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
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
|
/*
** FFT and FHT routines
** Copyright 1988, 1993; Ron Mayer
**
** fht(fz,n);
** Does a hartley transform of "n" points in the array "fz".
**
** NOTE: This routine uses at least 2 patented algorithms, and may be
** under the restrictions of a bunch of different organizations.
** Although I wrote it completely myself; it is kind of a derivative
** of a routine I once authored and released under the GPL, so it
** may fall under the free software foundation's restrictions;
** it was worked on as a Stanford Univ project, so they claim
** some rights to it; it was further optimized at work here, so
** I think this company claims parts of it. The patents are
** held by R. Bracewell (the FHT algorithm) and O. Buneman (the
** trig generator), both at Stanford Univ.
** If it were up to me, I'd say go do whatever you want with it;
** but it would be polite to give credit to the following people
** if you use this anywhere:
** Euler - probable inventor of the fourier transform.
** Gauss - probable inventor of the FFT.
** Hartley - probable inventor of the hartley transform.
** Buneman - for a really cool trig generator
** Mayer(me) - for authoring this particular version and
** including all the optimizations in one package.
** Thanks,
** Ron Mayer; mayer@acuson.com
**
*/
#include <math.h>
#define FLOAT float
#define SQRT2 1.4142135623730951454746218587388284504414
void fft(FLOAT *x_real, FLOAT *x_imag, FLOAT *energy, FLOAT *phi, int N);
void fft2(FLOAT *x_real, FLOAT *energy, int N);
static FLOAT costab[20]=
{
.00000000000000000000000000000000000000000000000000,
.70710678118654752440084436210484903928483593768847,
.92387953251128675612818318939678828682241662586364,
.98078528040323044912618223613423903697393373089333,
.99518472667219688624483695310947992157547486872985,
.99879545620517239271477160475910069444320361470461,
.99969881869620422011576564966617219685006108125772,
.99992470183914454092164649119638322435060646880221,
.99998117528260114265699043772856771617391725094433,
.99999529380957617151158012570011989955298763362218,
.99999882345170190992902571017152601904826792288976,
.99999970586288221916022821773876567711626389934930,
.99999992646571785114473148070738785694820115568892,
.99999998161642929380834691540290971450507605124278,
.99999999540410731289097193313960614895889430318945,
.99999999885102682756267330779455410840053741619428
};
static FLOAT sintab[20]=
{
1.0000000000000000000000000000000000000000000000000,
.70710678118654752440084436210484903928483593768846,
.38268343236508977172845998403039886676134456248561,
.19509032201612826784828486847702224092769161775195,
.09801714032956060199419556388864184586113667316749,
.04906767432741801425495497694268265831474536302574,
.02454122852291228803173452945928292506546611923944,
.01227153828571992607940826195100321214037231959176,
.00613588464915447535964023459037258091705788631738,
.00306795676296597627014536549091984251894461021344,
.00153398018628476561230369715026407907995486457522,
.00076699031874270452693856835794857664314091945205,
.00038349518757139558907246168118138126339502603495,
.00019174759731070330743990956198900093346887403385,
.00009587379909597734587051721097647635118706561284,
.00004793689960306688454900399049465887274686668768
};
/* This is a simplified version for n an even power of 2 */
/* MFC: In the case of LayerII encoding, n==1024 always. */
static void fht(FLOAT *fz)
{
int i,k,k1,k2,k3,k4,kx;
FLOAT *fi,*fn,*gi;
FLOAT t_c,t_s;
FLOAT a;
static const struct
{
unsigned short k1, k2;
}
k1k2tab[8*62] = {
{0x020,0x010},{0x040,0x008},{0x050,0x028},{0x060,0x018},{0x068,0x058},{0x070,0x038},{0x080,0x004},{0x088,0x044},
{0x090,0x024},{0x098,0x064},{0x0a0,0x014},{0x0a4,0x094},{0x0a8,0x054},{0x0b0,0x034},{0x0b8,0x074},{0x0c0,0x00c},
{0x0c4,0x08c},{0x0c8,0x04c},{0x0d0,0x02c},{0x0d4,0x0ac},{0x0d8,0x06c},{0x0e0,0x01c},{0x0e4,0x09c},{0x0e8,0x05c},
{0x0ec,0x0dc},{0x0f0,0x03c},{0x0f4,0x0bc},{0x0f8,0x07c},{0x100,0x002},{0x104,0x082},{0x108,0x042},{0x10c,0x0c2},
{0x110,0x022},{0x114,0x0a2},{0x118,0x062},{0x11c,0x0e2},{0x120,0x012},{0x122,0x112},{0x124,0x092},{0x128,0x052},
{0x12c,0x0d2},{0x130,0x032},{0x134,0x0b2},{0x138,0x072},{0x13c,0x0f2},{0x140,0x00a},{0x142,0x10a},{0x144,0x08a},
{0x148,0x04a},{0x14c,0x0ca},{0x150,0x02a},{0x152,0x12a},{0x154,0x0aa},{0x158,0x06a},{0x15c,0x0ea},{0x160,0x01a},
{0x162,0x11a},{0x164,0x09a},{0x168,0x05a},{0x16a,0x15a},{0x16c,0x0da},{0x170,0x03a},{0x172,0x13a},{0x174,0x0ba},
{0x178,0x07a},{0x17c,0x0fa},{0x180,0x006},{0x182,0x106},{0x184,0x086},{0x188,0x046},{0x18a,0x146},{0x18c,0x0c6},
{0x190,0x026},{0x192,0x126},{0x194,0x0a6},{0x198,0x066},{0x19a,0x166},{0x19c,0x0e6},{0x1a0,0x016},{0x1a2,0x116},
{0x1a4,0x096},{0x1a6,0x196},{0x1a8,0x056},{0x1aa,0x156},{0x1ac,0x0d6},{0x1b0,0x036},{0x1b2,0x136},{0x1b4,0x0b6},
{0x1b8,0x076},{0x1ba,0x176},{0x1bc,0x0f6},{0x1c0,0x00e},{0x1c2,0x10e},{0x1c4,0x08e},{0x1c6,0x18e},{0x1c8,0x04e},
{0x1ca,0x14e},{0x1cc,0x0ce},{0x1d0,0x02e},{0x1d2,0x12e},{0x1d4,0x0ae},{0x1d6,0x1ae},{0x1d8,0x06e},{0x1da,0x16e},
{0x1dc,0x0ee},{0x1e0,0x01e},{0x1e2,0x11e},{0x1e4,0x09e},{0x1e6,0x19e},{0x1e8,0x05e},{0x1ea,0x15e},{0x1ec,0x0de},
{0x1ee,0x1de},{0x1f0,0x03e},{0x1f2,0x13e},{0x1f4,0x0be},{0x1f6,0x1be},{0x1f8,0x07e},{0x1fa,0x17e},{0x1fc,0x0fe},
{0x200,0x001},{0x202,0x101},{0x204,0x081},{0x206,0x181},{0x208,0x041},{0x20a,0x141},{0x20c,0x0c1},{0x20e,0x1c1},
{0x210,0x021},{0x212,0x121},{0x214,0x0a1},{0x216,0x1a1},{0x218,0x061},{0x21a,0x161},{0x21c,0x0e1},{0x21e,0x1e1},
{0x220,0x011},{0x221,0x211},{0x222,0x111},{0x224,0x091},{0x226,0x191},{0x228,0x051},{0x22a,0x151},{0x22c,0x0d1},
{0x22e,0x1d1},{0x230,0x031},{0x232,0x131},{0x234,0x0b1},{0x236,0x1b1},{0x238,0x071},{0x23a,0x171},{0x23c,0x0f1},
{0x23e,0x1f1},{0x240,0x009},{0x241,0x209},{0x242,0x109},{0x244,0x089},{0x246,0x189},{0x248,0x049},{0x24a,0x149},
{0x24c,0x0c9},{0x24e,0x1c9},{0x250,0x029},{0x251,0x229},{0x252,0x129},{0x254,0x0a9},{0x256,0x1a9},{0x258,0x069},
{0x25a,0x169},{0x25c,0x0e9},{0x25e,0x1e9},{0x260,0x019},{0x261,0x219},{0x262,0x119},{0x264,0x099},{0x266,0x199},
{0x268,0x059},{0x269,0x259},{0x26a,0x159},{0x26c,0x0d9},{0x26e,0x1d9},{0x270,0x039},{0x271,0x239},{0x272,0x139},
{0x274,0x0b9},{0x276,0x1b9},{0x278,0x079},{0x27a,0x179},{0x27c,0x0f9},{0x27e,0x1f9},{0x280,0x005},{0x281,0x205},
{0x282,0x105},{0x284,0x085},{0x286,0x185},{0x288,0x045},{0x289,0x245},{0x28a,0x145},{0x28c,0x0c5},{0x28e,0x1c5},
{0x290,0x025},{0x291,0x225},{0x292,0x125},{0x294,0x0a5},{0x296,0x1a5},{0x298,0x065},{0x299,0x265},{0x29a,0x165},
{0x29c,0x0e5},{0x29e,0x1e5},{0x2a0,0x015},{0x2a1,0x215},{0x2a2,0x115},{0x2a4,0x095},{0x2a5,0x295},{0x2a6,0x195},
{0x2a8,0x055},{0x2a9,0x255},{0x2aa,0x155},{0x2ac,0x0d5},{0x2ae,0x1d5},{0x2b0,0x035},{0x2b1,0x235},{0x2b2,0x135},
{0x2b4,0x0b5},{0x2b6,0x1b5},{0x2b8,0x075},{0x2b9,0x275},{0x2ba,0x175},{0x2bc,0x0f5},{0x2be,0x1f5},{0x2c0,0x00d},
{0x2c1,0x20d},{0x2c2,0x10d},{0x2c4,0x08d},{0x2c5,0x28d},{0x2c6,0x18d},{0x2c8,0x04d},{0x2c9,0x24d},{0x2ca,0x14d},
{0x2cc,0x0cd},{0x2ce,0x1cd},{0x2d0,0x02d},{0x2d1,0x22d},{0x2d2,0x12d},{0x2d4,0x0ad},{0x2d5,0x2ad},{0x2d6,0x1ad},
{0x2d8,0x06d},{0x2d9,0x26d},{0x2da,0x16d},{0x2dc,0x0ed},{0x2de,0x1ed},{0x2e0,0x01d},{0x2e1,0x21d},{0x2e2,0x11d},
{0x2e4,0x09d},{0x2e5,0x29d},{0x2e6,0x19d},{0x2e8,0x05d},{0x2e9,0x25d},{0x2ea,0x15d},{0x2ec,0x0dd},{0x2ed,0x2dd},
{0x2ee,0x1dd},{0x2f0,0x03d},{0x2f1,0x23d},{0x2f2,0x13d},{0x2f4,0x0bd},{0x2f5,0x2bd},{0x2f6,0x1bd},{0x2f8,0x07d},
{0x2f9,0x27d},{0x2fa,0x17d},{0x2fc,0x0fd},{0x2fe,0x1fd},{0x300,0x003},{0x301,0x203},{0x302,0x103},{0x304,0x083},
{0x305,0x283},{0x306,0x183},{0x308,0x043},{0x309,0x243},{0x30a,0x143},{0x30c,0x0c3},{0x30d,0x2c3},{0x30e,0x1c3},
{0x310,0x023},{0x311,0x223},{0x312,0x123},{0x314,0x0a3},{0x315,0x2a3},{0x316,0x1a3},{0x318,0x063},{0x319,0x263},
{0x31a,0x163},{0x31c,0x0e3},{0x31d,0x2e3},{0x31e,0x1e3},{0x320,0x013},{0x321,0x213},{0x322,0x113},{0x323,0x313},
{0x324,0x093},{0x325,0x293},{0x326,0x193},{0x328,0x053},{0x329,0x253},{0x32a,0x153},{0x32c,0x0d3},{0x32d,0x2d3},
{0x32e,0x1d3},{0x330,0x033},{0x331,0x233},{0x332,0x133},{0x334,0x0b3},{0x335,0x2b3},{0x336,0x1b3},{0x338,0x073},
{0x339,0x273},{0x33a,0x173},{0x33c,0x0f3},{0x33d,0x2f3},{0x33e,0x1f3},{0x340,0x00b},{0x341,0x20b},{0x342,0x10b},
{0x343,0x30b},{0x344,0x08b},{0x345,0x28b},{0x346,0x18b},{0x348,0x04b},{0x349,0x24b},{0x34a,0x14b},{0x34c,0x0cb},
{0x34d,0x2cb},{0x34e,0x1cb},{0x350,0x02b},{0x351,0x22b},{0x352,0x12b},{0x353,0x32b},{0x354,0x0ab},{0x355,0x2ab},
{0x356,0x1ab},{0x358,0x06b},{0x359,0x26b},{0x35a,0x16b},{0x35c,0x0eb},{0x35d,0x2eb},{0x35e,0x1eb},{0x360,0x01b},
{0x361,0x21b},{0x362,0x11b},{0x363,0x31b},{0x364,0x09b},{0x365,0x29b},{0x366,0x19b},{0x368,0x05b},{0x369,0x25b},
{0x36a,0x15b},{0x36b,0x35b},{0x36c,0x0db},{0x36d,0x2db},{0x36e,0x1db},{0x370,0x03b},{0x371,0x23b},{0x372,0x13b},
{0x373,0x33b},{0x374,0x0bb},{0x375,0x2bb},{0x376,0x1bb},{0x378,0x07b},{0x379,0x27b},{0x37a,0x17b},{0x37c,0x0fb},
{0x37d,0x2fb},{0x37e,0x1fb},{0x380,0x007},{0x381,0x207},{0x382,0x107},{0x383,0x307},{0x384,0x087},{0x385,0x287},
{0x386,0x187},{0x388,0x047},{0x389,0x247},{0x38a,0x147},{0x38b,0x347},{0x38c,0x0c7},{0x38d,0x2c7},{0x38e,0x1c7},
{0x390,0x027},{0x391,0x227},{0x392,0x127},{0x393,0x327},{0x394,0x0a7},{0x395,0x2a7},{0x396,0x1a7},{0x398,0x067},
{0x399,0x267},{0x39a,0x167},{0x39b,0x367},{0x39c,0x0e7},{0x39d,0x2e7},{0x39e,0x1e7},{0x3a0,0x017},{0x3a1,0x217},
{0x3a2,0x117},{0x3a3,0x317},{0x3a4,0x097},{0x3a5,0x297},{0x3a6,0x197},{0x3a7,0x397},{0x3a8,0x057},{0x3a9,0x257},
{0x3aa,0x157},{0x3ab,0x357},{0x3ac,0x0d7},{0x3ad,0x2d7},{0x3ae,0x1d7},{0x3b0,0x037},{0x3b1,0x237},{0x3b2,0x137},
{0x3b3,0x337},{0x3b4,0x0b7},{0x3b5,0x2b7},{0x3b6,0x1b7},{0x3b8,0x077},{0x3b9,0x277},{0x3ba,0x177},{0x3bb,0x377},
{0x3bc,0x0f7},{0x3bd,0x2f7},{0x3be,0x1f7},{0x3c0,0x00f},{0x3c1,0x20f},{0x3c2,0x10f},{0x3c3,0x30f},{0x3c4,0x08f},
{0x3c5,0x28f},{0x3c6,0x18f},{0x3c7,0x38f},{0x3c8,0x04f},{0x3c9,0x24f},{0x3ca,0x14f},{0x3cb,0x34f},{0x3cc,0x0cf},
{0x3cd,0x2cf},{0x3ce,0x1cf},{0x3d0,0x02f},{0x3d1,0x22f},{0x3d2,0x12f},{0x3d3,0x32f},{0x3d4,0x0af},{0x3d5,0x2af},
{0x3d6,0x1af},{0x3d7,0x3af},{0x3d8,0x06f},{0x3d9,0x26f},{0x3da,0x16f},{0x3db,0x36f},{0x3dc,0x0ef},{0x3dd,0x2ef},
{0x3de,0x1ef},{0x3e0,0x01f},{0x3e1,0x21f},{0x3e2,0x11f},{0x3e3,0x31f},{0x3e4,0x09f},{0x3e5,0x29f},{0x3e6,0x19f},
{0x3e7,0x39f},{0x3e8,0x05f},{0x3e9,0x25f},{0x3ea,0x15f},{0x3eb,0x35f},{0x3ec,0x0df},{0x3ed,0x2df},{0x3ee,0x1df},
{0x3ef,0x3df},{0x3f0,0x03f},{0x3f1,0x23f},{0x3f2,0x13f},{0x3f3,0x33f},{0x3f4,0x0bf},{0x3f5,0x2bf},{0x3f6,0x1bf},
{0x3f7,0x3bf},{0x3f8,0x07f},{0x3f9,0x27f},{0x3fa,0x17f},{0x3fb,0x37f},{0x3fc,0x0ff},{0x3fd,0x2ff},{0x3fe,0x1ff}
};
{
int i;
for (i = 0; i < sizeof k1k2tab / sizeof k1k2tab[0]; ++i)
{
k1 = k1k2tab[i].k1;
k2 = k1k2tab[i].k2;
a = fz[k1];
fz[k1] = fz[k2];
fz[k2] = a;
}
}
for (fi=fz,fn=fz+1024;fi<fn;fi+=4)
{
FLOAT f0,f1,f2,f3;
f1 = fi[0 ]-fi[1 ];
f0 = fi[0 ]+fi[1 ];
f3 = fi[2 ]-fi[3 ];
f2 = fi[2 ]+fi[3 ];
fi[2 ] = (f0-f2);
fi[0 ] = (f0+f2);
fi[3 ] = (f1-f3);
fi[1 ] = (f1+f3);
}
k=0;
do
{
FLOAT s1,c1;
k += 2;
k1 = 1 << k;
k2 = k1 << 1;
k4 = k2 << 1;
k3 = k2 + k1;
kx = k1 >> 1;
fi = fz;
gi = fi + kx;
fn = fz + 1024;
do
{
FLOAT g0,f0,f1,g1,f2,g2,f3,g3;
f1 = fi[0 ] - fi[k1];
f0 = fi[0 ] + fi[k1];
f3 = fi[k2] - fi[k3];
f2 = fi[k2] + fi[k3];
fi[k2] = f0 - f2;
fi[0 ] = f0 + f2;
fi[k3] = f1 - f3;
fi[k1] = f1 + f3;
g1 = gi[0 ] - gi[k1];
g0 = gi[0 ] + gi[k1];
g3 = SQRT2 * gi[k3];
g2 = SQRT2 * gi[k2];
gi[k2] = g0 - g2;
gi[0 ] = g0 + g2;
gi[k3] = g1 - g3;
gi[k1] = g1 + g3;
gi += k4;
fi += k4;
}
while (fi<fn);
t_c = costab[k];
t_s = sintab[k];
c1 = 1;
s1 = 0;
for (i=1;i<kx;i++)
{
FLOAT c2,s2;
FLOAT t = c1;
c1 = t*t_c - s1*t_s;
s1 = t*t_s + s1*t_c;
c2 = c1*c1 - s1*s1;
s2 = 2*(c1*s1);
fn = fz + 1024;
fi = fz +i;
gi = fz +k1-i;
do
{
FLOAT a,b,g0,f0,f1,g1,f2,g2,f3,g3;
b = s2*fi[k1] - c2*gi[k1];
a = c2*fi[k1] + s2*gi[k1];
f1 = fi[0 ] - a;
f0 = fi[0 ] + a;
g1 = gi[0 ] - b;
g0 = gi[0 ] + b;
b = s2*fi[k3] - c2*gi[k3];
a = c2*fi[k3] + s2*gi[k3];
f3 = fi[k2] - a;
f2 = fi[k2] + a;
g3 = gi[k2] - b;
g2 = gi[k2] + b;
b = s1*f2 - c1*g3;
a = c1*f2 + s1*g3;
fi[k2] = f0 - a;
fi[0 ] = f0 + a;
gi[k3] = g1 - b;
gi[k1] = g1 + b;
b = c1*g2 - s1*f3;
a = s1*g2 + c1*f3;
gi[k2] = g0 - a;
gi[0 ] = g0 + a;
fi[k3] = f1 - b;
fi[k1] = f1 + b;
gi += k4;
fi += k4;
}
while (fi<fn);
}
}
while (k4<1024);
}
void fft(FLOAT *x_real, FLOAT *x_imag, FLOAT *energy, FLOAT *phi, int N)
{
FLOAT a,b;
int i,j;
fht(x_real);
energy[0] = x_real[0] * x_real[0];
for (i=1,j=N-1;i<N/2;i++,j--)
{
a = x_real[i];
b = x_real[j];
energy[i]=(a*a + b*b)/2.0;
if (energy[i] < 0.0005)
{
energy[i] = 0.0005;
phi[i] = 0;
}
else /* OPTIMZE this. LAME does without these atan2 calls at all */
phi[i] = 0.7853981 + atan2 (-(double)a, (double)b);
}
energy[N/2] = x_real[N/2] * x_real[N/2];
phi[N/2] = atan2 (0.0, (double)x_real[N/2]);
for (i=1;i<N/2;i++)
{
energy[N/2+i] = energy[N/2-i];
phi [N/2+i] = -phi[N/2-i];
}
}
void fft2(FLOAT *x_real, FLOAT *energy, int N)
{
FLOAT a,b;
int i,j;
fht(x_real);
energy[0] = x_real[0] * x_real[0];
for (i=1,j=N-1;i<N/2;i++,j--)
{
a = x_real[i];
b = x_real[j];
energy[i]=(a*a + b*b)/2.0;
}
energy[N/2] = x_real[N/2] * x_real[N/2];
}
|
