ref: ba9c7a44430bfb074f58d3e974f583a6e24f7105
dir: /src/chorus.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. */ /* * Chorus effect. * * Flow diagram scheme for n delays ( 1 <= n <= MAX_CHORUS ): * * * gain-in ___ * ibuff -----+--------------------------------------------->| | * | _________ | | * | | | * decay 1 | | * +---->| delay 1 |----------------------------->| | * | |_________| | | * | /|\ | | * : | | | * : +-----------------+ +--------------+ | + | * : | Delay control 1 |<--| mod. speed 1 | | | * : +-----------------+ +--------------+ | | * | _________ | | * | | | * decay n | | * +---->| delay n |----------------------------->| | * |_________| | | * /|\ |___| * | | * +-----------------+ +--------------+ | * gain-out * | Delay control n |<--| mod. speed n | | * +-----------------+ +--------------+ +----->obuff * * * The delay i is controled by a sine or triangle modulation i ( 1 <= i <= n). * * Usage: * chorus gain-in gain-out delay-1 decay-1 speed-1 depth-1 -s1|t1 [ * delay-2 decay-2 speed-2 depth-2 -s2|-t2 ... ] * * Where: * gain-in, decay-1 ... decay-n : 0.0 ... 1.0 volume * gain-out : 0.0 ... volume * delay-1 ... delay-n : 20.0 ... 100.0 msec * speed-1 ... speed-n : 0.1 ... 5.0 Hz modulation 1 ... n * depth-1 ... depth-n : 0.0 ... 10.0 msec modulated delay 1 ... n * -s1 ... -sn : modulation by sine 1 ... n * -t1 ... -tn : modulation by triangle 1 ... n * * 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 chorus effect file. */ #include <stdlib.h> /* Harmless, and prototypes atof() etc. --dgc */ #include <math.h> #include <string.h> #include "st_i.h" #define MOD_SINE 0 #define MOD_TRIANGLE 1 #define MAX_CHORUS 7 /* Private data for SKEL file */ typedef struct chorusstuff { int num_chorus; int modulation[MAX_CHORUS]; int counter; long phase[MAX_CHORUS]; float *chorusbuf; float in_gain, out_gain; float delay[MAX_CHORUS], decay[MAX_CHORUS]; float speed[MAX_CHORUS], depth[MAX_CHORUS]; long length[MAX_CHORUS]; int *lookup_tab[MAX_CHORUS]; int depth_samples[MAX_CHORUS], samples[MAX_CHORUS]; int maxsamples, fade_out; } *chorus_t; /* * Process options */ int st_chorus_getopts(eff_t effp, int n, char **argv) { chorus_t chorus = (chorus_t) effp->priv; int i; chorus->num_chorus = 0; i = 0; if ( ( n < 7 ) || (( n - 2 ) % 5 ) ) { st_fail("Usage: chorus gain-in gain-out delay decay speed depth [ -s | -t ]"); return (ST_EOF); } sscanf(argv[i++], "%f", &chorus->in_gain); sscanf(argv[i++], "%f", &chorus->out_gain); while ( i < n ) { if ( chorus->num_chorus > MAX_CHORUS ) { st_fail("chorus: to many delays, use less than %i delays", MAX_CHORUS); return (ST_EOF); } sscanf(argv[i++], "%f", &chorus->delay[chorus->num_chorus]); sscanf(argv[i++], "%f", &chorus->decay[chorus->num_chorus]); sscanf(argv[i++], "%f", &chorus->speed[chorus->num_chorus]); sscanf(argv[i++], "%f", &chorus->depth[chorus->num_chorus]); if ( !strcmp(argv[i], "-s")) chorus->modulation[chorus->num_chorus] = MOD_SINE; else if ( ! strcmp(argv[i], "-t")) chorus->modulation[chorus->num_chorus] = MOD_TRIANGLE; else { st_fail("Usage: chorus gain-in gain-out delay decay speed [ -s | -t ]"); return (ST_EOF); } i++; chorus->num_chorus++; } return (ST_SUCCESS); } /* * Prepare for processing. */ int st_chorus_start(eff_t effp) { chorus_t chorus = (chorus_t) effp->priv; int i; float sum_in_volume; chorus->maxsamples = 0; if ( chorus->in_gain < 0.0 ) { st_fail("chorus: gain-in must be positive!\n"); return (ST_EOF); } if ( chorus->in_gain > 1.0 ) { st_fail("chorus: gain-in must be less than 1.0!\n"); return (ST_EOF); } if ( chorus->out_gain < 0.0 ) { st_fail("chorus: gain-out must be positive!\n"); return (ST_EOF); } for ( i = 0; i < chorus->num_chorus; i++ ) { chorus->samples[i] = (int) ( ( chorus->delay[i] + chorus->depth[i] ) * effp->ininfo.rate / 1000.0); chorus->depth_samples[i] = (int) (chorus->depth[i] * effp->ininfo.rate / 1000.0); if ( chorus->delay[i] < 20.0 ) { st_fail("chorus: delay must be more than 20.0 msec!\n"); return (ST_EOF); } if ( chorus->delay[i] > 100.0 ) { st_fail("chorus: delay must be less than 100.0 msec!\n"); return (ST_EOF); } if ( chorus->speed[i] < 0.1 ) { st_fail("chorus: speed must be more than 0.1 Hz!\n"); return (ST_EOF); } if ( chorus->speed[i] > 5.0 ) { st_fail("chorus: speed must be less than 5.0 Hz!\n"); return (ST_EOF); } if ( chorus->depth[i] < 0.0 ) { st_fail("chorus: delay must be more positive!\n"); return (ST_EOF); } if ( chorus->depth[i] > 10.0 ) { st_fail("chorus: delay must be less than 10.0 msec!\n"); return (ST_EOF); } if ( chorus->decay[i] < 0.0 ) { st_fail("chorus: decay must be positive!\n" ); return (ST_EOF); } if ( chorus->decay[i] > 1.0 ) { st_fail("chorus: decay must be less that 1.0!\n" ); return (ST_EOF); } chorus->length[i] = effp->ininfo.rate / chorus->speed[i]; if (! (chorus->lookup_tab[i] = (int *) malloc(sizeof (int) * chorus->length[i]))) { st_fail("chorus: Cannot malloc %d bytes!\n", sizeof(int) * chorus->length[i]); return (ST_EOF); } if ( chorus->modulation[i] == MOD_SINE ) st_sine(chorus->lookup_tab[i], chorus->length[i], chorus->depth_samples[i] - 1, chorus->depth_samples[i]); else st_triangle(chorus->lookup_tab[i], chorus->length[i], chorus->samples[i] - 1, chorus->depth_samples[i]); chorus->phase[i] = 0; if ( chorus->samples[i] > chorus->maxsamples ) chorus->maxsamples = chorus->samples[i]; } /* Be nice and check the hint with warning, if... */ sum_in_volume = 1.0; for ( i = 0; i < chorus->num_chorus; i++ ) sum_in_volume += chorus->decay[i]; if ( chorus->in_gain * ( sum_in_volume ) > 1.0 / chorus->out_gain ) st_warn("chorus: warning >>> gain-out can cause saturation or clipping of output <<<"); if (! (chorus->chorusbuf = (float *) malloc(sizeof (float) * chorus->maxsamples))) { st_fail("chorus: Cannot malloc %d bytes!\n", sizeof(float) * chorus->maxsamples); return (ST_EOF); } for ( i = 0; i < chorus->maxsamples; i++ ) chorus->chorusbuf[i] = 0.0; chorus->counter = 0; chorus->fade_out = chorus->maxsamples; return (ST_SUCCESS); } /* * Processed signed long samples from ibuf to obuf. * Return number of samples processed. */ int st_chorus_flow(eff_t effp, st_sample_t *ibuf, st_sample_t *obuf, st_size_t *isamp, st_size_t *osamp) { chorus_t chorus = (chorus_t) effp->priv; int len, done; int i; float 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 = (float) *ibuf++ / 256; /* Compute output first */ d_out = d_in * chorus->in_gain; for ( i = 0; i < chorus->num_chorus; i++ ) d_out += chorus->chorusbuf[(chorus->maxsamples + chorus->counter - chorus->lookup_tab[i][chorus->phase[i]]) % chorus->maxsamples] * chorus->decay[i]; /* Adjust the output volume and size to 24 bit */ d_out = d_out * chorus->out_gain; out = st_clip24((st_sample_t) d_out); *obuf++ = out * 256; /* Mix decay of delay and input */ chorus->chorusbuf[chorus->counter] = d_in; chorus->counter = ( chorus->counter + 1 ) % chorus->maxsamples; for ( i = 0; i < chorus->num_chorus; i++ ) chorus->phase[i] = ( chorus->phase[i] + 1 ) % chorus->length[i]; } /* processed all samples */ return (ST_SUCCESS); } /* * Drain out reverb lines. */ int st_chorus_drain(eff_t effp, st_sample_t *obuf, st_size_t *osamp) { chorus_t chorus = (chorus_t) effp->priv; st_size_t done; int i; float d_in, d_out; st_sample_t out; done = 0; while ( ( done < *osamp ) && ( done < chorus->fade_out ) ) { d_in = 0; d_out = 0; /* Compute output first */ for ( i = 0; i < chorus->num_chorus; i++ ) d_out += chorus->chorusbuf[(chorus->maxsamples + chorus->counter - chorus->lookup_tab[i][chorus->phase[i]]) % chorus->maxsamples] * chorus->decay[i]; /* Adjust the output volume and size to 24 bit */ d_out = d_out * chorus->out_gain; out = st_clip24((st_sample_t) d_out); *obuf++ = out * 256; /* Mix decay of delay and input */ chorus->chorusbuf[chorus->counter] = d_in; chorus->counter = ( chorus->counter + 1 ) % chorus->maxsamples; for ( i = 0; i < chorus->num_chorus; i++ ) chorus->phase[i] = ( chorus->phase[i] + 1 ) % chorus->length[i]; done++; chorus->fade_out--; } /* samples played, it remains */ *osamp = done; return (ST_SUCCESS); } /* * Clean up chorus effect. */ int st_chorus_stop(eff_t effp) { chorus_t chorus = (chorus_t) effp->priv; int i; free((char *) chorus->chorusbuf); chorus->chorusbuf = (float *) -1; /* guaranteed core dump */ for ( i = 0; i < chorus->num_chorus; i++ ) { free((char *) chorus->lookup_tab[i]); chorus->lookup_tab[i] = (int *) -1; /* guaranteed core dump */ } return (ST_SUCCESS); }