ref: 993ff2b888fc03b4f6be1b3e45e9e683230d92e6
dir: /src/tempo.c/
/*
* Effect: change tempo (alter duration, maintain pitch) with a WSOLA method.
* Copyright (c) 2007 robs@users.sourceforge.net
* Based on ideas from Olli Parviainen's SoundTouch Library.
*
* 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 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,
* Fifth Floor, 51 Franklin Street, Boston, MA 02111-1301, USA.
*/
#include "sox_i.h"
#include "fifo.h"
#include "xmalloc.h"
#include <math.h>
typedef struct {
/* Configuration parameters: */
size_t channels;
sox_bool quick_search; /* Whether to quick search or linear search */
double factor; /* 1 for no change, < 1 for slower, > 1 for faster. */
size_t search; /* Wide samples to search for best overlap position */
size_t segment; /* Processing segment length in wide samples */
size_t overlap; /* In wide samples */
size_t process_size; /* # input wide samples needed to process 1 segment */
/* Buffers: */
fifo_t input_fifo;
float * overlap_buf;
fifo_t output_fifo;
/* Counters: */
size_t samples_in;
size_t samples_out;
size_t segments_total;
size_t skip_total;
} tempo_t;
/* For the Waveform Similarity part of WSOLA */
static float difference(const float * a, const float * b, size_t length)
{
float diff = 0;
size_t i = 0;
#define _ diff += sqr(a[i] - b[i]), ++i; /* Loop optimisation */
do {_ _ _ _ _ _ _ _} while (i < length); /* N.B. length ≡ 0 (mod 8) */
#undef _
return diff;
}
/* Find where the two segments are most alike over the overlap period. */
static size_t tempo_best_overlap_position(tempo_t * t, float const * new_win)
{
float * f = t->overlap_buf;
size_t j, best_pos, prev_best_pos = (t->search + 1) >> 1, step = 64;
size_t i = best_pos = t->quick_search? prev_best_pos : 0;
float diff, least_diff = difference(new_win + t->channels * i, f, t->channels * t->overlap);
int k = 0;
if (t->quick_search) do { /* hierarchical search */
for (k = -1; k <= 1; k += 2) for (j = 1; j < 4 || step == 64; ++j) {
i = prev_best_pos + k * j * step;
if ((int)i < 0 || i >= t->search)
break;
diff = difference(new_win + t->channels * i, f, t->channels * t->overlap);
if (diff < least_diff)
least_diff = diff, best_pos = i;
}
prev_best_pos = best_pos;
} while (step >>= 2);
else for (i = 1; i < t->search; i++) { /* linear search */
diff = difference(new_win + t->channels * i, f, t->channels * t->overlap);
if (diff < least_diff)
least_diff = diff, best_pos = i;
}
return best_pos;
}
/* For the Over-Lap part of WSOLA */
static void tempo_overlap(
tempo_t * t, const float * in1, const float * in2, float * output)
{
size_t i, j, k = 0;
float fade_step = 1.0f / (float) t->overlap;
for (i = 0; i < t->overlap; ++i) {
float fade_in = fade_step * (float) i;
float fade_out = 1.0f - fade_in;
for (j = 0; j < t->channels; ++j, ++k)
output[k] = in1[k] * fade_out + in2[k] * fade_in;
}
}
static void tempo_process(tempo_t * t)
{
while (fifo_occupancy(&t->input_fifo) >= t->process_size) {
size_t skip, offset = 0;
/* Copy or overlap the first bit to the output */
if (!t->segments_total)
fifo_write(&t->output_fifo, t->overlap, fifo_read_ptr(&t->input_fifo));
else {
offset = tempo_best_overlap_position(t, fifo_read_ptr(&t->input_fifo));
tempo_overlap(t, t->overlap_buf,
(float *) fifo_read_ptr(&t->input_fifo) + t->channels * offset,
fifo_write(&t->output_fifo, t->overlap, NULL));
}
/* Copy the middle bit to the output */
if (t->segment > 2 * t->overlap)
fifo_write(&t->output_fifo, t->segment - 2 * t->overlap,
(float *) fifo_read_ptr(&t->input_fifo) +
t->channels * (offset + t->overlap));
/* Copy the end bit to overlap_buf ready to be mixed with
* the beginning of the next segment. */
memcpy(t->overlap_buf,
(float *) fifo_read_ptr(&t->input_fifo) +
t->channels * (offset + t->segment - t->overlap),
t->channels * t->overlap * sizeof(*(t->overlap_buf)));
/* The Advance part of WSOLA */
skip = t->factor * (++t->segments_total * (t->segment - t->overlap)) + 0.5;
skip -= (t->search + 1) >> 1; /* So search straddles nominal skip point. */
t->skip_total += skip -= t->skip_total;
fifo_read(&t->input_fifo, skip, NULL);
}
}
static float * tempo_input(tempo_t * t, float const * samples, size_t n)
{
t->samples_in += n;
return fifo_write(&t->input_fifo, n, samples);
}
static float const * tempo_output(tempo_t * t, float * samples, size_t * n)
{
t->samples_out += *n = min(*n, fifo_occupancy(&t->output_fifo));
return fifo_read(&t->output_fifo, *n, samples);
}
/* Flush samples remaining in overlap_buf & input_fifo to the output. */
static void tempo_flush(tempo_t * t)
{
size_t samples_out = t->samples_in / t->factor + .5;
size_t remaining = samples_out - t->samples_out;
float * buff = xcalloc(128 * t->channels, sizeof(*buff));
if ((int)remaining > 0) {
while (fifo_occupancy(&t->output_fifo) < remaining) {
tempo_input(t, buff, 128);
tempo_process(t);
}
fifo_trim(&t->output_fifo, remaining);
t->samples_in = 0;
}
free(buff);
}
static void tempo_setup(tempo_t * t,
double sample_rate, sox_bool quick_search, double factor,
double segment_ms, double search_ms, double overlap_ms)
{
size_t max_skip;
t->quick_search = quick_search;
t->factor = factor;
t->segment = sample_rate * segment_ms / 1000 + .5;
t->search = sample_rate * search_ms / 1000 + .5;
t->overlap = max(sample_rate * overlap_ms / 1000 + 4.5, 16);
t->overlap &= ~7; /* Make divisible by 8 for loop optimisation */
t->overlap_buf = xmalloc(t->overlap * t->channels * sizeof(*t->overlap_buf));
max_skip = ceil(factor * (t->segment - t->overlap));
t->process_size = max(max_skip + t->overlap, t->segment) + t->search;
}
static void tempo_delete(tempo_t * t)
{
free(t->overlap_buf);
fifo_delete(&t->output_fifo);
fifo_delete(&t->input_fifo);
free(t);
}
static tempo_t * tempo_create(size_t channels)
{
tempo_t * t = xcalloc(1, sizeof(*t));
t->channels = channels;
fifo_create(&t->input_fifo, t->channels * sizeof(float));
fifo_create(&t->output_fifo, t->channels * sizeof(float));
return t;
}
/*------------------------------- SoX Wrapper --------------------------------*/
typedef struct tempo {
tempo_t * tempo;
sox_bool quick_search;
double factor, segment_ms, search_ms, overlap_ms;
} priv_t;
assert_static(sizeof(struct tempo) <= SOX_MAX_EFFECT_PRIVSIZE,
/* else */ tempo_PRIVSIZE_too_big);
static int getopts(sox_effect_t * effp, int argc, char **argv)
{
priv_t * p = (priv_t *) effp->priv;
p->segment_ms = 82; /* Set non-zero defaults: */
p->search_ms = 14;
p->overlap_ms = 12;
p->quick_search = argc && !strcmp(*argv, "-q") && (--argc, ++argv, sox_true);
do { /* break-able block */
NUMERIC_PARAMETER(factor ,0.25, 4 )
NUMERIC_PARAMETER(segment_ms , 10 , 120)
NUMERIC_PARAMETER(search_ms , 0 , 30 )
NUMERIC_PARAMETER(overlap_ms , 0 , 30 )
} while (0);
return argc || !p->factor || p->overlap_ms + p->search_ms >= p->segment_ms ?
sox_usage(effp) : SOX_SUCCESS;
}
static int start(sox_effect_t * effp)
{
priv_t * p = (priv_t *) effp->priv;
if (p->factor == 1)
return SOX_EFF_NULL;
p->tempo = tempo_create(effp->ininfo.channels);
tempo_setup(p->tempo, effp->ininfo.rate, p->quick_search, p->factor,
p->segment_ms, p->search_ms, p->overlap_ms);
return SOX_SUCCESS;
}
static int flow(sox_effect_t * effp, const sox_sample_t * ibuf,
sox_sample_t * obuf, sox_size_t * isamp, sox_size_t * osamp)
{
priv_t * p = (priv_t *) effp->priv;
sox_size_t i, odone = *osamp /= effp->ininfo.channels;
float const * s = tempo_output(p->tempo, NULL, &odone);
for (i = 0; i < odone * effp->ininfo.channels; ++i)
*obuf++ = SOX_FLOAT_32BIT_TO_SAMPLE(*s++, effp->clips);
if (*isamp && odone < *osamp) {
float * t = tempo_input(p->tempo, NULL, *isamp / effp->ininfo.channels);
for (i = *isamp; i; --i)
*t++ = SOX_SAMPLE_TO_FLOAT_32BIT(*ibuf++, effp->clips);
tempo_process(p->tempo);
}
else *isamp = 0;
*osamp = odone * effp->ininfo.channels;
return SOX_SUCCESS;
}
static int drain(sox_effect_t * effp, sox_sample_t * obuf, sox_size_t * osamp)
{
static sox_size_t isamp = 0;
tempo_flush(((priv_t *)effp->priv)->tempo);
return flow(effp, 0, obuf, &isamp, osamp);
}
static int stop(sox_effect_t * effp)
{
tempo_delete(((priv_t *)effp->priv)->tempo);
return SOX_SUCCESS;
}
sox_effect_handler_t const * sox_tempo_effect_fn(void)
{
static sox_effect_handler_t handler = {
"tempo", "[-q] factor [segment-ms [search-ms [overlap-ms]]]",
SOX_EFF_MCHAN | SOX_EFF_LENGTH, getopts, start, flow, drain, stop, NULL
};
return &handler;
}