ref: f0230901289e423cd58430d51b9e60951b3f1417
dir: /src/fade.c/
/* This code is based in skel.c
* Written by Chris Bagwell (cbagwell@sprynet.com) - March 16, 1999
* Non-skel parts written by
* Ari Moisio <armoi@sci.fi> Aug 29 2000.
*
* 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.
*/
/* Time resolution one millisecond */
#define TIMERES 1000
/* 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 <math.h>
#include "st.h"
/* Private data for fade file */
typedef struct fadestuff
{ /* These are measured as samples */
ULONG in_start, in_stop, out_start, out_stop, samplesdone;
char in_fadetype, out_fadetype;
int endpadwarned;
} *fade_t;
#define FADE_USAGE "Usage: fade [ type ] fade-in-length [ stop-time [ fade-out-length ] ]\nTimes in seconds.\nFade type one of q, h, t, l or p.\n"
/* prototypes */
static double fade_gain(ULONG index, ULONG range, char fadetype);
/*
* Process options
*
* Don't do initialization now.
* The 'info' fields are not yet filled in.
*/
int st_fade_getopts(effp, n, argv)
eff_t effp;
int n;
char **argv;
{
fade_t fade = (fade_t) effp->priv;
double t_double;
char t_char;
int t_argno;
if (n < 1 || n > 4)
{ /* Wrong number of arguments. */
st_fail(FADE_USAGE);
return(ST_EOF);
}
/* because sample rate is unavailable at this point we convert time
* values to seconds * TIMERES and convert them to samples later.
*/
if (sscanf(argv[0], "%1[qhltp]", &t_char))
{
fade->in_fadetype = t_char;
fade->out_fadetype = t_char;
argv++;
n--;
}
else
{
/* No type given. */
fade->in_fadetype = 'l';
fade->out_fadetype = 'l';
}
t_double = st_parsetime(argv[0]);
if (t_double >= 0)
{ /* got something numerical */
/* Don't support in_start. Its job is done by trim effect */
fade->in_start = 0;
fade->in_stop = t_double * TIMERES;
}
else
{ /* unnumeric value */
st_fail(FADE_USAGE);
return(ST_EOF);
} /* endif numeric fade-in */
fade->out_start = fade->out_stop = 0;
for (t_argno = 1; t_argno < n && t_argno <= 3; t_argno++)
{ /* See if there is fade-in/fade-out times/curves specified. */
t_double = st_parsetime(argv[t_argno]);
if (t_double >= 0)
{
if (t_argno == 1)
{
fade->out_stop = t_double * TIMERES;
/* Zero fade-out too */
fade->out_start = fade->out_stop;
}
else
{
fade->out_start = fade->out_stop - t_double * TIMERES;
}
}
else
{
st_fail(FADE_USAGE);
return(ST_EOF);
}
} /* End for(t_argno) */
/* Sanity check for fade times vs total time */
if (fade->in_stop > fade->out_start && fade->out_start != 0)
{ /* Fades too long */
st_fail("Fade: End of fade-in should not happen before beginning of fade-out");
return(ST_EOF);
} /* endif fade time sanity */
return(ST_SUCCESS);
}
/*
* Prepare processing.
* Do all initializations.
*/
void st_fade_start(effp)
eff_t effp;
{
fade_t fade = (fade_t) effp->priv;
/* converting time values to samples */
fade->in_start = (double)fade->in_start * effp->ininfo.rate / TIMERES;
fade->in_stop = (double)fade->in_stop * effp->ininfo.rate / TIMERES;
fade->out_start = (double)fade->out_start * effp->ininfo.rate / TIMERES;
fade->out_stop = (double)fade->out_stop * effp->ininfo.rate / TIMERES;
/* If lead-in is required it is handled as negative sample numbers */
fade->samplesdone = (fade->in_start < 0 ? fade->in_start :0);
fade->endpadwarned = 0;
}
/*
* Processed signed long samples from ibuf to obuf.
* Return number of samples processed.
*/
void st_fade_flow(effp, ibuf, obuf, isamp, osamp)
eff_t effp;
LONG *ibuf, *obuf;
int *isamp, *osamp;
{
fade_t fade = (fade_t) effp->priv;
/* len is total samples, chcnt counts channels */
int len = 0, chcnt = 0, t_output = 0;
LONG t_ibuf;
len = ((*isamp > *osamp) ? *osamp : *isamp);
*osamp = 0;
*isamp = 0;
for(; len; len--)
{
t_ibuf = (fade->samplesdone < 0 ? 0 : *ibuf);
if ((fade->samplesdone >= fade->in_start) &&
(fade->out_stop == 0 || 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 */
if (fade->samplesdone >= fade->in_stop &&
(fade->out_start == 0 || fade->samplesdone < fade->out_start))
{ /* steady gain phase */
*obuf = t_ibuf;
} /* endif steady phase */
if (fade->out_start != 0 && fade->samplesdone >= fade->out_start)
{ /* 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 */
t_output = 1;
}
else
{ /* No output generated */
t_output = 0;
} /* endif something to output */
if (fade->samplesdone >= 0 )
{ /* Something to input */
*isamp += 1;
ibuf++;
} /* endif something accepted as input */
if (t_output)
{ /* Output generated, update pointers and counters */
obuf++;
*osamp += 1;
} /* endif t_output */
/* Process next channel */
chcnt++;
if (chcnt >= effp->ininfo.channels)
{ /* all channels of this sample processed */
chcnt = 0;
fade->samplesdone += 1;
} /* endif all channels */
} /* endfor */
}
/*
* Drain out remaining samples if the effect generates any.
*/
void st_fade_drain(effp, obuf, osamp)
eff_t effp;
LONG *obuf;
int *osamp;
{
fade_t fade = (fade_t) effp->priv;
int len, t_chan = 0;
len = *osamp;
*osamp = 0;
if (fade->out_stop != 0 && fade->samplesdone < fade->out_stop &&
!(fade->endpadwarned))
{ /* Warning about padding silence into end of sample */
st_warn("Fade: warning: End time passed end-of-file. Padding with silence");
fade->endpadwarned = 1;
} /* endif endpadwarned */
for (;len && (fade->out_stop != 0 &&
fade->samplesdone < fade->out_stop); len--)
{
*obuf = 0;
obuf++;
*osamp += 1;
t_chan++;
if (t_chan >= effp->ininfo.channels)
{
fade->samplesdone += 1;
t_chan = 0;
} /* endif channels */
} /* endfor */
}
/*
* Do anything required when you stop reading samples.
* (free allocated memory, etc.)
*/
void st_fade_stop(effp)
eff_t effp;
{
/* nothing to do */
}
/* 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(index, range, type)
ULONG index, range;
char type;
{
double retval = 0.0, findex = 0.0;
findex = 1.0 * index / range;
/* todo: are these really needed */
findex = (findex < 0 ? 0.0 : findex);
findex = (findex > 1.0 ? 1.0 : findex);
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 : /* logaritmic */
/* 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;
} /* endswitch */
return retval;
}