1. A transmission method for transmitting video data over a powerline communications transmission channel, a first communication device obtaining video data in the form of a succession of uncompressed images, the first communication device performing: performing a wavelet-decomposition of each uncompressed image, the wavelet-decomposition enabling obtaining data with different resolutions; performing a compression of each wavelet-decomposed image; transmitting, in pulse form with spreading, of each compressed image to a second communication device, so as to introduce data redundancy, the rate of which, for each data item in said compressed image, is defined according to the resolution of said video data item, the redundancy of the data with the lowest resolution being greater than the one of the data of any other resolution; dividing the succession of uncompressed images into uncompressed image sequences, by detecting changes in scenes on the basis of differences in luminance histograms between two consecutive images; determining speed maps representing the motion of the pixels of an uncompressed image to a following uncompressed image in the same sequence of uncompressed images; transmitting the obtained speed maps to the second communication device to enable said second communication device to apply an image enhancement operation by inter-image interpolation for at least one sequence of reconstructed images, on the basis of said speed maps; and determining the capacity of the powerline communications transmission channel and implementation of the compression of each wavelet-decomposed image, according to the determined capacity of the powerline communications transmission channel; and wherein, for determining the speed maps, the first communication device applies a sum of absolute differences algorithm to each sub-band of each resolution level, and determines a speed map, for each resolution level, from the results of applying the sum of absolute differences algorithm to each sub-band of said resolution level.