/
filter_templates.h
193 lines (170 loc) · 5.6 KB
/
filter_templates.h
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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
/*
* Extended Audio Converter for SDL (Simple DirectMedia Layer)
* Copyright (C) 2002 Frank Ranostaj
* Institute of Applied Physik
* Johann Wolfgang Goethe-Universität
* Frankfurt am Main, Germany
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Frank Ranostaj
* ranostaj@stud.uni-frankfurt.de
*
* (This code blatantly abducted for SDL_sound. Thanks, Frank! --ryan.)
*/
#ifndef Suffix
#error include filter_template.h with defined Suffix macro!
#else
#define CH(x) (Suffix((x)*))
/*-------------------------------------------------------------------------*/
/* this filter (Kaiser-window beta=6.8) gives a decent -80dB attentuation */
/*-------------------------------------------------------------------------*/
#define sum_d(v,dx) ((int) v[CH(dx)] + v[CH(1-dx)])
static Sint16* Suffix(doubleRate)( Sint16 *outp, Sint16 *inp, int length,
VarFilter* filt, int* cpos )
{
int out;
Sint16 *to;
to = inp - length;
while( inp > to )
{
out = 0;
out-= 9 * sum_d( inp, 16);
out+= 23 * sum_d( inp, 15);
out-= 46 * sum_d( inp, 14);
out+= 83 * sum_d( inp, 13);
out-= 138 * sum_d( inp, 12);
out+= 217 * sum_d( inp, 11);
out-= 326 * sum_d( inp, 10);
out+= 474 * sum_d( inp, 9);
out-= 671 * sum_d( inp, 8);
out+= 936 * sum_d( inp, 7);
out-= 1295 * sum_d( inp, 6);
out+= 1800 * sum_d( inp, 5);
out-= 2560 * sum_d( inp, 4);
out+= 3863 * sum_d( inp, 3);
out-= 6764 * sum_d( inp, 2);
out+= 20798 * sum_d( inp, 1);
outp[CH(1)] = ( 32770 * inp[CH(1)] + out) >> 16;
outp[CH(0)] = ( 32770 * inp[CH(0)] + out) >> 16;
inp -= CH(1);
outp -= CH(2);
}
return outp;
}
#undef sum_d
/*-------------------------------------------------------------------------*/
#define sum_h(v,dx) ((int) v[CH(dx)] + v[CH(-dx)])
static Sint16* Suffix(halfRate)( Sint16 *outp, Sint16 *inp, int length,
VarFilter* filt, int* cpos )
{
int out;
Sint16* to;
to = inp + length;
while( inp < to )
{
out = 0;
out-= 9 * sum_h( inp, 31);
out+= 23 * sum_h( inp, 29);
out-= 46 * sum_h( inp, 27);
out+= 83 * sum_h( inp, 25);
out-= 138 * sum_h( inp, 23);
out+= 217 * sum_h( inp, 21);
out-= 326 * sum_h( inp, 19);
out+= 474 * sum_h( inp, 17);
out-= 671 * sum_h( inp, 15);
out+= 936 * sum_h( inp, 13);
out-= 1295 * sum_h( inp, 11);
out+= 1800 * sum_h( inp, 9);
out-= 2560 * sum_h( inp, 7);
out+= 3863 * sum_h( inp, 5);
out-= 6764 * sum_h( inp, 3);
out+= 20798 * sum_h( inp, 1);
out+= 32770 * (int)inp[0];
outp[0] = out >> 16;
inp+= CH(2);
outp += CH(1);
}
return outp;
}
#undef sum_h
/*-------------------------------------------------------------------------*/
static Sint16* Suffix(increaseRate)( Sint16 *outp, Sint16 *inp, int length,
VarFilter* filter, int* cpos )
{
const static int fsize = CH(2*_fsize);
Sint16 *f;
int out;
int i, pos;
Sint16* to;
inp -= fsize;
to = inp - length;
pos = *cpos;
while( inp > to )
{
out = 0;
f = filter->c[pos];
for( i = _fsize + 1; --i; inp+=CH(4), f+=4 )
{
out+= f[0] * (int)inp[CH(0)];
out+= f[1] * (int)inp[CH(1)];
out+= f[2] * (int)inp[CH(2)];
out+= f[3] * (int)inp[CH(3)];
}
outp[0] = out >> 16;
pos = ( pos + filter->ratio.denominator - 1 )
% filter->ratio.denominator;
inp -= CH( 4 * _fsize );
inp -= CH( filter->incr[pos] );
outp -= CH(1);
}
*cpos = pos;
return outp;
}
/*-------------------------------------------------------------------------*/
static Sint16* Suffix(decreaseRate)( Sint16 *outp, Sint16 *inp, int length,
VarFilter* filter, int* cpos )
{
const static int fsize = CH(2*_fsize);
Sint16 *f;
int out;
int i, pos;
Sint16 *to;
inp -= fsize;
to = inp + length;
pos = *cpos;
while( inp < to )
{
out = 0;
f = filter->c[pos];
for( i = _fsize + 1; --i; inp+=CH(4), f+=4 )
{
out+= f[0] * (int)inp[CH(0)];
out+= f[1] * (int)inp[CH(1)];
out+= f[2] * (int)inp[CH(2)];
out+= f[3] * (int)inp[CH(3)];
}
outp[0] = out >> 16;
inp -= CH( 4 * _fsize );
inp += CH( filter->incr[pos] );
outp += CH(1);
pos = ( pos + 1 ) % filter->ratio.denominator;
}
*cpos = pos;
return outp;
}
/*-------------------------------------------------------------------------*/
#undef CH
#endif /* Suffix */