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:
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:
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 method of transmitting data packets associated with an importance level comprises a step (305) of estimating available rate on the network. In case a variation is detected in estimated available rate greater than a first predetermined value, determination is made (309-317) of whether there is an increase in the round trip time on said network that is greater than a second predetermined value. If yes, the data packets are transmitted (319-325) at a rate lower than the estimated available rate.In embodiments, in case a variation is detected in estimated available rate greater than a first predetermined value and before the step of detecting an increase in the round trip time, a step (307) is carried out of transmitting packets of lower importance level than the average of said importance levels by using the current estimated available rate and the round trip time is determined on the basis of the sending of those packets.
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:
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 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:
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:
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:
An encoder extracts motion vectors from a frame I(t−1) preceding the frame I(t) being encoded and processes them to create an estimated motion vector field I(t) for the frame being encoded. A minimized difference between the motion vector field of the frame being encoded and the estimated motion vector field is used to generate transform parameters, which are transmitted to the decoder as auxiliary information along with the usual motion prediction information. The decoder receives the transform parameters. The decoder also creates an estimated motion vector field I(t) for based on a preceding frame I(t−1) and applies the transform parameters to the estimated motion vector field to obtain missing motion vectors. The motion vector field rebuilt using the reconstructed missing motion vectors is used for subsequent error concealment/decoding/displaying.