+ int n = 1 << nbits;
+ int i;
+ const double theta = (trans == DFT_R2C || trans == DFT_C2R ? -1 : 1)*2*M_PI/n;
+
+ s->nbits = nbits;
+ s->inverse = trans == IDFT_C2R || trans == DFT_C2R;
+ s->sign_convention = trans == IDFT_R2C || trans == DFT_C2R ? 1 : -1;
+
+ if (nbits < 4 || nbits > 16)
+ return -1;
+
+ if (ff_fft_init(&s->fft, nbits-1, trans == IDFT_C2R || trans == IDFT_R2C) < 0)
+ return -1;
+
+ ff_init_ff_cos_tabs(nbits);
+ s->tcos = ff_cos_tabs[nbits];
+ s->tsin = ff_sin_tabs[nbits]+(trans == DFT_R2C || trans == DFT_C2R)*(n>>2);
+#if !CONFIG_HARDCODED_TABLES
+ for (i = 0; i < (n>>2); i++) {
+ s->tsin[i] = sin(i*theta);
+ }
+#endif
+ s->rdft_calc = ff_rdft_calc_c;
+
+ if (ARCH_ARM) ff_rdft_init_arm(s);
+
+ return 0;