FFmpeg
avfft.h
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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
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8  *
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11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
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15  * License along with FFmpeg; if not, write to the Free Software
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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 {
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  */
49 
50 /**
51  * Do the permutation needed BEFORE calling ff_fft_calc().
52  */
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  */
60 
61 void av_fft_end(FFTContext *s);
62 
63 FFTContext *av_mdct_init(int nbits, int inverse, double scale);
67 void av_mdct_end(FFTContext *s);
68 
69 /* Real Discrete Fourier Transform */
70 
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  */
88 
89 /* Discrete Cosine Transform */
90 
91 typedef struct DCTContext DCTContext;
92 
94  DCT_II = 0,
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  */
112 void av_dct_end (DCTContext *s);
113 
114 /**
115  * @}
116  */
117 
118 #endif /* AVCODEC_AVFFT_H */
int nbits
Definition: rdft.h:29
Definition: avfft.h:75
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
void av_fft_end(FFTContext *s)
Definition: avfft.c:48
void av_mdct_end(FFTContext *s)
Definition: avfft.h:95
FFTContext * av_mdct_init(int nbits, int inverse, double scale)
DCTContext * av_dct_init(int nbits, enum DCTTransformType type)
Set up DCT.
GLint GLenum type
Definition: opengl_enc.c:104
FFTSample re
Definition: avfft.h:38
void av_fft_permute(FFTContext *s, FFTComplex *z)
Do the permutation needed BEFORE calling ff_fft_calc().
Definition: avfft.c:38
void FFTComplex
Definition: tx_priv.h:38
int nbits
Definition: dct.h:33
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce output
RDFTransformType
Definition: avfft.h:71
void av_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input)
DCTTransformType
Definition: avfft.h:93
Definition: avfft.h:73
FFTContext * av_fft_init(int nbits, int inverse)
Set up a complex FFT.
Definition: avfft.c:28
float FFTSample
Definition: avfft.h:35
void av_rdft_calc(RDFTContext *s, FFTSample *data)
Definition: fft.h:88
Definition: avfft.h:97
int nbits
Definition: fft.h:89
Definition: dct.h:32
#define s(width, name)
Definition: cbs_vp9.c:257
Definition: avfft.h:72
void av_rdft_end(RDFTContext *s)
RDFTContext * av_rdft_init(int nbits, enum RDFTransformType trans)
Set up a real FFT.
Definition: avfft.h:74
void av_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input)
void av_dct_end(DCTContext *s)
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some input
FFTSample im
Definition: avfft.h:38
Definition: avfft.h:94
void av_dct_calc(DCTContext *s, FFTSample *data)
void av_mdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input)
static uint32_t inverse(uint32_t v)
find multiplicative inverse modulo 2 ^ 32
Definition: asfcrypt.c:35
Definition: avfft.h:96
void av_fft_calc(FFTContext *s, FFTComplex *z)
Do a complex FFT with the parameters defined in av_fft_init().
Definition: avfft.c:43