yading@10: /*
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #ifndef AVCODEC_AVFFT_H
yading@10: #define AVCODEC_AVFFT_H
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * @ingroup lavc_fft
yading@10:  * FFT functions
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @defgroup lavc_fft FFT functions
yading@10:  * @ingroup lavc_misc
yading@10:  *
yading@10:  * @{
yading@10:  */
yading@10: 
yading@10: typedef float FFTSample;
yading@10: 
yading@10: typedef struct FFTComplex {
yading@10:     FFTSample re, im;
yading@10: } FFTComplex;
yading@10: 
yading@10: typedef struct FFTContext FFTContext;
yading@10: 
yading@10: /**
yading@10:  * Set up a complex FFT.
yading@10:  * @param nbits           log2 of the length of the input array
yading@10:  * @param inverse         if 0 perform the forward transform, if 1 perform the inverse
yading@10:  */
yading@10: FFTContext *av_fft_init(int nbits, int inverse);
yading@10: 
yading@10: /**
yading@10:  * Do the permutation needed BEFORE calling ff_fft_calc().
yading@10:  */
yading@10: void av_fft_permute(FFTContext *s, FFTComplex *z);
yading@10: 
yading@10: /**
yading@10:  * Do a complex FFT with the parameters defined in av_fft_init(). The
yading@10:  * input data must be permuted before. No 1.0/sqrt(n) normalization is done.
yading@10:  */
yading@10: void av_fft_calc(FFTContext *s, FFTComplex *z);
yading@10: 
yading@10: void av_fft_end(FFTContext *s);
yading@10: 
yading@10: FFTContext *av_mdct_init(int nbits, int inverse, double scale);
yading@10: void av_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input);
yading@10: void av_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input);
yading@10: void av_mdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input);
yading@10: void av_mdct_end(FFTContext *s);
yading@10: 
yading@10: /* Real Discrete Fourier Transform */
yading@10: 
yading@10: enum RDFTransformType {
yading@10:     DFT_R2C,
yading@10:     IDFT_C2R,
yading@10:     IDFT_R2C,
yading@10:     DFT_C2R,
yading@10: };
yading@10: 
yading@10: typedef struct RDFTContext RDFTContext;
yading@10: 
yading@10: /**
yading@10:  * Set up a real FFT.
yading@10:  * @param nbits           log2 of the length of the input array
yading@10:  * @param trans           the type of transform
yading@10:  */
yading@10: RDFTContext *av_rdft_init(int nbits, enum RDFTransformType trans);
yading@10: void av_rdft_calc(RDFTContext *s, FFTSample *data);
yading@10: void av_rdft_end(RDFTContext *s);
yading@10: 
yading@10: /* Discrete Cosine Transform */
yading@10: 
yading@10: typedef struct DCTContext DCTContext;
yading@10: 
yading@10: enum DCTTransformType {
yading@10:     DCT_II = 0,
yading@10:     DCT_III,
yading@10:     DCT_I,
yading@10:     DST_I,
yading@10: };
yading@10: 
yading@10: /**
yading@10:  * Set up DCT.
yading@10:  * @param nbits           size of the input array:
yading@10:  *                        (1 << nbits)     for DCT-II, DCT-III and DST-I
yading@10:  *                        (1 << nbits) + 1 for DCT-I
yading@10:  *
yading@10:  * @note the first element of the input of DST-I is ignored
yading@10:  */
yading@10: DCTContext *av_dct_init(int nbits, enum DCTTransformType type);
yading@10: void av_dct_calc(DCTContext *s, FFTSample *data);
yading@10: void av_dct_end (DCTContext *s);
yading@10: 
yading@10: /**
yading@10:  * @}
yading@10:  */
yading@10: 
yading@10: #endif /* AVCODEC_AVFFT_H */