ref: 9f2d60f9cd52a1cc5ae92e02bd862c8cb4b85f13
dir: /src/reverb.c/
/* libSoX effect: stereo reverberation
* Copyright (c) 2007 robs@users.sourceforge.net
* Filter design based on freeverb by Jezar at Dreampoint.
*
* 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 "fifo.h"
#define lsx_zalloc(var, n) var = lsx_calloc(n, sizeof(*var))
#define filter_advance(p) if (--(p)->ptr < (p)->buffer) (p)->ptr += (p)->size
#define filter_delete(p) free((p)->buffer)
typedef struct {
size_t size;
float * buffer, * ptr;
float store;
} filter_t;
static float comb_process(filter_t * p, /* gcc -O2 will inline this */
float const * input, float const * feedback, float const * hf_damping)
{
float output = *p->ptr;
p->store = output + (p->store - output) * *hf_damping;
*p->ptr = *input + p->store * *feedback;
filter_advance(p);
return output;
}
static float allpass_process(filter_t * p, /* gcc -O2 will inline this */
float const * input)
{
float output = *p->ptr;
*p->ptr = *input + output * .5;
filter_advance(p);
return output - *input;
}
static const size_t /* Filter delay lengths in samples (44100Hz sample-rate) */
comb_lengths[] = {1116, 1188, 1277, 1356, 1422, 1491, 1557, 1617},
allpass_lengths[] = {225, 341, 441, 556};
#define stereo_adjust 12
typedef struct {
filter_t comb [array_length(comb_lengths)];
filter_t allpass[array_length(allpass_lengths)];
} filter_array_t;
static void filter_array_create(filter_array_t * p, double rate,
double scale, double offset)
{
size_t i;
double r = rate * (1 / 44100.); /* Compensate for actual sample-rate */
for (i = 0; i < array_length(comb_lengths); ++i, offset = -offset)
{
filter_t * pcomb = &p->comb[i];
pcomb->size = (size_t)(scale * r * (comb_lengths[i] + stereo_adjust * offset) + .5);
pcomb->ptr = lsx_zalloc(pcomb->buffer, pcomb->size);
}
for (i = 0; i < array_length(allpass_lengths); ++i, offset = -offset)
{
filter_t * pallpass = &p->allpass[i];
pallpass->size = (size_t)(r * (allpass_lengths[i] + stereo_adjust * offset) + .5);
pallpass->ptr = lsx_zalloc(pallpass->buffer, pallpass->size);
}
}
static void filter_array_process(filter_array_t * p,
size_t length, float const * input, float * output,
float const * feedback, float const * hf_damping, float const * gain)
{
while (length--) {
float out = 0, in = *input++;
size_t i = array_length(comb_lengths) - 1;
do out += comb_process(p->comb + i, &in, feedback, hf_damping);
while (i--);
i = array_length(allpass_lengths) - 1;
do out = allpass_process(p->allpass + i, &out);
while (i--);
*output++ = out * *gain;
}
}
static void filter_array_delete(filter_array_t * p)
{
size_t i;
for (i = 0; i < array_length(allpass_lengths); ++i)
filter_delete(&p->allpass[i]);
for (i = 0; i < array_length(comb_lengths); ++i)
filter_delete(&p->comb[i]);
}
typedef struct {
float feedback;
float hf_damping;
float gain;
fifo_t input_fifo;
filter_array_t chan[2];
float * out[2];
} reverb_t;
static void reverb_create(reverb_t * p, double sample_rate_Hz,
double wet_gain_dB,
double room_scale, /* % */
double reverberance, /* % */
double hf_damping, /* % */
double pre_delay_ms,
double stereo_depth,
size_t buffer_size,
float * * out)
{
size_t i, delay = pre_delay_ms / 1000 * sample_rate_Hz + .5;
double scale = room_scale / 100 * .9 + .1;
double depth = stereo_depth / 100;
double a = -1 / log(1 - /**/.3 /**/); /* Set minimum feedback */
double b = 100 / (log(1 - /**/.98/**/) * a + 1); /* Set maximum feedback */
memset(p, 0, sizeof(*p));
p->feedback = 1 - exp((reverberance - b) / (a * b));
p->hf_damping = hf_damping / 100 * .3 + .2;
p->gain = dB_to_linear(wet_gain_dB) * .015;
fifo_create(&p->input_fifo, sizeof(float));
memset(fifo_write(&p->input_fifo, delay, 0), 0, delay * sizeof(float));
for (i = 0; i <= ceil(depth); ++i) {
filter_array_create(p->chan + i, sample_rate_Hz, scale, i * depth);
out[i] = lsx_zalloc(p->out[i], buffer_size);
}
}
static void reverb_process(reverb_t * p, size_t length)
{
size_t i;
for (i = 0; i < 2 && p->out[i]; ++i)
filter_array_process(p->chan + i, length, (float *) fifo_read_ptr(&p->input_fifo), p->out[i], &p->feedback, &p->hf_damping, &p->gain);
fifo_read(&p->input_fifo, length, NULL);
}
static void reverb_delete(reverb_t * p)
{
size_t i;
for (i = 0; i < 2 && p->out[i]; ++i) {
free(p->out[i]);
filter_array_delete(p->chan + i);
}
fifo_delete(&p->input_fifo);
}
/*------------------------------- SoX Wrapper --------------------------------*/
typedef struct {
double reverberance, hf_damping, pre_delay_ms;
double stereo_depth, wet_gain_dB, room_scale;
sox_bool wet_only;
size_t ichannels, ochannels;
struct {
reverb_t reverb;
float * dry, * wet[2];
} chan[2];
} priv_t;
static int getopts(sox_effect_t * effp, int argc, char **argv)
{
priv_t * p = (priv_t *)effp->priv;
p->reverberance = p->hf_damping = 50; /* Set non-zero defaults */
p->stereo_depth = p->room_scale = 100;
--argc, ++argv;
p->wet_only = argc && (!strcmp(*argv, "-w") || !strcmp(*argv, "--wet-only"))
&& (--argc, ++argv, sox_true);
do { /* break-able block */
NUMERIC_PARAMETER(reverberance, 0, 100)
NUMERIC_PARAMETER(hf_damping, 0, 100)
NUMERIC_PARAMETER(room_scale, 0, 100)
NUMERIC_PARAMETER(stereo_depth, 0, 100)
NUMERIC_PARAMETER(pre_delay_ms, 0, 500)
NUMERIC_PARAMETER(wet_gain_dB, -10, 10)
} while (0);
return argc ? lsx_usage(effp) : SOX_SUCCESS;
}
static int start(sox_effect_t * effp)
{
priv_t * p = (priv_t *)effp->priv;
size_t i;
p->ichannels = p->ochannels = 1;
effp->out_signal.rate = effp->in_signal.rate;
if (effp->in_signal.channels > 2 && p->stereo_depth) {
lsx_warn("stereo-depth not applicable with >2 channels");
p->stereo_depth = 0;
}
if (effp->in_signal.channels == 1 && p->stereo_depth)
effp->out_signal.channels = p->ochannels = 2;
else effp->out_signal.channels = effp->in_signal.channels;
if (effp->in_signal.channels == 2 && p->stereo_depth)
p->ichannels = p->ochannels = 2;
else effp->flows = effp->in_signal.channels;
for (i = 0; i < p->ichannels; ++i) reverb_create(
&p->chan[i].reverb, effp->in_signal.rate, p->wet_gain_dB, p->room_scale,
p->reverberance, p->hf_damping, p->pre_delay_ms, p->stereo_depth,
effp->global_info->global_info->bufsiz / p->ochannels, p->chan[i].wet);
if (effp->in_signal.mult)
*effp->in_signal.mult /= !p->wet_only + 2 * dB_to_linear(max(0,p->wet_gain_dB));
return SOX_SUCCESS;
}
static int flow(sox_effect_t * effp, const sox_sample_t * ibuf,
sox_sample_t * obuf, size_t * isamp, size_t * osamp)
{
priv_t * p = (priv_t *)effp->priv;
size_t c, i, w, len = min(*isamp / p->ichannels, *osamp / p->ochannels);
SOX_SAMPLE_LOCALS;
*isamp = len * p->ichannels, *osamp = len * p->ochannels;
for (c = 0; c < p->ichannels; ++c)
p->chan[c].dry = fifo_write(&p->chan[c].reverb.input_fifo, len, 0);
for (i = 0; i < len; ++i) for (c = 0; c < p->ichannels; ++c)
p->chan[c].dry[i] = SOX_SAMPLE_TO_FLOAT_32BIT(*ibuf++, effp->clips);
for (c = 0; c < p->ichannels; ++c)
reverb_process(&p->chan[c].reverb, len);
if (p->ichannels == 2) for (i = 0; i < len; ++i) for (w = 0; w < 2; ++w) {
float out = (1 - p->wet_only) * p->chan[w].dry[i] +
.5 * (p->chan[0].wet[w][i] + p->chan[1].wet[w][i]);
*obuf++ = SOX_FLOAT_32BIT_TO_SAMPLE(out, effp->clips);
}
else for (i = 0; i < len; ++i) for (w = 0; w < p->ochannels; ++w) {
float out = (1 - p->wet_only) * p->chan[0].dry[i] + p->chan[0].wet[w][i];
*obuf++ = SOX_FLOAT_32BIT_TO_SAMPLE(out, effp->clips);
}
return SOX_SUCCESS;
}
static int stop(sox_effect_t * effp)
{
priv_t * p = (priv_t *)effp->priv;
size_t i;
for (i = 0; i < p->ichannels; ++i)
reverb_delete(&p->chan[i].reverb);
return SOX_SUCCESS;
}
sox_effect_handler_t const *lsx_reverb_effect_fn(void)
{
static sox_effect_handler_t handler = {"reverb",
"[-w|--wet-only]"
" [reverberance (50%)"
" [HF-damping (50%)"
" [room-scale (100%)"
" [stereo-depth (100%)"
" [pre-delay (0ms)"
" [wet-gain (0dB)"
"]]]]]]",
SOX_EFF_MCHAN, getopts, start, flow, NULL, stop, NULL, sizeof(priv_t)
};
return &handler;
}