lsp[i] = ff_cos(lsf[i] * 20861 >> 15); // divide by PI and (0,13) -> (0,14)
}
+void ff_acelp_lsf2lspd(double *lsp, const float *lsf, int lp_order)
+{
+ int i;
+
+ for(i = 0; i < lp_order; i++)
+ lsp[i] = cos(2.0 * M_PI * lsf[i]);
+}
+
/**
* \brief decodes polynomial coefficients from LSP
* \param f [out] decoded polynomial coefficients (-0x20000000 <= (3.22) <= 0x1fffffff)
void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order)
{
int i;
- int f1[lp_half_order+1]; // (3.22)
- int f2[lp_half_order+1]; // (3.22)
+ int f1[MAX_LP_HALF_ORDER+1]; // (3.22)
+ int f2[MAX_LP_HALF_ORDER+1]; // (3.22)
lsp2poly(f1, lsp , lp_half_order);
lsp2poly(f2, lsp+1, lp_half_order);
}
}
+void ff_amrwb_lsp2lpc(const double *lsp, float *lp, int lp_order)
+{
+ int lp_half_order = lp_order >> 1;
+ double buf[lp_half_order + 1];
+ double pa[lp_half_order + 1];
+ double *qa = buf + 1;
+ int i,j;
+
+ qa[-1] = 0.0;
+
+ ff_lsp2polyf(lsp , pa, lp_half_order );
+ ff_lsp2polyf(lsp + 1, qa, lp_half_order - 1);
+
+ for (i = 1, j = lp_order - 1; i < lp_half_order; i++, j--) {
+ double paf = pa[i] * (1 + lsp[lp_order - 1]);
+ double qaf = (qa[i] - qa[i-2]) * (1 - lsp[lp_order - 1]);
+ lp[i-1] = (paf + qaf) * 0.5;
+ lp[j-1] = (paf - qaf) * 0.5;
+ }
+
+ lp[lp_half_order - 1] = (1.0 + lsp[lp_order - 1]) *
+ pa[lp_half_order] * 0.5;
+
+ lp[lp_order - 1] = lsp[lp_order - 1];
+}
+
void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd, const int16_t* lsp_prev, int lp_order)
{
- int16_t lsp_1st[lp_order]; // (0.15)
+ int16_t lsp_1st[MAX_LP_ORDER]; // (0.15)
int i;
/* LSP values for first subframe (3.2.5 of G.729, Equation 24)*/