mdct15.h 1.78 KB
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/*
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 * Copyright (c) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
 *
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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
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
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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
 * 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
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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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#ifndef AVCODEC_MDCT15_H
#define AVCODEC_MDCT15_H
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#include <stddef.h>

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#include "fft.h"
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typedef struct MDCT15Context {
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    int fft_n;
    int len2;
    int len4;
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    int inverse;
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    int *pfa_prereindex;
    int *pfa_postreindex;

    FFTContext ptwo_fft;
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    FFTComplex *tmp;

    FFTComplex *twiddle_exptab;

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    /* 0 - 18: fft15 twiddles, 19 - 20: fft5 twiddles */
    FFTComplex exptab[21];
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    /**
     * Calculate a full 2N -> N MDCT
     */
    void (*mdct)(struct MDCT15Context *s, float *dst, const float *src, ptrdiff_t stride);

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    /**
     * Calculate the middle half of the iMDCT
     */
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    void (*imdct_half)(struct MDCT15Context *s, float *dst, const float *src,
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                       ptrdiff_t src_stride, float scale);
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} MDCT15Context;
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/**
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 * Init an (i)MDCT of the length 2 * 15 * (2^N)
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 */
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int ff_mdct15_init(MDCT15Context **ps, int inverse, int N, double scale);
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/**
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 * Frees a context
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 */
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void ff_mdct15_uninit(MDCT15Context **ps);
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#endif /* AVCODEC_MDCT15_H */