| 摘要 |
The invention relates to a method for determining an optimized scale factor to be applied to an excitation signal or to a filter during a process for frequency band extension of an audiofrequency signal, the band extension process (E601) comprising a step of decoding or extracting, in a first frequency band, an excitation signal and parameters of the first frequency band including the coefficients of a linear prediction filter, a step of generating an excitation signal extending over at least one second frequency band, and a step of filtering by means of a linear prediction filter for the second frequency band. The determination method comprises the steps of determining (E602) a linear prediction filter referred to as an additional filter, of a lower order than that of the linear prediction filter of the first frequency band, the coefficients of the additional filter being obtained from the parameters decoded or extracted from the first frequency band and calculating (E603) the optimized scale factor as a function of at least the coefficients of the additional filter. The invention also relates to a device for determining an optimized scale factor using the method as described and to a decoder including such a device. |
