ref: 9ef99d2fb06ad3b96a216d0e5e949c8b65112f93
dir: /src/biquad.c/
/* * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser * General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library. If not, write to the Free Software Foundation, * Fifth Floor, 51 Franklin Street, Boston, MA 02111-1301, USA. */ /* Biquad filter common functions (c) 2006-7 robs@users.sourceforge.net */ #include "biquad.h" #include <string.h> static char const * const width_str[] = { "band-width(Hz)", "band-width(Hz, no warp)", /* deprecated */ "band-width(octaves)", "Q", "slope", }; static char const all_width_types[] = "hboqs"; int st_biquad_getopts(eff_t effp, int n, char **argv, int min_args, int max_args, int fc_pos, int width_pos, int gain_pos, char const * allowed_width_types, filter_t filter_type) { biquad_t p = (biquad_t) effp->priv; char width_type = *allowed_width_types; char dummy; /* To check for extraneous chars. */ p->filter_type = filter_type; if (n < min_args || n > max_args || (n > fc_pos && (sscanf(argv[fc_pos], "%lf %c", &p->fc, &dummy) != 1 || p->fc <= 0)) || (n > width_pos && ((unsigned)(sscanf(argv[width_pos], "%lf%c %c", &p->width, &width_type, &dummy)-1) > 1 || p->width <= 0)) || (n > gain_pos && sscanf(argv[gain_pos], "%lf %c", &p->gain, &dummy) != 1) || !strchr(allowed_width_types, width_type) || (width_type == 's' && p->width > 1)) { st_fail(effp->h->usage); return ST_EOF; } p->width_type = strchr(all_width_types, width_type) - all_width_types; if (p->width_type >= strlen(all_width_types)) p->width_type = 0; return ST_SUCCESS; } int st_biquad_start(eff_t effp) { biquad_t p = (biquad_t) effp->priv; /* Simplify: */ p->b2 = p->b2/p->a0; p->b1 = p->b1/p->a0; p->b0 = p->b0/p->a0; p->a2 = p->a2/p->a0; p->a1 = p->a1/p->a0; if (effp->globalinfo->octave_plot_effect) { printf( "title('SoX effect: %s gain=%g frequency=%g %s=%g (rate=%u)')\n" "xlabel('Frequency (Hz)')\n" "ylabel('Amplitude Response (dB)')\n" "Fs=%u;minF=10;maxF=Fs/2;\n" "axis([minF maxF -35 25])\n" "sweepF=logspace(log10(minF),log10(maxF),200);\n" "grid on\n" "[h,w]=freqz([%g %g %g],[1 %g %g],sweepF,Fs);\n" "semilogx(w,20*log10(h),'b')\n" "pause\n" , effp->name, p->gain, p->fc, width_str[p->width_type], p->width , effp->ininfo.rate, effp->ininfo.rate , p->b0, p->b1, p->b2, p->a1, p->a2 ); return ST_EOF; } p->o2 = p->o1 = p->i2 = p-> i1 = 0; return ST_SUCCESS; } int st_biquad_flow(eff_t effp, const st_sample_t *ibuf, st_sample_t *obuf, st_size_t *isamp, st_size_t *osamp) { biquad_t p = (biquad_t) effp->priv; st_size_t len = (*isamp > *osamp)? *osamp : *isamp; *isamp = *osamp = len; while (len--) { double o0 = *ibuf*p->b0 +p->i1*p->b1 +p->i2*p->b2 -p->o1*p->a1 -p->o2*p->a2; p->i2 = p->i1, p->i1 = *ibuf++; p->o2 = p->o1, p->o1 = o0; *obuf++ = ST_ROUND_CLIP_COUNT(o0, effp->clips); } return ST_SUCCESS; }