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Diffstat (limited to 'lib/rbcodec/codecs/libwmavoice/mdct.c')
-rw-r--r-- | lib/rbcodec/codecs/libwmavoice/mdct.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libwmavoice/mdct.c b/lib/rbcodec/codecs/libwmavoice/mdct.c new file mode 100644 index 0000000000..58bff3517b --- /dev/null +++ b/lib/rbcodec/codecs/libwmavoice/mdct.c | |||
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1 | /* | ||
2 | * MDCT/IMDCT transforms | ||
3 | * Copyright (c) 2002 Fabrice Bellard | ||
4 | * | ||
5 | * This file is part of FFmpeg. | ||
6 | * | ||
7 | * FFmpeg is free software; you can redistribute it and/or | ||
8 | * modify it under the terms of the GNU Lesser General Public | ||
9 | * License as published by the Free Software Foundation; either | ||
10 | * version 2.1 of the License, or (at your option) any later version. | ||
11 | * | ||
12 | * FFmpeg is distributed in the hope that it will be useful, | ||
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
15 | * Lesser General Public License for more details. | ||
16 | * | ||
17 | * You should have received a copy of the GNU Lesser General Public | ||
18 | * License along with FFmpeg; if not, write to the Free Software | ||
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
20 | */ | ||
21 | |||
22 | #include <stdlib.h> | ||
23 | #include <string.h> | ||
24 | #include "libavutil/common.h" | ||
25 | #include "libavutil/mathematics.h" | ||
26 | #include "fft.h" | ||
27 | |||
28 | /** | ||
29 | * @file | ||
30 | * MDCT/IMDCT transforms. | ||
31 | */ | ||
32 | |||
33 | // Generate a Kaiser-Bessel Derived Window. | ||
34 | #define BESSEL_I0_ITER 50 // default: 50 iterations of Bessel I0 approximation | ||
35 | av_cold void ff_kbd_window_init(float *window, float alpha, int n) | ||
36 | { | ||
37 | int i, j; | ||
38 | double sum = 0.0, bessel, tmp; | ||
39 | double local_window[FF_KBD_WINDOW_MAX]; | ||
40 | double alpha2 = (alpha * M_PI / n) * (alpha * M_PI / n); | ||
41 | |||
42 | //assert(n <= FF_KBD_WINDOW_MAX); | ||
43 | |||
44 | for (i = 0; i < n; i++) { | ||
45 | tmp = i * (n - i) * alpha2; | ||
46 | bessel = 1.0; | ||
47 | for (j = BESSEL_I0_ITER; j > 0; j--) | ||
48 | bessel = bessel * tmp / (j * j) + 1; | ||
49 | sum += bessel; | ||
50 | local_window[i] = sum; | ||
51 | } | ||
52 | |||
53 | sum++; | ||
54 | for (i = 0; i < n; i++) | ||
55 | window[i] = sqrt(local_window[i] / sum); | ||
56 | } | ||
57 | |||
58 | #include "mdct_tablegen.h" | ||
59 | |||
60 | /** | ||
61 | * init MDCT or IMDCT computation. | ||
62 | */ | ||
63 | av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale) | ||
64 | { | ||
65 | int n, n4, i; | ||
66 | double alpha, theta; | ||
67 | int tstep; | ||
68 | |||
69 | memset(s, 0, sizeof(*s)); | ||
70 | n = 1 << nbits; | ||
71 | s->mdct_bits = nbits; | ||
72 | s->mdct_size = n; | ||
73 | n4 = n >> 2; | ||
74 | s->permutation = FF_MDCT_PERM_NONE; | ||
75 | |||
76 | if (ff_fft_init(s, s->mdct_bits - 2, inverse) < 0) | ||
77 | goto fail; | ||
78 | |||
79 | s->tcos = av_malloc(n/2 * sizeof(FFTSample)); | ||
80 | if (!s->tcos) | ||
81 | goto fail; | ||
82 | |||
83 | switch (s->permutation) { | ||
84 | case FF_MDCT_PERM_NONE: | ||
85 | s->tsin = s->tcos + n4; | ||
86 | tstep = 1; | ||
87 | break; | ||
88 | case FF_MDCT_PERM_INTERLEAVE: | ||
89 | s->tsin = s->tcos + 1; | ||
90 | tstep = 2; | ||
91 | break; | ||
92 | default: | ||
93 | goto fail; | ||
94 | } | ||
95 | |||
96 | theta = 1.0 / 8.0 + (scale < 0 ? n4 : 0); | ||
97 | scale = sqrt(fabs(scale)); | ||
98 | for(i=0;i<n4;i++) { | ||
99 | alpha = 2 * M_PI * (i + theta) / n; | ||
100 | s->tcos[i*tstep] = -cos(alpha) * scale; | ||
101 | s->tsin[i*tstep] = -sin(alpha) * scale; | ||
102 | } | ||
103 | return 0; | ||
104 | fail: | ||
105 | ff_mdct_end(s); | ||
106 | return -1; | ||
107 | } | ||
108 | |||
109 | /* complex multiplication: p = a * b */ | ||
110 | #define CMUL(pre, pim, are, aim, bre, bim) \ | ||
111 | {\ | ||
112 | FFTSample _are = (are);\ | ||
113 | FFTSample _aim = (aim);\ | ||
114 | FFTSample _bre = (bre);\ | ||
115 | FFTSample _bim = (bim);\ | ||
116 | (pre) = _are * _bre - _aim * _bim;\ | ||
117 | (pim) = _are * _bim + _aim * _bre;\ | ||
118 | } | ||
119 | |||
120 | /** | ||
121 | * Compute the middle half of the inverse MDCT of size N = 2^nbits, | ||
122 | * thus excluding the parts that can be derived by symmetry | ||
123 | * @param output N/2 samples | ||
124 | * @param input N/2 samples | ||
125 | */ | ||
126 | void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input) | ||
127 | { | ||
128 | int k, n8, n4, n2, n, j; | ||
129 | const uint16_t *revtab = s->revtab; | ||
130 | const FFTSample *tcos = s->tcos; | ||
131 | const FFTSample *tsin = s->tsin; | ||
132 | const FFTSample *in1, *in2; | ||
133 | FFTComplex *z = (FFTComplex *)output; | ||
134 | |||
135 | n = 1 << s->mdct_bits; | ||
136 | n2 = n >> 1; | ||
137 | n4 = n >> 2; | ||
138 | n8 = n >> 3; | ||
139 | |||
140 | /* pre rotation */ | ||
141 | in1 = input; | ||
142 | in2 = input + n2 - 1; | ||
143 | for(k = 0; k < n4; k++) { | ||
144 | j=revtab[k]; | ||
145 | CMUL(z[j].re, z[j].im, *in2, *in1, tcos[k], tsin[k]); | ||
146 | in1 += 2; | ||
147 | in2 -= 2; | ||
148 | } | ||
149 | ff_fft_calc(s, z); | ||
150 | |||
151 | /* post rotation + reordering */ | ||
152 | for(k = 0; k < n8; k++) { | ||
153 | FFTSample r0, i0, r1, i1; | ||
154 | CMUL(r0, i1, z[n8-k-1].im, z[n8-k-1].re, tsin[n8-k-1], tcos[n8-k-1]); | ||
155 | CMUL(r1, i0, z[n8+k ].im, z[n8+k ].re, tsin[n8+k ], tcos[n8+k ]); | ||
156 | z[n8-k-1].re = r0; | ||
157 | z[n8-k-1].im = i0; | ||
158 | z[n8+k ].re = r1; | ||
159 | z[n8+k ].im = i1; | ||
160 | } | ||
161 | } | ||
162 | |||
163 | /** | ||
164 | * Compute inverse MDCT of size N = 2^nbits | ||
165 | * @param output N samples | ||
166 | * @param input N/2 samples | ||
167 | */ | ||
168 | void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input) | ||
169 | { | ||
170 | int k; | ||
171 | int n = 1 << s->mdct_bits; | ||
172 | int n2 = n >> 1; | ||
173 | int n4 = n >> 2; | ||
174 | |||
175 | ff_imdct_half_c(s, output+n4, input); | ||
176 | |||
177 | for(k = 0; k < n4; k++) { | ||
178 | output[k] = -output[n2-k-1]; | ||
179 | output[n-k-1] = output[n2+k]; | ||
180 | } | ||
181 | } | ||
182 | |||
183 | /** | ||
184 | * Compute MDCT of size N = 2^nbits | ||
185 | * @param input N samples | ||
186 | * @param out N/2 samples | ||
187 | */ | ||
188 | void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input) | ||
189 | { | ||
190 | int i, j, n, n8, n4, n2, n3; | ||
191 | FFTSample re, im; | ||
192 | const uint16_t *revtab = s->revtab; | ||
193 | const FFTSample *tcos = s->tcos; | ||
194 | const FFTSample *tsin = s->tsin; | ||
195 | FFTComplex *x = (FFTComplex *)out; | ||
196 | |||
197 | n = 1 << s->mdct_bits; | ||
198 | n2 = n >> 1; | ||
199 | n4 = n >> 2; | ||
200 | n8 = n >> 3; | ||
201 | n3 = 3 * n4; | ||
202 | |||
203 | /* pre rotation */ | ||
204 | for(i=0;i<n8;i++) { | ||
205 | re = -input[2*i+3*n4] - input[n3-1-2*i]; | ||
206 | im = -input[n4+2*i] + input[n4-1-2*i]; | ||
207 | j = revtab[i]; | ||
208 | CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]); | ||
209 | |||
210 | re = input[2*i] - input[n2-1-2*i]; | ||
211 | im = -(input[n2+2*i] + input[n-1-2*i]); | ||
212 | j = revtab[n8 + i]; | ||
213 | CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]); | ||
214 | } | ||
215 | |||
216 | ff_fft_calc(s, x); | ||
217 | |||
218 | /* post rotation */ | ||
219 | for(i=0;i<n8;i++) { | ||
220 | FFTSample r0, i0, r1, i1; | ||
221 | CMUL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]); | ||
222 | CMUL(i0, r1, x[n8+i ].re, x[n8+i ].im, -tsin[n8+i ], -tcos[n8+i ]); | ||
223 | x[n8-i-1].re = r0; | ||
224 | x[n8-i-1].im = i0; | ||
225 | x[n8+i ].re = r1; | ||
226 | x[n8+i ].im = i1; | ||
227 | } | ||
228 | } | ||
229 | |||
230 | av_cold void ff_mdct_end(FFTContext *s) | ||
231 | { | ||
232 | av_freep(&s->tcos); | ||
233 | ff_fft_end(s); | ||
234 | } | ||