ref: a44503f44e9973c539df5646d258a466e6fb2a9d
dir: /src/noisered.c/
/* noisered - Noise Reduction Effect.
*
* Written by Ian Turner (vectro@vectro.org)
*
* Copyright 1999 Ian Turner
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Authors are not responsible for the consequences of using this software.
*/
#include "noisered.h"
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
typedef struct {
float *window;
float *lastwindow;
float *noisegate;
float *smoothing;
} chandata_t;
/* Holds profile information */
typedef struct {
char* profile_filename;
float threshold;
chandata_t *chandata;
size_t bufdata;
} priv_t;
static void FFT(unsigned NumSamples,
int InverseTransform,
const float *RealIn, float *ImagIn, float *RealOut, float *ImagOut)
{
unsigned i;
double * work = malloc(2 * NumSamples * sizeof(*work));
for (i = 0; i < 2 * NumSamples; i += 2) {
work[i] = RealIn[i >> 1];
work[i + 1] = ImagIn? ImagIn[i >> 1] : 0;
}
lsx_safe_cdft(2 * (int)NumSamples, InverseTransform? -1 : 1, work);
if (InverseTransform) for (i = 0; i < 2 * NumSamples; i += 2) {
RealOut[i >> 1] = work[i] / NumSamples;
ImagOut[i >> 1] = work[i + 1] / NumSamples;
}
else for (i = 0; i < 2 * NumSamples; i += 2) {
RealOut[i >> 1] = work[i];
ImagOut[i >> 1] = work[i + 1];
}
free(work);
}
/*
* Get the options. Default file is stdin (if the audio
* input file isn't coming from there, of course!)
*/
static int sox_noisered_getopts(sox_effect_t * effp, int argc, char **argv)
{
priv_t * p = (priv_t *) effp->priv;
--argc, ++argv;
if (argc > 0) {
p->profile_filename = argv[0];
++argv;
--argc;
}
p->threshold = 0.5;
do { /* break-able block */
NUMERIC_PARAMETER(threshold, 0, 1);
} while (0);
return argc? lsx_usage(effp) : SOX_SUCCESS;
}
/*
* Prepare processing.
* Do all initializations.
*/
static int sox_noisered_start(sox_effect_t * effp)
{
priv_t * data = (priv_t *) effp->priv;
size_t fchannels = 0;
size_t channels = effp->in_signal.channels;
size_t i;
FILE * ifp = lsx_open_input_file(effp, data->profile_filename);
if (!ifp)
return SOX_EOF;
data->chandata = lsx_calloc(channels, sizeof(*(data->chandata)));
data->bufdata = 0;
for (i = 0; i < channels; i ++) {
data->chandata[i].noisegate = lsx_calloc(FREQCOUNT, sizeof(float));
data->chandata[i].smoothing = lsx_calloc(FREQCOUNT, sizeof(float));
data->chandata[i].lastwindow = NULL;
}
while (1) {
unsigned long i1_ul;
size_t i1;
float f1;
if (2 != fscanf(ifp, " Channel %lu: %f", &i1_ul, &f1))
break;
i1 = i1_ul;
if (i1 != fchannels) {
lsx_fail("noisered: Got channel %lu, expected channel %lu.",
(unsigned long)i1, (unsigned long)fchannels);
return SOX_EOF;
}
data->chandata[fchannels].noisegate[0] = f1;
for (i = 1; i < FREQCOUNT; i ++) {
if (1 != fscanf(ifp, ", %f", &f1)) {
lsx_fail("noisered: Not enough data for channel %lu "
"(expected %d, got %lu)", (unsigned long)fchannels, FREQCOUNT, (unsigned long)i);
return SOX_EOF;
}
data->chandata[fchannels].noisegate[i] = f1;
}
fchannels ++;
}
if (fchannels != channels) {
lsx_fail("noisered: channel mismatch: %lu in input, %lu in profile.",
(unsigned long)channels, (unsigned long)fchannels);
return SOX_EOF;
}
if (ifp != stdin)
fclose(ifp);
return (SOX_SUCCESS);
}
/* Mangle a single window. Each output sample (except the first and last
* half-window) is the result of two distinct calls to this function,
* due to overlapping windows. */
static void reduce_noise(chandata_t* chan, float* window, double level)
{
float *inr, *ini, *outr, *outi, *power;
float *smoothing = chan->smoothing;
int i;
inr = lsx_calloc(WINDOWSIZE * 5, sizeof(float));
ini = inr + WINDOWSIZE;
outr = ini + WINDOWSIZE;
outi = outr + WINDOWSIZE;
power = outi + WINDOWSIZE;
for (i = 0; i < FREQCOUNT; i ++)
assert(smoothing[i] >= 0 && smoothing[i] <= 1);
memcpy(inr, window, WINDOWSIZE*sizeof(float));
FFT(WINDOWSIZE, 0, inr, NULL, outr, outi);
memcpy(inr, window, WINDOWSIZE*sizeof(float));
lsx_apply_hann_f(inr, WINDOWSIZE);
lsx_power_spectrum_f(WINDOWSIZE, inr, power);
for (i = 0; i < FREQCOUNT; i ++) {
float smooth;
float plog;
plog = log(power[i]);
if (power[i] != 0 && plog < chan->noisegate[i] + level*8.0)
smooth = 0.0;
else
smooth = 1.0;
smoothing[i] = smooth * 0.5 + smoothing[i] * 0.5;
}
/* Audacity says this code will eliminate tinkle bells.
* I have no idea what that means. */
for (i = 2; i < FREQCOUNT - 2; i ++) {
if (smoothing[i]>=0.5 &&
smoothing[i]<=0.55 &&
smoothing[i-1]<0.1 &&
smoothing[i-2]<0.1 &&
smoothing[i+1]<0.1 &&
smoothing[i+2]<0.1)
smoothing[i] = 0.0;
}
outr[0] *= smoothing[0];
outi[0] *= smoothing[0];
outr[FREQCOUNT-1] *= smoothing[FREQCOUNT-1];
outi[FREQCOUNT-1] *= smoothing[FREQCOUNT-1];
for (i = 1; i < FREQCOUNT-1; i ++) {
int j = WINDOWSIZE - i;
float smooth = smoothing[i];
outr[i] *= smooth;
outi[i] *= smooth;
outr[j] *= smooth;
outi[j] *= smooth;
}
FFT(WINDOWSIZE, 1, outr, outi, inr, ini);
lsx_apply_hann_f(inr, WINDOWSIZE);
memcpy(window, inr, WINDOWSIZE*sizeof(float));
for (i = 0; i < FREQCOUNT; i ++)
assert(smoothing[i] >= 0 && smoothing[i] <= 1);
free(inr);
}
/* Do window management once we have a complete window, including mangling
* the current window. */
static int process_window(sox_effect_t * effp, priv_t * data, unsigned chan_num, unsigned num_chans,
sox_sample_t *obuf, unsigned len) {
int j;
float* nextwindow;
int use = min(len, WINDOWSIZE)-min(len,(WINDOWSIZE/2));
chandata_t *chan = &(data->chandata[chan_num]);
int first = (chan->lastwindow == NULL);
SOX_SAMPLE_LOCALS;
if ((nextwindow = lsx_calloc(WINDOWSIZE, sizeof(float))) == NULL)
return SOX_EOF;
memcpy(nextwindow, chan->window+WINDOWSIZE/2,
sizeof(float)*(WINDOWSIZE/2));
reduce_noise(chan, chan->window, data->threshold);
if (!first) {
for (j = 0; j < use; j ++) {
float s = chan->window[j] + chan->lastwindow[WINDOWSIZE/2 + j];
obuf[chan_num + num_chans * j] =
SOX_FLOAT_32BIT_TO_SAMPLE(s, effp->clips);
}
free(chan->lastwindow);
} else {
for (j = 0; j < use; j ++) {
assert(chan->window[j] >= -1 && chan->window[j] <= 1);
obuf[chan_num + num_chans * j] =
SOX_FLOAT_32BIT_TO_SAMPLE(chan->window[j], effp->clips);
}
}
chan->lastwindow = chan->window;
chan->window = nextwindow;
return use;
}
/*
* Read in windows, and call process_window once we get a whole one.
*/
static int sox_noisered_flow(sox_effect_t * effp, const sox_sample_t *ibuf, sox_sample_t *obuf,
size_t *isamp, size_t *osamp)
{
priv_t * data = (priv_t *) effp->priv;
size_t samp = min(*isamp, *osamp);
size_t tracks = effp->in_signal.channels;
size_t track_samples = samp / tracks;
size_t ncopy = min(track_samples, WINDOWSIZE-data->bufdata);
size_t whole_window = (ncopy + data->bufdata == WINDOWSIZE);
int oldbuf = data->bufdata;
size_t i;
/* FIXME: Make this automatic for all effects */
assert(effp->in_signal.channels == effp->out_signal.channels);
if (whole_window)
data->bufdata = WINDOWSIZE/2;
else
data->bufdata += ncopy;
/* Reduce noise on every channel. */
for (i = 0; i < tracks; i ++) {
SOX_SAMPLE_LOCALS;
chandata_t* chan = &(data->chandata[i]);
size_t j;
if (chan->window == NULL)
chan->window = lsx_calloc(WINDOWSIZE, sizeof(float));
for (j = 0; j < ncopy; j ++)
chan->window[oldbuf + j] =
SOX_SAMPLE_TO_FLOAT_32BIT(ibuf[i + tracks * j], effp->clips);
if (!whole_window)
continue;
else
process_window(effp, data, (unsigned) i, (unsigned) tracks, obuf, (unsigned) (oldbuf + ncopy));
}
*isamp = tracks*ncopy;
if (whole_window)
*osamp = tracks*(WINDOWSIZE/2);
else
*osamp = 0;
return SOX_SUCCESS;
}
/*
* We have up to half a window left to dump.
*/
static int sox_noisered_drain(sox_effect_t * effp, sox_sample_t *obuf, size_t *osamp)
{
priv_t * data = (priv_t *)effp->priv;
unsigned i;
unsigned tracks = effp->in_signal.channels;
for (i = 0; i < tracks; i ++)
*osamp = process_window(effp, data, i, tracks, obuf, (unsigned) data->bufdata);
/* FIXME: This is very picky. osamp needs to be big enough to get all
* remaining data or it will be discarded.
*/
return (SOX_EOF);
}
/*
* Clean up.
*/
static int sox_noisered_stop(sox_effect_t * effp)
{
priv_t * data = (priv_t *) effp->priv;
size_t i;
for (i = 0; i < effp->in_signal.channels; i ++) {
chandata_t* chan = &(data->chandata[i]);
free(chan->lastwindow);
free(chan->window);
free(chan->smoothing);
free(chan->noisegate);
}
free(data->chandata);
return (SOX_SUCCESS);
}
static sox_effect_handler_t sox_noisered_effect = {
"noisered",
"[profile-file [amount]]",
SOX_EFF_MCHAN|SOX_EFF_LENGTH,
sox_noisered_getopts,
sox_noisered_start,
sox_noisered_flow,
sox_noisered_drain,
sox_noisered_stop,
NULL, sizeof(priv_t)
};
const sox_effect_handler_t *lsx_noisered_effect_fn(void)
{
return &sox_noisered_effect;
}