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Diffstat (limited to 'dependencies/include/libavutil/tx.h')
| -rw-r--r-- | dependencies/include/libavutil/tx.h | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/dependencies/include/libavutil/tx.h b/dependencies/include/libavutil/tx.h new file mode 100644 index 0000000..064edbc --- /dev/null +++ b/dependencies/include/libavutil/tx.h @@ -0,0 +1,176 @@ +/* + * 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. + * + * For forward transforms (R2C), stride must be the spacing between two + * samples in bytes. For inverse transforms, the stride must be set + * to the spacing between two complex values 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, + + /** + * Real to real (DCT) transforms. + * + * The forward transform is a DCT-II. + * The inverse transform is a DCT-III. + * + * The input array is always overwritten. DCT-III requires that the + * input be padded with 2 extra samples. Stride must be set to the + * spacing between two samples in bytes. + */ + AV_TX_FLOAT_DCT = 9, + AV_TX_DOUBLE_DCT = 10, + AV_TX_INT32_DCT = 11, + + /* 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 { + /** + * Allows for in-place transformations, where input == output. + * 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 */ |