diff options
Diffstat (limited to 'Alc/bs2b.c')
| -rw-r--r-- | Alc/bs2b.c | 137 |
1 files changed, 42 insertions, 95 deletions
@@ -27,120 +27,98 @@ #include <string.h> #include "bs2b.h" +#include "alu.h" -#ifndef M_PI -#define M_PI 3.14159265358979323846 -#endif - -/* Single pole IIR filter. - * O[n] = a0*I[n] + a1*I[n-1] + b1*O[n-1] - */ - -/* Lowpass filter */ -#define lo_filter(in, out_1) (bs2b->a0_lo*(in) + bs2b->b1_lo*(out_1)) - -/* Highboost filter */ -#define hi_filter(in, in_1, out_1) (bs2b->a0_hi*(in) + bs2b->a1_hi*(in_1) + bs2b->b1_hi*(out_1)) /* Set up all data. */ static void init(struct bs2b *bs2b) { - double Fc_lo, Fc_hi; - double G_lo, G_hi; - double x; - - if ((bs2b->srate > 192000) || (bs2b->srate < 2000)) - bs2b->srate = BS2B_DEFAULT_SRATE; + float Fc_lo, Fc_hi; + float G_lo, G_hi; + float x, g; switch(bs2b->level) { case BS2B_LOW_CLEVEL: /* Low crossfeed level */ - Fc_lo = 360.0; - Fc_hi = 501.0; - G_lo = 0.398107170553497; - G_hi = 0.205671765275719; + Fc_lo = 360.0f; + Fc_hi = 501.0f; + G_lo = 0.398107170553497f; + G_hi = 0.205671765275719f; break; case BS2B_MIDDLE_CLEVEL: /* Middle crossfeed level */ - Fc_lo = 500.0; - Fc_hi = 711.0; - G_lo = 0.459726988530872; - G_hi = 0.228208484414988; + Fc_lo = 500.0f; + Fc_hi = 711.0f; + G_lo = 0.459726988530872f; + G_hi = 0.228208484414988f; break; case BS2B_HIGH_CLEVEL: /* High crossfeed level (virtual speakers are closer to itself) */ - Fc_lo = 700.0; - Fc_hi = 1021.0; - G_lo = 0.530884444230988; - G_hi = 0.250105790667544; + Fc_lo = 700.0f; + Fc_hi = 1021.0f; + G_lo = 0.530884444230988f; + G_hi = 0.250105790667544f; break; case BS2B_LOW_ECLEVEL: /* Low easy crossfeed level */ - Fc_lo = 360.0; - Fc_hi = 494.0; - G_lo = 0.316227766016838; - G_hi = 0.168236228897329; + Fc_lo = 360.0f; + Fc_hi = 494.0f; + G_lo = 0.316227766016838f; + G_hi = 0.168236228897329f; break; case BS2B_MIDDLE_ECLEVEL: /* Middle easy crossfeed level */ - Fc_lo = 500.0; - Fc_hi = 689.0; - G_lo = 0.354813389233575; - G_hi = 0.187169483835901; + Fc_lo = 500.0f; + Fc_hi = 689.0f; + G_lo = 0.354813389233575f; + G_hi = 0.187169483835901f; break; default: /* High easy crossfeed level */ bs2b->level = BS2B_HIGH_ECLEVEL; - Fc_lo = 700.0; - Fc_hi = 975.0; - G_lo = 0.398107170553497; - G_hi = 0.205671765275719; + Fc_lo = 700.0f; + Fc_hi = 975.0f; + G_lo = 0.398107170553497f; + G_hi = 0.205671765275719f; break; } /* switch */ + g = 1.0f / (1.0f - G_hi + G_lo); + /* $fc = $Fc / $s; * $d = 1 / 2 / pi / $fc; * $x = exp(-1 / $d); */ - - x = exp(-2.0 * M_PI * Fc_lo / bs2b->srate); + x = expf(-2.0f * F_PI * Fc_lo / bs2b->srate); bs2b->b1_lo = x; - bs2b->a0_lo = G_lo * (1.0 - x); + bs2b->a0_lo = G_lo * (1.0f - x) * g; - x = exp(-2.0 * M_PI * Fc_hi / bs2b->srate); + x = expf(-2.0f * F_PI * Fc_hi / bs2b->srate); bs2b->b1_hi = x; - bs2b->a0_hi = 1.0 - G_hi * (1.0 - x); - bs2b->a1_hi = -x; - - bs2b->gain = 1.0f / (float)(1.0 - G_hi + G_lo); + bs2b->a0_hi = (1.0f - G_hi * (1.0f - x)) * g; + bs2b->a1_hi = -x * g; } /* init */ + /* Exported functions. * See descriptions in "bs2b.h" */ -void bs2b_set_level(struct bs2b *bs2b, int level) +void bs2b_set_params(struct bs2b *bs2b, int level, int srate) { - if(level == bs2b->level) - return; + if(srate <= 0) srate = 1; + bs2b->level = level; + bs2b->srate = srate; init(bs2b); -} /* bs2b_set_level */ +} /* bs2b_set_params */ int bs2b_get_level(struct bs2b *bs2b) { return bs2b->level; } /* bs2b_get_level */ -void bs2b_set_srate(struct bs2b *bs2b, int srate) -{ - if (srate == bs2b->srate) - return; - bs2b->srate = srate; - init(bs2b); -} /* bs2b_set_srate */ - int bs2b_get_srate(struct bs2b *bs2b) { return bs2b->srate; @@ -151,35 +129,4 @@ void bs2b_clear(struct bs2b *bs2b) memset(&bs2b->last_sample, 0, sizeof(bs2b->last_sample)); } /* bs2b_clear */ -void bs2b_cross_feed(struct bs2b *bs2b, float *sample) -{ - /* Lowpass filter */ - bs2b->last_sample.lo[0] = lo_filter(sample[0], bs2b->last_sample.lo[0]); - bs2b->last_sample.lo[1] = lo_filter(sample[1], bs2b->last_sample.lo[1]); - - /* Highboost filter */ - bs2b->last_sample.hi[0] = hi_filter(sample[0], bs2b->last_sample.asis[0], bs2b->last_sample.hi[0]); - bs2b->last_sample.hi[1] = hi_filter(sample[1], bs2b->last_sample.asis[1], bs2b->last_sample.hi[1]); - bs2b->last_sample.asis[0] = sample[0]; - bs2b->last_sample.asis[1] = sample[1]; - - /* Crossfeed */ - sample[0] = (float)(bs2b->last_sample.hi[0] + bs2b->last_sample.lo[1]); - sample[1] = (float)(bs2b->last_sample.hi[1] + bs2b->last_sample.lo[0]); - - /* Bass boost cause allpass attenuation */ - sample[0] *= bs2b->gain; - sample[1] *= bs2b->gain; - - /* Clipping of overloaded samples */ -#if 0 - if (sample[0] > 1.0) - sample[0] = 1.0; - if (sample[0] < -1.0) - sample[0] = -1.0; - if (sample[1] > 1.0) - sample[1] = 1.0; - if (sample[1] < -1.0) - sample[1] = -1.0; -#endif -} /* bs2b_cross_feed */ +extern inline void bs2b_cross_feed(struct bs2b *bs2b, float *restrict samples); |