FFmpeg  4.3.1
tx.h
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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
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12  * Lesser General Public License for more details.
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18 
19 #ifndef AVUTIL_TX_H
20 #define AVUTIL_TX_H
21 
22 #include <stdint.h>
23 #include <stddef.h>
24 
25 typedef struct AVTXContext AVTXContext;
26 
27 typedef struct AVComplexFloat {
28  float re, im;
30 
31 typedef struct AVComplexDouble {
32  double re, im;
34 
35 typedef struct AVComplexInt32 {
36  int32_t re, im;
38 
39 enum AVTXType {
40  /**
41  * Standard complex to complex FFT with sample data type AVComplexFloat.
42  * Output is not 1/len normalized. Scaling currently unsupported.
43  * The stride parameter is ignored.
44  */
46  /**
47  * Standard MDCT with sample data type of float and a scale type of
48  * float. Length is the frame size, not the window size (which is 2x frame)
49  * For forward transforms, the stride specifies the spacing between each
50  * sample in the output array in bytes. The input must be a flat array.
51  * For inverse transforms, the stride specifies the spacing between each
52  * sample in the input array in bytes. The output will be a flat array.
53  * Stride must be a non-zero multiple of sizeof(float).
54  */
56  /**
57  * Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
58  */
60  /**
61  * Same as AV_TX_FLOAT_MDCT with data and scale type of double.
62  * Stride must be a non-zero multiple of sizeof(double).
63  */
65  /**
66  * Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
67  */
69  /**
70  * Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
71  * Only scale values less than or equal to 1.0 are supported.
72  * Stride must be a non-zero multiple of sizeof(int32_t).
73  */
75 };
76 
77 /**
78  * Function pointer to a function to perform the transform.
79  *
80  * @note Using a different context than the one allocated during av_tx_init()
81  * is not allowed.
82  *
83  * @param s the transform context
84  * @param out the output array
85  * @param in the input array
86  * @param stride the input or output stride in bytes
87  *
88  * The out and in arrays must be aligned to the maximum required by the CPU
89  * architecture.
90  * The stride must follow the constraints the transform type has specified.
91  */
92 typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride);
93 
94 /**
95  * Initialize a transform context with the given configuration
96  * Currently power of two lengths from 2 to 131072 are supported, along with
97  * any length decomposable to a power of two and either 3, 5 or 15.
98  *
99  * @param ctx the context to allocate, will be NULL on error
100  * @param tx pointer to the transform function pointer to set
101  * @param type type the type of transform
102  * @param inv whether to do an inverse or a forward transform
103  * @param len the size of the transform in samples
104  * @param scale pointer to the value to scale the output if supported by type
105  * @param flags currently unused
106  *
107  * @return 0 on success, negative error code on failure
108  */
109 int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type,
110  int inv, int len, const void *scale, uint64_t flags);
111 
112 /**
113  * Frees a context and sets ctx to NULL, does nothing when ctx == NULL
114  */
116 
117 #endif /* AVUTIL_TX_H */
double re
Definition: tx.h:32
double im
Definition: tx.h:32
float im
Definition: tx.h:28
float re
Definition: tx.h:28
int32_t re
Definition: tx.h:36
int32_t im
Definition: tx.h:36
void av_tx_uninit(AVTXContext **ctx)
Frees a context and sets ctx to NULL, does nothing when ctx == NULL.
AVTXType
Definition: tx.h:39
@ AV_TX_DOUBLE_MDCT
Same as AV_TX_FLOAT_MDCT with data and scale type of double.
Definition: tx.h:64
@ AV_TX_INT32_FFT
Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
Definition: tx.h:68
@ AV_TX_FLOAT_FFT
Standard complex to complex FFT with sample data type AVComplexFloat.
Definition: tx.h:45
@ AV_TX_FLOAT_MDCT
Standard MDCT with sample data type of float and a scale type of float.
Definition: tx.h:55
@ AV_TX_DOUBLE_FFT
Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
Definition: tx.h:59
@ AV_TX_INT32_MDCT
Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
Definition: tx.h:74
int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type, int inv, int len, const void *scale, uint64_t flags)
Initialize a transform context with the given configuration Currently power of two lengths from 2 to ...
void(* av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride)
Function pointer to a function to perform the transform.
Definition: tx.h:92
struct AVTXContext AVTXContext
Definition: tx.h:25