Abstract: A communication system includes a plurality of nodes, the communication system being arranged to assign each of the plurality of nodes a certificate by means of which it can authenticate itself to other nodes in the communication system. The communication system further includes an authentication node arranged to determine that a certificate should be revoked and to, responsive to that determination, write an indicator of that certificate's revocation to a location in the communication system that is external to the authentication node and to which the node assigned the revoked certificate is not permitted to write.

Abstract: A method of controlling communication quality between one node and at least one other node in a packet switched communication system, the method comprising the steps of detecting at one of said nodes a condition that indicates that communication quality is below an acceptable threshold, automatically generating instructions based on the detected condition for a user of the at least one node, said instructions intended to provide a remedy to improve the communication quality, and receiving input from a user of the at least one node responsive to the instructions to implement the remedy and thereby improve the communication quality.

Abstract: A method of placing an outgoing communication event to a destination phone number is disclosed. Accordingly, upon receiving a notification of the outgoing communication event, a determination is made if the destination phone number is associated with a user of a first network. The first network is a packet based communication network. A user identification of the user of the first network corresponding to the destination phone number is then retrieved. A presence information of a communication node in the first network associated with the user is also retrieved. The presence information is an indication of the user's availability. The communication node is configured to receive voice communication events. The outgoing communication event to the communication node associated with the user in the first network is placed based on the retrieved presence information.

Abstract: A first network comprising: one or more first end-user computer terminals; a gateway to a second, packet-based network comprising one or more second end-user computer terminals installed with a communication client of the second network; one or more telephone units for performing calls with one of the second end-user computer terminals over the second network; wherein each of the one or more first end-user terminals is installed with a communication client for performing calls with the second end-user computer terminals over the second network; and wherein the gateway comprises switching apparatus configured to detect a user selection between a first state in which one of said calls is to be performed using one of said first end-user computer terminals and a second state in which the call is to be performed using one of said telephone units; and on condition of detecting the first state, to route both call set-up signaling and call media to the first end-user computer terminal; and on condition of detecting t

Abstract: According to an embodiment, a method of reducing noise in a signal received at a processing stage of an acoustic system includes, at the processing stage identifying at least one frequency which causes a system gain of the acoustic system to be above an average system gain of the acoustic system; providing a noise attenuation factor for reducing noise in the signal for the at least one frequency, the noise attenuation factor for the at least one frequency based on the system gain for that frequency; and applying the noise attenuation factor to a component of the signal at that frequency.

Abstract: A method of altering a caller line identification in a phone service is disclosed. The method includes receiving, via a user interface, a phone number from a user of the phone number. A to-be called phone number is then selected from a pool of phone numbers. The to-be called phone number is temporarily associated with the phone service for a selected period of time. The to-be called phone number is displayed on the user interface. Via the user interface, the user is requested to call back the displayed to-be called phone number within the selected period of time.

Abstract: A method comprising: for each target image portion to be encoded in a frame, selecting one of a set of encoding modes by optimizing a function comprising an estimate of distortion for the target image portion and a measure of bit rate required to encode the target image portion, encoding the target image portion into the encoded video stream using the selected mode. The encoded video stream is transmitted over a lossy channel. An error propagation distortion map is maintained, which comprises a plurality of error propagation distortion values mapping to respective frame partitions, the error propagation distortion values being based on previous encoding mode selections. The estimate of distortion used to select the encoding mode for each of the target image portions is based on a corresponding portion from the error propagation distortion map, and that corresponding portion is constrained to being co-located with the target image portion.

Abstract: A method of establishing communication between a first and second user over a communications network, the second user being associated with contact information for at least one destination node. The method comprises allocating the contact information for the at least one destination node an identity from a set of available identities and displaying a hyperlink containing the identity on a display, wherein the hyperlink does not contain the contact information of the second user. The method also comprises the first user viewing the display using a terminal connected to the communications network and activating the hyperlink, and responsive to activating the hyperlink, transmitting from a client executed on the terminal a message to initiate communication, the message comprising the identity.

Abstract: A signal to be transmitted from a terminal via a channel in a communication network is encoded by receiving the signal at the terminal; determining characteristics of the channel; encoding a first portion of the signal in accordance with a first encoding method to produce a first encoded signal portion; and encoding a second portion of the signal in accordance with a second encoding method to produce a second encoded signal portion. The first portion of the signal is encoded in accordance with the first encoding method depending on the determined characteristics of the channel. The first encoded signal portion and the second encoded signal portion are transmitted via the channel.

Abstract: Method, relay node and computer program product for processing transport packets, the transport packets conveying: (i) data stream units forming a data stream, and (ii) correction data units relating to the data stream units, where each transport packet contains information identifying the content of units in that transport packet. Transport packets are received at the relay node, the data stream units in the transport packets received at the relay node being insufficient to constitute the data stream. At least some of the correction data units and the data stream units in the received transport packets are used to generate substitute data stream units thereby to substantially recover the data stream at the relay node. The relay node packetises the data stream units of the substantially recovered data stream with correction data units to form output transport packets for transmission from the relay node, and then the output transport packets are transmitted from the relay node.

Abstract: A method and computing system for suppressing noise in an audio signal, comprising: receiving the audio signal at signal processing means; determining that another signal is input to the signal processing means, the input signal resulting from an activity which generates noise in the audio signal; and selectively suppressing noise in the audio signal in dependence on the determination that the input signal is input to the signal processing means to thereby suppress the generated noise in the audio signal.

Abstract: A system comprising: one or more first user terminals each for a respective user, each of the first user terminals comprising a first interface to a service run over a communication network; an authorization mechanism arranged to conditionally verify the users of the first user terminals as being licensed to use the communication service based on a first indication received via the first interface; and one or more second user terminals each for a respective user, each of the second user terminals comprising a second, alternative interface to the communication service; wherein the second interface is not operable to provide the first indication to the authorization mechanism; and wherein the authorization mechanism is configured to conditionally verify the users of the second user terminals as being licensed to use the communication service based on a second indication received via the second interface.

Abstract: Method, terminal, network and computer program product for processing updates of an image for transmission from a first terminal to a second terminal for use in screen sharing between the first terminal and the second terminal wherein updates to the image displayed on a first display at the first terminal are also displayed on a second display at the second terminal. The image is divided into an array of contiguous sub-tiles, each sub-tile comprising more than one picture element of the image. It is determined that a plurality of sub-tiles of the image have changed at the first terminal and at least one of said changed sub-tiles and at least one contiguous sub-tile are selected to form a tile.

Abstract: Some embodiments describe methods, programs, and systems for speech encoding. Among other things, a received input signal representing a property of speech is quantized to generate a quantized output signal. Prior to the quantization, a version of the input signal is supplied to a first noise shaping filter having a first set of filter coefficients effective to generate a first filtered signal. Following the quantization, the quantized output signal is supplied to a second noise shaping filter having a second set of filter coefficients, thus generating a second filtered signal. A noise shaping operation is performed to control a frequency spectrum of a noise effect in the quantized output signal caused by the quantization, wherein the noise shaping operation is based on both the first and second filtered signals. Finally, the quantised output signal is transmitted in an encoded signal.

Abstract: Method, device and computer program product for transmitting a video signal from a user device includes capturing a plurality of frames of the video signal using a camera at the user device, determining a functional state of the device and selectively stabilizing the video signal prior to transmission based on the functional state.

Abstract: The present invention provides a method of processing video data in a video communication system, and a corresponding program and apparatus. The method comprises: receiving first video data at a first terminal from a second terminal; generating second video data at the first terminal for transmission to the second terminal; selecting the size of a first video area for displaying the first data within a display area; and scaling the first video data to the selected size of the first area and displaying it therein. The method further comprises: determining a second video area for displaying the second data within the display area, the determination of the second area comprising at least determining a location of the second area relative to the first area in dependence on the size of the first area; and scaling the second video data to the second video area and displaying it therein.

Abstract: A method of processing an audio signal transmitted from a remote transmitter and received at a local receiver of an acoustic system, includes at the receiver receiving with the audio signal an indication of remote transmitter gain, determining an overall system gain of the acoustic system from the remote transmitter gain and a local receiver gain and selectively applying a system gain reduction step to the audio signal if it is determined that the overall system gain exceeds a threshold.

Abstract: A television appliance comprising: a television receiver for receiving television signals and outputting the television signal of a selected channel to a screen; a network interface for accessing a packet-based network; a memory storing a communication client application; and processing apparatus arranged to execute the communication client application. The client application is configured to maintain a list of contacts and allow a user of the media appliance to establish communication events with the contacts via the network interface and packet-based network.

Abstract: Method, device and computer program product for stabilizing a video signal. A plurality of frames of the video signal are captured using a camera. A motion sensor associated with the camera is used to generate a plurality of samples representing motion of the camera. The samples are used to determine a displacement of the camera between a first time and a second time, wherein the first time corresponds to an exposure time midpoint of a first frame of the video signal and the second time corresponds to an exposure time midpoint of a second frame of the video signal. The determined displacement is used to compensate for motion in the video signal between the first and second frames caused by the motion of the camera, to thereby stabilize the video signal.

Abstract: A method of establishing a communication event in a communication system from an initiator device to one of a plurality of entities associated with the initiator device comprising assigning a calling identity to at least one of said entities at a first network node associated with a packet switched network; providing the assigned identity to the initiator device; storing associated contact information for the entity together with the calling identity assigned to the entity at a second network node associated with the packet switched network, initiating a communication event from the initiator device to the entity via a circuit switched network by transmitting the identity assigned to the entity to a gateway node; sending a message to the second network node with the identity assigned to the entity to determine the contact information for the entity; and routing the communication event from the gateway node to the entity using the determined contact information via one of the circuit switched and packet switch