ref: 35b98e0f4f5d021690beb4f274e637e327063e62
dir: /src/echos.c/
/* * August 24, 1998 * Copyright (C) 1998 Juergen Mueller And Sundry Contributors * This source code is freely redistributable and may be used for * any purpose. This copyright notice must be maintained. * Juergen Mueller And Sundry Contributors are not responsible for * the consequences of using this software. */ /* * Echos effect for dsp. * * Flow diagram scheme for n delays ( 1 <= n <= MAX_ECHOS ): * * * gain-in ___ * ibuff --+--------------------------------------------------->| | * | * decay 1 | | * | +----------------------------------->| | * | | * decay 2 | + | * | | +--------------------->| | * | | | * decay n | | * | _________ | _________ | _________ +--->|___| * | | | | | | | | | | | * +-->| delay 1 |-+-| delay 2 |-+...-| delay n |--+ | * gain-out * |_________| |_________| |_________| | * +----->obuff * * Usage: * echos gain-in gain-out delay-1 decay-1 [delay-2 decay-2 ... delay-n decay-n] * * Where: * gain-in, decay-1 ... decay-n : 0.0 ... 1.0 volume * gain-out : 0.0 ... volume * delay-1 ... delay-n : > 0.0 msec * * Note: * when decay is close to 1.0, the samples can begin clipping and the output * can saturate! * * Hint: * 1 / out-gain > gain-in ( 1 + decay-1 + ... + decay-n ) * */ /* * Sound Tools reverb effect file. */ #include <stdlib.h> /* Harmless, and prototypes atof() etc. --dgc */ #include <math.h> #include "st_i.h" #define DELAY_BUFSIZ ( 50L * ST_MAXRATE ) #define MAX_ECHOS 7 /* 24 bit x ( 1 + MAX_ECHOS ) = */ /* 24 bit x 8 = 32 bit !!! */ /* Private data for SKEL file */ typedef struct echosstuff { int counter[MAX_ECHOS]; int num_delays; double *delay_buf; float in_gain, out_gain; float delay[MAX_ECHOS], decay[MAX_ECHOS]; st_ssize_t samples[MAX_ECHOS], pointer[MAX_ECHOS]; st_size_t sumsamples; } *echos_t; /* Private data for SKEL file */ /* * Process options */ int st_echos_getopts(eff_t effp, int n, char **argv) { echos_t echos = (echos_t) effp->priv; int i; echos->num_delays = 0; if ((n < 4) || (n % 2)) { st_fail("Usage: echos gain-in gain-out delay decay [ delay decay ... ]"); return (ST_EOF); } i = 0; sscanf(argv[i++], "%f", &echos->in_gain); sscanf(argv[i++], "%f", &echos->out_gain); while (i < n) { /* Linux bug and it's cleaner. */ sscanf(argv[i++], "%f", &echos->delay[echos->num_delays]); sscanf(argv[i++], "%f", &echos->decay[echos->num_delays]); echos->num_delays++; if ( echos->num_delays > MAX_ECHOS ) { st_fail("echos: to many delays, use less than %i delays", MAX_ECHOS); return (ST_EOF); } } echos->sumsamples = 0; return (ST_SUCCESS); } /* * Prepare for processing. */ int st_echos_start(eff_t effp) { echos_t echos = (echos_t) effp->priv; int i; float sum_in_volume; unsigned long j; if ( echos->in_gain < 0.0 ) { st_fail("echos: gain-in must be positive!\n"); return (ST_EOF); } if ( echos->in_gain > 1.0 ) { st_fail("echos: gain-in must be less than 1.0!\n"); return (ST_EOF); } if ( echos->out_gain < 0.0 ) { st_fail("echos: gain-in must be positive!\n"); return (ST_EOF); } for ( i = 0; i < echos->num_delays; i++ ) { echos->samples[i] = echos->delay[i] * effp->ininfo.rate / 1000.0; if ( echos->samples[i] < 1 ) { st_fail("echos: delay must be positive!\n"); return (ST_EOF); } if ( echos->samples[i] > DELAY_BUFSIZ ) { st_fail("echos: delay must be less than %g seconds!\n", DELAY_BUFSIZ / (float) effp->ininfo.rate ); return (ST_EOF); } if ( echos->decay[i] < 0.0 ) { st_fail("echos: decay must be positive!\n" ); return (ST_EOF); } if ( echos->decay[i] > 1.0 ) { st_fail("echos: decay must be less than 1.0!\n" ); return (ST_EOF); } echos->counter[i] = 0; echos->pointer[i] = echos->sumsamples; echos->sumsamples += echos->samples[i]; } if (! (echos->delay_buf = (double *) malloc(sizeof (double) * echos->sumsamples))) { st_fail("echos: Cannot malloc %d bytes!\n", sizeof(double) * echos->sumsamples); return(ST_EOF); } for ( j = 0; j < echos->sumsamples; ++j ) echos->delay_buf[j] = 0.0; /* Be nice and check the hint with warning, if... */ sum_in_volume = 1.0; for ( i = 0; i < echos->num_delays; i++ ) sum_in_volume += echos->decay[i]; if ( sum_in_volume * echos->in_gain > 1.0 / echos->out_gain ) st_warn("echos: warning >>> gain-out can cause saturation of output <<<"); return (ST_SUCCESS); } /* * Processed signed long samples from ibuf to obuf. * Return number of samples processed. */ int st_echos_flow(eff_t effp, st_sample_t *ibuf, st_sample_t *obuf, st_size_t *isamp, st_size_t *osamp) { echos_t echos = (echos_t) effp->priv; int len, done; int j; double d_in, d_out; st_sample_t out; len = ((*isamp > *osamp) ? *osamp : *isamp); for(done = 0; done < len; done++) { /* Store delays as 24-bit signed longs */ d_in = (double) *ibuf++ / 256; /* Compute output first */ d_out = d_in * echos->in_gain; for ( j = 0; j < echos->num_delays; j++ ) { d_out += echos->delay_buf[echos->counter[j] + echos->pointer[j]] * echos->decay[j]; } /* Adjust the output volume and size to 24 bit */ d_out = d_out * echos->out_gain; out = st_clip24((st_sample_t) d_out); *obuf++ = out * 256; /* Mix decay of delays and input */ for ( j = 0; j < echos->num_delays; j++ ) { if ( j == 0 ) echos->delay_buf[echos->counter[j] + echos->pointer[j]] = d_in; else echos->delay_buf[echos->counter[j] + echos->pointer[j]] = echos->delay_buf[echos->counter[j-1] + echos->pointer[j-1]] + d_in; } /* Adjust the counters */ for ( j = 0; j < echos->num_delays; j++ ) echos->counter[j] = ( echos->counter[j] + 1 ) % echos->samples[j]; } /* processed all samples */ return (ST_SUCCESS); } /* * Drain out reverb lines. */ int st_echos_drain(eff_t effp, st_sample_t *obuf, st_size_t *osamp) { echos_t echos = (echos_t) effp->priv; double d_in, d_out; st_sample_t out; int j; st_size_t done; done = 0; /* drain out delay samples */ while ( ( done < *osamp ) && ( done < echos->sumsamples ) ) { d_in = 0; d_out = 0; for ( j = 0; j < echos->num_delays; j++ ) { d_out += echos->delay_buf[echos->counter[j] + echos->pointer[j]] * echos->decay[j]; } /* Adjust the output volume and size to 24 bit */ d_out = d_out * echos->out_gain; out = st_clip24((st_sample_t) d_out); *obuf++ = out * 256; /* Mix decay of delays and input */ for ( j = 0; j < echos->num_delays; j++ ) { if ( j == 0 ) echos->delay_buf[echos->counter[j] + echos->pointer[j]] = d_in; else echos->delay_buf[echos->counter[j] + echos->pointer[j]] = echos->delay_buf[echos->counter[j-1] + echos->pointer[j-1]]; } /* Adjust the counters */ for ( j = 0; j < echos->num_delays; j++ ) echos->counter[j] = ( echos->counter[j] + 1 ) % echos->samples[j]; done++; echos->sumsamples--; }; /* samples played, it remains */ *osamp = done; return (ST_SUCCESS); } /* * Clean up echos effect. */ int st_echos_stop(eff_t effp) { echos_t echos = (echos_t) effp->priv; free((char *) echos->delay_buf); echos->delay_buf = (double *) -1; /* guaranteed core dump */ return (ST_SUCCESS); }