return 0;
}
-static void multiply(double wre, double wim, int npz, double *coeffs)
+static void cmul(double re, double im, double re2, double im2, double *RE, double *IM)
{
- double nwre = -wre, nwim = -wim;
- double cre, cim;
- int i;
-
- for (i = npz; i >= 1; i--) {
- cre = coeffs[2 * i + 0];
- cim = coeffs[2 * i + 1];
-
- coeffs[2 * i + 0] = (nwre * cre - nwim * cim) + coeffs[2 * (i - 1) + 0];
- coeffs[2 * i + 1] = (nwre * cim + nwim * cre) + coeffs[2 * (i - 1) + 1];
- }
-
- cre = coeffs[0];
- cim = coeffs[1];
- coeffs[0] = nwre * cre - nwim * cim;
- coeffs[1] = nwre * cim + nwim * cre;
+ *RE = re * re2 - im * im2;
+ *IM = re * im2 + re2 * im;
}
-static int expand(AVFilterContext *ctx, double *pz, int nb, double *coeffs)
+static int expand(AVFilterContext *ctx, double *pz, int n, double *coefs)
{
- int i;
+ coefs[2 * n] = 1.0;
- coeffs[0] = 1.0;
- coeffs[1] = 0.0;
+ for (int i = 1; i <= n; i++) {
+ for (int j = n - i; j < n; j++) {
+ double re, im;
- for (i = 0; i < nb; i++) {
- coeffs[2 * (i + 1) ] = 0.0;
- coeffs[2 * (i + 1) + 1] = 0.0;
- }
+ cmul(coefs[2 * (j + 1)], coefs[2 * (j + 1) + 1],
+ pz[2 * (i - 1)], pz[2 * (i - 1) + 1], &re, &im);
- for (i = 0; i < nb; i++)
- multiply(pz[2 * i], pz[2 * i + 1], nb, coeffs);
+ coefs[2 * j] -= re;
+ coefs[2 * j + 1] -= im;
+ }
+ }
- for (i = 0; i < nb + 1; i++) {
- if (fabs(coeffs[2 * i + 1]) > FLT_EPSILON) {
- av_log(ctx, AV_LOG_ERROR, "coeff: %f of z^%d is not real; poles/zeros are not complex conjugates.\n",
- coeffs[2 * i + 1], i);
+ for (int i = 0; i < n + 1; i++) {
+ if (fabs(coefs[2 * i + 1]) > FLT_EPSILON) {
+ av_log(ctx, AV_LOG_ERROR, "coefs: %f of z^%d is not real; poles/zeros are not complex conjugates.\n",
+ coefs[2 * i + 1], i);
return AVERROR(EINVAL);
}
}