Abstract: A video stream is digitally encoded such that the rate at which individual segments of data are encoded varies according to the amount of data required to generate each segment. Frames are selectively omitted from transmission (32) such that the cumulative frame rate does not fall below a predetermined value. This process can be used to ensure that the next frame to be displayed is always available in the buffer store 6 associated with the decoder (2). The decoder (2) is arranged to identify where frames have been omitted from the decoded transmission, and to perform a resynchronisation (7) on the decoded stream by comparison between time stamps in the video stream and a corresponding audio stream. Resynchronisation may be performed by extending the durations of individual frames, or by repeating frames.

Abstract: A preferred data provider is selected from a plurality of data providers by receiving a request for data from a client together with client identification data, identifying a plurality of data providers capable of providing data to the client, providing the client identification data to the data providers and instructing the data providers to perform tests in order to establish a measure of the elapsed time for a signal to be sent to and received from the client, and a measure indicative of their remaining capacity for data transfer, and to make these measures available to the system. One or more preferred data providers may then be selected on the basis of the elapsed time signals and the remaining capacity signals from the data providers.

Abstract: A foreground object part is distinguished from a substantially static background part of each videoframe within a video sequence. Each video frame is divided into a number of video blocks each of which comprises one or more pixels. A mask frame is generated in respect of each video frame, each mask frame having a mask block corresponding to each video block in each respective video frame. Each mask block is then set to either an object value, indicating that the corresponding video block in the corresponding video frame includes one or more pixels depicting a foreground object part, or to another value.

Abstract: A video sequence (4) is subjected to a signal compression process, in which the video sequence is divided (14) into a plurality of segments such that in each segment the number of bits required to code each frame in uncompressed form falls within a range having a predetermined magnitude, and a quantisation level is selected (17) for the encoding (19) of each segment such that the overall bit rate of the segment corresponds to a predetermined value. This value may be pre-set, or may be set in response to an input from the transmission network (3) or remote decoder (2). The quantisation level Q is determined according to a function of the number of bits per frame R, determined by analysis (10,11,12,13) of the entire sequence prior to transmission.

Abstract: A video stream is digitally encoded such that the rate at which individual segments of data are encoded varies according to the amount of data required to generate each segment. Frames are selectively omitted from transmission (32) such that the cumulative frame rate does not fall below a predetermined value. This process can be used to ensure that the next frame to be displayed is always available in the buffer store 6 associated with the decoder (2). The decoder (2) is arranged to identify where frames have been omitted from the decoded transmission, and to perform a resynchronisation (7) on the decoded stream by comparison between time stamps in the video stream and a corresponding audio stream. Resynchronisation may be performed by extending the durations of individual frames, or by repeating frames.

Abstract: A system (20) and method by virtue of which a preferred data provider is selected from a plurality of data providers (30) by performing the steps of receiving a request for data from a client (10) together with client identification data, identifying a plurality of data providers (30) capable of providing data to the client (10), providing the client identification data to the data providers and instructing the data providers to perform tests in order to establish a measure of the elapsed time for a signal to be sent to and received from the client, and a measure indicative of their remaining capacity for data transfer, and to make these measures available to the system (20). One or more preferred data providers (30) may then be selected on the basis of the elapsed time signals and the remaining capacity signals from said data providers.

Abstract: A file server (1) in communication with a remote client (e.g. PPC 7, Mobile phone client 5) receives images from a camera (2) or video store (4) as full frame images. A selection and compression programme enable the transmission of bit streams defining a compressed video image for display on the comparatively small screen of the mobile client and permits simple virtual zoom and frame area selection to be viewed by the user. Compression and selection algorithms enable the user to select an angle view having a corresponding number of pixels to the local screen but derived from the whole of the original frame and fully compressed and with varying selections of compression between down to selection by the file server (1) of a portion of the original frame having the same number of pixels.

Abstract: A method of distinguishing between a foreground object part and a substantially static background part of each videoframe within a video sequence. The method comprises the steps of: dividing each video frame into a number of video blocks each of which comprises one or more pixels; generating a mask frame in respect of each video frame, each mask frame having a mask block corresponding to each video block in each respective video frame; and either setting each mask block to either an object value, indicating that the corresponding video block in the corresponding video frame includes one or more pixels depicting a foreground object part, or to another value.