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https://github.com/FFmpeg/FFmpeg.git
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65 lines
2.4 KiB
C
65 lines
2.4 KiB
C
/*
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* copyright (c) 2008 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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#include "fft.h"
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#include "synth_filter.h"
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static void synth_filter_float(FFTContext *imdct,
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float *synth_buf_ptr, int *synth_buf_offset,
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float synth_buf2[32], const float window[512],
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float out[32], const float in[32], float scale)
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{
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float *synth_buf= synth_buf_ptr + *synth_buf_offset;
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int i, j;
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imdct->imdct_half(imdct, synth_buf, in);
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for (i = 0; i < 16; i++){
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float a= synth_buf2[i ];
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float b= synth_buf2[i + 16];
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float c= 0;
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float d= 0;
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for (j = 0; j < 512 - *synth_buf_offset; j += 64){
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a += window[i + j ]*(-synth_buf[15 - i + j ]);
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b += window[i + j + 16]*( synth_buf[ i + j ]);
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c += window[i + j + 32]*( synth_buf[16 + i + j ]);
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d += window[i + j + 48]*( synth_buf[31 - i + j ]);
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}
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for ( ; j < 512; j += 64){
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a += window[i + j ]*(-synth_buf[15 - i + j - 512]);
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b += window[i + j + 16]*( synth_buf[ i + j - 512]);
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c += window[i + j + 32]*( synth_buf[16 + i + j - 512]);
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d += window[i + j + 48]*( synth_buf[31 - i + j - 512]);
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}
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out[i ] = a*scale;
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out[i + 16] = b*scale;
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synth_buf2[i ] = c;
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synth_buf2[i + 16] = d;
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}
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*synth_buf_offset= (*synth_buf_offset - 32)&511;
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}
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av_cold void ff_synth_filter_init(SynthFilterContext *c)
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{
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c->synth_filter_float = synth_filter_float;
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if (ARCH_ARM) ff_synth_filter_init_arm(c);
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}
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