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/*
* copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
*
* 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
*/
#include "fft.h"
#include "synth_filter.h"
static void synth_filter_float(FFTContext *imdct,
float *synth_buf_ptr, int *synth_buf_offset,
float synth_buf2[32], const float window[512],
float out[32], const float in[32], float scale)
{
float *synth_buf= synth_buf_ptr + *synth_buf_offset;
int i, j;
imdct->imdct_half(imdct, synth_buf, in);
for (i = 0; i < 16; i++){
float a= synth_buf2[i ];
float b= synth_buf2[i + 16];
float c= 0;
float d= 0;
for (j = 0; j < 512 - *synth_buf_offset; j += 64){
a += window[i + j ]*(-synth_buf[15 - i + j ]);
b += window[i + j + 16]*( synth_buf[ i + j ]);
c += window[i + j + 32]*( synth_buf[16 + i + j ]);
d += window[i + j + 48]*( synth_buf[31 - i + j ]);
}
for ( ; j < 512; j += 64){
a += window[i + j ]*(-synth_buf[15 - i + j - 512]);
b += window[i + j + 16]*( synth_buf[ i + j - 512]);
c += window[i + j + 32]*( synth_buf[16 + i + j - 512]);
d += window[i + j + 48]*( synth_buf[31 - i + j - 512]);
}
out[i ] = a*scale;
out[i + 16] = b*scale;
synth_buf2[i ] = c;
synth_buf2[i + 16] = d;
}
*synth_buf_offset= (*synth_buf_offset - 32)&511;
}
av_cold void ff_synth_filter_init(SynthFilterContext *c)
{
c->synth_filter_float = synth_filter_float;
if (ARCH_ARM) ff_synth_filter_init_arm(c);
if (ARCH_X86) ff_synth_filter_init_x86(c);
}
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