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comparison lib/libavcodec/avfft.h @ 2134:992d2e6f907d

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preparation for libavcodec
author zipi
date Tue, 31 Dec 2013 14:52:14 +0000
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2133:e378232bfd36 2134:992d2e6f907d
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 * @param nbits size of the input array:
103 * (1 << nbits) for DCT-II, DCT-III and DST-I
104 * (1 << nbits) + 1 for DCT-I
105 *
106 * @note the first element of the input of DST-I is ignored
107 */
108 DCTContext *av_dct_init(int nbits, enum DCTTransformType type);
109 void av_dct_calc(DCTContext *s, FFTSample *data);
110 void av_dct_end (DCTContext *s);
111
112 /**
113 * @}
114 */
115
116 #endif /* AVCODEC_AVFFT_H */