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/*
follow.c:
Copyright (C) 1994, 1999 Paris Smaragdis, John ffitch
This file is part of Csound.
The Csound 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.
Csound 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 Csound; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02110-1301 USA
*/
/* Envelope follower by Paris Smaragdis */
/* Berklee College of Music Csound development team */
/* Copyright (c) August 1994. All rights reserve */
/* Improvements 1999 John ffitch */
#include "stdopcod.h"
#include <math.h>
#include "follow.h"
static int32_t flwset(CSOUND *csound, FOL *p)
{
p->wgh = p->max = FL(0.0);
p->length = (int32)(*p->len * CS_ESR);
if (UNLIKELY(p->length<=0L)) { /* RWD's suggestion */
csound->Warning(csound, Str("follow - zero length!"));
p->length = (int32)CS_ESR;
}
p->count = p->length;
return OK;
}
/* Use absolute value rather than max/min */
static int32_t follow(CSOUND *csound, FOL *p)
{
IGN(csound);
uint32_t offset = p->h.insdshead->ksmps_offset;
uint32_t early = p->h.insdshead->ksmps_no_end;
uint32_t n, nsmps = CS_KSMPS;
MYFLT *in = p->in, *out = p->out;
MYFLT max = p->max;
int32 count = p->count;
if (UNLIKELY(offset)) memset(out, '\0', offset*sizeof(MYFLT));
if (UNLIKELY(early)) {
nsmps -= early;
memset(&out[nsmps], '\0', early*sizeof(MYFLT));
}
for (n=offset; n<nsmps; n++) {
MYFLT sig = FABS(in[n]);
if (sig > max) max = sig;
if (UNLIKELY(--count == 0L)) {
p->wgh = max;
max = FL(0.0);
count = p->length;
}
out[n] = p->wgh;
}
p->max = max;
p->count = count;
return OK;
}
/* The Jean-Marc Jot (IRCAM) envelope follower, from code by
Bram.DeJong@rug.ac.be and James Maccartney posted on music-dsp;
Transferred to csound by JPff, 2000 feb 12
*/
static int32_t envset(CSOUND *csound, ENV *p)
{
/* Note - 6.90775527898 -- log(0.001) */
p->lastatt = *p->attack;
if (p->lastatt<=FL(0.0))
p->ga = EXP(- FL(69.0775527898)*csound->onedsr);
else
p->ga = EXP(- FL(6.90775527898)/(CS_ESR* p->lastatt));
p->lastrel = *p->release;
if (p->lastrel<=FL(0.0))
p->gr = EXP(- FL(69.0775527898)*csound->onedsr);
else
p->gr = EXP(- FL(6.90775527898)/(CS_ESR* p->lastrel));
p->envelope = FL(0.0);
return OK;
}
static int32_t envext(CSOUND *csound, ENV *p)
{
uint32_t offset = p->h.insdshead->ksmps_offset;
uint32_t early = p->h.insdshead->ksmps_no_end;
uint32_t n, nsmps = CS_KSMPS;
MYFLT envelope = p->envelope;
MYFLT ga, gr;
MYFLT *in = p->in, *out = p->out;
if (p->lastatt!=*p->attack) {
p->lastatt = *p->attack;
if (p->lastatt<=FL(0.0))
ga = p->ga = EXP(- FL(69.0775527898)*csound->onedsr);
// EXP(-FL(10000.0)*csound->onedsr);
else
ga = p->ga = EXP(- FL(6.90775527898)/(CS_ESR* p->lastatt));
//EXP(-FL(1.0)/(CS_ESR* p->lastatt));
}
else ga = p->ga;
if (p->lastrel!=*p->release) {
p->lastrel = *p->release;
if (p->lastrel<=FL(0.0))
gr = p->gr = EXP(- FL(69.0775527898)*csound->onedsr);
//EXP(-FL(100.0)*csound->onedsr);
else
gr = p->gr = EXP(- FL(6.90775527898)/(CS_ESR* p->lastrel));
//EXP(-FL(1.0)/(CS_ESR* p->lastrel));
}
else gr = p->gr;
if (UNLIKELY(offset)) memset(out, '\0', offset*sizeof(MYFLT));
if (UNLIKELY(early)) {
nsmps -= early;
memset(&out[nsmps], '\0', early*sizeof(MYFLT));
}
for (n=offset;n<nsmps;n++) {
MYFLT inp = FABS(in[n]); /* Absolute value */
if (envelope < inp) {
envelope = inp + ga*(envelope-inp);
}
else {
envelope = inp + gr*(envelope-inp);
}
out[n] = envelope;
}
p->envelope = envelope;
return OK;
}
#define S(x) sizeof(x)
static OENTRY localops[] = {
{ "follow", S(FOL), 0, 3, "a", "ai", (SUBR)flwset, (SUBR)follow },
{ "follow2", S(ENV), 0, 3, "a", "akk", (SUBR)envset, (SUBR)envext }
};
int32_t follow_init_(CSOUND *csound)
{
return csound->AppendOpcodes(csound, &(localops[0]),
(int32_t
) (sizeof(localops) / sizeof(OENTRY)));
}
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