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118 lines
3.0 KiB
118 lines
3.0 KiB
/* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#ifndef AVCODEC_AVFFT_H |
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#define AVCODEC_AVFFT_H |
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/** |
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* @file |
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* @ingroup lavc_fft |
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* FFT functions |
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*/ |
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/** |
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* @defgroup lavc_fft FFT functions |
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* @ingroup lavc_misc |
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* |
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* @{ |
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*/ |
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typedef float FFTSample; |
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typedef struct FFTComplex { |
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FFTSample re, im; |
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} FFTComplex; |
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typedef struct FFTContext FFTContext; |
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/** |
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* Set up a complex FFT. |
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* @param nbits log2 of the length of the input array |
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* @param inverse if 0 perform the forward transform, if 1 perform the inverse |
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*/ |
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FFTContext *av_fft_init(int nbits, int inverse); |
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/** |
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* Do the permutation needed BEFORE calling ff_fft_calc(). |
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*/ |
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void av_fft_permute(FFTContext *s, FFTComplex *z); |
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/** |
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* Do a complex FFT with the parameters defined in av_fft_init(). The |
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* input data must be permuted before. No 1.0/sqrt(n) normalization is done. |
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*/ |
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void av_fft_calc(FFTContext *s, FFTComplex *z); |
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void av_fft_end(FFTContext *s); |
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FFTContext *av_mdct_init(int nbits, int inverse, double scale); |
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void av_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input); |
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void av_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input); |
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void av_mdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input); |
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void av_mdct_end(FFTContext *s); |
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/* Real Discrete Fourier Transform */ |
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enum RDFTransformType { |
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DFT_R2C, |
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IDFT_C2R, |
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IDFT_R2C, |
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DFT_C2R, |
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}; |
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typedef struct RDFTContext RDFTContext; |
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/** |
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* Set up a real FFT. |
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* @param nbits log2 of the length of the input array |
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* @param trans the type of transform |
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*/ |
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RDFTContext *av_rdft_init(int nbits, enum RDFTransformType trans); |
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void av_rdft_calc(RDFTContext *s, FFTSample *data); |
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void av_rdft_end(RDFTContext *s); |
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/* Discrete Cosine Transform */ |
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typedef struct DCTContext DCTContext; |
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enum DCTTransformType { |
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DCT_II = 0, |
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DCT_III, |
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DCT_I, |
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DST_I, |
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}; |
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/** |
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* Set up DCT. |
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* |
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* @param nbits size of the input array: |
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* (1 << nbits) for DCT-II, DCT-III and DST-I |
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* (1 << nbits) + 1 for DCT-I |
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* @param type the type of transform |
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* |
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* @note the first element of the input of DST-I is ignored |
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*/ |
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DCTContext *av_dct_init(int nbits, enum DCTTransformType type); |
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void av_dct_calc(DCTContext *s, FFTSample *data); |
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void av_dct_end (DCTContext *s); |
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/** |
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* @} |
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*/ |
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#endif /* AVCODEC_AVFFT_H */
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