dct/fft: Give consistent names to fixed/float template files
[libav.git] / libavcodec / mdct_template.c
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1/*
2 * MDCT/IMDCT transforms
406792e7 3 * Copyright (c) 2002 Fabrice Bellard
bb6f5690 4 *
2912e87a 5 * This file is part of Libav.
b78e7197 6 *
2912e87a 7 * Libav is free software; you can redistribute it and/or
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8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
b78e7197 10 * version 2.1 of the License, or (at your option) any later version.
bb6f5690 11 *
2912e87a 12 * Libav is distributed in the hope that it will be useful,
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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
2912e87a 18 * License along with Libav; if not, write to the Free Software
5509bffa 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
bb6f5690 20 */
1429224b 21
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22#include <stdlib.h>
23#include <string.h>
24#include "libavutil/common.h"
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25#include "libavutil/mathematics.h"
26#include "fft.h"
7087ce08 27#include "fft-internal.h"
bb6f5690 28
983e3246 29/**
ba87f080 30 * @file
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31 * MDCT/IMDCT transforms.
32 */
33
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34#if CONFIG_FFT_FLOAT
35# define RSCALE(x) (x)
36#else
37# define RSCALE(x) ((x) >> 1)
38#endif
39
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40/**
41 * init MDCT or IMDCT computation.
bb6f5690 42 */
01b22147 43av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
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44{
45 int n, n4, i;
7d485f16 46 double alpha, theta;
94274b82 47 int tstep;
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48
49 memset(s, 0, sizeof(*s));
50 n = 1 << nbits;
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51 s->mdct_bits = nbits;
52 s->mdct_size = n;
bb6f5690 53 n4 = n >> 2;
e6b1ed69 54 s->mdct_permutation = FF_MDCT_PERM_NONE;
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55
56 if (ff_fft_init(s, s->mdct_bits - 2, inverse) < 0)
57 goto fail;
58
59 s->tcos = av_malloc(n/2 * sizeof(FFTSample));
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60 if (!s->tcos)
61 goto fail;
94274b82 62
e6b1ed69 63 switch (s->mdct_permutation) {
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64 case FF_MDCT_PERM_NONE:
65 s->tsin = s->tcos + n4;
66 tstep = 1;
67 break;
68 case FF_MDCT_PERM_INTERLEAVE:
69 s->tsin = s->tcos + 1;
70 tstep = 2;
71 break;
72 default:
bb6f5690 73 goto fail;
94274b82 74 }
bb6f5690 75
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76 theta = 1.0 / 8.0 + (scale < 0 ? n4 : 0);
77 scale = sqrt(fabs(scale));
bb6f5690 78 for(i=0;i<n4;i++) {
7d485f16 79 alpha = 2 * M_PI * (i + theta) / n;
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80 s->tcos[i*tstep] = FIX15(-cos(alpha) * scale);
81 s->tsin[i*tstep] = FIX15(-sin(alpha) * scale);
bb6f5690 82 }
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83 return 0;
84 fail:
94274b82 85 ff_mdct_end(s);
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86 return -1;
87}
88
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89/**
90 * Compute the middle half of the inverse MDCT of size N = 2^nbits,
91 * thus excluding the parts that can be derived by symmetry
92 * @param output N/2 samples
93 * @param input N/2 samples
94 */
01b22147 95void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input)
bb6f5690 96{
46803f4f 97 int k, n8, n4, n2, n, j;
01b22147 98 const uint16_t *revtab = s->revtab;
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99 const FFTSample *tcos = s->tcos;
100 const FFTSample *tsin = s->tsin;
101 const FFTSample *in1, *in2;
46803f4f 102 FFTComplex *z = (FFTComplex *)output;
bb6f5690 103
01b22147 104 n = 1 << s->mdct_bits;
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105 n2 = n >> 1;
106 n4 = n >> 2;
46803f4f 107 n8 = n >> 3;
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108
109 /* pre rotation */
110 in1 = input;
111 in2 = input + n2 - 1;
112 for(k = 0; k < n4; k++) {
113 j=revtab[k];
114 CMUL(z[j].re, z[j].im, *in2, *in1, tcos[k], tsin[k]);
115 in1 += 2;
116 in2 -= 2;
117 }
26f548bb 118 s->fft_calc(s, z);
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119
120 /* post rotation + reordering */
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121 for(k = 0; k < n8; k++) {
122 FFTSample r0, i0, r1, i1;
123 CMUL(r0, i1, z[n8-k-1].im, z[n8-k-1].re, tsin[n8-k-1], tcos[n8-k-1]);
124 CMUL(r1, i0, z[n8+k ].im, z[n8+k ].re, tsin[n8+k ], tcos[n8+k ]);
125 z[n8-k-1].re = r0;
126 z[n8-k-1].im = i0;
127 z[n8+k ].re = r1;
128 z[n8+k ].im = i1;
bb6f5690 129 }
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130}
131
132/**
133 * Compute inverse MDCT of size N = 2^nbits
134 * @param output N samples
135 * @param input N/2 samples
b9fa3208 136 */
01b22147 137void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input)
b9fa3208 138{
46803f4f 139 int k;
01b22147 140 int n = 1 << s->mdct_bits;
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141 int n2 = n >> 1;
142 int n4 = n >> 2;
bb6f5690 143
d46ac5bf 144 ff_imdct_half_c(s, output+n4, input);
bb6f5690 145
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146 for(k = 0; k < n4; k++) {
147 output[k] = -output[n2-k-1];
148 output[n-k-1] = output[n2+k];
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149 }
150}
151
152/**
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153 * Compute MDCT of size N = 2^nbits
154 * @param input N samples
155 * @param out N/2 samples
bb6f5690 156 */
01b22147 157void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input)
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158{
159 int i, j, n, n8, n4, n2, n3;
7087ce08 160 FFTDouble re, im;
01b22147 161 const uint16_t *revtab = s->revtab;
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162 const FFTSample *tcos = s->tcos;
163 const FFTSample *tsin = s->tsin;
46803f4f 164 FFTComplex *x = (FFTComplex *)out;
bb6f5690 165
01b22147 166 n = 1 << s->mdct_bits;
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167 n2 = n >> 1;
168 n4 = n >> 2;
169 n8 = n >> 3;
170 n3 = 3 * n4;
171
172 /* pre rotation */
173 for(i=0;i<n8;i++) {
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174 re = RSCALE(-input[2*i+n3] - input[n3-1-2*i]);
175 im = RSCALE(-input[n4+2*i] + input[n4-1-2*i]);
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176 j = revtab[i];
177 CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
178
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179 re = RSCALE( input[2*i] - input[n2-1-2*i]);
180 im = RSCALE(-input[n2+2*i] - input[ n-1-2*i]);
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181 j = revtab[n8 + i];
182 CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
183 }
184
26f548bb 185 s->fft_calc(s, x);
115329f1 186
bb6f5690 187 /* post rotation */
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188 for(i=0;i<n8;i++) {
189 FFTSample r0, i0, r1, i1;
190 CMUL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]);
191 CMUL(i0, r1, x[n8+i ].re, x[n8+i ].im, -tsin[n8+i ], -tcos[n8+i ]);
192 x[n8-i-1].re = r0;
193 x[n8-i-1].im = i0;
194 x[n8+i ].re = r1;
195 x[n8+i ].im = i1;
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196 }
197}
198
01b22147 199av_cold void ff_mdct_end(FFTContext *s)
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200{
201 av_freep(&s->tcos);
01b22147 202 ff_fft_end(s);
bb6f5690 203}