Patent ID: 8279944

Claim:
A method for regulating an encoding bit rate of video image sequences with regard to a target bit rate represented by a target image size, within the framework of an application to networked video surveillance, including remote control of a video surveillance camera from a host terminal by an operator, for each current image of rank p belonging to successive sequences of N images, 1≦p≦N, said video images being subdivided into a set of zones to be encoded, the estimated size of said set of zones to be encoded being a function of the size of the encoded zones, the estimated size of the zones to be encoded and an estimated encoding error of the zones to be encoded, wherein the method comprises at least, for each image, prior to any encoding of a zone: subdividing each current image into a set of N superimposed zones to be encoded, each constituted by a plurality of lines of pixels; discriminating, among the zones to be encoded of said set of zones to be encoded, an encoding complexity of each zone to be encoded, said encoding complexity of each zone to be encoded being defined as the estimated size in bytes occupied by said zone to be encoded after encoding, for a determined zone and image quality; classifying said zones to be encoded according to a determined order of complexity and choosing one of the zones to be encoded as a first zone to be encoded and applying an Intraframe encoding, with a minimum quantization step, in order to obtain a maximum encoding complexity for said first zone to be encoded; encoding in Interframe encoding an adjacent zone to be encoded immediately above said first zone, applying a reduced quantization step, in order to retain a fineness of encoding of this zone; encoding each of remaining zones to be encoded in Interframe encoding, according to the order of decreasing complexity classification, successively minimizing the estimated encoding error of each remaining zone to be encoded and the final size of said current image with regard to said target size and optimizing the bit rate of the sequence of video images, wherein the minimization of the estimated error comprises at least adapting successively a quantization step to be applied to the encoding of each zone to be encoded; and successively repeating above operations for each image of rank p+1 following said current image, choosing as first zone to be encoded one of the zones to be encoded having a rank different from the rank of the zones encoded as first zone to be encoded from the preceding p images, which makes it possible to retain the random access to the sequences of images.