FFmpeg
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
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17  */
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 {
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  /**
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  *
53  * For inverse transforms, the stride specifies the spacing between each
54  * sample in the input array in bytes. The output will be a flat array.
55  * Stride must be a non-zero multiple of sizeof(float).
56  *
57  * NOTE: the inverse transform is half-length, meaning the output will not
58  * contain redundant data. This is what most codecs work with. To do a full
59  * inverse transform, set the AV_TX_FULL_IMDCT flag on init.
60  */
62 
63  /**
64  * Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
65  */
67 
68  /**
69  * Same as AV_TX_FLOAT_MDCT with data and scale type of double.
70  * Stride must be a non-zero multiple of sizeof(double).
71  */
73 
74  /**
75  * Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
76  */
78 
79  /**
80  * Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
81  * Only scale values less than or equal to 1.0 are supported.
82  * Stride must be a non-zero multiple of sizeof(int32_t).
83  */
85 };
86 
87 /**
88  * Function pointer to a function to perform the transform.
89  *
90  * @note Using a different context than the one allocated during av_tx_init()
91  * is not allowed.
92  *
93  * @param s the transform context
94  * @param out the output array
95  * @param in the input array
96  * @param stride the input or output stride in bytes
97  *
98  * The out and in arrays must be aligned to the maximum required by the CPU
99  * architecture unless the AV_TX_UNALIGNED flag was set in av_tx_init().
100  * The stride must follow the constraints the transform type has specified.
101  */
102 typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride);
103 
104 /**
105  * Flags for av_tx_init()
106  */
107 enum AVTXFlags {
108  /**
109  * Performs an in-place transformation on the input. The output argument
110  * of av_tn_fn() MUST match the input. May be unsupported or slower for some
111  * transform types.
112  */
113  AV_TX_INPLACE = 1ULL << 0,
114 
115  /**
116  * Relaxes alignment requirement for the in and out arrays of av_tx_fn().
117  * May be slower with certain transform types.
118  */
119  AV_TX_UNALIGNED = 1ULL << 1,
120 
121  /**
122  * Performs a full inverse MDCT rather than leaving out samples that can be
123  * derived through symmetry. Requires an output array of 'len' floats,
124  * rather than the usual 'len/2' floats.
125  * Ignored for all transforms but inverse MDCTs.
126  */
127  AV_TX_FULL_IMDCT = 1ULL << 2,
128 };
129 
130 /**
131  * Initialize a transform context with the given configuration
132  * (i)MDCTs with an odd length are currently not supported.
133  *
134  * @param ctx the context to allocate, will be NULL on error
135  * @param tx pointer to the transform function pointer to set
136  * @param type type the type of transform
137  * @param inv whether to do an inverse or a forward transform
138  * @param len the size of the transform in samples
139  * @param scale pointer to the value to scale the output if supported by type
140  * @param flags a bitmask of AVTXFlags or 0
141  *
142  * @return 0 on success, negative error code on failure
143  */
145  int inv, int len, const void *scale, uint64_t flags);
146 
147 /**
148  * Frees a context and sets ctx to NULL, does nothing when ctx == NULL
149  */
151 
152 #endif /* AVUTIL_TX_H */
stride
int stride
Definition: mace.c:144
AV_TX_DOUBLE_MDCT
@ AV_TX_DOUBLE_MDCT
Same as AV_TX_FLOAT_MDCT with data and scale type of double.
Definition: tx.h:72
out
FILE * out
Definition: movenc.c:54
AVTXContext
Definition: tx_priv.h:110
AVComplexDouble::im
double im
Definition: tx.h:32
AV_TX_DOUBLE_FFT
@ AV_TX_DOUBLE_FFT
Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
Definition: tx.h:66
AVComplexFloat
Definition: tx.h:27
av_tx_init
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...
Definition: tx.c:227
AVComplexFloat::im
float im
Definition: tx.h:28
AVComplexInt32::re
int32_t re
Definition: tx.h:36
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_tx_fn
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:102
AV_TX_FLOAT_MDCT
@ AV_TX_FLOAT_MDCT
Standard MDCT with sample data type of float and a scale type of float.
Definition: tx.h:61
AVComplexInt32
Definition: tx.h:35
s
#define s(width, name)
Definition: cbs_vp9.c:257
AV_TX_INT32_MDCT
@ AV_TX_INT32_MDCT
Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
Definition: tx.h:84
AV_TX_FLOAT_FFT
@ AV_TX_FLOAT_FFT
Standard complex to complex FFT with sample data type AVComplexFloat.
Definition: tx.h:45
ctx
AVFormatContext * ctx
Definition: movenc.c:48
AV_TX_FULL_IMDCT
@ AV_TX_FULL_IMDCT
Performs a full inverse MDCT rather than leaving out samples that can be derived through symmetry.
Definition: tx.h:127
AV_TX_INPLACE
@ AV_TX_INPLACE
Performs an in-place transformation on the input.
Definition: tx.h:113
AV_TX_UNALIGNED
@ AV_TX_UNALIGNED
Relaxes alignment requirement for the in and out arrays of av_tx_fn().
Definition: tx.h:119
AVTXType
AVTXType
Definition: tx.h:39
AVComplexFloat::re
float re
Definition: tx.h:28
AV_TX_INT32_FFT
@ AV_TX_INT32_FFT
Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
Definition: tx.h:77
AVTXFlags
AVTXFlags
Flags for av_tx_init()
Definition: tx.h:107
av_tx_uninit
void av_tx_uninit(AVTXContext **ctx)
Frees a context and sets ctx to NULL, does nothing when ctx == NULL.
Definition: tx.c:212
len
int len
Definition: vorbis_enc_data.h:426
AVComplexDouble
Definition: tx.h:31
AVComplexDouble::re
double re
Definition: tx.h:32
AVComplexInt32::im
int32_t im
Definition: tx.h:36
int32_t
int32_t
Definition: audioconvert.c:56
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561