Abstract: The invention concerns a method of notifying control information to a congestion control mechanism in charge of controlling data segments sending rate of a server towards a client. The control information includes loss events where a loss event corresponds to one or more data segments lost. The method comprises a step of receiving data segments into a reception buffer at the client, a step of detecting loss events from the received data segments and a step of notifying the congestion control mechanism with a number of loss events that is dependent on the number of detected loss events and a measure of criticality related to the reception of the data segments by the client. The measure of criticality can be derived from the filling level of the reception buffer, the reception of data segments being in a critical state when the reception buffer is experiencing overflow or underflow conditions.

Abstract: To predict the transmission error rate in a stream of data packets transmitted between a server and at least one client in a communication network: the server sends at least one group of packets to the client; the client calculates a plurality of items of statistical information on the group of packets and transmits them to the server; the server analyzes the items of statistical information so as to obtain a network stability indicator; and the server calculates a prediction of the transmission error rate on the basis of the network stability indicator.

Abstract: In order to share digital data in a peer to peer communication network, a partial version of the data is firstly transmitted to destination stations, and: a collection of data is created in which an identifier is associated with each data item and to each data identifier there is allocated a label indicating whether the complete version of the data item is available on the network; the existence of the collection is notified to at least one destination station; and, on the reception of information on availability on the network of the complete versions of the data of the collection: the collection is updated; and the updating of the shared collection is notified to the destination station or stations.

Abstract: In a method of encoding a video frame to be transmitted to a plurality of clients over a plurality of network connections, a set of parameters is associated with each connection. The method comprises: for each connection, determining a frame size that can be transported over the connection considering the associated set of parameters; and compressing the video frame to a target frame size based on the minimum of the plurality of determined frame sizes. This method advantageously provides an easy and straightforward way for selecting the appropriate parameters that need to be taken into account for controlling the rate of the generated bitstream, particularly when multiple parameters are associated with each connection.

Abstract: The invention relates to a method for transmitting over a data communication network data packets of a data stream to a receiving device, characterized in that it comprises the steps of: selecting a data packet from a buffer memory containing data packets to be transmitted (301, 401); determining whether the playout time of the selected data packet at the receiving device allows a recovery of said selected data packet (303, 410); assigning a first priority level or a second priority level to the selected data packet based on the result of the determining step (306, 307, 411, 413); and transmitting the selected data packet with said assigned first or second priority level (308, 408). The invention relates also to a software application and a transmitting device implementing the transmission method.

Abstract: The invention relates to a method of managing the quantity of data transmitted by a transmission device over a telecommunication network, characterized in that the method comprises the steps, carried out by the transmission device, of: obtaining (E503), for at least a first and second data set that have to be transmitted over the telecommunication network, the quantity of data within each data set and the time constraint on each data set; determining (E504) the bitrate for transmission of the first data set in accordance with the time constraint on the first data set; determining (E504) the bitrate for transmission of the first and second data sets in accordance with the time constraint on the second data set; and selecting (E504) the maximum of the determined bitrates as a parameter for managing the quantity of data transmitted by the transmission device.

Abstract: A method for adapting error protection in a communication network includes: a step of determining periods of time that are homogeneous as regards the distribution law of losses over the network, a step of classifying the homogeneous periods of time into at least two classes, on the basis of information representing losses over the network and/or representing a corresponding level of protection, during these periods of time, a step of determining a probability of alternation between two of said classes, and a step of selecting a protection strategy on the basis of said probability of alternation. A method of detecting transition between two states of a communication network corresponding to different loss rates of sent data includes: a step of determining a probability of transition, and a step of determining the existence of a transition on the basis of said probability.

Abstract: The method of computing the available space in a packet for data stream transport comprises: a step of determining the requirements of each module of a data stream manager, for space in the packet for at least two types of header and/or extension data required by each protocol and/or service used by said module, a step of determining a maximum space requirement in the packet to meet all these requirements, by implementing different rules for combining space requirements for the different types of data and a sum of the combined requirements for the different types of data and a step of computing a difference between the space of the packet and the maximum space requirement in the packet in order to determine the available space for data stream transport.

Abstract: A central server in a network of a hybrid peer to peer type, receives a request from a client for obtaining a digital document, where the request contains a reference of the digital document. The server selects a peer system of the network likely to contain the digital document, and generates an access key for controlling access to the digital document by the client, where the access key is generated by an encrypting method using a private key of the central server, a current time when the encrypting method is executed and an address of the client on the network. The server then sends a message to the client, where the message has the reference of the digital document, an address of the selected peer system on the network and the generated access key.

Abstract: The access method comprises the following steps: selecting a first data item in a digital document designated by a predetermined identifier, said digital document comprising at least first and second data items linked to each other in a chosen hierarchical relationship; verifying the presence of at least one address of a location containing said second data item of the digital document in storage means of the client device; in the absence of said address in said storage means, seeking said address in the network; in the event of a positive search, storing said address in the storage means of the client device; and subsequently accessing said second data item of the document from the address thus stored by anticipation and thus immediately available locally.

Abstract: A method of sending a data stream of video images between a server and at least one client device in a communication network, employing a rate setting for the sending of data over the communication network, the method comprising the following steps: obtaining (910) an item of information Pc representing a speed of variation over time for a rate setting, said item of information depending on at least one characteristic of the state of the traffic over the communication network, comparing (920) said item of information Pc so obtained with a scheduled time Ev for a set of video image data to send, adapting (930) the rate setting delivered by the server on the basis of at least the result of the comparing step, compressing said set of video image data to send using a compression mode which depends on the adapted rate setting, sending said set of video image data so compressed.

Abstract: The invention relates to a central server stations controlling access to a collection of digital data created by a client station. The server station receives, from the client station, a request to validate a collection of digital data, where the request contains the collection which has a collection identifier and for each data item belonging to the collection, a data identifier designating said data item, and at least one representation of said data item, the representation being chosen depending on said data item and on the collection identifier. For each data identifier received, a representation of the data item is locally obtained depending on the data item and on the collection identifier of the received collection associated with the collection. A comparison is made between the received representation and the obtained local representation and, in a case where the comparison results in a match, the digital data item to be shared is validated.

Abstract: The invention concerns a method of correcting errors in a data stream of at least one image, implemented in a data reception device, said at least one image being cut up into image portions, said stream being coded by image portion and divided into data packets, the method comprising a step of detecting at least one lost data packet and being characterized in that it comprises the following steps: determining a strategy for cutting up said at least one image into image portions, determining, according to the determined cutting-up strategy, an item of information representing the reconstruction quality of data included in said at least one lost packet by an error correcting method, adapting said error correcting method according to the determined item of information representing the reconstruction quality, and applying the adapted error correcting method to the adapting step to reconstruct the data included in said at least one lost packet.

Abstract: A method of allocating at least one service by a first peer (E) to a second peer (D), the peers being linked by means of a computer communication network, the first and second peers belonging respectively to a first and second group of peers adapted to share data, comprises the following steps: evaluating (E63) a distance (d0) between the first peer (E) and the second peer (D); and selecting (E65) a service allocated by the first peer (E) according to the value (d0) of the distance.

Abstract: The access method comprises the following steps: i) receiving a notification indicating the presence of at least one digital document available on the network, said notification comprising at least one executable command adapted to detect whether the recipient client device comprises a local application capable of processing the digital document, ii) executing the command or commands in order to detect the local application, and iii) in case of positive detection, accessing the digital document from a local server whereas in case of negative detection, accessing the document from the address of a remote server.

Abstract: To predict the transmission error rate in a stream of data packets transmitted between a server and at least one client in a communication network: the server sends at least one group of packets to the client; the client calculates a plurality of items of statistical information on the group of packets and transmits them to the server; the server analyzes the items of statistical information so as to obtain a network stability indicator; and the server calculates a prediction of the transmission error rate on the basis of the network stability indicator.

Abstract: The invention relates to a method for transmitting over a data communication network data packets of a data stream to a receiving device, characterized in that it comprises the steps of: selecting a data packet from a buffer memory containing data packets to be transmitted (301, 401); determining whether the playout time of the selected data packet at the receiving device allows a recovery of said selected data packet (303, 410); assigning a first priority level or a second priority level to the selected data packet based on the result of the determining step (306, 307, 411, 413); and transmitting the selected data packet with said assigned first or second priority level (308, 408). The invention relates also to a software application and a transmitting device implementing the transmission method.

Abstract: A video consisting of data organized in the form of a plurality of images is transmitted in a communication network. The method comprises a step of coding images with motion compensation, which consists in compressing the images of the video and in creating dependencies between compressed images, a step of scheduling the transmission of packets representing the compressed images, which consists in sending the compressed images over the network in a selected order, and a step of controlling the rate of the video. At least one of reconsidering the selected order of sending already compressed but not yet transmitted images and deleting at least one compressed image is performed at the time of coding a new image. Furthermore, the dependencies between the new image to be compressed and the compressed images are selected by taking into account the reconsidered sending order at the time of coding the new image.

Abstract: A method of processing a coded data stream of a current image on a receiving device, the data stream being organized into packets, comprises a step of detecting a lost packet. It further comprises: a step of estimating, prior to the decoding of the current image, an importance criterion of the lost packet, the importance criterion being determined from at least one decoded preceding image; and a step of requesting retransmission of the lost packet depending on said estimated importance criterion. Use in particular for improving the transmission of a video.

Abstract: The invention relates to a method of managing the quantity of data transmitted by a transmission device over a telecommunication network, characterized in that the method comprises the steps, carried out by the transmission device, of: obtaining (E503), for at least a first and second data set that have to be transmitted over the telecommunication network, the quantity of data within each data set and the time constraint on each data set; determining (E504) the bitrate for transmission of the first data set in accordance with the time constraint on the first data set; determining (E504) the bitrate for transmission of the first and second data sets in accordance with the time constraint on the second data set; and selecting (E504) the maximum of the determined bitrates as a parameter for managing the quantity of data transmitted by the transmission device.