/*- * Copyright (c) 2005 Boris Mikhaylov * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include "config.h" #include #include #include #include "alnumbers.h" #include "bs2b.h" /* Set up all data. */ static void init(struct bs2b *bs2b) { 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 = 360.0f; Fc_hi = 501.0f; G_lo = 0.398107170553497f; G_hi = 0.205671765275719f; break; case BS2B_MIDDLE_CLEVEL: /* Middle crossfeed level */ 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 = 700.0f; Fc_hi = 1021.0f; G_lo = 0.530884444230988f; G_hi = 0.250105790667544f; break; case BS2B_LOW_ECLEVEL: /* Low easy crossfeed level */ Fc_lo = 360.0f; Fc_hi = 494.0f; G_lo = 0.316227766016838f; G_hi = 0.168236228897329f; break; case BS2B_MIDDLE_ECLEVEL: /* Middle easy crossfeed level */ Fc_lo = 500.0f; 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 = 700.0f; 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 = std::exp(-al::numbers::pi_v*2.0f*Fc_lo/static_cast(bs2b->srate)); bs2b->b1_lo = x; bs2b->a0_lo = G_lo * (1.0f - x) * g; x = std::exp(-al::numbers::pi_v*2.0f*Fc_hi/static_cast(bs2b->srate)); bs2b->b1_hi = x; 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_params(struct bs2b *bs2b, int level, int srate) { if(srate <= 0) srate = 1; bs2b->level = level; bs2b->srate = srate; init(bs2b); } /* bs2b_set_params */ int bs2b_get_level(struct bs2b *bs2b) { return bs2b->level; } /* bs2b_get_level */ int bs2b_get_srate(struct bs2b *bs2b) { return bs2b->srate; } /* bs2b_get_srate */ void bs2b_clear(struct bs2b *bs2b) { std::fill(std::begin(bs2b->history), std::end(bs2b->history), bs2b::t_last_sample{}); } /* bs2b_clear */ void bs2b_cross_feed(struct bs2b *bs2b, float *Left, float *Right, size_t SamplesToDo) { const float a0_lo{bs2b->a0_lo}; const float b1_lo{bs2b->b1_lo}; const float a0_hi{bs2b->a0_hi}; const float a1_hi{bs2b->a1_hi}; const float b1_hi{bs2b->b1_hi}; float lsamples[128][2]; float rsamples[128][2]; for(size_t base{0};base < SamplesToDo;) { const size_t todo{std::min(128, SamplesToDo-base)}; /* Process left input */ float z_lo{bs2b->history[0].lo}; float z_hi{bs2b->history[0].hi}; for(size_t i{0};i < todo;i++) { lsamples[i][0] = a0_lo*Left[i] + z_lo; z_lo = b1_lo*lsamples[i][0]; lsamples[i][1] = a0_hi*Left[i] + z_hi; z_hi = a1_hi*Left[i] + b1_hi*lsamples[i][1]; } bs2b->history[0].lo = z_lo; bs2b->history[0].hi = z_hi; /* Process right input */ z_lo = bs2b->history[1].lo; z_hi = bs2b->history[1].hi; for(size_t i{0};i < todo;i++) { rsamples[i][0] = a0_lo*Right[i] + z_lo; z_lo = b1_lo*rsamples[i][0]; rsamples[i][1] = a0_hi*Right[i] + z_hi; z_hi = a1_hi*Right[i] + b1_hi*rsamples[i][1]; } bs2b->history[1].lo = z_lo; bs2b->history[1].hi = z_hi; /* Crossfeed */ for(size_t i{0};i < todo;i++) *(Left++) = lsamples[i][1] + rsamples[i][0]; for(size_t i{0};i < todo;i++) *(Right++) = rsamples[i][1] + lsamples[i][0]; base += todo; } } /* bs2b_cross_feed */