Patent ID: 7603559

Claim:
An apparatus comprising: an input into which an audio-visual signal is fed from a capture device, said signal being comprised of a plurality of sequential frames, each of said plurality of sequential frames being comprised of at least first and second frames portions; a memory connected with the input for sequential storing each of the at least first and second frames portions of each of the frames of said audio-visual signal, thereby allowing for a reduced memory requirement relative to storing an entire frame of said audio-visual signal; a processor programmed to perform the step of: calculating a signature based on a first portion of said frame of said audio-visual signal currently stored in the memory, embedding the signature calculated based on the first frame portion in the second frame portion stored in the memory subsequently to the first frame portion such that the signature is frame from which it is calculated, while the second frame portion is stored in said memory, calculating a signature based on the second frame portion for embedding in a subsequent frame portion to be stored in the memory subsequent to the second frame portion; and an output from which the frames with the embedded signature are outputted.