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110 lines
3.2 KiB
C
110 lines
3.2 KiB
C
/*
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* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
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*
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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
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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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
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* 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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*/
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#pragma once
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#define CMUL(dre, dim, are, aim, bre, bim) do { \
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(dre) = (are) * (bre) - (aim) * (bim); \
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(dim) = (are) * (bim) + (aim) * (bre); \
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} while (0)
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#include <stdint.h>
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#include "compat.h"
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typedef float FFTSample;
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typedef struct FFTComplex {
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FFTSample re, im;
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} FFTComplex;
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typedef struct FFTContext FFTContext;
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typedef float FFTDouble;
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/* FFT computation */
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enum mdct_permutation_type {
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FF_MDCT_PERM_NONE,
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FF_MDCT_PERM_INTERLEAVE,
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};
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struct FFTContext {
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int nbits;
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int inverse;
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uint16_t *revtab;
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FFTComplex *tmp_buf;
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int mdct_size; /* size of MDCT (i.e. number of input data * 2) */
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int mdct_bits; /* n = 2^nbits */
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/* pre/post rotation tables */
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FFTSample *tcos;
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FFTSample *tsin;
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/**
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* Do the permutation needed BEFORE calling fft_calc().
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*/
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void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
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/**
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* Do a complex FFT with the parameters defined in ff_fft_init(). The
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* input data must be permuted before. No 1.0/sqrt(n) normalization is done.
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*/
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void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
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void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
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void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
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void (*mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
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enum mdct_permutation_type mdct_permutation;
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};
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#define COSTABLE(size) \
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DECLARE_ALIGNED(32, FFTSample, ff_cos_##size)[size/2]
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extern COSTABLE(16);
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extern COSTABLE(32);
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extern COSTABLE(64);
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extern COSTABLE(128);
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extern COSTABLE(256);
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extern COSTABLE(512);
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extern COSTABLE(1024);
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extern COSTABLE(2048);
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extern COSTABLE(4096);
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extern COSTABLE(8192);
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extern COSTABLE(16384);
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extern COSTABLE(32768);
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extern COSTABLE(65536);
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extern FFTSample* const ff_cos_tabs[17];
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/**
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* Initialize the cosine table in ff_cos_tabs[index]
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* @param index index in ff_cos_tabs array of the table to initialize
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*/
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void ff_init_ff_cos_tabs(int index);
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/**
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* Set up a complex FFT.
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* @param nbits log2 of the length of the input array
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* @param inverse if 0 perform the forward transform, if 1 perform the inverse
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*/
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int ff_fft_init(FFTContext *s, int nbits, int inverse);
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void ff_fft_end(FFTContext *s);
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int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale);
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void ff_mdct_end(FFTContext *s);
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