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fft.h
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1 /*
2  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
3  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
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 #ifndef AVCODEC_FFT_H
23 #define AVCODEC_FFT_H
24 
25 #ifndef CONFIG_FFT_FLOAT
26 #define CONFIG_FFT_FLOAT 1
27 #endif
28 
29 #include <stdint.h>
30 #include "config.h"
31 #include "libavutil/mem.h"
32 
33 #if CONFIG_FFT_FLOAT
34 
35 #include "avfft.h"
36 
37 #define FFT_NAME(x) x
38 
39 typedef float FFTDouble;
40 
41 #else
42 
43 #define FFT_NAME(x) x ## _fixed
44 
45 typedef int16_t FFTSample;
46 typedef int FFTDouble;
47 
48 typedef struct FFTComplex {
49  int16_t re, im;
50 } FFTComplex;
51 
52 typedef struct FFTContext FFTContext;
53 
54 #endif /* CONFIG_FFT_FLOAT */
55 
56 typedef struct FFTDComplex {
58 } FFTDComplex;
59 
60 /* FFT computation */
61 
62 struct FFTContext {
63  int nbits;
64  int inverse;
65  uint16_t *revtab;
67  int mdct_size; /* size of MDCT (i.e. number of input data * 2) */
68  int mdct_bits; /* n = 2^nbits */
69  /* pre/post rotation tables */
72  /**
73  * Do the permutation needed BEFORE calling fft_calc().
74  */
76  /**
77  * Do a complex FFT with the parameters defined in ff_fft_init(). The
78  * input data must be permuted before. No 1.0/sqrt(n) normalization is done.
79  */
80  void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
81  void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
82  void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
83  void (*mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
84  void (*mdct_calcw)(struct FFTContext *s, FFTDouble *output, const FFTSample *input);
86 #define FF_FFT_PERM_DEFAULT 0
87 #define FF_FFT_PERM_SWAP_LSBS 1
88 #define FF_FFT_PERM_AVX 2
90 #define FF_MDCT_PERM_NONE 0
91 #define FF_MDCT_PERM_INTERLEAVE 1
92 };
93 
94 #if CONFIG_HARDCODED_TABLES
95 #define COSTABLE_CONST const
96 #else
97 #define COSTABLE_CONST
98 #endif
99 
100 #define COSTABLE(size) \
101  COSTABLE_CONST DECLARE_ALIGNED(32, FFTSample, FFT_NAME(ff_cos_##size))[size/2]
102 
103 extern COSTABLE(16);
104 extern COSTABLE(32);
105 extern COSTABLE(64);
106 extern COSTABLE(128);
107 extern COSTABLE(256);
108 extern COSTABLE(512);
109 extern COSTABLE(1024);
110 extern COSTABLE(2048);
111 extern COSTABLE(4096);
112 extern COSTABLE(8192);
113 extern COSTABLE(16384);
114 extern COSTABLE(32768);
115 extern COSTABLE(65536);
116 extern COSTABLE_CONST FFTSample* const FFT_NAME(ff_cos_tabs)[17];
117 
118 #define ff_init_ff_cos_tabs FFT_NAME(ff_init_ff_cos_tabs)
119 
120 /**
121  * Initialize the cosine table in ff_cos_tabs[index]
122  * @param index index in ff_cos_tabs array of the table to initialize
123  */
124 void ff_init_ff_cos_tabs(int index);
125 
126 #define ff_fft_init FFT_NAME(ff_fft_init)
127 #define ff_fft_end FFT_NAME(ff_fft_end)
128 
129 /**
130  * Set up a complex FFT.
131  * @param nbits log2 of the length of the input array
132  * @param inverse if 0 perform the forward transform, if 1 perform the inverse
133  */
134 int ff_fft_init(FFTContext *s, int nbits, int inverse);
135 
140 
142 
143 void ff_fft_end(FFTContext *s);
144 
145 #define ff_mdct_init FFT_NAME(ff_mdct_init)
146 #define ff_mdct_end FFT_NAME(ff_mdct_end)
147 
148 int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale);
149 void ff_mdct_end(FFTContext *s);
150 
151 #endif /* AVCODEC_FFT_H */