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 25 typedef struct AVTXContext AVTXContext; 26 27 typedef struct AVComplexFloat { 28 float re, im; 29 } AVComplexFloat; 30 31 typedef struct AVComplexDouble { 32 double re, im; 33 } AVComplexDouble; 34 35 typedef struct AVComplexInt32 { 36 int32_t re, im; 37 } 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 */ 45 AV_TX_FLOAT_FFT = 0, 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 */ 58 AV_TX_FLOAT_MDCT = 1, 59 60 /** 61 * Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble. 62 */ 63 AV_TX_DOUBLE_FFT = 2, 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 */ 69 AV_TX_DOUBLE_MDCT = 3, 70 71 /** 72 * Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32. 73 */ 74 AV_TX_INT32_FFT = 4, 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 */ 81 AV_TX_INT32_MDCT = 5, 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 */ 99 typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride); 100 101 /** 102 * Flags for av_tx_init() 103 */ 104 enum AVTXFlags { 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 */ 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); 129 130 /** 131 * Frees a context and sets ctx to NULL, does nothing when ctx == NULL 132 */ 133 void av_tx_uninit(AVTXContext **ctx); 134 135 #endif /* AVUTIL_TX_H */ 136