2 * Copyright (c) 2019 Lynne <dev@lynne.ee>
4 * Copyright (c) 2008 Loren Merritt
5 * Copyright (c) 2002 Fabrice Bellard
6 * Partly based on libdjbfft by D. J. Bernstein
8 * This file is part of FFmpeg.
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 /* All costabs for a type are defined here */
40 DECLARE_ALIGNED(32, FFTComplex, TX_NAME(ff_cos_53))[4];
42 static FFTSample * const cos_tabs[18] = {
57 TX_NAME(ff_cos_16384),
58 TX_NAME(ff_cos_32768),
59 TX_NAME(ff_cos_65536),
60 TX_NAME(ff_cos_131072),
63 static av_always_inline void init_cos_tabs_idx(int index)
66 double freq = 2*M_PI/m;
67 FFTSample *tab = cos_tabs[index];
68 for(int i = 0; i <= m/4; i++)
69 tab[i] = RESCALE(cos(i*freq));
70 for(int i = 1; i < m/4; i++)
71 tab[m/2 - i] = tab[i];
74 #define INIT_FF_COS_TABS_FUNC(index, size) \
75 static av_cold void init_cos_tabs_ ## size (void) \
77 init_cos_tabs_idx(index); \
80 INIT_FF_COS_TABS_FUNC(4, 16)
81 INIT_FF_COS_TABS_FUNC(5, 32)
82 INIT_FF_COS_TABS_FUNC(6, 64)
83 INIT_FF_COS_TABS_FUNC(7, 128)
84 INIT_FF_COS_TABS_FUNC(8, 256)
85 INIT_FF_COS_TABS_FUNC(9, 512)
86 INIT_FF_COS_TABS_FUNC(10, 1024)
87 INIT_FF_COS_TABS_FUNC(11, 2048)
88 INIT_FF_COS_TABS_FUNC(12, 4096)
89 INIT_FF_COS_TABS_FUNC(13, 8192)
90 INIT_FF_COS_TABS_FUNC(14, 16384)
91 INIT_FF_COS_TABS_FUNC(15, 32768)
92 INIT_FF_COS_TABS_FUNC(16, 65536)
93 INIT_FF_COS_TABS_FUNC(17, 131072)
95 static av_cold void ff_init_53_tabs(void)
97 TX_NAME(ff_cos_53)[0] = (FFTComplex){ RESCALE(cos(2 * M_PI / 12)), RESCALE(cos(2 * M_PI / 12)) };
98 TX_NAME(ff_cos_53)[1] = (FFTComplex){ RESCALE(cos(2 * M_PI / 6)), RESCALE(cos(2 * M_PI / 6)) };
99 TX_NAME(ff_cos_53)[2] = (FFTComplex){ RESCALE(cos(2 * M_PI / 5)), RESCALE(sin(2 * M_PI / 5)) };
100 TX_NAME(ff_cos_53)[3] = (FFTComplex){ RESCALE(cos(2 * M_PI / 10)), RESCALE(sin(2 * M_PI / 10)) };
103 static CosTabsInitOnce cos_tabs_init_once[] = {
104 { ff_init_53_tabs, AV_ONCE_INIT },
108 { init_cos_tabs_16, AV_ONCE_INIT },
109 { init_cos_tabs_32, AV_ONCE_INIT },
110 { init_cos_tabs_64, AV_ONCE_INIT },
111 { init_cos_tabs_128, AV_ONCE_INIT },
112 { init_cos_tabs_256, AV_ONCE_INIT },
113 { init_cos_tabs_512, AV_ONCE_INIT },
114 { init_cos_tabs_1024, AV_ONCE_INIT },
115 { init_cos_tabs_2048, AV_ONCE_INIT },
116 { init_cos_tabs_4096, AV_ONCE_INIT },
117 { init_cos_tabs_8192, AV_ONCE_INIT },
118 { init_cos_tabs_16384, AV_ONCE_INIT },
119 { init_cos_tabs_32768, AV_ONCE_INIT },
120 { init_cos_tabs_65536, AV_ONCE_INIT },
121 { init_cos_tabs_131072, AV_ONCE_INIT },
124 static av_cold void init_cos_tabs(int index)
126 ff_thread_once(&cos_tabs_init_once[index].control,
127 cos_tabs_init_once[index].func);
130 static av_always_inline void fft3(FFTComplex *out, FFTComplex *in,
138 BF(tmp[0].re, tmp[1].im, in[1].im, in[2].im);
139 BF(tmp[0].im, tmp[1].re, in[1].re, in[2].re);
141 out[0*stride].re = in[0].re + tmp[1].re;
142 out[0*stride].im = in[0].im + tmp[1].im;
145 mtmp[0] = (int64_t)TX_NAME(ff_cos_53)[0].re * tmp[0].re;
146 mtmp[1] = (int64_t)TX_NAME(ff_cos_53)[0].im * tmp[0].im;
147 mtmp[2] = (int64_t)TX_NAME(ff_cos_53)[1].re * tmp[1].re;
148 mtmp[3] = (int64_t)TX_NAME(ff_cos_53)[1].re * tmp[1].im;
149 out[1*stride].re = in[0].re - (mtmp[2] + mtmp[0] + 0x40000000 >> 31);
150 out[1*stride].im = in[0].im - (mtmp[3] - mtmp[1] + 0x40000000 >> 31);
151 out[2*stride].re = in[0].re - (mtmp[2] - mtmp[0] + 0x40000000 >> 31);
152 out[2*stride].im = in[0].im - (mtmp[3] + mtmp[1] + 0x40000000 >> 31);
154 tmp[0].re = TX_NAME(ff_cos_53)[0].re * tmp[0].re;
155 tmp[0].im = TX_NAME(ff_cos_53)[0].im * tmp[0].im;
156 tmp[1].re = TX_NAME(ff_cos_53)[1].re * tmp[1].re;
157 tmp[1].im = TX_NAME(ff_cos_53)[1].re * tmp[1].im;
158 out[1*stride].re = in[0].re - tmp[1].re + tmp[0].re;
159 out[1*stride].im = in[0].im - tmp[1].im - tmp[0].im;
160 out[2*stride].re = in[0].re - tmp[1].re - tmp[0].re;
161 out[2*stride].im = in[0].im - tmp[1].im + tmp[0].im;
165 #define DECL_FFT5(NAME, D0, D1, D2, D3, D4) \
166 static av_always_inline void NAME(FFTComplex *out, FFTComplex *in, \
169 FFTComplex z0[4], t[6]; \
171 BF(t[1].im, t[0].re, in[1].re, in[4].re); \
172 BF(t[1].re, t[0].im, in[1].im, in[4].im); \
173 BF(t[3].im, t[2].re, in[2].re, in[3].re); \
174 BF(t[3].re, t[2].im, in[2].im, in[3].im); \
176 out[D0*stride].re = in[0].re + t[0].re + t[2].re; \
177 out[D0*stride].im = in[0].im + t[0].im + t[2].im; \
179 SMUL(t[4].re, t[0].re, TX_NAME(ff_cos_53)[2].re, TX_NAME(ff_cos_53)[3].re, t[2].re, t[0].re); \
180 SMUL(t[4].im, t[0].im, TX_NAME(ff_cos_53)[2].re, TX_NAME(ff_cos_53)[3].re, t[2].im, t[0].im); \
181 CMUL(t[5].re, t[1].re, TX_NAME(ff_cos_53)[2].im, TX_NAME(ff_cos_53)[3].im, t[3].re, t[1].re); \
182 CMUL(t[5].im, t[1].im, TX_NAME(ff_cos_53)[2].im, TX_NAME(ff_cos_53)[3].im, t[3].im, t[1].im); \
184 BF(z0[0].re, z0[3].re, t[0].re, t[1].re); \
185 BF(z0[0].im, z0[3].im, t[0].im, t[1].im); \
186 BF(z0[2].re, z0[1].re, t[4].re, t[5].re); \
187 BF(z0[2].im, z0[1].im, t[4].im, t[5].im); \
189 out[D1*stride].re = in[0].re + z0[3].re; \
190 out[D1*stride].im = in[0].im + z0[0].im; \
191 out[D2*stride].re = in[0].re + z0[2].re; \
192 out[D2*stride].im = in[0].im + z0[1].im; \
193 out[D3*stride].re = in[0].re + z0[1].re; \
194 out[D3*stride].im = in[0].im + z0[2].im; \
195 out[D4*stride].re = in[0].re + z0[0].re; \
196 out[D4*stride].im = in[0].im + z0[3].im; \
199 DECL_FFT5(fft5, 0, 1, 2, 3, 4)
200 DECL_FFT5(fft5_m1, 0, 6, 12, 3, 9)
201 DECL_FFT5(fft5_m2, 10, 1, 7, 13, 4)
202 DECL_FFT5(fft5_m3, 5, 11, 2, 8, 14)
204 static av_always_inline void fft15(FFTComplex *out, FFTComplex *in,
209 for (int i = 0; i < 5; i++)
210 fft3(tmp + i, in + i*3, 5);
212 fft5_m1(out, tmp + 0, stride);
213 fft5_m2(out, tmp + 5, stride);
214 fft5_m3(out, tmp + 10, stride);
217 #define BUTTERFLIES(a0,a1,a2,a3) {\
219 BF(a2.re, a0.re, a0.re, t5);\
220 BF(a3.im, a1.im, a1.im, t3);\
222 BF(a3.re, a1.re, a1.re, t4);\
223 BF(a2.im, a0.im, a0.im, t6);\
226 // force loading all the inputs before storing any.
227 // this is slightly slower for small data, but avoids store->load aliasing
228 // for addresses separated by large powers of 2.
229 #define BUTTERFLIES_BIG(a0,a1,a2,a3) {\
230 FFTSample r0=a0.re, i0=a0.im, r1=a1.re, i1=a1.im;\
232 BF(a2.re, a0.re, r0, t5);\
233 BF(a3.im, a1.im, i1, t3);\
235 BF(a3.re, a1.re, r1, t4);\
236 BF(a2.im, a0.im, i0, t6);\
239 #define TRANSFORM(a0,a1,a2,a3,wre,wim) {\
240 CMUL(t1, t2, a2.re, a2.im, wre, -wim);\
241 CMUL(t5, t6, a3.re, a3.im, wre, wim);\
242 BUTTERFLIES(a0,a1,a2,a3)\
245 #define TRANSFORM_ZERO(a0,a1,a2,a3) {\
250 BUTTERFLIES(a0,a1,a2,a3)\
253 /* z[0...8n-1], w[1...2n-1] */
255 static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\
257 FFTSample t1, t2, t3, t4, t5, t6;\
261 const FFTSample *wim = wre+o1;\
264 TRANSFORM_ZERO(z[0],z[o1],z[o2],z[o3]);\
265 TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
270 TRANSFORM(z[0],z[o1],z[o2],z[o3],wre[0],wim[0]);\
271 TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
277 #define BUTTERFLIES BUTTERFLIES_BIG
280 #define DECL_FFT(n,n2,n4)\
281 static void fft##n(FFTComplex *z)\
286 pass(z,TX_NAME(ff_cos_##n),n4/2);\
289 static void fft2(FFTComplex *z)
292 BF(tmp.re, z[0].re, z[0].re, z[1].re);
293 BF(tmp.im, z[0].im, z[0].im, z[1].im);
297 static void fft4(FFTComplex *z)
299 FFTSample t1, t2, t3, t4, t5, t6, t7, t8;
301 BF(t3, t1, z[0].re, z[1].re);
302 BF(t8, t6, z[3].re, z[2].re);
303 BF(z[2].re, z[0].re, t1, t6);
304 BF(t4, t2, z[0].im, z[1].im);
305 BF(t7, t5, z[2].im, z[3].im);
306 BF(z[3].im, z[1].im, t4, t8);
307 BF(z[3].re, z[1].re, t3, t7);
308 BF(z[2].im, z[0].im, t2, t5);
311 static void fft8(FFTComplex *z)
313 FFTSample t1, t2, t3, t4, t5, t6;
317 BF(t1, z[5].re, z[4].re, -z[5].re);
318 BF(t2, z[5].im, z[4].im, -z[5].im);
319 BF(t5, z[7].re, z[6].re, -z[7].re);
320 BF(t6, z[7].im, z[6].im, -z[7].im);
322 BUTTERFLIES(z[0],z[2],z[4],z[6]);
323 TRANSFORM(z[1],z[3],z[5],z[7],RESCALE(M_SQRT1_2),RESCALE(M_SQRT1_2));
326 static void fft16(FFTComplex *z)
328 FFTSample t1, t2, t3, t4, t5, t6;
329 FFTSample cos_16_1 = TX_NAME(ff_cos_16)[1];
330 FFTSample cos_16_3 = TX_NAME(ff_cos_16)[3];
336 TRANSFORM_ZERO(z[0],z[4],z[8],z[12]);
337 TRANSFORM(z[2],z[6],z[10],z[14],RESCALE(M_SQRT1_2),RESCALE(M_SQRT1_2));
338 TRANSFORM(z[1],z[5],z[9],z[13],cos_16_1,cos_16_3);
339 TRANSFORM(z[3],z[7],z[11],z[15],cos_16_3,cos_16_1);
346 DECL_FFT(512,256,128)
347 #define pass pass_big
348 DECL_FFT(1024,512,256)
349 DECL_FFT(2048,1024,512)
350 DECL_FFT(4096,2048,1024)
351 DECL_FFT(8192,4096,2048)
352 DECL_FFT(16384,8192,4096)
353 DECL_FFT(32768,16384,8192)
354 DECL_FFT(65536,32768,16384)
355 DECL_FFT(131072,65536,32768)
357 static void (* const fft_dispatch[])(FFTComplex*) = {
358 NULL, fft2, fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512,
359 fft1024, fft2048, fft4096, fft8192, fft16384, fft32768, fft65536, fft131072
362 #define DECL_COMP_FFT(N) \
363 static void compound_fft_##N##xM(AVTXContext *s, void *_out, \
364 void *_in, ptrdiff_t stride) \
366 const int m = s->m, *in_map = s->pfatab, *out_map = in_map + N*m; \
367 FFTComplex *in = _in; \
368 FFTComplex *out = _out; \
369 FFTComplex fft##N##in[N]; \
370 void (*fftp)(FFTComplex *z) = fft_dispatch[av_log2(m)]; \
372 for (int i = 0; i < m; i++) { \
373 for (int j = 0; j < N; j++) \
374 fft##N##in[j] = in[in_map[i*N + j]]; \
375 fft##N(s->tmp + s->revtab[i], fft##N##in, m); \
378 for (int i = 0; i < N; i++) \
379 fftp(s->tmp + m*i); \
381 for (int i = 0; i < N*m; i++) \
382 out[i] = s->tmp[out_map[i]]; \
389 static void monolithic_fft(AVTXContext *s, void *_out, void *_in,
392 FFTComplex *in = _in;
393 FFTComplex *out = _out;
394 int m = s->m, mb = av_log2(m);
396 if (s->flags & AV_TX_INPLACE) {
398 int src, dst, *inplace_idx = s->inplace_idx;
400 src = *inplace_idx++;
404 dst = s->revtab[src];
406 FFSWAP(FFTComplex, tmp, out[dst]);
407 dst = s->revtab[dst];
408 } while (dst != src); /* Can be > as well, but is less predictable */
410 } while ((src = *inplace_idx++));
412 for (int i = 0; i < m; i++)
413 out[i] = in[s->revtab[i]];
416 fft_dispatch[mb](out);
419 static void naive_fft(AVTXContext *s, void *_out, void *_in,
422 FFTComplex *in = _in;
423 FFTComplex *out = _out;
425 double phase = s->inv ? 2.0*M_PI/n : -2.0*M_PI/n;
427 for(int i = 0; i < n; i++) {
428 FFTComplex tmp = { 0 };
429 for(int j = 0; j < n; j++) {
430 const double factor = phase*i*j;
431 const FFTComplex mult = {
432 RESCALE(cos(factor)),
433 RESCALE(sin(factor)),
436 CMUL3(res, in[j], mult);
444 #define DECL_COMP_IMDCT(N) \
445 static void compound_imdct_##N##xM(AVTXContext *s, void *_dst, void *_src, \
448 FFTComplex fft##N##in[N]; \
449 FFTComplex *z = _dst, *exp = s->exptab; \
450 const int m = s->m, len8 = N*m >> 1; \
451 const int *in_map = s->pfatab, *out_map = in_map + N*m; \
452 const FFTSample *src = _src, *in1, *in2; \
453 void (*fftp)(FFTComplex *) = fft_dispatch[av_log2(m)]; \
455 stride /= sizeof(*src); /* To convert it from bytes */ \
457 in2 = src + ((N*m*2) - 1) * stride; \
459 for (int i = 0; i < m; i++) { \
460 for (int j = 0; j < N; j++) { \
461 const int k = in_map[i*N + j]; \
462 FFTComplex tmp = { in2[-k*stride], in1[k*stride] }; \
463 CMUL3(fft##N##in[j], tmp, exp[k >> 1]); \
465 fft##N(s->tmp + s->revtab[i], fft##N##in, m); \
468 for (int i = 0; i < N; i++) \
469 fftp(s->tmp + m*i); \
471 for (int i = 0; i < len8; i++) { \
472 const int i0 = len8 + i, i1 = len8 - i - 1; \
473 const int s0 = out_map[i0], s1 = out_map[i1]; \
474 FFTComplex src1 = { s->tmp[s1].im, s->tmp[s1].re }; \
475 FFTComplex src0 = { s->tmp[s0].im, s->tmp[s0].re }; \
477 CMUL(z[i1].re, z[i0].im, src1.re, src1.im, exp[i1].im, exp[i1].re); \
478 CMUL(z[i0].re, z[i1].im, src0.re, src0.im, exp[i0].im, exp[i0].re); \
486 #define DECL_COMP_MDCT(N) \
487 static void compound_mdct_##N##xM(AVTXContext *s, void *_dst, void *_src, \
490 FFTSample *src = _src, *dst = _dst; \
491 FFTComplex *exp = s->exptab, tmp, fft##N##in[N]; \
492 const int m = s->m, len4 = N*m, len3 = len4 * 3, len8 = len4 >> 1; \
493 const int *in_map = s->pfatab, *out_map = in_map + N*m; \
494 void (*fftp)(FFTComplex *) = fft_dispatch[av_log2(m)]; \
496 stride /= sizeof(*dst); \
498 for (int i = 0; i < m; i++) { /* Folding and pre-reindexing */ \
499 for (int j = 0; j < N; j++) { \
500 const int k = in_map[i*N + j]; \
502 tmp.re = FOLD(-src[ len4 + k], src[1*len4 - 1 - k]); \
503 tmp.im = FOLD(-src[ len3 + k], -src[1*len3 - 1 - k]); \
505 tmp.re = FOLD(-src[ len4 + k], -src[5*len4 - 1 - k]); \
506 tmp.im = FOLD( src[-len4 + k], -src[1*len3 - 1 - k]); \
508 CMUL(fft##N##in[j].im, fft##N##in[j].re, tmp.re, tmp.im, \
509 exp[k >> 1].re, exp[k >> 1].im); \
511 fft##N(s->tmp + s->revtab[i], fft##N##in, m); \
514 for (int i = 0; i < N; i++) \
515 fftp(s->tmp + m*i); \
517 for (int i = 0; i < len8; i++) { \
518 const int i0 = len8 + i, i1 = len8 - i - 1; \
519 const int s0 = out_map[i0], s1 = out_map[i1]; \
520 FFTComplex src1 = { s->tmp[s1].re, s->tmp[s1].im }; \
521 FFTComplex src0 = { s->tmp[s0].re, s->tmp[s0].im }; \
523 CMUL(dst[2*i1*stride + stride], dst[2*i0*stride], src0.re, src0.im, \
524 exp[i0].im, exp[i0].re); \
525 CMUL(dst[2*i0*stride + stride], dst[2*i1*stride], src1.re, src1.im, \
526 exp[i1].im, exp[i1].re); \
534 static void monolithic_imdct(AVTXContext *s, void *_dst, void *_src,
537 FFTComplex *z = _dst, *exp = s->exptab;
538 const int m = s->m, len8 = m >> 1;
539 const FFTSample *src = _src, *in1, *in2;
540 void (*fftp)(FFTComplex *) = fft_dispatch[av_log2(m)];
542 stride /= sizeof(*src);
544 in2 = src + ((m*2) - 1) * stride;
546 for (int i = 0; i < m; i++) {
547 FFTComplex tmp = { in2[-2*i*stride], in1[2*i*stride] };
548 CMUL3(z[s->revtab[i]], tmp, exp[i]);
553 for (int i = 0; i < len8; i++) {
554 const int i0 = len8 + i, i1 = len8 - i - 1;
555 FFTComplex src1 = { z[i1].im, z[i1].re };
556 FFTComplex src0 = { z[i0].im, z[i0].re };
558 CMUL(z[i1].re, z[i0].im, src1.re, src1.im, exp[i1].im, exp[i1].re);
559 CMUL(z[i0].re, z[i1].im, src0.re, src0.im, exp[i0].im, exp[i0].re);
563 static void monolithic_mdct(AVTXContext *s, void *_dst, void *_src,
566 FFTSample *src = _src, *dst = _dst;
567 FFTComplex *exp = s->exptab, tmp, *z = _dst;
568 const int m = s->m, len4 = m, len3 = len4 * 3, len8 = len4 >> 1;
569 void (*fftp)(FFTComplex *) = fft_dispatch[av_log2(m)];
571 stride /= sizeof(*dst);
573 for (int i = 0; i < m; i++) { /* Folding and pre-reindexing */
576 tmp.re = FOLD(-src[ len4 + k], src[1*len4 - 1 - k]);
577 tmp.im = FOLD(-src[ len3 + k], -src[1*len3 - 1 - k]);
579 tmp.re = FOLD(-src[ len4 + k], -src[5*len4 - 1 - k]);
580 tmp.im = FOLD( src[-len4 + k], -src[1*len3 - 1 - k]);
582 CMUL(z[s->revtab[i]].im, z[s->revtab[i]].re, tmp.re, tmp.im,
583 exp[i].re, exp[i].im);
588 for (int i = 0; i < len8; i++) {
589 const int i0 = len8 + i, i1 = len8 - i - 1;
590 FFTComplex src1 = { z[i1].re, z[i1].im };
591 FFTComplex src0 = { z[i0].re, z[i0].im };
593 CMUL(dst[2*i1*stride + stride], dst[2*i0*stride], src0.re, src0.im,
594 exp[i0].im, exp[i0].re);
595 CMUL(dst[2*i0*stride + stride], dst[2*i1*stride], src1.re, src1.im,
596 exp[i1].im, exp[i1].re);
600 static void naive_imdct(AVTXContext *s, void *_dst, void *_src,
605 FFTSample *src = _src;
606 FFTSample *dst = _dst;
607 double scale = s->scale;
608 const double phase = M_PI/(4.0*len2);
610 stride /= sizeof(*src);
612 for (int i = 0; i < len; i++) {
615 double i_d = phase * (4*len - 2*i - 1);
616 double i_u = phase * (3*len2 + 2*i + 1);
617 for (int j = 0; j < len2; j++) {
618 double a = (2 * j + 1);
619 double a_d = cos(a * i_d);
620 double a_u = cos(a * i_u);
621 double val = UNSCALE(src[j*stride]);
625 dst[i + 0] = RESCALE( sum_d*scale);
626 dst[i + len] = RESCALE(-sum_u*scale);
630 static void naive_mdct(AVTXContext *s, void *_dst, void *_src,
634 FFTSample *src = _src;
635 FFTSample *dst = _dst;
636 double scale = s->scale;
637 const double phase = M_PI/(4.0*len);
639 stride /= sizeof(*dst);
641 for (int i = 0; i < len; i++) {
643 for (int j = 0; j < len*2; j++) {
644 int a = (2*j + 1 + len) * (2*i + 1);
645 sum += UNSCALE(src[j]) * cos(a * phase);
647 dst[i*stride] = RESCALE(sum*scale);
651 static int gen_mdct_exptab(AVTXContext *s, int len4, double scale)
653 const double theta = (scale < 0 ? len4 : 0) + 1.0/8.0;
655 if (!(s->exptab = av_malloc_array(len4, sizeof(*s->exptab))))
656 return AVERROR(ENOMEM);
658 scale = sqrt(fabs(scale));
659 for (int i = 0; i < len4; i++) {
660 const double alpha = M_PI_2 * (i + theta) / len4;
661 s->exptab[i].re = RESCALE(cos(alpha) * scale);
662 s->exptab[i].im = RESCALE(sin(alpha) * scale);
668 int TX_NAME(ff_tx_init_mdct_fft)(AVTXContext *s, av_tx_fn *tx,
669 enum AVTXType type, int inv, int len,
670 const void *scale, uint64_t flags)
672 const int is_mdct = ff_tx_type_is_mdct(type);
673 int err, l, n = 1, m = 1, max_ptwo = 1 << (FF_ARRAY_ELEMS(fft_dispatch) - 1);
680 #define CHECK_FACTOR(DST, FACTOR, SRC) \
681 if (DST == 1 && !(SRC % FACTOR)) { \
685 CHECK_FACTOR(n, 15, len)
686 CHECK_FACTOR(n, 5, len)
687 CHECK_FACTOR(n, 3, len)
690 /* len must be a power of two now */
691 if (!(len & (len - 1)) && len >= 2 && len <= max_ptwo) {
702 /* If we weren't able to split the length into factors we can handle,
703 * resort to using the naive and slow FT. This also filters out
704 * direct 3, 5 and 15 transforms as they're too niche. */
705 if (len > 1 || m == 1) {
706 if (is_mdct && (l & 1)) /* Odd (i)MDCTs are not supported yet */
707 return AVERROR(ENOSYS);
708 if (flags & AV_TX_INPLACE) /* Neither are in-place naive transforms */
709 return AVERROR(ENOSYS);
714 s->scale = *((SCALE_TYPE *)scale);
715 *tx = inv ? naive_imdct : naive_mdct;
720 if (n > 1 && m > 1) { /* 2D transform case */
721 if ((err = ff_tx_gen_compound_mapping(s)))
723 if (!(s->tmp = av_malloc(n*m*sizeof(*s->tmp))))
724 return AVERROR(ENOMEM);
725 *tx = n == 3 ? compound_fft_3xM :
726 n == 5 ? compound_fft_5xM :
729 *tx = n == 3 ? inv ? compound_imdct_3xM : compound_mdct_3xM :
730 n == 5 ? inv ? compound_imdct_5xM : compound_mdct_5xM :
731 inv ? compound_imdct_15xM : compound_mdct_15xM;
732 } else { /* Direct transform case */
733 *tx = monolithic_fft;
735 *tx = inv ? monolithic_imdct : monolithic_mdct;
741 if ((err = ff_tx_gen_ptwo_revtab(s, n == 1 && !is_mdct && !(flags & AV_TX_INPLACE))))
743 if (flags & AV_TX_INPLACE) {
744 if (is_mdct) /* In-place MDCTs are not supported yet */
745 return AVERROR(ENOSYS);
746 if ((err = ff_tx_gen_ptwo_inplace_revtab_idx(s)))
749 for (int i = 4; i <= av_log2(m); i++)
754 return gen_mdct_exptab(s, n*m, *((SCALE_TYPE *)scale));