FFmpeg 4.4.5
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tx.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
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 AVUTIL_TX_H
20#define AVUTIL_TX_H
21
22#include <stdint.h>
23#include <stddef.h>
24
25typedef struct AVTXContext AVTXContext;
26
27typedef struct AVComplexFloat {
28 float re, im;
30
31typedef struct AVComplexDouble {
32 double re, im;
34
35typedef struct AVComplexInt32 {
36 int32_t re, im;
38
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 /**
48 * Standard MDCT with sample data type of float and a scale type of
49 * float. Length is the frame size, not the window size (which is 2x frame)
50 * For forward transforms, the stride specifies the spacing between each
51 * sample in the output array in bytes. The input must be a flat array.
52 * For inverse transforms, the stride specifies the spacing between each
53 * sample in the input array in bytes. The output will be a flat array.
54 * Stride must be a non-zero multiple of sizeof(float).
55 * NOTE: the inverse transform is half-length, meaning the output will not
56 * contain redundant data. This is what most codecs work with.
57 */
59
60 /**
61 * Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
62 */
64
65 /**
66 * Same as AV_TX_FLOAT_MDCT with data and scale type of double.
67 * Stride must be a non-zero multiple of sizeof(double).
68 */
70
71 /**
72 * Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
73 */
75
76 /**
77 * Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
78 * Only scale values less than or equal to 1.0 are supported.
79 * Stride must be a non-zero multiple of sizeof(int32_t).
80 */
82};
83
84/**
85 * Function pointer to a function to perform the transform.
86 *
87 * @note Using a different context than the one allocated during av_tx_init()
88 * is not allowed.
89 *
90 * @param s the transform context
91 * @param out the output array
92 * @param in the input array
93 * @param stride the input or output stride in bytes
94 *
95 * The out and in arrays must be aligned to the maximum required by the CPU
96 * architecture.
97 * The stride must follow the constraints the transform type has specified.
98 */
99typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride);
100
101/**
102 * Flags for av_tx_init()
103 */
105 /**
106 * Performs an in-place transformation on the input. The output argument
107 * of av_tn_fn() MUST match the input. May be unsupported or slower for some
108 * transform types.
109 */
110 AV_TX_INPLACE = 1ULL << 0,
111};
112
113/**
114 * Initialize a transform context with the given configuration
115 * (i)MDCTs with an odd length are currently not supported.
116 *
117 * @param ctx the context to allocate, will be NULL on error
118 * @param tx pointer to the transform function pointer to set
119 * @param type type the type of transform
120 * @param inv whether to do an inverse or a forward transform
121 * @param len the size of the transform in samples
122 * @param scale pointer to the value to scale the output if supported by type
123 * @param flags a bitmask of AVTXFlags or 0
124 *
125 * @return 0 on success, negative error code on failure
126 */
127int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type,
128 int inv, int len, const void *scale, uint64_t flags);
129
130/**
131 * Frees a context and sets ctx to NULL, does nothing when ctx == NULL
132 */
134
135#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
AVTXFlags
Flags for av_tx_init()
Definition tx.h:104
@ AV_TX_INPLACE
Performs an in-place transformation on the input.
Definition tx.h:110
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:69
@ AV_TX_INT32_FFT
Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
Definition tx.h:74
@ 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:58
@ AV_TX_DOUBLE_FFT
Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
Definition tx.h:63
@ AV_TX_INT32_MDCT
Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
Definition tx.h:81
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 (i)MDCTs with an odd length are currently...
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:99
struct AVTXContext AVTXContext
Definition tx.h:25