1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
/*
dam.c:
Copyright (C) 1997 Marc Resibois
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
*/
#include "stdopcod.h"
#include "dam.h"
#include <math.h>
/*
* Dynamic Amplitude Modifier.
*
* (C) Marc Resibois 1997
*
* I place this source code in the public domain. Just
* let me know if you do something you like with it ;-)
*
* For bugs, question, please write to Marc.Resibois@ping.be
*/
/*
* Initialisation code
*/
static int32_t daminit(CSOUND *csound, DAM *p)
{
/* Initialise gain value */
p->gain = FL(1.0);
/* Compute the gain speed changes from parameter given by Csound */
/* the computed values are stored in the opcode data structure p */
/* for later use in the main processing */
p->rspeed = (*p->rtime)*csound->onedsr*FL(1000.0);
p->fspeed = (*p->ftime)*csound->onedsr*FL(1000.0);
p->kthr = -FL(1.0);
return OK;
}
/*
* Run-time computation code
*/
static int32_t dam(CSOUND *csound, DAM *p)
{
IGN(csound);
MYFLT *ain,*aout;
MYFLT threshold;
MYFLT gain;
MYFLT comp1,comp2;
MYFLT *powerPos;
MYFLT *powerBuffer;
MYFLT power;
MYFLT tg;
uint32_t offset = p->h.insdshead->ksmps_offset;
uint32_t early = p->h.insdshead->ksmps_no_end;
uint32_t i, nsmps = CS_KSMPS;
/* Initialize power value and buffer at first ksamp computed as
* it depends on kthreshold
*/
if (p->kthr < FL(0.0)) {
MYFLT x = (p->kthr = *(p->kthreshold))/(MYFLT)POWER_BUFSIZE;
p->power = p->kthr;
/* Initialise table as threshhold changed */
for (i=0;i<POWER_BUFSIZE;i++) {
p->powerBuffer[i] = x;
}
p->powerPos = p->powerBuffer;
}
ain = p->ain;
aout = p->aout;
threshold = *(p->kthreshold);
gain = p->gain;
comp1 = *(p->icomp1);
comp2 = *(p->icomp2);
powerPos = p->powerPos;
powerBuffer = p->powerBuffer;
power = p->power;
/* Process ksmps samples */
if (UNLIKELY(offset)) memset(aout, '\0', offset*sizeof(MYFLT));
if (UNLIKELY(early)) {
nsmps -= early;
memset(&aout[nsmps], '\0', early*sizeof(MYFLT));
}
for (i=offset;i<nsmps;i++) {
/* Estimates the current power level */
*powerPos = FABS(ain[i])/(MYFLT)(POWER_BUFSIZE*ROOT2);
power += (*powerPos++);
if ((powerPos-powerBuffer)==POWER_BUFSIZE) {
powerPos = p->powerBuffer;
}
power -= (*powerPos);
/* Looks where the power is related to the threshold
and compute target gain */
if (power>threshold) {
tg = ((power-threshold)*comp1+threshold)/power;
}
else {
tg = threshold*(POWER((power/threshold),
FL(1.0)/comp2))/power;
}
/* move gain toward target */
if (gain<tg) {
gain += p->rspeed;
}
else {
gain -= p->fspeed;
}
/* compute output */
aout[i] = ain[i]*gain;
}
/* Store the last gain value for next call */
p->gain = gain;
p->power = power;
p->powerPos = powerPos;
return OK;
}
#define S(x) sizeof(x)
static OENTRY localops[] = {
{ "dam", S(DAM), 0, 3, "a", "akiiii",(SUBR)daminit, (SUBR)dam },
};
int32_t dam_init_(CSOUND *csound)
{
return csound->AppendOpcodes(csound, &(localops[0]),
(int32_t
) (sizeof(localops) / sizeof(OENTRY)));
}
|
