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
|
/*
cw_binaural~: a binaural synthesis external for pure data
by David Doukhan - david.doukhan@gmail.com - http://perso.limsi.fr/doukhan
and Anne Sedes - sedes.anne@gmail.com
Copyright (C) 2009-2011 David Doukhan and Anne Sedes
For more details, see CW_binaural~, a binaural synthesis external for Pure Data
David Doukhan and Anne Sedes, PDCON09
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <math.h>
#include <m_pd.h> //needed for fft implementation
#include "minphase_hrtfcont.hpp"
#include "flyweight_ir_factory.hpp"
MinPhaseHrtfCont::MinPhaseHrtfCont(const ir_key&k):
HrtfCont(k)
{
ir_key k2 = k;
// set impulse response length
_ir_length = k.length;
// FIXME: IR size verification ??? => power of 2
// get the container storing the coresponding temporal impulse response
k2.minp_ap_dec = false;
HrtfCont* hc = FlyweightIrFactory::instance()->hrtf_set_get(k2);
// iterate on the container storing the temporal impulse response
for (angle1_cit ie = hc->map_get()->begin(); ie != hc->map_get()->end(); ie++)
for (angle2_cit ia2 = ie->second.begin(); ia2 != ie->second.end(); ia2++)
{
// current azimuth and elevation
const float el = ie->first;
const float az = ia2->first;
// allocate buffers
float *lbuf = _m[el][az].lbuf = new float[_ir_length];
float *rbuf = _m[el][az].rbuf = new float[_ir_length];
minphase_ir(ia2->second.lbuf, lbuf, _ir_length);
minphase_ir(ia2->second.rbuf, rbuf, _ir_length);
}
}
// store in dst the magnitude of spectrum src of size n
// assumption: src is the specetrum of a real signal
void MinPhaseHrtfCont::magnitude(const float* src, float* dst, size_t n)
{
for (size_t i = 1; i < n/2; ++i)
{
dst[i] = sqrt(src[i]*src[i] + src[n-i] * src[n-i]);
dst[n -i] = dst[i];
}
dst[0] = src[0] >= 0 ? src[0] : -src[0];
dst[n/2] = src[n/2] >= 0 ? src[n/2] : -src[n/2];
}
// store in dst the imaginary part of hilbert transform
// applied to signal src of size n
void MinPhaseHrtfCont::im_hilbert(const float* src, float* dst, size_t n)
{
size_t i;
float tmp;
if (dst != src)
for (i = 0; i < n; ++i)
dst[i] = src[i];
mayer_realfft(n, dst);
for (i = 1; i < n/2; ++i)
{
tmp = dst[i];
dst[i] = -dst[n -i];
dst[n-i] = tmp;
}
dst[0] = dst[n/2] = 0;
mayer_realifft(n, dst);
for (i = 0; i < n; ++i)
dst[i] /= n;
}
// store in dst the minphase impulse response corresponding to src
void MinPhaseHrtfCont::minphase_ir(const float* src, float* dst, int n)
{
float *sig_spectrum = new float[n];
float *magn, *phase;
int i;
// compute the spectrum from input signal
for (i = 0; i < n; ++i)
sig_spectrum[i] = src[i];
mayer_realfft(n, sig_spectrum);
// get the magnitude of the spectrum => symetric signal
magn = new float[n];
magnitude(sig_spectrum, magn, n);
// compute hilbert transform of the log of the magnitude
// this computation correspond to the minimum phase
phase = new float[n];
for (i = 0; i < n; ++i)
phase[i] = -log(magn[i]);
im_hilbert(phase, phase, n);
float* real = new float[n];
float* imag = new float[n];
for (i = 0; i < n; ++i)
{
real[i] = magn[i] * cos(phase[i]);
imag[i] = magn[i] * sin(phase[i]);
}
mayer_ifft(n, real, imag);
delete [] sig_spectrum;
delete [] imag;
delete [] magn;
delete [] phase;
for (i = 0; i < n; ++i)
dst[i] = real[i] /= n;
delete [] real;
}
|
