/* --------------------------------- limiter/compressor --------------------------------- for details on how it works watch out for "http://iem.kug.ac.at/~zmoelnig/pd" ...and search for "limiter" mail2me4more!n4m8ion : zmoelnig@iem.kug.ac.at */ /* this is a limiter/compressor-object the limiter is based on Falkner's thesis "Entwicklung eines digitalen Stereo-limiters mit Hilfe des Signalprozessors DSP56001" pp.14 2108:forum::für::umläute:1999 all rights reserved and no warranties... see GNU-license for details (shipped with pd) */ #define LIMIT0 0 #define LIMIT1 1 #define COMPRESS 2 #include "zexy.h" #include #ifdef NT #define fabsf fabs #pragma warning( disable : 4244 ) #pragma warning( disable : 4305 ) #endif #define LN2 .69314718056 #define SINC1 .822462987 #define SINC2 .404460777 #define SINC3 -.188874003 #define SINC4 -.143239449 #define SINC5 .087796546 #define SINC6 .06917082 #define SINC7 -.041349667 #define SINC8 -.030578954 #define SINC9 .013226276 #define BUFSIZE 128 #define XTRASAMPS 9 #define TABLESIZE 512 /* compressor table */ /* ------------------------------------------------------------------------------------ */ // first define the structs... static t_class *limiter_class; typedef struct _limctl { // variables changed by user float limit, hold_samples, change_of_amplification; } t_limctl; typedef struct _cmpctl { float treshold, ratio; // uclimit is the very same is the limiter1-limit (decalculated relative to our treshold) float uclimit, climit_inverse; // climit == compressed limit (uclimit == uncompressed limit) float limiter_limit; // start limiting (stop compressing); == tresh/limit; float treshdB, oneminusratio; } t_cmpctl; typedef struct _inbuf { float* ringbuf; int buf_position; } t_inbuf; typedef struct _limiter { t_object x_obj; int number_of_inlets, s_n; // variables changed by process float amplification; float samples_left, still_left; int mode; t_limctl *val1, *val2; t_cmpctl *cmp; // note : limit is not the same for val1 & val2 : // at val1 it is the limit of the INPUT_VALUE // at val2 it is the limit for the AMPLIFICATION (in fact it is abs_limit1/abs_limit2) t_inbuf* in; int buf_size; } t_limiter; /* ------------------------------------------------------------------------------------ */ // then do the message - thing // do the user settings // calcs static t_float calc_holdsamples(t_float htime, int buf) { // hold_time must be greater than buffer_time to make sure that any peak_sample is amplified with its own factor float min_hold = buf / sys_getsr(); return (0.001 * sys_getsr() * ((htime > min_hold)?htime:((min_hold > 50)?min_hold:50))); } static t_float calc_coa(t_float hlife) { return (exp(LN2 * 1000 / (((hlife > 0)?hlife:15) * sys_getsr()))); } static void set_uclimit(t_limiter *x) { t_cmpctl *c = x->cmp; t_float limit = x->val1->limit, limitdB = rmstodb(limit), ratio = c->ratio, tresh = c->treshold, treshdB = rmstodb(tresh); c->climit_inverse = limit / tresh; c->uclimit = tresh / dbtorms(treshdB+(limitdB - treshdB)/ratio); c->treshdB = treshdB; c->oneminusratio = 1. - ratio; } // settings static void set_treshold(t_limiter *x, float treshold) { t_cmpctl *c = x->cmp; float tresh = dbtorms (treshold); if (tresh > x->val1->limit) tresh = x->val1->limit; c->treshold = tresh; set_uclimit(x); } static void set_ratio(t_limiter *x, float ratio) { if (ratio < 0) ratio = 1; x->cmp->ratio = ratio; set_uclimit(x); } static void set_mode(t_limiter *x, float mode) { int modus = mode; switch (modus) { case LIMIT0: x->mode = LIMIT0; break; case LIMIT1: x->mode = LIMIT1; break; case COMPRESS: x->mode = COMPRESS; break; default: x->mode = LIMIT0; break; } post("mode set to %d", x->mode); } static void set_LIMIT(t_limiter *x) { set_mode(x, LIMIT0); } static void set_CRACK(t_limiter *x) { set_mode(x, LIMIT1); } static void set_COMPRESS(t_limiter *x) { set_mode(x, COMPRESS); } static void set_bufsize(t_limiter *x, float size) { // this is really unneeded...and for historical reasons only if (size < BUFSIZE) size = BUFSIZE; x->buf_size = size + XTRASAMPS; } static void set_limit(t_limiter *x, t_floatarg limit) { if (limit < 0.00001) limit = 100; x->val1->limit = dbtorms(limit); if (x->val1->limit < x->cmp->treshold) x->cmp->treshold = x->val1->limit; set_uclimit(x); } static void set_limits(t_limiter *x, t_floatarg limit1, t_floatarg limit2) { t_float lim1, lim2; if (limit1 < 0.00001) limit1 = 100; lim1 = dbtorms(limit1); lim2 = dbtorms(limit2); if (lim2 < lim1) { lim2 = 2*lim1; // this is to prevent lim2 (which should trigger the FAST regulation) x->mode = 0; // to underrun the SLOW regulation; this would cause distortion } x->val1->limit = lim1; x->val2->limit = lim1/lim2; if (lim1 < x->cmp->treshold) x->cmp->treshold = lim1; set_uclimit(x); } static void set1(t_limiter *x, t_floatarg limit, t_floatarg hold, t_floatarg release) { t_float lim = dbtorms(limit); x->val1->limit = (lim > 0)?lim:1; x->val1->hold_samples = calc_holdsamples(hold, x->buf_size); x->val1->change_of_amplification = calc_coa(release); if (lim < x->cmp->treshold) x->cmp->treshold = lim; set_uclimit(x); } static void set2(t_limiter *x, t_floatarg limit, t_floatarg hold, t_floatarg release) { t_float lim = dbtorms(limit); x->val2->limit = (lim > x->val1->limit)?(x->val1->limit/lim):.5; x->val2->hold_samples = calc_holdsamples(hold, x->buf_size); x->val2->change_of_amplification = calc_coa(release); } static void set_compressor(t_limiter *x, t_floatarg limit, t_floatarg treshold, t_floatarg ratio) { t_cmpctl *c = x->cmp; t_float lim = dbtorms(limit); t_float tresh = dbtorms(treshold); if ((limit == 0) && (treshold = 0) && (ratio = 0)) {set_mode(x, COMPRESS); return;} if (tresh > lim) tresh = lim; if (ratio < 0.) ratio = 1.; c->ratio = ratio; x->val1->limit = lim; c->treshold = tresh; set_uclimit(x); set_mode(x, COMPRESS); } static void reset(t_limiter *x) { x->amplification = 1.; } // verbose static void status(t_limiter *x) { t_limctl *v1 = x->val1; t_limctl *v2 = x->val2; t_cmpctl *c = x->cmp; t_float sr = sys_getsr() / 1000.; switch (x->mode) { case LIMIT1: post("%d-channel crack-limiter @ %fkHz\n" "\noutput-limit\t= %fdB\nhold1\t\t= %fms\nrelease1\t= %fms\ncrack-limit\t= %fdB\nhold2\t\t= %fms\nrelease2\t= %fms\n" "\namplify\t\t= %fdB\n", x->number_of_inlets, sr, rmstodb(v1->limit), (v1->hold_samples) / sr, LN2 / (log(v1->change_of_amplification) * sr), rmstodb(v1->limit / v2->limit), (v2->hold_samples) / sr, LN2 / (log(v2->change_of_amplification) * sr), x->amplification); break; case LIMIT0: post("%d-channel limiter @ %fkHz\n" "\noutput-limit\t= %fdB\nhold\t\t= %fms\nrelease\t\t= %fms\n" "\namplify\t\t= %fdB\n", x->number_of_inlets, sr, rmstodb(v1->limit), (v1->hold_samples) / sr, LN2 / (log(v1->change_of_amplification) * sr), rmstodb(x->amplification)); break; case COMPRESS: post("%d-channel compressor @ %fkHz\n" "\noutput-limit\t= %fdB\ntreshold\t= %fdB\ninput-limit\t= %f\nratio\t\t= 1:%f\n" "\nhold\t\t= %fms\nrelease\t\t= %fms\n" "\namplify\t\t= %fdB\n", x->number_of_inlets, sr, rmstodb(c->treshold * c->climit_inverse), rmstodb(c->treshold), rmstodb(c->treshold / c->uclimit), 1./c->ratio, (v1->hold_samples) / sr, LN2 / (log(v1->change_of_amplification) * sr), rmstodb(x->amplification)); } } static void helper(t_limiter *x) { post("\n\n%c %d-channel limiter-object: mode %d", HEARTSYMBOL, x->number_of_inlets, x->mode); poststring("\n'mode '\t\t\t: (0_limiter, 1_crack-limiter, 2_compressor)"); poststring("\n'LIMIT'\t\t\t\t: set to LIMITer"); poststring("\n'CRACK'\t\t\t\t: set to CRACK-limiter"); poststring("\n'COMPRESS'\t\t\t\t: set to COMPRESSor"); switch (x->mode) { case LIMIT0: poststring("\n'limit '\t\t\t: set limit (in dB)" "\n'set '\t: set limiter"); break; case LIMIT1: poststring("\n'limits '\t: set limits (in dB)" "\n'set '\t: set limiter 1" "\n'set2 '\t: set crack-limiter"); break; case COMPRESS: poststring("\n'ratio '\t\t: set compressratio (´0.5´ instead of ´1:2´)" "\n'treshold '\t\t: set treshold of the compressor" "\n'compress '\t: set compressor" "\n..........note that is the same for COMPRESSOR and LIMITER.........."); break; default: break; } poststring("\n'print'\t\t\t\t: view actual settings" "\n'help'\t\t\t\t: view this\n"); poststring("\ncreating arguments are :\n" "\"limiter~ [ [ [ [...]]]]\": may be anything\n"); endpost(); } /* ------------------------------------------------------------------------------------ */ // now do the dsp - thing // /* ------------------------------------------------------------------------------------ */ static t_int *oversampling_maxima(t_int *w) { t_limiter *x = (t_limiter *)w[1]; t_inbuf *buf = (t_inbuf *)w[2]; t_float *in = (t_float *)w[3]; t_float *out = (t_float *)w[4]; int n = x->s_n; int bufsize = x->buf_size; int i = buf->buf_position; t_float *vp = buf->ringbuf, *ep = vp + bufsize, *bp = vp + XTRASAMPS + i; i += n; while (n--) { t_float os1, os2, max; t_float last4, last3, last2, last1, sinccurrent, current, next1, next2, next3, next4; if (bp == ep) { vp[0] = bp[-9]; vp[1] = bp[-8]; vp[2] = bp[-7]; vp[3] = bp[-6]; vp[4] = bp[-5]; vp[5] = bp[-4]; vp[6] = bp[-3]; vp[7] = bp[-2]; vp[8] = bp[-1]; bp = vp + XTRASAMPS; i -= bufsize - XTRASAMPS; } os1= fabsf(SINC8 * (last4 = bp[-8]) + SINC6 * (last3 = bp[-7]) + SINC4 * (last2 = bp[-6]) + SINC2 * (last1 = bp[-5]) + (sinccurrent = SINC1 * (current = bp[-4])) + SINC3 * (next1 = bp[-3]) + SINC5 * (next2 = bp[-2]) + SINC7 * (next3 = bp[-1]) + SINC9 * (next4 = bp[0])); os2= fabsf(SINC8 * next4 + SINC4 * next3 + SINC6 * next2 + SINC2 * next1 + sinccurrent + SINC3 * last1 + SINC5 * last2 + SINC7 * last3 + SINC9 * last4); max = fabsf(current); if (max < os1) { max = os1; } if (max < os2) { max = os2; } *bp++ = *in++; if (*out++ < max) *(out-1) = max; } buf->buf_position = i; return (w+5); } static t_int *limiter_perform(t_int *w) { t_limiter *x=(t_limiter *)w[1]; int n = x->s_n; t_float *in = (t_float *)w[2]; t_float *out= (t_float *)w[3]; t_limctl *v1 = (t_limctl *)(x->val1); t_limctl *v2 = (t_limctl *)(x->val2); t_cmpctl *c = (t_cmpctl *)(x->cmp); // now let's make things a little bit faster // these must not be changed by process const t_float limit = v1->limit; const t_float holdlong = v1->hold_samples; const t_float coa_long = v1->change_of_amplification; const t_float alimit = v2->limit; const t_float holdshort = v2->hold_samples; const t_float coa_short = v2->change_of_amplification; t_float tresh = c->treshold; t_float uclimit = c->uclimit; t_float climit_inv = c->climit_inverse; t_float oneminusratio = c->oneminusratio; // these will be changed by process t_float amp = x->amplification; t_float samplesleft = x->samples_left; t_float stillleft = x->still_left; // an intern variable... t_float max_val; switch (x->mode) { case LIMIT0: while (n--) { max_val = *in; // the MAIN routine for the 1-treshold-limiter if ((max_val * amp) > limit) { amp = limit / max_val; samplesleft = holdlong; } else { if (samplesleft > 0) { samplesleft--; } else { if ((amp *= coa_long) > 1) amp = 1; } } *out++ = amp; *in++ = 0; } break; case LIMIT1: while (n--) { max_val = *in; // the main routine 2 if ((max_val * amp) > limit) { samplesleft = ((amp = (limit / max_val)) < alimit)?holdshort:holdlong; stillleft = holdlong; } else { if (samplesleft > 0) { samplesleft--; stillleft--; } else { if (amp < alimit) { if ((amp *= coa_short) > 1) amp = 1; } else { if (stillleft > 0) { samplesleft = stillleft; } else { if ((amp *= coa_long) > 1) amp = 1; } } } } *out++ = amp; *in++ = 0; } x->still_left = stillleft; break; case COMPRESS: while (n--) { max_val = *in; // the MAIN routine for the compressor (very similar to the 1-treshold-limiter) if (max_val * amp > tresh) { amp = tresh / max_val; samplesleft = holdlong; } else if (samplesleft > 0) samplesleft--; else if ((amp *= coa_long) > 1) amp = 1; if (amp < 1.) if (amp > uclimit) // amp is still UnCompressed uclimit==limitIN/tresh; *out++ = pow(amp, oneminusratio); else *out++ = amp * climit_inv; // amp must fit for limiting : amp(new) = limit/maxval; = amp(old)*limitOUT/tresh; else *out++ = 1.; *in++ = 0.; } break; default: while (n--) *out++ = *in++ = 0.; break; } // now return the goodies x->amplification = amp; x->samples_left = samplesleft; return (w+4); } #if 0 static t_int *route_through(t_int *w) { t_float *in = (t_float *)w[1]; t_float *out = (t_float *)w[2]; int n = (int)w[3]; while(n--) { *out++ = *in; *in++ = 0; } return (w+4); } #endif void limiter_dsp(t_limiter *x, t_signal **sp) { int i = 0; t_float* sig_buf = (t_float *)getbytes(sizeof(t_float) * sp[0]->s_n); x->s_n = sp[0]->s_n; if (x->amplification == 0) x->amplification = 0.0000001; if (x->val2->limit >= 1) x->mode = 0; while (i < x->number_of_inlets) { dsp_add(oversampling_maxima, 4, x, &(x->in[i]), sp[i]->s_vec, sig_buf); i++; } dsp_add(limiter_perform, 3, x, sig_buf, sp[i]->s_vec); } /* ------------------------------------------------------------------------------------ */ // finally do the creation - things void *limiter_new(t_symbol *s, int argc, t_atom *argv) { t_limiter *x = (t_limiter *)pd_new(limiter_class); int i = 0; if (argc) set_bufsize(x, atom_getfloat(argv)); else { argc = 1; set_bufsize(x, 0); } if (argc > 64) argc=64; if (argc == 0) argc=1; x->number_of_inlets = argc--; while (argc--) { inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_signal, &s_signal); } outlet_new(&x->x_obj, &s_signal); x->in = (t_inbuf*)getbytes(sizeof(t_inbuf) * x->number_of_inlets); while (i < x->number_of_inlets) { int n; t_float* buf = (float *)getbytes(sizeof(float) * x->buf_size); x->in[i].ringbuf = buf; x->in[i].buf_position = 0; for (n = 0; n < x->buf_size; n++) x->in[i].ringbuf[n] = 0.; i++; } x->val1 = (t_limctl *)getbytes(sizeof(t_limctl)); x->val2 = (t_limctl *)getbytes(sizeof(t_limctl)); x->cmp = (t_cmpctl *)getbytes(sizeof(t_cmpctl)); x->cmp->ratio = 1.; x->cmp->treshold = 1; set1(x, 100, 30, 139); set2(x, 110, 5, 14.2); x->amplification= 1; x->samples_left = x->still_left = x->mode = 0; return (x); } void limiter_free(t_limiter *x) { int i=0; freebytes(x->val1, sizeof(t_limctl)); freebytes(x->val2, sizeof(t_limctl)); freebytes(x->cmp , sizeof(t_cmpctl)); while (i < x->number_of_inlets) freebytes(x->in[i++].ringbuf, x->buf_size * sizeof(t_float)); freebytes(x->in, x->number_of_inlets * sizeof(t_inbuf)); } /* ------------------------------------------------------------------------------------ */ /* ------------------------------------------------------------------------------------ */ void z_limiter_setup(void) { limiter_class = class_new(gensym("limiter~"), (t_newmethod)limiter_new, (t_method)limiter_free, sizeof(t_limiter), 0, A_GIMME, 0); class_addmethod(limiter_class, nullfn, gensym("signal"), 0); class_addmethod(limiter_class, (t_method)limiter_dsp, gensym("dsp"), 0); class_addmethod(limiter_class, (t_method)helper, gensym("help"), 0); class_addmethod(limiter_class, (t_method)status, gensym("print"), 0); class_sethelpsymbol(limiter_class, gensym("zexy/limiter~")); class_addmethod(limiter_class, (t_method)set_mode, gensym("mode"), A_FLOAT, 0); class_addmethod(limiter_class, (t_method)set_LIMIT, gensym("LIMIT"), 0); class_addmethod(limiter_class, (t_method)set_CRACK, gensym("CRACK"), 0); class_addmethod(limiter_class, (t_method)set_COMPRESS, gensym("COMPRESS"), 0); class_addmethod(limiter_class, (t_method)set_treshold, gensym("tresh"), A_FLOAT, 0); class_addmethod(limiter_class, (t_method)set_treshold, gensym("treshold"), A_FLOAT, 0); class_addmethod(limiter_class, (t_method)set_ratio, gensym("ratio"), A_FLOAT, 0); class_addmethod(limiter_class, (t_method)set1, gensym("set"), A_FLOAT, A_FLOAT, A_FLOAT, 0); class_addmethod(limiter_class, (t_method)set2, gensym("set2"), A_FLOAT, A_FLOAT, A_FLOAT, 0); class_addmethod(limiter_class, (t_method)set_compressor,gensym("compress"), A_FLOAT, A_FLOAT, A_FLOAT, 0); class_addmethod(limiter_class, (t_method)set_limits, gensym("limits"), A_FLOAT, A_FLOAT, 0); class_addmethod(limiter_class, (t_method)set_limit, gensym("limit"), A_FLOAT, 0); class_addfloat (limiter_class, set_limit); class_addmethod(limiter_class, (t_method)reset, gensym("reset"), 0); }