2 * This file is part of FFmpeg.
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.
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.
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
25 typedef struct AVTXContext AVTXContext;
27 typedef struct AVComplexFloat {
31 typedef struct AVComplexDouble {
35 typedef struct AVComplexInt32 {
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.
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 * NOTE: the inverse transform is half-length, meaning the output will not
55 * contain redundant data. This is what most codecs work with.
59 * Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
63 * Same as AV_TX_FLOAT_MDCT with data and scale type of double.
64 * Stride must be a non-zero multiple of sizeof(double).
66 AV_TX_DOUBLE_MDCT = 3,
68 * Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
72 * Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
73 * Only scale values less than or equal to 1.0 are supported.
74 * Stride must be a non-zero multiple of sizeof(int32_t).
80 * Function pointer to a function to perform the transform.
82 * @note Using a different context than the one allocated during av_tx_init()
85 * @param s the transform context
86 * @param out the output array
87 * @param in the input array
88 * @param stride the input or output stride in bytes
90 * The out and in arrays must be aligned to the maximum required by the CPU
92 * The stride must follow the constraints the transform type has specified.
94 typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride);
97 * Initialize a transform context with the given configuration
98 * (i)MDCTs with an odd length are currently not supported.
100 * @param ctx the context to allocate, will be NULL on error
101 * @param tx pointer to the transform function pointer to set
102 * @param type type the type of transform
103 * @param inv whether to do an inverse or a forward transform
104 * @param len the size of the transform in samples
105 * @param scale pointer to the value to scale the output if supported by type
106 * @param flags currently unused
108 * @return 0 on success, negative error code on failure
110 int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type,
111 int inv, int len, const void *scale, uint64_t flags);
114 * Frees a context and sets ctx to NULL, does nothing when ctx == NULL
116 void av_tx_uninit(AVTXContext **ctx);
118 #endif /* AVUTIL_TX_H */