move sine window stuff from imdct.c to wmadec_filter.c.
[paraslash.git] / imdct.c
1 /*
2 * FFT/IFFT transforms.
3 *
4 * Extracted 2009 from mplayer 2009-02-10 libavcodec/fft.c and libavcodec/mdct.c
5 *
6 * Copyright (c) 2008 Loren Merritt
7 * Copyright (c) 2002 Fabrice Bellard
8 * Partly based on libdjbfft by D. J. Bernstein
9 *
10 * Licensed under the GNU Lesser General Public License.
11 * For licencing details see COPYING.LIB.
12 */
13
14 /**
15 * \file imdct.c Inverse modified discrete cosine transform.
16 */
17
18 #include <inttypes.h>
19 #include <math.h>
20 #include <string.h>
21 #include <stdlib.h>
22 #include <regex.h>
23
24 #include "para.h"
25 #include "error.h"
26 #include "string.h"
27 #include "imdct.h"
28 #include "wma.h"
29
30 typedef float fftsample_t;
31
32 #define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
33
34 struct fft_complex {
35 fftsample_t re, im;
36 };
37
38 struct fft_context {
39 int nbits;
40 int inverse;
41 uint16_t *revtab;
42 struct fft_complex *exptab;
43 };
44
45 struct mdct_context {
46 /** Size of MDCT (i.e. number of input data * 2). */
47 int n;
48 /** n = 2^n bits. */
49 int nbits;
50 /** pre/post rotation tables */
51 fftsample_t *tcos;
52 fftsample_t *tsin;
53 struct fft_context fft;
54 };
55
56 /* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */
57 DECLARE_ALIGNED_16(fftsample_t, ff_cos_16[8]);
58 DECLARE_ALIGNED_16(fftsample_t, ff_cos_32[16]);
59 DECLARE_ALIGNED_16(fftsample_t, ff_cos_64[32]);
60 DECLARE_ALIGNED_16(fftsample_t, ff_cos_128[64]);
61 DECLARE_ALIGNED_16(fftsample_t, ff_cos_256[128]);
62 DECLARE_ALIGNED_16(fftsample_t, ff_cos_512[256]);
63 DECLARE_ALIGNED_16(fftsample_t, ff_cos_1024[512]);
64 DECLARE_ALIGNED_16(fftsample_t, ff_cos_2048[1024]);
65 DECLARE_ALIGNED_16(fftsample_t, ff_cos_4096[2048]);
66 DECLARE_ALIGNED_16(fftsample_t, ff_cos_8192[4096]);
67 DECLARE_ALIGNED_16(fftsample_t, ff_cos_16384[8192]);
68 DECLARE_ALIGNED_16(fftsample_t, ff_cos_32768[16384]);
69 DECLARE_ALIGNED_16(fftsample_t, ff_cos_65536[32768]);
70
71 static fftsample_t *ff_cos_tabs[] = {
72 ff_cos_16, ff_cos_32, ff_cos_64, ff_cos_128, ff_cos_256,
73 ff_cos_512, ff_cos_1024, ff_cos_2048, ff_cos_4096, ff_cos_8192,
74 ff_cos_16384, ff_cos_32768, ff_cos_65536,
75 };
76
77 static int split_radix_permutation(int i, int n, int inverse)
78 {
79 int m;
80 if (n <= 2)
81 return i & 1;
82 m = n >> 1;
83 if (!(i & m))
84 return split_radix_permutation(i, m, inverse) * 2;
85 m >>= 1;
86 if (inverse == !(i & m))
87 return split_radix_permutation(i, m, inverse) * 4 + 1;
88 else
89 return split_radix_permutation(i, m, inverse) * 4 - 1;
90 }
91
92 #define sqrthalf (float)M_SQRT1_2
93
94 #define BF(x,y,a,b) {\
95 x = a - b;\
96 y = a + b;\
97 }
98
99 #define BUTTERFLIES(a0,a1,a2,a3) {\
100 BF(t3, t5, t5, t1);\
101 BF(a2.re, a0.re, a0.re, t5);\
102 BF(a3.im, a1.im, a1.im, t3);\
103 BF(t4, t6, t2, t6);\
104 BF(a3.re, a1.re, a1.re, t4);\
105 BF(a2.im, a0.im, a0.im, t6);\
106 }
107
108 // force loading all the inputs before storing any.
109 // this is slightly slower for small data, but avoids store->load aliasing
110 // for addresses separated by large powers of 2.
111 #define BUTTERFLIES_BIG(a0,a1,a2,a3) {\
112 fftsample_t r0=a0.re, i0=a0.im, r1=a1.re, i1=a1.im;\
113 BF(t3, t5, t5, t1);\
114 BF(a2.re, a0.re, r0, t5);\
115 BF(a3.im, a1.im, i1, t3);\
116 BF(t4, t6, t2, t6);\
117 BF(a3.re, a1.re, r1, t4);\
118 BF(a2.im, a0.im, i0, t6);\
119 }
120
121 #define TRANSFORM(a0,a1,a2,a3,wre,wim) {\
122 t1 = a2.re * wre + a2.im * wim;\
123 t2 = a2.im * wre - a2.re * wim;\
124 t5 = a3.re * wre - a3.im * wim;\
125 t6 = a3.im * wre + a3.re * wim;\
126 BUTTERFLIES(a0,a1,a2,a3)\
127 }
128
129 #define TRANSFORM_ZERO(a0,a1,a2,a3) {\
130 t1 = a2.re;\
131 t2 = a2.im;\
132 t5 = a3.re;\
133 t6 = a3.im;\
134 BUTTERFLIES(a0,a1,a2,a3)\
135 }
136
137 /* z[0...8n-1], w[1...2n-1] */
138 #define PASS(name)\
139 static void name(struct fft_complex *z, const fftsample_t *wre, unsigned int n)\
140 {\
141 fftsample_t t1, t2, t3, t4, t5, t6;\
142 int o1 = 2*n;\
143 int o2 = 4*n;\
144 int o3 = 6*n;\
145 const fftsample_t *wim = wre+o1;\
146 n--;\
147 \
148 TRANSFORM_ZERO(z[0],z[o1],z[o2],z[o3]);\
149 TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
150 do {\
151 z += 2;\
152 wre += 2;\
153 wim -= 2;\
154 TRANSFORM(z[0],z[o1],z[o2],z[o3],wre[0],wim[0]);\
155 TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
156 } while(--n);\
157 }
158
159 PASS(pass)
160 #undef BUTTERFLIES
161 #define BUTTERFLIES BUTTERFLIES_BIG
162
163 #define DECL_FFT(n,n2,n4)\
164 static void fft##n(struct fft_complex *z)\
165 {\
166 fft##n2(z);\
167 fft##n4(z+n4*2);\
168 fft##n4(z+n4*3);\
169 pass(z,ff_cos_##n,n4/2);\
170 }
171 static void fft4(struct fft_complex *z)
172 {
173 fftsample_t t1, t2, t3, t4, t5, t6, t7, t8;
174
175 BF(t3, t1, z[0].re, z[1].re);
176 BF(t8, t6, z[3].re, z[2].re);
177 BF(z[2].re, z[0].re, t1, t6);
178 BF(t4, t2, z[0].im, z[1].im);
179 BF(t7, t5, z[2].im, z[3].im);
180 BF(z[3].im, z[1].im, t4, t8);
181 BF(z[3].re, z[1].re, t3, t7);
182 BF(z[2].im, z[0].im, t2, t5);
183 }
184
185 static void fft8(struct fft_complex *z)
186 {
187 fftsample_t t1, t2, t3, t4, t5, t6, t7, t8;
188
189 fft4(z);
190
191 BF(t1, z[5].re, z[4].re, -z[5].re);
192 BF(t2, z[5].im, z[4].im, -z[5].im);
193 BF(t3, z[7].re, z[6].re, -z[7].re);
194 BF(t4, z[7].im, z[6].im, -z[7].im);
195 BF(t8, t1, t3, t1);
196 BF(t7, t2, t2, t4);
197 BF(z[4].re, z[0].re, z[0].re, t1);
198 BF(z[4].im, z[0].im, z[0].im, t2);
199 BF(z[6].re, z[2].re, z[2].re, t7);
200 BF(z[6].im, z[2].im, z[2].im, t8);
201
202 TRANSFORM(z[1], z[3], z[5], z[7], sqrthalf, sqrthalf);
203 }
204
205 static void fft16(struct fft_complex *z)
206 {
207 fftsample_t t1, t2, t3, t4, t5, t6;
208
209 fft8(z);
210 fft4(z + 8);
211 fft4(z + 12);
212
213 TRANSFORM_ZERO(z[0], z[4], z[8], z[12]);
214 TRANSFORM(z[2], z[6], z[10], z[14], sqrthalf, sqrthalf);
215 TRANSFORM(z[1], z[5], z[9], z[13], ff_cos_16[1], ff_cos_16[3]);
216 TRANSFORM(z[3], z[7], z[11], z[15], ff_cos_16[3], ff_cos_16[1]);
217 }
218
219 DECL_FFT(32, 16, 8)
220 DECL_FFT(64, 32, 16)
221 DECL_FFT(128, 64, 32)
222 DECL_FFT(256, 128, 64)
223 DECL_FFT(512, 256, 128)
224
225 DECL_FFT(1024, 512, 256)
226 DECL_FFT(2048, 1024, 512)
227 DECL_FFT(4096, 2048, 1024)
228 DECL_FFT(8192, 4096, 2048)
229 DECL_FFT(16384, 8192, 4096)
230 DECL_FFT(32768, 16384, 8192)
231 DECL_FFT(65536, 32768, 16384)
232
233 static void (*fft_dispatch[]) (struct fft_complex *) = {
234 fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024,
235 fft2048, fft4096, fft8192, fft16384, fft32768, fft65536,
236 };
237
238 static void fft(struct fft_context *s, struct fft_complex *z)
239 {
240 fft_dispatch[s->nbits - 2] (z);
241 }
242
243 /* complex multiplication: p = a * b */
244 #define CMUL(pre, pim, are, aim, bre, bim) \
245 {\
246 fftsample_t _are = (are);\
247 fftsample_t _aim = (aim);\
248 fftsample_t _bre = (bre);\
249 fftsample_t _bim = (bim);\
250 (pre) = _are * _bre - _aim * _bim;\
251 (pim) = _are * _bim + _aim * _bre;\
252 }
253
254 /**
255 * Compute the middle half of the inverse MDCT of size N = 2^nbits
256 *
257 * Thus excluding the parts that can be derived by symmetry.
258 *
259 * \param output N/2 samples.
260 * \param input N/2 samples.
261 */
262 static void imdct_half(struct mdct_context *s, fftsample_t *output,
263 const fftsample_t *input)
264 {
265 int k, n8, n4, n2, n, j;
266 const uint16_t *revtab = s->fft.revtab;
267 const fftsample_t *tcos = s->tcos;
268 const fftsample_t *tsin = s->tsin;
269 const fftsample_t *in1, *in2;
270 struct fft_complex *z = (struct fft_complex *)output;
271
272 n = 1 << s->nbits;
273 n2 = n >> 1;
274 n4 = n >> 2;
275 n8 = n >> 3;
276
277 /* pre rotation */
278 in1 = input;
279 in2 = input + n2 - 1;
280 for (k = 0; k < n4; k++) {
281 j = revtab[k];
282 CMUL(z[j].re, z[j].im, *in2, *in1, tcos[k], tsin[k]);
283 in1 += 2;
284 in2 -= 2;
285 }
286 fft(&s->fft, z);
287
288 /* post rotation + reordering */
289 output += n4;
290 for (k = 0; k < n8; k++) {
291 fftsample_t r0, i0, r1, i1;
292 CMUL(r0, i1, z[n8 - k - 1].im, z[n8 - k - 1].re,
293 tsin[n8 - k - 1], tcos[n8 - k - 1]);
294 CMUL(r1, i0, z[n8 + k].im, z[n8 + k].re, tsin[n8 + k],
295 tcos[n8 + k]);
296 z[n8 - k - 1].re = r0;
297 z[n8 - k - 1].im = i0;
298 z[n8 + k].re = r1;
299 z[n8 + k].im = i1;
300 }
301 }
302
303 /**
304 * Compute the inverse MDCT of size N = 2^nbits.
305 *
306 * \param output N samples.
307 * \param input N/2 samples.
308 */
309 void imdct(struct mdct_context *s, float *output, const float *input)
310 {
311 int k;
312 int n = 1 << s->nbits;
313 int n2 = n >> 1;
314 int n4 = n >> 2;
315
316 imdct_half(s, output + n4, input);
317
318 for (k = 0; k < n4; k++) {
319 output[k] = -output[n2 - k - 1];
320 output[n - k - 1] = output[n2 + k];
321 }
322 }
323
324 static int fft_init(struct fft_context *s, int nbits, int inverse)
325 {
326 int i, j, n;
327
328 if (nbits < 2 || nbits > 16)
329 return -E_FFT_BAD_PARAMS;
330 s->nbits = nbits;
331 n = 1 << nbits;
332
333 s->exptab = para_malloc((n / 2) * sizeof(struct fft_complex));
334 s->revtab = para_malloc(n * sizeof(uint16_t));
335 s->inverse = inverse;
336
337 for (j = 4; j <= nbits; j++) {
338 int k = 1 << j;
339 double freq = 2 * M_PI / k;
340 fftsample_t *tab = ff_cos_tabs[j - 4];
341 for (i = 0; i <= k / 4; i++)
342 tab[i] = cos(i * freq);
343 for (i = 1; i < k / 4; i++)
344 tab[k / 2 - i] = tab[i];
345 }
346 for (i = 0; i < n; i++)
347 s->revtab[-split_radix_permutation(
348 i, n, s->inverse) & (n - 1)] = i;
349 return 0;
350 }
351
352 static void fft_end(struct fft_context *ctx)
353 {
354 freep(&ctx->revtab);
355 freep(&ctx->exptab);
356 }
357
358 /**
359 * Init MDCT or IMDCT computation.
360 */
361 int imdct_init(int nbits, int inverse, struct mdct_context **result)
362 {
363 int ret, n, n4, i;
364 double alpha;
365 struct mdct_context *s;
366
367 s = para_calloc(sizeof(*s));
368 n = 1 << nbits;
369 s->nbits = nbits;
370 s->n = n;
371 n4 = n >> 2;
372 s->tcos = para_malloc(n4 * sizeof(fftsample_t));
373 s->tsin = para_malloc(n4 * sizeof(fftsample_t));
374
375 for (i = 0; i < n4; i++) {
376 alpha = 2 * M_PI * (i + 1.0 / 8.0) / n;
377 s->tcos[i] = -cos(alpha);
378 s->tsin[i] = -sin(alpha);
379 }
380 ret = fft_init(&s->fft, s->nbits - 2, inverse);
381 if (ret < 0)
382 goto fail;
383 *result = s;
384 return 0;
385 fail:
386 freep(&s->tcos);
387 freep(&s->tsin);
388 free(s);
389 return ret;
390 }
391
392 void imdct_end(struct mdct_context *ctx)
393 {
394 freep(&ctx->tcos);
395 freep(&ctx->tsin);
396 fft_end(&ctx->fft);
397 free(ctx);
398 }