Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / opus_imdct.c
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 }