/*
  * 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 AVCODEC_AVFFT_H
 #define AVCODEC_AVFFT_H
 
 typedef float FFTSample;
 
 typedef struct FFTComplex {
     FFTSample re, im;
 } FFTComplex;
 
 typedef struct FFTContext FFTContext;
 
 /**
  * Set up a complex FFT.
  * @param nbits           log2 of the length of the input array
  * @param inverse         if 0 perform the forward transform, if 1 perform the inverse
  */
 FFTContext *av_fft_init(int nbits, int inverse);
 
 /**
  * Do the permutation needed BEFORE calling ff_fft_calc().
  */
 void av_fft_permute(FFTContext *s, FFTComplex *z);
 
 /**
  * Do a complex FFT with the parameters defined in av_fft_init(). The
  * input data must be permuted before. No 1.0/sqrt(n) normalization is done.
  */
 void av_fft_calc(FFTContext *s, FFTComplex *z);
 
 void av_fft_end(FFTContext *s);
 
 FFTContext *av_mdct_init(int nbits, int inverse, double scale);
 void av_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input);
 void av_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input);
 void av_mdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input);
 void av_mdct_end(FFTContext *s);
 
 /* Real Discrete Fourier Transform */
 
 enum RDFTransformType {
     DFT_R2C,
     IDFT_C2R,
     IDFT_R2C,
     DFT_C2R,
 };
 
 typedef struct RDFTContext RDFTContext;
 
 /**
  * Set up a real FFT.
  * @param nbits           log2 of the length of the input array
  * @param trans           the type of transform
  */
 RDFTContext *av_rdft_init(int nbits, enum RDFTransformType trans);
 void av_rdft_calc(RDFTContext *s, FFTSample *data);
 void av_rdft_end(RDFTContext *s);
 
 /* Discrete Cosine Transform */
 
 typedef struct DCTContext DCTContext;
 

 enum DCTTransformType {
     DCT_II = 0,
     DCT_III,
     DCT_I,
     DST_I,
 };
 

 /**

  * Set up DCT.

  * @param nbits           size of the input array:
  *                        (1 << nbits)     for DCT-II, DCT-III and DST-I
  *                        (1 << nbits) + 1 for DCT-I
  *
  * @note the first element of the input of DST-I is ignored

  */

 DCTContext *av_dct_init(int nbits, enum DCTTransformType type);

 void av_dct_calc(DCTContext *s, FFTSample *data);
 void av_dct_end (DCTContext *s);
 
 #endif /* AVCODEC_AVFFT_H */