| /* |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #ifndef AVUTIL_TX_H |
| #define AVUTIL_TX_H |
| |
| #include <stdint.h> |
| #include <stddef.h> |
| |
| typedef struct AVTXContext AVTXContext; |
| |
| typedef struct AVComplexFloat { |
| float re, im; |
| } AVComplexFloat; |
| |
| typedef struct AVComplexDouble { |
| double re, im; |
| } AVComplexDouble; |
| |
| typedef struct AVComplexInt32 { |
| int32_t re, im; |
| } AVComplexInt32; |
| |
| enum AVTXType { |
| /** |
| * Standard complex to complex FFT with sample data type of AVComplexFloat, |
| * AVComplexDouble or AVComplexInt32, for each respective variant. |
| * |
| * Output is not 1/len normalized. Scaling currently unsupported. |
| * The stride parameter must be set to the size of a single sample in bytes. |
| */ |
| AV_TX_FLOAT_FFT = 0, |
| AV_TX_DOUBLE_FFT = 2, |
| AV_TX_INT32_FFT = 4, |
| |
| /** |
| * Standard MDCT with a sample data type of float, double or int32_t, |
| * respecively. For the float and int32 variants, the scale type is |
| * 'float', while for the double variant, it's 'double'. |
| * If scale is NULL, 1.0 will be used as a default. |
| * |
| * Length is the frame size, not the window size (which is 2x frame). |
| * For forward transforms, the stride specifies the spacing between each |
| * sample in the output array in bytes. The input must be a flat array. |
| * |
| * For inverse transforms, the stride specifies the spacing between each |
| * sample in the input array in bytes. The output must be a flat array. |
| * |
| * NOTE: the inverse transform is half-length, meaning the output will not |
| * contain redundant data. This is what most codecs work with. To do a full |
| * inverse transform, set the AV_TX_FULL_IMDCT flag on init. |
| */ |
| AV_TX_FLOAT_MDCT = 1, |
| AV_TX_DOUBLE_MDCT = 3, |
| AV_TX_INT32_MDCT = 5, |
| |
| /** |
| * Real to complex and complex to real DFTs. |
| * For the float and int32 variants, the scale type is 'float', while for |
| * the double variant, it's a 'double'. If scale is NULL, 1.0 will be used |
| * as a default. |
| * |
| * The stride parameter must be set to the size of a single sample in bytes. |
| * |
| * The forward transform performs a real-to-complex DFT of N samples to |
| * N/2+1 complex values. |
| * |
| * The inverse transform performs a complex-to-real DFT of N/2+1 complex |
| * values to N real samples. The output is not normalized, but can be |
| * made so by setting the scale value to 1.0/len. |
| * NOTE: the inverse transform always overwrites the input. |
| */ |
| AV_TX_FLOAT_RDFT = 6, |
| AV_TX_DOUBLE_RDFT = 7, |
| AV_TX_INT32_RDFT = 8, |
| |
| /* Not part of the API, do not use */ |
| AV_TX_NB, |
| }; |
| |
| /** |
| * Function pointer to a function to perform the transform. |
| * |
| * @note Using a different context than the one allocated during av_tx_init() |
| * is not allowed. |
| * |
| * @param s the transform context |
| * @param out the output array |
| * @param in the input array |
| * @param stride the input or output stride in bytes |
| * |
| * The out and in arrays must be aligned to the maximum required by the CPU |
| * architecture unless the AV_TX_UNALIGNED flag was set in av_tx_init(). |
| * The stride must follow the constraints the transform type has specified. |
| */ |
| typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride); |
| |
| /** |
| * Flags for av_tx_init() |
| */ |
| enum AVTXFlags { |
| /** |
| * Performs an in-place transformation on the input. The output argument |
| * of av_tn_fn() MUST match the input. May be unsupported or slower for some |
| * transform types. |
| */ |
| AV_TX_INPLACE = 1ULL << 0, |
| |
| /** |
| * Relaxes alignment requirement for the in and out arrays of av_tx_fn(). |
| * May be slower with certain transform types. |
| */ |
| AV_TX_UNALIGNED = 1ULL << 1, |
| |
| /** |
| * Performs a full inverse MDCT rather than leaving out samples that can be |
| * derived through symmetry. Requires an output array of 'len' floats, |
| * rather than the usual 'len/2' floats. |
| * Ignored for all transforms but inverse MDCTs. |
| */ |
| AV_TX_FULL_IMDCT = 1ULL << 2, |
| }; |
| |
| /** |
| * Initialize a transform context with the given configuration |
| * (i)MDCTs with an odd length are currently not supported. |
| * |
| * @param ctx the context to allocate, will be NULL on error |
| * @param tx pointer to the transform function pointer to set |
| * @param type type the type of transform |
| * @param inv whether to do an inverse or a forward transform |
| * @param len the size of the transform in samples |
| * @param scale pointer to the value to scale the output if supported by type |
| * @param flags a bitmask of AVTXFlags or 0 |
| * |
| * @return 0 on success, negative error code on failure |
| */ |
| int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type, |
| int inv, int len, const void *scale, uint64_t flags); |
| |
| /** |
| * Frees a context and sets *ctx to NULL, does nothing when *ctx == NULL. |
| */ |
| void av_tx_uninit(AVTXContext **ctx); |
| |
| #endif /* AVUTIL_TX_H */ |