Abstract:
The invention relates to a method for the secure distribution of digital still images in the form of streams comprising sequences of data, each containing part of the image information. The inventive method comprises a modification step involving the modification of the original stream, in which at least one part of the aforementioned data sequences is modified to produce a modified stream with the same nominal format as the original stream. The method also comprises a modified stream transmission step and a reconstruction step using a decoder on the recipient device. The invention is characterised in that the reconstruction is adaptive and progressive according to information originating from a digital profile of the recipient user. Moreover, the original stream is coded using a wavelet coding method. The above-mentioned modification produces a main modified stream and complementary information which enables the original stream to be reconstructed by a decoder. The method comprises a modified stream transmission step and a step involving the transmission of a subset of the complementary modification information to the recipient device, said subset being determined according to information originating from a digital profile of the recipient.
Abstract:
The invention relates to a method for secure distribution of fixed digital images according to a nominal format arising from digital coding in wavelets, represented by a stream consisting of at least one packet (relating to the organization of the binary sequence) containing at least one block including individual digitally coded elements according to a specific manner inside the stream concerned and used by all decoders able to retrieve or to decode it in order to display the image correctly. The inventive method comprises the following steps: a preparatory stage consisting in modifying at least one of said individual elements according to at least one substitution operation consisting in the extraction of said individual element, followed by the replacement thereof with dummy data; a stage of transmission of the main stream modified according to the nominal format, made up of blocks modified during the preparatory stage, and by a separate path of the main stream of additional digital information, enabling the original stream to be retrieved based on calculation on the target equipment according to the main stream and the additional information.
Abstract:
The invention relates to a method for the secure distribution of compressed digital texts comprising blocks of binary data and resulting from transformations applied to an original text. The inventive method comprises two steps, namely: a preparatory step consisting in modifying at least one binary datum in one of the aforementioned blocks using at least one substitution operation involving the extraction of said datum from a block and the replacement thereof with a decoy; and a step consisting in transmitting (i) a modified compressed digital text (5) that conforms to the format of the original text, comprising blocks that were modified during the preparatory step, and, over a separate channel from the modified compressed text (5), (ii) a piece of complementary digital information (4) which can be used to restore the original compressed digital text (1) on the destination equipment from the modified compressed digital text (5) and said complementary information (4). The invention also relates to a system which is used to implement said method.
Abstract:
The invention relates to a method and system which are used for the visual scrambling of a video sequence and for the reconstruction (descrambling) of the original content thereof from a digital video stream obtained from encoding based on a wavelet transform. The method for the secure distribution of video sequences according to a digital stream format stems from wavelet-based coding, said format consisting of frames comprising blocks containing wavelet coefficients which describe visual elements. According to the invention, before transmission to the client equipment, the stream is analysed in order to generate (i) a modified main stream through the removal and replacement of certain pieces of information encoding the original stream and having the same format as said original stream, and (ii) a complementary piece of information with any format, comprising digital information which encode the original stream and which can be used to reconstruct the aforementioned modified frames. The modified main stream and the complementary information thus generated are then transmitted separately from the server to the destination equipment and, subsequently, a synthesis of a stream with the nominal format is calculated on the destination equipment as a function of the modified main stream and the complementary information. The invention also relates to a system comprising at least one multimedia server containing the original video sequences, a video stream analysis device, a device for separating the original video stream into a modified main stream and a complementary piece of information according to the aforementioned analysis and at least one device on the destination equipment for the reconstruction of the video stream as a function of the modified main stream and the complementary information.
Abstract:
The invention relates to a method for securely distributing digital audio-visual flows according to a standard format which is normalised or proprietary. Prior to the transmission to a recipient device, said flows are divided into two parts in order to generate a modified main flow having the original flow format and supplementary digital information for reconstructing the original flow. Said invention is characterised in that the main modified flow is transmitted through separate channels from a distribution server during the distribution and said supplementary information is transmitted to the recipient device from a secured central server through a local server connecting said recipient device to said central server through at least one access point.
Abstract:
The invention relates to a method of distributing digital audio sequences according to a nominal stream format consisting of a series of frames. Each of said frames comprises a digital block containing a certain number of coefficients corresponding to simple audio elements which are digitally encoded according to a mode identified in the relevant stream and used by all of the audio decoders capable of doing so, such that the stream can be decoded correctly. The invention is characterised in that it comprises: a preparatory step consisting in modifying at least one of the aforementioned coefficients; and a transmission step involving the transmission of (i) a main stream with the nominal format, which is made up of the blocks modified during the preparatory step, and (ii), using a channel separate from said main stream, complementary digital information which enables the original stream to be reconstructed from the calculation on the recipient device according to the main stream and the complementary information. The invention also relates to a system and a piece of equipment which are used to implement the inventive method.
Abstract:
The invention relates to a method of distributing digital audio sequences in the form of streams comprising sequences of data containing digital audio blocks. The inventive method comprises a step involving the modification of the original stream, whereby at least one part of the aforementioned data sequences is modified, said modification producing a modified stream with the same nominal format as the original stream. The method also comprises a modified stream distribution step and a reconstruction step using a decoder. The invention is characterised in that the reconstruction of the original stream is adaptive and progressive according to the information originating from a digital profile of the recipient. In one particular embodiment, the modification step produces a modified main stream and complementary information which enables the original stream to be reconstructed by a decoder, the method comprising a modified stream distribution step and, in addition, a step involving the transmission of a subpart of the above-mentioned complementary modification information to the destination equipment, whereby the subpart is determined according to the information originating from a digital profile of the recipient. The invention also relates to a system for implementing said method.
Abstract:
The invention concerns a method for distributing video sequences which consists in broadcasting a main digital data stream and a complementary information required for viewing the video sequence, and in reconstituting at the reception site the video stream displayable on an equipment provided with a screen (6). The invention is characterized in that the reception site comprises a personal computer (1), mass storage means (10), a video processing peripheral equipped with means for communicating with the personal computer (1) and transmitting the displayable stream to the display device, the main digital data stream being received by the personal computer (1), the software application for reconstituting the display stream being executed in the video processing peripheral (2). The invention also concerns a decoder (1) and a system for implementing said method.
Abstract:
The invention relates to an automatic, adaptive method of scrambling digital video streams. The inventive method comprises the following steps consisting in: analysing the structure and the visual content of the digital video stream, and scrambling said digital video stream. The invention is characterised in that the scrambling step is controlled by an inference or decision-making engine which selects the scrambling tool(s) to be applied to the digital video stream from a library of possible scrambling tools, according to: the analysis step, digital information relating to the characteristics of the user for whom the resulting scrambled digital video stream is intended, and conditions for transferring the digital data resulting from said method in compliance with a database of pre-defined scrambling rules.
Abstract:
The invention relates to a method of distributing digital audio sequences according to a nominal stream format, said sequences consisting of a succession of frames each comprising at least one block containing numerous coefficients corresponding to simple digitally-encoded auditory elements. According to the invention, the method comprises a step involving the modification of at least one block of the original stream. The invention is characterised in that the aforementioned modification step acts in an adaptive manner in relation to the original stream according to at least one part of the characteristics representative of the structure, contents and parameters of the original audio stream and the profile of the recipient as well as external events. In one particular embodiment, the modification step consists in replacing part of the coefficients in order to produce (i) a main audio stream with the nominal format and (ii) complementary modification information which enables the original stream to be reconstructed by a decoder belonging to the destination equipment, the range of the modifications being variable and determined by the above-mentioned representative characteristics. The invention also relates to a system for implementing said method.