ref: a9ae4914828d1beb5b046db23f20630c22812eec
dir: /src/synth.c/
/*
* synth - Synthesizer Effect.
*
* Copyright (c) Jan 2001 Carsten Borchardt
* Copyright (c) 2001-2007 SoX contributors
*
* 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 <string.h>
#include <math.h>
#include <ctype.h>
#include "sox_i.h"
typedef enum {
synth_sine,
synth_square,
synth_sawtooth,
synth_triangle,
synth_trapezium,
synth_trapetz = synth_trapezium, /* Deprecated name for trapezium */
synth_exp,
/* Tones above, noises below */
synth_whitenoise,
synth_noise = synth_whitenoise, /* Just a handy alias */
synth_pinknoise,
synth_brownnoise
} type_t;
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_, exp)
ENUM_ITEM(synth_, whitenoise)
ENUM_ITEM(synth_, noise)
ENUM_ITEM(synth_, pinknoise)
ENUM_ITEM(synth_, brownnoise)
{0, 0}
};
typedef enum {synth_create, synth_mix, synth_amod, synth_fmod} combine_t;
enum_item const combine_type[] = {
ENUM_ITEM(synth_, create)
ENUM_ITEM(synth_, mix)
ENUM_ITEM(synth_, amod)
ENUM_ITEM(synth_, fmod)
{0, 0}
};
/******************************************************************************
* 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 to +1 */
} 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 and +1 */
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 to 0.9999. */
output = pink->pink_Scalar * sum;
return output;
}
/**************** end of pink noise stuff */
typedef struct {
/* options */
type_t type;
combine_t combine;
double freq, freq2;
double offset, phase;
double p1, p2, p3; /* Use depends on synth type */
/* internal stuff */
double cycle_start_time_s;
double brown_noise;
PinkNoise pink_noise;
} * channel_t;
/* Private data for the synthesizer */
typedef struct {
char * length_str;
channel_t getopts_channels;
sox_size_t getopts_nchannels;
sox_ssample_t max;
sox_size_t samples_done;
sox_size_t samples_to_do;
channel_t channels;
sox_size_t number_of_channels;
} * 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)
return -1;
f = calc_note_freq(f);
} else {
f = strtod(s, h);
if (*h == s)
return -1;
}
if (f < 0)
return -1;
return f;
}
static void create_channel(channel_t chan)
{
memset(chan, 0, sizeof(*chan));
chan->freq2 = chan->freq = 440;
chan->p3 = chan->p2 = chan->p1 = -1;
}
static void set_default_parameters(channel_t chan, int c)
{
switch (chan->type) {
case synth_square: /* p1 is pulse width */
if (chan->p1 < 0)
chan->p1 = 0.5; /* default to 50% duty cycle */
break;
case synth_triangle: /* p1 is position of maximum */
if (chan->p1 < 0)
chan->p1 = 0.5;
break;
case synth_trapezium:
/* p1 is length of rising slope,
* p2 position where falling slope begins
* p3 position of end of falling slope
*/
if (chan->p1 < 0) {
chan->p1 = 0.1;
chan->p2 = 0.5;
chan->p3 = 0.6;
} else if (chan->p2 < 0) { /* try a symetric waveform */
if (chan->p1 <= 0.5) {
chan->p2 = (1 - 2 * chan->p1) / 2;
chan->p3 = chan->p2 + chan->p1;
} else {
/* symetric is not possible, fall back to asymetrical triangle */
chan->p2 = chan->p1;
chan->p3 = 1;
}
} else if (chan->p3 < 0)
chan->p3 = 1; /* simple falling slope to the end */
break;
case synth_pinknoise:
/* Initialize pink noise signals with different numbers of rows. */
InitializePinkNoise(&(chan->pink_noise), 10 + 2 * c);
break;
case synth_exp:
if (chan->p1 < 0) /* p1 is position of maximum */
chan->p1 = 0.5;
if (chan->p2 < 0) /* p2 is amplitude */
chan->p2 = 1;
break;
default: break;
}
}
static int getopts(sox_effect_t * effp, int argc, char **argv)
{
synth_t synth = (synth_t) effp->priv;
int argn = 0;
/* Get duration if given (if first arg starts with digit) */
if (argc && (isdigit(argv[argn][0]) || argv[argn][0] == '.')) {
synth->length_str = xmalloc(strlen(argv[argn]) + 1);
strcpy(synth->length_str, argv[argn]);
/* Do a dummy parse of to see if it will fail */
if (sox_parsesamples(0, synth->length_str, &synth->samples_to_do, 't') == NULL)
return sox_usage(effp);
argn++;
}
while (argn < argc) { /* type [combine] [f1[-f2] [p1 [p2 [p3 [p3 [p4]]]]]] */
channel_t chan;
char * char_ptr;
enum_item const *p = find_enum_text(argv[argn], synth_type);
if (p == NULL) {
sox_fail("no type given");
return SOX_EOF;
}
synth->getopts_channels = xrealloc(synth->getopts_channels, sizeof(*synth->getopts_channels) * (synth->getopts_nchannels + 1));
chan = &synth->getopts_channels[synth->getopts_nchannels++];
create_channel(chan);
chan->type = p->value;
if (++argn == argc)
break;
/* maybe there is a combine-type in next arg */
p = find_enum_text(argv[argn], combine_type);
if (p != NULL) {
chan->combine = p->value;
if (++argn == argc)
break;
}
/* read frequencies if given */
if (isdigit((int) argv[argn][0]) || argv[argn][0] == '%') {
chan->freq2 = chan->freq = StringToFreq(argv[argn], &char_ptr);
if (chan->freq < 0) {
sox_fail("invalid freq");
return SOX_EOF;
}
if (*char_ptr == '-') { /* freq2 given? */
char *hlp2;
chan->freq2 = StringToFreq(char_ptr + 1, &hlp2);
if (chan->freq2 < 0) {
sox_fail("invalid freq2");
return SOX_EOF;
}
if (synth->length_str == NULL) {
sox_fail("duration must be given when using freq2");
return SOX_EOF;
}
}
if (++argn == argc)
break;
}
/* read rest of parameters */
#define NUMERIC_PARAMETER(p, min, max) { \
char * end_ptr; \
double d = strtod(argv[argn], &end_ptr); \
if (end_ptr == argv[argn]) \
break; \
if (d < min || d > max || *end_ptr != '\0') { \
sox_fail("parameter error"); \
return SOX_EOF; \
} \
chan->p = d / 100; /* adjust so abs(parameter) <= 1 */\
if (++argn == argc) \
break; \
}
do { /* break-able block */
NUMERIC_PARAMETER(offset,-100, 100)
NUMERIC_PARAMETER(phase , 0, 100)
NUMERIC_PARAMETER(p1, 0, 100)
NUMERIC_PARAMETER(p2, 0, 100)
NUMERIC_PARAMETER(p1, 0, 100)
} while (0);
}
/* If no channel parameters were given, create one default channel: */
if (!synth->getopts_nchannels) {
synth->getopts_channels = xmalloc(sizeof(*synth->getopts_channels));
create_channel(&synth->getopts_channels[synth->getopts_nchannels++]);
}
if (!effp->ininfo.channels)
effp->ininfo.channels = synth->getopts_nchannels;
return SOX_SUCCESS;
}
static int start(sox_effect_t * effp)
{
synth_t synth = (synth_t) effp->priv;
unsigned i;
int shift_for_max = (4 - min(effp->outinfo.size, 4)) << 3;
synth->max = (SOX_SAMPLE_MAX >> shift_for_max) << shift_for_max;
synth->samples_done = 0;
if (synth->length_str)
if (sox_parsesamples(effp->ininfo.rate, synth->length_str, &synth->samples_to_do, 't') == NULL)
return sox_usage(effp);
synth->number_of_channels = effp->ininfo.channels;
synth->channels = xcalloc(synth->number_of_channels, sizeof(*synth->channels));
for (i = 0; i < synth->number_of_channels; ++i) {
channel_t chan = &synth->channels[i];
*chan = synth->getopts_channels[i % synth->getopts_nchannels];
set_default_parameters(chan, i);
sox_debug("type=%s, combine=%s, samples_to_do=%u, f1=%g, f2=%g, "
"offset=%g, phase=%g, p1=%g, p2=%g, p3=%g",
find_enum_value(chan->type, synth_type)->text,
find_enum_value(chan->combine, combine_type)->text,
synth->samples_to_do, chan->freq, chan->freq2,
chan->offset, chan->phase, chan->p1, chan->p2, chan->p3);
}
return SOX_SUCCESS;
}
static sox_ssample_t do_synth(sox_ssample_t synth_input, synth_t synth, int c, double rate)
{
channel_t chan = &synth->channels[c];
double synth_out; /* [-1, 1] */
if (chan->type < synth_noise) { /* Need to calculate phase: */
double f; /* Current frequency; variable if sweeping */
double cycle_period_s; /* Current period in seconds */
double total_elapsed_time_s, cycle_elapsed_time_s;
double phase; /* [0, 1) */
if (synth->samples_to_do <= 0)
f = chan->freq; /* Can't sweep if synth duration is unknown */
else
f = chan->freq * exp((log(chan->freq2) - log(chan->freq)) *
synth->samples_done / synth->samples_to_do);
cycle_period_s = 1 / f;
total_elapsed_time_s = synth->samples_done / rate;
cycle_elapsed_time_s = total_elapsed_time_s - chan->cycle_start_time_s;
if (cycle_elapsed_time_s >= cycle_period_s) { /* move to next cycle */
chan->cycle_start_time_s += cycle_period_s;
cycle_elapsed_time_s = total_elapsed_time_s - chan->cycle_start_time_s;
}
phase = cycle_elapsed_time_s / cycle_period_s;
phase = fmod(phase + chan->phase, 1.0);
switch (chan->type) {
case synth_sine:
synth_out = sin(2 * M_PI * phase);
break;
case synth_square:
/* |_______ | +1
* | | |
* |_______|__________| 0
* | | |
* | |__________| -1
* | |
* 0 p1 1
*/
synth_out = -1 + 2 * (phase < chan->p1);
break;
case synth_sawtooth:
/* | __| +1
* | __/ |
* |_______/_____| 0
* | __/ |
* |_/ | -1
* | |
* 0 1
*/
synth_out = -1 + 2 * phase;
break;
case synth_triangle:
/* | . | +1
* | / \ |
* |__/___\__| 0
* | / \ |
* |/ \| -1
* | |
* 0 p1 1
*/
if (phase < chan->p1)
synth_out = -1 + 2 * phase / chan->p1; /* In rising part of period */
else
synth_out = 1 - 2 * (phase - chan->p1) / (1 - chan->p1); /* In falling part */
break;
case synth_trapezium:
/* | ______ |+1
* | / \ |
* |__/________\___________| 0
* | / \ |
* |/ \_________|-1
* | |
* 0 p1 p2 p3 1
*/
if (phase < chan->p1) /* In rising part of period */
synth_out = -1 + 2 * phase / chan->p1;
else if (phase < chan->p2) /* In high part of period */
synth_out = 1;
else if (phase < chan->p3) /* In falling part */
synth_out = 1 - 2 * (phase - chan->p2) / (chan->p3 - chan->p2);
else /* In low part of period */
synth_out = -1;
break;
case synth_exp:
/* | | | +1
* | | | |
* | _| |_ | 0
* | __- -__ |
* |____--- ---____ | f(p2)
* | |
* 0 p1 1
*/
#define LOG_10_20 0.1151292546497022842009e0
synth_out = exp(-chan->p2 * LOG_10_20 * 100); /* 0 .. 1 */
if (phase < chan->p1)
synth_out = synth_out * exp(phase * log(1 / synth_out) / chan->p1);
else
synth_out = synth_out * exp((1 - phase) * log(1 / synth_out) / (1 - chan->p1));
synth_out = synth_out * 2 - 1; /* map 0 .. 1 to -1 .. +1 */
break;
default: synth_out = 0;
}
} else switch (chan->type) {
#define RAND (2. * rand() * (1. / RAND_MAX) - 1)
case synth_whitenoise:
synth_out = RAND;
break;
case synth_pinknoise:
synth_out = GeneratePinkNoise(&(chan->pink_noise));
break;
case synth_brownnoise:
do synth_out = chan->brown_noise + RAND * (1. / 16);
while (fabs(synth_out) > 1);
chan->brown_noise = synth_out;
break;
default: synth_out = 0;
}
/* Add offset, but prevent clipping: */
synth_out = synth_out * (1 - fabs(chan->offset)) + chan->offset;
switch (chan->combine) {
case synth_create: return synth_out * synth->max;
case synth_mix : return (synth_out * synth->max + synth_input) * 0.5;
case synth_amod : return (synth_out + 1) * synth_input * 0.5;
case synth_fmod : return synth_out * synth_input;
}
return 0;
}
static int flow(sox_effect_t * effp, const sox_ssample_t * ibuf, sox_ssample_t * obuf,
sox_size_t * isamp, sox_size_t * osamp)
{
synth_t synth = (synth_t) effp->priv;
unsigned len = min(*isamp, *osamp) / effp->ininfo.channels;
unsigned c, done, result = SOX_SUCCESS;
for (done = 0; done < len && result == SOX_SUCCESS; ++done) {
for (c = 0; c < effp->ininfo.channels; c++)
*obuf++ = do_synth(*ibuf++, synth, c, effp->ininfo.rate);
if (++synth->samples_done == synth->samples_to_do)
result = SOX_EOF;
}
*isamp = *osamp = done * effp->ininfo.channels;
return result;
}
static int stop(sox_effect_t * effp)
{
synth_t synth = (synth_t) effp->priv;
free(synth->channels);
return SOX_SUCCESS;
}
static int kill(sox_effect_t * effp)
{
synth_t synth = (synth_t) effp->priv;
free(synth->getopts_channels);
free(synth->length_str);
return SOX_SUCCESS;
}
const sox_effect_handler_t *sox_synth_effect_fn(void)
{
static sox_effect_handler_t handler = {
"synth",
"[len] {type [combine] [freq[-freq2] [off [ph [p1 [p2 [p3]]]]]]}",
SOX_EFF_MCHAN | SOX_EFF_PREC, getopts, start, flow, 0, stop, kill
};
return &handler;
}