1. A hierarchical coding method to give a flow of coded data, a first picture in format F 1 and a second picture in format F 2 of a lower resolution to the first format F 1 , video content of the first and second pictures having at least one common part, the method comprising the steps of: coding of the second picture to provide coded data for a base layer of the flow of coded data, zooming of the second picture to obtain a low resolution zoomed picture of dimensions of those of the first picture for the common part, wherein the first picture and the second picture have different non-proportional formats, coding of a picture zone of the common part to supply a picture of residues relating to the prediction picture, decoding the coded picture zone to provide a reconstructed common zone, coding of the first, high resolution picture image blocks of a non common part, to supply coded data to an upper layer of the coded data flow by using at least one of the following modes: predictive inter layer coding using a previous low resolution zoomed picture in which a predicted block and a motion vector defining the predicted block is determined, predictive inter layer coding using a current low resolution zoomed picture in which a predicted block and a motion vector defining the predicted block is determined, wherein the non-common part is coded using at least an inter-spatial coding mode consisting in using the reconstructed common zone as prediction picture to determine a predicted block.