EP1568225A1

EP1568225A1 - Module, system and method for processing digital signals

Info

Publication number: EP1568225A1
Application number: EP03786054A
Authority: EP
Inventors: Philippe Guenebaud
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-12-03
Filing date: 2003-11-13
Publication date: 2005-08-31
Also published as: WO2004054258A1; AU2003295058A1; FR2848043B1; US20060053457A1; FR2848043A1

Abstract

The invention relates to a digital signal-processing module (2) which can be connected to a host (1) for receiving at least one input transport stream of encoded digital data in a pre-determined compression format. The inventive module comprises means of decoding the digital signals contained in the input transport stream. The invention also relates to a system comprising the aforementioned module (2) and to a method of receiving and processing digital signals. The invention is particularly suitable for use in the field involving the reception and decoding of digital transport streams for the broadcasting of audio-visual programmes.

Description

"Module, system and method for processing digital signals"

The present invention relates to a digital signal processing module and a system and method for receiving and processing digital signals.

The invention will particularly find its application in the field of digital television, in particular for the reception and processing of digital data transport streams supporting digital signals for broadcasting audiovisual programs, generally comprising an audio part and a video part.

Digital television has experienced a great boom in recent years, both by satellite broadcasting and by terrestrial network and in particular by cable. Television programs are routed to the viewer via digital transport streams, generally consisting of multiplex streams integrating a plurality of programs.

In addition, the data contained in digital transport flows is generally scrambled to avoid piracy in the case of pay television.

In addition to the scrambling processing, the data also undergoes - usually encoding in a predetermined compression format such as MPEG2 (Moving Picture Experts Group) or MPEG 4 and MP3 format (in the audio field).

Compression of data in such formats is generally required by a desire to reduce costs (by limiting bandwidth in transmission operations) or by limiting storage capacities.

The digital data transport streams are received by the user by means of a device generally called a decoder or set top box ensuring reception, possible descrambling, audio and video decoding and adaptation of the signals in order to their exploitation (in particular adaptation to PAL / SECAM format and analog to digital conversion for display on television).

Generally, the descrambling operation is carried out by means of authorization conferred on the user for a fee. These authorization means are for example supported by means of a smart card capable of cooperating with a smart card interface integrated in the set top box so as to issue authorization keys capable of being implemented by the descrambling algorithm implemented in the set top box.

According to the most common case currently, the set top box includes common descrambling means for different types of television operators.

This system, commonly called DVB descrambler, allows operators to offer their services via decoders or set top boxes standardized a security term. This technology is particularly implemented within the framework of the DVB (Digital Video Broadcasting) standard.

A disadvantage of this common descrambler technology is that the authorization means contained on the chip card, which are less resistant, then represent an easy attack for potential hackers. If the attack on the authorization means is successful by the hackers, it turns out to be necessary to replace the smart cards in large numbers, without any assurance that the newly obtained security will last a long time.

We currently note that the replacement of smart cards only resists a new hacking for a few months. It is also not It is possible to change the set top boxes in the event of piracy, as this represents an extremely costly logistical operation and which should be generalized to all set top boxes, taking into account the principle of the common interface used.

In addition, the compression technology used for digital transmission (MPEG2), common to all reception decoders is made of hard (hardware components) and an evolution towards new, more efficient decompression technologies (MPEG4, H264, etc.). .) is impossible, except by changing the decoders.

Other types of set top box are also known which can be used for the DVB-CI standard (for common interface) and which use a conditional access module. In this context, document WO-A-0174075 presents a system comprising a portable conditional access block of the removable smart card interface type. This conditional access block can cooperate with an intelligent receiver of the set top box type. The intelligent receiver is adapted to receive different types of separate removable smart card interfaces depending on the content operators (such as operators of digital broadcasting systems). A smart card is provided by each operator and can be inserted by the user in the corresponding removable smart card interface. A scrambling key provided by the operator of the digital broadcast system is used in the smart card to execute a descrambling algorithm for scrambled audio and video data received by the smart receiver. The removable smart card interface allows the interchangeability of conditional access blocks according to the descrambling algorithm specific to the operator of the digital broadcasting system. As a result, the same smart receiver can be used by different digital broadcast operators using different encryption keys and separate encryption algorithms.

A drawback of these devices is that a clear stream compressed in a compression format (for example MPEG2) is accessible at the connection terminals of the smart card interface. It is generally a PCMCIA type interface with widely used connectors. At this connection, the speed of which is very low (a few Mbit s), it appears possible to hack and record the compressed descrambled stream coming from the connector. Another drawback of these systems is that they do not allow the implementation of interactive services, that is to say allowing the feedback of information from the user's device to the server of the broadcasting operator. digital. Indeed, conditional access modules or conditional access blocks are not capable of receiving a complete interactivity engine. They do not have enough power and memory for this purpose, and especially the communication interface ("Command Interface") does not allow a speed compatible with a real interactive service. The DVB-CI standard did not provide for this functionality. The techniques known up to now therefore have numerous drawbacks linked to their intrinsic weaknesses with regard to piracy and also to the lack of flexibility in their use. There is therefore a need relating to a system providing a solution to these various drawbacks.

To this end, the present invention presents a system which has the advantage of removably and removably deporting the majority or all of the essential functions of the reception and processing system.

In particular, decoding from a predetermined compression format is carried out within the external module so as to transfer intelligence from the system to the module rather than preserving it in the set top box.

An advantage of the invention is that the module is replaceable and customizable by the operator. Its resistance to piracy is therefore much higher. It also provides greater flexibility for operators broadcasting television programs because it can be modified or replaced in the event of piracy.

The set top box used according to the present invention has the advantage of becoming truly universal regardless of the descrambling or scrambling mode carried out and the type of compression format to be coded and decoded.

This universality is however carried out without penalizing the security of the whole system, on the contrary.

Others and aims and advantages will appear during the following description of a preferred embodiment of the invention. The present invention relates to a digital signal processing module capable of being connected to a host for receiving at least one incoming transport stream of digital data encoded in a predetermined compression format. It includes means for decoding digital signals contained in the incoming transport stream.

This module can be presented according to the variants set out below:

- It includes means for descrambling scrambled digital signals contained in the incoming transport stream, - It includes means for decryption authorization,

- It includes means for demultiplexing and prior filtering of the incoming transport flow,

- It includes means for encoding digital signals in at least one other compression format, for transcoding, - It includes means for temporary or permanent storage of digital signals,

- It includes means for controlling its interface with the host,

- The incoming transport stream is a digital data transport stream of audiovisual programs. The invention also relates to a system for receiving and processing digital signals comprising a host for receiving at least one transport stream of digital data encoded in a predetermined compression format and a processing module capable of being connected to the host. This system will be, in preferred embodiments such as: - The host comprises a connection interface with the processing module, said interface comprising a signal input from a reception part of the host and an output from signal to a signal adaptation part for displaying the host,

- The interface is controlled by the processing module, - It comprises at least one additional processing module able to be connected to the host by the interface,

- It includes a digital data storage unit, - The storage unit is able to be connected to the host by the link interface,

- The processing module comprises means for local encryption of data with a view to their storage on the storage unit, - It comprises an analog-to-digital converter connected as an input to the processing module for additional processing of analog signals,

The invention also relates to a method for receiving and processing digital signals, comprising a step of reception by a host of at least one incoming transport stream of digital data encoded in a predetermined compression format.

The incoming transport stream is transmitted from the host to a processing module; in the processing module, digital signals contained in the incoming transport stream are decoded; the processed signals are returned to the host. Advantageously, the following additional process steps are carried out:

- in the processing module, demultiplexing and filtering of the incoming transport stream is carried out before decoding,

- we receive scrambled digital signals contained in the incoming transport stream,

- descrambling of the scrambled digital signals in the processing module is carried out,

- we use a storage unit for the storage of digital data from the incoming transport flow. - the digital data from the incoming transport flow is stored on the storage unit,

- the digital data is transmitted, offline, to the processing module for processing,

- the digital module is decoded in the processing module and then encoded in another data compression format, - the digital data thus transcoded is stored in the storage unit, - the digital data of the processed signals is encrypted in the processing module,

the encrypted processed signals are stored on the storage unit,

- several incoming transport flows are received, - the incoming transport flows are transmitted to the processing module for processing,

- the processed signals are returned to the host for storage and / or display,

- at least one additional processing module is used,

- Decoding is carried out from different compression formats in the different processing modules.

The attached drawings are given by way of examples and are not limitative of the invention. They represent only one embodiment of the invention and will make it easy to understand it.

Figure 1 shows schematically the current mode of reception and processing of transport streams of digital data from satellite reception.

FIG. 2 also illustrates the current state of the art and various components of the set top boxes used.

FIG. 3 shows different components of the system according to the invention in a preferred embodiment. Figure 4 shows an example of routing and processing of digital signal transport flows.

FIG. 5 shows an example of components of the module of the invention.

FIG. 6 shows more precisely a possible hardware implementation of the module of the invention.

FIG. 7 illustrates an additional possibility of the invention for a local backup copy of encrypted data.

Figure 8 shows a variant of the invention with an additional storage unit. Figure 9 and Figure 10 show different cases of operation of the system of the invention according to this variant.

FIG. 1 illustrates a case of operation of the invention according to a variant implementing two modules and a data storage unit. As a preliminary, it is indicated that the present description is given without limitation in the context of an application to digital television. The processed data streams generally include an audio part and a video part in this context. However, this example is not limitative of the invention.

According to the current state of the art represented in FIG. 1, a telecommunication network 4 ensures the transmission from the server of the digital broadcasting operator of a digital stream 5 supporting one or more digital television programs. Generally, the incoming digital stream 5 is a scrambled multiplex stream to avoid piracy and encoded in a predetermined compression format. The reference 8 in FIG. 1 shows an example of an encrypted coded signal entering and supported in the incoming digital stream 5. At this stage, the signal 8 cannot be used directly by the user. The incoming digital transport stream 5 is received according to the state of the art in a decoder 50 commonly called set top box. The decoder 50 cooperates with a support of authorization means delivered by the operator to the user and for example constituted by a smart card 51.

After delivery of the authorization means contained on the smart card 51 to the decoder 50, the latter performs a processing of the incoming digital stream 5 so as to obtain signals which can be used by the user and intended in particular for viewing on a television set 3 .

FIG. 2 more particularly illustrates an example of different components present in a decoder 50 according to the state of the art. In this context, the decoder 50 first comprises a reception part comprising a tuner 6a whose input is connected to an antenna or to any cable. This tuner 6a is connected to a demodulator 6b so that the demodulated signals are then transmitted to a descrambling system 55 also able to operate a demultiplexing of the stream. The demultiplexer generally includes a certain number of filters programmed by a microprocessor according to the various applications supported by the decoder. At the descrambler 55, encryption keys are used by the descrambling algorithm and depend on the authorization means contained in the user's smart card 51. Via a smart card interface 52, the user inserts the smart card 51, which allows the decoder 50 to access the authorization means that can be used by the descrambler 55. At the output of the descrambler 55, the data are organized by package and are descrambled.

Their decoding is then carried out, consisting in passing from a predetermined compression format to a decompressed format. This decoding is carried out at decoders generally comprising an audio decoder 53 and a video decoder 54.

At this stage, the digital processing is finalized and the signals are transmitted to an adaptation part for display. The adaptation operations essentially consist of an adaptation of PAL or SECAM format as well as a digital analog conversion at the block level respectively

7a, 7b, 7c.

At the output of blocks 7b and 7c, an analog signal usable by the television set 3 is obtained.

As explained above, it can be seen that the set top box currently used performs the essential steps of digital processing. This treatment concerns in particular the following stages:

- descrambling (consisting in obtaining a decrypted flow by means of the authorization means delivered to the user by an operator).

- Decoding consisting in passing from a predetermined compression format such as MPEG2, MPEG4, or MP3 to a decompressed format.

- The preliminary digital processing phases including demultiplexing of the digital transport stream and data filtering.

The module and the system of the present invention make it possible to deport all or part of these essential steps of digital processing. In this context, the system of the invention comprises a host 1 which can present itself externally in a manner similar to the set top boxes or decoders 50 currently used and which conventionally have a receiving part 6 comprising a tuner 6a and a demodulator 6b as well 'a part adaptation adapter for the display 7 conventionally comprising a format adapter 7a (for example PAL / SECAM) and analog digital converters 7b, 7c of the video and audio signals. The host 1 also comprises various connection elements allowing the connection of the tuner 6a for example to an antenna or terrestrial reception means, as well as the output connection to a television set 3. The host 1 can also be controlled by a remote control 9.

Typically, the host 1 of the invention cooperates with a processing module 2 also shown diagrammatically in FIG. 3. The connection between the processing module 2 and the host 1 can be carried out in different ways and for example by through a serial link of USB type (Universal Serial Bus). To manage communications between host 1 and the processing module

2, an interface is present in the host 1 and is advantageously controlled by the processing module 2. It is therefore entirely slave. Figure 3 illustrates the flow of data within the system of the invention. In particular, it has been presented that the data coming from the tuner 6a and from the demodulator 6b reach the interface 12 for transmission to the processing module 2.

Then, the processed data is returned by the processing module 2 to the host 1 still via the interface 12 for transmission to the adaptation part for the display 7 and finally operation by the television set 3.

FIG. 4 shows more precisely the processing of the digital signals operated within the processing module 2. This processing consists firstly of decoding the digital signals contained in the incoming transport stream 5 (originating from the operator's broadcasting system) ) to convert data from a predetermined compression format (usually MPEG2) to a decompressed format. The processing module 2 therefore includes decoding means

15, 16 allowing a clear flow 31 to be returned to host 1. After returning to the host 1, a clear video signal 36 and a clear audio signal 37 can be supplied to the adaptation part 7 for display and sound. Advantageously and in the case where the system of the invention is used for access to pay television programs, the processing module 2 also comprises descrambling means 13 able to cooperate with decryption authorization means 14 specific to the user and the operator so as to descramble the flow delivered by the operator.

The block 13 also advantageously comprises conventional preprocessing means consisting of demultiplexing and prior filtering of the incoming transport stream 5. Once the preprocessing and descrambling have been carried out at block 13, the data is transmitted to the decoding means. (audio decoder 16 and video decoder 15) also contained in the processing module 2. This configuration is illustrated in FIG. 5.

As an indication, an embodiment of the processing module 2 is shown in FIG. 6. In this context, the module 2 comprises the following elements: a controller 17, an authorization storage area 18 (making it possible to contain the means decryption authorization), a data storage area 19 (consisting of a dynamic memory of the DRAM type), a program storage area 20, a descrambling accelerator 21 for filtering 22 for decryption 23, for audio decoding 24 and video 25. The processing module 2 finally comprises a master interface 35 for communication with the host 1.

According to a preferred embodiment, the processing module also comprises means for encoding 26, 27 of digital signals making it possible, after the decoding operation, to encode the digital signals in another compression format. This allows transcoding, for example from MPEG2 format to MPEG4 format, or from MPEG2 format to MP3 format for audio signals, in order to significantly reduce their size.

This transcoding operation makes it possible in particular to allocate the data for storage at the level of a storage unit 10. According to the example of FIG. 8, the storage unit 10 is offset relative to the processing module 2 and to the host 1. However, this solution is not limiting and the integrated storage unit 10 could be used either in host 1 or in processing modules 2. In addition, the storage unit 10 is advantageously also controlled by means for controlling the module 2.

In the example of FIG. 8, the transport stream 5 received by the host 1 (step A) is transmitted by the interface 12 to the processing module 2 (step B) 5 in order to carry out a decoding operation there then d encoding for storage in the storage unit 10 in a desired compression format (steps C and D). These phases of data transmission between the various constituent elements of the system are particularly marked from A to D in FIG. 9.

When the user wishes to view the data stored in

10 the storage unit 10, the diagram shown in FIG. 10 operates. In this context, the stored data is retransmitted from the storage unit 10 to the interface 12 (step A) for transmission to the processing module 2 (step

B). At this level, the data is decoded for exploitation by the host 1

(step C). In phase D, the signals are transmitted to the television for the

15 viewing. In addition to the encoding and decoding operations carried out by the processing module in this context of cooperation with the storage unit

10, the scrambling and descrambling operations can be used, in particular for storing scrambled data on the storage unit in order to avoid piracy.

FIG. 7 shows more precisely means that can be used to perform local backup of the data on the storage unit 10.

The assembly thus formed allows the generation of signals in the desired format. In order to ensure data security, a key generator 30 is also present for transmitting local copy keys to local encryption means 28 and local decryption means 29.

Thus, when the user wishes to make a local copy, the clear video and audio signals 32, 33 are received at the video and audio encoders 26 and 27 for encoding in the desired format (for example MPEG4 and MP3). The signals thus compressed are received by the local encryption means 28 where they are scrambled by means of the local encryption keys generated by the generator 30. At the output, encrypted signals are obtained - - and encoded 38. When the user wishes to replay the data thus stored, the encrypted encrypted signals 34 are received as input by local decryption means 29 capable of descrambling them by means of keys, then transmitting the descrambled signals to the decoder 15, 16 for generation of clear and decompressed video and audio signals 36, 37 at output.

A processing module 2 can integrate one or more types of decoding and encoding means according to the compression format which one wishes to achieve or from which one wishes to decode.

According to a variant of the invention, the system comprises at least one additional processing module 11 also able to be connected to host 1 by the interface 12. This configuration makes it possible in particular with a single host 1 to have different modules for processing 2 corresponding to different digital broadcasting operators.

By means of the invention, it is possible to carry out simultaneous processing of two (or more) streams of digital data. This functionality will find its application for example to the realization of Picture i n Picture functions (consisting in superimposing an image in another) or also to operate a storage of data corresponding to a program while viewing the data of another program. In this context, FIG. 11 shows an example of simultaneous work on a plurality of flows in the case of the variant implementing two processing modules of 11.

In this application, it is possible for example to use the first processing module 2 for decoding and encoding digital data to or from the MPEG2 format. The additional processing module 11 is intended for encoding and decoding digital data in MPEG4 and MP3 format.

In the context of the example in FIG. 11, a digital data stream 1 is received at the reception part 6 of the host 1 (step A). In addition, the storage unit 10 transmits another stream corresponding to data stored at the interface 12 of the host 1 (step B). The incoming transport flow is transmitted by the interface 12 to the processing module 2 as shown in the arrow marked C. In parallel, the data from the storage unit is transmitted by the interface 12 to the additional processing module 11 as shown by arrow D. In the additional processing module 11, the data is decoded to be returned as shown in FIG. arrow marked E at the interface 12 for transmission to the processing module 2 as shown by the arrow marked F. The data originating from the flow of the arrow marked C are processed in the processing module 2 so as to be in particular demultiplexed, filtered, descrambled (if applicable) and decoded from their original compression format. At this stage, the processing module 2 includes the data in clear from the incoming transport flows identified by the arrow A and from the storage unit 10. All of these digital signals in clear can then be returned to the interface 12 for operation by host 1 as shown by the arrow marked G. This operation may for example consist of an overlay of the Picture in Picture type on the screen, but this example is not limiting.

According to one possibility of the reception and processing method of the invention, the digital data from an incoming transport stream 5 is stored on the storage unit 10 in order to retransmit it to the processing module 2 for processing the data. This allows for example to store a stream received live on the storage unit and to perform processing at the module level only later (for example taking into account the processing time required for re-encoding, for work during a low period of use, for example at night). Thus, the stream received directly is stored in the storage unit 10 then is returned to the processing module 2 for a compression job and is finally returned compressed in the desired format on the storage unit. It can be seen that, in this example, the required power of the module is less, which makes it possible to reduce the silicon surface, the power to be dissipated and the cost of the module.

According to another variant of the invention, the system comprises a

- analog to digital converter connected at the input to the processing module 2, so as to allow additional processing of analog signals. Through example, this configuration makes it possible to connect the processing module 2 to a terrestrial television source in analog format or else to an analog data storage unit such as a video recorder.

This configuration also makes it possible to receive audio data originating from analog reception means, for example via a hi-fi system. The analog signals thus received as input by the processing module 2 are digitalized by the analog to digital converter and can be used in addition to the digital data described above in the context of the invention. In particular, the processing module 2 can process the data coming from the analog signals so as to encode them for storage on the storage unit 10.

REFERENCES

1. host

2. processing module 3. television

4. telecommunications network

5. incoming digital stream

6. reception part 6a. tuner 6b. demodulator

7. display adaptation part 7a. format adapter

7b. video D / A converter

7c. audio D / A converter 8. incoming encrypted coded signal

9. remote control

10. digital data storage unit

11. additional processing module

12. interface 13. descrambling means

14. means of authorization for decryption

15. video decoder

16. video decoder

17. controller 18. authorization storage area

19. data storage area

20. program storage area

21. descrambling accelerator

22. filter accelerator 23. decryption accelerator

24. audio decoding accelerator - 25. - video decoding accelerator

26. video encoder 27. audio encoder

28. local encryption means

29. means of local decryption

30. key generator 31. clear and unzipped flow

32. clear video signal at input

33. clear audio signal at input

34. incoming encrypted signals

35. master interface 36. clear video signal output

37. clear audio signal output

38. outgoing encrypted signals 50. decoder 51. Smart card 52. Smart card interface

53. audio decoder

54. video decoder

55. descrambler

Claims

1. digital signal processing module (2) able to be connected to a host (1) for receiving at least one incoming transport stream (5) of digital data encoded in a predetermined compression format, characterized by the fact than,

It comprises means for decoding (15, 16) of digital signals contained in the incoming transport stream (5).

2. Module according to claim 1, characterized in that,

It includes descrambling means (13) of scrambled digital signals contained in the incoming transport stream (5).

3. Module according to claim 2, characterized in that, II comprises means for decryption authorization.

4. Module according to any one of claims 1 to 3, characterized in that,

It includes means for demultiplexing and prior filtering of the incoming transport flow (5).

5. Module according to any one of claims 1 to 4,

Characterized by the fact that,

It comprises means for encoding (26, 27) of digital signals in at least one other compression format, to perform transcoding.

6. Module according to any one of claims 1 to 5, characterized in that,

It includes means for temporary or permanent storage of digital signals.

7. Module according to any one of claims 1 to 6, characterized in that, II comprises means for controlling its interface (12) with the host

1). -

8. Module according to any one of claims 1 to 7,

Characterized by the fact that, The incoming transport stream is a digital data transport stream of audiovisual programs.

9. Digital signal reception and processing system comprising a host (1) for receiving at least one transport stream (5) of digital data encoded in a predetermined compression format and a processing module (2) capable of be connected to the host (1),

Characterized by the fact that,

It comprises a processing module (2) according to any one of claims 1 to 8.

10. System according to claim 9,

Characterized by the fact that,

The host has an interface (12) for connection to the processing module (2), said interface (12) comprising a signal input from a reception part (6) of the host (1) and an output signal to a signal adaptation part for the display (7) of the host (1).

11. System according to claim 10, characterized in that,

The interface (12) is controlled by the processing module (2).

12. System according to any one of claims 9 to 11, characterized in that,

It comprises at least one additional processing module (11) able to be connected to the host (1) by the interface (12).

13. System according to any one of claims 9 to 12, characterized in that, II comprises a storage unit (10) of digital data.

14. System according to claim 13 in combination with any one of claims 10, 11, or 12,

Characterized by the fact that,

The storage unit (10) is capable of being connected to the host (1) by the link interface (12).

15. System according to claim 13 or 14, - - - -Characterized in that, - The processing module (2) comprises means for local encryption of data with a view to their storage on the storage unit (10).

16. System according to any one of claims 9 to 15, characterized in that,

5 It comprises an analog-to-digital converter connected at the input to the processing module (2) for additional processing of analog signals.

17. A method of receiving and processing digital signals, comprising a step of reception by a host (1) of at least one incoming transport stream (5) of digital data encoded in a format of

10 predetermined compression,

Characterized by the fact that,

- the incoming transport stream (5) is transmitted from the host (1) to a processing module (2);

- in the processing module (2), digital signals are decoded contained in the incoming transport stream (5);

- the processed signals are sent back to the host (1).

18. Method according to claim 17, characterized in that,

In the processing module (2), demultiplexing and 0 filtering of the incoming transport stream (5) are carried out before decoding.

19. Method according to claim 17 or 18, characterized in that,

- one receives scrambled digital signals contained in the incoming transport stream (5); 5 - descrambling of the scrambled digital signals is carried out in the processing module (2).

20. Method according to any one of claims 17 to 19, characterized in that,

A storage unit (10) is used for storing the digital data 0 coming from the incoming transport stream (5).

21. The method according to claim 20, ^"" characterized in that, - the digital data from the incoming transport stream (5) is stored on the storage unit (10);

- the digital data is transmitted, deferred, to the processing module (2) for processing.

22. Method according to claim 20 or 21,

Characterized by the fact that,

- In the processing module (2), digital data is decoded and then encoded in another data compression format - the digital data thus transcoded is stored in the storage unit (10).

23. Method according to any one of claims 20 to 22, characterized in that,

- The digital data of the processed signals is encrypted in the processing module (2);

- The encrypted processed signals are stored on the storage unit (10).

24. Method according to any one of claims 17 to 23 characterized in that, - we receive several incoming transport flows (5);

- the incoming transport flows (5) are transmitted to the processing module (2) for processing;

- the processed signals are returned to the host (1) for storage and / or display.

25. Method according to any one of claims 17 to 24,

Characterized by the fact that,

- at least one additional processing module (11) is used

- decoding is carried out from different compression formats in the different processing modules (2, 11). 1/11

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