ref: 1e2e146fe7ef2b968ab1d3acadd743e031833ece
dir: /dyn.c/
#ifdef USE_DYN /* * July 5, 1991 * Copyright 1991 Lance Norskog And Sundry Contributors * This source code is freely redistributable and may be used for * any purpose. This copyright notice must be maintained. * Lance Norskog And Sundry Contributors are not responsible for * the consequences of using this software. */ /* * Sound Tools dynamic compander effect file. * * Compresses or expands dynamic range, i.e. range between * soft and loud sounds. U-law compression basically does this. * * Doesn't work. Giving up for now. */ #include <math.h> #include "st.h" /* Private data for DYN.C file */ typedef struct dyn{ int rest; /* bytes remaining in current block */ } *dyn_t; /* * Process options */ void dyn_getopts(effp, n, argv) eff_t effp; int n; char **argv; { if (n) fail("Copy effect takes no options."); } /* * Prepare processing. */ void dyn_start(effp) eff_t effp; { /* nothing to do */ /* stuff data into delaying effects here */ } /* * Processed signed long samples from ibuf to obuf. * Return number of samples processed. */ void dyn_flow(effp, ibuf, obuf, isamp, osamp) eff_t effp; LONG *ibuf, *obuf; int *isamp, *osamp; { int len, done; LONG l; double d, tmp; int sign; #define NORMIT (65536.0) len = ((*isamp > *osamp) ? *osamp : *isamp); for(done = 0; done < len; done++) { d = *ibuf++; if (d == 0.0) l = 0; else { if (d < 0.0) { d *= -1.0; sign = -1; } else sign = 1; d /= NORMIT; tmp = log10(d); tmp = pow(8.0, tmp); tmp = tmp * NORMIT; l = tmp * sign; } *obuf++ = l; } } /* * Drain out remaining samples if the effect generates any. */ void dyn_drain(effp, obuf, osamp) LONG *obuf; int *osamp; { *osamp = 0; } /* * Do anything required when you stop reading samples. * (free allocated memory, etc.) */ void dyn_stop(effp) eff_t effp; { /* nothing to do */ } #endif /* USE_DYN */