2 * This file is part of FFmpeg.
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6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
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11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
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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.
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.
61 * Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
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).
69 AV_TX_DOUBLE_MDCT = 3,
72 * Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
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).
85 * Function pointer to a function to perform the transform.
87 * @note Using a different context than the one allocated during av_tx_init()
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
95 * The out and in arrays must be aligned to the maximum required by the CPU
97 * The stride must follow the constraints the transform type has specified.
99 typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride);
102 * Flags for av_tx_init()
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
110 AV_TX_INPLACE = 1ULL << 0,
114 * Initialize a transform context with the given configuration
115 * (i)MDCTs with an odd length are currently not supported.
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
125 * @return 0 on success, negative error code on failure
127 int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type,
128 int inv, int len, const void *scale, uint64_t flags);
131 * Frees a context and sets ctx to NULL, does nothing when ctx == NULL
133 void av_tx_uninit(AVTXContext **ctx);
135 #endif /* AVUTIL_TX_H */