RU2181929C2 - Extraction of data sections from translated data flow - Google Patents

Abstract

FIELD: television engineering; video and audio data storage. SUBSTANCE: proposed method provides for saving at least one of plurality of MPEG sections of MPEG data flow being translated; MPEG section has at least one MPEG-section flag. MPEG data flow is received and this single MPEG section is filtered off MPEG data flow in compliance with at least one MPEG section flag. Then MPEG section is saved. EFFECT: enhanced flexibility in handling users' system. 20 cl, 22 dwg

Description

 The invention relates to a device and method for storing one or more sections of a broadcast data stream, such as an MPEG bit stream, containing, in addition to data sections, television video and audio data.

 The advent of digital data transmission systems intended primarily for television broadcasting signals, in particular, but not exclusively satellite television systems, has opened the possibility of using such systems for other purposes. One of them is providing the user with an interactive mode of operation.

 One of the ways to ensure it is to run the application in the receiver / decoder, with which a television signal is received. The code for this application could be permanently stored in the receiver / decoder. However, this would be a limiting factor. Preferably, the receiver / decoder should be able to download code for the desired application. Thus, greater flexibility can be provided and the application can be updated if necessary without any user intervention.

 In computer systems, in particular systems where a computer system is part of some larger system, such as a receiver / decoder for a digital television or radio system, the memory size is often limited. This means that the memory must be organized in such a way that the use of the memory space by the various functions requested by the system is minimized. In addition, it may also be necessary to minimize the time required to access at least some parts of the memory.

 Accordingly, the present invention relates especially, but not exclusively, to loading into the receiver / decoder only the data that is needed specifically for a given application.

In a first aspect of the present invention, there is provided a method of storing at least one of a plurality of sections of a broadcast data stream, said one section having at least one section characteristic, wherein said method comprises the following operations:
receiving a data stream;
filtering off said one section of said data stream in accordance with at least one said section attribute; and
preservation of said one section.

 The filtering operation allows you to load into the receiver / decoder memory only those sections that are necessary for this application.

In a preferred implementation, the filtering operation includes the following operations:
specifying at least one filtering criterion, each feature containing a filtering criterion and a value for this filtering criterion;
comparing one or each sign of the section with the corresponding sign of filtering and
filtering said one section from said data stream when each section characteristic corresponds to a corresponding filtering attribute.

 In a second aspect of the present invention, there is provided a method for storing multiple sections of a broadcast data stream using the method described above, each section being stored in a corresponding memory location.

Preferably, the method further comprises the following operations:
setting at least one data filtering attribute, each data filtering attribute contains a filtering criterion and a value for this data filtering criterion;
comparing the data stored in each saved section with the corresponding sign of data filtering and
permission to replace said stored section in said memory when said data stored in this stored section does not correspond to a corresponding data filtering attribute.

 Preferably, the method further comprises the step of supplying the section identification signal to the application when said data stored in said stored section corresponds to said corresponding data filtering attribute.

 Preferably, the section identification signal comprises a storage address of said one section.

In a third aspect of the present invention, there is provided a method of storing a group of sections in accordance with the method described above, wherein said sections are cyclically broadcast in said data stream, and each group comprises a first section and a last section; said method comprises operations:
save the first section;
sequentially loading sections broadcast sequentially immediately after said first section, each section is sequentially stored in the corresponding memory section until said last section is loaded or a predetermined number of sections are saved.

In a fourth aspect of the present invention, there is provided a method of storing a group of sections in accordance with the method described above, wherein said sections are cyclically broadcast in said data stream, and each group comprises a first section and a last section; said method comprises operations:
save the first section;
subsequent loading of sections broadcast sequentially immediately after the first section, each section is sequentially stored in the corresponding section of memory until either the last section is loaded or a predetermined number of sections is saved, after which the sections stored in the sections of memory are sequentially overwritten subsequently loaded sections until the last section is loaded; and
storing said last section in said memory.

In a fifth aspect of the present invention, there is provided a method for storing a group of sections cyclically broadcast in said data stream, and said group comprising a first section and a last section; said method comprises operations:
receiving a data stream;
loading the first section and storing it in memory;
consecutively loading sections broadcast sequentially immediately after said first section, each section is sequentially stored in a corresponding memory section until said last section is loaded or a predetermined number of sections are stored in said memory.

In a sixth aspect of the present invention, there is provided a method for storing a group of sections cyclically broadcast in said data stream, said group comprising a first section and a last section, said method comprising the steps of:
receiving a data stream;
loading the first section;
sequentially loading sections transmitted sequentially immediately after said first section, each section is sequentially stored in the corresponding memory section until either the last section is loaded or a predetermined number of sections is saved, after which the sections stored in the memory sections are sequentially overwritten subsequently loaded sections until the last section is loaded; and
storing said last section in said memory.

 Due to the third through sixth aspects of the present invention described above, only the necessary sections from the group of sections are stored in the memory of the receiver / decoder. For example, when viewing a list of, say, three television programs scheduled for broadcast at a specific time, using the third and fifth aspects, only the first four sections of the group are loaded from the data stream, allowing the end user to quickly view the list from top to bottom, starting from the first program specified at that time. Using the fourth and sixth aspects, only the last four sections of the group are loaded from the data stream, allowing the end user to quickly view the list from the bottom up, starting with the last program indicated at that time, and minimizing the amount of receiver / decoder memory.

In a seventh aspect of the present invention, there is provided a device for storing at least one of a plurality of sections of a broadcast data stream, said one section having at least one section characteristic, comprising:
means for receiving a data stream;
means for filtering said one section from said data stream in accordance with at least one said attribute of the section and
means for storing said one section.

Preferably, said filtering means comprises:
means for setting at least one filtering criterion, each feature containing a filtering criterion and a value for this filtering criterion;
means for comparing each feature of the section with the corresponding feature of filtering and
means for filtering said one section from said data stream when each section characteristic corresponds to a corresponding filtering attribute.

 In an eighth aspect of the present invention, there is provided a device, as described above, for loading a plurality of such sections, and said storage means comprises a plurality of memory sections for storing corresponding sections.

Preferably, the device further comprises:
means for setting at least one data filtering attribute, each data filtering attribute contains a filtering criterion and a value for this data filtering criterion;
means for comparing each feature of the section with the corresponding feature of filtering data and
means for permitting replacement of said stored section in said memory when said data residing in this stored section does not correspond to a corresponding data filtering attribute.

The device may also contain:
means for supplying a section identification signal to the application when said data in said stored section corresponds to said corresponding data filtering attribute.

 The method or device described above can be applied with a data stream in the form of an MPEG bit stream, which contains, in addition to the sections mentioned, television video and audio data.

Preferred characteristics of the invention will be described below, by way of example only, with reference to the accompanying figures, in which:
in FIG. 1 shows the general architecture of a digital television system according to a preferred embodiment of the present invention;
figure 2 shows the architecture of an interactive system in a digital television system;
FIG. 3 illustrates the location of files in a module loaded into a receiver / decoder;
figure 4 shows the structure of the section;
in FIG. 5 shows the location of memory volumes in the memory of an interactive receiver / decoder;
6 schematically shows the interfaces of the receiver / decoder;
in FIG. 7 shows receiver / decoder software architecture;
in FIG. 8 shows a receiver system architecture for loading sections from an MPEG data stream;
in FIG. 9 shows the byte structure in a section used by a hardware prefilter;
in FIG. 10 shows an example of an array of a hardware filter mask and an array of values of a hardware filter;
in FIG. 11 shows the arrangement of bytes in a section that is used by a software filter;
12 shows an example of loading a table;
in Fig.13 shows an example of the location of the sections in the group of sections;
Fig. 14 shows an example of loading a group of sections in a follow-up mode;
on Fig shows an example of loading a group of sections in the preceding mode;
Fig.16 shows the placement of fields in the descriptor of the group of sections;
on Fig shows the placement of the fields in the descriptor of the section table.

 The general structure of a digital television broadcasting and receiving system 1000 according to this invention is shown in FIG. The invention includes the most common digital television system 2000, which uses the well-known MPEG-2 compression system to transmit compressed digital signals. In more detail, the MPEG-2 compression device 2002 in the broadcast center receives a stream of digital signals (typically a stream of video signals). The compression device 2002 is connected to the multiplexer and scrambler 2004 using the channel 2006. The multiplexer 2004 receives many input signals, collects one or more carrier streams and transmits the compressed digital signals to the broadcast center transmitter 2008 through the channel 2010, the type of which, of course, may be different. including telecommunication channels. The transmitter 2008 transmits electromagnetic signals via the ground-satellite channel 2012 to the satellite repeater 2014, where they are processed electronically and broadcast via the virtual satellite-to-ground channel 2016 to the ground receiver 2018, usually in the form of a plate, owned by the end user or rented them. The signals received by the receiver 2018 are transmitted to a combined receiver / decoder 2020 owned or rented by the end user and connected to the end user television 2022. The receiver / decoder 2020 decodes the compressed MPEG-2 signal into a television signal for the television 2022.

 The conditional access system 3000 is connected to the multiplexer 2004 and the receiver / decoder 2020 and is located partially in the broadcast center and partially in the decoder. It allows the end user to access digital TV broadcasts from one or more broadcast operators. A smart card can be installed in the receiver / decoder 2020, which can decode messages related to commercial offers (one or more television programs sold by the broadcast operator). Using a decoder and a smart card, a user can buy transmissions in subscription or pay-per-view (PPV) mode.

 Interactive system 4000, also connected to multiplexer 2004 and receiver / decoder 2020 and also located partially in the broadcast center and partially in the decoder, allows the end user to interact with various applications through the modem return channel 4002.

 In FIG. 2 shows the general structure of a television interactive system 4000 of a digital television system 1000 in accordance with the present invention.

 For example, the 4000 interactive system allows the end user to purchase products from on-screen catalogs, view local news and weather maps on demand, and play games using their TV.

The 4000 interactive system contains four main elements:
- 4004 development tool in the broadcast center or elsewhere, allowing the broadcast operator to create, develop, debug, and test applications;
- an application and data server 4006 in the broadcast center, connected to the development tool 4004, to enable the broadcast operator to prepare, authenticate and format applications and data for sending to the 2004 multiplexer and scrambler for insertion into the MPEG-2 carrier stream (usually in private section) to be broadcast to the end user;
- a virtual machine containing a real-time subsystem (RTE-Real Time Engine) 4008, which is an executable code installed in the receiver / decoder 2020, owned or rented by the end user, to enable the end user to accept, authenticate, deploy and download applications in the working memory of the decoder 2020 for execution; subsystem 4008 also runs general purpose resident applications; Subsystem 4008 is independent of hardware and operating system and
a reverse modem channel 4002 between the receiver / decoder 2020 and the application and data server 4006 for supplying signals indicating to the server 4006 to insert data and applications into the MPEG-2 carrying stream at the request of the end user.

 An interactive television system uses the so-called "applications" that control the operation of the receiver / decoder and various devices included in its composition. Applications are presented in the 4008 subsystem as the so-called "resource files". A “module” is a collection of resource and data files. Several modules can be used to form one application. The "memory volume" of the receiver / decoder is the storage space for the modules. To load modules use the "interfaces". Modules can be loaded into the receiver / decoder 2020 from the MPEG-2 carrier stream.

 The concepts mentioned in the previous paragraph will be described in more detail below.

 For this description, an application is a piece of computer code for controlling the high-level operations of the receiver / decoder 2020. For example, when the end user positions the focus of the remote control device 2026 (shown in detail in FIG. 4) on the button object visible on the TV screen 2022 and presses confirmation key, the sequence of instructions corresponding to this button is executed.

 An interactive application provides a menu and executes commands at the appropriate request of the end user and provides data in accordance with the purpose of this application. Applications can be either resident applications, that is, stored in the ROM (either in FLASH memory or other non-volatile memory) of the receiver / decoder 2020, or transmitted by broadcast and loaded into the RAM (or FLASH) of the decoder 2020.

Examples of applications are:
- Initialization application. The receiver / decoder 2020 is equipped with a resident initialization application, which is an adaptable set of modules (this term is explained in more detail below) and allows the receiver / decoder 2020 to be directly ready to work in the MPEG-2 environment. This application provides basic functions that can be modified by the broadcast operator if necessary. It also provides an interface between resident applications and downloadable applications.

 - Launch application. The launch application allows any application, either downloadable or resident, to be executed in the receiver / decoder 2020. This application acts as a bootstrap program that runs when a service arrives in order to launch the application. The launch application is loaded into RAM and, therefore, can be easily updated. It can be configured in such a way that interactive applications available on different channels can be selected and executed either immediately after downloading or after preloading. In the case of pre-loading, the application is loaded into memory 2024 and activated by the launch application as necessary.

 - Program Guide. Program Guide is an online application that provides complete program information. For example, it may contain information, say, on a weekly television program, provided by each channel from a package (“bouquet”) of digital television channels. By pressing the key of the remote control device 2026, the end user gains access to the secondary screen, which overlaps with the transmission that is currently being displayed on the TV screen 2022. This additional screen is a viewer that provides information on the current and subsequent broadcasts of each channel of the bouquet digital tv. By pressing another key of the remote control device 2026, the end user gains access to the application, which displays information on the program guide for the week. The end user can also search and sort programs by simple and individual criteria. The end user can also access directly the selected channel.

 - PPV application (PPV-Pay Per View, payment is made for each transmission watched). PPV application is an interactive service available on each PPV channel of a digital TV bouquet with a conditional access system of 3000. An end user can access the specified application using a TV menu or channel browser. In addition, this application starts automatically as soon as PPV transmission is detected on the PPV channel. Then the end user can buy the current program either using his daughter smart card 3020, or using the communication server 3022 (using a modem, phone and DTMF codes (tone dialing codes), MINITEL or other similar ways). This application can be resident in the ROM of the receiver / decoder 2020 or loaded into the RAM of the receiver / decoder 2020.

 - PC download application. The end user can, upon request, download computer software using the download application on a PC.

 - Magazine viewer application. The magazine viewing application provides periodic broadcasting of video images, providing the user with the ability to navigate using buttons on the screen.

 - Quiz application. The quiz application is preferably synchronized with the broadcast quiz program. For example, several possible answers are displayed on the TV screen 2022 and the user can select the answer using the remote control device 2026. The quiz application can inform the user whether his answer is correct or not, and can count the points scored by the user.

 - The application of distance shopping. In one example of a remote shopping application, offers of goods for sale are transmitted to the receiver / decoder 2020 and then displayed on the TV screen 2022. Using the remote control device, the user can select a specific product for purchase. An order for this product is transferred via the reverse modem channel 4002 to the application and data server 4006 or to a separate sales system whose phone number has been downloaded to the receiver / decoder, it is possible to debit the credit card account that is installed in one of the 4036 card reader devices / decoder 2020.

 - The application of remote banking services. In one example of a remote banking service application, a user installs a bank card in one of the 4036 card reader devices of the receiver / decoder 2020. The receiver / decoder 2020 calls the user’s bank using a phone number recorded in the user's bank card or stored in the receiver / decoder, and then the application provides a set of tools that can be selected using the remote control device 2026, for example, to download an account status report via a telephone line, transfer money from one account to another, requesting a checkbook, etc.

 - The application of the Internet browser. In one example of an Internet browser application, user instructions, such as a request to view a web page having a specific URL, are entered using the remote control device 2026, and they are sent via the reverse modem channel 4002 to the application and data server 4006. The corresponding web page then included in the data transmitted from the broadcast center received by the receiver / decoder 2020 via the ground-satellite channel 2012, the repeater 2014 and the satellite-ground channel 2016, and then displayed on the TV screen 2022.

 Applications are stored in the memory of the receiver / decoder 2020 and are presented as resource files. Resource files are understood as graphic library descriptor library files, variable block library files, command sequence files, application files, and data files.

 Graphic object description library files describe screens, human-machine interface of the application. Variable block library files describe the data structures that an application operates on. Command sequence files describe the functional actions performed by the application. Application files provide entry points for applications.

 Applications compiled in this way can use data files such as icon library files, image files, font files, color table files, and ASCII text files. An interactive application can also receive live data by using inputs and / or outputs.

 Subsystem 4008 loads into its memory only those resource files that it needs at this time. These resource files are read from library files for descriptions of graphic objects, files of command sequences and application files; library files of variable blocks are written into memory after calling the module loading procedure and remain there until a special call to the module unloading procedure is made.

With reference to FIG. 3, a module 4010, such as a remote shopping module, is a collection of resource and data files containing the following:
one application file 4012;
an indefinite number of files of libraries of descriptions of graphic objects 4014;
an indefinite number of variable block library files 4016;
an indefinite number of command sequence files 4018; and
if necessary, 4020 data files, such as icon library files, image files, font files, color table files, and ASCII text files.

 In the MPEG data stream, each module forms a group of MPEG tables. Each MPEG table can be formatted as a number of sections. In an MPEG data stream, each section is up to 4 kB in size. For data transmitted, for example, through a serial or parallel port, the modules are also divided into tables and sections, and the size of the section varies depending on the transmission medium.

 Modules are transmitted in an MPEG data stream in the form of data packets typically 188 bytes in size, in data streams of the appropriate type, for example video streams, audio streams and teletext data streams. Each packet is preceded by a 13-bit packet identifier (PID), one PID for each packet transmitted in the MPEG data stream. The program distribution table (PMT - Program Map File) contains a list of different data streams and determines the contents of each data stream according to the corresponding PID. Thanks to the PID, the device can learn about the presence of applications in the data stream, the specified PID is identified using PMT.

As shown in FIG. 4, each section 4300 typically contains the following fields:
a table identifier (TID) 4302, typically 1 byte in size, located at the beginning of section 4300;
section size identifier 4304, typically 2 bytes in size;
section number (SN) 4306 (for example, 1) for this section in the table; SN usually has a size of 1 byte;
total number of sections (LSN) 4308 (for example, 3) in the table; LSN usually has a size of 1 byte;
TID 4310 extension, usually 2 bytes in size;
private data 4312 and
CRC 4314 section 4300. The purpose of CRC 4314 is to check all bytes of section 4300; if CRC 4314 matches all the previous data, then the section is received by the receiver / decoder 2020. Similarly, private data field 4312 may contain an MD5 signature at the end of the field, calculated based on the entire previous contents of this field 4312.

 As for the data received via the serial or parallel interfaces, the section fields may be somewhat different; usually sections received through any of the above interfaces contain a reduced amount of data in the fields from 4302 to 4310 and do not contain CRC 4314.

 For each module / table, all the sections that make up this table have the same TID 4302 and the same TID 4310 extension. For each application, all the tables that make up this application have the same TID, but different corresponding TID extensions.

 To obtain module 4010, for example, from the MPEG bitstream, the PID of both the module and the module catalog is required. This directory simply lists the 4010 modules that can be loaded from the carrier signal. Once this directory is loaded, the application is able to load one or more 4010 modules.

 The idea of using 4010 modules along with the idea of loading small pieces of code makes it easy to build applications. They can be loaded into the flash memory of the decoder 2020 as resident software or broadcast with the aim of loading into the RAM of the decoder 2020 only if the user needs them.

 The memory volume is the memory region for modules 4010. Such memory regions are located in the memory 2024 of the receiver / decoder 2020. As shown in FIG. 5, the memory 2024 is usually divided into the RAM 4022, the flash memory 4024, and the ROM volume 4026. Memory can be further divided into memory volumes associated with various interfaces through which the modules are loaded into the receiver / decoder 2020, for example, an MPEG volume for storing the modules loaded from the MPEG bitstream, and a serial volume for storing the modules received through the serial int interface.

 The volume of RAM, in turn, is divided into a zone intended for embedded programs (firmware), the workspace for the 4008 subsystem and buffers. Both applications and the subsystem itself can access flash memory and other non-volatile memory using the device manager.

 Each volume contains a list of modules 4010, each module 4010 contains a list of files 4012, 4014, 4016, 4018, 4020. There may be two files with the same name, but located in different modules. For example, one version of an application is usually stored in ROM volume 4026, and for the purpose of replacing it, subsequent versions are downloaded in flash volume 4024. The contents of files can be compressed in LZW format, however, since decompressing files takes a certain amount of time, files can be received uncompressed format.

 The physical interfaces of the receiver / decoder 2020 are used to download the data. As shown in FIG. 6, the receiver / decoder 2020 contains, for example, six loading means: an MPEG 4028 stream tuner, a serial interface 4030, a parallel interface 4032, a modem 4034, and two card readers 4036.

 With multiple sources of applications and many manufacturers of receivers / decoders 2020, it is important that the application work the same in each receiver / decoder and that each receiver / decoder runs any application equally and correctly. As shown in FIG. 7, the receiver / decoder 2020 includes a real-time microprocessor-controlled subsystem 4008 and a common application programming interface 4054. They are installed in each receiver / decoder 2020, so that all receivers / decoders 2020 are the same in terms of application .

 In FIG. 7 illustrates receiver / decoder 2020 architecture for executing 4056 applications. Virtual machine 4007 runs 4056 applications, which include 4056 'applications directly associated with the virtual machine, or 4056 "applications downloaded to receiver / decoder 2020, for example, from an MPEG data stream The 4008 real-time subsystem also displays graphics and text, calls up devices to take any action, receives "events" and uses the functions of the 4058 library for special calculations.

 As shown in FIG. 7, from an application point of view, the function of the decoder 2000 is represented as a device 4060. There may also be functions of the receiver / decoder 2000 that cannot be “seen” by applications.

 The device 4060 comprises a logic device unit, which may correspond to component 4066 or physical interface 4064 of hardware 4066. Such devices are referred to as “low level devices” 4068. The output of such device 4068 may be connected to at least one driver of device 4070 for converting logical signals generated by device 4068 to signals necessary, for example, to control hardware interface 4064. Alternatively, device 4068 can itself control a component or interface receiver / decoder 2020, that is, the output of the device can be connected directly to hardware 4066.

 Examples of low-level devices 4068 are described below.

 The LCARD device allows the program to exchange information with a smart card located in one 4036 card reader, and the RCARD device allows the program to exchange information with a smart card located in another 4036 card reader. For example, these devices allow the program to read the card status, read card history and send map input messages. The mentioned devices also inform the program about installing the card in the reader, about removing the card from the reader and reinstalling the card, if not requested by the program. LCARD and RCARD devices are compliant with the standard used to execute the card. Commonly used standard is07816.

 The SCTV device allows the program to check and configure the scart connector to the TV 2022. For example, this device allows the program to request information about the sound characteristics of the scart connector, perform sound cancellation ("MUTE"), and dynamically program color levels (RGB).

 The TUNER device (tuner) allows the program to use the 4028 tuner. For example, this device allows the program to scan from either the minimum frequency or the current tuner frequency, read the tuner parameters and program the tuner.

 The SERIAL device (serial port) allows the program to exchange information with the equipment through the serial channel, and the PARALLEL device (parallel port) allows the program to exchange information with the equipment through the parallel channel. For example, these devices allow a program to send a message through an appropriate channel and inform the program about receiving a message through this channel.

 The MODEM device (modem) allows the receiver / decoder to exchange information with the data server through an integrated half duplex modem that supports V32. The MODEM device requests dialing, sending a message to the data server and disconnecting the modem, and also signals the receipt of a message, the detection of errors and the loss or detection of a carrier signal.

 Remote devices working remotely can be any local devices, provided that the port and protocol are specified.

 In addition to the “low level devices”, the receiver / decoder 2020 may also include “high level devices” 4072 that control the operation of the receiver / decoder 2020.

 Regarding the sections loaded from the MPEG data stream, a 4072 device called an “MLOAD device” allows the application to load an MPEG section, a full MPEG table, or a group of MPEG sections that meet the criteria for hardware and software filtering.

 As shown in FIG. 8, the electromagnetic signal is received by the receiver 2018 and transmitted to the MPEG tuner 4028. The tuner usually scans the frequency range, stopping only when it detects a carrier frequency in this range. The signals detected in this way are transmitted to a demodulator 4500, which demodulates the signals and transfers them to the demultiplexer 4502. The demultiplexer 4502 is connected to the MPEG 4504 chip, which, in turn, is connected to the TV 2022. The demultiplexer 4502 is also connected to a hardware filter 4506, which usually has up to 32 outputs connected to the volume of the 4022 receiver / decoder random access memory 2020.

 The electromagnetic signals received by the demultiplexer 4502 comprise several data packet streams, which typically include a video packet stream, an audio packet stream, a teletext packet stream, and a subtitle packet stream to provide services to a broadcast operator. These data packets are demultiplexed by a demultiplexer 4502 and transmitted to an MPEG 4504 chip for decoding into signals for a television 2022.

 Application-related data packets are transmitted to hardware filter 4506. As shown in FIG. 9, a hardware filter, or prefilter, 4506 uses one or more of the usually 8 bytes of section 4508 of the data stream, usually byte at offset 0 (4510) and bytes at offsets 3 through 9 (4512), to filter out sections from the stream data. These bytes contain TID 4302, section number 4306, last section number 4308, and TID extension 4310 of MPEG 4508 section.

 To determine the characteristics of a hardware prefilter, the application indicates which bits of section 4508 should be taken into account and the expected value of each selected bit. Accordingly, the hardware prefilter 4506 contains an array of filter masks 4514 and an array of filter values 4516, respectively, an example of each of the arrays is shown in Fig.10. In FIG. 10, bits 4518, 4520, and 4522 are selected using filter mask 4514, and the values of each of these bits, 0, 1, and 0, respectively, are selected using filter values 4516. With these filtering criteria, the MPEG 4524 section will be fed to the operational buffers memory 4022 of the receiver / decoder 2020, while the MPEG 4526 section will not be served in the buffers.

 The hardware prefilter 4506 is implemented using a demultiplexer chip without consuming the computing resources of the main processor.

 The microprocessor can use the RAM 4022 of the receiver / decoder 2020, which stores the sections, as a software filter 4526. Using the software filter 4526, you can choose which sections loaded into the buffers of the 4022 RAM volume will be transferred to the application.

 The principles of software filtering are similar to the principles of hardware filtering. Software filter 4526 typically uses 8 consecutive bytes 4528 in the MPEG data of section 4508. As shown in FIG. 11, the position of the first byte 4530 of these eight consecutive bytes is determined by offset 4532 from the first byte 4510 in section 4508.

 If after downloading through a hardware filter the data in the MPEG section does not meet the criteria for software filtering, the buffer in which the MPEG section is stored can be used to load another MPEG section.

To download an MPEG section from an MPEG data stream, an MLOAD device is typically provided with the following information:
PID in the data stream in which this MPEG section should be detected;
an descrambling information array containing a series of ECMs for descrambling the PIDs;
an operator reference that detects a particular ECM that should be used to descramble the given PID;
array of hardware filter values to be applied;
hardware filter mask array to be used;
software filter offset value to be applied;
array of software filter values to be applied;
maximum section size (up to 4096 bytes) and
A timeout function that determines how long the device should wait to load a section, group of sections, or table.

 When it is indicated that the maximum section size is 512 bytes, the section size cannot exceed 512 bytes.

 The section is loaded entirely into the buffer of the 4022 random access memory volume allocated by the device. After the section is loaded and if it meets the criteria for software filtering, the device should free the demultiplexing path and inform the application using an “event” that contains a progress report and the address of the buffer containing the section. After loading, the section is identified by the address of the buffer in which it is stored.

 When a table needs to be loaded, TID 4302 is also transferred to the device. Each section of the table is loaded into the corresponding buffer allocated for it in its entirety. At the same time, tables are not required to be loaded by placing sections continuously and in order. As each section of the table loads, the device can inform the application that this section of the table is loaded. Alternatively, or in addition, the device can inform the application through an event that the entire table has been successfully loaded into allocated buffers.

As shown in FIG. 12, a table is usually loaded as follows (a description of software filtering is omitted solely for reasons of simplicity):
step 1: set the mask array of the hardware filter 4534 and the array of values of the hardware filter 4536;
step 2: load the first section 4538 corresponding to the hardware (and software) filter;
step 3: read the LSN 4540 value of section 4538 to determine the number of sections to be loaded (= LSN + 1), and change the hardware filter mask array 4534 and the array of hardware filter values 4536 in accordance with the LSN 4540 value;
steps 4 to 6: load the remaining sections 4542, 4544 and 4546 in accordance with the TID and LSN values and send the event to the application.

 Table loading is completed only when the event indicating successful loading is entered into the queue of the real-time subsystem 4008. Before this event is placed in the queue of the subsystem, it is possible to successfully interrupt the loading of the table.

 After the table has been loaded, it is identified by the name assigned to it by the application when requesting to load the table.

 Access to information about how the table is stored in the memory of the receiver / decoder 2020 is provided by a call that returns the table descriptor. An example of such a descriptor is shown in FIG. 17. The 4700 descriptor contains a field 4702 containing the total number of sections (LSN + 1) in the table, and a list of 4704 buffers containing sections 4538, 4542, 4544 and 4546 that form the table starting from section 4544 having SN "0", then comes section 4546 with SN "1", etc. to section 4542 having an SN corresponding to an LSN.

 The section group includes all sections that meet the criteria of hardware and software filtering. MPEG sections appear cyclically in the data stream.

 As shown in FIG. 13, the group 4548 is limited to two sections; the first section (SDG) 4550 and the last section (SFG) 4552, each of which meets the relevant filtering criteria, and the remaining sections (SG) 4554 are located between them.

 Loading sections in a group can be done in one of two different loading modes.

 In “follow mode”, a predetermined number of sections 4554 are loaded that immediately follow the SDG 4550. For each type of section (SDG, SG, SFG), the application indicates the TID, hardware filter, software filter and the maximum length of the section.

 As shown in FIG. 14, preferably the device first applies the hardware and software filtering criteria to allow loading and saving of only SDG 4550. This avoids loading the redundant SG 4554 into the volume buffers of the 4022 receiver / decoder 2020 before loading the SDG 4550. After detection, the SDG 4550 is stored in the section memory or buffer 4556. The device then applies the hardware and software filtering criteria to allow the loading of the desired SG and SFG from the group of MPEG data sections.

 In the example of FIG. 14, three SG 4554 from an MPEG section group containing one SDG, seven SG and one SFG must be loaded from the MPEG data stream. After storing the SDG 4550 in buffer 4556, the first SG 4558 from the group of MPEG sections to be transmitted after SDG 4550 is stored in buffer 4560. Similarly, the second SG 4562 from the group of MPEG sections to be transmitted after SDG 4550 is stored in buffer 4564 and the third SG 4566 from the group of MPEG sections to be transmitted after the SDG 4550 is stored in buffer 4568.

 Saving SG continues until either the required number of sections 4554 is saved or the SFG 4552 is loaded. If the SFG 4552 is loaded, it is not stored in the memory.

 As each section of the group is loaded, the device can inform the application through the event that this section of the group is loaded. Alternatively, or in addition, the device may only inform the application of the completion of saving MPEG sections, or of loading SFG 4552 by sending an event to the application.

 In the “precedence mode”, a predetermined number of sections that immediately precede the SFG are stored in the memory sections. For each type of section (SDG, SG, SFG), the application indicates the PID, TID, hardware filter, software filter and the maximum length of the section.

 When loading in this mode, a ring buffer is required to save MPEG sections.

 As shown in FIG. 15, preferably the device first applies the hardware and software filtering criteria to allow loading and saving of only SDG 4570. This avoids loading redundant SG 4554 into the buffers of the 4022 receiver / decoder random access memory volume before loading the SDG 4570. When an SDG 4550 is detected, it is not saved. The device then applies the hardware and software filtering criteria to allow the loading of the desired SG and SFG from the group of MPEG data sections.

 In the example of FIG. 15, three SG 4544 from an MPEG section group containing one SDG, seven SG and one SFG must be loaded from the MPEG data stream. After loading SDG 4570, the first SG 4572 from the group of MPEG sections to be transmitted after SDG 4570 is stored in buffer 4574. Similarly, the second SG 4576 from the group of MPEG sections to be transmitted after SDG 4550 is stored in buffer 4578, and the third SG 4580 of the group of MPEG sections to be transmitted after SDG 4570 is stored in buffer 4582.

 The fourth SG 4584 from the group of MPEG sections to be transmitted after the SDG 4550 is stored in buffer 4574, that is, in the buffer in which the first SG 4572 was stored. Similarly, each of the sequentially transmitted SG 4586, 4588 and 4590 is stored in buffers 4578, 4582 and 4574, respectively.

 Saving SG in such a cyclic manner continues until SFG 4592 is detected by the device. This happens even when the desired number of SGs has not yet been loaded before SFG is detected. Upon detection, SFG 4592 is stored in the buffer and an event is sent to the application indicating that the group was successfully loaded.

 Access to information about how the group is stored in the RAM 4022 of the receiver / decoder 2020 is provided by a special call that returns the group descriptor. An example of such a descriptor is shown in FIG. 16. Descriptor 4600 contains a field 4602 containing the total number of sections in the group, and a list of 4604 buffers containing SDG or SFG (depending on boot mode), and the SG sections that form the group, in boot order.

 After the group has been downloaded, it is identified by the name assigned to it by the application when requesting to download the group.

 It is possible to add a section to a group or delete a section from a group. One section may belong to more than one group.

 When an application requests to add a section to a group, the address of the buffer containing the new section is placed at the end of the 4604 descriptor, and field 4602 is updated. When the application asks for the removal of a section from the group, the address of the buffer containing this section is deleted in the descriptor 4600 and the field 4602 is updated. If this section is not the last section in the group, the descriptor is reorganized to remove empty sections of memory. Thus, after deleting all sections, you can get an "empty group".

 Devices are identified by unique identifiers, for example, "LCARD_ DEVICE_ ID" indicates an LCARD device and "RCARD_DEVICE_ID" indicates an RCARD device.

 When a new 4062 device is created, it can be installed in existing decoders 2020 by downloading the corresponding 4056 "application from the broadcast center. Typically, the maximum number of devices supported by one manager is 256.

 This download is performed in the receiver / decoder 2020 by an application 4056, which checks the software and hardware versions and, if the result is positive, downloads the software module representing the new 4062 device and requests a procedure from the 4058 library to install the code of the new device among other built-in programs (in flash memory). This provides a flexible and safe addition of new functions to the receiver / decoder 2020 without affecting the rest of the software.

 Obviously, the present invention has been described above solely by way of example, and various modifications are possible within the scope of this invention.

 Each feature set forth in the description, as well as (where appropriate) claims and figures, may be provided independently or in an appropriate combination.

 In the aforementioned preferred embodiments, some of the features of the invention are implemented using software. However, an experienced specialist, of course, understands that any of these tools can be implemented in hardware. Further, it is understood that functions performed by hardware, computer software, and the like are performed on or using electrical and similar signals.

 Cross-references are made to our co-pending applications with the same filing date and entitled “Signal Generation and Broadcasting” (Attorney's Case Number PC / ASD / 19707), “Smart Card for Use of Encrypted Broadcast Signal Receiver and Receiver” (number attorney’s files PC / ASD / 19708), “Broadcasting and receiving system and conditional access system for it” (attorney’s case number PC / ASD / 19710), “Downloading a computer file from the transmitter through the receiver / decoder to a computer” (PC attorney’s case number / ASD / 19711), "Broadcasting and receiving television Zion programs and other data "(attorney's case number PC / ASD / 19712)," Data download "(attorney's case number PC / ASD / 19713)," Computer memory organization "(attorney's case number PC / ASD / 19714)," Development television and radio control systems "(attorney's case number PC / ASD / 19715)," Extracting data sections from the broadcast data stream "(attorney's case number PC / ASD / 19716)," Access control system "(attorney's case number PC / ASD / 19717), "Data Processing System" (attorney's case number PC / ASD / 19718), "Broadcasting and receiving system, as well as receiver / decoder and remote Troller for her "(attorney case number PC / ASD / 19720). Disclosure of the contents of these documents is incorporated herein by reference. The list of applications includes the proposed invention.

Claims (18)

 1. A method of extracting from a broadcast data stream and storing a plurality of data sections from a group of such sections having at least one common section attribute, including the following operations: (a) receiving a data stream, (c) filtering one section from said data stream from said groups in accordance with said at least one sign of a section, (c) storing said one section, characterized in that it includes the following operations: (d) repeating operations (c) and (c) to save some predetermined number and sections from the said group, taken after said one section, and in the first mode of operation, a predetermined number of sections following a certain section in the said group is stored, while in the second mode of operation, a predetermined number of sections preceding a certain section in mentioned group.  2. The method of claim 1, wherein said group of sections has a first section and a last section, and in said first mode, operation (d) comprises storing a predetermined number of sections of said group immediately following said first section of this group, whereas in said in the second mode, operation (d) includes storing a predetermined number of sections of said group immediately preceding said last section of this group.  3. The method according to p. 1 or 2, in which each section is stored in the corresponding memory location.  4. The method according to p. 3, in which, after saving, each saved section is identified by the address of the memory in which it is stored. 5. The method according to any one of the preceding paragraphs, in which the aforementioned first section of this group is filtered out of the transmitted data stream
6. The method of claim 5, wherein in said first mode, operation (d) includes sequentially storing sections of a group sequentially received and filtered immediately after said first section, wherein each section is stored in a corresponding memory location until one of the two is performed - the aforementioned predetermined number of sections is stored, and before the aforementioned predetermined number of sections is stored, the last section is stored.  7. The method according to claim 5 or 6, in which, in said second mode, operation (d) includes an operation of sequentially storing sections sequentially received and filtered immediately after said first section, wherein each section is stored in the corresponding memory section until one of the two is not fulfilled - the aforementioned predetermined number of sections is saved, after which the sections already stored in the memory sections are sequentially overwritten by subsequent received and filtered sections until children said last section is stored and before the stored predetermined number of sections, said last section is stored.  8. The method according to any one of the preceding paragraphs, wherein said filtering operation includes the following operations: setting at least one filtering characteristic, each characteristic containing a filtering criterion and a value for this filtering criterion, comparing each section characteristic with a corresponding filtering sign, and filtering said one section from said data stream in the case where each section characteristic corresponds to a corresponding filtering attribute.  9. The method according to any one of the preceding paragraphs, which further includes the following operation: supplying a section identification signal to some application after saving any section from the said group.  10. The method of claim 9, wherein said section identification signal comprises a storage address of said stored section.  11. A device for extracting from a broadcast data stream and storing a plurality of data sections from a group of such sections having at least one common feature of a section, comprising means for receiving a data stream, means for filtering from said data stream one section from said group in accordance with said at least one feature of the section, the storage means of said one section, characterized in that said filtering means and storage means are arranged to store some of a predetermined number of sections from said group, taken after said one section, and in the first mode of operation, a predetermined number of sections following a certain selected section in said group is stored, while in a second mode of operation, a predetermined number of sections preceding some selected section in said group.  12. The device according to claim 11, in which said group of sections has a first section and a last section, and said filtering means and storage means are configured to store in said first mode a predetermined number of sections immediately following said first section of this group, and save in said second mode of a predetermined number of sections immediately preceding said last section of this group.  13. The device according to p. 11 or 12, in which the said means of storage contains many sections of memory for storing the respective sections.  14. The device according to p. 13, comprising means for identifying each stored section using the address of the memory section in which the section is stored. 15. The device according to any one of paragraphs. 11-14, in which the said filtering means is configured to initially filter out from the broadcast data stream the said first section of this group
16. The device according to p. 15, in which in the aforementioned first mode, said filtering means and storage means are configured to store sections of a group sequentially received and filtered immediately after said first section, with each section being stored in the corresponding memory section until one of the two is performed - the aforementioned predetermined number of sections is stored, and before the aforementioned predetermined number of sections is stored, the last section is stored.  17. The device according to p. 15 or 16, wherein in said second mode, said filtering means and storage means are configured to store sections sequentially received and filtered immediately after said first section, with each section being stored in the corresponding memory section until until one of the two is fulfilled, the aforementioned predetermined number of sections is saved, after which the sections already stored in the memory sections are sequentially overwritten by the subsequent received and unchanged by leaking sections until said last section is saved and before the predetermined number of sections is stored, said last section is saved.  18. The device according to any one of paragraphs. 11-17, wherein said filtering means comprises: means for defining at least one filtering characteristic, each characteristic comprising a filtering criterion and a value for this filtering criterion, means for comparing each section characteristic with a corresponding filtering attribute, and means for filtering said one section from said data flow in the case when each feature of the section corresponds to the corresponding filter feature.  19. The device according to any one of paragraphs. 11-18, which further comprises means for supplying the section identification signal to some application after storing any section from the said group.  20. The apparatus of claim 19, wherein said section identification signal comprises a storage address of said one section.

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