1. A computer-implemented method for processing a signal, said method comprising: receiving a first block of samples of the signal; applying butterfly coefficients to the first block of samples determined by a given window function to produce resulting vectors; storing a portion of the resulting vectors in a memory of a one block delay buffer and recovering current contents of the delay buffer; mapping the input signal with the applied butterfly coefficients to a cascade of butterflies using a first set of weights and reordering the cascade of butterflies; computing a spatial transform from the reordered cascade of butterflies to produce transform coefficients; and combining the transform coefficients to produce an encoded output corresponding to the input signal.