Patent ID: 6658383
Filing Date: 2003-12-02
Classification: G10L

Abstract:
A method for decoding a portion of a coded signal, the portion comprising a coded speech signal or a coded music signal, the method comprising the steps of:determining whether the portion of the coded signal corresponds to a coded speech signal or to a coded music signal; providing the portion of the coded signal to a speech excitation generator if it is determined that the portion of the coded signal corresponds to a coded speech signal, wherein an excitation signal is generated in keeping with a linear predictive procedure; providing the portion of the coded signal to a transform excitation generator if it is determined that the portion of the coded signal corresponds to a coded music signal, wherein an excitation signal is generated in keeping with a transform coding procedure, wherein the coded music signal is formed according to an asymmetrical overlap-add transform method comprising the steps of: receiving a music superframe consisting of a sequence of input music signals; generating a residual signal and a plurality of linear predictive coefficients for the music superframe according to a linear predictive principle; applying an asymmetrical overlap-add window to the residual signal of the superframe to produce a windowed signal; performing a discrete cosine transformation on the windowed signal to obtain a set of discrete cosine transformation coefficients; calculating dynamic bit allocation information according to the input music signals or the linear predictive coefficients; and quantifying the discrete cosine transformation coefficients according to the dynamic bit allocation information; and switching the input of a common linear predictive synthesis filter between the output of the speech excitation generator and the output of the transform excitation generator, whereby the common linear predictive synthesis filter provides as output a reconstructed signal corresponding to the input excitation.