Snr scalable video encoding method and corresponding decoding method

For use in an STR scalable video encoder comprising, for allowing a progressive transmission of information, a base layer circuit capable of receiving an input stream of video images and generating therefrom compressed base layer video data suitable for transmission to a video decoder and at least an enhancement layer circuit capable of generating therefrom enhancement layer video data associated with the compressed base layer video data and suitable for transmission to the video decoder, an encoding method based on a hierarchical triangular mesh representation to which a matching pursuit error coding step is specifically adapted, said encoding method comprising the following steps:

• a base layer encoding step, provided for receiving a couple of reference and current images N-1 and N and a coarse mesh and encoding by means of a matching pursuit method the error residual image F, between the current image N and an associated motion compensated image Nci;
• a first enhancement layer encoding step, provided for receiving said current image and a reconstructed image N′ci obtained by adding to the motion compensated image Nci the motion residual image reconstructed from the coded error residual image εi, and for generating from the difference between said current image and said reconstructed image Nc′i a new error residual image ε′i used to refine the current level mesh “Mesh 1” towards a new mesh “Mesh 2” then taken as input for a further level, the information concerning the mesh distortion being contained in motion vectors MVi;
• at least another enhancement layer encoding step including similar receiving and generating operations;
• the matching pursuit method being applied during each encoding step to the error residual image εi in view of the transmission of the image texture information in the form of atoms.