Scalable Encoding Device and Scalable Enconding Method

摘要

There is provided a scalable encoding device capable of realizing a bandwidth scalable LSP encoding with high performance by improving the conversion performance from narrow band LSPs to wide band LSPs. The device includes: an autocorrelation coefficient conversion unit ( 301 ) for converting the narrow band LSPs of Mn order to an autocorrelation coefficients of Mn order; an inverse lag window unit ( 302 ) for applying a window which has an inverse characteristic of a lag window supposed to be applied to the autocorrelation coefficients; an extrapolation unit ( 303 ) for extending the order of the autocorrelation coefficients to (Mn+Mi) order by extrapolating the inverse lag windowed autocorrelation coefficients; an up-sample unit ( 304 ) for performing an up-sample process in the autocorrelation domain which is equivalent to an up-sample process in a time domain for the autocorrelation coefficients of the (Mn+Mi) order so as to obtain autocorrelation coefficients of Mw order; a lag window unit ( 305 ) for applying a lag window to the autocorrelation coefficients of Mw order; and an LSP conversion unit ( 306 ) for converting the lag windowed autocorrelation coefficients into LSPs.