ref: 2f0ef325d4588af7a70453547fa6b4d0b703818e
dir: /src/synth.c/
/*
* synth - Synthesizer Effect.
*
* Written by Carsten Borchardt Jan 2001
* Version 0.1
*
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* The authors are not responsible for
* the consequences of using this software.
*/
#include <signal.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include "st_i.h"
static st_effect_t st_synth_effect;
#define PCOUNT 5
#define SYNTH_SINE 0
#define SYNTH_SQUARE 1
#define SYNTH_SAWTOOTH 2
#define SYNTH_TRIANGLE 3
#define SYNTH_TRAPEZIUM 4
#define SYNTH_TRAPETZ SYNTH_TRAPEZIUM /* Deprecated name for trapezium */
#define SYNTH_WHITENOISE 5
#define SYNTH_NOISE SYNTH_WHITENOISE /* Just a handy alias */
#define SYNTH_PINKNOISE 6
#define SYNTH_BROWNNOISE 7
#define SYNTH_EXP 8
#define SYNTH_CREATE 0x000
#define SYNTH_MIX 0x100
#define SYNTH_AMOD 0x200
#define SYNTH_FMOD 0x400
enum_item const synth_type[] = {
ENUM_ITEM(SYNTH_,SINE )
ENUM_ITEM(SYNTH_,SQUARE )
ENUM_ITEM(SYNTH_,SAWTOOTH )
ENUM_ITEM(SYNTH_,TRIANGLE )
ENUM_ITEM(SYNTH_,TRAPEZIUM )
ENUM_ITEM(SYNTH_,TRAPETZ )
ENUM_ITEM(SYNTH_,WHITENOISE)
ENUM_ITEM(SYNTH_,NOISE )
ENUM_ITEM(SYNTH_,PINKNOISE )
ENUM_ITEM(SYNTH_,BROWNNOISE)
ENUM_ITEM(SYNTH_,EXP )
{0, 0}};
enum_item const combine_type[] = {
ENUM_ITEM(SYNTH_,CREATE)
ENUM_ITEM(SYNTH_,MIX )
ENUM_ITEM(SYNTH_,AMOD )
ENUM_ITEM(SYNTH_,FMOD )
{0, 0}};
/* do not ask me for the colored noise, i copied the
* algorithm somewhere...
*/
#define BROWNNOISE_FAC (500.0/32768.0)
#define PINKNOISE_FAC (5000.0/32768.0)
#define LOG_10_20 0.1151292546497022842009e0
#define MAXCHAN 4
/******************************************************************************
* start of pink noise generator stuff
* algorithm stolen from:
* Author: Phil Burk, http://www.softsynth.com
*/
/* Calculate pseudo-random 32 bit number based on linear congruential method. */
static unsigned long GenerateRandomNumber( void )
{
static unsigned long randSeed = 22222; /* Change this for different random sequences. */
randSeed = (randSeed * 196314165) + 907633515;
return randSeed;
}
#define PINK_MAX_RANDOM_ROWS (30)
#define PINK_RANDOM_BITS (24)
#define PINK_RANDOM_SHIFT ((sizeof(long)*8)-PINK_RANDOM_BITS)
typedef struct{
long pink_Rows[PINK_MAX_RANDOM_ROWS];
long pink_RunningSum; /* Used to optimize summing of generators. */
int pink_Index; /* Incremented each sample. */
int pink_IndexMask; /* Index wrapped by ANDing with this mask. */
float pink_Scalar; /* Used to scale within range of -1.0 to +1.0 */
} PinkNoise;
/* Setup PinkNoise structure for N rows of generators. */
static void InitializePinkNoise( PinkNoise *pink, int numRows )
{
int i;
long pmax;
pink->pink_Index = 0;
pink->pink_IndexMask = (1<<numRows) - 1;
/* Calculate maximum possible signed random value. Extra 1 for white noise always added. */
pmax = (numRows + 1) * (1<<(PINK_RANDOM_BITS-1));
pink->pink_Scalar = 1.0f / pmax;
/* Initialize rows. */
for( i=0; i<numRows; i++ ) pink->pink_Rows[i] = 0;
pink->pink_RunningSum = 0;
}
/* Generate Pink noise values between -1.0 and +1.0 */
static float GeneratePinkNoise( PinkNoise *pink )
{
long newRandom;
long sum;
float output;
/* Increment and mask index. */
pink->pink_Index = (pink->pink_Index + 1) & pink->pink_IndexMask;
/* If index is zero, don't update any random values. */
if( pink->pink_Index != 0 )
{
/* Determine how many trailing zeros in PinkIndex. */
/* This algorithm will hang if n==0 so test first. */
int numZeros = 0;
int n = pink->pink_Index;
while( (n & 1) == 0 )
{
n = n >> 1;
numZeros++;
}
/* Replace the indexed ROWS random value.
* Subtract and add back to RunningSum instead of adding all the random
* values together. Only one changes each time.
*/
pink->pink_RunningSum -= pink->pink_Rows[numZeros];
newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;
pink->pink_RunningSum += newRandom;
pink->pink_Rows[numZeros] = newRandom;
}
/* Add extra white noise value. */
newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;
sum = pink->pink_RunningSum + newRandom;
/* Scale to range of -1.0 to 0.9999. */
output = pink->pink_Scalar * sum;
return output;
}
/**************** end of pink noise stuff */
/* Private data for the synthesizer */
typedef struct synthstuff {
/* options */
char *length_str;
int type[MAXCHAN];
int mix[MAXCHAN];
double freq[MAXCHAN];
double freq2[MAXCHAN];
double par[MAXCHAN][5];
/* internal stuff */
st_sample_t max;
st_size_t samples_done;
int rate;
st_size_t length; /* length in number of samples */
double h[MAXCHAN]; /* store values necessary for creation */
PinkNoise pinkn[MAXCHAN];
} *synth_t;
/* a note is given as an int,
* 0 => 440 Hz = A
* >0 => number of half notes 'up',
* <0 => number of half notes down,
* example 12 => A of next octave, 880Hz
*
* calculated by freq = 440Hz * 2**(note/12)
*/
static double calc_note_freq(double note){
return (440.0 * pow(2.0,note/12.0));
}
/* read string 's' and convert to frequency
* 's' can be a positive number which is the frequency in Hz
* if 's' starts with a hash '%' and a following number the corresponding
* note is calculated
* return -1 on error
*/
static double StringToFreq(char *s, char **h){
double f;
if(*s=='%'){
f = strtod(s+1,h);
if ( *h == s+1 ){
/* error*/
return -1.0;
}
f=calc_note_freq(f);
}else{
f=strtod(s,h);
if(*h==s){
return -1.0;
}
}
if( f < 0.0 )
return -1.0;
return f;
}
static void parmcopy(synth_t sy, int s, int d){
int i;
sy->freq[d]=sy->freq[s];
sy->freq2[d]=sy->freq2[s];
sy->type[d]=sy->type[s];
sy->mix[d]=sy->mix[s];
for(i=0;i<PCOUNT;i++){
sy->par[d][i]=sy->par[s][i];
}
}
/*
* Process options
*
* Don't do initialization now.
* The 'info' fields are not yet filled in.
*/
static int st_synth_getopts(eff_t effp, int n, char **argv)
{
int argn;
char *hlp;
int i;
int c;
synth_t synth = (synth_t) effp->priv;
/* set default parameters */
synth->length = 0; /* use length of input file */
synth->length_str = 0;
for(c=0;c<MAXCHAN;c++){
synth->freq[c] = 440.0;
synth->freq2[c] = 440.0;
synth->type[c]=SYNTH_SINE;
synth->mix[c] = SYNTH_CREATE;
for(i=0;i<PCOUNT;i++)
synth->par[c][i]= -1.0;
synth->par[c][0]= 0.0; /* offset */
synth->par[c][1]= 0.0; /* phase */;
}
argn=0;
if ( n<0){
st_fail(st_synth_effect.usage);
return(ST_EOF);
}
if(n==0){
/* no arg, use default*/
return(ST_SUCCESS);
}
/* read length if given ( if first par starts with digit )*/
if( isdigit((int)argv[argn][0]) || argv[argn][0] == '.') {
synth->length_str = (char *)xmalloc(strlen(argv[argn])+1);
strcpy(synth->length_str,argv[argn]);
/* Do a dummy parse of to see if it will fail */
if (st_parsesamples(0, synth->length_str, &synth->length, 't') == NULL)
{
st_fail(st_synth_effect.usage);
return (ST_EOF);
}
argn++;
}
/* for one or more channel */
/* type [combine] [f1[-f2]] [p0] [p1] [p2] [p3] [p4] */
for (c = 0; c < MAXCHAN && n > argn; c++) {
enum_item const * p = find_enum_text(argv[argn], synth_type);
if (p == NULL) {
st_fail("no type given");
return ST_EOF;
}
synth->type[c] = p->value;
if (++argn == n) break;
/* maybe there is a combine-type in next arg */
p = find_enum_text(argv[argn], combine_type);
if (p != NULL) {
synth->mix[c] = p->value;
if (++argn == n) break;
}
/* read frequencies if given */
if (isdigit((int)argv[argn][0]) || argv[argn][0] == '%') {
synth->freq2[c] = synth->freq[c] = StringToFreq(argv[argn], &hlp);
if (synth->freq[c] < 0) {
st_fail("invalid freq");
return ST_EOF;
}
if (*hlp == '-') { /* freq2 given? */
char * hlp2;
synth->freq2[c] = StringToFreq(hlp + 1, &hlp2);
if (synth->freq2[c] < 0) {
st_fail("invalid freq2");
return ST_EOF;
}
if (synth->length_str == NULL) {
st_fail("length must be given when using freq2");
return ST_EOF;
}
}
if (++argn == n) break;
}
/* read rest of parameters */
for (i = 0; argn < n && isdigit((int)argv[argn][0]); ++i, ++argn) {
if (i == PCOUNT) {
st_fail("too many parameters");
return ST_EOF;
}
synth->par[c][i] = strtod(argv[argn], &hlp);
if (hlp == argv[argn]) {
st_fail("parameter error");
return ST_EOF;
}
}
if (argn == n) break;
}
/* make some intelligent parameter initialization for channels
* where no parameters were given
*
* - if only parms for one channel were given, copy to other channels
* - if parm for 2 channels were given, copy to channel 1->3, 2->4
* - if parm for 3 channels were given, copy 2->4
*/
if(c == 0 || c >= MAXCHAN){
for(c=1;c<MAXCHAN;c++)
parmcopy(synth,0,c);
}else if(c == 1){
parmcopy(synth,0,2);
parmcopy(synth,1,3);
}else if(c == 2){
parmcopy(synth,1,3);
}
return (ST_SUCCESS);
}
/*
* Prepare processing.
* Do all initializations.
*/
static int st_synth_start(eff_t effp)
{
int i;
int c;
synth_t synth = (synth_t) effp->priv;
int shift_for_max = (4 - min(effp->outinfo.size, 4)) << 3;
synth->max = (ST_SAMPLE_MAX >> shift_for_max) << shift_for_max;
if (synth->length_str)
{
if (st_parsesamples(effp->ininfo.rate, synth->length_str,
&synth->length, 't') == NULL)
{
st_fail(st_synth_effect.usage);
return(ST_EOF);
}
}
synth->samples_done=0;
synth->rate = effp->ininfo.rate;
for(i=0;i< MAXCHAN; i++){
synth->h[i]=0.0;
}
/* parameter adjustment for all channels */
for(c=0;c<MAXCHAN;c++){
/* adjust parameter 0 - 100% to 0..1 */
for(i=0;i<PCOUNT;i++){
synth->par[c][i] /= 100.0;
}
/* give parameters nice defaults for the different 'type' */
switch(synth->type[c]){
case SYNTH_SINE:
break;
case SYNTH_SQUARE:
/* p2 is pulse width */
if(synth->par[c][2] < 0.0){
synth->par[c][2] = 0.5; /* default to 50% duty cycle */
}
break;
case SYNTH_TRIANGLE:
/* p2 is position of maximum*/
if(synth->par[c][2] < 0.0){
/* default : 0 */
synth->par[c][2]=0.5;
}
break;
case SYNTH_SAWTOOTH:
/* no parameters, use TRIANGLE to create no-default-sawtooth */
break;
case SYNTH_TRAPETZ:
/* p2 is length of rising slope,
* p3 position where falling slope begins
* p4 position of end of falling slope
*/
if(synth->par[c][2] < 0.0 ){
synth->par[c][2]= 0.1;
synth->par[c][3]= 0.5;
synth->par[c][4]= 0.6;
}else if(synth->par[c][3] < 0.0){
/* try a symetric waveform
*/
if(synth->par[c][2] <= 0.5){
synth->par[c][3] = (1.0-2.0*synth->par[c][2])/2.0;
synth->par[c][4] = synth->par[c][3] + synth->par[c][2];
}else{
/* symetric is not possible, fall back to asymetrical
* triangle
*/
synth->par[c][3]=synth->par[c][2];
synth->par[c][4]=1.0;
}
}else if(synth->par[c][4] < 0.0){
/* simple falling slope to the end */
synth->par[c][4]=1.0;
}
break;
case SYNTH_PINKNOISE:
/* Initialize pink noise signals with different numbers of rows. */
InitializePinkNoise( &(synth->pinkn[c]),10+2*c);
break;
case SYNTH_EXP:
/* p2 is position of maximum*/
if (synth->par[c][2] < 0)
synth->par[c][2] = 0.5;
/* p2 is amplitude */
if (synth->par[c][3] < 0)
synth->par[c][3] = 1;
break;
default:
break;
}
st_debug("type=%i, mix=%i, length=%u, f1=%g, f2=%g",
synth->type[c], synth->mix[c],
synth->length, synth->freq[c], synth->freq2[c]);
st_debug("p0=%g, p1=%g, p2=%g, p3=%g, p4=%g",
synth->par[c][0], synth->par[c][1],
synth->par[c][2], synth->par[c][3], synth->par[c][4]);
}
st_debug("inchan=%i, rate=%i", (int)effp->ininfo.channels,synth->rate);
return (ST_SUCCESS);
}
static st_sample_t do_synth(st_sample_t iv, synth_t synth, int c){
st_sample_t ov=iv;
double r=0.0; /* -1 .. +1 */
double f;
double om;
double sd;
double move;
double t,dt ;
if(synth->length<=0){
/* there is no way to change the freq. without knowing the length
* use startfreq all the time ...
*/
f = synth->freq[c];
}else{
f = synth->freq[c] *
exp( (log(synth->freq2[c])-log(synth->freq[c]))*
synth->samples_done/synth->length );
}
om = 1.0 / f; /* periodendauer inn sec */
t = synth->samples_done / (double)synth->rate; /* zeit seit start in sec */
dt = t - synth->h[c]; /* seit seitdem letzte periode um war. */
if( dt < om){
/* wir sind noch in der periode.. */
}else{
/* schon in naechste periode */
synth->h[c]+=om;
dt=t-synth->h[c];
}
sd= dt/om; /* position in der aktuellen periode; 0<= sd < 1*/
sd = fmod(sd+synth->par[c][1],1.0); /* phase einbauen */
switch(synth->type[c]){
case SYNTH_SINE:
r = sin(2.0 * M_PI * sd);
break;
case SYNTH_SQUARE:
/* |_______ | +1
* | | |
* |_______|__________| 0
* | | |
* | |__________| -1
* | |
* 0 p2 1
*/
if(sd < synth->par[c][2]){
r = -1.0;
}else{
r = +1.0;
}
break;
case SYNTH_SAWTOOTH:
/* | __| +1
* | __/ |
* |_______/_____| 0
* | __/ |
* |_/ | -1
* | |
* 0 1
*/
r = -1.0 + 2.0 * sd;
break;
case SYNTH_TRIANGLE:
/* | _ | +1
* | / \ |
* |__/___\__| 0
* | / \ |
* |/ \| -1
* | |
* 0 p2 1
*/
if( sd < synth->par[c][2]){ /* in rising Part of period */
r = -1.0 + 2.0 * sd / synth->par[c][2];
}else{ /* falling part */
r = 1.0 - 2.0 *
(sd-synth->par[c][2])/(1-synth->par[c][2]);
}
break;
case SYNTH_TRAPETZ:
/* | ______ |+1
* | / \ |
* |__/________\___________| 0
* | / \ |
* |/ \_________|-1
* | |
* 0 p2 p3 p4 1
*/
if( sd < synth->par[c][2]){ /* in rising part of period */
r = -1.0 + 2.0 * sd / synth->par[c][2];
}else if( sd < synth->par[c][3]){ /* in constant Part of period */
r=1.0;
}else if( sd < synth->par[c][4] ){ /* falling part */
r = 1.0 - 2.0 *
(sd - synth->par[c][3])/(synth->par[c][4]-synth->par[c][3]);
}else{
r = -1.0;
}
break;
case SYNTH_EXP:
/* | | | +1
* | | | |
* | _| |_ | 0
* | __- -__ |
* |____--- ---____ | f(p3)
* | |
* 0 p2 1
*/
move=exp( - synth->par[c][3] * LOG_10_20 * 100.0 ); /* 0 .. 1 */
if ( sd < synth->par[c][2] ) {
r = move * exp(sd * log(1.0/move)/synth->par[c][2]);
}else{
r = move *
exp( (1-sd)*log(1.0/move)/
(1.0-synth->par[c][2]));
}
/* r in 0 .. 1 */
r = r * 2.0 - 1.0; /* -1 .. +1 */
break;
case SYNTH_WHITENOISE:
r= 2.0* rand()/(double)RAND_MAX - 1.0;
break;
case SYNTH_PINKNOISE:
r = GeneratePinkNoise( &(synth->pinkn[c]) );
break;
case SYNTH_BROWNNOISE:
/* no idea if this algorithm is good enough.. */
move = 2.0* rand()/(double)RAND_MAX - 1.0;
move *= BROWNNOISE_FAC;
synth->h[c] += move;
if ((synth->h[c]) > 1.0)
synth->h[c] -= 2.0*move;
if ((synth->h[c]) < -1.0)
synth->h[c] += 2.0*move;
r=synth->h[c];
break;
default:
st_warn("synth: internal error 1");
break;
}
/* add offset, but prevent clipping */
om = fabs(synth->par[c][0]);
if( om <= 1.0 ){
r *= 1.0 - om; /* reduce amp, prevent clipping */
r += om;
}
switch(synth->mix[c]){
case SYNTH_CREATE:
ov = synth->max * r;
break;
case SYNTH_MIX:
ov = iv/2 + r*synth->max/2;
break;
case SYNTH_AMOD:
ov = (st_sample_t)(0.5*(r+1.0)*(double)iv);
break;
case SYNTH_FMOD:
ov = iv * r ;
break;
default:
st_fail("synth: internel error 2");
break;
}
return ov;
}
/*
* Processed signed long samples from ibuf to obuf.
*/
static int st_synth_flow(eff_t effp, const st_sample_t *ibuf, st_sample_t *obuf,
st_size_t *isamp, st_size_t *osamp)
{
synth_t synth = (synth_t) effp->priv;
int len; /* number of input samples */
int done = 0;
int c;
int chan=effp->ininfo.channels;
int result = ST_SUCCESS;
if(chan > MAXCHAN ){
st_fail("synth: can not operate with more than %d channels",MAXCHAN);
return(ST_EOF);
}
len = ((*isamp > *osamp) ? *osamp : *isamp) / chan;
while (done < len && result == ST_SUCCESS)
{
for(c=0;c<chan;c++){
/* each channel is independent, but the algorithm is the same */
obuf[c] = do_synth(ibuf[c],synth,c);
}
ibuf+=chan;
obuf+=chan;
++done;
synth->samples_done++;
if (synth->length > 0 && synth->samples_done == synth->length)
{
result = ST_EOF;
}
}
*isamp = *osamp = done * chan;
return result;
}
static st_effect_t st_synth_effect = {
"synth",
"Usage: synth [len] {[type] [combine] [freq[-freq2]] [off] [ph] [p1] [p2] [p3]}",
ST_EFF_MCHAN,
st_synth_getopts,
st_synth_start,
st_synth_flow,
st_effect_nothing_drain,
st_effect_nothing,
st_effect_nothing
};
const st_effect_t *st_synth_effect_fn(void)
{
return &st_synth_effect;
}
/*-------------------------------------------------------------- end of file */