ffmpeg.libavutil.tx source code

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 module ffmpeg.libavutil.tx;
19 
20 import ffmpeg.libavutil;
21 
22 extern (C) @nogc nothrow:
23 
24 struct AVTXContext;
25 
26 struct AVComplexFloat
27 {
28     float re;
29     float im;
30 }
31 
32 struct AVComplexDouble
33 {
34     double re;
35     double im;
36 }
37 
38 struct AVComplexInt32
39 {
40     int re;
41     int im;
42 }
43 
44 enum AVTXType
45 {
46     /**
47      * Standard complex to complex FFT with sample data type AVComplexFloat.
48      * Output is not 1/len normalized. Scaling currently unsupported.
49      * The stride parameter is ignored.
50      */
51     AV_TX_FLOAT_FFT = 0,
52 
53     /**
54      * Standard MDCT with sample data type of float and a scale type of
55      * float. Length is the frame size, not the window size (which is 2x frame)
56      * For forward transforms, the stride specifies the spacing between each
57      * sample in the output array in bytes. The input must be a flat array.
58      * For inverse transforms, the stride specifies the spacing between each
59      * sample in the input array in bytes. The output will be a flat array.
60      * Stride must be a non-zero multiple of sizeof(float).
61      * NOTE: the inverse transform is half-length, meaning the output will not
62      * contain redundant data. This is what most codecs work with.
63      */
64     AV_TX_FLOAT_MDCT = 1,
65 
66     /**
67      * Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
68      */
69     AV_TX_DOUBLE_FFT = 2,
70 
71     /**
72      * Same as AV_TX_FLOAT_MDCT with data and scale type of double.
73      * Stride must be a non-zero multiple of sizeof(double).
74      */
75     AV_TX_DOUBLE_MDCT = 3,
76 
77     /**
78      * Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
79      */
80     AV_TX_INT32_FFT = 4,
81 
82     /**
83      * Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
84      * Only scale values less than or equal to 1.0 are supported.
85      * Stride must be a non-zero multiple of sizeof(int32_t).
86      */
87     AV_TX_INT32_MDCT = 5
88 }
89 
90 /**
91  * Function pointer to a function to perform the transform.
92  *
93  * @note Using a different context than the one allocated during av_tx_init()
94  * is not allowed.
95  *
96  * @param s the transform context
97  * @param out the output array
98  * @param in the input array
99  * @param stride the input or output stride in bytes
100  *
101  * The out and in arrays must be aligned to the maximum required by the CPU
102  * architecture.
103  * The stride must follow the constraints the transform type has specified.
104  */
105 alias av_tx_fn = void function (AVTXContext* s, void* out_, void* in_, ptrdiff_t stride);
106 
107 /**
108  * Flags for av_tx_init()
109  */
110 enum AVTXFlags
111 {
112     /**
113      * Performs an in-place transformation on the input. The output argument
114      * of av_tn_fn() MUST match the input. May be unsupported or slower for some
115      * transform types.
116      */
117     AV_TX_INPLACE = 1UL << 0
118 }
119 
120 /**
121  * Initialize a transform context with the given configuration
122  * (i)MDCTs with an odd length are currently not supported.
123  *
124  * @param ctx the context to allocate, will be NULL on error
125  * @param tx pointer to the transform function pointer to set
126  * @param type type the type of transform
127  * @param inv whether to do an inverse or a forward transform
128  * @param len the size of the transform in samples
129  * @param scale pointer to the value to scale the output if supported by type
130  * @param flags a bitmask of AVTXFlags or 0
131  *
132  * @return 0 on success, negative error code on failure
133  */
134 int av_tx_init (
135     AVTXContext** ctx,
136     av_tx_fn* tx,
137     AVTXType type,
138     int inv,
139     int len,
140     const(void)* scale,
141     ulong flags);
142 
143 /**
144  * Frees a context and sets ctx to NULL, does nothing when ctx == NULL
145  */
146 void av_tx_uninit (AVTXContext** ctx);
147 
148 /* AVUTIL_TX_H */