blob: 0c0f9b8d8dae13c14a8cd91a1c4234b07821e916
1 | /* |
2 | * This file is part of FFmpeg. |
3 | * |
4 | * FFmpeg is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU Lesser General Public |
6 | * License as published by the Free Software Foundation; either |
7 | * version 2.1 of the License, or (at your option) any later version. |
8 | * |
9 | * FFmpeg is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | * Lesser General Public License for more details. |
13 | * |
14 | * You should have received a copy of the GNU Lesser General Public |
15 | * License along with FFmpeg; if not, write to the Free Software |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
17 | */ |
18 | |
19 | #ifndef AVCODEC_AVFFT_H |
20 | #define AVCODEC_AVFFT_H |
21 | |
22 | /** |
23 | * @file |
24 | * @ingroup lavc_fft |
25 | * FFT functions |
26 | */ |
27 | |
28 | /** |
29 | * @defgroup lavc_fft FFT functions |
30 | * @ingroup lavc_misc |
31 | * |
32 | * @{ |
33 | */ |
34 | |
35 | typedef float FFTSample; |
36 | |
37 | typedef struct FFTComplex { |
38 | FFTSample re, im; |
39 | } FFTComplex; |
40 | |
41 | typedef struct FFTContext FFTContext; |
42 | |
43 | /** |
44 | * Set up a complex FFT. |
45 | * @param nbits log2 of the length of the input array |
46 | * @param inverse if 0 perform the forward transform, if 1 perform the inverse |
47 | */ |
48 | FFTContext *av_fft_init(int nbits, int inverse); |
49 | |
50 | /** |
51 | * Do the permutation needed BEFORE calling ff_fft_calc(). |
52 | */ |
53 | void av_fft_permute(FFTContext *s, FFTComplex *z); |
54 | |
55 | /** |
56 | * Do a complex FFT with the parameters defined in av_fft_init(). The |
57 | * input data must be permuted before. No 1.0/sqrt(n) normalization is done. |
58 | */ |
59 | void av_fft_calc(FFTContext *s, FFTComplex *z); |
60 | |
61 | void av_fft_end(FFTContext *s); |
62 | |
63 | FFTContext *av_mdct_init(int nbits, int inverse, double scale); |
64 | void av_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input); |
65 | void av_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input); |
66 | void av_mdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input); |
67 | void av_mdct_end(FFTContext *s); |
68 | |
69 | /* Real Discrete Fourier Transform */ |
70 | |
71 | enum RDFTransformType { |
72 | DFT_R2C, |
73 | IDFT_C2R, |
74 | IDFT_R2C, |
75 | DFT_C2R, |
76 | }; |
77 | |
78 | typedef struct RDFTContext RDFTContext; |
79 | |
80 | /** |
81 | * Set up a real FFT. |
82 | * @param nbits log2 of the length of the input array |
83 | * @param trans the type of transform |
84 | */ |
85 | RDFTContext *av_rdft_init(int nbits, enum RDFTransformType trans); |
86 | void av_rdft_calc(RDFTContext *s, FFTSample *data); |
87 | void av_rdft_end(RDFTContext *s); |
88 | |
89 | /* Discrete Cosine Transform */ |
90 | |
91 | typedef struct DCTContext DCTContext; |
92 | |
93 | enum DCTTransformType { |
94 | DCT_II = 0, |
95 | DCT_III, |
96 | DCT_I, |
97 | DST_I, |
98 | }; |
99 | |
100 | /** |
101 | * Set up DCT. |
102 | * |
103 | * @param nbits size of the input array: |
104 | * (1 << nbits) for DCT-II, DCT-III and DST-I |
105 | * (1 << nbits) + 1 for DCT-I |
106 | * @param type the type of transform |
107 | * |
108 | * @note the first element of the input of DST-I is ignored |
109 | */ |
110 | DCTContext *av_dct_init(int nbits, enum DCTTransformType type); |
111 | void av_dct_calc(DCTContext *s, FFTSample *data); |
112 | void av_dct_end (DCTContext *s); |
113 | |
114 | /** |
115 | * @} |
116 | */ |
117 | |
118 | #endif /* AVCODEC_AVFFT_H */ |
119 |