Abstract: It is characterised in that it comprises: a) centring a mask in a spectral peak of a plurality of spectral peaks of a spectrogram of an audio signal; b) defining spectral regions around said spectral peak by means of said mask; c) capturing average energies of each of said spectral regions; d) comparing each of said average energies between them; e) obtaining a bit for each comparison, each obtained bit indicating the result of each comparison; f) grouping each bit obtained by means of said comparison in order to constitute an audio fingerprint; and g) encoding of the encoded spectral peaks using coarse frequency bands in order to allow for fast comparison of fingerprints