FFmpeg/libavcodec/avfft.h

/*
 * 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

#include "libavutil/attributes.h"
#include "version_major.h"
#if FF_API_AVFFT

/**
 * @file
 * @ingroup lavc_fft
 * FFT functions
 */

/**
 * @defgroup lavc_fft FFT functions
 * @ingroup lavc_misc
 *
 * @{
 */

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
 * @deprecated use av_tx_init from libavutil/tx.h with a type of AV_TX_FLOAT_FFT
 */
attribute_deprecated
FFTContext *av_fft_init(int nbits, int inverse);

/**
 * Do the permutation needed BEFORE calling ff_fft_calc().
 * @deprecated without replacement
 */
attribute_deprecated
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.
 * @deprecated use the av_tx_fn value returned by av_tx_init, which also does permutation
 */
attribute_deprecated
void av_fft_calc(FFTContext *s, FFTComplex *z);

attribute_deprecated
void av_fft_end(FFTContext *s);

/**
 * @deprecated use av_tx_init from libavutil/tx.h with a type of AV_TX_FLOAT_MDCT,
 * with a flag of AV_TX_FULL_IMDCT for a replacement to av_imdct_calc.
 */
attribute_deprecated
FFTContext *av_mdct_init(int nbits, int inverse, double scale);
attribute_deprecated
void av_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input);
attribute_deprecated
void av_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input);
attribute_deprecated
void av_mdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input);
attribute_deprecated
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
 *
 * @deprecated use av_tx_init from libavutil/tx.h with a type of AV_TX_FLOAT_RDFT
 */
attribute_deprecated
RDFTContext *av_rdft_init(int nbits, enum RDFTransformType trans);
attribute_deprecated
void av_rdft_calc(RDFTContext *s, FFTSample *data);
attribute_deprecated
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
 * @param type            the type of transform
 *
 * @note the first element of the input of DST-I is ignored
 *
 * @deprecated use av_tx_init from libavutil/tx.h with an appropriate type of AV_TX_FLOAT_DCT
 */
attribute_deprecated
DCTContext *av_dct_init(int nbits, enum DCTTransformType type);
attribute_deprecated
void av_dct_calc(DCTContext *s, FFTSample *data);
attribute_deprecated
void av_dct_end (DCTContext *s);

/**
 * @}
 */

#endif /* FF_API_AVFFT */
#endif /* AVCODEC_AVFFT_H */