Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/45—Management operations performed by the client for facilitating the reception of or the interaction with the content or administrating data related to the end-user or to the client device itself, e.g. learning user preferences for recommending movies, resolving scheduling conflicts
  • H04N21/454—Content or additional data filtering, e.g. blocking advertisements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
  • H04N21/234—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
  • H04N21/2347—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving video stream encryption
  • H04N21/23476—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving video stream encryption by partially encrypting, e.g. encrypting the ending portion of a movie
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
  • H04N21/44—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs
  • H04N21/4405—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs involving video stream decryption
  • H04N21/44055—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs involving video stream decryption by partially decrypting, e.g. decrypting a video stream that has been partially encrypted
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/45—Management operations performed by the client for facilitating the reception of or the interaction with the content or administrating data related to the end-user or to the client device itself, e.g. learning user preferences for recommending movies, resolving scheduling conflicts
  • H04N21/4508—Management of client data or end-user data
  • H04N21/4532—Management of client data or end-user data involving end-user characteristics, e.g. viewer profile, preferences
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
  • H04N21/83—Generation or processing of protective or descriptive data associated with content; Content structuring
  • H04N21/835—Generation of protective data, e.g. certificates
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
  • H04N7/16—Analogue secrecy systems; Analogue subscription systems
  • H04N7/162—Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing
  • H04N7/163—Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing by receiver means only

Definitions

• the present invention relates to the field of processing digital audiovisual streams.
• the present invention relates more particularly to a device capable of securely transmitting a set of films of high visual quality to a viewing screen such as a television screen and / or to be recorded on the hard disk or on any other medium.
• recording of a box connecting the remote transmission network to the display screen such as a television screen, a projector or a personal computer monitor, while preserving the audiovisual quality but avoiding any fraudulent use such as the possibility of make pirated copies of films or audiovisual programs recorded on the hard disk or any other recording medium of the set-top box.
• the invention relates to a client-server system and the synchronization mechanism between the server which provides the secure digital stream enabling the audiovisual content to be viewed and the client which reads and displays the digital audiovisual stream.
• This analysis of the flow mainly consists in marking the TS packets containing essential information for a correct decoding of the video, in the MPEG sense, so that in a second encryption phase, only the useful data of the marked TS packets are encrypted.
• essential information is not available for unauthorized decoding, and the stream cannot therefore be displayed, while keeping a reasonable calculation time for the encryption.
• this solution does not solve the security problem because the protection of the video stream is based on an encryption system based on digital keys, but for which the video stream transmitted to a receiving device contains, in an encrypted form, all the information initially present in the original video stream.
• the video stream received by the client equipment already contains all the information initially present in the unencrypted video stream, even if it is stored in a form which does not allow its immediate use.
• a malicious user while being disconnected from the network, can process the encrypted video stream so as to put it back in a form usable by a conventional video decoder and can thus bypass the protection system.
• the present invention relates to the general principle of a method for securing an audiovisual stream.
• the objective is to authorize video-on-demand and pay-per-view services across all broadcast networks and local recording in the memory of the user's digital set-top box, as well as live or online viewing. deferred, television channels.
• the solution is to permanently store outside of the user's home, in fact in the broadcasting and transmission network, part of the audiovisual program recorded by the user or broadcast live, this part being essential. to view said audiovisual program on a television screen or monitor type, but being of a very low volume compared to the total volume of the program digital audiovisual recorded at the user's home or received in real time. The missing part will be transmitted in real time via the broadcasting network (transmission) when the said audiovisual program is viewed.
• modified main stream Most of the audiovisual stream, called “modified main stream” will therefore be transmitted via a conventional broadcasting network, while the missing portion called “additional information" will be sent on demand via a narrowband telecommunications network like conventional telephone networks. or cellular networks of the GSM, GPRS or UMTS type or using a small part of a DSL or BLR type network, or even using a subset of the shared bandwidth on a cable network.
• the audiovisual stream is reconstructed on the recipient equipment (decoder) by a synthesis module from the modified main stream and additional information.
• decoder recipient equipment
• synthesis module from the modified main stream and additional information.
• the integration of its protection systems into channel decoders poses certain problems linked to the architecture of these decoders and the way they treat the data.
• the majority of chain decoders use an intermediate format called PES (“Packetized Elementary Stream”), for processing and viewing data.
• PES Packetized Elementary Stream
• the present invention provides a protection system, comprising an analysis and scrambling module based on the PES format and respectively an analysis and descrambling module, and which is therefore easily integrated into existing digital audiovisual stream decoders .
• the present invention relates to a method for the secure distribution of original digital audiovisual streams consisting of audio, video or other data components, characterized in that said original stream is a stream packaged in logical entities, called packets , manipulable and modular in size, each packet comprising a header containing information on said packet and a payload comprising part of the data of the stream, and in that one proceeds, before the transmission to the client equipment, analysis of said packaged stream to generate a main stream conforming to the packaged format of the original stream, modified in that all or part of said packets constituting it have been replaced by packets of the same structure, but the content of which has been modified, and additional information of any format, able to allow the reconstruction of said original flow, then to trans separately putting said modified main stream and said additional information thus generated from the server to the recipient equipment.
• packets logical entities
• each packet comprising a header containing information on said packet and a payload comprising part of the data of the stream
• the method according to the invention has the following specific characteristics: • the substituted packets contain information relating to one or more audio or video streams included in the packaged stream
• each package incorporates all or part of one (or more) access unit (s)
• the complementary information contains the substituted packets coming from the original nominal flow • the complementary information contains the packets representing said access units
• the additional information also includes synchronization data containing time references and metadata associated with the modified or substituted packets
• the additional information also includes instructions describing actions to be performed on the packets following the processed packet
• the invention also relates to equipment for manufacturing an audiovisual stream comprising at least one multimedia server containing the original audiovisual sequences and a device for analyzing the audiovisual stream originating from said server to generate said modified main stream and said additional information.
• the equipment further comprises a standard packaged stream player, at least one recording interface (hard disk) intended to store the content of said modified main stream, at least one decoder element processing the packaged format. and at least one display and hearing interface, characterized in that it includes a means for recomposing the original stream from said modified main stream and from said additional information.
• the invention also relates to a system for the transmission of an audiovisual stream comprising equipment for producing an audiovisual stream and at least one piece of equipment for operating an audiovisual stream and at least one communication network between the equipment for production and operating equipment (s).
• a packetized elementary stream is an infinite series of digitally coded images (frames, planes), which can be of intra type (reference image I), predicted (P images) or bidirectional (images B), as described for example in MPEG formats.
• a packaged elementary audio stream is a series of audio frames or blocks. These coded video or audio frames are of different sizes and constitute what are called Access Units.
• an elementary stream ES (“Elementary Stream”) undergoes an intermediate packaging step, which allows to cut it into useful and easily manipulated packages called PES packages.
• the resulting flow is called Packaged Elementary Flow (PES).
• a PES packet of a packaged elementary stream is a logical structure made up of a header and a payload.
• the payload simply represents the data taken directly from the access units of the elementary stream to be packaged.
• the start of the payload does not have to coincide with the start of an access unit, therefore an access unit can appear anywhere in the PES packet and it is even possible that several units are contained in a single package.
• the header of a PES packet can be of variable length, and mainly includes a packet start prefix, which as the name suggests, allows you to synchronize with the start of a PES packet. This prefix is followed by a stream identifier, which makes it possible to distinguish, in the same program, packets belonging to different elementary streams.
• the header can also contain time stamps, which are of two types.
• the presentation time stamp PTS (Presentation Time Stamp) which specifies the time at which an access unit must be displayed and the decoding time stamp DTS ("Decoding Time Stamp”) which, in turn, specifies the time at which an access unit must be moved from the storage buffer to the decoder to be processed.
• PTS Presentation Time Stamp
• DTS Decoding Time Stamp
• the size of a PES packet can be of variable size and this characteristic gives the flow great flexibility because the length of the PES packets can be shaped according to the intended application.
• the analysis and scrambling system proposed by the present invention is based on the substitution and modification of PES packets. Indeed, as each PES packet contains part of an access unit or several access units, it is easy to remove a certain number of essential packets from the original flow and to replace them with replacement packets which serve as decoys.
• the replacement packages have a format identical to the substituted packages. Before proceeding with the substitution of the packages, they are identified in a unique way, which allows their easy reconstitution.
• each PES packet to be substituted is identified in a unique way by a pair composed of a stream identifier and either the presentation timestamp (PTS) in the case where the access unit included in said PES packet is type I or P, or the decoding time stamp (DTS) in the case where the access unit included in said PES packet is type B.
• PTS presentation timestamp
• DTS decoding time stamp
• the scrambling system receives as input an elementary stream (ES) or a transport stream (TS), transforms it into PES format and after analysis of the content of the PES packets, produces two different streams, a modified main stream which contains the original stream in which a certain number of PES packets have been replaced by “decoy” packets, and additional information which contains the packets with the original values and optionally, the information necessary for the location of these packets in the PES stream and / or instructions for performing changes in the packages that follow the modified package.
• the packets to be replaced are carefully chosen to guarantee a reasonable flow of additional information. Also, for example, a compromise is made between the degree of visual scrambling, and the volume or bit rate of the additional information output from the analysis and scrambling module.
• the original flow is reconstituted in the decoder unit of the recipient equipment in which the analysis / descrambling module is integrated, which according to the modified main flow and the additional information sent in real time reconstitutes a flow strictly identical to the flow original PES.
• the process is lossless.
• the invention will be better understood on reading an exemplary embodiment concerning a stream in MPEG-2 format.
• the invention highlights the integration of a descrambling module into a market decoder (Satellite or Terrestrial).
• This analysis / descrambling system is the counterpart of the analysis and scrambling system detailed above, since it performs the reverse operation of the latter. It shows to what extent the choice of the packaged elementary flow is suitable for processing in hardware platforms.
• the element (1) is the video stream to be scrambled
• the module (2) is the analysis and scrambling module which receives an audio-visual stream in MPEG format as input. 2 TS or MPEG-2 ES, transforms said input stream into an MPEG-2 stream in PES format and generates two parts at its output different: the modified main stream, reconverted into TS format (31) after the substitution of certain PES packets, and additional information (51) of any format.
• the modified main stream (31) is stored in the buffer (3) of the server (4), then is sent in real time to the user via a high speed network (7) which can be for example of ADSL, cable or satellite.
• the additional information (51) is stored in the buffer (5), then is sent to the destination equipment (20) via a low speed transmission means.
• the networks (6) and (7) can be merged into a single network, for example the complementary information (51) is also sent via a broadband network (7).
• the element (20) represents a decoder box for a satellite channel for example.
• the main stream modified (31) in MPEG-2 TS format arrives directly at the input interface (17) and passes via the bus (11) to the demultiplexer (12).
• the demultiplexer (12) generates a packaged elementary stream (PES) and sends it back to the data bus (11) to be processed and / or stored.
• the main stream modified at the input of the demultiplexer (12) comes from the hard disk (13) of the decoder unit.
• the modified main stream (31) arriving in the input interface (17) comes from an external hard disk (15) such as for example the hard disk of a PC connected to the decoder unit (20).
• the main stream modified at the input of the interface (17) comes from a physical medium (CD, DVD or other storage element) (71) burned at the output of the server (4) with the information of the modified main stream (31) and transmitted to an external reader (18).
• the physical medium (71) is read by a reader (16) integrated in the housing (20).
• the modified main stream is first processed by the demultiplexer (12) and then stored in PES format in the hard disk (13) of the decoder unit.
• the modified main stream are 't previously stored in TS format or on a hard disk (the set-top box (13) or an external hard disk drive (15)) on a physical support (CD, DVD) before being demultiplexed.
• the main stream modified in PES format is sent to the temporary storage memory (10) via the transport bus (11).
• the additional information (51) is then transmitted on request to the decoder unit (20) via the network (6) and after having passed through the input interface (17) and the data bus (11), is stored partly in the temporary storage memory (10).
• the synthesis and descrambling device (8) recovers the parts of the modified main stream (31) and of the additional information (51) stored in the temporary storage module (10) and operates the descrambling in real time of the modified main stream .
• the additional information (51) arrives in real time via the network (6), the input interface (17) and the bus (11) as and when the synthesis device (8) needs it. All of the additional information (51) is not however never fully sent to the user.
• the synthesis device (8) sends it to the reader (9), which decodes it and then routes it to a viewing and hearing module (14) of the television screen type.
• the portal (4) has chosen the MPEG-2 TS stream (31) which it must send to the user's set-top box (20) to be watched on its television screen (14). This user is connected to a digital broadcasting network (7) and to an ADSL telecommunications network (6).
• the analysis and scrambling module (2) of the portal (4) therefore reads the incoming MPEG-2 TS (1) or MPEG-2 ES (1) stream, transforms it into an MPEG-2 PES stream, analyzes the contents of PES packets and each time it detects a PES packet to be modified, substitutes it with a PES "decoy" packet, which is the same size as the substituted video and audio packet.
• the analysis and scrambling module (2) then writes each true PES packet into the buffer (5) and continues its analysis until the end of the MPEG-2 input stream, in order to select the following PES packets to edit.
• the analysis and scrambling module (2) also registers in the buffer containing the additional information (51) information making it possible to locate the modified packet in the PES stream.
• the analysis and scrambling module (2) also registers in the buffer containing the additional information (51) instructions and data describing modifications to be made on the PES packets which follow the substituted packet .
• the new modified MPEG-2 stream is then converted into MPEG-2 TS format to be broadcast on the broadcasting network via the link (7) and recorded in the output buffer (3).
• the substituted PES packets of the incoming MPEG-2 stream (1) are stored in the buffer (5) of the portal (4).
• the new MP ⁇ G-2 stream The modified file is converted into MPEG-2 TS format to be recorded on a disc (71) of CD or DVD type.
• the CD or DVD (71) thus created will be read at the time of viewing the stream, by the decoder (20) via the internal reader (16) or via the external reader (18).
• the protected MPEG-2 stream is broadcast to a set of users (20).
• the phase described above corresponds to the first phase of preparation of the MPEG-2 stream by the portal (4), its transmission via the broadband network (7) and its recording in a decoder (20).
• This decoder can then, after processing, display this MPEG-2 PES stream recorded on its hard disk (13).
• the synthesis system (8) of the decoder (20) reads the MPEG-2 PES file from its hard disk (13), and sends it to a conventional MPEG-2 player (9).
• the MPEG-2 PES stream which reaches the player (9) is processed, displayed and listened to as is, which causes significant distortion of sound and the display on the television (14).
• the modified PES packets which are processed by the synthesis module (8) do not correspond to the PES packets which are necessary for correct visualization and hearing, since some of these PES packets have been replaced by random value packets.
• the reader (9) makes no difference and restores the information on the output screen (14) which appears well as data of a stream audio / video MPEG-2 PES but totally inconsistent for the eye and the ear of the human being who looks at the television screen (14) and listens to the sound.
• Any copy of the MPEG-2 TS stream coming from the hard disk (13) of the box (20) will produce the same audiovisual effect when it is reproduced by any MPEG-2 player.
• the synthesis module (8) then makes a request to the hard disk (13) and the data read is temporarily stored in the input buffer (10).
• the synthesis module (8) then establishes a link with the portal (4) via the telecommunications network (6) which is in our example an ADSL link. Once this connection has been established, and for the entire duration of viewing the film or the audiovisual program, the synthesis module (8) sends buffer memory
• the synthesis module (8) identifies the packages to be modified using the location data contained in the additional information (51).
• the PES packets are read and their location in the stream is obtained by reading their header.
• the additional information contains, in addition to the original PES packets, instructions on actions to be performed on the packets to be followed, for example inversion of certain well-selected bits in a part of the packets which follow.
• the synthesis module (8) reconstitutes inversely the analysis process and scrambling described above, the original MPEG-2 PES stream and sends the thus reconstructed MPEG-2 PES stream to the player (9) to be displayed on the screen (14) and played correctly.
• the original PES packets originating from the portal (4) constituting said additional information (5) are deleted from the synthesis system (8).
• the portal (4) before the portal (4) sends the original PES packets and associated data from its buffer (5), the portal (4) has verified that the user of the box (20) is indeed authorized to receive said information complementary .
• the modified main stream (5) is passed directly via a network (7) to the input interface (17), then is passed through the bus (11) to the buffer memory (10) and the synthesis module (8).
• the modified main stream (31) is written (recorded) on a physical medium such as a CD-ROM, DVD, hard disk, flash memory card, etc. (71).
• the modified main stream (31) will then be read from the physical medium (71) by the disk drive (16) of the housing (20) or by the external disk drive (18) to be transmitted to the read buffer (10) then to the synthesis module (8).
• the additional information (51) is recorded on a physical medium (52) of credit card format, consisting of a smart card or a flash memory card.
• This card (52) will be read by the module (17) of the device (20) which includes a card reader (61).
• the card (52) contains the applications and the algorithms which will be executed by the synthesis module (20).
• the device (20) is an autonomous, portable and mobile system.
• This preferred embodiment applies to audiovisual streams originating from the MPEG-2 standard and also to all normalized or standardized digital formats such as MPEG-1, MPEG-4, H262, H264, as well as to digital formats generating packets of private data, that is to say that the security process applies to all digital formats, for example but not only, to those regulated by the "Systems" part of the MPEG-2 standard (ISO / IEC 13818 -1).

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• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Databases & Information Systems (AREA)
• Computer Security & Cryptography (AREA)
• Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
• Data Exchanges In Wide-Area Networks (AREA)
• Television Signal Processing For Recording (AREA)

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• 2003
  • 2003-05-02 FR FR0350139A patent/FR2854530B1/fr not_active Expired - Fee Related
• 2004
  • 2004-04-30 EP EP04760477A patent/EP1621009A1/de not_active Withdrawn
  • 2004-04-30 MX MXPA05011744A patent/MXPA05011744A/es not_active Application Discontinuation
  • 2004-04-30 WO PCT/FR2004/050178 patent/WO2004100532A1/fr not_active Application Discontinuation
• 2005
  • 2005-11-02 US US11/264,953 patent/US7613181B2/en active Active
• 2009
  • 2009-09-24 US US12/566,426 patent/US8270402B2/en not_active Expired - Lifetime

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