+
−/*
+
− * This file is part of Libav.
+
− *
+
− * Libav 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.
+
− *
+
− * Libav 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 Libav; 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
+
−
+
−/**
+
− * @file
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− * @ingroup lavc_fft
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− * FFT functions
+
− */
+
−
+
−/**
+
− * @defgroup lavc_fft FFT functions
+
− * @ingroup lavc_misc
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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;
+
−} FFTComplex;
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−
+
−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
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− * 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 {
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−    DFT_R2C,
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−    IDFT_C2R,
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−    IDFT_R2C,
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−    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,
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−    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 */