Entropy and data compression performances

Summary form only given. We describe a simple algorithm, based on the original Shannon formulation, to determine the entropy orders of an input file. Furthermore we analyse some properties relative to the entropy orders evaluated. Finally a general preprocessing method is sketched. The goal of this module is to reduce the running time and waste of computational resources relative to the data compression. The is to attempt to answer a more general question. Is it possible to predict the data compression performance of any compressor only on the basis of the complete knowledge of the data entropy?