Method for adapting for an interoperability between short-term correlation models of digital signals

The invention relates to the code conversion of digital signals, particularly voice signals, and in particular coding according to a second format from information obtained by carrying out a coding according to a first format. These first and second formats use LPC (linear predictive coding) short-term prediction models on digital signal sample blocks while using filters represented by respective LPC coefficients. The LPC coefficients of the second format are determined from an interpolation on the representative values of the LPC coefficients of at least the first format, between at least one given block and a preceding block. According to the invention, the interpolation, is dynamically effected while selecting, for each current block, at least one interpolation factor (α) among a preselection of factors according to a predetermined criterion such as a stationarity criterion of the digital signal.