FFmpeg: libavcodec/fft.h Source File

FFmpeg
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 FFT_FLOAT
26  #define FFT_FLOAT 1
27 #endif
28 
29 #ifndef FFT_FIXED_32
30  #define FFT_FIXED_32 0
31 #endif
32 
33 #include <stdint.h>
34 #include "config.h"
35 #include "libavutil/mem.h"
36 
37 #if FFT_FLOAT
38 
39 #include "avfft.h"
40 
41  #define FFT_NAME(x) x
42 
43  typedef float FFTDouble;
44 
45 #else
46 
47 #if FFT_FIXED_32
48 
49 #define Q31(x) (int)((x)*2147483648.0 + 0.5)
50 #define FFT_NAME(x) x ## _fixed_32
51 
52 typedef int32_t FFTSample;
53 
54 #else /* FFT_FIXED_32 */
55 
56 #define FFT_NAME(x) x ## _fixed
57 
58 typedef int16_t FFTSample;
59 
60 #endif /* FFT_FIXED_32 */
61 
62 typedef struct FFTComplex {
63  FFTSample re, im;
64 } FFTComplex;
65 
66 typedef int FFTDouble;
67 typedef struct FFTContext FFTContext;
68 
69 #endif /* FFT_FLOAT */
70 
71  typedef struct FFTDComplex {
72   FFTDouble re, im;
73 } FFTDComplex;
74 
75 /* FFT computation */
76 
77  enum fft_permutation_type {
78   FF_FFT_PERM_DEFAULT,
79   FF_FFT_PERM_SWAP_LSBS,
80   FF_FFT_PERM_AVX,
81 };
82 
83  enum mdct_permutation_type {
84   FF_MDCT_PERM_NONE,
85   FF_MDCT_PERM_INTERLEAVE,
86 };
87 
88  struct FFTContext {
89   int nbits;
90   int inverse;
91   uint16_t *revtab;
92   FFTComplex *tmp_buf;
93   int mdct_size; /* size of MDCT (i.e. number of input data * 2) */
94   int mdct_bits; /* n = 2^nbits */
95  /* pre/post rotation tables */
96   FFTSample *tcos;
97   FFTSample *tsin;
98  /**
99  * Do the permutation needed BEFORE calling fft_calc().
100  */
101   void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
102  /**
103  * Do a complex FFT with the parameters defined in ff_fft_init(). The
104  * input data must be permuted before. No 1.0/sqrt(n) normalization is done.
105  */
106   void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
107   void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
108   void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
109   void (*mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
110   void (*mdct_calcw)(struct FFTContext *s, FFTDouble *output, const FFTSample *input);
111   enum fft_permutation_type fft_permutation;
112   enum mdct_permutation_type mdct_permutation;
113 };
114 
115 #if CONFIG_HARDCODED_TABLES
116 #define COSTABLE_CONST const
117 #else
118  #define COSTABLE_CONST
119 #endif
120 
121  #define COSTABLE(size) \
122  COSTABLE_CONST DECLARE_ALIGNED(32, FFTSample, FFT_NAME(ff_cos_##size))[size/2]
123 
124 extern COSTABLE(16);
125 extern COSTABLE(32);
126 extern COSTABLE(64);
127 extern COSTABLE(128);
128 extern COSTABLE(256);
129 extern COSTABLE(512);
130 extern COSTABLE(1024);
131 extern COSTABLE(2048);
132 extern COSTABLE(4096);
133 extern COSTABLE(8192);
134 extern COSTABLE(16384);
135 extern COSTABLE(32768);
136 extern COSTABLE(65536);
137 extern COSTABLE_CONST FFTSample* const FFT_NAME(ff_cos_tabs)[17];
138 
139  #define ff_init_ff_cos_tabs FFT_NAME(ff_init_ff_cos_tabs)
140 
141 /**
142  * Initialize the cosine table in ff_cos_tabs[index]
143  * @param index index in ff_cos_tabs array of the table to initialize
144  */
145 void ff_init_ff_cos_tabs(int index);
146 
147  #define ff_fft_init FFT_NAME(ff_fft_init)
148  #define ff_fft_end FFT_NAME(ff_fft_end)
149 
150 /**
151  * Set up a complex FFT.
152  * @param nbits log2 of the length of the input array
153  * @param inverse if 0 perform the forward transform, if 1 perform the inverse
154  */
155 int ff_fft_init(FFTContext *s, int nbits, int inverse);
156 
157 void ff_fft_init_aarch64(FFTContext *s);
158 void ff_fft_init_x86(FFTContext *s);
159 void ff_fft_init_arm(FFTContext *s);
160 void ff_fft_init_mips(FFTContext *s);
161 void ff_fft_init_ppc(FFTContext *s);
162 
163 void ff_fft_fixed_init_arm(FFTContext *s);
164 
165 void ff_fft_end(FFTContext *s);
166 
167  #define ff_mdct_init FFT_NAME(ff_mdct_init)
168  #define ff_mdct_end FFT_NAME(ff_mdct_end)
169 
170 int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale);
171 void ff_mdct_end(FFTContext *s);
172 
173 #endif /* AVCODEC_FFT_H */
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