ref: 65c7a43ff357d20a375cbc0f2bbbb9184b1da10e
dir: /src/fade.c/
/* Ari Moisio <armoi@sci.fi> Aug 29 2000, based on skeleton effect
* Written by Chris Bagwell (cbagwell@sprynet.com) - March 16, 1999
*
* Copyright 1999 Chris Bagwell And Sundry Contributors
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Chris Bagwell And Sundry Contributors are not responsible for
* the consequences of using this software.
*/
#include "sox_i.h"
/* Fade curves */
#define FADE_QUARTER 'q' /* Quarter of sine wave, 0 to pi/2 */
#define FADE_HALF 'h' /* Half of sine wave, pi/2 to 1.5 * pi
* scaled so that -1 means no output
* and 1 means 0 db attenuation. */
#define FADE_LOG 'l' /* Logarithmic curve. Fades -100 db
* in given time. */
#define FADE_TRI 't' /* Linear slope. */
#define FADE_PAR 'p' /* Inverted parabola. */
#include <string.h>
/* Private data for fade file */
typedef struct { /* These are measured as samples */
uint64_t in_start, in_stop, out_start, out_stop, samplesdone;
char *in_stop_str, *out_start_str, *out_stop_str;
char in_fadetype, out_fadetype;
char do_out;
int endpadwarned;
} priv_t;
/* prototypes */
static double fade_gain(uint64_t index, uint64_t range, int fadetype);
/*
* Process options
*
* Don't do initialization now.
* The 'info' fields are not yet filled in.
*/
static int sox_fade_getopts(sox_effect_t * effp, int argc, char **argv)
{
priv_t * fade = (priv_t *) effp->priv;
char t_char[2];
int t_argno;
uint64_t samples;
const char *n;
--argc, ++argv;
if (argc < 1 || argc > 4)
return lsx_usage(effp);
/* because sample rate is unavailable at this point we store the
* string off for later computations.
*/
if (sscanf(argv[0], "%1[qhltp]", t_char))
{
fade->in_fadetype = *t_char;
fade->out_fadetype = *t_char;
argv++;
argc--;
}
else
{
/* No type given. */
fade->in_fadetype = 'l';
fade->out_fadetype = 'l';
}
fade->in_stop_str = lsx_strdup(argv[0]);
/* Do a dummy parse to see if it will fail */
n = lsx_parsesamples(0., fade->in_stop_str, &samples, 't');
if (!n || *n)
return lsx_usage(effp);
fade->in_stop = samples;
fade->out_start_str = fade->out_stop_str = 0;
for (t_argno = 1; t_argno < argc && t_argno < 3; t_argno++)
{
/* See if there is fade-in/fade-out times/curves specified. */
if(t_argno == 1)
{
fade->out_stop_str = lsx_strdup(argv[t_argno]);
/* Do a dummy parse to see if it will fail */
n = lsx_parseposition(0., fade->out_stop_str, NULL, (uint64_t)0, (uint64_t)0, '=');
if (!n || *n)
return lsx_usage(effp);
fade->out_stop = samples;
}
else
{
fade->out_start_str = lsx_strdup(argv[t_argno]);
/* Do a dummy parse to see if it will fail */
n = lsx_parsesamples(0., fade->out_start_str, &samples, 't');
if (!n || *n)
return lsx_usage(effp);
fade->out_start = samples;
}
} /* End for(t_argno) */
return(SOX_SUCCESS);
}
/*
* Prepare processing.
* Do all initializations.
*/
static int sox_fade_start(sox_effect_t * effp)
{
priv_t * fade = (priv_t *) effp->priv;
sox_bool truncate = sox_false;
uint64_t samples;
uint64_t in_length = effp->in_signal.length != SOX_UNKNOWN_LEN ?
effp->in_signal.length / effp->in_signal.channels : SOX_UNKNOWN_LEN;
/* converting time values to samples */
fade->in_start = 0;
if (lsx_parsesamples(effp->in_signal.rate, fade->in_stop_str,
&samples, 't') == NULL)
return lsx_usage(effp);
fade->in_stop = samples;
fade->do_out = 0;
/* See if user specified a stop time */
if (fade->out_stop_str)
{
fade->do_out = 1;
if (!lsx_parseposition(effp->in_signal.rate, fade->out_stop_str,
&samples, (uint64_t)0, in_length, '=') ||
samples == SOX_UNKNOWN_LEN) {
lsx_fail("audio length is unknown");
return SOX_EOF;
}
fade->out_stop = samples;
if (!(truncate = !!fade->out_stop)) {
fade->out_stop = effp->in_signal.length != SOX_UNKNOWN_LEN ?
effp->in_signal.length / effp->in_signal.channels :
0;
if (!fade->out_stop) {
lsx_fail("cannot fade out: audio length is neither known nor given");
return SOX_EOF;
}
}
/* See if user wants to fade out. */
if (fade->out_start_str)
{
if (lsx_parsesamples(effp->in_signal.rate, fade->out_start_str,
&samples, 't') == NULL)
return lsx_usage(effp);
/* Fade time is relative to stop time. */
fade->out_start = fade->out_stop - samples;
}
else
/* If user doesn't specify fade out length then
* use same length as input side. This is stored
* in in_stop.
*/
fade->out_start = fade->out_stop - fade->in_stop;
}
else
/* If not specified then user wants to process all
* of file. Use a value of zero to indicate this.
*/
fade->out_stop = 0;
if (fade->out_start) { /* Sanity check */
if (fade->in_stop > fade->out_start)
--fade->in_stop; /* 1 sample grace for rounding error. */
if (fade->in_stop > fade->out_start) {
lsx_fail("fade-out overlaps fade-in");
return SOX_EOF;
}
}
fade->samplesdone = fade->in_start;
fade->endpadwarned = 0;
lsx_debug("in_start = %" PRIu64 " in_stop = %" PRIu64 " "
"out_start = %" PRIu64 " out_stop = %" PRIu64,
fade->in_start, fade->in_stop, fade->out_start, fade->out_stop);
if (fade->in_start == fade->in_stop && !truncate &&
fade->out_start == fade->out_stop)
return SOX_EFF_NULL;
effp->out_signal.length = truncate ?
fade->out_stop * effp->in_signal.channels : effp->in_signal.length;
return SOX_SUCCESS;
}
/*
* Processed signed long samples from ibuf to obuf.
* Return number of samples processed.
*/
static int sox_fade_flow(sox_effect_t * effp, const sox_sample_t *ibuf, sox_sample_t *obuf,
size_t *isamp, size_t *osamp)
{
priv_t * fade = (priv_t *) effp->priv;
/* len is total samples, chcnt counts channels */
int len = 0, t_output = 1, more_output = 1;
sox_sample_t t_ibuf;
size_t chcnt = 0;
len = ((*isamp > *osamp) ? *osamp : *isamp);
*osamp = 0;
*isamp = 0;
for(; len && more_output; len--)
{
t_ibuf = *ibuf;
if ((fade->samplesdone >= fade->in_start) &&
(!fade->do_out || fade->samplesdone < fade->out_stop))
{ /* something to generate output */
if (fade->samplesdone < fade->in_stop)
{ /* fade-in phase, increase gain */
*obuf = t_ibuf *
fade_gain(fade->samplesdone - fade->in_start,
fade->in_stop - fade->in_start,
fade->in_fadetype);
} /* endif fade-in */
else if (!fade->do_out || fade->samplesdone < fade->out_start)
{ /* steady gain phase */
*obuf = t_ibuf;
} /* endif steady phase */
else
{ /* fade-out phase, decrease gain */
*obuf = t_ibuf *
fade_gain(fade->out_stop - fade->samplesdone,
fade->out_stop - fade->out_start,
fade->out_fadetype);
} /* endif fade-out */
if (!(!fade->do_out || fade->samplesdone < fade->out_stop))
more_output = 0;
t_output = 1;
}
else
{ /* No output generated */
t_output = 0;
} /* endif something to output */
*isamp += 1;
ibuf++;
if (t_output)
{ /* Output generated, update pointers and counters */
obuf++;
*osamp += 1;
} /* endif t_output */
/* Process next channel */
chcnt++;
if (chcnt >= effp->in_signal.channels)
{ /* all channels of this sample processed */
chcnt = 0;
fade->samplesdone += 1;
} /* endif all channels */
} /* endfor */
/* If not more samples will be returned, let application know
* this.
*/
if (fade->do_out && fade->samplesdone >= fade->out_stop)
return SOX_EOF;
else
return SOX_SUCCESS;
}
/*
* Drain out remaining samples if the effect generates any.
*/
static int sox_fade_drain(sox_effect_t * effp, sox_sample_t *obuf, size_t *osamp)
{
priv_t * fade = (priv_t *) effp->priv;
int len;
size_t t_chan = 0;
len = *osamp;
len -= len % effp->in_signal.channels;
*osamp = 0;
if (fade->do_out && fade->samplesdone < fade->out_stop &&
!(fade->endpadwarned))
{ /* Warning about padding silence into end of sample */
lsx_warn("End time past end of audio. Padding with silence");
fade->endpadwarned = 1;
} /* endif endpadwarned */
for (;len && (fade->do_out &&
fade->samplesdone < fade->out_stop); len--)
{
*obuf = 0;
obuf++;
*osamp += 1;
t_chan++;
if (t_chan >= effp->in_signal.channels)
{
fade->samplesdone += 1;
t_chan = 0;
} /* endif channels */
} /* endfor */
if (fade->do_out && fade->samplesdone >= fade->out_stop)
return SOX_EOF;
else
return SOX_SUCCESS;
}
/*
* Do anything required when you stop reading samples.
* (free allocated memory, etc.)
*/
static int lsx_kill(sox_effect_t * effp)
{
priv_t * fade = (priv_t *) effp->priv;
free(fade->in_stop_str);
free(fade->out_start_str);
free(fade->out_stop_str);
return (SOX_SUCCESS);
}
/* Function returns gain value 0.0 - 1.0 according index / range ratio
* and -1.0 if type is invalid
* todo: to optimize performance calculate gain every now and then and interpolate */
static double fade_gain(uint64_t index, uint64_t range, int type)
{
double retval = 0.0, findex = 0.0;
/* TODO: does it really have to be contrained to [0.0, 1.0]? */
findex = max(0.0, min(1.0, 1.0 * index / range));
switch (type) {
case FADE_TRI : /* triangle */
retval = findex;
break;
case FADE_QUARTER : /* quarter of sinewave */
retval = sin(findex * M_PI / 2);
break;
case FADE_HALF : /* half of sinewave... eh cosine wave */
retval = (1 - cos(findex * M_PI )) / 2 ;
break;
case FADE_LOG : /* logarithmic */
/* 5 means 100 db attenuation. */
/* TODO: should this be adopted with bit depth */
retval = pow(0.1, (1 - findex) * 5);
break;
case FADE_PAR : /* inverted parabola */
retval = (1 - (1 - findex) * (1 - findex));
break;
/* TODO: more fade curves? */
default : /* Error indicating wrong fade curve */
retval = -1.0;
break;
}
return retval;
}
static sox_effect_handler_t sox_fade_effect = {
"fade",
"[ type ] fade-in-length [ stop-position [ fade-out-length ] ]\n"
" Time is in hh:mm:ss.frac format.\n"
" Fade type one of q, h, t, l or p.",
SOX_EFF_MCHAN | SOX_EFF_LENGTH,
sox_fade_getopts,
sox_fade_start,
sox_fade_flow,
sox_fade_drain,
NULL,
lsx_kill, sizeof(priv_t)
};
const sox_effect_handler_t *lsx_fade_effect_fn(void)
{
return &sox_fade_effect;
}