FFmpeg
avfft.h
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3  *
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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 */
av_fft_end
void av_fft_end(FFTContext *s)
Definition: avfft.c:48
av_imdct_calc
void av_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input)
DCT_I
@ DCT_I
Definition: avfft.h:96
output
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
Definition: filter_design.txt:225
DFT_C2R
@ DFT_C2R
Definition: avfft.h:75
data
const char data[16]
Definition: mxf.c:143
av_fft_permute
void av_fft_permute(FFTContext *s, FFTComplex *z)
Do the permutation needed BEFORE calling ff_fft_calc().
Definition: avfft.c:38
av_dct_init
DCTContext * av_dct_init(int nbits, enum DCTTransformType type)
Set up DCT.
DCT_III
@ DCT_III
Definition: avfft.h:95
IDFT_C2R
@ IDFT_C2R
Definition: avfft.h:73
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
av_dct_end
void av_dct_end(DCTContext *s)
s
#define s(width, name)
Definition: cbs_vp9.c:257
av_rdft_calc
void av_rdft_calc(RDFTContext *s, FFTSample *data)
IDFT_R2C
@ IDFT_R2C
Definition: avfft.h:74
av_dct_calc
void av_dct_calc(DCTContext *s, FFTSample *data)
av_mdct_init
FFTContext * av_mdct_init(int nbits, int inverse, double scale)
RDFTContext::nbits
int nbits
Definition: rdft.h:29
av_mdct_end
void av_mdct_end(FFTContext *s)
DFT_R2C
@ DFT_R2C
Definition: avfft.h:72
FFTSample
float FFTSample
Definition: avfft.h:35
FFTComplex
void FFTComplex
Definition: tx_priv.h:43
FFTContext::nbits
int nbits
Definition: fft.h:84
av_rdft_init
RDFTContext * av_rdft_init(int nbits, enum RDFTransformType trans)
Set up a real FFT.
FFTComplex::im
FFTSample im
Definition: avfft.h:38
FFTComplex::re
FFTSample re
Definition: avfft.h:38
DCTContext::nbits
int nbits
Definition: dct.h:33
input
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
Definition: filter_design.txt:172
DST_I
@ DST_I
Definition: avfft.h:97
FFTContext
Definition: fft.h:83
RDFTContext
Definition: rdft.h:28
RDFTransformType
RDFTransformType
Definition: avfft.h:71
DCTContext
Definition: dct.h:32
av_fft_init
FFTContext * av_fft_init(int nbits, int inverse)
Set up a complex FFT.
Definition: avfft.c:28
inverse
static int inverse(AudioFWTDNContext *s, double **in, int *in_length, double *out, int out_length, int ch, uint64_t sn)
Definition: af_afwtdn.c:791
DCT_II
@ DCT_II
Definition: avfft.h:94
av_rdft_end
void av_rdft_end(RDFTContext *s)
av_fft_calc
void av_fft_calc(FFTContext *s, FFTComplex *z)
Do a complex FFT with the parameters defined in av_fft_init().
Definition: avfft.c:43
av_mdct_calc
void av_mdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input)
DCTTransformType
DCTTransformType
Definition: avfft.h:93
av_imdct_half
void av_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input)
FFTComplex
Definition: avfft.h:37