yading@10: /*
yading@10:  * copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "fft.h"
yading@10: #include "synth_filter.h"
yading@10: 
yading@10: static void synth_filter_float(FFTContext *imdct,
yading@10:                            float *synth_buf_ptr, int *synth_buf_offset,
yading@10:                            float synth_buf2[32], const float window[512],
yading@10:                            float out[32], const float in[32], float scale)
yading@10: {
yading@10:     float *synth_buf= synth_buf_ptr + *synth_buf_offset;
yading@10:     int i, j;
yading@10: 
yading@10:     imdct->imdct_half(imdct, synth_buf, in);
yading@10: 
yading@10:     for (i = 0; i < 16; i++){
yading@10:         float a= synth_buf2[i     ];
yading@10:         float b= synth_buf2[i + 16];
yading@10:         float c= 0;
yading@10:         float d= 0;
yading@10:         for (j = 0; j < 512 - *synth_buf_offset; j += 64){
yading@10:             a += window[i + j     ]*(-synth_buf[15 - i + j      ]);
yading@10:             b += window[i + j + 16]*( synth_buf[     i + j      ]);
yading@10:             c += window[i + j + 32]*( synth_buf[16 + i + j      ]);
yading@10:             d += window[i + j + 48]*( synth_buf[31 - i + j      ]);
yading@10:         }
yading@10:         for (     ; j < 512; j += 64){
yading@10:             a += window[i + j     ]*(-synth_buf[15 - i + j - 512]);
yading@10:             b += window[i + j + 16]*( synth_buf[     i + j - 512]);
yading@10:             c += window[i + j + 32]*( synth_buf[16 + i + j - 512]);
yading@10:             d += window[i + j + 48]*( synth_buf[31 - i + j - 512]);
yading@10:         }
yading@10:         out[i     ] = a*scale;
yading@10:         out[i + 16] = b*scale;
yading@10:         synth_buf2[i     ] = c;
yading@10:         synth_buf2[i + 16] = d;
yading@10:     }
yading@10:     *synth_buf_offset= (*synth_buf_offset - 32)&511;
yading@10: }
yading@10: 
yading@10: av_cold void ff_synth_filter_init(SynthFilterContext *c)
yading@10: {
yading@10:     c->synth_filter_float = synth_filter_float;
yading@10: 
yading@10:     if (ARCH_ARM) ff_synth_filter_init_arm(c);
yading@10: }