcast on a linear channel from 14:30 to 15:00 can be added to the virtual channel schedule the same day. The time interval that occurs between events in the period from 14:00 to 14:30 is marked in the schedule with a technological break (Fig. 2a)). When generating the schedule, the suppression of events by time is also taken into account (Fig. 2a)). When events overlap, the event that starts earlier is added to the schedule. For example (Fig. 2, a)), for one virtual channel the operator marked the events of linear channels from 13:00 to 14:00, from 13:30 to 14:30, while the algorithm preinstalled on the EPG server for generating a schedule of virtual channels and their metadata will add an event from 13:00 to 14:00 to the schedule of this virtual channel. The next event that can be added to the schedule of this virtual channel must have an event start time only after the end of broadcasting of the first event. In any case, when generating a schedule of virtual channels, during the absence of display of events of linear channels of the generated sample of events for their broadcast within the virtual channel, the algorithm preinstalled in the memory of the EPG server adds a separate event to the schedule of the virtual channel, with the type of technological break. The event type is added by means of pre-installed software and hardware means for generating metadata and scheduling virtual channels of the EPG server, when generating a metadata file in the corresponding parameter, for example, as presented in the example implementation of the claimed inventions in Table 1. Moreover, as can be seen from the example presented in Table 1, for an event of the “technological break” type, the list of necessary parameters specified in the metadata file differs from the list of necessary parameters of events of linear channels broadcast as part of the service’s virtual channels.

A description of the metadata file information parameters and their content in the metadata file is given in the table below.

Table 1.

Description of virtual channel metadata file parameters

As a result of generation, the main metadata is a file in JSON format, the additional metadata is an archive containing all the necessary graphic data files. Below is an example of generating a metadata file.

When the virtual channel data changes on the EPG server, for example, when updating the schedule, changing banners, etc., the necessary data is re-generated and subsequently transmitted to the components of the transmitting side: to the CAS and to the input of the multiplexer.

The generated metadata is formed in a manner known from the prior art, using the appropriate preinstalled software and hardware of the EPG server, into streams and transmitted to the input of the multiplexing device. The file containing the main metadata of the virtual channel service is transmitted as a data carousel stream (ETSI TR 101 202). An archive containing additional metadata is formed and transmitted as an object carousel stream (ETSI TR 101 202). The carousel method is a mandatory method of broadcasting data in a transport stream to ensure that data is delivered to the client device, taking into account the cyclic repetition of data in the stream.

At the next stage, the generated virtual channel schedule is transferred from the EPG server to the conditional access subsystem C AS.

For subsequent descrambling of linear channels as part of virtual channels, using an algorithm preinstalled on the EPG server in hardware and software, the main metadata (generated schedule of virtual channels) is transmitted to the remote access subsystem, to the CAS server, simultaneously with the transmission of the main metadata to the input of the multiplexer. The main metadata, as stated earlier, necessarily contains the following information: channel parameters (including SNT parameters of linear channels used as part of the service’s virtual channels), date/time of the start and end of linear channel events.

Based on the received data and the audio-video content arriving at the second input to the remote access subsystem, the content is encrypted and the data of broadcast channels and content is generated in the CAS conditional access subsystem (FIG3) that complies with DVB-Simul crypt standards (ETSI TS 103 197), in accordance with DVB CSA (Digital Video Broadcasting Common Scrambling Algorithm) algorithm.

In general, the encryption/decryption (scrambling/descrambling) process is carried out as follows. An open (unencrypted) transport stream (TS) is supplied to the input of the encrypting device 14 (scrambler, SCR), which, in addition to additional information, contains audio and video content of linear satellite broadcast channels. The scrambler 14, using a control word generator (not shown in the diagrams of Fig. 3), made in hardware and software, generates control words (CW) used to encrypt the transport stream. The functional component of the CAS server 6 - the EMM message generator 13 (EMMG) (Fig. 3) transmits the generated session key (OrKey), used for encryption/decryption of the CW. The scrambler transmits the CW to the CAS server functional component, to the ECM message generator 12 (ECMG) (Fig. 3) for subsequent generation of an ECM message containing encrypted CW control words. In turn, the CW control words are encrypted using session keys OrKey for subsequent generation of an ECM message containing the encrypted CW control words. The content of the transport stream is encrypted using CW control words and adding ECM messages. Thus, the encryption of the same event broadcast by different channels is carried out with a common control word, encrypted with different session keys for each linear and virtual channel or their group, and the metadata files of the virtual channel service are transmitted to the input of the multiplexer. EMMG generates EMM messages containing service data, access rights information, and specialized commands. The generated EMM messages are also transmitted to the input of multiplexer 3, where they form a transport stream by embedding service metadata into the transport stream of the content of linear broadcast channels. As a result, at the output of the multiplexer, in the context of the conditional access subsystem, an encrypted transport stream is obtained containing ECM and EMM messages in accordance with the DVB standard (ETSI TS 102 470-1), which are transmitted to the input of the client device for receiving and decrypting the secure transport stream at the receiving part of the satellite system broadcasting subject to a valid subscription. Thus, CAS, together with the head equipment, allows you to control subscribers’ access to their services for the implementation of pay television services.

Thus, according to the claimed invention, to ensure access to encrypted content only within the virtual channel service, The above-mentioned CAS conditional access subsystem performs the following actions:

- processing the list of virtual channels and their schedules.

- generation and storage of a separate set of session keys for access to the encrypted content of virtual channels.

- encryption of CW control words with an additional session key of the virtual channel.

- generation and distribution of EMM with virtual channel session keys.

Restriction of access to content, both linear and virtual channels, can be carried out not only by the broadcast time frame of the event broadcast on these channels, but also by the availability of access rights to view the content, determined by the user’s subscription to the virtual channel service. To take this circumstance into account, according to the stated solution, the transmitting part of the CAS server additionally generates EMM messages with access control commands and session keys for technology packages of virtual channels, ensuring control of subscriber access to the content of the virtual channel service in modes in accordance with data on existing subscriptions received from the billing system.

However, it is also possible to implement another embodiment of the stated solution, for example, when implementing marketing campaigns, when free access is provided for subscribers who have authorized equipment and activation of the functionality of virtual channels according to the parameters of promotions carried out using virtual channels preset in the system.

Thus, the claimed solution makes it possible to provide, within the framework of a virtual channel formed on the transmitting side, without user participation, local access to selected events of a linear broadcast channel if there is a subscription or other authorized access to the virtual channel, regardless of the presence or absence of access rights to the linear channel or a group of linear channels whose events are included in the virtual channel.

After processing the received schedule, the EMM message generator generates a set of session keys for accessing events virtual channels, different from session keys for access to linear broadcast channels. The control words are additionally encrypted with the generated session keys of the virtual channel. Thus, the same content is scrambled (encrypted) using several session keys: one of which is used to descramble content outside the service, the other is used to descramble the same content when it is played back within the virtual channel service.

Next, the encrypted data stream for descrambling is transmitted from the CAS subsystem to the input of the multiplexer, where the transmission of EMM messages from the CAS server, necessary for descrambling the events specified in the schedule within the virtual channel, is compared with the schedule: distribution of rights in accordance with the beginning of events, command to suspend rights Access to an event on a given virtual channel occurs in accordance with the end of the event.

The multiplexer is configured to embed data received from the EPG server and subsystem C AS into the TS transport stream. For metadata received from the EPG server, the service broadcast parameters - SNT - are set manually or automatically in software and hardware, for example, through the CAS subsystem interface. For broadcasting metadata, a separate service is allocated as part of the transport stream: for the main metadata and for additional metadata, a separate package (PID) is allocated to simplify the search for the required metadata component.

Since, according to the claimed solution, the formation of a virtual channel does not require copying the content of a linear broadcast channel and/or any recording from individual events included in the virtual channel into the memory block of the hardware of the transmitting and/or receiving side, and the broadcast of virtual channel events is carried out by organization of limited access to a linear broadcast channel for the period of its broadcast and does not apply to access to a linear channel outside the framework of an event broadcast simultaneously via linear and virtual channels, broadcasting of metadata in one service, according to the considered example of implementation, is carried out only on one transponder, which allows the transponder to save capacity used for broadcasting metadata, To identify (discover) a service with metadata, in this case, service information is used with a link to the service with metadata, which is a Linkage descriptor (ETSI EN 300 468 VI .14.1). The Linkage descriptor is added in the graphical interface of the multiplexing device to the stream’s network information table - NIT (Network Information Table, ETSI EN 300 468). The location of the descriptor in the stream is determined by the fact that the NIT table on all transponders of the operator contains the same set of data.

Among the service information contained in the Linkage descriptor, there are metadata broadcast parameters (SNT), service identifier and metadata format version.

An example representation of the Linkage descriptor structure is given below in Table 2

table 2

The Linkage descriptor specifies the following parameters available for editing:

1. Transport Stream ID, Original Network ID, Service ID - metadata file broadcast parameters (SNT).

2. Data Bytes - a string of hexadecimal data containing:

1. signature (four bytes) - service identifier (used directly to match the descriptor with the service),

2. json_format_version - version of the metadata file format (for the ability to update the service without backward compatibility).

Using the Linkage descriptor allows you to create a virtual channel service without user feedback, which provides additional protection for content when it is possible to view it as part of virtual channels.

The transport stream generated in accordance with the claimed invention at the output of the MPEG-2 multiplexer contains at least: - linear channels, the audio-video content of which will be used as part of virtual channels;

- service with metadata of virtual channels (main and additional metadata);

- Linkage descriptor for service discovery with virtual channel metadata;

- MPEG-2 transport stream service tables (according to the EN 300 468 standard), among which are necessarily present:

- RMT (Program Map Table) - program structure table. Included in the stream for each TV program and contains the PID of the TV program components - video, sound, synchronization. In addition, the RMT contains conditional access system ECM messages if the program contains encrypted elementary streams.

- CAT (Condition Access Table) - conditional access table. Contains individual PIDs of all EMM messages.

- NIT (Network Information Table) - network information table. Contains parameters of the data transmission system.

- TDT (Time Data Table) - date and time table. It is a source of reliable time for the client device, allowing you to schedule virtual channels.

- BAT (Bouquet Association Table) - table of program groups. Contains information that allows the client device in this solution to find the corresponding operator channels and related service information.

As a result of the formation, according to the stated solution, of the transport stream and its transmission to the receiving side, the operation of the virtual channel service on the receiving side is carried out as follows.

Once selected by the user (subscriber) to view a virtual channel, for example, by selecting a channel in a list by pressing a button on the remote control, most of it consists of displaying the content of the selected virtual channel (automatic switching according to a schedule) with descrambling of the corresponding content.

When you select to view a virtual channel, the CPU STB automatically turns on the content according to the schedule by automatically switching to the current event of the linear channel according to the SNT parameters, if at the selected time of connection to the virtual channel, content is being broadcast on the linear channel, or displaying a banner received as part of additional metadata, if the current event is a technological break. Subsequent operation of the virtual channel service is carried out according to the received schedule: upon completion of the current event, it switches to the SNT of another linear channel if the next virtual channel event is broadcast on this linear channel, or displays a banner received as part of additional metadata if the next event is technological break.

After automatic switching (Fig. 4) to a specific linear channel as part of a virtual one, the main processor makes a request to the cryptomodule to descramble the corresponding content. The cryptomodule initiates access to the transport stream data stored on the smart card to decrypt the control word to descramble the content of the virtual channel, configures elementary streams for the descrambler based on the RMT (service Program Map Table) received from the main processor to receive ECM messages, installs control signals in the descrambler CW words derived from the transport stream. Decryption of the corresponding content after automatic switching to the linear broadcast channel broadcasting the content event as part of the virtual service channel, setting up the elementary streams of the transport stream for the descrambler in accordance with the information in the RMT service table for receiving ECM messages and installing control words in the descrambler is carried out by means of the main processor, designed to provide the ability to decrypt an incoming encrypted stream using a built-in security system.

Thus, the linear channel is descrambled for the duration of the event broadcast when it is played back within the virtual channel service, while the content of the linear channel outside the virtual channel service remains encrypted. To support this virtual channel model, CAS provides access only for specified TV programs in virtual channel operating mode. Wherein:

1. Access to virtual channel TV programs when viewing the source channel remains closed (in the absence of a valid subscription). That is, all TV programs when watching a regular channel remain unavailable if you do not have a subscription.

2. Subscriptions to source channels do not affect the list of TV programs available in the virtual channel. Only the TV shows specified in the channel schedule remain available in the virtual channel (regardless of the presence of subscriptions to the source channels).

3. Changing TV program settings via a virtual channel automatically affects the CAS access control logic:

1) When adding a TV program to a virtual channel, access is provided in accordance with the broadcast schedule of the TV program (for the duration of the broadcast in the stream). To do this, ECMG encrypts a CW copy of the broadcast channel using the session key of this virtual channel during the broadcast of the TV program in the virtual channel (see Fig. 4). As a result, STB subscribers with a valid subscription to this virtual channel have the technical ability to decrypt CW and open the channel during the broadcast of a TV program.

2) When a TV program is deleted from a virtual channel, access is blocked due to the fact that EMMG stops using the session key of the virtual channel when encrypting CW.

3) When changing the broadcast schedule of a TV program from a virtual channel, the availability time of the channel content is shifted in accordance with the new start/end time. This is also controlled by ECMG by using the session key of the virtual channel strictly in accordance with the current broadcast schedule of the virtual channel.

4. Support for access control of several virtual channels simultaneously is implemented with the following capabilities:

1) include the same broadcast channel in several virtual channels. 2) add several television programs broadcast at the same time (having overlap) to the virtual channel.

The claimed group of inventions allows:

1) Expand the list of channel packages without broadcasting multiple copies of channels (which are included in several channel packages).

2) Flexibly and safely limit access to individual TV programs (according to the conditions of copyright holders, rules for distributing content in services, and other restrictions).

3) Provide access to television programs only within a virtual channel. CAS provides access to TV shows within broadcast channels only if you have a valid subscription to the corresponding channel packages.

4) Manage access to virtual channels through subscriptions from the billing system, and in bulk to all authorized devices when activating access to the virtual channel function (all or only specified devices).

The modules, blocks and other components have been described above in terms of their features and the functions they provide, together with optional and preferred features. With the information provided and the characteristics and description given, the practical implementation of these features and specific implementation details can be determined by the developer. For example, certain modules could be implemented using software, and some or all components could be implemented using specialized hardware.

The modules and components described above are merely illustrative examples. The invention can be implemented in a variety of ways and, in particular, some components can be integrated with others that perform similar functions, or some components can be omitted in simplified implementations. Hardware and software implementations of each of the described functions can be combined in any combination, both between several components and for each individual component.

It is understood that the functions performed by hardware, computer software and the like are performed on electrical and similar signals or using them. Software implementations may be stored in ROM or may be hardcoded into flash memory.

It is clear that the present invention has been described above using purely illustrative examples of possible embodiments, and various changes in implementation details are possible without departing from the scope of the present invention.

Each of the features disclosed in the description and (where appropriate) in the claims and drawings may be implemented either independently or in any suitable combination.

The claimed solution of the group of inventions provides a simple solution for expanding the operational capabilities of both the system for forming and transmitting the transport stream of the service providing virtual channels, and the satellite broadcasting system as a whole, by expanding the capabilities of broadcasting content without increasing the transponder capacity and memory capacity of the transmitting and client parts with a simultaneous increase level of content protection by forming virtual channels, the broadcast of content of which does not require prior recording of the content of linear broadcast channels, by creating a broadcast schedule for a virtual channel by forming a selection of content events of linear broadcast channels, selected according to criteria preset for each virtual channel and broadcast within the virtual channels service sequentially in time and ensuring broadcasting of virtual channel content by securely switching to linear channel content broadcast in accordance with the virtual channel schedule, broadcast at a specified time.

Claims

CLAIM

1. A system for generating and transmitting a transport stream of a service for providing virtual channels, including at least those formed on the transmitting side, connected to each other and to a multiplexer by communication lines, an EPG server for an electronic program of television programs, equipped with means for generating a schedule of events for the content of linear broadcast channels, and a subsystem conditional access CAS, including an encrypting device equipped with means of encryption and access control to the encrypted content of linear channels, and the multiplexer is equipped with at least means of generating a transport stream of broadcasting linear channels, characterized in that

- and the CAS subsystem is equipped with means for generating control words with encryption of their session keys, as well as ECM and EMM messages containing them, for each linear and virtual channel of the service or their group, with setting access rights to broadcast the linear channel event specified in the schedule as part of the virtual channel and its suspension at the end of the event.

2. The system according to claim 1, characterized in that the EPG server is equipped with means for generating two types of metadata of virtual service channels: basic metadata and additional metadata, where

- the main metadata represents the schedule of each of the virtual channels with a directory of virtual channels, where the schedule consists of events broadcast as part of linear broadcast channels, marked in a preset way in the system when forming a selection of virtual channel events.

3. The system according to claim 2, characterized in that the main metadata of the virtual channels contains event parameters, including description, start and end times of the event, parameters of the linear broadcast channel in the SNT transport stream, virtual channel identifier, and virtual channel parameters, including the name of the virtual channel , position in the list of channels, links to each of the additional metadata files with reference to the virtual channel.

4. The system according to claim 3, characterized in that the main metadata of the virtual channel service is generated for transmission in the form of a data carousel stream, and additional metadata in the form of an object carousel stream.

5. The system according to claim 4, characterized in that in the transport stream the main metadata of the virtual channels of the service is made in the form of a file in JSON format, additional metadata is in the form of an archive file containing graphic data files.

6. The system according to claim 1, characterized in that the CAS conditional access subsystem is equipped with content encryption means so that the same broadcast event is encrypted with a common control word, which in turn is additionally encrypted with different session keys for each linear and virtual channel or their groups.

7. The system according to claim 6, characterized in that the CAS conditional access subsystem is equipped with content encryption tools in accordance with the DVB CSA algorithm.

8. The system according to claim 1, characterized in that the metadata of virtual channels is generated with the possibility of broadcasting in one service on one transponder, and is equipped with service information with a link to the service with metadata of virtual channels with the ability to detect the service with metadata in the transport stream.

9. The system according to claim 8, characterized in that the service information is equipped with a Linkage descriptor added to the network information table of the NIT stream, making it possible to provide virtual channel service to the end user without a user feedback channel.

10. The system according to claim 9, characterized in that the service information of the Linkage descriptor includes at least: parameters for broadcasting SNT virtual channel metadata, a service identifier with virtual channel metadata, and a version of the virtual channel metadata format.

11. The system according to claim 1, characterized in that the transport stream at the output of the multiplexer is an MPEG-2 transport stream and includes at least: linear broadcast channels, the content of which is also used as part of virtual channels; basic and additional metadata of the virtual channel service; Linkage handle; MPEG-2 transport stream service tables including: RMT program structure table; CAT conditional access table; NIT network information table; TDT date and time table; BAT table of program groups.

12. A method for generating and transmitting a transport stream of a virtual channel service, including sequentially performed stages, at which at least:

- form, according to preset criteria on the EPG server of the transmitting party, a directory of virtual service channels containing at least the name of the channels and their position number in the list of broadcast channels, and a schedule of events of virtual service channels by arranging a selection of content events of linear broadcast channels broadcast within virtual channels of the service sequentially in time and simultaneously with the corresponding broadcast of the linear channel event, setting for each sampling event the identifier of the corresponding virtual channel and marking the use of the event in its composition, with the subsequent generation of metadata for each virtual channel.

- receive and encrypt control words generated by the scrambler of the conditional access subsystem, generate session keys and ECM and EMM messages of broadcast channels and virtual channels containing them service system, and the encryption of the same event broadcast as part of the linear and virtual channels is carried out by a common control word additionally encrypted with different session keys for each linear and virtual channel or their group with the establishment of access rights to broadcast the linear channel event specified in the schedule as part of the virtual channel and its suspension at the end of the event, and transmit the metadata files of the virtual channel service to the input of the multiplexer, where they form a transport stream by embedding the service metadata into the transport stream of the content of linear broadcast channels and transmit it to the input of the client device.

13 The method according to claim 12, characterized in that at the stage of forming the metadata of the virtual channels of the service, the main and additional metadata are formed, where the main metadata of the virtual channels of the service represent the schedule of each of the virtual channels with a directory of virtual channels, and the additional metadata are graphic data, at least including a technology break banner, installed in pauses between adjacent broadcasts of virtual channel events, and a channel logo.

14. The method according to claim 13, characterized in that on the EPG server the main and additional metadata of the virtual channels of the service are formed into streams, where the main metadata of the virtual channel service is formed in the form of a data carousel stream, and additional metadata in the form of an object carousel stream.

15 The method according to claim 12, characterized in that the transmitting part of the CAS server additionally generates, stores, uses and automatically updates on a schedule session keys of CAS technology packages used to control access to broadcast events of linear channels through a virtual channel.

16. The method according to claim 12, characterized in that the transmitting part of the CAS server additionally generates EMM messages with access control commands and session keys for technology packages of virtual channels, ensuring control of subscriber access to content virtual channel service in modes in accordance with data on existing subscriptions received from the billing system and/or free access for subscribers who have authorized equipment and activate the functionality of virtual channels according to parameters preset in the system.

17. Method according to i. 12, characterized in that when forming an MPEG-2 transport stream using a multiplexer, additional service information is built into the transport stream, which is subsequently transmitted to the input of the client device, which is a Linkage descriptor in the network information table (NIT), ensuring dynamic detection by the client device of metadata of the virtual channel service in the transport stream, and on the client device discovering the metadata service in the transport stream through said Linkage descriptor without a user feedback channel.

18. The method according to any of paragraphs 12-17, characterized in that when generating a schedule of virtual channels of the EPG service by the server, when sampling events for a virtual channel broadcast by different linear broadcast channels intersect in time, an event with an earlier broadcast time is added to the schedule, and When events of linear broadcast channels are not displayed, a technological event preset in the service system is added to the virtual channel schedule.