dct/fft: Give consistent names to fixed/float template files
[libav.git] / libavcodec / mdct_template.c
1 /*
2 * MDCT/IMDCT transforms
3 * Copyright (c) 2002 Fabrice Bellard
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 #include "fft-internal.h"
28
29 /**
30 * @file
31 * MDCT/IMDCT transforms.
32 */
33
34 #if CONFIG_FFT_FLOAT
35 # define RSCALE(x) (x)
36 #else
37 # define RSCALE(x) ((x) >> 1)
38 #endif
39
40 /**
41 * init MDCT or IMDCT computation.
42 */
43 av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
44 {
45 int n, n4, i;
46 double alpha, theta;
47 int tstep;
48
49 memset(s, 0, sizeof(*s));
50 n = 1 << nbits;
51 s->mdct_bits = nbits;
52 s->mdct_size = n;
53 n4 = n >> 2;
54 s->mdct_permutation = FF_MDCT_PERM_NONE;
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));
60 if (!s->tcos)
61 goto fail;
62
63 switch (s->mdct_permutation) {
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:
73 goto fail;
74 }
75
76 theta = 1.0 / 8.0 + (scale < 0 ? n4 : 0);
77 scale = sqrt(fabs(scale));
78 for(i=0;i<n4;i++) {
79 alpha = 2 * M_PI * (i + theta) / n;
80 s->tcos[i*tstep] = FIX15(-cos(alpha) * scale);
81 s->tsin[i*tstep] = FIX15(-sin(alpha) * scale);
82 }
83 return 0;
84 fail:
85 ff_mdct_end(s);
86 return -1;
87 }
88
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 */
95 void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input)
96 {
97 int k, n8, n4, n2, n, j;
98 const uint16_t *revtab = s->revtab;
99 const FFTSample *tcos = s->tcos;
100 const FFTSample *tsin = s->tsin;
101 const FFTSample *in1, *in2;
102 FFTComplex *z = (FFTComplex *)output;
103
104 n = 1 << s->mdct_bits;
105 n2 = n >> 1;
106 n4 = n >> 2;
107 n8 = n >> 3;
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 }
118 s->fft_calc(s, z);
119
120 /* post rotation + reordering */
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;
129 }
130 }
131
132 /**
133 * Compute inverse MDCT of size N = 2^nbits
134 * @param output N samples
135 * @param input N/2 samples
136 */
137 void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input)
138 {
139 int k;
140 int n = 1 << s->mdct_bits;
141 int n2 = n >> 1;
142 int n4 = n >> 2;
143
144 ff_imdct_half_c(s, output+n4, input);
145
146 for(k = 0; k < n4; k++) {
147 output[k] = -output[n2-k-1];
148 output[n-k-1] = output[n2+k];
149 }
150 }
151
152 /**
153 * Compute MDCT of size N = 2^nbits
154 * @param input N samples
155 * @param out N/2 samples
156 */
157 void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input)
158 {
159 int i, j, n, n8, n4, n2, n3;
160 FFTDouble re, im;
161 const uint16_t *revtab = s->revtab;
162 const FFTSample *tcos = s->tcos;
163 const FFTSample *tsin = s->tsin;
164 FFTComplex *x = (FFTComplex *)out;
165
166 n = 1 << s->mdct_bits;
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++) {
174 re = RSCALE(-input[2*i+n3] - input[n3-1-2*i]);
175 im = RSCALE(-input[n4+2*i] + input[n4-1-2*i]);
176 j = revtab[i];
177 CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
178
179 re = RSCALE( input[2*i] - input[n2-1-2*i]);
180 im = RSCALE(-input[n2+2*i] - input[ n-1-2*i]);
181 j = revtab[n8 + i];
182 CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
183 }
184
185 s->fft_calc(s, x);
186
187 /* post rotation */
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;
196 }
197 }
198
199 av_cold void ff_mdct_end(FFTContext *s)
200 {
201 av_freep(&s->tcos);
202 ff_fft_end(s);
203 }