ref: dc40c19c801405e04f0202fcaffe87278c0dbe30
dir: /src/vad.c/
/* libSoX effect: Voice Activity Detector (c) 2009 robs@users.sourceforge.net
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "sox_i.h"
#include "sgetopt.h"
#include <string.h>
typedef struct {
double * dft_buf, * noise_buf, * spectrum, * meas_buf, mean_meas;
} chan_t;
typedef struct { /* Configuration parameters: */
double noise_tc_up, noise_tc_down, noise_reduction_amount;
double measure_freq, measure_duration, measure_tc, pre_trigger_time;
double hp_filter_freq, lp_filter_freq, hp_lifter_freq, lp_lifter_freq;
double trigger_tc, trigger_level1, search_time, gap_time;
/* Working variables: */
sox_sample_t * buffer;
unsigned dft_len, buffer_len, buffer_ptr, flush_done, gap_count;
unsigned measure_period_len, measure_len, search_count, search_ptr;
unsigned spectrum_start, spectrum_end, cepstrum_start, cepstrum_end;
int measure_timer, booting;
double measure_tc_mult, trigger_meas_tc_mult;
double noise_tc_up_mult, noise_tc_down_mult;
double * spectrum_window, * cepstrum_window;
chan_t * channels;
} priv_t;
#define GETOPT_FREQ(c, name, min) \
case c: p->name = lsx_parse_frequency(lsx_optarg, &parse_ptr); \
if (p->name < min || *parse_ptr) return lsx_usage(effp); \
break;
static int create(sox_effect_t * effp, int argc, char * * argv)
{
priv_t * p = (priv_t *)effp->priv;
#define opt_str "+N:n:r:f:m:M:h:l:H:L:T:t:s:g:p:"
int c;
p->noise_tc_up = .1;
p->noise_tc_down = .01;
p->noise_reduction_amount = 1.35;
p->measure_freq = 20;
p->measure_duration = 2 / p->measure_freq;
p->measure_tc = .4;
p->hp_filter_freq = 50;
p->lp_filter_freq = 6000;
p->hp_lifter_freq = 150;
p->lp_lifter_freq = 2000;
p->trigger_tc = .25;
p->trigger_level1 = 7;
p->search_time = 1;
p->gap_time = .25;
while ((c = lsx_getopt(argc, argv, opt_str)) != -1) switch (c) {
char * parse_ptr;
GETOPT_NUMERIC('N', noise_tc_up , .1 , 10)
GETOPT_NUMERIC('n', noise_tc_down ,.001 , .1)
GETOPT_NUMERIC('r', noise_reduction_amount ,0 , 2)
GETOPT_NUMERIC('f', measure_freq , 5 , 50)
GETOPT_NUMERIC('m', measure_duration, .01 , 1)
GETOPT_NUMERIC('M', measure_tc , .1 , 1)
GETOPT_FREQ( 'h', hp_filter_freq , 10)
GETOPT_FREQ( 'l', lp_filter_freq , 1000)
GETOPT_FREQ( 'H', hp_lifter_freq , 10)
GETOPT_FREQ( 'L', lp_lifter_freq , 1000)
GETOPT_NUMERIC('T', trigger_tc , .01 , 1)
GETOPT_NUMERIC('t', trigger_level1 , 0 , 10)
GETOPT_NUMERIC('s', search_time , .1 , 4)
GETOPT_NUMERIC('g', gap_time , .1 , 1)
GETOPT_NUMERIC('p', pre_trigger_time, 0 , 4)
default: lsx_fail("invalid option `-%c'", optopt); return lsx_usage(effp);
}
return lsx_optind !=argc? lsx_usage(effp) : SOX_SUCCESS;
}
static int start(sox_effect_t * effp)
{
priv_t * p = (priv_t *)effp->priv;
unsigned i, pre_trigger_len, search_len;
pre_trigger_len = p->pre_trigger_time * effp->in_signal.rate + .5;
pre_trigger_len *= effp->in_signal.channels;
p->measure_len = effp->in_signal.rate * p->measure_duration + .5;
p->measure_len *= effp->in_signal.channels;
p->measure_period_len = effp->in_signal.rate / p->measure_freq + .5;
p->measure_period_len *= effp->in_signal.channels;
p->search_count = ceil(p->search_time * p->measure_freq);
search_len = p->search_count * p->measure_period_len;
p->gap_count = p->gap_time * p->measure_freq + .5;
p->buffer_len = pre_trigger_len + p->measure_len + search_len;
lsx_Calloc(p->buffer, p->buffer_len);
for (p->dft_len = 16; p->dft_len < p->measure_len; p->dft_len <<= 1);
lsx_debug("dft_len=%u measure_len=%u", p->dft_len, p->measure_len);
lsx_Calloc(p->channels, effp->in_signal.channels);
for (i = 0; i < effp->in_signal.channels; ++i) {
chan_t * c = &p->channels[i];
lsx_Calloc(c->dft_buf, p->dft_len);
lsx_Calloc(c->spectrum, p->dft_len);
lsx_Calloc(c->noise_buf, p->dft_len);
lsx_Calloc(c->meas_buf, p->search_count);
}
lsx_Calloc(p->spectrum_window, p->measure_len);
for (i = 0; i < p->measure_len; ++i)
p->spectrum_window[i] = -2. / SOX_SAMPLE_MIN / sqrt((double)p->measure_len);
lsx_apply_hann(p->spectrum_window, (int)p->measure_len);
p->spectrum_start = p->hp_filter_freq / effp->in_signal.rate * p->dft_len + .5;
p->spectrum_start = max(p->spectrum_start, 1);
p->spectrum_end = p->lp_filter_freq / effp->in_signal.rate * p->dft_len + .5;
p->spectrum_end = min(p->spectrum_end, p->dft_len / 2);
lsx_Calloc(p->cepstrum_window, p->spectrum_end - p->spectrum_start);
for (i = 0; i < p->spectrum_end - p->spectrum_start; ++i)
p->cepstrum_window[i] = 2 / sqrt((double)p->spectrum_end - p->spectrum_start);
lsx_apply_hann(p->cepstrum_window, (int)(p->spectrum_end - p->spectrum_start));
p->cepstrum_start = ceil(effp->in_signal.rate * .5 / p->lp_lifter_freq);
p->cepstrum_end = floor(effp->in_signal.rate * .5 / p->hp_lifter_freq);
p->cepstrum_end = min(p->cepstrum_end, p->dft_len / 4);
if (p->cepstrum_end <= p->cepstrum_start)
return SOX_EOF;
p->noise_tc_up_mult = exp(-1 / (p->noise_tc_up * p->measure_freq));
p->noise_tc_down_mult = exp(-1 / (p->noise_tc_down * p->measure_freq));
p->measure_tc_mult = exp(-1 / (p->measure_tc * p->measure_freq));
p->trigger_meas_tc_mult = exp(-1 / (p->trigger_tc * p->measure_freq));
p->measure_timer = -p->measure_len;
p->flush_done = p->buffer_ptr = 0;
return SOX_SUCCESS;
}
static int flow_flush(sox_effect_t * effp, sox_sample_t const * ibuf,
sox_sample_t * obuf, size_t * ilen, size_t * olen)
{
priv_t * p = (priv_t *)effp->priv;
size_t odone = min(p->buffer_len - p->flush_done, *olen);
size_t odone1 = min(odone, p->buffer_len - p->buffer_ptr);
memcpy(obuf, p->buffer + p->buffer_ptr, odone1 * sizeof(*obuf));
if ((p->buffer_ptr += odone1) == p->buffer_len) {
memcpy(obuf + odone1, p->buffer, (odone - odone1) * sizeof(*obuf));
p->buffer_ptr = odone - odone1;
}
if ((p->flush_done += odone) == p->buffer_len) {
size_t olen1 = *olen - odone;
(effp->handler.flow = lsx_flow_copy)(effp, ibuf, obuf +odone, ilen, &olen1);
odone += olen1;
}
else *ilen = 0;
*olen = odone;
return SOX_SUCCESS;
}
static double measure(
priv_t * p, chan_t * c, size_t index, unsigned step, int booting)
{
double mult, result = 0;
size_t i;
for (i = 0; i < p->measure_len; ++i, index = (index + step) % p->buffer_len)
c->dft_buf[i] = p->buffer[index] * p->spectrum_window[i];
memset(c->dft_buf + i, 0, (p->dft_len - i) * sizeof(*c->dft_buf));
lsx_safe_rdft((int)p->dft_len, 1, c->dft_buf);
memset(c->dft_buf, 0, p->spectrum_start * sizeof(*c->dft_buf));
for (i = p->spectrum_start; i < p->spectrum_end; ++i) {
double d = sqrt(sqr(c->dft_buf[2 * i]) + sqr(c->dft_buf[2 * i + 1]));
mult = booting >= 0? booting / (1. + booting) : p->measure_tc_mult;
c->spectrum[i] = c->spectrum[i] * mult + d * (1 - mult);
d = sqr(c->spectrum[i]);
mult = booting >= 0? 0 :
d > c->noise_buf[i]? p->noise_tc_up_mult : p->noise_tc_down_mult;
c->noise_buf[i] = c->noise_buf[i] * mult + d * (1 - mult);
d = sqrt(max(0, d - p->noise_reduction_amount * c->noise_buf[i]));
c->dft_buf[i] = d * p->cepstrum_window[i - p->spectrum_start];
}
memset(c->dft_buf + i, 0, ((p->dft_len >> 1) - i) * sizeof(*c->dft_buf));
lsx_safe_rdft((int)p->dft_len >> 1, 1, c->dft_buf);
for (i = p->cepstrum_start; i < p->cepstrum_end; ++i)
result += sqr(c->dft_buf[2 * i]) + sqr(c->dft_buf[2 * i + 1]);
result = log(result / (p->cepstrum_end - p->cepstrum_start));
return max(0, 21 + result);
}
static int flow_trigger(sox_effect_t * effp, sox_sample_t const * ibuf,
sox_sample_t * obuf, size_t * ilen, size_t * olen)
{
priv_t * p = (priv_t *)effp->priv;
sox_bool triggered = sox_false;
size_t i, idone = 0, to_flush = 0;
while (idone < *ilen && !triggered) {
p->measure_timer += effp->in_signal.channels;
for (i = 0; i < effp->in_signal.channels; ++i, ++idone) {
chan_t * c = &p->channels[i];
p->buffer[p->buffer_ptr++] = *ibuf++;
if (!p->measure_timer) {
size_t x = (p->buffer_ptr + p->buffer_len - p->measure_len) % p->buffer_len;
double meas = measure(p, c, x, effp->in_signal.channels, p->booting);
c->meas_buf[p->search_ptr] = meas;
c->mean_meas = c->mean_meas * p->trigger_meas_tc_mult +
meas *(1 - p->trigger_meas_tc_mult);
if (triggered |= c->mean_meas > p->trigger_level1) {
unsigned n = p->search_count, ptr = p->search_ptr;
unsigned j, trigger_j = n, zero_j = n;
for (j = 0; j < n; ++j, ptr = (ptr + n - 1) % n)
if (c->meas_buf[ptr] > p->trigger_level1 && j <= trigger_j + p->gap_count)
zero_j = trigger_j = j;
else if (!c->meas_buf[ptr] && trigger_j >= zero_j)
zero_j = j;
j = min(j, zero_j);
to_flush = range_limit(j, to_flush, n);
}
lsx_debug_more("%12g %12g %u", meas, c->mean_meas, (unsigned)to_flush);
}
}
if (p->buffer_ptr == p->buffer_len)
p->buffer_ptr = 0;
if (!p->measure_timer) {
p->measure_timer = -p->measure_period_len;
p->search_ptr = (p->search_ptr + 1) % p->search_count;
if (p->booting >= 0)
p->booting = p->booting == 6? -1 : p->booting + 1;
}
}
if (triggered) {
size_t ilen1 = *ilen - idone;
p->flush_done = (p->search_count - to_flush) * p->measure_period_len;
p->buffer_ptr = (p->buffer_ptr + p->flush_done) % p->buffer_len;
(effp->handler.flow = flow_flush)(effp, ibuf, obuf, &ilen1, olen);
idone += ilen1;
}
else *olen = 0;
*ilen = idone;
return SOX_SUCCESS;
}
static int drain(sox_effect_t * effp, sox_sample_t * obuf, size_t * olen)
{
size_t ilen = 0;
return effp->handler.flow(effp, NULL, obuf, &ilen, olen);
}
static int stop(sox_effect_t * effp)
{
priv_t * p = (priv_t *)effp->priv;
unsigned i;
for (i = 0; i < effp->in_signal.channels; ++i) {
chan_t * c = &p->channels[i];
free(c->meas_buf);
free(c->noise_buf);
free(c->spectrum);
free(c->dft_buf);
}
free(p->channels);
free(p->cepstrum_window);
free(p->spectrum_window);
free(p->buffer);
return SOX_SUCCESS;
}
sox_effect_handler_t const * lsx_vad_effect_fn(void)
{
static sox_effect_handler_t handler = {"vad", NULL,
SOX_EFF_MCHAN | SOX_EFF_LENGTH | SOX_EFF_MODIFY,
create, start, flow_trigger, drain, stop, NULL, sizeof(priv_t)
};
static char const * lines[] = {
"[options]",
"\t-N noise-tc-up (0.1 s)",
"\t-n noise-tc-down (0.01 s)",
"\t-r noise-reduction-amount (1.35)",
"\t-f measure-frequency (20 Hz)",
"\t-m measure-duration (0.1 s)",
"\t-M measure-tc (0.4 s)",
"\t-h high-pass-filter (50 Hz)",
"\t-l low-pass-filter (6000 Hz)",
"\t-H high-pass-lifter (150 Hz)",
"\t-L low-pass-lifter (2000 Hz)",
"\t-T trigger-time-constant (0.25 s)",
"\t-t trigger-level (7)",
"\t-s search-time (1 s)",
"\t-g allowed-gap (0.25 s)",
"\t-p pre-trigger-buffer (0 s)",
};
static char * usage;
handler.usage = lsx_usage_lines(&usage, lines, array_length(lines));
return &handler;
}