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https://github.com/FFmpeg/FFmpeg.git
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65 lines
2.1 KiB
C
65 lines
2.1 KiB
C
/*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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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#define CONFIG_FFT_FLOAT 0
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#include "mdct.c"
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/* same as ff_mdct_calcw_c with double-width unscaled output */
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void ff_mdct_calcw_c(FFTContext *s, FFTDouble *out, const FFTSample *input)
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{
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int i, j, n, n8, n4, n2, n3;
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FFTDouble re, im;
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const uint16_t *revtab = s->revtab;
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const FFTSample *tcos = s->tcos;
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const FFTSample *tsin = s->tsin;
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FFTComplex *x = s->tmp_buf;
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FFTDComplex *o = (FFTDComplex *)out;
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n = 1 << s->mdct_bits;
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n2 = n >> 1;
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n4 = n >> 2;
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n8 = n >> 3;
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n3 = 3 * n4;
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/* pre rotation */
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for(i=0;i<n8;i++) {
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re = RSCALE(-input[2*i+n3] - input[n3-1-2*i]);
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im = RSCALE(-input[n4+2*i] + input[n4-1-2*i]);
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j = revtab[i];
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CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
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re = RSCALE( input[2*i] - input[n2-1-2*i]);
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im = RSCALE(-input[n2+2*i] - input[ n-1-2*i]);
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j = revtab[n8 + i];
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CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
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}
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s->fft_calc(s, x);
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/* post rotation */
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for(i=0;i<n8;i++) {
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FFTDouble r0, i0, r1, i1;
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CMULL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]);
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CMULL(i0, r1, x[n8+i ].re, x[n8+i ].im, -tsin[n8+i ], -tcos[n8+i ]);
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o[n8-i-1].re = r0;
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o[n8-i-1].im = i0;
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o[n8+i ].re = r1;
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o[n8+i ].im = i1;
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}
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}
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