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1 | /* |
2 | * Copyright (c) 2013-2014 Mozilla Corporation | |
3 | * | |
4 | * This file is part of FFmpeg. | |
5 | * | |
6 | * FFmpeg is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * FFmpeg is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with FFmpeg; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | */ | |
20 | ||
21 | /** | |
22 | * @file | |
23 | * Celt non-power of 2 iMDCT | |
24 | */ | |
25 | ||
26 | #include <float.h> | |
27 | #include <math.h> | |
28 | #include <stddef.h> | |
29 | ||
30 | #include "config.h" | |
31 | ||
32 | #include "libavutil/attributes.h" | |
33 | #include "libavutil/common.h" | |
34 | ||
35 | #include "avfft.h" | |
36 | #include "opus.h" | |
37 | #include "opus_imdct.h" | |
38 | ||
39 | // minimal iMDCT size to make SIMD opts easier | |
40 | #define CELT_MIN_IMDCT_SIZE 120 | |
41 | ||
42 | // complex c = a * b | |
43 | #define CMUL3(cre, cim, are, aim, bre, bim) \ | |
44 | do { \ | |
45 | cre = are * bre - aim * bim; \ | |
46 | cim = are * bim + aim * bre; \ | |
47 | } while (0) | |
48 | ||
49 | #define CMUL(c, a, b) CMUL3((c).re, (c).im, (a).re, (a).im, (b).re, (b).im) | |
50 | ||
51 | // complex c = a * b | |
52 | // d = a * conjugate(b) | |
53 | #define CMUL2(c, d, a, b) \ | |
54 | do { \ | |
55 | float are = (a).re; \ | |
56 | float aim = (a).im; \ | |
57 | float bre = (b).re; \ | |
58 | float bim = (b).im; \ | |
59 | float rr = are * bre; \ | |
60 | float ri = are * bim; \ | |
61 | float ir = aim * bre; \ | |
62 | float ii = aim * bim; \ | |
63 | (c).re = rr - ii; \ | |
64 | (c).im = ri + ir; \ | |
65 | (d).re = rr + ii; \ | |
66 | (d).im = -ri + ir; \ | |
67 | } while (0) | |
68 | ||
69 | av_cold void ff_celt_imdct_uninit(CeltIMDCTContext **ps) | |
70 | { | |
71 | CeltIMDCTContext *s = *ps; | |
72 | int i; | |
73 | ||
74 | if (!s) | |
75 | return; | |
76 | ||
77 | for (i = 0; i < FF_ARRAY_ELEMS(s->exptab); i++) | |
78 | av_freep(&s->exptab[i]); | |
79 | ||
80 | av_freep(&s->twiddle_exptab); | |
81 | ||
82 | av_freep(&s->tmp); | |
83 | ||
84 | av_freep(ps); | |
85 | } | |
86 | ||
87 | static void celt_imdct_half(CeltIMDCTContext *s, float *dst, const float *src, | |
88 | ptrdiff_t stride, float scale); | |
89 | ||
90 | av_cold int ff_celt_imdct_init(CeltIMDCTContext **ps, int N) | |
91 | { | |
92 | CeltIMDCTContext *s; | |
93 | int len2 = 15 * (1 << N); | |
94 | int len = 2 * len2; | |
95 | int i, j; | |
96 | ||
97 | if (len2 > CELT_MAX_FRAME_SIZE || len2 < CELT_MIN_IMDCT_SIZE) | |
98 | return AVERROR(EINVAL); | |
99 | ||
100 | s = av_mallocz(sizeof(*s)); | |
101 | if (!s) | |
102 | return AVERROR(ENOMEM); | |
103 | ||
104 | s->fft_n = N - 1; | |
105 | s->len4 = len2 / 2; | |
106 | s->len2 = len2; | |
107 | ||
108 | s->tmp = av_malloc(len * 2 * sizeof(*s->tmp)); | |
109 | if (!s->tmp) | |
110 | goto fail; | |
111 | ||
112 | s->twiddle_exptab = av_malloc(s->len4 * sizeof(*s->twiddle_exptab)); | |
113 | if (!s->twiddle_exptab) | |
114 | goto fail; | |
115 | ||
116 | for (i = 0; i < s->len4; i++) { | |
117 | s->twiddle_exptab[i].re = cos(2 * M_PI * (i + 0.125 + s->len4) / len); | |
118 | s->twiddle_exptab[i].im = sin(2 * M_PI * (i + 0.125 + s->len4) / len); | |
119 | } | |
120 | ||
121 | for (i = 0; i < FF_ARRAY_ELEMS(s->exptab); i++) { | |
122 | int N = 15 * (1 << i); | |
123 | s->exptab[i] = av_malloc(sizeof(*s->exptab[i]) * FFMAX(N, 19)); | |
124 | if (!s->exptab[i]) | |
125 | goto fail; | |
126 | ||
127 | for (j = 0; j < N; j++) { | |
128 | s->exptab[i][j].re = cos(2 * M_PI * j / N); | |
129 | s->exptab[i][j].im = sin(2 * M_PI * j / N); | |
130 | } | |
131 | } | |
132 | ||
133 | // wrap around to simplify fft15 | |
134 | for (j = 15; j < 19; j++) | |
135 | s->exptab[0][j] = s->exptab[0][j - 15]; | |
136 | ||
137 | s->imdct_half = celt_imdct_half; | |
138 | ||
139 | if (ARCH_AARCH64) | |
140 | ff_celt_imdct_init_aarch64(s); | |
141 | ||
142 | *ps = s; | |
143 | ||
144 | return 0; | |
145 | fail: | |
146 | ff_celt_imdct_uninit(&s); | |
147 | return AVERROR(ENOMEM); | |
148 | } | |
149 | ||
150 | static void fft5(FFTComplex *out, const FFTComplex *in, ptrdiff_t stride) | |
151 | { | |
152 | // [0] = exp(2 * i * pi / 5), [1] = exp(2 * i * pi * 2 / 5) | |
153 | static const FFTComplex fact[] = { { 0.30901699437494745, 0.95105651629515353 }, | |
154 | { -0.80901699437494734, 0.58778525229247325 } }; | |
155 | ||
156 | FFTComplex z[4][4]; | |
157 | ||
158 | CMUL2(z[0][0], z[0][3], in[1 * stride], fact[0]); | |
159 | CMUL2(z[0][1], z[0][2], in[1 * stride], fact[1]); | |
160 | CMUL2(z[1][0], z[1][3], in[2 * stride], fact[0]); | |
161 | CMUL2(z[1][1], z[1][2], in[2 * stride], fact[1]); | |
162 | CMUL2(z[2][0], z[2][3], in[3 * stride], fact[0]); | |
163 | CMUL2(z[2][1], z[2][2], in[3 * stride], fact[1]); | |
164 | CMUL2(z[3][0], z[3][3], in[4 * stride], fact[0]); | |
165 | CMUL2(z[3][1], z[3][2], in[4 * stride], fact[1]); | |
166 | ||
167 | out[0].re = in[0].re + in[stride].re + in[2 * stride].re + in[3 * stride].re + in[4 * stride].re; | |
168 | out[0].im = in[0].im + in[stride].im + in[2 * stride].im + in[3 * stride].im + in[4 * stride].im; | |
169 | ||
170 | out[1].re = in[0].re + z[0][0].re + z[1][1].re + z[2][2].re + z[3][3].re; | |
171 | out[1].im = in[0].im + z[0][0].im + z[1][1].im + z[2][2].im + z[3][3].im; | |
172 | ||
173 | out[2].re = in[0].re + z[0][1].re + z[1][3].re + z[2][0].re + z[3][2].re; | |
174 | out[2].im = in[0].im + z[0][1].im + z[1][3].im + z[2][0].im + z[3][2].im; | |
175 | ||
176 | out[3].re = in[0].re + z[0][2].re + z[1][0].re + z[2][3].re + z[3][1].re; | |
177 | out[3].im = in[0].im + z[0][2].im + z[1][0].im + z[2][3].im + z[3][1].im; | |
178 | ||
179 | out[4].re = in[0].re + z[0][3].re + z[1][2].re + z[2][1].re + z[3][0].re; | |
180 | out[4].im = in[0].im + z[0][3].im + z[1][2].im + z[2][1].im + z[3][0].im; | |
181 | } | |
182 | ||
183 | static void fft15(CeltIMDCTContext *s, FFTComplex *out, const FFTComplex *in, ptrdiff_t stride) | |
184 | { | |
185 | const FFTComplex *exptab = s->exptab[0]; | |
186 | FFTComplex tmp[5]; | |
187 | FFTComplex tmp1[5]; | |
188 | FFTComplex tmp2[5]; | |
189 | int k; | |
190 | ||
191 | fft5(tmp, in, stride * 3); | |
192 | fft5(tmp1, in + stride, stride * 3); | |
193 | fft5(tmp2, in + 2 * stride, stride * 3); | |
194 | ||
195 | for (k = 0; k < 5; k++) { | |
196 | FFTComplex t1, t2; | |
197 | ||
198 | CMUL(t1, tmp1[k], exptab[k]); | |
199 | CMUL(t2, tmp2[k], exptab[2 * k]); | |
200 | out[k].re = tmp[k].re + t1.re + t2.re; | |
201 | out[k].im = tmp[k].im + t1.im + t2.im; | |
202 | ||
203 | CMUL(t1, tmp1[k], exptab[k + 5]); | |
204 | CMUL(t2, tmp2[k], exptab[2 * (k + 5)]); | |
205 | out[k + 5].re = tmp[k].re + t1.re + t2.re; | |
206 | out[k + 5].im = tmp[k].im + t1.im + t2.im; | |
207 | ||
208 | CMUL(t1, tmp1[k], exptab[k + 10]); | |
209 | CMUL(t2, tmp2[k], exptab[2 * k + 5]); | |
210 | out[k + 10].re = tmp[k].re + t1.re + t2.re; | |
211 | out[k + 10].im = tmp[k].im + t1.im + t2.im; | |
212 | } | |
213 | } | |
214 | ||
215 | /* | |
216 | * FFT of the length 15 * (2^N) | |
217 | */ | |
218 | static void fft_calc(CeltIMDCTContext *s, FFTComplex *out, const FFTComplex *in, | |
219 | int N, ptrdiff_t stride) | |
220 | { | |
221 | if (N) { | |
222 | const FFTComplex *exptab = s->exptab[N]; | |
223 | const int len2 = 15 * (1 << (N - 1)); | |
224 | int k; | |
225 | ||
226 | fft_calc(s, out, in, N - 1, stride * 2); | |
227 | fft_calc(s, out + len2, in + stride, N - 1, stride * 2); | |
228 | ||
229 | for (k = 0; k < len2; k++) { | |
230 | FFTComplex t; | |
231 | ||
232 | CMUL(t, out[len2 + k], exptab[k]); | |
233 | ||
234 | out[len2 + k].re = out[k].re - t.re; | |
235 | out[len2 + k].im = out[k].im - t.im; | |
236 | ||
237 | out[k].re += t.re; | |
238 | out[k].im += t.im; | |
239 | } | |
240 | } else | |
241 | fft15(s, out, in, stride); | |
242 | } | |
243 | ||
244 | static void celt_imdct_half(CeltIMDCTContext *s, float *dst, const float *src, | |
245 | ptrdiff_t stride, float scale) | |
246 | { | |
247 | FFTComplex *z = (FFTComplex *)dst; | |
248 | const int len8 = s->len4 / 2; | |
249 | const float *in1 = src; | |
250 | const float *in2 = src + (s->len2 - 1) * stride; | |
251 | int i; | |
252 | ||
253 | for (i = 0; i < s->len4; i++) { | |
254 | FFTComplex tmp = { *in2, *in1 }; | |
255 | CMUL(s->tmp[i], tmp, s->twiddle_exptab[i]); | |
256 | in1 += 2 * stride; | |
257 | in2 -= 2 * stride; | |
258 | } | |
259 | ||
260 | fft_calc(s, z, s->tmp, s->fft_n, 1); | |
261 | ||
262 | for (i = 0; i < len8; i++) { | |
263 | float r0, i0, r1, i1; | |
264 | ||
265 | CMUL3(r0, i1, z[len8 - i - 1].im, z[len8 - i - 1].re, s->twiddle_exptab[len8 - i - 1].im, s->twiddle_exptab[len8 - i - 1].re); | |
266 | CMUL3(r1, i0, z[len8 + i].im, z[len8 + i].re, s->twiddle_exptab[len8 + i].im, s->twiddle_exptab[len8 + i].re); | |
267 | z[len8 - i - 1].re = scale * r0; | |
268 | z[len8 - i - 1].im = scale * i0; | |
269 | z[len8 + i].re = scale * r1; | |
270 | z[len8 + i].im = scale * i1; | |
271 | } | |
272 | } |